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Antidiuretic hormone (adh)

Diuretics are drugs that can increase water loss by interfering with the recapture of solutes and water from the forming urine. They are often prescribed to lower blood pressure. Coffee, tea, and alcoholic beverages are familiar diuretics. ADH, a 9-amino acid peptide released by the posterior pituitary, works to do the exact opposite. It promotes the recovery of water, decreases urine volume, and maintains plasma osmolarity and blood pressure. It does so by stimulating the movement of aquaporin proteins into the apical cell membrane of principal cells of the collecting ducts to form water channels, allowing the transcellular movement of water from the lumen of the collecting duct into the interstitial space in the medulla of the kidney by osmosis. From there, it enters the vasa recta capillaries to return to the circulation. Water is attracted by the high osmotic environment of the deep kidney medulla.

Endothelin

Endothelins , 21-amino acid peptides, are extremely powerful vasoconstrictors. They are produced by endothelial cells of the renal blood vessels, mesangial cells, and cells of the DCT. Hormones stimulating endothelin release include angiotensin II, bradykinin, and epinephrine. They do not typically influence blood pressure in healthy people. On the other hand, in people with diabetic kidney disease, endothelin is chronically elevated, resulting in sodium retention. They also diminish GFR by damaging the podocytes and by potently vasoconstricting both the afferent and efferent arterioles.

Natriuretic hormones

Natriuretic hormones are peptides that stimulate the kidneys to excrete sodium—an effect opposite that of aldosterone. Natriuretic hormones act by inhibiting aldosterone release and therefore inhibiting Na + recovery in the collecting ducts. If Na + remains in the forming urine, its osmotic force will cause a concurrent loss of water. Natriuretic hormones also inhibit ADH release, which of course will result in less water recovery. Therefore, natriuretic peptides inhibit both Na + and water recovery. One example from this family of hormones is atrial natriuretic hormone (ANH), a 28-amino acid peptide produced by heart atria in response to over-stretching of the atrial wall. The over-stretching occurs in persons with elevated blood pressure or heart failure. It increases GFR through concurrent vasodilation of the afferent arteriole and vasoconstriction of the efferent arteriole. These events lead to an increased loss of water and sodium in the forming urine. It also decreases sodium reabsorption in the DCT. There is also B-type natriuretic peptide (BNP) of 32 amino acids produced in the ventricles of the heart. It has a 10-fold lower affinity for its receptor, so its effects are less than those of ANH. Its role may be to provide “fine tuning” for the regulation of blood pressure. BNP’s longer biologic half-life makes it a good diagnostic marker of congestive heart failure ( [link] ).

Parathyroid hormone

Parathyroid hormone (PTH) is an 84-amino acid peptide produced by the parathyroid glands in response to decreased circulating Ca ++ levels. Among its targets is the PCT, where it stimulates the hydroxylation of calcidiol to calcitriol (1,25-hydroxycholecalciferol, the active form of vitamin D). It also blocks reabsorption of phosphate (PO 3 ), causing its loss in the urine. The retention of phosphate would result in the formation of calcium phosphate in the plasma, reducing circulating Ca ++ levels. By ridding the blood of phosphate, higher circulating Ca ++ levels are permitted.

Major hormones that influence gfr and rfb

This table shows the stimulus, effect on GFR (glomerular filtration rate), and effect on RBF (renal blood flow) for a variety of vasoconstrictors and vasodilators. The first vasoconstrictor is input from the sympathetic nerves that result in the secretion of epinephrine and norepinephrine. The stimulus is a decrease in extracellular fluid volume (ECFV). The second vasoconstrictor is angiotensin II. The stimulus is a decrease in ECFV. The third vasoconstrictor is endothelin. The stimulus is an increase in stretch, bradykinin, angiotensin II, and epinephrine along with a decrease in ECFV. All three of these vasoconstrictors decrease GFR and also decrease RBF. The first vasodilator is the prostaglandins PGE1, PGE2, and PGI2. The stimulus is a decrease in ECFV, an increase in shear stress, and  an increase in angiotensin II. The second vasodilator is nitric oxide (NO). The stimulus is increasing shear stress, acetylcholine, histamine, bradykinin, ATP, and adenosine. The third vasodilator is bradykinin. The stimulus is the presence of prostaglandins and a decrease in angiotensin-converting enzyme. The fourth vasodilator is natriuretic peptides, including ANP and B-type. The stimulus is an increase in ECFV. All four of the vasodilators increase GFR and also increase RBF, with the exception of the natriuretic peptides, which cause no change in RBF. Prostaglandins also either increase or have no effect on GFR.

