transportation in human body

Question 1

erythrocytes (RBC)

Answer 1

biconcave, anucleate, diameter 7-8 um, development= 15 days, life span = 100 to 120 days

Question 2

functions of blood

Answer 2

-Blood produces interferon and antitoxins which are proteins and protects our body from nucleic acids of invading organism; and toxins of the invaders
-Blood helps the body in maintaining the internal environment, by producing, heparin,
histamines and also maintaining the amounts of chemicals in the body to a constant
or nearly constant level.

Question 3

Leucaemia (Blood Cancer):

Answer 3

It is the result of uncontrolled production of white blood cells (Leucocytes). This is cause by a cancerous mutation of a myelogenous or lymphogenous cell. The Leucaemia is usually characterized by greatly increased numbers of abnormal white blood cells in the circulating blood.
Myelogenous cells (bone marrow cells) are in the bone marrow and may spread
throughout the body so that white blood cells are produced in many other organs. These white blood cells are not completely differentiated and so arc detective. Leucaemia may be of different kinds depending on the type of white blood cells, which are undifferentiated and being produced at a faster, than normal rate. There may be
neutrophilic leucaemia, eosinophilic leucaemiaand basophilic leucaemia, monocytic or lymphocytic leucaemia. It is a very serious disorder and the patient needs to change the blood regularly with the
normal blood, got from donors. It can be cured by bone marrow transplant, which is in most cases effective but very expensive treatment.

Question 4

Thalassemia (G. Thalassa = Thesea; haema = blood)

Answer 4

It is also called Cooley’s anaemia on the name of Thomas B. Cooley American pediatrician.It is a genetically transmitted haemoglobin abnormality. Haemoglobin molecules in most cases, does not have β-chains in it instead F chain is present.
(F is foetal haemoglobin)
It is characterized by the presence of microcytes by spleenomegaly(enlargement of spleen) and by changes in the bones and skin.
This disease is more common in children especially of Mediterranean parents. The blood
of these patients is to be replaced regularly, with normal blood. It can be cured by bone marrow transplant - which is very expensive and does not give 100 % cure rate.

Question 5

Oedema:

Answer 5

It means the presence of excess fluid in the tissues of the body.The excess fluid may be in
the cells or outside the cells. The intracellular «edema is caused by osmosis of water into
the cells and cause, depression of metabolic systems (due to lack of nutrition and O2 in
the tissues) especially and the Na-pump.
The extracellular oedema may result by:
(i) Abnormal leakage of fluid from the blood capillaries or failure of the lymphatic system to
return fluid from the interstitial fluid.
(ii) Oedma is caused by renal retention of salts and water.
Oedema disturbs the exchange and concentration of minerals and ions ill the blood and body cells, it also affects blood pressure, increases heart load etc.

Question 6

Pericardium

Answer 6

The heart is enclosed in a double membranous sac - the pericardial cavity which contains the pericardial fluid. Pericardium protects the heart, prevents it from overextension.

Question 7

Wall of Heart:

Answer 7

The wail of the heart is composed of three layers. (i) I-picardium (ii) Myocardium (iii) Endocardium * Mycodium of the heart is made up of cardiac muscles. * These muscle contain myofibrils, and myofilaments of myosin and actin. * Their arrangement is similar to those in skeletal muscle fibres and their mechanism of contraction is also the same, except they are branched cells, in which the successive cells are separated by junctions called intercalated discs. * The heart contracts automatically within rhythmicity, due to the autonomic nervous system of the body.

Question 8

Chambers of Heart:

Answer 8

There are four chambers of the heart, two upper thin walled atria and two lower thick walled ventricles. Atria receive the blood and pass on to the ventricle which distribute the blood.

Question 9

Double Pump

Answer 9

Human heart functions as a double pump, and is responsible for pulmonary and systemic circulation. Complete separation of deoxygenated blood (Right side) and oxygenated blood (left side) in the heart is maintained.

