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Endocrine Involvement: 1. ADH

• antidiuretic hormone (vasopressin) is a peptide hormone secreted by the pituitary gland

• regulates the amount of water excreted by the kidneys.

• causes the kidneys to reabsorb water directly from the distal tubules

• concentrates the salts and waste products in the filtrate, which will eventually become urine

• regulated by the hypothalamus

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• dehydration or stress will raise ADH secretion and water will be retained.

• Alcohol inhibits ADH secretion.

• Failure of the pituitary to produce ADH results in diabetes insipidus.

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2. Aldosterone

• a steroid hormone produced by the adrenal gland

• regulates sodium and potassium balance in the blood– increases sodium reabsorption from the distal tubule and

the collecting duct

• responsible for the reabsorption of about 2% of filtered sodium in the kidneys, which is nearly equal to the entire sodium content in human blood under normal conditions

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Aldosterone and blood pressure

• Blood pressure receptors near the glomerulus detect low blood pressure.

• Glomerulus releases renin, an enzyme that converts angiotensinogen, a plasma protein produced by the liver, into angiotensin.

• Angiotensin causes the constriction of blood vessels and raises blood pressure.

• ..and causes release of aldosterone from the adrenal glands to increase sodium reabsorption and increase blood pressure.

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Fig. 49.22(TE Art)Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Low bloodpressure

Bowman'scapsule

Distalconvolutedtubule

Glomerulus

Afferentarteriole

Efferentarteriole

Loopof Henle

Increased NaCland H2O

reabsorption

Increasedblood

volume

Negativefeedback

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Low bloodflow

Proximalconvolutedtubule

Renin

Adrenalcortex

Angiotensinogen

Angiotensin II

3Juxtaglomerularapparatus

Kidney

Aldosterone

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Kidney Dialysis

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Dialysis and kidney transplants

• humans can live normally with just one kidney

• if renal function is impaired, various forms of medications are used, while others are contraindicated

– provided that treatment is begun early, it may be possible to reverse chronic kidney failure due to diabetes or high blood pressure

• if creatinine clearance (a measure of renal function) has fallen very low ("end-stage renal failure"), or if the renal dysfunction leads to severe symptoms, dialysis is commenced.

• Dialysis is a medical procedure, performed in various different forms, where the blood is filtered outside of the body.

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Kidney Dialysis Machine

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Kidney Transplant

• the only cure for end stage renal failure; dialysis, is a supportive treatment; a form of "buying time”

• The first successful kidney transplant was announced on March 4, 1954 at Peter Bent Brigham Hospital in Boston. The surgery was performed by Dr. Joseph E. Murray, who was awarded the Nobel Prize in Medicine in 1990 for this feat.

• There are two types of kidney transplants: – living donor transplant – cadaveric (dead donor) transplant.

• In both cases, the recipient of the new organ needs to take drugs to suppress their immune system to help prevent their body from rejecting the new kidney.

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Kidney Transplant

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Kidney transplant

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Kidney Transplant