TRANSPORT OF MATERIALS IN LIVING THINGS
Transport
system in living organisms refers to the movement of materials within the body
of organism
The body of an organism needs the essential materials for life process. E.g. nutrients, water, mineral salts, hormones, waste products which eliminated and end product of metabolism.
The body of an organism needs the essential materials for life process. E.g. nutrients, water, mineral salts, hormones, waste products which eliminated and end product of metabolism.
The materials need to be transported from one
point of the body to another either for breakdown or to be taken to other
parts.
Example: materials
are transported; the environment into the organism, from one part of the
organism to another, from the organism into the environment.
i.e. During
nutrition organism take in food substances that they need to provide them with
energy. Food must also be transported to all parts of the organism.
•
Respiration
requires oxygen, which must be taken in from the environment.
•
During
excretion, waste materials from the organism are transported to the excretory
organs and removed from the body.
•
Movement
and locomotion of impulses to the relevant organs
•
Reproduction
requires the movement of gametes (sex cells) or the transportation of gametes.
•
Growth
requires the production and transportation of growth hormones to the growing
parts of the organism.
Importance of Transport in living Things.
a. Transport
enables both organic and inorganic materials to move from one area of the body
to another.
Example. During
photosynthesis plants make their own food in the leaves. The manufacture food
in the leaves. The manufacture food has to be transported to other parts of the
body of plant for either storage or use.
b. Transport
ensures that essential materials such as
nutrients, oxygen, water, mineral salts, hormones and other are supplied to the
cells to enable them rum out their activities.
c End-
products of metabolism and all waste are removed out through the media of
transport.
Eg. Small animals
such amoeba and other protozoans carry out the exchange of material by simple
diffusion through their body surface.
Role of Diffusion in
living organism
d. Absorption
Digested food
eg. Amino acid and glucose diffuse
across the wall of the ileum to the blood system. Plants absorbed most of the
minerals salts by diffusion.
e. Transport of food
Manufactured food
from the leaves is distributed to other parts of the plant by diffusion.
f. Excretion of Nitrogenous Wastes
Nitrogenous eg.
Urea, ammonia leaves the cells by diffusion.
g. Gaseous Exchange
•
In plants
Carbon dioxide and
oxygen are exchanged through the stomata in leaves, cuticle or lenticels in
stems. Plants take oxygen during the night for respiration and give out carbon
dioxide. During the day carbon dioxide is taken in and issues in
photosynthesis.
•
In animals:
Exchange of gases
(carbon dioxide and oxygen) occurs across the respiratory surface eg.
Lungs,skin and gills by diffusion.
Factors that affect the rate of Diffusion
•
Size of molecules
Small and light
molecules diffuse faster than larger and heavy molecules.
•
Temperature:
Increase in
temperature increase that rate of diffusion
•
Thickness of membranes and tissues.
Thin membranes enhance higher rate of diffusion than thick membranes.
•
Concentration
gradient (diffusion gradient).
The greater of the difference of
two concentration gradient the greater the rate of diffusion.
•
Surface
area to volume ratio
The higher ratio the
greater the rate of diffusion.
Human and higher
animals the exchange of materials is carried out by a circulatory system.
N.B Transport of
materials may take place through the process of
•
Diffusion
•
Osmosis
•
Mass
flow.
Methods of Transport.
Life processes in a
organism take place at the cell level.
It is necessary for
the substance to move in and out of the cells.
There are two ways
through which substances can move across the cell membrane.
•
Passive
transport- which occurs spontaneously without the need of energy.
•
Active
transport- where the cell has to use energy to move materials through the cell
membrane.
•
Processes
like diffusion, osmosis and mass flow involve passive transport.
Diffusion, osmosis and mass flow
Diffusion: Is the movement of particles from a region of high concentration to
a region of low concentration.
A difference in the
concentration of a substance between two regions is known as concentration
gradient.
Diffusion causes the
particles to move from the region where is highly concentrated to the region
where there is low concentration. Diffusion continues until the particles are
distributed evenly through.
Diffusion can be
gases or liquids eg. A scent of flower, colour of potassium permanganate when a
crystal is put in water.
 |
| Fig .The process of diffusion |
OSMOSIS
Osmosis is the process by which water molecules move from lowly- concentrated
solution (dilute solution) to highly
concentrated solution strong solution) across semi- permeable membrane.
or
Ia process by which solvent molecules pass through a selectively permeable membrane from a region of high-solvent conentration to region of low-solvent concentration
or
Ia process by which solvent molecules pass through a selectively permeable membrane from a region of high-solvent conentration to region of low-solvent concentration
Osmosis is also
defined as the process by which water molecules move from a region of high
water concentration through a semi- permeable membrane.
For Osmosis to take place ,there must be two solution separated by semi-permeable membrane
Types of solution
i.Hypotonic solution-is the solution with greater volume of water and lesser quantity. This solution has lower water potential
ii.Hypertonic solution is the solution with lesser volume of water and a greater volume of solute.This solution has higher water potential
iii.Isotonic solution.Is the solution with the same water potential
For Osmosis to take place ,there must be two solution separated by semi-permeable membrane
Types of solution
i.Hypotonic solution-is the solution with greater volume of water and lesser quantity. This solution has lower water potential
ii.Hypertonic solution is the solution with lesser volume of water and a greater volume of solute.This solution has higher water potential
iii.Isotonic solution.Is the solution with the same water potential
Effects of osmosis in organisms.
a. Osmosis and animal cells
-When an animal cells is placed in a hyportonic solulion, It absorb water.If it remains in the solution for long time, it absorb the excess amount of water. and final burst due to the excessive internal pressure(Haemolysis)
Haemolysis is the bursting of animal cells due to excessive internal pressure when absorb excess water when placed in hypotonic solution
-When an
animal cell is placed in a pypertonic solution, it loses water.If remains in the solution for long time, it loses a lot of water , shrinks and shrives(Crenation)
Crenation Is shrinking and shriving of an animal cells when loses of water in hypertonic solution
-When an animals is placed in isotonic solution there is equal movement of water in and out of cell
b.Osmosis and plant cells
-In isotonic solution, Plant cells neither loses nor gain water
-In hypotonic solution plant cell absorb water,causing the cell membrane to push against the cell wall the cell is said to be Turgid
a. Osmosis and animal cells
-When an animal cells is placed in a hyportonic solulion, It absorb water.If it remains in the solution for long time, it absorb the excess amount of water. and final burst due to the excessive internal pressure(Haemolysis)
Haemolysis is the bursting of animal cells due to excessive internal pressure when absorb excess water when placed in hypotonic solution
-When an
animal cell is placed in a pypertonic solution, it loses water.If remains in the solution for long time, it loses a lot of water , shrinks and shrives(Crenation)
Crenation Is shrinking and shriving of an animal cells when loses of water in hypertonic solution
-When an animals is placed in isotonic solution there is equal movement of water in and out of cell
b.Osmosis and plant cells
-In isotonic solution, Plant cells neither loses nor gain water
-In hypotonic solution plant cell absorb water,causing the cell membrane to push against the cell wall the cell is said to be Turgid
Turgidity: when a cell is placed into a solution of lower concentration than
its cell sap, water moves into the cell until the cell can no longer absorb any
more water.
