Regulation of ECF volume

Question 1

What are the major ECF osmoses which dictate fluid movement?

Answer 1

Na & Cl

Question 2

What % of the body is composed of water?

Answer 2

60% (42L)

Question 3

In TBW, what does ICF make up?

Answer 3

2/3

28L

Question 4

In TBW, what is the volume of plasma?

Answer 4

3L

Question 5

What composes the ECF?

Answer 5

Interstitial fluid

Plasma

Question 6

What is the volume of ECF?

Answer 6

14L (1/3)

Question 7

What volume does the interstitial fluid compose?

Answer 7

11L

Question 8

In what circumstances can high volumes of water be lost?

Answer 8

Vomiting
Diarrhoea
Excess sweating

Question 9

A decrease in plasma volume resulting in a reduction in ____ to the heart.

Answer 9

Venous return

Question 10

A reduction in venous return will result in a reduction in ___, ____ &____

Answer 10

SV
CO
BP

Question 11

A drop is BP will be detected by which baroreceptors?

Answer 11

Carotid sinus baroreceptors

Question 12

When the baroreceptors detect a drop in BP, what happens?

Answer 12

Sympathetic discharge

Question 13

What does sympathetic activity do to the vasculature?

Answer 13

Increases TPR

Increases BP

Question 14

What is released from the pituitary in response to hypovolaemia?

Answer 14

ADH

Question 15

What does sympathetic activity do at the kidneys?

Answer 15

Increased renal arteriole constriction

Renin secretion

Question 16

What does renin convert angiotensinogen to?

Answer 16

Angiotensin I

Question 17

What converts Angiotensin I to Angiotensin II?

Answer 17

ACE

Question 18

What effect does angiotensin II have at the peritubular capillaries?

Answer 18

Increases Na reabsorption at proximal tubule

Question 19

What does angiotensin II stimulate the secretion of from the adrenal cortex?

Answer 19

Aldosterone

Question 20

Where does aldosterone mediate its action?

Answer 20

Distal tubule

Question 21

What maintains GFR?

Answer 21

Autoregulation

Question 22

Where is the majority of water/ Na reabsorbed?

Answer 22

Proximal tubule

Question 23

What is responsible for the constriction of afferent renal arterioles?

Answer 23

Sympathetic innervation

Question 24

What is responsible for the constriction of efferent renal arterioles?

Answer 24

Angiotensin II

Question 25

What is responsible for the control of Na reabsorption at the distal tubule?

Answer 25

Aldosterone

Question 26

What type of hormone is Aldosterone?

Answer 26

Adrenal cortical steroid hormone

Question 27

What mediates the release of aldosterone?

Answer 27

Kidneys

Question 28

Where are the juxtaglomerular cells (JG) found?

Answer 28

In the afferent arteriole, just before the glomerulus

Question 29

What is the specialised loop of the distal tubule called?

Answer 29

Macula densa

Question 30

What forms the juxtaglomerular apparatus?

Answer 30

Juxtaglomerular cells | Macula densa

Question 31

What cells produce the hormone renin?

Answer 31

JG cells

Question 32

What is renin?

Answer 32

A proteolytic enzyme

Question 33

What does renin act on?

Answer 33

Angiotensinogen

Question 34

Where is angiotensinogen constantly produced from?

Answer 34

Liver

Question 35

Where is ACE found?

Answer 35

Vascular endothelium | Pulmonary circuit

Question 36

What does angiotensin II stimulate the release of from the adrenal cortex?

Answer 36

Aldosterone

Question 37

Where in the adrenal cortex is aldosterone produced?

Answer 37

Zona Glomerulosa

Question 38

What is the rate - limiting step in the RAAS pathway?

Answer 38

Production of renin

Question 39

When is renin released?

Answer 39

When pressure in the afferent arteriole decreases, detected by JG cells Sympathetic innervation

Question 40

What are the JG cells described as?

Answer 40

Renal baroreceptors

Question 41

When NaCl levels reduce, what happens to renin production?

Answer 41

Increases

Question 42

What inhibits renin production?

Answer 42

Angiotensin II | ADH

Question 43

In the kidneys, what detects changes in osmolarity?

Answer 43

Macula densa

Question 44

In hypovoleamia, where does Na reabsorption occur?

Answer 44

Proximal & distal tubules

Question 45

What 3 things does Angiotensin II mediate?

Answer 45

Aldosterone secretion Potent vasoconstriction Stimulates ADH secretion

Question 46

What does auto regulation ensure?

Answer 46

GFR maintained

Question 47

What has the biggest effect on ECF composition, volume or osmolarity in hypovolaemic conditions?

Answer 47

Volume

Question 48

With a small reduction in ECF volume, what is there a large increase in?

Answer 48

ADH secretion

Question 49

What has the biggest effect on ADH secretion, volume or osmolarity in normovolaemic conditions?

Answer 49

Osmolarity

Question 50

What does ANP promote?

Answer 50

Na excretion

Question 51

What happens to K levels in the presence of Aldosterone?

Answer 51

Loss of K, reabsorption of Na

Question 52

What effect does aldosterone have on fluid volume?

Answer 52

Increased volume

Question 53

What is the urination of Na called?

Answer 53

Natruiresis

Question 54

What overrides Aldosterone?

Answer 54

ANP

Question 55

What is Conn's syndrome?

Answer 55

Hyperaldosteronism | Tumour of the adrenal cortex

Question 56

Where is ANP secreted from in response to what?

Answer 56

Atrial cells | Increased blood volume

Question 57

What does hyperglycaemia lead to? Why?

Answer 57

osmotic diuresis | Exceeds maximum reabsorptive capacity

Question 58

In DM, does water move out at the descending Loop of Henle? Why?

Answer 58

No | High levels of Na & glucose present therefore osmotically active

Question 59

Because water does not move out at the descending limb, the fluid will be less ____ in the ascending limb in DM.

Answer 59

Concentrated

Question 60

In DM, a large volume of ____ & ____ is delivered to the distal tubule.

Answer 60

NaCl | Water

Question 61

In DM, what happens to the medullary interstitial gradient?

Answer 61

Lost

Question 62

Under normal conditions, a large volume of NaCl & water delivered to the distal tubule will result in...

Answer 62

Diuresis, loss of NaCl & water

Question 63

If a large amount of NaCl is delivered to the distal tubule, what happens to renin secretion?

Answer 63

Inhibits renin secretion

Question 64

In DM, why does ADH have little effect at the CD?

Answer 64

Loss of the medullary interstitial gradient

Question 65

In DM, urinary diuresis occurs resulting in how much urine being produced/ day?

Answer 65

6-8L/day

Question 66

What is one of the first symptoms experienced in DM?

Answer 66

Thirst

Question 67

In DM, if diuresis occurs what will happen to the BP? What will be the worst outcome?

Answer 67

Hypotension | Hyperglycaemic coma

Question 68

Why does hyperglycaemic coma occur?

Answer 68

Inadequate blood flow to the brain

Question 69

Why does hypoglycaemic coma occur?

Answer 69

Inadequate glucose to the brain

Question 70

What can loop diuretics cause?

Answer 70

K loss

Question 71

Why is K lost with the use of loop diuretics?

Answer 71

Inhibits Na-K-Cl cotransporter.