UNIT# 09
TRANSPORT
Q. Define
Transport and its types.
In biology, transport refers
to the act or the means by which a molecule or ion is moved across
the cell membrane or via the bloodstream.
There
are two types of transport in this regard:
·
Passive transport and
·
Active transport
PASSIVE TRANSPORT
Passive transport requires
no energy. It occurs when substances move from areas of higher to lower
concentration. Types of passive transport include simple
diffusion, osmosis, and facilitated diffusion
ACTIVE TRANSPORT
Active
transport is the movement of molecules across a cell membrane from a
region of lower concentration to a region of higher concentration—against the
concentration gradient. Active transport requires cellular energy to
achieve this movement.
Q. Describe
the structure of Root.
STRUCTURE OF ROOT
Externally, root has a root tip which is covered by root cap.
The remaining part of root is highly branched and each branch is heavily
covered by root hairs. Each root hair is a fine tubular outgrowth of an
epidermal cell. It grows between soil particles which remains in close contact
with the soil solution surrounding them.
Internally, the T.S. of root shows that root is mainly consist
of:
·
Epidermis (Epiblema) the
outer layer of cells, some of these cells have root hair.
·
The Cortex part of root
between epidermis and endodermis, consist of number of cellular layers.
Q. Describe the role of
Roots in transport of water and minerals.
The root absorb water and minerals from soil through root
hairs.
There are two processes of transport:
a.
Passive
transport
The uptake of water and mineral by osmosis and diffusion
without using energy of ATP. It is due to concentration gradient i.e. always
takes place from high to low quantity of substances.
b.
Active
transport
Movement of substances from low quantity to high quantity i.e.
against the gradient and it requires energy of ATP. This movement is called
active transport.
·
Uptake of
Water from Soil
The root hair increases the surface area which increases the
rate of absorption of water and minerals. The cell membrane prevents the cell
sap from leaking out. The cell sap has low tendency of water loss than the
solution of soil which result in water movement from soil to root hair. This
process of water movement from a solution of high water potential to a solution
of low water potential is called Osmosis. In this way, water may pass from cell
to cell and finally forced into xylem and ascend up to the aerial part of
plant. This upward movement of water with mineral is called ascent of sap.
·
Mineral
transport
Plant also require minerals i.e. nitrates, sulphates,
phosphates etc. These minerals are also taken up by root hair in two ways:
(a) By diffusion, when the concentration of certain ions in
soil is higher than that in root hair cells i.e. passive transport.
(b) By active transport, plant requires some substance even
they found in soil in low quantity. The roots have to absorb these ions against
a concentration gradient by using energy of ATP, which is active transport.
Q. What is
Transpiration?
TRANSPIRATION
The loss of internal water of plant in the form of vapours
from aerial part of plant is called transpiration
Q. Describe the types
of leaves on the basis of stomatal distribution.
TYPES OF LEAVES ON THE BASIS OF STOMATAL DISTRIBUTION
Plants have three types of leaves on the basis of stomatal
distribution:
·
Leaves that have stomata
at lower epidermis called bifacial leaves e.g. leaves of mango plant.
·
Leaves that have stomata
at both surfaces (upper and lower epidermis) called monofacial leaves e.g.
leaves of maze plant.
·
Leaves that have stomata
at upper epidermis only e.g. leaves of water lily.
Q. Describe the
mechanism of opening and closing of stomata.
MECHANISM OF OPENING AND CLOSING OF STOMATA
Stomata are the pores usually found in the leaf epidermis
surrounded by two kidney shaped guard cells which contain chloroplast. The
guard cells control the opening and closing of stomata.
The inner wall of guard cells is thick and inelastic whereas
the outer wall is thin, elastic and permeable. The changes in the turgidity of
guard cells controls the opening and closing of stomata.
Stomata open when the guard cell become turgid and close when
the guard cells become flaccid. The turgidity of guard cell is regulated by
concentration of solutes present in it which mainly depends upon the rate of
photosynthesis. The stomata remain open during the sunny day, as a result rate
of transpiration increases. But at night they are closed, hence transpiration
also stops.
Q. Describe
the significance of Transpiration.
SIGNIFICANCE OF TRANSPIRATION
·
By active transpiration, transpiration
pull is created which helps in the ascent of sap.