Turgidity can be
referred to as a condition where a cell is full of water such that it can no
longer absorb any more water from the surroundings.
It does not burst because the cell membrane exerts pressure on the cell wall which restrict additional intake of water
Turgidity help plants to maintain their shape
- In hyperpotonic solution,plant cellulose water.This causes the vacuole to shrink and the surface of the cell membrane to pull away from the cell wall, making flaccid(plsmolyzed)
It does not burst because the cell membrane exerts pressure on the cell wall which restrict additional intake of water
Turgidity help plants to maintain their shape
- In hyperpotonic solution,plant cellulose water.This causes the vacuole to shrink and the surface of the cell membrane to pull away from the cell wall, making flaccid(plsmolyzed)
Plasmolysis is the phenomenon whereby the cell losses water
to the surrounding when it is surrounded with a concentrated solution that its
cell saps.
- If a plasmolyzed cell is placed in a hypotonic solution,It absorbs water and becomes turgid
Osmosis and unicellular organism
unicellular organisms that live in fresh water.Example amoeba, and Euglena are hypertonic solution to their surrounding so water enters the organism by osmosis
- These organism have contractile vacuole which collects the excess water and remove it from the cell.This prevent cell from bursing
- If a plasmolyzed cell is placed in a hypotonic solution,It absorbs water and becomes turgid
Why plants wilt or die when fertilizers are
excessively applied?
Because the soil becomes more concentrated than the
cell sap, hence plant lose water to the soil by osmosis.
Osmosis and unicellular organism
unicellular organisms that live in fresh water.Example amoeba, and Euglena are hypertonic solution to their surrounding so water enters the organism by osmosis
- These organism have contractile vacuole which collects the excess water and remove it from the cell.This prevent cell from bursing
Importance of osmosis in organisms
•
Body cells obtain water from the blood by
osmosis. Water also moves from the soil to plant root hairs by osmosis
•
It
enables the young plants to get their support due to turgidity. Thus, their
stems stand upright and their leaves are held out firmly.
•
It
assists in opening and closing of the stomata.
•
Osmosis
can also cause other cells to die, burst or become weak
·
When red
blood cells are surrounded by a very dilute solution they burst.
·
When
plants are exposed to conditions in which water is lost to the atmosphere
faster than it can be obtain from weak, the stem drops and the leave become
limp.
Mass Flow
Mass flow is the bulk movement of substances from one region to another due to
the difference in pressure between two regions.
or
is the movement of fluids within a cell or along a vessel or tube without passing through a membrane
or
is the movement of fluids within a cell or along a vessel or tube without passing through a membrane
Mass flow occurs
within a cell along a vessel
Mass flow in large
complex organisms where substances are required in large amounts and also how
to be transported over large distances.
Examples of systems where mass flow occurs
•
The circulatory system in animals
•
The
lymphatic system (flow of lymph) is animals.
•
Transport
of manufactured food material in plants from the site of manufacture (source)
to the point of the use (sink) through the phloem. This process is called
translocation.
Differences between diffusion, osmosis and
mass flow
Differences between
diffusion, osmosis and mass flow can base on substance transported,
transportation structures and cause of movement.
no
|
Characteristic
|
Diffusion
|
osmosis
|
Mass flow
|
1
|
Substance transported
|
Gasses and liquids
|
water
|
Solids, liquids and gases
|
2
|
Transportation structure
|
None
|
Semi-permeable membrane
|
Cytoplasm or vessels
|
3
|
Cause
of movement
|
Diffusion gradient
|
Osmotic pressure
|
Difference in pressure
|
Comparison of diffusion and osmosis
Diffusion and
Osmosis are similar in that both processes involve movement of molecules or
ions from a region of high concentration to one of low concentration.
However will diffusion refers to the movement of any type of molecules, osmosis refers to the movement of water molecules only across a semi-permeable membrane.
However will diffusion refers to the movement of any type of molecules, osmosis refers to the movement of water molecules only across a semi-permeable membrane.
TRANSPORT OF MATERIALS IN MAMMALS
The structure of the mammalian Heart:
The mammalian heart
consists largely of cardiac muscles a specialized tissue which is capable of
rhythmical contraction and relaxation over a long period without fatique.
The human heart is
approximately the size of a clenched first. It is located in the chest cavity
between the two lungs.
The external structure of the mammalian heart
 |
| fig.External structure of the mammalian heart. |
•
The
mammalian heart is broader at the top and narrower at the bottom.
•
It is
enclosed by a double layer of tough inelastic membranes called the pericardium.
The membranes prevent the heart from over expending when it is beating fast.
•
The
pericardium also secretes a fluid celled pericardial fluid. The fluid enables
the membrane to move smoothly against each other.
The wall of the heart has three layers
•
The
epicardium which is the outer protective layer
•
The
myocardium which is the middle layer
•
The
endocardium which is the innermost layer.
•
The
coronary artery supplies the heart with oxygenated blood
•
The
coronary vein carries blood containing waste materials away from the heart
•
The vena
cava and pulmonary vein bring blood from the rest of the body to the heart.
•
The
aorta and pulmonary artery transport blood from the heart to the rest of the
body.
The internal structure of the mammalian heart.
The internal structure of the mammalian heart.
Parts of the Heart
The heart has four chambers.
