cardiac physiology

Question 1

Sinusoids

Answer 1

have large intercellular clefts that llow protein and blood cells to pass through the cells

Question 2

Transcytosis

Answer 2

mainly for large lipid-insoluble materials, they get endocytosed, then exocytosed

Question 3

hydrostatic pressure is due to

Answer 3

pressure water in blood plasma exerts AGAINST BLOOD VESSEL WALLS
its about 35 mmHg of mercury at the arterial end of the capillary and 16 mmHg at the venous end
IFHP is always about 0mmHg

Question 4

Why dosen’t the interstitial osmotic pressur change much

Answer 4

because the small amount of protein that leaks from blood plasma cells do not accumulate there because it passes into lymph in lympathic capillaries, which is eventually how it returns to blood

Question 5

What is the main factor that allows Frank Starling’s law of capillaries

Answer 5

the decrease in hydrostatic blood pressure

Question 6

Difference between blood flow and blood velocity

Answer 6

It is the volume of blood that flows through any tissue in a given time period,

different from the blood velocity, which is the speed at which blood flows

Question 7

Systolic blood pressure would be

Answer 7

The highest pressure in arteries during systole

Question 8

Diastolic blood pressure

Answer 8

The lowest arterial pressure due to ventricular relaxation

Question 9

Mean arterial pressure formula

Answer 9

Diastolic blood pressure+1/3( systolic blood pressure- diastolic blood pressure)

Question 10

Total peripheral resistance

Answer 10

Blood vessel length-hypertension because of additional blood vessels in their adipose tissue increase their total blood vessel length
Blood viscosity-due to dehydration/polycythemia

Most of the resistance comes from physical contact with the walls of the blood vessels

Question 11

what happens when you have an incompetent tricuspid valve

Answer 11

some of the blood goes out from ventricles, and the pressure in atria goes up, this causes a decrease in venous return caused by pressure differences

Question 12

Skeletal and Lung Muscle pump

Answer 12

The compression of the pump is called milking,

Similarly when the diapragm expands the squeezed abdominal veins eter into the depressed thoracic veins

Question 13

Chemoreceptor reflexes

Answer 13

part of the nervous regulation of blood pressure,
These are found in a similar place to carotid bodies and aortic bodies, and are resposible for the CV centre to increase blood pressure and beating

and getting the respiritory system for more breathing

Question 14

Hypovolemic shock

Answer 14

when blood volume falls, kidneys secrete renin into the bloodstream,

Renin produces angiotensin, which is a potent vasoconstrictor but also helps produce aldosterone, which helps resabsorb sodium and water into kidneys

Question 15

Epinephrine and Norepinephrine

Answer 15

force of contraction, and causes vasoconstriction of arterioles and veins in skin and abdominal organs

Question 16

ADH

Answer 16

causes vasoconstriction and reabsorption of water into the kidney so there will be more water in bloodstream causing increased hydrostatic force

Question 17

ADH

Answer 17

causes vasoconstriction and reabsorption of water into the kidney so there will be more water in bloodstream causing increased hydrostatic force

Triggered by increase in osmolarity of tissue fluid and volume,
should be released at a hypervolemic state or increased osmolarity of tissue fluid

Question 18

Inotropic drugs

Answer 18

found in the interstitial fluid, this causes calcium from the interstitital fluid to flow into the myocardium, depolarising it causing contraction

Question 19

parasympathetic hormones

Answer 19

Nitrous oxide, and Acetylcholine

Question 20

Frank Starling’s law of the heart

Answer 20

states that stroke volume increases as end diastolic volume increases

This because as there is an increase in the volume of blood entering the heart during diastole, the ventricular myocytes are stretched