·
Transpiration also
increases the rate of absorption because the loss at one end increases demand
on other end.
·
Transpiration gets rid of
the excess amount of water from plant.
·
Transpiration helps in
maintaining the temperature of plant for its metabolism and survival because
evaporation causes cooling.
·
Opening and closing of
stomata is also regulated by transpiration
Q. Describe the factors
affecting on transpiration.
FACTORS AFFECTING ON TRANSPIRATION
The rate of transpiration is affected by some of the following
environmental factors.
I.
Temperature:
Rate
of evaporation of water from cell surface increases with increase in
temperature.
II.
Humidity:
The
rate of transpiration decrease with the increase in water vapors in atmosphere
i.e. humidity.
III.
Wind: The
increase in wind velocity increases the rate of transpiration. The wind
decreases the water vapors around plant and make the atmosphere dry.
IV.
Atmospheric
Pressure: Low atmospheric pressure increases the rate of
transpiration through reduction in the density of air.
Q. Describe
the transport of water and food in stem.
TRANSPORT OF WATER AND FOOD IN STEM
The vessels or tissues which transport water, minerals and
food in the flowering plants are called vascular tissues. There are two types
of transport tissues in plants.
·
Xylem
·
Phloem
XYLEM
Xylem is made up of four type of tissues but the main tissues
are the xylem vessels.
A xylem vessel is a long, hollow, tubular structure from root
to leaf. It is made up of many dead cells arranged vertically. The walls of
these vessels become strong by the deposition of chemical substance called
lignin. The tube reduces the resistance of water flowing through the xylem. It
gives faster passage to sap, as a result transpiration pull is created in leaf.
The thick, rigid and lignified walls of vessels also provides mechanical
support which strengthen the wall.
PHLOEM (BAST)
Like xylem, phloem is also made up of four type of tissues but
mainly consist of sieve tubes and companion cells. The sieve tubes or sieve
tube elements of phloem is made up of columns of elongated and thin walled
living cells. A mature sieve tube cell has only a thin layer of cytoplasm
inside the cell. This cytoplasm is connected to cells above and below through
sieve plates. Each sieve tube cell has a companion cell beside it, which carries
out the metabolic processes need to keep the sieve tube cells alive. Companion
cells provide nutrients and help the sieve tube cells to transport manufactured
food.
CONDUCTION OF FOOD
In contrast to sieve tube cell, the companion cells have many mitochondria
to provide energy needed for the companion cells to load sugar from mesophyll
cell to sieve tube cells by active transport. The perforations of sieve plates
allow rapid flow of manufactured food substance through the sieve tube.
TRANSPORT OF FOOD
The movement of organic materials (food) take place through
phloem. Along with food, phloem also conducts other substances such as
vitamins, hormones etc. The movement of prepared food from leaves to different
parts of plant through phloem elements (sieve-tubes) is called translocation
According to Much hypothesis, solutes are translocated through
the sieve tubes which flow in bulk from the supply end i.e. source (leaves) to
the consumption end i.e. sink (root) under a turgor pressure gradient. As a result
of photosynthesis, the supply ends (leaves) have a large amount of organic
solutes, which causes tremendous increase in suction pressure of leaf cells
(Mesophyll cells) and they draw water from the xylem of the leaf. As a
consequence their turgor pressure is increased. The turgor pressure in the
cells of stem and root is comparatively low and hence, the soluble organic
solutes begin to flow in mass from mesophyll through sieve-tubes down to the
cells of stem and root under the gradient of turgor pressure. These solutes are
either consumed or stored in insoluble form. The excess water is released back
into the xylem vessels.
TRANSPORT
IN ANIMALS
Q. What is
circulatory system? Name types of circulatory system. Describe each.
CIRCULATORY SYSTEM
The system involved in the transport of various substances
within the body of an animal is called Circulatory System. The circulatory
system transports gases like O2, CO2 etc. nutrients,
wastes, hormones and defense proteins.
There are two types of Blood Circulatory Systems found in
animals
·
Open circulatory system
·
Closed circulatory system
OPEN CIRCULTORY SYSTEM
In this type of Circulatory System blood flows through the
spaces among tissue so it directly comes in contact with tissues. It remains
filled in the open tissue spaces called Sinuses. After exchange of materials
with tissues, blood enters the pumping organs or heart which pumps it into
blood vessels.
