Renal - Hormonal Regulation of Body SALTS - Lecture 8 Flashcards Preview

FHB - Pulmonary & Renal - Exam 2 > Renal - Hormonal Regulation of Body SALTS - Lecture 8 > Flashcards

Flashcards in Renal - Hormonal Regulation of Body SALTS - Lecture 8 Deck (29)
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1
Q

What is positive Na balance?

Negative Na balance?

A

Positive - intake > Na excretion

negative: Intake < excretion

2
Q

What are the major solutes of ECF?
What are the major determinants of ECF osmolality?
What is the major determinant of ECF volume?

A
  1. Na
  2. Na, Cl, HCO3-
  3. ECF volume relies on ECF osmolality

increase Na - Increases osmolality - increases H20 reabsorption - decreases osmolality & increases ECF volume

3
Q

What is ECV? What does this vary directly with in normal individuals?

A

Portion of ECV volume within the vascular system that is effectively perfusing the tissues

- in normal individuals ECV varies directly with ECF 
also
1. Volume of vascular system
2. Arterial BP
3. Cardiac Output
4
Q

Describe how changes in ECF can generate changes in ECV via Arterial BP and Cardiac Output.

A

Decrease ECF - decrease vascular volume - decrease BP or Decrease CO sensed as decreased ECV

(opposite for increase in ECF)

5
Q

When are situations in which ECF and ECV vary independently?

A

DISEASE!

  1. CHF
  2. Hepatic Cirrhosis
  3. Pleural Effusion
6
Q

What happens in the following conditions?

  1. Increased Cardiac Atrial Stretch
  2. Pulmonary Vascular Engorgement
A
  1. Increased Cardiac Atrial Stretch –> increased ANP = NATRIURESIS (excretion of Na in urine)
  2. Pulmonary Vascular Engorgement –> decreased sympathetics & decreased ADH!
    = Water Diuresis
7
Q

What are the 4 afferent sensors monitoring the effective circulating volume?

A
  1. Low-Pressure Sensors (venous side of circulation
    - atrial stretch
    - pulmonary engorgement
  2. High Pressure Sensors (arterial side)
    - aortic arch/carotid sinus
    - slow tubular flow
  3. Hepatic Sensors
    - increased liver pressure
    - increased portal vein Na sensors
  4. CNS sensors for Na
    - increased Na in carotid artery & CSF
8
Q

Describe the end result of the following:

  1. High Pressure Sensors (arterial side)
    - aortic arch/carotid sinus
    - slow tubular flow
A
  1. High Pressure Sensors (arterial side)
    - aortic arch/carotid sinus: decrease sympathetics & ADH
    - slow tubular flow: stimulation of JGA which increases renin
9
Q

Describe the end result of the following:

  1. Hepatic Sensors
    - increased liver pressure
    - increased portal vein Na sensors
A
  1. Hepatic Sensors
    - increased liver pressure: decreased sympathetics & Increased Na excretion
    - increased portal vein Na sensors: decreased sympathetics & Increased Na excretion
10
Q

Describe the end result of the following:

  1. CNS sensors for Na
    - increased Na in carotid artery & CSF
A
  1. CNS sensors for Na
    - increased Na in carotid artery & CSF :

decreased sympathetics & increased Na excretion

11
Q

What are the efferent effectors regulating effective circulating volume? (3)

A
  1. Renal Sympathetic Nerves (salt retention or excretion)
  2. RAA system: SALT RETENTION
  3. ANP: Salt excretion
12
Q

What 3 factors are important in stimulating renin secretion?

A
  1. Perfusion Pressure: when reduced, afferent arteriole senses & secretes renin
  2. Sympathetic Nerve Activity: activation of the fibers that innervate afferent arterioles increases renin (b-adrenergic)
  3. Delivery of NaCl to the Macula Densa :
    tubuloglomular feedback
    - decreased delivery of NaCl causes enhanced Renin secretion
13
Q

When there is increased NaCl sensed by the macula densa in Tubuloglomular Feedback, is renin secretion increased or decreased?

What about increased sympathetic activity?

Decreased perfusion?

A
  1. Increased NaCl - Renin secretion REDUCED
  2. Increased sympathetic = increased Renin
  3. Decreased perfusion = increased renin
14
Q

Where is ACE found? What is its function?

A

In the lung

  • functions to convert Angiotensin I to Angiotensin II
15
Q

What is the function of angiotensin ii? (3)

A
  1. Sympathetic Vasoconstriction of afferent arteriole (granular cells)
  2. Stimulate ADH release from posterior pituitary & thirst
  3. Stimulate Aldosterone release from adrenal cortex to add new Na-K ATP as pumps
16
Q

What hormone causes the production of new Na-K ATP as pumps? What is the purpose of these pumps?

A

Aldosterone

  • increase Na reabsorption & K+ secretion & Excretion
  • enhanced NaCl reabsorption by proximal tubule, thick ascending limb, distal tubule, and collecting duct
  • increase Na reabsorption means increased water reabsorption
17
Q

Where is angiotensionogen produced?

A

Liver

18
Q

The main overall affect of the RAA system is what?

A

Decrease Na+ and Water excretion

19
Q

What is the source of ANP? Urodilatin?

A

ANP - cardiac atria

Urodilatin - kidney (endogenously produced)

20
Q

What stimuli promote ANP release? (3)

A
  1. Increased ECFV
  2. Increased Arterial Pressure - BP
  3. Increased Venous Pressure - BP
21
Q

What are the affects of ANP? (4)

A
  1. Decreased ADH –> water diuresis
  2. Increased GFR –> Natriuresis (increased na excretion)
  3. Decreased Aldosterone –> decreased Na reabsorption
  4. Decreased Renin –> decreased AT-II –> decreased Aldosterone (indirect) –> decreased Na reabsorption
22
Q

What is achieved when Na excretion matches Na intake?

A

net zero Na balance

23
Q

When does the kidney reabsorb more than 99% of filtered Na+?

A

During Euvolemia

24
Q

What is the percentage of Na reabsorbed in the following:

  1. PT
  2. TAL
  3. DT
  4. CD
A
  1. Proximal Tubule - 67%
  2. TAL - 25%
  3. DT - 5%
  4. CD - 3%
25
Q

What happens during effective circulating volume expansion? What are the 3 integrated responses to increased ECV?

What happens during Effective Circulating Volume Contraction?

A
  • excess body water is wasted by increasing Na excretion
  1. Increased GFR
  2. Decreased Na reabsorption in PT
  3. Decreased Na reabsorption in CD
  • the opposite is true for Effective Circulating Volume Contraction –> deficit in body water is conserved by increasing Na reabsorption in PT and CD and decreasing GFR
26
Q

What are the two most common causes for generalized edema formation?

A
  1. Increased Pc (capillary hydrostatic pressure)

2. Decreased pi C (capillary oncotic pressure)

27
Q

When fluid is lost to the interstitial, what happens to ECV and plasma volume? What are the clinical results of this (4)?

A
  1. ECV and Plasma volume DECREASE
  2. Pulmonary Edema
  3. Pleural Effusions (expansion of serous fluid spaces)
  4. Abdominal Ascites
  5. Edema of Ankles
28
Q

How can edema fluid be removed? (what can be administered)

A

Diuretics

29
Q

Why is CHF considered a vicious cycle of congestion?

A

Because fluid moves into the interstitial due to increased venous pressure & thus capillary hydrostatic pressure, there is a consequential decrease in Plasma Volume and ECV

  • the decreased ECV is detected by baroreceptors
  • sympathetic activity is stimulated
  • increased NaCl and H20 reabsorption which increases plasma volume and further exacerbates the issue