•
Right
auricle
•
Right
ventricle
•
Left
auricle
•
Left
ventricle
a.The walls of the ventricles are thicker than those of the Auricles..This is because the ventricles pump blood to a greater distance
The auricles pump blood to the ventricles
b.The left ventricle is thicker than right ventricle Because the left ventricle pumps blood to the rest of the body while right venticle pumps to the lungs
The valves of Heart
The valve has flaps that ensure that blood flowing one direction only
i Tricuspid valve
There found between right auricle and right ventricles
Function .Prevent blood from flowing back into the right auricle
ii.Bicuspid valve
There are found between left auricle and left ventricle
function. prevent blood from back in
iii.Semi-lunar valves
Are located at the base of the pulmonary artery and Aorta to prevent blood from flowing back into the ventricle
The right and left sides of the heart are separated by the Septum
The Septum is a thick muscular wall that prevents mixing of oxygenet and deoxygenated blood.
The flow of blood through the heart
The venacava brings deoxygenated blood to the heart and received in Right auricle: The right auricle/trium receives deoxygenated(low amount of oxygen).
Branches of vena cava
a.The superior vena cava- transport deoxygenated blood from upper parts of the body. Example.Head,,neck and upper limb
b.The inferior vena cava-Transpors deoxygenated blood from the lower parts of the body .Example kidney,lower limb, liver
The auricles pump blood to the ventricles
b.The left ventricle is thicker than right ventricle Because the left ventricle pumps blood to the rest of the body while right venticle pumps to the lungs
The valves of Heart
The valve has flaps that ensure that blood flowing one direction only
i Tricuspid valve
There found between right auricle and right ventricles
Function .Prevent blood from flowing back into the right auricle
ii.Bicuspid valve
There are found between left auricle and left ventricle
function. prevent blood from back in
iii.Semi-lunar valves
Are located at the base of the pulmonary artery and Aorta to prevent blood from flowing back into the ventricle
The right and left sides of the heart are separated by the Septum
The Septum is a thick muscular wall that prevents mixing of oxygenet and deoxygenated blood.
The flow of blood through the heart
The venacava brings deoxygenated blood to the heart and received in Right auricle: The right auricle/trium receives deoxygenated(low amount of oxygen).
Branches of vena cava
a.The superior vena cava- transport deoxygenated blood from upper parts of the body. Example.Head,,neck and upper limb
b.The inferior vena cava-Transpors deoxygenated blood from the lower parts of the body .Example kidney,lower limb, liver
Right ventricle- Receives deoxygenated blood from the right
atrium. Right ventricle pumps blood to
the lungs via the pulmonary artery.
Left auricle-
receives oxygenated blood from the lungs via the pulmonary artery.
Left ventricle: Receives oxygenated blood from the left
auricle. The left ventricle is more muscular than the right ventricle. This is
because it pumps blood with pressure to the whole body.
Pulmonary artery
carries deoxygenated blood from the right ventricle to the lungs. Blood is
pumped to the lungs to collect oxygen.
Pulmonary vein
carries oxygenated blood from the lungs to the heart.
Vena cava: Deoxygenated blood enters the
heart through vena cava. Blood from all parts of the body above the heart
enters the heart via superior venacava.
Blood from all parts
of the body below the heart enters the heart via inferior venacava super and
inferior venacava join to form the venacava, which drains blood to the heart in
the right atrium. The blood then enters the right ventricle and it is then
pumped to the lungs through pulmonary artery.
Blood goes to the
lungs to collect oxygen oxygenated blood from lungs comes back to the heart
through the aorta to all parts of the
body.
The walls of the
heart on the left ventricle are more muscular so that blood can be pumped at a
higher pressure to enable it to travel to all parts of the body
Adaptation of the heart to its function
Muscular walls
Cardiac muscle
Valves
Septum
Tendons
Connection to large blood vessels
Sinoatrial node
Coronary artery and coronary vein
|
•
Contract to pump
blood
•
Contract and relax
continuously without being fatigued. This ensures continuous pumping of
blood.
•
Ensure blood
flowing only one direction.
•
Separates
oxygenated blood from deoxygenated
blood
•
Prevent valves
from turning inside out.
•
Enable
transportation of deoxygenated blood
from all parts of the body to the heart to all parts of the body
•
Sets time and rate
of contraction of cardiac muscle.
•
The coronary
artery nourishes the heart and supplies if with oxygen.
The
coronary vein removes waste which would harm the heart if left to accumulate.
|
Arteries
•
They
carry blood from the heart into the body tissues
•
Blood
flow rate is rapid, irregular with pulsation.
•
They
have thick- elastic walls. Blood flows in them with high pressure.
•
They are
situated deep in the body
• All arteries transport oxygenated blood except of pulmonary artery which carry deoxygenated blood.
•
With the
exception of the largest artery (aorta)
, arteries have no values
•
They
have small lumen and carry blood which
is pink in colour
Veins:
•
They
carry blood towards the heart from the body tissue
•
Blood
flow rate is slow, regular and has no pulsation.
•
They
have thin walls. Blood flow with low pressure
•
They are
situated just beneath the skin
•
With the
exception of pulmonary vein all veins carry deoxygenated blood.
•
They
have wind lumen and they carry blood which is reddish in colour.
•
Most
veins have values to prevent back flow as blood in them moves with very low
pressure.
Capillaries
•
They are
tiny vessels with only one cell thick
•
Blood
flow from arteries to vein through
capillaries
•
Blood
flows rate very slow because of falling pressure.
•
They
have no values
•
They run
through all body tissues
•
Blood
plasma (water and dissolved substances passes through walls. Fluid squeezed out
of the blood capillaries into the body tissues is called tissue fluid.
•
Are
numerous to increase the surface area
•
Are very close to the tissue for easy exchange
materials
•
Have
small lumen causing blood flow at high pressure, which forces materials out of
them
Differences between arteries and capillaries
no
|
Arteries
|
Veins
|
Capillaries
|
1
|
Have narrow smooth lumens
|
•
Have wide irregular lumens
|
•
Have narrow smooth lumens
|
2
|
Have thick muscular walls
|
•
Have thin, less
muscular walls
|
•
Have one cell thick walls
|
3
|
Lack valves except where they are connected
to the heart
|
•
Have valves at regular intervals
|
3.lack valves
|
4
|
Transport blood at high pressure
|
•
Transport blood at low pressure
|
4.Transport blood at low pressure
|
5
|
Transport blood away from the heart
|
•
Transport blood towards the heart
|
5.transport blood within the tissue
|
6
|
Transport oxygenated blood, except the
pulmonary artery
|
•
Transport deoxygenated blood except
pulmonary vein
|
6. Transport either oxygenated or
deoxygenated blood.
|
7
|
Contract and relax to create a pulse
|
•
Blood flows
smoothy
|
7.Blood flows smoothly
|
THE BLOOD
Blood is a vital
body fluid consisting of plasma platelets, Red blood cells and white blood
cells.
