Lecture #38 - Body water - distribution and regulation

Question 1

In the leaky epithelium, the consequence of Na+ abs is that the lumen because ____ ___ and the interstitial becomes ____ ____; this drives what kind of absorption of what ion?

Can Na+ pass through paracellularly?

In the leaky epithelium, the consequence of Na+ abs is a huge ____ ____ over the epithelium; this drives what kind of transport of water?

Answer 1

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Question 2

Body water

1. What percentage of body weight is TBW?
2. What proportion of TBW is ICF?
3. What proportion of TBW is ECF?
4. What proportion of ECF is plasma?
5. What proportion of ECF is interstitial fluid?

Answer 2

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Question 3

What is the osmolarity of the ECF and ICF?

Answer 3

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Question 4

• Total body water remains relatively ____
• Intake and loss of water must _____
• what is adjusted to maintain balance?

Answer 4

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Question 5

Describe using the words hypotonic, hypertonic and isotonic the different segments of loop of henle.

What is the status of urine at the end of the collecting duct dependent on? And what terms are coined for the hypertonic urine and hypotonic urine

Answer 5

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Question 6

1. Changing water content changes what?
2. Fluid shifts between what to equalise?
3. ____ of compartments change
4. Changing water content changes cell _____
5. What is altered and what is impaired?

Answer 6

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Question 7

RBCs are dependent on what type of environment?

Answer 7

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Question 8

1. ICF/ECF have same osmolarity - what number?
2. Water moves freely between ICF and ECF - true or false?
3. Water moves to areas of ___ osmolarity until when?
4. Problem is…..
5. So you regulate ____ to regulate ____ to regulate ______ ____

Answer 8

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Question 9

Explain what happens when you drink too much or too little water.

• ECF
• difference
• water moves
• cells size

Answer 9

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Question 10

TBW alters plasma (ECF) ____

• detected by what in where?
• stimulates what?
• what does this hormone alter?
• so what happens to water?
• i.e. what are the two end outcomes?-

Answer 10

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Question 11

ADH: hormone from where?

1. ADH synthesis
   - in cell body of central neurons (where?)
   - axonal transport to where?
2. ADH release
   -in ___ ____
   -into what?
   (what’s the term for this?)

Answer 11

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Question 12

What are the two main stimuli for release of ADH? What’s the threshold for one?

What is the action of ADH?

By what mechanism does it work? (like where is the receptor etc)

Is the CD epithelium tight or leaky?
Water reabs in what cells of the CD is regulated by ADH?

So apical membrane of CD is either real permeable or not depending on ADH but what about permeability of the basolateral membrane of CD for water?

Answer 12

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Question 13

Without ADH:

• CD relatively ____ to water because?
• what happens to water reabs’
• what happens to volume and osmolarity of urine?

With ADH

• CD more/less permeable to water?
• Water reabs from CD (“down” ___)
• what happens to volume and osmolarity of urine?

Answer 13

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