cardiovascular system

Question 1

need for a circulatory system??

Answer 1

evolutionary, increase in size and complexity so simple diffusion is not adequate to supply system with nutrients and to remove the waste. provides a steep concentration gradient

Question 2

Roles of circulatory system ?

Answer 2

primary role: distribution of dissolved gases for nutrition and growth and repair

also: chemical signalling dissipation of heat, mediation of inflammatory response

Question 3

types of capillary bed>

Answer 3

single bed e.g. coronary capillaries
to beds in parallel e.g. splenic and mesenteric capillary beds join before portal hepatic
two beds in series e.g. glomerular and peritubular at kidneys

Question 4

blood pressure measuring

Answer 4

measured as a pressure between 2 points

using a sphygmomanometer that reports the arterial pressure in millimetres of mercury

Question 5

Total cardiac output =

Answer 5

stroke volume x heart rate

Question 6

blood flow?

Answer 6

greater the pressure difference between 2 points the greater the flow
blood flows from high tho low pressure

Question 7

resistance depends on?

Answer 7

viscosity of blood
size of lumen
length of the vessel

Question 8

what causes BP to vary?

Answer 8

how far away from heart ventricle
systemic of pulmonary circuit
systole or diastole

Question 9

hydrostatic pressure?

Answer 9

pressure exerted by a liquid in response to an applied force

Question 10

pressures in the systemic circuit?

Answer 10

at left ventricle in systole = 130 mmHg

arterioles = 80mmHg

Question 11

pressures in the pulmonary circuit?

Answer 11

right ventricle in systole = 30 mmHg

arterioles = 20 mmHg

Question 12

what is systolic and diastolic pressure ?

Answer 12

systolic = ventricular systole 
diastolic = diastole

Question 13

pulse pressure meaning?

Answer 13

difference between systolic and diastolic pressure

Question 14

what is a pulse?

Answer 14

rhythmic pressure oscillation that accompanies Heart beat

Question 15

What effects systolic pressure ?

Answer 15

ejection velocity 
stroke volume (output during a single beat from either L or R ventricle)

Question 16

What effects diastolic pressure?

Answer 16

total peripheral resistance and blood flow from arterial to venous sides

Question 17

korotkoff sounds?

Answer 17

hear when taking BP
loud sound = turbulent flow
silence = laminar flow

Question 18

mean arterial pressure calculation =

Answer 18

diastolic BP + 1/3 of (systolic BP - Diastolic BP)

Question 19

disruption in homeostasis of BP and volume could be due to ….

Answer 19

trauma
increase temp
chemical changes - CO2 O2 NO
pH

Question 20

endocrine response to adjust low BP

Answer 20

Aldosterone produced by the adrenal glads that sit able the kidneys - Na+ retention which causes water retention and K+ loss. therefore more h20 in blood increasing volume and pressure

Angiotensin 2 hormone (8 amino acids) -

1. target is the blood vessel (rapid response) causing vasoconstriction of smooth muscle increasing resistance and therefore increasing arterial pressure.
2. target is the kidney, slower response, sodium reabsorption occurs so water follows. Stroke volume increases
3. pituitary gland effect: releases ADH (antidiuretic) so water reabsorption so bp increase

Question 21

Baroreceptors role in BP

Answer 21

detect stretching of the blood vessel walls in the carotid sinus in carotid artery. negative feedback loop.

BP high - stimulate baros, cardioinhibitory stimulated, cardioacceleratory inhibited, vasomotor inhibited, vasodilation and lowering of cardiac output

BP low - stimulates vasomotor centre, stimulate cardioacceleratory centre, inhibits cardioinhibitory centre, vasoconstriction and increase cardiac output

Question 22

what are the cardioinhibitry and accelerator centres ?

Answer 22

inhibitory = increases parasympathetic 
accelerator = increases sympathetic

Question 23

What is the vasomotor centre?

Answer 23

controls activity of the sympathetic neurone that inert the vascular smooth muscle

Question 24

what is orthostasis?

Answer 24

suddenly standing from lying or sitting - causes increase in vascular tone

Question 25

hypertension? what is it?

Answer 25

BP is more than 140/90

Question 26

What are ACE inhibitors?

Answer 26

angiotensin converting enzyme inhibitor which disrupts the renin- angiotensin-aldosterone system an example = ramipril When the body recognises there is a drop in the pressure of the blood flowing to the kidneys it causes a substance called renin to be released. This promotes the production of angiotensin I. The angiotensin converting enzyme then acts to convert the angiotensin I to produce the hormone angiotensin II. Angiotensin II causes: constriction of the smooth muscles surrounding blood vessels in the body and promotes the production of a hormone called aldosterone. increase the reabsorption of sodium and water. tightening of the blood vessels and the increase in fluid volume in the body causes an increase in the blood pressure

Question 27

Thiazide diuretics?

Answer 27

reduce blood volume y causing more water to be lost in urine

Question 28

metoprolol used for?

Answer 28

to decrease cardiac output - sympathetic b1 adrenoreceptor antagonist

Question 29

3 layers of the blood vessel?

Answer 29

tunica interna (intima) = endothelial cells resting on a basement memrane Tunica Media - smooth muscle and elastic fibres - elastin covered by microfibrils Tunica Externa - collagen fibres and elastic fibres, vasa vasorum (network of small blood vessels) , nerves

Question 30

metarterioles?

Answer 30

terminal regions of arterioles?

Question 31

precapillary sphincter -

Answer 31

monitors blood flow into the capillary

Question 32

autonomic NS regulated capillary contraction and dilation how?

Answer 32

vasoconstriction - noradrenaline activate a1 adrenoreceptors (G couples Gq subunit that activates phospholipase C, activates IP3 causing the release of calcium) Vasodilation - reduced release of noradrenaline

Question 33

3 types of capillary?

Answer 33

continuous = have inter endothelial junctions 10-15nm wide and have coated pits for leaking products fenstrated - fenestra allow large molecules to pass, found in areas with high molecular exchange. Fenestra are covered by a thin diaphragm Sinusoidal (discontinuous) = large gaps

Question 34

difference in capillaries in the blood brain barrier -

Answer 34

have tight junctions and so molecules have to be transported by transporter so no adverse neuronal effect

Question 35

Types of vein?

Answer 35

post capillary venules - porous, site for exchange muscular venules- thin muscle layer can expand, are reservoirs for blood Vena Cava = valves, more muscular than smaller veins

Question 36

What is the lymphatic system?

Answer 36

excess fluid and proteins enter forming lymph and are filtered and returned to blood when needed 3 roles - 1 drain excess interstitial fluid maintaining blood vol 2 transport dietary lipids 3 carries out immune responses

Question 37

what makes up the lymphatic sysytem?

Answer 37

lymph nodes - remove foreign substances by filtering lymphatic vessels - some smooth muscle, have valves to prevent back flow Lymphatic capillaries - more leaky than blood capillaries and have inter endothelial junctions called primary lymph valves