Session 5 - Blood Pressure

Question 1

what is mean atrial blood pressure equal to

Answer 1

cardiac output x total peripheral resistance

1/3 pulse pressure + diastolic pressure

Question 2

what is cardiac output equal to

Answer 2

stroke volume x heart rate

Question 3

what is pulse pressure equal to

Answer 3

systolic - diastolic

Question 4

what is the short term regulation of blood pressure

Answer 4

the baroreceptor reflex were the amount of sympathetic and parasympathetic input to the heart is altered

Question 5

where are the baroreceptors located

Answer 5

carotid sinus and aortic branch

Question 6

how do baroreceptors detect an increase in blood pressure

Answer 6

they stretch due to increased arterial pressure

Question 7

where do baroreceptors send signals to

Answer 7

the cardiovascular centre in the medulla oblongata

Question 8

true or false: baroreceptors control short and long term changes in blood pressure

Answer 8

false - if there is sustained blood pressure than the threshold for baroreceptors increases

Question 9

what responds for long term control of blood pressure

Answer 9

neurohumoral response

Question 10

what are the neurohumoral responses directed at controlling

Answer 10

sodium balance and extracellular fluid volume

Question 11

what are the 4 neurohumeral pathways to control blood pressure

Answer 11

1. renin-angiotensin-aldosterone system
2. sympathetic nervous system
3. antidiuretic hormone (ADH)
4. atrial natriuretic peptide (ANP)

Question 12

where is renin released from

Answer 12

granular cells of the juxtaglomerular apparatus

Question 13

what factors stimulate renin release

Answer 13

1. reduced salt delivery to distal tubule
2. reduced perfusion of kidneys
3. sympathetic stimulation of JGA

Question 14

how is a reduced perfusion of the kidneys detected

Answer 14

by baroreceptors in the afferent ateriole

Question 15

what cells in the kidney detect the salt delivery

Answer 15

macula densa cells

Question 16

what makes up the juxtaglomerular apparatus

Answer 16

macula densa + granule cells +surrounding cells

Question 17

outline the renin-angiotensin-aldosterone system

Answer 17

• renin causes the conversion of angiotensinogen to angiotensin I
• ACE enzymes convert angiotensin I to angiotensin II

Question 18

what does ACE stand for

Answer 18

angiotensin converting enzyme

Question 19

what does angiotensin II do

Answer 19

• causes vasoconstriction
• releases aldosterone from the adrenal cortex
• causes sodium reabsorption in the kidney (directly and indirectly through aldosterone)

Question 20

what are the 2 main angiotensin II receptors and what type of receptors are they

Answer 20

AT1 (main) and AT2

GPCRs

Question 21

how does angiotensin II alter the sympathetic nervous system

Answer 21

it causes an increase in noradrenaline release

Question 22

what does angiotensin II do to the hypothalamus

Answer 22

increases thirst sensation so stimulates ADH release

Question 23

what are the actions of aldosterone

Answer 23

• acts on principal cells of the collecting duct to stimulat Na and water reabsorption

Question 24

what channels does aldosterone activate

Answer 24

• apical Na channels (ENaC)
• apical K channels
• increases activity of Na/K/ATPase

Question 25

why do ACE inhibitors cause a build up of bradykinin

Answer 25

bradykinin is broken down into peptide fragments by ACE enzymes

Question 26

what effect does bradykinin have

Answer 26

vasodilator effects

Question 27

give an example of an ACE inhibitor

Answer 27

captopril

Question 28

what side effect does a build up of bradykinin cause

Answer 28

dry cough

Question 29

how does the sympathetic nervous system control blood pressure

Answer 29

- high levels of sympathetic activation reduce renal blood flow decreasing Na excretion - activation of Na channels so theres more reabsorption - stimulates renin release from JG cells

Question 30

what is the role of antidiuretic hormone

Answer 30

increases water and Na reabsorption forming concentrated urine

Question 31

what stimulates ADH release

Answer 31

- plasma osmolarity | - severe hypovolaemia

Question 32

what is hypovolaemia

Answer 32

decrease in the volume of blood in your body

Question 33

what are the actions of ANPs

Answer 33

- vasodilation of afferent ateriole giving increased blood flow to kidneys - inhibits Na reabsorption

Question 34

where are ANPs released

Answer 34

atrial myocytes

Question 35

what causes the release of ANP

Answer 35

atria stretching due to high blood pressure

Question 36

what is natruresis

Answer 36

loss of sodium in the urine

Question 37

what are prostaglandins

Answer 37

vasodilators which act locally do enhance glomerular filtration and reduce Na reabsorption

Question 38

how does dopamine affect blood pressure

Answer 38

causes vasodilation, reduced NaCl absorption and increased renal blood flow

Question 39

what is hypertension

Answer 39

sustained increase in blood pressure seen over repeated readings

Question 40

what are the stages of hypertension

Answer 40

1 - over 140/80 mmHg 2 - over 160/100 mmHg 3. - over 180 systolic or 110 diastolic

Question 41

what is accelerated hypertension

Answer 41

where a significant rise in blood pressure rapidly can cause damage to the vessels

Question 42

what causes hypertension

Answer 42

- 95% is unknown or multifactorial (primary hypertension) | - remainder is where the cause can be defined (secondary hypertension)

Question 43

what is renovascular disease

Answer 43

where there is an occlusion of the renal artery causing a fall in perfusion pressure in that kidney leading to increased renin production which increases blood pressure

Question 44

what does renal parenchymal disease cause

Answer 44

loss of vasodilator substances and retention of Na and water

Question 45

what happens to the appearance of the kidneys in renal parenchymal disease

Answer 45

they get smaller

Question 46

what is Conn's syndrome

Answer 46

aldosterone secreting adenomas

Question 47

what happens in Cushing's syndrome

Answer 47

there is an excess of glucocorticoid cortisol which acts on aldosterone receptors

Question 48

what is a phaeochromocytoma

Answer 48

a tumour of the adrenal gland which secretes catacholamines

Question 49

what are the symptoms of high blood pressure

Answer 49

none - but if severe it can give headaches

Question 50

what types of diseases occur due to hypertension

Answer 50

vascular diseases

Question 51

what organs should be assessed with someone with hypertension

Answer 51

brain, eyes, heart, kidneys and arteries

Question 52

how does hypertension damage arteries

Answer 52

- causes atherosclerosis due to fat deposition and stiffness | - weakens vessels

Question 53

how does hypertension affect the heart

Answer 53

the increased pressure causes left ventricular hypertrophy leading to heart failure and theres an increased oxygen demand by the heart leading to myocardial ischemia and MI

Question 54

what are the non-pharmacological approaches to treating hypertension

Answer 54

- diet - exercise - reduced Na intake - reduced alcohol

Question 55

what drugs help reduce blood pressure

Answer 55

- ACE inhibitors - L type calcium channels blockers - beta blockers - alpha blockers - diruretics

Question 56

how do calcium blockers reduce hypertension

Answer 56

reduce calcium entry to smooth muscle cells so they relax

Question 57

what do alpha 1 blockers do

Answer 57

reduce sympathetic tone causing relaxation of smooth muscle