An adult human has 4
to 6 litres of blood
The PH of blood is
7.4.
Major components of
blood
•
Red
blood cells
•
White blood cells
•
Platelets
•
Plasma
1.Red blood cells also
called red Corpuscles or erythrocytes
Formation: Formed in
bone marrow of short bones vertebrae.
Characteristics
•
Are biconcave i.e disc- shaped
•
Have no
nucleus
•
Have
short life span of about 120 days
Functions.
- transport oxygen
and small quantities of carbondioxide
Adaptions of erythrocytes
They are numerous
and hence increase surface area
absence of nucleus
creates more room for more haemoglobin.
2.white bloods cells.
(Leucocyctes)
Formation:
Formed in the also
formed in the marrow of long bones eg. humerus. They are also formed in the
lymph mode.
Characteristics
- have the nucleus
- lack haemoglobin
- They have no definite shape. ie are amoeboid
-
Are
fewer in number
Functions.
- Some make antibodies: and some engulf foregn particles including
bacteria.
3.Plasma
Plasma is a pale
yellow fluid in which substances dissolved 99% of plasma is water.
Dissolved substances include
- Food substances eg. Glucose, amino acids,
vitamins
Mineral salts
Enzymes
Waste products eg.
Urea, carbon dioxide
Fibrinogen helps in
blood clotting
Functions:
1. Transportation of
- Hormones and nutrients
- Waste products from tissues to excretory
organs
- Red blood cells which inturn facilitates
oxygen and carbondixide transportation
- Mineral ions such as sodium, potassium and
chlorides
- Regulation of body temperature
- Regulation of body PH
4.Platelets/Thrombocytes
Characteristics
- are star-shaped
Have no nucleus
- one millimiter is approximalely 5,000 to 10.000
- one millimiter is approximalely 5,000 to 10.000
Function: Are involved in blood clotting. Blood clots when it is exposed to
air
Platelets contain a chemical substance called
thromboplastin
The
effects of HIV on white blood cells
• Human
immunodeficiency virus (HIV) affects the immune system
• HIV
replicates (increase in number in a particular type of white blood cell which
acts as the host for this virus is a type of lymphocyte called helper-T
cells.These cells are essential for body immunity
• HIV virus
has a protein envelope that can only bind to its receptor called CD4 found on
the cell membrane of the helper-T cell.When it enters the humn body, HIV fuses
its protein envelope with the CD4 then enters the cell.
• Once
inside the cell, the virus become part of the helper-T cell and replicate
together with it as it undergoes division..This increases the amount of HIV in
the blood.HIV destroys helper-t cells resulting in the reduction of the number
of helper-T cells and reducing the CD4 count
WAYS HIV DESTROYS HELPER-T CELLS
i.It reproduce inside the
helper-T cells, then ruptures the cells's membrane and the new viruses are
released
ii.It alters the helper-T cells
so that when it respond to an infection, it kills itself instead of diving to
form new cells
iii.It marks helper-t cells as
targets for destruction by other cells in the immune system
iv.It causes the fusion of many
helper-Tcells to form a giant cells
Blood Groups and
Blood Transfusion.
• grouping
of human blood is done using the ABO system and the Rhesus factor
• The red
blood cells in humans have special
antigens which determine blood groups
In addition to these
antigens are other proteins known as antibodies in the plasma when antigen
present antigenB is present when
antibody `b` is present when antigen B is present antibody` a `is present .when
no antigen is present both antibodies `a` and `b`are present.
BLOOD GROUPS, ANTIGENS AND ANTIBODY
Antigen the membrane
|
Antibody in the plasma
|
Blood
Group
|
A
|
b
|
A
|
B
|
a
|
B
|
A and B
|
None
|
AB
|
No antigens
|
a and b
|
O
|
RHESUS FACTOR
Rhesus factor is another antigen (or protein). If present in the red blood cells, the individual is said to be Rhesus positive (Rh+) while its absence in an individual body makes him or her Rhesus negative
If Rh+ is transfused into a person without it (Rhesus negative) antibody production is induced in line with the usual immune response. For this reason, before transfusion, blood is matched with respect to is the factor named after the Rhesus monkey in which it is was first observed
Rh+ -When rhesus is present in the red blood cell
RH-.- If it is absent
-If person’s blood is A+ means that the blood group is a and its Rhesus factor is positive
-If person’s blood is A- . means that the blood group
is A and lacks Rhesus factor
- there are also B+ or B-,O+or
O- and AB+ or AB-
If a rhesus negative(RH-) woman marries a rhesus
positive(RH+) man, their children are highly likely to be rhesus positive
.During the last monthly of pregnancy, the rhesus antigen from the foetus
passes into the mother blood. This causes the mother’s body to produce the
antibodies which destroy some of the foetus’s red blood cells.
This destruction is minimal inthe first chid but
tin the children that follow, a lot of destruction
could take place, killing the foetus. this is called haemolytic of diseases o
anew born baby(erthroblastosis foetalis
Blood Transfusion
•
This is
the transfer of blood from a donor to recipient
•
Blood is
transferred to an individual who has
lost an excessive amount of blood
•
Blood
transfusion is successful when the recipients blood accepts the donated blood
with no agglutination
•
People with blood O are Known as universal
donors because having no antigen to be agglutinated, they can donate blood to
any blood group
•
People
with blood group AB are known as universal recipients they can receive blood
from any group because they don’t have any antibodies to agglutinate donated
blood.
RECIPIENT
Donor’s Group
|
Recipient’s
|
Group
|
||
A
|
B
|
AB
|
O
|
|
A
|
V
|
X
|
V
|
x
|
B
|
x
|
V
|
V
|
x
|
AB
|
x
|
X
|
v
|
x
|
O
|
v
|
V
|
v
|
v
|
V) This indicates no agglutination
(x) This sign indicates agglutination
(
Things to note
before blood Transfusion. (Precautions)
•
Doctor
should establish the blood groups of the
receipt to prevent agglutination
•
The
blood should be screened to ensure that there are no pathogens which can cause diseases such as HIV and
AIDS, syphilis and hepatitis B.
