4.3

Question 1

why is the heart divides into left and right sides

Answer 1

separate oxygenated and deox blood
-left side generates higher pressure for systematic circulation

Question 2

why there is a difference in thickness of atria and ventricles muscle

Answer 2

ventricles have to generate more pressure to pump all over body
-atria collect blood from body or lungs and pump it into ventricles

Question 3

compare the structure of aorta to pulmonary vein

Answer 3

aorta has thicker walls
-smaller lumen
more elastic tissue
-semi lunar valves

Question 4

why leaky atrioventricular valves find it hard to exercise

Answer 4

pressure rises in atrium during contraction of ventricle
-because blood flowing back into atrium
-lower pressure in aorta
-slower flow of oxygen to muscles
-less respiration in muscles

Question 5

how does smoking increase risk of blood clot formation from data

Answer 5

-increased smoking leads to more thrombin and fibrinogen
-no overlap in standard deviation
-thrombin converts fibrinogen to fibrin
-fibrin forms clots

Question 6

how time show in diagram relate to the cardiac cycle

Answer 6

-depolarisation starts at SAN pacemaker
-takes 0.03s to travel to AVN
-0.07s when atrial systole occurs
-delay at AVN
-0.16/0.17 at bundle of his
-0.17/0.22s at purkyne fibres
-ventricular systole ends at 0.22s
-atrioventricular valves open during atrial systole

Question 7

how atherosclerosis develops in arteries

Answer 7

damage to endothelium lining
-inflammatory response brings macrophages
-deposits of cholesterol/ calcium
-formation of atheroma

Question 8

compare frog heart to mammalian heart

Answer 8

-both have 2 atria
-both have atrioventricular valves
-frog has 3 chambers/ mammals 4

Question 9

describe sequence of stimulation that occurs in one cardiac cycle

Answer 9

-SAN acts as pace maker
-impulse travels through heart muscle
-AVN delays transmission of impulse to coordinate contraction of ventricle after atria
-impulse to purkyne fibres through His
-ventricles contract from apex

Question 10

how is tissue fluid formed

Answer 10

-high hydrostatic pressure forces fluid plasma out of the capillaries at the arteriole end

Question 11

how tissue fluid returned to capillaries

Answer 11

-more protein in plasma than in tissue fluid
-plasma proteins to large to pass out of capillaries
-oncotic pressure generated by plasma proteins
-fluid moves in as oncotic pressure greater than hydrostatic pressure

Question 12

compare transport of fluid in vein with transport in lymph vessel

Answer 12

-both have low pressure/ have valves/ use muscle for squeezing fluid out
-faster flow in vein
-heart causes mass flow movement in vein

Question 13

what happens to tissue fluid not reabsorbed into blood capillary

Answer 13

-tissue fluid enters lymphatic system
-lymph returns to subclavian veins