These vessels again drain out blood into sinuses so it remains
in Circulation.
This type of circulatory system found in arthropods and
molluscs.
CLOSE CIRCULATORY SYSTEM
This type of system allows blood to flow inside the closed
tubular blood vessels and never comes out in direct contact with tissues.
Q. Name the
components of Circulatory system in Man.
COMPONENTS OF CIRCULATORY SYSTEM
In man, closed type of circulatory system is found, which
consists of following components.
·
Blood: A fluid with cells
and other dissolved substances.
·
Heart: A pumping,
pulsatile organ.
·
Blood vessels: Tubes i.e.
Arteries, veins and capillaries.
Q. Write is Blood?
BLOOD
Blood is a special type of tissue, found in the form of fluid,
circulates in the body. It transports substances in the body of an organism.
It consists of two parts: (i) Plasma (ii) Corpuscles
Q. Write
note on Plasma.
PLASMA
Plasma is the fluid part of blood and constitutes about 55% by
volume of whole blood.
About 90% of plasma is water in which complex mixture of
various substances are dissolved.
·
There are dissolved
mineral salts like bicarbonates, sulphates, chlorides and phosphates of sodium
(Na) and potassium (K).
·
Salts of calcium are
present for clotting of blood.
·
Soluble proteins i.e.
Serum albumin, Serum globulin, fibrinogen and prothrombin are present.
·
Antibodies are present
which are involved in fighting diseases.
·
Plasma contains digested
food substances such as glucose, amino acids, fatty acids and vitamins.
·
It also contains excretory
products such as Urea, Uric acid and creatinine.
·
Carbon dioxide (CO2)
is also present as bicarbonate ions.
·
It also contains hormones.
Q. Write
note on Erythrocytes.
ERYTHROCYTES OR RED BLOOD CORPUSCLES
RBCs are biconcave, circular disc like structure. Mature RBCs
are anucleated (no nucleus) while the immature RBCs may have nucleus. The
normal life span of RBCs is 120 days.
RBCs are produced in the bone marrow after 120 days, their
destruction occurs in Spleen and liver
RBCs are responsible to transport oxygen and carbon dioxide
gases.
Q. Write
note on Leucocytes.
LEUCOCYTES
Leucocytes are also called White blood cells. They are colorless,
irregular in shape, nucleated and lager sized cell than R.B.Cs.
They protect the body by killing germs that enter the body
that is why they are called the ‘police of the body’.
There are several types of White blood cells which perform
different functions.
|
Types
of WBCs |
Description |
Average
number |
Function
|
|
Granulocytes |
|||
|
Neutrophils
|
About
twice the size of RBCs, nucleus 2 to 5 lobed |
62% |
Destroys
small particles by Phagocytosis |
|
Eosinophils
|
Bi-lobed
Nucleus |
2% |
Inactivates
inflammation producing substances, attack parasite |
|
Basophils |
Bi-lobed
Nucleus |
1% |
Release
heparin to prevent blood clots and histamine which causes inflammation |
|
Agranulocytes |
|||
|
Monocytes |
3 to 4
times larger than RBCs, nuclear shape from round to lobed |
3% |
Macrophages,
destroys large particles by phagocytosis |
|
Lymphocytes
|
Slightly
larger than RBCs, nucleus nearly occupies cell |
32% |
Immune
response by producing antibodies |
Q. Write
note on Platelets.
PLATELETS
Platelets are the fragments of cells which are formed from
large precursor cells in the bone marrow. On injury, the platelets at injury
site start to produce an enzyme in blood. This enzyme causes the fibrinogen to
form insoluble fiber of fibrin which forms a network of fibers around wound
which protects blood to flow and stops the entry of pathogen.
Q. Describe
the blood disorders.
BLOOD DISORDERS
LEUKEMIA
It is a type of cancer that affects the blood, bone marrow and
lymphatic system.
In this type of blood cancer, number of W.B.Cs increases and
R.B.Cs decreases.
