physiology of blood pressure

Question 1

what is mean systemic arterial (MAP) pressure the product of

Answer 1

cardiac output (CO) and total peripheral resistance (TPR)

MAP=COxTPR

Question 2

what does autonomic control influence (BP related)

Answer 2

cardiac output and vascular resistance

Question 3

what does long term response in kidney influence BP related

Answer 3

vascular resistance

Question 4

what is the fundamental role of the kidney

Answer 4

• filtration
• reabsorption
• excretion

Question 5

what is glomerular filtration rate

Answer 5

a test that estimates how much blood passes through the glomeruli each minute (how well the kidneys work)

Question 6

what are the three basic renal processes

Answer 6

• glomerular filtration
• tubular reabsorption
• tubular secretion

Question 7

is GFR usually high or low

Answer 7

very high, around 180L/day

means there’s lots of opportunity to regulate EFC composition and get rid of unwanted substances

Question 8

is it the EFC that is regulated or the urine

Answer 8

the EFC

Question 9

do kidneys have good or bad blood supply

Answer 9

really good

0.5% total body weight but 20% of CO

Question 10

what does GFR regulate

Answer 10

hormonal release

Question 11

what does the macula densa do

Answer 11

senses GFR by Na+

Question 12

what does the juxtaglomerular (JG) apparatus include

Answer 12

JG cells that secrete renin

Question 13

what are the most important hormones involved in the control of BP

Answer 13

• antidiuretic hormone (vasopressin)
• angiotensin II
• aldosterone
• atrial natriuretic peptide (ANP)

Question 14

what is the principal facto controlling Ang II levels

Answer 14

renin release

Question 15

how does decreased circulating Ang II volume stimulate renin release

Answer 15

through

• decreased BP
• decreased NaCl at macula densa
• decreased renal perfusion pressure

Question 16

important actions of angiotensin II

Answer 16

• stimulation of aldosterone release from adrenal cortex
• vasoconstriction of renal and other systemic vessels
• enhanced tubuloglomerular feedback (makes macula densa more sensitive)
• enhance Na-H exchanger and Na channel to promote Na reabsorption
• renal hypertrophy
• stimulates thirst and ADH release by acting upon hypothalamus

Question 17

what does aldosterone stimulate

Answer 17

Na reabsorption and K excretion by the renal tube

Question 18

what does aldosterone exert

Answer 18

indirect negative feedback on RAAS by increasing ECV and by lowering plasma (K)

Question 19

what is aldosterone really important for

Answer 19

conserving Na and water

preventing massive swings in K levels

Question 20

what is the primary importance in blood pressure (kidneys)

Answer 20

RAAS

Question 21

what activates RAAS

Answer 21

reduced blood flow

Question 22

what causes loss of control of blood pressure (kidneys)

Answer 22

• renal disease
• renovascular disease
• any decrease in kidney blood flow (GFR)
• inappropriate activation of RAAS

Question 23

what does angiotensin II cause

Answer 23

• direct constriction of renal arterioles
• stimulation of aldosterone synthesis

Question 24

what does deceased pressure in renal arterioles and sympathetic activity cause

Answer 24

renin production which causes angiotensin II production

Question 25

what does reduction in renal pressure cause

Answer 25

intrarenal redistribution of pressure and increased absorption of salt and water