human transport !!

Question 1

pulmonary circulation !

Answer 1

transports blood between the heart and the lungs

• pulmonary ateries : heart -> lungs
• pulmonary veins : lungs -> heart

Question 2

systemic circulation !

Answer 2

transports blood between the heart and the other parts of the body
oxygenated blood : left side of heart -> arteries -> rest of the body
deoxygenated blood : rest of body -> veins -> right side of heart

Question 3

advantages of double circulation !

Answer 3

blood enters pulmonary circulation (lungs) at a lower pressure than blood leaving the heart
- ensures that blood flows slowly through the lungs -> allowing sufficient time for blood to be fully oxygenated before returning to heart

blood is pumped into the systemic circulation (rest of the body) at high pressure
- allows for oxygenated blood to be distributed to body tissues more quickly -> maintain high metabolic rate in mammals

Question 4

chambers of heart !

Answer 4

atria : thinner walls compared to ventricles
- force blood into ventricles : short distance -> lesser pressure needed

left ventricle thickest : pumps blood to rest of the body
- longer distance -> more pressure needed

right ventricle less thicker : ensures that rate of blood flow is lower
- sufficient time for gaseous exchange to take place in the lungs

Question 5

medium septum !

Answer 5

muscular wall dividing left and right sides of heart

- ensure oxygenated and deoxygenated blood to mix -> ensures there’s efficient transport of oxygen

Question 6

movement of blood !

Answer 6

rest of the body -> vena cava -> right atrium -> tricuspid valve -> right ventricle -> semilunar valve -> pulmonary arch -> pulmonary artery -> lungs -> pulmonary vein -> left atrium -> bicuspid valve -> left ventricle -> semilunar valve -> aortic arch -> aorta -> rest of the body

Question 7

ventricular systole !

Answer 7

ventricles : contract
atria : relax

• increase in ventricular pressure causes tricuspid + bicuspid valve to close -> lub

Question 8

ventricular diastole !

Answer 8

ventricles : relax

- decrease ventricular pressure -> closure of semilunar valves -> dub sound

Question 9

atery !

Answer 9

carries blood away from heart

small lumen + thick elastic muscular walls to withstand the high pressure exerted by heart

Question 10

vein !

Answer 10

carries blood towards the heart
large lumen + thinner elastic muscular walls : carry blood at lower pressures
contains semilunar valves to prevent backflow of blood with lower pressure

Question 11

capillary !

Answer 11

allows exchange of gases, nutrients + waste materials between the blood & cells
one cell thick -> shorter diffusion distance -> allow faster rate of diffusion

Question 12

blood !

Answer 12

55% - plasma

45% - WBC, RBC, platelets

Question 13

plasma !

Answer 13

90% - water
hormones : insulin
soluble proteins : fibrinogen, prothrombin, albumin, globulin, antibodies
food substances : glucose, amino acids, fats, vitamins
excretory products : urea, uric acid, creatinine, bicarbonate ions (CO2)
dissolved mineral salts : hydrogencarbonates, chlorides, sulfates, phosphates of Ca K NA

Question 14

RBC / erythrocytes

Answer 14

produced in bone marrow, destroyed in spleen

limited life span of 120 days (3-4 months) -> due to lack of nucleus which is responsible for reproduction

Question 15

RBC features/adaptations

Answer 15

1. contains haemoglobin : combines reversibly with oxygen to form oxyhaemoglobin
   - enabling RBC to transport O2 from lungs to all parts of body
2. circular, flattened biconcave shape : increases surface area to volume ratio
   - increasing rate of diffusion of O2
3. absence of nucleus : have more space
   - can contain more haemoglobin
4. elastic, can turn bell-shaped : allows RBC to squeeze through blood vessels
   - efficient transport of O2 to all parts of body

Question 16

WBC / lenocytes

Answer 16

produced in bone marrow, destroyed in spleen
limited lifespan of a few days : involved in fighting against bacteria & viruses
- phacocytes
- lymphocytes

Question 17

phagocytes

Answer 17

• engulf and destroy foreign particles by phagocytosis

lobed nucleus
granular cytoplasm

Question 18

lymphocytes

Answer 18

produce antibodies to destroy foreign particles causing them to agglutinate -> easier for phagocytosis by phagocytes to take place
- easier to neutralise toxins produced by foreign particles

large rounded nucleus
small amt of non-granular cytoplasm
round in shape
limited movements

Question 19

platelets / thrombocytes

Answer 19

formed from fragments of cells found in blood

- helps clots blood

Question 20

blood groups !

Answer 20

plasma : contains natural antibodies which recognise and bind to antigens on RBC

agglutination / clumping of RBC : occurs when antibodies react with antigens on RBC

Question 21

group A

Answer 21

antigen A

antibody b

Question 22

group B

Answer 22

antigen B

antibody a

Question 23

group O

Answer 23

universal donor
no antigen
antibodies a & b

Question 24

group AB

Answer 24

universal acceptor
antigens A & B
no antibody

Question 25

atherosclerosis !

Answer 25

condition whereby fatty substances build up in coronary arteries
- narrows lumen

Question 26

effects of coronary heart disease !

Answer 26

heart attack : occurs when blood flow to a particular part of the heart is blocked

• lumen of atery becomes narrower as blood clot forms in atery -> reduced blood flow to heart -> heart muscle receives reduced O2 supply
• insufficient O2 and glucose

angina : chest pain

Question 27

causes of coronary heart disease !

Answer 27

1. diet high in saturated fats & cholesterol
   - increases fatty deposits forming on the inner walls of the coronary arteries

2, smoking : contains nicotine & carbon monoxide

• nicotine : causes the release of adrenaline -> increases heart rate + blood pressure
• carbon monoxide : damages lining of inner walls of coronary arteries + increases the formation of fatty deposits on the inner walls + blood clots that get trapped within the damaged arteries

3. stress : increases release of adrenaline
   - increases heart rate + blood pressure
4. high blood pressure : damages lining of inner walls of coronary arteries + increases formation of fatty deposits and blood clots

Question 28

preventive measures !

Answer 28

1. healthy diet : low saturated fats + cholesterol
2. avoid smoking
3. manage stress
4. exercise regularly

Question 29

clotting of blood !

Answer 29

when blood vessels : damaged
- damaged tissues + blood platelets : release enzyme thrombokinase

prothrombin in plasma -> thrombin by thrombokinase, in presence of calcium ions

thrombin : catalysts concentration of soluble protein fibrinogen -> insoluble fibrin threads
- entangle blood cells to form a clot -> sealing the wound -> preventing entry of microorganisms & loss of more blood

Question 30

phagocytosis !

Answer 30

phagocytes engulf & destroy foreign particles

dead cells combine with dead bacteria to form pus

Question 31

antibodies !

Answer 31

bind to bacteria : ruptures bacterial surface membrane
- causes bacteria to bind together : agglutination -> can be easily engulfed by phagocytosis

neutralists harmful substances (toxins) produced by bacteria