Question 10

note

Answer 10

-Myocardium of the heart is made up of special type of muscles the cardiac muscles.
-In human heart: The right atrium receives deoxygenated blood via vena cava (inferior and
superior) from the body.
-Heartbeat involves three distinct stages:
(i) Diastole
(ii) Atrial systole
(iii) Ventricular systole.
One complete heart beat consists of one systole and one diastole, and lasts for about 0.8 seconds.
-The recording of heart beat is known as electrocardiogram which is taken by
electrocardiograph (E.C.G) machine.
-If there is some block in the flow of the electrical impulses, or if the impulses initiated by S.A, node are weak; it may lead to death of the individual. So an artificial pacemaker which is
battery operated producing electrical stimulus is used.
-The pressure within capillaries causes a continuous leakage of fluid from the blood plasma
into the spaces that surround the capillaries and tissues, This fluid is interstitial fluid, It has
water in which are dissolved nutrients, Hormones, gases, wastes and small proteins from the
blood.
-Large proteins. red blood cells and platelets cannot go to the intercellular spaces of, capillary

Question 11

Atherosclerosis

Answer 11

• Atheroma + arteriosclerosis = Atherosclerosis

-Atherosclerosis causes narrowing and hardening of arteries.

Question 12

systole and diastole

Answer 12

The pressure reaching its high point during systole (systolic pressure which in normal
individuals is 120 mm Hg) and its low point during diastole (diastolic pressure which in normal
individuals ranges between 75-85 mm Hg).

Question 13

heart attack or
technically myocardial infarction

Answer 13

Blockage of blood vessel in the heart by an embolus (or by locally formed thrombus) causes
necrosis or damage to portion of the heart muscles. a condition known as a heart attack or
technically myocardial infarction

Question 14

stroke or cerebral infarction.

Answer 14

If the normal flow of blood is blocked by an embolus (or a locally formed thrombus), in a
blood vessel in the brain, and causes necrosis, or death, of the surrounding neural tissue
(owing to lack of O2) the condition is called a stroke or cerebral infarction.

Question 15

Haemorrhage

Answer 15

Haemorrhage is the discharge of blood from blood vessels

Question 16

humoral
immune response

Answer 16

B-cells recognize antigen and form plasma cell clone. These plasma cells synthesize and
liberate antibodies into the blood plasma and tissue fluid. Here antibodies attach to the
surfaces of bacteria and speed up their phagocytosis, or combine with and neutralize
toxins produced by micro-organisms by producing antitoxins. This is called humoral
immune response.

Question 17

antibody molecule

Answer 17

An antibody molecule consists of four polypeptide chains, two identical light chains and two identical heave chain - linked by disulfide (- S - S -) bridges. Variable amino acid Sequences (V) in the light chains and upper regions of the heave chains determine which antigen will bind to that particular antibody constant amino acid sequences (e) are the same for all the antibodies in one class (b) large antigen-antibody complexes will form if there are multiple copies of the antigenic molecule on the foreign cell’s surface.

Question 18

Active Immunity

Answer 18

Active Immunity results when exposure to a disease organism triggers the immune system to produce antibodies to that disease. Active immunity can be acquired through natural immunity or vaccine-induced immunity
{For example, an individual who recovers from a first case of the measles is immune to further infection}
- natural = infection
- artificial = vaccination

Question 19

Passive Immunity

Answer 19

Passive immunity is provided when a person is given antibodies to a disease rather than producing them through his or her own immune system. A newborn baby acquires passive immunity from its mother through the placenta.
- natural = meternal antibodies ( from mother)
-artificial = monoclonal antibodies

Question 20

AIDS

Answer 20

In AIDS the affected suffer deficiency in the immune system of the body. This is because that the Viruses live in the Helper T-lymphocytes.

Question 21

immunization

Answer 21

-The medical practice of immunization began at the end of the eighteenth century, when English physician Edward Jenner (1749-1823) successfully vaccinated 23 people against small pox. Jenner called his method “vaccination,” using the Latin words vacca, meaning “cow” and vaccinia, meaning “cowpox” Because the two diseases are caused by similar viruses that have the same antigens, antibodies that work against cowpox will also fight smallpox.
-In 1885 a rabies vaccine developed by French scientist Louis Pasteur (1822-1895) from the spinal fluid of infected rabbits proved to be successful, since that time, vaccines have been developed for many diseases including diphtheria, polio, pertussis (whooping cough), measles, mumps, rubella (German measles), hepatitis and influenza.
-Vaccines are made from either weakened live or killed microorganisms. When introduced into the body they stimulate the production of antibodies providing active immunity against bacterial and viral diseases.

Question 22

antigens

Answer 22

a toxin or other foreign substance which induces an immune response in the body, especially the production of antibodies.

Question 23

antibodies

Answer 23

A protein made by plasma cells (a type of white blood cell) in response to an antigen ,Each antibody can bind to only one specific antigen. The purpose of this binding is to help destroy the antigen.