SYMPTOMS
o
Fever or chill
o
Persistent fatigue
o
Weakness
o
Frequent or severe
infections
o
Loss of weight without try
o
Swollen lymph node
o
Enlarge liver or spleen
o
Easy bleeding or bruising
o
Recurrent nose bleeding
o
Ting red spots on skin
o
Sweating at night
o
Bone pain or tenderness
CAUSES
o
Mutations in blood DNA
o
Genetic disorder
o
Exposure to certain
chemicals
o
Smoking
o
Family history
THALASSEMIA
This condition is characterized as insufficient or inability
of producing hemoglobin.
SYMPTOMS
o
A pale and restless
appearance
o
Poor appetite
o
Slowed growth and delayed
puberty
o
Dark urine
o
An enlarged spleen, liver
or heart
o
Jaundice
THALASSEMIA MAJOR
It occurs when a child inherits two mutated genes, one from
each parent. Children born with this disorder lack the ability to produce
normal, hemoglobin and feel chronic fatigue.
THALASSEMIA MINOR
Thalassemia minor have occurred when a child inherit it from
one of the parent. Persons have mild anemia and slight lowering of hemoglobin
level in the blood. It resembles with mild iron deficiency anemia. People with
this disorder do not have any symptoms.
Q. Explain
the structure of Heart.
HEART
Heart is the major organ of Circulatory system. It is located
in the thorax slightly at the left side and is enclosed in Pericardium.
It is conical in shape externally. The space between
pericardium and heart is pericardial cavity which is filled with pericardial
fluid.
Internally, it consists of four chambers, the upper two are
thin walled called atria and the lower two are thick walled called ventricles.
Atria are completely separated from each other by interatrial septum.
Similarly, the two ventricles are also separated from each other by inter-ventricle
septum. Each atrium is connected with its ventricle by an auriculo-ventricular
aperture. The right atrium and right ventricle are connected by Tricuspid
Valve. Similarly, left atrium and left ventricle are connected by bicuspid
valve. These valves prevent the backward flow of blood. Two main blood vessels
arises from ventricles to carry blood from heart to all parts of the body.
Q. Explain
the function of Heart.
FUNCTION OF HEART
The circulation of blood in our body is called double circuit
system because it circulates blood in two separate circuits. These two circuits
are:
i.
Pulmonary
Circuit; from heart to lungs and back from lungs to heart.
ii.
Systemic
Circuit; from heart to different organs and from organs
back to heart.
PULMONARY CIRCUIT
It transports blood from right ventricle to lungs through
pulmonary arteries and flow back to heart in left atrium through pulmonary
veins.
The deoxygenated blood from all over the body except lungs
received in right atrium and then collected into right ventricle, upon
contraction of ventricle this deoxygenated blood enters into pulmonary arch
which supply this blood to the lungs, where blood gives up its CO2
and receives O2 from air. The deoxygenated blood now becomes
oxygenated which flow back to the left atrium through pulmonary veins. This
oxygenated blood now circulates through the body by Systemic circuit.
SYSTEMIC CIRCUIT
Circulation of oxygenated blood from left ventricle through
systemic aorta to all organs of body and back to heart by superior and inferior
vena cava as deoxygenated blood is called systemic circuit.
Upon contraction the left ventricle forces oxygenated blood
into systemic aorta, the largest artery of our body. Initially, the aorta gives
off three branches which supply blood to head, arms and shoulders. This aorta
then descends down and gives off many branches which supply blood to their
respective organs e.g. a branch which supplies blood to liver called Hepatic
artery, another branch called renal artery supplies blood to the kidney and
coronary artery to heart etc.
The oxygenated blood converts into deoxygenated blood as cell
and tissues add CO2 in it. Now it enters into the right atria so
pulmonary circuit begins.
Q. What is
heart beat?
HEART BEAT
The pumping of blood by the rhythmic pulsation of heart
throughout the body is called heartbeat.
Q. What is
mean by systole and diastole?
SYSTOLE
The contraction of heart muscle and pumping the blood from the
chambers into the arteries named as systole.
DIASTOLE
The phase of heart beat of the relaxation of heart muscle and
allowing the chambers to fill with blood is called diastole.
Q. What is
heart rate?
HEART RATE
Heart rate can be define as the number of heartbeats in a
minute.
On average, a healthy heart beats 72 times in a minute. The
normal range of heart rate is 60 – 100 beats in a minute.
Q. What is
Brady cardia?
