Control of Arterial Blood Pressure

Question 1

what is blood pressure?

Answer 1

the outwards hydrostatic pressure exerted by blood on the blood vessel walls

Question 2

what is systolic blood pressure?

Answer 2

the pressure exerted by blood when the heart contracts

Question 3

what is diastolic blood pressure?

Answer 3

the pressure exerted by blood when the heart relaxes

Question 4

what value is considered to be hypertension?

Answer 4

clinic BP over 140/90 AND daytime average of over 135/85

Question 5

what is pulse pressure?

Answer 5

the difference between systolic and diastolic blood pressures

Question 6

what is the normal range for pulse pressure?

Answer 6

between 30 and 50 mmHg

Question 7

what is the mean arterial blood pressure (MAP)?

Answer 7

the average arterial blood pressure during a single cardiac cycle

Question 8

how is MAP calculated?

Answer 8

MAP = (2diastolic + systolic)/3

OR

diastolic + 1/3pulse pressure

Question 9

what is the normal range for MAP?

Answer 9

70-105mmHg

Question 10

what is MAP of at least 60mmHg needed for?

Answer 10

to perfuse the coronary arteries, brain and kidneys

Question 11

what is MAP equal to?

Answer 11

cardiac output (CO) x systemic vascular resistance (SVR)

Question 12

what is the cardiac output?

Answer 12

the volume of blood pumped by each ventricle per minute

Question 13

how can cardiac output be calculated?

Answer 13

CO = stroke volume (SV) x heart rate (HR)

Question 14

what is stroke volume?

Answer 14

the volume of blood pumped by each ventricle of the heart per heart beat

Question 15

what is systemic vascular resistance?

Answer 15

the sum of the resistance of all the vasculature in the systemic circulation

Question 16

which vessel is the major resistance vessel?

Answer 16

the arterioles

Question 17

what is the baroreceptor reflex important for?

Answer 17

the moment-moment regulation of blood pressure, including prevention of postural changes

Question 18

what causes postural hypotension?

Answer 18

failure of the baroreceptor response to gravitational shifts in blood when standing up

Question 19

what is another name for postural hypotension?

Answer 19

orthostatic hypotension

Question 20

what indicates postural hypotension?

Answer 20

a drop in SBP of at least 20mmHg when standing with/without symptoms

OR

a drop in DBP of at least 10mmHg with symptoms

Question 21

what is total body fluid?

Answer 21

intracellular fluid + extracellular fluid (ECF)

Question 22

what is ECFV?

Answer 22

extracellular fluid volume

Question 23

what are the two main factors that affect ECFV?

Answer 23

water excess/deficit

sodium excess/deficit

Question 24

name three hormones/hormone systems that regulate ECFV

Answer 24

RAAS
natriuretic peptides (NPs) 
antidiuretic hormone (ADH)

Question 25

what does altering ECFV affect?

Answer 25

blood volume and blood pressure

Question 26

what does RAAS stand for?

Answer 26

the renin angiotensin aldosterone system

Question 27

what are the three main components of RAAS?

Answer 27

renin angiotensin aldosterone

Question 28

where is renin released from?

Answer 28

the kidneys

Question 29

what does renin do?

Answer 29

stimulates formation of angiotensin I from angiotensinogen in the blood

Question 30

what produces angiotensinogen?

Answer 30

the liver

Question 31

what happens to angiotensin I?

Answer 31

converted to angiotensin II by ACE

Question 32

what is ACE and where is it made?

Answer 32

angiotensin converting enzyme the pulmonary vascular endothelium

Question 33

what does angiotensin II do?

Answer 33

stimulates release of aldosterone causes vasoconstriction

Question 34

where is aldosterone released from?

Answer 34

the adrenal cortex

Question 35

what is aldosterone?

Answer 35

a steroid hormone

Question 36

what does aldosterone do?

Answer 36

acts on the kidneys to increase sodium and water retention

Question 37

what is the rate limiting step in RAAS?

Answer 37

renin secretion

Question 38

where is renin secreted from in the kidneys and what cells here release it?

Answer 38

the juxtaglomerular apparatus granular cells

Question 39

what are natriuretic peptides (NPs)?

Answer 39

peptide hormones synthesised by the brain and heart

Question 40

when are NPs released?

Answer 40

in response to cardiac distension or neurohormonal stimuli

Question 41

what do NPs cause?

Answer 41

excretion of salt and water in the kidneys decreases BP

Question 42

what is renin released in response to?

Answer 42

decreased blood pressure RAAS aims to increase it

Question 43

what are the two main types of NPs released by the heart?

Answer 43

atrial NP brain type NP

Question 44

what is another name for ADH?

Answer 44

vasopressin

Question 45

what is ADH?

Answer 45

a peptide hormone derived from a prehormone precursor, synthesised by the hypothalamus

Question 46

what stimulates secretion of ADH?

Answer 46

reduced ECVF | increased ECF osmolality

Question 47

what does ADH act on and what does it do?

Answer 47

the kidney tubules increases reabsorption of water

Question 48

what effect does ADH have on blood vessels?

Answer 48

causes vasoconstriction