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MD1 URO - EXAM 1 > Le néphron distal (les tubules distal et collecteur) / Le contrôle du volume circulant efficace > Flashcards

Le néphron distal (les tubules distal et collecteur) / Le contrôle du volume circulant efficace Flashcards

(42 cards)

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1
Q

What are the different parts of the néphron distal?

A
  1. Tubule distale
    1. ** Segment connecteur (transition segment distalo-collecteur)
  2. Tubule collecteur
    1. Cortical
      • Cellules principales
      • Cellules intercalaires
    2. Médullaire
      • Médullaire externe
      • Médullaire interne
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2
Q

What are the functions of the distal nephron? (4)

A

Water reabsorption

Sodium reabsorption

Secretion of potassium

Secretion of hydrogen ions (acid)

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3
Q

What % of NaCl is reabsorbed in each segment of the nephron?

A
  1. Proximal tubule: 70%
  2. Anse of Henle: 20%
  3. Distal tubule: 5%
  4. Collector tubule: 4%
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4
Q

Where does the distal nephron start?

A

Macula densa

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5
Q

What are the different segments of the néphron distal and the hormones/membrane transport used?

A

Tubule distal:

  • Membrane transport:
    • Co-transport: Na+-Cl- —> only found in distal

Tubule collecteur cortical:

  • Membrane transport:
    • Cellule principale
      • Na+ canal
      • K+ canal
      • Transport de l’eau
    • Cellules intercalaire
      • Secretion of H+
  • Hormones:
    • Aldosterone
      • Na+ and K+ channels, H+ secretion
    • ADH
      • Water transport

Tubule collecteur médullaire: médullaire interne

  • Membrane transport:
    • Canal à Na+
    • Transport de l’eau
    • Transport de l’urée
  • Hormones:
    • PNA
      • Canal à Na+
    • ADH
      • Transport de l’eau
      • Transport de l’urée
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6
Q

What do the cellules tubulaire distale look like?

A
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7
Q

What is the segment connecteur?

A

A couple of cells; with characteristics of the distal tubule and collector tubule

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8
Q

What are the functions of the two different cell types in the tubule collecteur cortical?

A

Cellules principales

65% —> reabsorb NaCl, H2O and secrete K+

Cellules intercalaires

35% —> secrete H+

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9
Q

What do the cellules principales look like?

A
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10
Q

What is the motor of of the cellule principale?

A

Basolateral Na+ K+ ATPase

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11
Q

What is the main function of the cellules intercalaires?

A

Equilibre acido-basique

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12
Q

What do the cellules intercalaires look like?

A
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13
Q

What kind of cells are found in the médullaire interne (papille)?

A

cellules du tubule collecteur papillaire

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14
Q

What does PNA do?

A

Block reabsorption of Na+ —> natriurèse

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15
Q

What are the locations/hormones used for the different functions of the distal nephron?

A

H2O reabsorption: tubule collecteur (ADH (vasopressin))

Na+ reabsorption: tubules distal + collecteur (Aldosterone, PNA)

K+ secretion: principal tubule collecteur (Aldosterone)

H+ secretion: tubule collecteur intercalaire (Aldosterone)

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16
Q

What hormone controls Na+ transport in distal tubule?

A

NONE… NOT UNDER HORMONAL CONTROL!!

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17
Q

What hormone controls Na+ transport in the cellules principales du tubule collecteur?

18
Q

What hormone controls K+ secretion in the cellules principales du tubule collecteur?

19
Q

What hormone controls H+ transport in the cellules intercalaires du tubule collecteur?

20
Q

What hormone controls H2O transport in the cellules principales du tubule collecteur?

21
Q

What hormone controls Na+ transport in the cellules du tubule collecteur papillaire?

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A

PNA (peptide natriurétique de l’oreillette)

22
Q

What is the VCE?

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A

Volume intravasculaire qui perfuse efficacement les tissus

  • Varies with extracellular volume
  • Étroitement liée avec la régulation du balance du Na+
23
Q

Is the VCE measurable?

Study These Flashcards
A

NO! its the “taux de perfusion de la circulation capillaire”

24
Q

What happens when the VCE drops?

Study These Flashcards
A

Drop in urinary Na+ levels….

  • en absence de diurétique ou maladie rénale

If sodium reabsorption is increased… so will water reabsorption which will keep water in

25
How does Na+ balance happen in humans?
26
What is the signal that helps Na+ excretion fluctuate according to Na+ taken in by diet?
Change in volume... tubules see salt ingestion through volume receptors
27
What are the three locations of volume receptors in the body?
1. Circulation cardio-pulmonaire (oreillette gauche) 2. Sinus carotidien et crosse aortique 3. Artérioles afférents
28
What are the principal control mechanisms (effecteurs) of volume regulation? (2)
**Hémodynamie systèmique** **Excrétion rénale de Na+**
29
What is hémodynamie systèmique and how is it controlled?
**Volume control... contenant** * Système nerveux sympathique * Angiotensine II
30
How is sodium excretion dealt with by the kidneys?
**Contenu:** 1. DFG 2. Angiotensine II 3. Hémodynamie du capillaire pétitubulaire 4. Aldostérone 5. SNS 6. PNA
31
What are the effects of angiotensine II? (3)
1. Vasoconstriction 2. Renal Na+ retention 3. Stimulation of aldosterone
32
IMPORTANT OVERVIEW OF VCE CONTROL... MEMORIZE THIS!
33
What is the emergency mechanism for VCE control?
**Secretion of ADH (sécrétion hémodynamique non-osmotique)** * **Tubule collecteur:** * Réabsorption maximale d'eau PEU IMPORTE L'OSMOLALITÉ * **Vaisseaux sanguins:** * Effet vasoconstricteur —\> helps maintain BP
34
How does the improved "schéma d'hydratation" work?
35
Osmorégulation vs régulation volémique:
36
What happens when you infuse the body with isotonic saline? (3)
1. increase VCE without increasing osmolality 2. increase Na+ in urine/water —\> urine iso-osmotique 3. Restore "volume corporel iso-osmotique"
37
What happens when you exercise? (Na loss and water loss)
**Perte de Na+ —\> modérée (CANAL 2)** * Drop in extra-cellular volume —\> drop in VCE * Decrease in Na+ urinaire * _Restore volume corporel iso-osmotique_ **Perte d'eau —\> importante (CANAL 1)** * Increase in plasmatic osmolality * Increase ADH/thirst * Retain water (urine hyper-somolaire) * _Restore volume corporel iso-osmotique_
38
What is monitored and adjusted in each canal? (1, 2 and 4)
39
What is the normal adjustment site of tubular Na+ reabsorption?
Tubule collecteur
40
What will a decrease in NaCl ingestion to to aldosterone secretion?
Increase... to keep NaCl inside body
41
Where is the emergency adjustment site of tubular Na+ reabsorption?
Tubule proximale (ADH)
42
How do AII and noradrenaline stimulate tubular Na+ reabsorption?
Directement et indirectement en resserrant l'artériole efférente...

MD1 URO - EXAM 1 (8 decks)

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