BRADYCARDIA
This condition is characterized as abnormally slow heart rate
(or below 50 beats per minute) due to very slow heartbeat.
This slow heart rate reduces amount of blood and oxygen to
vital organs of body, and causes shortness of breath, dropping of blood
pressure, extreme fatigue etc.
Q. What is
tachycardia?
TACHYCARDIA
This condition is characterized as abnormally high heart rate
(more than 100 beats per minute), this condition is called tachycardia.
The tachycardia is caused by the fever, dehydration, excessive
caffeine or a reaction to medication.
Symptoms includes:
o
Chest pain
o
Dizziness and fainting
Effects of tachycardia can be:
o
Sudden cardiac arrest
o
Heart failure
o
Weaken heart muscle
o
Lung diseases
Q. Describe
the types of blood vessels.
TYPES OF BLOOD VESSELS
There are three types of blood vessels, which are;
(i)
Arteries,
(ii)
Veins and
(iii)
Capillaries
Q. Write
note on arteries.
ARTERIES
Those blood vessels which carry blood away from the heart are
called arteries.
Right ventricle of heart pumps blood into the pulmonary artery
that goes to the lungs.
The wall of Arteries consists of three layers,
·
The inner most layer,
which is made up of epithelial tissues.
·
The middle layer consists
mostly of smooth muscle and elastic fibers.
·
The outer wall is made up
of flexible connective tissue.
Because of layered structure arteries have both strength and
flexibility. The walls of arteries are generally thick and they have thin
lumen.
(Pulmonary artery is the only artery which contains
deoxygenated blood)
Q. Write
note on Veins.
VEINS
Those blood vessels which carry deoxygenated blood from body
towards the heart are called veins.
The walls of veins have three layers with muscle in the middle
layer. However, the walls of vein are generally thinner than those of arteries.
They have large lumen.
(Pulmonary vein is the only vein which contains Oxygenated
blood)
Q. Write
note on Capillaries.
CAPILLARIES
These are the microscopic blood vessels found in the cells of
tissues.
They have walls made up of single layer of flattened cells
called endothelium. They are originated from arterioles and branches repeatedly
to provide large surface area for the exchange of substances between the blood
and the tissue cells.
Q. Describe
the role of Ibn-al-Nafees and William Harvey in the field of circulation.
IBN-AL-NAFEES
Ibn-al-Nafees was the first Arab Physician to explain
pulmonary circulation.
He believed that all the blood that reached the left ventricle
passed through the lungs.
WILLIAM HARVEY
William Harvey was an English Physician to explain systemic
circulation in detail. He believed that blood being pumped to the brain and
body by the heart.
Q. What is
CVD?
CVD
CVD stands for cardiovascular disorders. It is related to
cardiovascular system i.e. heart and blood vessels.
Q. What is
Atherosclerosis and arteriosclerosis?
ATHEROSCLEROSIS (ATH)
ATH is a disorder in which bad fats (i.e. low density
lipoprotein or LDL and cholesterol) get deposited in blood vessels internal
layer.
Accumulation of fats leads to gradual narrowing of lumen of
blood vessel which leads to compromise of blood supply to target organs, and
leads to myocardial infarction and stroke.
ARTERIOSCLEROSIS
It is a process in which arteries loss their elasticity due to
some pathological process (e.g. ATH) or simply by aging. Loss of elasticity
leads to high blood pressure which may eventually be able to lead to vascular
hemorrhage.
Q. What are
the causes of Myocardial infarction?
CAUSES OF MYOCARDIAL INFARCTION
Causes of myocardial infarction can be divided into
non-modifiable factors (which we cannot change) and modifiable factors (which
we can change).
|
Non-modifiable factors |
Modifiable factors |
|
Sex (More
in males) |
Stationary
life (no exercise) |
|
Age ( More
in old age) |
Smoking |
|
Race (More
in blacks) |
Stress |
|
Family
history |
Heavy
alcohol consumption |
|
|
High fat
diet |
Q. What is
mean by Vascular Surgery?
VASCULAR SURGERY
Vascular surgery is a prominent field of surgery in which
vessels i.e. arteries, veins and lymphatic vessels are managed by vascular
surgeons. Field gained very prominence when surgery involves bypass surgeries
of heart, angioplasty, and fistula formation in cases of renal failure.
