8. Control of blood volume

Question 1

How is blood volume regulated long term?

Answer 1

Control of body flui volume by the kidneys; renal-body fluid feedback system

Question 2

What happens to urine production when ArtP increases?

Answer 2

Increase

Question 3

What happens to urine production when ArtP decreases?

Answer 3

Decreases

Question 4

What are the primary determinants used to control blood volume?

Answer 4

• Renal output curve for salt and water
• Level of salt and water intake

Question 5

Draw a flow chart of the process to control blood volume

Answer 5

Question 6

When is ADH/vasopressin released?

Answer 6

• Increased osmotic pressure
• hypovolemia
• hypotensin
• angiotensin II

Question 7

Where is ADH released from?

Answer 7

Pituitary gland

Question 8

What detects an increase in osmotic pressure?

Answer 8

Hypothalamic osmopreceptors

Swell/contract depending on the concentration of solutes in the blood

Question 9

What do atrial baroreceptors normally inhibit?

Answer 9

ADH release

Question 10

What does hypovolemia cause?

Answer 10

Decreased baroreceptor firing so increased ADH release

Question 11

What does hypotension cause?

Answer 11

• Decreased baroreceptor firing
• Increased SNS
• Increased ADH

Question 12

What does an increase in angiotensin II cause?

Answer 12

Release of ADH

Question 13

How does ADH increase blood volume?

Answer 13

Increased permeability in renal collecting ducts; stopping the loss of fluid

Question 14

How does ADH affect urine production?

Answer 14

Decreased urine production

Question 15

What happens in severe hypovolemic shock?

Answer 15

ADH release = high and causes vasocontriction, which increases TPR

Question 16

What causes the release of renin?

Answer 16

• Sympathetic nerve activation
• Renal artery hypotension
• Decreased Na⁺ in kidney distal tubules

Question 17

Where is renin released from?

Answer 17

Kidney juxoglomerular cells

Question 18

Where does angiotensin II act?

Answer 18

Acts on resistance vessels increasing TPR

Question 19

What does angiotensin II cause the release of?

Answer 19

Aldosterone from adrenal gland

Question 20

How does aldosterone act?

Answer 20

Increased Na⁺ and water reabsorption

Question 21

What is ANP? and how does it work?

Answer 21

Atrial-natriuetic hormone, whcih is synthesied and stored in the muscle cells in the atria.

Released in response to the stretching of the atria and helps oppose the effects of the RAAS system (counteracts volume overload)

Question 22

What can cause hypovolemia?

Answer 22

• Decrease in whole body volume (haemorrhage)
• Decrease in plasma (burns)
• Decrease in sodium (vomitting)

Question 23

What occurs in hypovolemia intially?

Answer 23

• Decreased SV
• Increased HR
• Decreased CO
• Increased TPR
• Decreased MABP

**Uses CVS mechanisms to compensate

Question 24

What body mechanisms bridge the gap between the neuronal and RAAS systems in hypovolemia?

Answer 24

• Arteriolar contriction
  
  • Decrease hydrostatic pressure
  • Fluid reabsoption
  • temporary redistribution
• Decreased renal blood
• Baroreceptors and thirst

Question 25

What is a result of severe hypovolemia?

Answer 25

Heart Failure