•
Donated
blood is stored in special bags and an anticoagulant is added to prevent it
from coagulating.
•
Donated
blood is kept in a refrigerator, for a maximum of 21 days. After that it
expires and should not be used.
•
Transfusion
should be done only when extremely necessary.
Advantages of blood Transfusion
•
It
ensures rapid replacement of blood lost from the body eg. During surgery or or
due to an accident
•
Blood
transfusion enables the victim of sickle-cell anemia to survive long.
Disadvantages of Blood Transfusion
•
If blood
is not matched with respect to Rhesus factor as well as the ABO system the
receipt can severally be harmed or sometimes die because of blood
agglutination.
•
If blood
is contaminated with HIV/AIDS, the receipt is likely to be affected with it.
•
Sometimes
the donor’s health can be affected if blood is produced in excess.
Blood circulation:
Blood circulation is
the movement of blood from the heart to all parts of the body and back to the
heart.
Human being exhibit
double circulation whereby the blood passes through the heart twice for each
complete circulation.
In less complex
organisms like fish blood goes through the heart once and this is known as
single circulation.
Types of circulatory system.
Open circulatory system, consist of blood which is not completely
closed within vessels. This is suitable for small organisms, invertebrates like
spiders, crabs, lobster, snails, oysters and clams. They use the system to
transport food and waste while a different system transports gases as in
insects.
The circulatory fluid bathes the cells directly and
only slowly percolates through the tissues, returning to the heart by a system
of collecting vessels.
Closed circulatory system, has blood contained in unbroken network of
vessels, where blood circulate within a continuous system of blood vessels.
This allows high pressure and a rapid rate of flow to be maintained. The blood
of all vertebrates (and invertebrates like earthworm and squid) also have a
closed circulatory system
Double
circulation.
These are pulmonary
circulation and systemic circulation. During one complete circuit, blood
passes twice through the heart, i.e.
the blood is pumped by the heart along arteries to capillaries and then
returned to the heart by veins.
Pulmonary Circulation
During pulmonary
circulation deoxygenated blood is brought to the heart though the vena cava.
This blood is emptied into the right auricle. The right auricle pumps blood to
the right ventricle. When the right ventricle contracts it pumps blood to the
lungs through the pulmonary artery.
In lungs the blood
is oxygenated then it flows back to the heart through the pulmonary vein.
Systemic circulation
In systemic
circulation the pulmonary vein transports blood to the left auricle. The left
auricle them pumps the blood into the left ventricle. The left ventricle has
strong muscles that pump blood to all parts of the body through aorta.
•
The
contractions of the heart of the heart are known as systole which the
relaxation of the heart is known as distole.
•
The
semilunar valve opens to allow blood flow through the pulmonary artery and aorta.
•
The cuspid valves (bicuspid and tricuspid) close
to prevent backward flow of blood to the atria (auricle)
•
The
ventricles contract pushing blood out of them
•
Blood fills
the auricle (atria)
During Diastole
- The semilunar
valves close down to prevent backward flow of blood from the pulmonary artery
and aorta in.
- The bicuspid and tricuspid valves open to
allow blood in the atria (auricle to flow into the ventricles
Blood pressure
during systole is 120m Hg.
Blood pressure
during diastole is 80 mm Hg
= 120/80 mm Hg
The instrument used
to measure blood pressure is called sphygmomanometer.
Importance of blood circulation
1. It is enables the transportation of cell
requirements such as oxygen and nutrients to all the body tissue
2. It ensures that waste products from the cells
are removed so as to prevent accumulation of waste products which is harmful to
the body
3. Regulation of
body temperature
4. Transports hormones from the organs which
produce them to the organs where they are needed.
Diseases and Disorders of human circulatory
system.
1.Thrombosis
•
Blood
clot forms inside vessel blades and stops flow of blood to tissue.
•
If it occurs in the coronary artery. It causes
coronary heart attacle. In the brain it leads to stroke
•
Arteriosclerosis:
This is the
hardening of arteries. They become less elastic forcing the heart to work
harder. It causes high blood pressure can lead to stroke or heart attacle
Control: Avoid smoking
-Reducing high cholesterol foods
in diet
-Avoid being high obese
- avoid stress, medication, Regular
exercise
2.Varicose Veins
Effects: Enlarged veins near surface of the skin. Their walls have lost their
elasticity and blood builds up inside them
Control measures:
·
Regular exercise
·
Supportive
stocking/stocks
Sickle cell Anaemia
This condition is a
genetic disorder which causes production of abnormal haemoglobin and
malformed red blood cells
Effects: Reduction of the bloods capacity to transport
oxygen.
Signs and symptoms
of sickle cell anaemia
- Fatique or excessive tiredness
- Shortness of breath during exercise
- Headaches
- Dark-coloured urine
- Abdominal pain
- Abnormal heart beat
- General body weakness
Treatment and
prevention of sickles anaemia
i It has no cure but patient can
ii. Avoid excessive physical exercise
iii.. Eat a well balanced diet that is rich of mineral vitamins.
i It has no cure but patient can
ii. Avoid excessive physical exercise
iii.. Eat a well balanced diet that is rich of mineral vitamins.
3.Leukemia
Leukemia is a cancer of the leucocyte- forming cells in the bone marrow
It is characterized
by proliferation of one or more of the white blood cells.
The excess white
blood cells infiltrate body organs
Eg. Liver and the
spleen
Sign and symptoms of leukemia
·
Abnormally
high number of white blood cells
·
Abnormal
bleeding eg, nose bleeding, easy bleeding even from minor cuts
·
Extreme
body weakness
·
Anemia
·
Throat
and mouth infections that may be securement
Treatment of Leukemia
- Frequent blood transfusions
- Radio therapy and chemotherapy to kill
the abnormal cells
- Bone marrow transplants
4.High Blood Pressure (Hypertension)
The blood pressure
of a normal human being is 120/80mm Hg
Too high blood
pressure is over 140/90mm Hg
Causes: High fat level, lack of exercise, obesity
High emotional
stress, alcoholism and smoking
Signs and symptoms -severe headache, ringing sound in the ear.
Prevention: Regular exercise, Balanced diet, Reduce stress
Pneumocystis
pneumonia- Lung infection causes by the fungus
5.Anaemia.
