Body Fluid Homeostasis

Question 1

Name some hormones involved with body fluid homeostasis

Answer 1

vasopressin, aldosterone, renin angiotensin

Question 2

What is vasopressin

Answer 2

anti-diuretic hormone

Question 3

What releases vasopressin

Answer 3

posterior pituitary gland

Question 4

What releases vasopressin into the capillaries

Answer 4

neuro-secretory neurons in the hypothalamus

Question 5

What is the function of vasopressin

Answer 5

regulate body fluid osmolality, conserve water

Question 6

Describe the relationship between body fluid osmolality and vasopressin

Answer 6

if body fluid osmolality increases - vasopressin release increases

Question 7

Where are hypothalamic osmoreceptors located

Answer 7

supra-optic and paraventricular nuclei of hypothalamus

Question 8

What stimulates hypothalamic osmoreceptors

Answer 8

increase in osmolality

Question 9

What does activation of the hypothalamic osmoreceptors cause

Answer 9

generation of AP in neuro-secretory neurons - vasopressin release

Question 10

What causes increased release of vasopressin

Answer 10

increased osmolality plasma, solute ingestion, water deficiency, MDMA

Question 11

What causes decreased release of vasopressin

Answer 11

decreased osmolality plasma, excessive fluid ingestion, alcohol

Question 12

What channels does vasopressin act on

Answer 12

AQP2

Question 13

What is the effect of vasopressin

Answer 13

fall in body fluid osmolality, increased reabsorption of water

Question 14

What is the main symptom of diabetes insipidus

Answer 14

large amounts of dilute urine produced

Question 15

What is the cause of central diabetes insipidus

Answer 15

dont release vasopressin

Question 16

Where is the defect in central diabetes insipidus

Answer 16

neuro-secretory neurons - dont function properly

Question 17

How is central diabetes insipidus treated

Answer 17

nasal spray containing vasopressin

Question 18

What is the cause of nephrogenic diabetes insipidus

Answer 18

no response to vasopressin

Question 19

Where is the defect in nephrogenic diabetes insipidus

Answer 19

defect in V2 receptor or mutations in gene for AQP2

Question 20

What releases aldosterone

Answer 20

outer layer zona glomerulosa of adrenal gland

Question 21

What is aldosterone

Answer 21

mineralocorticoid

Question 22

What is the function of aldosterone

Answer 22

regulates mineral content of the body

Question 23

What is aldosterone released in response to

Answer 23

rise in plasma potassium, decrease in ECF volume

Question 24

What does aldosterone act on

Answer 24

distal tubule, collecting duct - principal and alpha cells

Question 25

What is the effect of aldosterone

Answer 25

increases reabsorption of sodium and water, increased secretion of potassium and hydrogen

Question 26

TRUE or FALSE - Aldosterone is membrane permeable as its a steroid

Answer 26

TRUE

Question 27

What does aldosterone bind to

Answer 27

cytosolic receptor

Question 28

What does aldosterone stimulate

Answer 28

synthesis of ENaC

Question 29

What is the difference in the way vasopressin and aldosterone work

Answer 29

vasopressin - non genomic, aldosterone - genomic

Question 30

What does aldosterone increase

Answer 30

H+ and K+ secretion

Question 31

Which hormone has the slower response - vasopressin or aldosterone

Answer 31

aldosterone

Question 32

What is the NET effect of aldosterone

Answer 32

decrease plasma K+ and H+, increase ECF volume

Question 33

Why do Liddle's patients exhibit hypertension

Answer 33

high rate of Na+ reabsorption across principal cells

Question 34

What is suppressed in Liddle's syndrome

Answer 34

aldosterone release

Question 35

What are the characteristics of pseudohypoaldosteronism

Answer 35

lost ability to respond to aldosterone

Question 36

What does the renin-angiotensin system regulate

Answer 36

body fluid volume, plasma Na+, plasma K+

Question 37

Where is renin released from

Answer 37

juxtaglomerular apparatus

Question 38

What do macula densa cells monitor

Answer 38

changes in tubular fluid

Question 39

What do macula densa cells send signalling molecules to

Answer 39

afferent arteriole

Question 40

What stimulates the release of renin

Answer 40

sympathetic nervous system

Question 41

What is the source of renin

Answer 41

kidney

Question 42

What does angiotensin II cause

Answer 42

release of aldosterone, vasoconstriction, increased BP, increased plasma sodium

Question 43

What do ACE inhibitors cause

Answer 43

vasodilation, reduction of aldosterone

Question 44

What is the NET effect of vasopressin increase

Answer 44

increased water reabsorption and ECFV, decreased osmolality,

Question 45

What is the NET effect of a decrease in aldosterone

Answer 45

increased water and sodium loss, decreased ECFV