control of blood pressure

Question 1

define blood pressure

Answer 1

pressure exerted by blood upon walls of vessel

Question 2

why is blood pressure important

Answer 2

to maintain flow of blood in vessels

Question 3

what is the equation for blood pressure

Answer 3

bp= cardiac output x systemic vascular resistance

Question 4

what is systemic resistance

Answer 4

resistance in the circulatory system that is used to create blood pressure, the flow of blood

Question 5

whats the equation for cardiac output

Answer 5

cardiac output = heart rate x stroke volume

Question 6

what do you use to measure blood pressures

Answer 6

sphygomomanometer
(band wrapped around arm with meter attached, pump at the end and pump applies pressure to band. depending on the sounds hear the meter tilts towards diastolic or systolic side)

Question 7

whats the typical stroke volume

Answer 7

70 mls

Question 8

typical heart rate

Answer 8

70bpm

Question 9

what is a pulse

Answer 9

rhythmic expansion and contraction of artery made by waves of pressure caused by ejection of blood from left ventricle of heart as it contract

Question 10

where are the 4 places pulse can be measured

Answer 10

carotid
radial
femoral
dorsalis pedis

Question 11

what are the 3 things that control you blood pressure/ keep it stable

Answer 11

baroreflex
adrenaline
RAAS renin-angiotensin-aldosterone system

Question 12

how does the bare reflex control bp

Answer 12

• stretch receptors in aorta carotid since send signals to brainstem

-this stimulate or depress the sympathetic nervous system

• when stimulated local noradrenaline released
• this increase stroke volume by increasing cardiac contractions or
• increase heart rate via actions on SA/AV node or
• contract blood vessels

OR

signals are sent to stimulate/depress parasympathetic nervous system where it acts upon heart rate by releasing acetyl choline

Question 13

how does adrenaline control BP

Answer 13

the adrenal medulla increases the AD concentration in sympathetic nerve endings

Question 14

what is postural hypotension

Answer 14

a drop in blood pressure when you stand up after lying or sitting down. This can make you feel dizzy and can even cause you to faint. You might: feel lightheaded or dizzy when you stand.

Question 15

how does RAAN control bp

Answer 15

It regulates your blood pressure by increasing sodium (salt) reabsorption, water reabsorption (retention) and vascular tone (the degree to which your blood vessels constrict, or narrow).

Aldosterone also causes water to be reabsorbed along with sodium; this increases blood volume and therefore blood pressure.

Question 16

what does ANP AND BNP stand for

Answer 16

atrial naturetic peptide
brain naturetic peptide
secreted by atria and ventricles respectively

Question 17

how does ANP and bnp lower bp

Answer 17

• they’re released in response to atrial and ventricular distension
• both stimulate the excretion of sodium (naturesis) and therefore water
• this lowers blood volume and hence blood pressure

Question 18

HIGH levels of BNP in blood can be used as part of diagnostic workup for heart failure

Question 19

what negative affect can adrenaline and noradrenaline induce

Answer 19

can induce venocontriction which has the effect of squeezing blood in the venous circulation back to the heart

liberating some of the blood that is effectively ‘stored’ in the venous circulation

Question 20

what does LVEDV stand for

Answer 20

left ventricular end diastolic volume

Question 21

what is the frank-starling curve and what does it show

Answer 21

the normal relationship between the length and tension of the myocardium.

The greater the stretch on the myocardium before systole (preload), the stronger the ventricular contraction.

Question 22

what are the difference in structure of artery and veins

Answer 22

artery:
- thick muscular walls
- narrow lumen
- not readily collapsible (withstands high pressure)
- dont have valves

veins:
- thin muscular walls
- wide lumen
- easily collapsible
- have valves