Is the lack of enough red blood cell haemoglobin in
the blood. It is common in places where malaria, hookworms and malnutrition are
common.
Causes.
-Excessive bleeding.
-Lack of iron or enough protein in the diet (no
enough haemoglobin form the bone marrow).
-Normal function of the bone marrow is destroyed by
disease or drugs.
-Abnormal bone marrow from birth, no enough normal
haemoglobin.
-Haemolysis, i.e. Red blood cells are destroyed more
quickly than the new ones are made. This can be due to disease like malaria.
6.Sickle cell anaemia.
Is a hereditary disease where one is born with
abnormal pigment of blood haemoglobin. The red cells assume a sickle-shape which reduces surface area
for transport of oxygen. Victims die before maturity.
Complications.
No enough haemoglobin in the blood to carry enough
oxygen to all parts of the body.
No part of the body works properly due to lack of
enough oxygen.
The heart pumps faster to try to get oxygen to all
parts of the body.
Muscles get tired and weak due to lack of enough
oxygen.
Dizziness and headache because the brain does not
get enough oxygen.
Paleness or whiteness of mucous membrane of the
mouth inside the lips and conjunctive under the lower eyelids.
Symptoms.
Weakness, tiredness, dizziness, shortness of breath.
Treatment:
Finding out the cause and getting rid of it. Blood
transfusion does not help the body to make more blood, or stop destruction of
red cells, or stop bleeding.
Prevention. Control of malaria, hookworm and use of
balanced diet.
*Sickle cell anaemia is an inherited
disease which has no treatment, and often cause death at an early age.
Filariasis or Elephantiasis.
Is caused
by filarial worms. The worms live in the lymphatic vessels and lymph nodes. The
worms cause inflammation and later block the flow of lymph through them causing
huge swellings. The disease occurs especially in tropical areas like coastal
areas of Africa, Asia and America
Adult filarial worm produces microfilaria which
develop in the mosquitoes and later pass to the people by bite.
Symptoms and signs.
Adult filarial worms irritate the lymph vessels and
lymph nodes in which they live. Acute attack causes inflammation of a limb,
joint, testes or swelling and tenderness of lymph nodes.
Heavy infestations lead to swelling of the legs,
scrotum, vulva, arms and breast. The nearby lymph nodes become large and hard.
The conditions is called Lymphodema.
The skin become thick and folded, hence name
elephantiasis.
Control and prevention.
Protection from mosquito bite; i.e. Use of
repellents, insecticides, nets at night, and protective clothing.
7.Haemophilia.
Is a hereditary sex-linked disorder that leads to
excessive bleeding due to failure of blood to clot following injury. Female
carriers are unaffected, where as males who inherit a defective allele exhibit
the disease.
Control: Administration of clotting factor.
Causes of Heart diseases.
Of all cases of high blood pressure (BP) only about
10% specific causes have been found.
*Atheroma (Arteriosclerosis) is the deposition of
fatty substances in the arteries which happen to every human being. It cause
hardening and loss of elasticity in the arteries. The deposit (atheroma)
increase with age. It can cause blood to clot and form a Thrombus (clot). This
cause heart attack from coronary thrombosis, that is if the clot blocks
coronary artery and the heart muscle does not get oxygen.
*Factors which cause heart disease are thought to
include:- smoking, fatty diet, stress, lack of exercises.
Low Blood Pressure or Hypotension.
Blood pressure below the normal level results from
heart defect or insufficient volume in the circulatory system. Causes of
decrease in blood volume can be malnutrition (no enough protein). Excessive
bleeding due to injury which may lead to shock. Low blood pressure can cause
failure of the pumping action of the heart and may lead to death. .
Symptoms of shock include: faint pulse, a rapid
pulse, pale and cool skin and dilated pupils. These are results of the body’s
attempt to restore normal pressure.
8..Coronary thrombosis
Occurs when there are blood clots in the blood vessels that supply blood to the heart(coronary arteries).This prevents blood from reaching some tissue of the heart.
Symptoms
-Uncofortable pressure or sharp pain in the chest
-Excessive sweating.
-Dizziness or fainting
-Nausea,
Shortness of breath
Effects
Can cause death of some cardiac muscles or sudden death
Prevention.s
-Doing regular exercise
-Avoid sudden strenuous activity
-Avoid alcohol and smoking
Avoid intake excessive fat
Treatment.
Using drug.
9.Stroke
Occur when there is interference in the amount of blood flowing to the brain.This can be due to blockage or rupture of artery supplying blood to the brain.
Symptoms
-Sudden numbness or weakness especially on one side of the body
-sudden confusion or troubl in understanding or speaking
-Sudden dizziness
Effects
-Paraysis on one side of the body, leading difficulties in movement and coordination
-lack of feeling on one side of the body, speech or language
Prevention
Avoiding drinking and smoking
- make sure your body pressure remains in the normal range
- Exercising regular
-eating low-fat, low-salt.
The
lymphatic system
Structure of the Lymphatic system
 |
| Fig Lymphatic system |
The tissue fluid which is not reabsorbed in
the bloodstream at the venule end of capillary enters another vessel called the
Lymphatic system.
Once
tissue fluid enters the lymph vessels It is called Lymph.
Lymph-Is pale-yellow fluid
is formed from tissue fluid that does not flow back into the capillaries.
Lymph-Is pale-yellow fluid
is formed from tissue fluid that does not flow back into the capillaries.
The lymph vessels join to form larger
lymphatic vessel which in turn join others to form the main duct called
lymphatic ducts.
There are main two.
Right lympatic duct- carry the lymph to the subclavian veins which bring blood back from the arms.
Left lympatic duct drains into the left subclavian vein
There are main two.
Right lympatic duct- carry the lymph to the subclavian veins which bring blood back from the arms.
Left lympatic duct drains into the left subclavian vein
At certain points the lymph vessels are
enlarged to form nodule- like structures. The structure is called lymph nodes
or lymph glands.
Lymph nodes or lymph glands are mainly
concentrated in the abdomen, neck, groin and armpits.
Lymph nodes contain a system of channels
through which the lymph flows.
Large numbers of white blood cells are
manufactured in lymph nodes.
Flow
of Lymph
The flown of lymph depend entirely on
mechanical squeezing of the lymph vessels by the contraction of the skeletal
muscle.
The flow of lymph towards the heart is
maintained by valves which are similarly in structure and function to those found
in the veins.
