Endocrine Functions of the Kidney Flashcards

1
Q

What are the primary endocrine functions of the kidney?

A

Production of erythropoietin, renin, activation of vitamin D, and production of prostaglandins.

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2
Q

What hormone is primarily produced by the kidneys in response to hypoxia?

A

Erythropoietin (EPO).

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3
Q

How does erythropoietin (EPO) function in the body?

A

EPO stimulates the production of red blood cells in the bone marrow.

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4
Q

Which cells in the kidney produce erythropoietin?

A

Peritubular fibroblasts in the renal cortex.

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5
Q

How does erythropoietin regulate red blood cell production?

A

By binding to erythroid progenitor cells in the bone marrow and promoting their maturation into red blood cells.

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6
Q

What triggers the release of erythropoietin from the kidneys?

A

Low oxygen levels (hypoxia) in the blood.

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7
Q

What is the role of the kidneys in the renin-angiotensin-aldosterone system (RAAS)?

A

The kidneys release renin, which activates the RAAS to regulate blood pressure and fluid balance.

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8
Q

How do the juxtaglomerular cells contribute to the endocrine function of the kidneys?

A

Juxtaglomerular cells produce renin in response to decreased blood pressure or blood flow to the kidneys.

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9
Q

What stimulates the secretion of renin from the kidneys?

A

Decreased renal perfusion, sympathetic nervous system activation, and low sodium chloride concentration in the distal tubule.

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10
Q

Describe the process by which renin leads to the production of angiotensin II.

A

Renin converts angiotensinogen to angiotensin I, which is then converted to angiotensin II by angiotensin-converting enzyme (ACE) in the lungs.

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11
Q

How does angiotensin II affect blood pressure?

A

Angiotensin II constricts blood vessels, increasing blood pressure and stimulating aldosterone release.

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12
Q

What is the role of aldosterone in kidney function?

A

Aldosterone increases sodium reabsorption and potassium excretion in the kidneys, promoting water retention.

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13
Q

How does the activation of RAAS contribute to sodium and water retention?

A

By increasing aldosterone secretion, which enhances sodium and water reabsorption in the distal tubules and collecting ducts.

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14
Q

What enzyme do the kidneys produce that is involved in vitamin D metabolism?

A

1-alpha-hydroxylase.

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15
Q

Describe the role of 1-alpha-hydroxylase in the kidneys.

A

It converts 25-hydroxyvitamin D to 1,25-dihydroxyvitamin D (calcitriol), the active form of vitamin D.

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16
Q

How do the kidneys convert vitamin D into its active form?

A

By hydroxylating 25-hydroxyvitamin D in the proximal tubules.

17
Q

What is the active form of vitamin D produced by the kidneys?

A

1,25-dihydroxyvitamin D (calcitriol).

18
Q

How does active vitamin D (calcitriol) affect calcium homeostasis?

A

Calcitriol increases calcium absorption from the gut, reabsorption in the kidneys, and release from bones.

19
Q

What is the role of the kidneys in phosphate metabolism?

A

By regulating the reabsorption and excretion of phosphate in response to various hormones.

20
Q

How does parathyroid hormone (PTH) influence kidney function in relation to calcium and phosphate?

A

PTH increases calcium reabsorption and decreases phosphate reabsorption in the kidneys.

21
Q

What is the relationship between kidney function and the regulation of blood pressure?

A

By regulating the RAAS and producing vasodilatory prostaglandins.

22
Q

How does the kidney’s endocrine function impact systemic vascular resistance?

A

Angiotensin II and aldosterone, products of the RAAS, increase systemic vascular resistance and blood volume.

23
Q

What is the function of prostaglandins produced by the kidneys?

A

Prostaglandins act as vasodilators, increasing renal blood flow and counteracting vasoconstriction.

24
Q

How do renal prostaglandins affect renal blood flow?

A

They help maintain adequate blood flow to the kidneys, particularly during stress or injury.

25
What role do the kidneys play in the regulation of acid-base balance through endocrine mechanisms?
By secreting hydrogen ions and reabsorbing bicarbonate, influencing systemic acid-base balance.
26
How does the kidney produce and utilize ammonia in acid-base balance?
Ammonia is produced and secreted by the kidneys to buffer hydrogen ions in the urine.
27
What is the significance of the kidney's production of kallikrein?
Kallikrein is involved in the production of kinins, which are vasodilators.
28
How does kallikrein contribute to blood pressure regulation?
Kinins produced from kallikrein activity lower blood pressure by dilating blood vessels.
29
What are the effects of atrial natriuretic peptide (ANP) on kidney function?
ANP increases glomerular filtration rate and sodium excretion, lowering blood pressure.
30
How does the endocrine function of the kidney influence fluid and electrolyte balance in the body?
By regulating the balance of sodium, potassium, calcium, phosphate, and water through various hormonal mechanisms.