IMPORTANCE OF THE LYMPHATIC SYSTEM
1 Lymph node produce lympocytes(white blood cells) which help the body to fight diseases
2.Lacteals enable absorption of fatty acids after digestion
3.It provides a way of getting tissue fluid back to circulatory system
4.The spleen destroys worn out red blood cells
5.The spleen, the adenoid and the tonsils produce antibodies which help in fighting disea-causing microorganism
IMPORTANCE OF THE LYMPHATIC SYSTEM
1 Lymph node produce lympocytes(white blood cells) which help the body to fight diseases
2.Lacteals enable absorption of fatty acids after digestion
3.It provides a way of getting tissue fluid back to circulatory system
4.The spleen destroys worn out red blood cells
5.The spleen, the adenoid and the tonsils produce antibodies which help in fighting disea-causing microorganism
Disorders
of the lymphatic system
•
High blood pressure: An increase in blood pressure in the
capillaries results in the production of abnormally large quantities of lymph.
The lymphatic system may not be able to handle the increased lymph production
due to it may cause an oede
Blockage
of the lymph vessels
Elephatiasis
This is a disease that is caused by worms(Filaria) .that block the lymph vessels causing accumalation of lymph which leads to swelling of the arms or legs
Filaria are transmited by mosquitoes
This may occur to people who are infected by filarial worms, some of lymph vessels will be blocked by the parasites.
This may cause the legs or arms to become enlarged by oedema the condition is known as elephantiasis.
Elephatiasis
This is a disease that is caused by worms(Filaria) .that block the lymph vessels causing accumalation of lymph which leads to swelling of the arms or legs
Filaria are transmited by mosquitoes
This may occur to people who are infected by filarial worms, some of lymph vessels will be blocked by the parasites.
This may cause the legs or arms to become enlarged by oedema the condition is known as elephantiasis.
•
The treatment of this is done by destruction
and removal of the parasites
Oedema
Oedema
this is the swelling of the body tissues due to excessive lymph.It is caused by increased blood pressure in the capillaries, causing the production of large amount of lymph that the lymphatic system can not transport efficiently
Oedema can controlled by reduce blood pressure
Lyphoma
Is the cancer that affect the lymphatic system
-Resulting the weakening the immune system
Symptoms
Swollen andpainful lymphatic nodes
-fatique
-weight loss.
-Night sweating and itching
Treatment using chemotherapy and radiation therapy
Tonsillitis
This is infection and swelling of the tonsil-It caused by bacteria or viruses tat enter the body through mouth or sinuses
Symptoms
-Red and swollen of tonsils
-Sore throat,fever and chills
-Muscles ache and headache
Treatments
Mild tonsillitis are treated by having adequate rest and taking plenty of fluid
Severe tonsillitis is solved by tonsillectomy(surgical removing)
Oedema can controlled by reduce blood pressure
Lyphoma
Is the cancer that affect the lymphatic system
-Resulting the weakening the immune system
Symptoms
Swollen andpainful lymphatic nodes
-fatique
-weight loss.
-Night sweating and itching
Treatment using chemotherapy and radiation therapy
Tonsillitis
This is infection and swelling of the tonsil-It caused by bacteria or viruses tat enter the body through mouth or sinuses
Symptoms
-Red and swollen of tonsils
-Sore throat,fever and chills
-Muscles ache and headache
Treatments
Mild tonsillitis are treated by having adequate rest and taking plenty of fluid
Severe tonsillitis is solved by tonsillectomy(surgical removing)
Transport
of materials in plants
The vascular system of a plant is composed two
tissues which are xylem and phloem within the tissue there are transporting
cells called xylem vessels and xylem tracheids.
The transporting cells in the phloem tissue
are called phloem sieve tubes.
Xylem
Tissue Transports water
and mineral salts from the soil to all parts of the plants.
Phloem
Tissue Transports
manufacturer food from the site of photosynthesis to all parts of the plant in
between the xylem and phloem is cambium which divides to form new xylem and
phloem
have scattered vascular bundles (xylem and phloem) with no cambium
1.Xylem tissue,
transports water and mineral salts from the roots to the leaves. They are made
of xylem vessels and tracheids.
(a). Xylem vessels are very efficient in
transport of water and minerals. It consists of dead cells. These are long
hollow tubes mostly found in angiosperms. Lignin materials prevent them from
collapsing hence give support to the stem.
(b). Tracheids are modified xylem cells with
lignified pitted walls. Unlike xylem vessels, they have chisel-shape ends,
tapering cells. Are less efficient in conduction of water and minerals. They
offer support in gymnosperm and angiosperm. They conduct water and minerals in
pteridophytes.
*Phloem tissues, Is a
living tissue that transports manufactured food from the areas they are
produced (leaves) to the rest of the plant body. Is made up of sieve tubes and companion cells.
(a). Sieve tubes are elongated cells arranged
end to end. The cross walls are perforated, allowing flow of soluble materials
of photosynthesis from the leaves to other parts of the plant.
(b). Companion cells are on the side of sieve
tubes and are sites of high metabolic activity. They generate energy required
for translocation.
-Cambium: Vascular
cambium is a layer of the walled actively dividing cells between the xylem
and phloem. On the inner side it
forms the xylem and on the outer side it forms the phloem
.
-Vascular cambium does not occur in monocot stems,
so secondary growth does not take place in monocots like maize, sisal or palms.
The distribution of vascular bundles in plants
The way way the vascular bundles arranged in the roots, stem, and leaves of monocot, andDicots differ
1.Monocotyledonous roothave scattered vascular bundles (xylem and phloem) with no cambium
The arrangement and relative position of xylem
and phloem tissue in stems differ from those in roots.
2.In dicotyledonous root the phloem and xylem tissues are
separated cambium, the xylem tissue is on the inner side while phloem is on the
outer side.
The vascular bundles are arranged in a ring
with the stem. In monocot stems there is no cambium between the Xylem and
phloem tissues.
In roots: Xylem and phloem tissues are
arranged in separate units. In dicot the xylem tissue is arranged in the form
of star. The phloem alternates with the arms of the star.
monocotyledonous stem
Arrangement is random
Dicotyledonous stem
The vascular bundles are arranged around the central pith
The vascular bundles are arranged around the central pith
Function
of Xylem and Phloem.
•
A
continuous chain of xylem vessels transports water from the roots through the
stem to the leaves
•
Xylem
provides support to the plant.
•
It is
through phloem manufactured food is transported from the leaves to all parts of
the plant.
•
Transport
within the xylem is called conduction and is always upward through the plant.
Movement within the phloem is called
translocation and can be in any direction
.
.
The structure and its functions of root hairs
are extension of the epidermal cells of the root
are extension of the epidermal cells of the root
 |
| Fig.The structure of root hair |
•
Root
hairs are long and slender to provide a large surface area for the absorption of water and mineral salts from the soil.
•
The
large number of root hairs also increase
the total surface area of the roots
•
The root hair cell sap is usually hypertonic to the surrounding.
Hence, water enters the cell by osmosis.
•
Root
hair cells have a higher concentration of minerals than the surrounding mineral
salts are there for absorbed by active transportation.
•
The root
hairs are very thin in order to provide a short distance over which absorption
of water and mineral salts takes place.
Movement
of water and dissolved minerals salts
•
When
water is absorbed by the root hair, It dilutes the content of the cell sap vacuole as a result, the cell of the cortex, which are adjacent to the epidemis, have less water
than the root hair cells
•
Water moves from the root hair cells to the
cortex cells by osmosis. It moves the some way into the cells of the endodermis
then into the pericycle and then into the xylem.
•
One in
the xylem, the water and the mineral salts dissolved in it move up the xylem
vessels by transpirational pull, capillarity and root pressure.
1.Transpiration
Pull:
•
Transpiration occurs when water evaporates
from the plant through the stomach in the leaves. As water is lost the
mesophyll cells draw water from the xylem in the leaf which in turn draws water
from the xylem in the stem. This creates tension called transpiration pull
which draws water from the roots.
This results in a continuous column of water from the root, through the xylem to the leaves(transpiration stream)
This results in a continuous column of water from the root, through the xylem to the leaves(transpiration stream)
 |
| Transpiration pull |
2.Capillarity
Capillarity is the action that causes water to
rise in narrow tubes. Xylem vessels have a narrow lumen so it is possible for
water to rise in them by capillarity.
Capillarity is
made possible by cohesion and adhesion forces.
Cohesion is the
attraction between like molecules. It makes water molecules stick to each
other.
Adhesion is attraction between different
molecules. It causes water molecules to adhere to the xylem vessels.
Root pressure:
Root pressure pushes water and dissolved
mineral salts upward from the root. This happens because the cells of the
endodermis push mineral salts into the xylem.+
Transpiration:
Transpiration is the process by which plants
lose water to atmosphere through the stomata in the leaves. Water flows from the roots to the
leaves through xylem vessels. It enters the spongy mesophyll by osmosis.
Guttation also occurs in plant.
Guttation
is the process by which plant lose water as droplets through special
glands found where vein are in contact with leaf margin.
Transipiration differ from the Guttation is
such way that transpiration is the loss of water vapour mainly through the
plants stomata.
-Guttationoccur mostly at night or plant growing in wet areas
-Guttationoccur mostly at night or plant growing in wet areas
Guttation occurs mostly at night or in plants
growing in weat areas.
Types of transpiration.
•
Stomatal -occurs through the stomata on leaves
-It approximately about 90% of water lost
-It approximately about 90% of water lost
•
Curticular
occur through cuticle of leavesss of water
-Cuticle is a waxy layer that covers the surface of leaves and prevent excessive lo
-Cuticle is a waxy layer that covers the surface of leaves and prevent excessive lo
•
Lenticular
take place through the lenticels
-Lenticels are pores found on the back of the stem or root in the woody plant.
-Lenticels are pores found on the back of the stem or root in the woody plant.
Importance of Transpiration and the
transpiration stream
Transpiration is the loss of water from a plant by evaporation.
Water evaporates from the surface of mesophyll cells into the air
space within the leaf.
Factors are grouped into two
•
Environmental (external) factors
•
Structural
factors
Environmental Factors
•
Temperature:
rise in temperature result in high rate of transpiration because It
increase internal temperature of the leaf and leaves to increased evaporation
bringing about a cooling effect.
•
It
lowers relative humidity of the surrounding air increases ability of the
atmosphere to hold more water.
•
Humidity of the atmosphere
High humidity in the atmosphere lowers the concentration gradient of
water vapor between the atmosphere and leaf cells. This lowers the rate of water
loss low humidity results in a high water concentration gradient and more water
is lost through transpiration
•
Light
intensity
An increase in the intensity of light stimulates the opening of
stomata due to the uptake of water into guard cells. This allows a more rapid
rate of evaporation.
•
Air
currents
Strong air currents sweep away water vapour from the leaf surface.
This helps maintain a steep water gradient and hence increases the rate of
water loss from the leaf.
Low air currents result in accumulation of water vapour near leaf
surface. This lowers water gradient between stomata and atmosphere. This
reduces the rate of transpiration
•
Water
availability
Presence of water in the leaf enables the cell to be turgid; making
stomata remain open and hence more water is lost. Therefore, the rate of
transpiration is high when adequate water supply to the plant.
Little or unavailability of
water causes the stomatal pores to close
due to guard cells becoming fluid thus less water loss from the plant leaves.
Structure features.
This is biological conditions which regulate transpiration in plants.
They include:
a. Leaf surface
area:
Large leaves expose a large surface area over which water is lost.
Small leaves have a small surface area to allow transpiration hence low rate of
transpiration.
b. Stomata:
Large number of stomata on a given area of leaf results in high rate
of transpiration, because stomata provide site for evaporation.
c.Position of stomata: If they available on the upper surface of a
leaf, high rate of transpiration occurs than when they are present on the lower
leaf surface.
d.Large stomatal apertures: Enhance more water loss than stomata of small
apetures.
Importance/ significance
e. Cuticle:This is a waxy covering layer over a leaf
surface it affects water loss. Thick cuticlee greatly reduces water loss i.e the
rate of transpiration.
f.Epidermalhairs. This trap water on the surface of the leaves, thus preventing water loss
1.Brings about cooling of the plant, since it draws heat (latent heat of vaporization) to evaporate water being loss.
2.Enhances absorption and transportation of water and dissolved mineral salts from the soil to all parts of the plant.
3 Helps in removal of excess water. from the plant
4.It help to maintain the transpiration pull which is important for maintaining a constant stream of water between the roots and the leaves