Chapter review

Endocrine hormones act from a distance and paracrine hormones act locally. The renal enzyme renin converts angiotensinogen into angiotensin I. The lung enzyme, ACE, converts angiotensin I into active angiotensin II. Angiotensin II is an active vasoconstrictor that increases blood pressure. Angiotensin II also stimulates aldosterone release from the adrenal cortex, causing the collecting duct to retain Na + , which promotes water retention and a longer-term rise in blood pressure. ADH promotes water recovery by the collecting ducts by stimulating the insertion of aquaporin water channels into cell membranes. Endothelins are elevated in cases of diabetic kidney disease, increasing Na + retention and decreasing GFR. Natriuretic hormones, released primarily from the atria of the heart in response to stretching of the atrial walls, stimulate Na + excretion and thereby decrease blood pressure. PTH stimulates the final step in the formation of active vitamin D3 and reduces phosphate reabsorption, resulting in higher circulating Ca ++ levels.

Questions & Answers

what is the best book that shows unit 1 about cell unit 2 about tissue unit 3 about embroyology
Abraham Reply
2
Hellen
to understand structure of body able to understand function of system. to understand how to build human body and function
Dereje Reply
hi
Neela
to determine body structures
Petra Reply
to know the use of each and every part of our body
Petra
to understand how our body structures work to support our lives
Petra
Is this a question?
Tammy
So what was the question?
Thamie
All the body work together to make the whole organism life possible
Kwasi
what is carbon dioxide respiratory system why?
Prachi Reply
Carbon dioxide (CO2) is involved with the chemical process of cellular respiration. It is produced as a cellular waste product during the decomposition reactions and serves an important role in maintaining the appropriate acid-base balance in the body.
Tammy
thank you
Prachi
You're welcome!
Tammy
i have not under stood human heart
Simbwa Reply
means?
Dilshan
why a man became wild at the time of sexual intercourse. reason?
Soul
what is anatomy
philemon Reply
what is anatomy in terms of medicine
philemon
it is the study of human and animal form by observing and examined them and sometimes dissecting them and view the tiny thing by the use of microscope
Kwasi
anatomy is simply the scientific study of the body's structures
Petra
study of human body and animal
Crystal
why a man becomes wild at the time of sexual intercourse
Soul
Anatomy is the study of structure of the human body.
Tammy
Physiology is the study of the functions of the human body
Tammy
Describe early studies into the working of human body.
Tonny Reply
please guys help me to answer this question; Define the two divisions of the skeleton ?
Jonathan Reply
two example of appendicular skeleton
Jonathan
upper limb ;eg humerus n lower limb;eg tibia
BRIAN
write notes on the level of organizations of the body .citing examples for each level
Kaddijatou Reply
Jonathan Nyakpaab
Jonathan
what is pathology
Ericka Reply
1 What is Nasogastric Tube 2 what is the difference between Nasogastric Aspiration and Nasogastric Feeling
ONOJA Reply
You measure a patient’s blood pressure at 130/85. Calculate the patient’s pulse pressure and mean arterial pressure. Determine whether each pressure is low, normal, or high.
ONOJA
normal blood pressure 120/80
Mohd
what are nocciceptors
Soul
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Mohd
1 Its a flexible tube of plastic that pass through the nose, down to the eausophagus, and into the stomach, used to add or remove substances in the stomach.
Andile
2 Nasogastric aspiration is process of draining stomach contents via a tube and Nasogastric feeding is a process of giving food liquid through nasogastric tube
Andile
andile sir what is meant by clonoscopy
Soul
colonoscpopy is an exam use to detect abnormalities in the small intestine or the colon
Kwasi
What is the skin
Astony Reply
What is physiology?
Njaleny Reply
it is the study of the structure of the human body and its reationship
Hannah
Physiology is the function of a living organism.
Tammy
It is the study of human body and how it works.
Excellent
if physiology is the function of a living organism.What method is keep for living organism.
Ayoore
what are Nocciceptors
Soul
Nocciceptors are pain receptor
Kwasi
Or is a sensory neutron that responds to damage
Kwasi
It is d entrance to the uterus
Umunna Reply
It is a small sensitive part of female sex organ which is found above d entrance to the vagina
Umunna
A small hole in d skin which contains d root of a hair
Umunna
A thin membrane which covers d entrance to the vagina in young girls
Umunna
Is a gland that produces milk in women and other female mammals
Umunna
A repeated process in which a woman's uterus gets ready for pregnancy which ends in a period if she does not get pregnant
Umunna
hello
Tamba
hi sir
Mir
Hi
Umunna
why should one consider studying neuroanatomy to physiology?
Ramadhan
hy
kaabe
hi
HANIFA
hmm
Hussain
hi
Muhammad
Hi
miya
hello
Adnan
hello
Ayoore
neuroanatomy is the study of the brain, spinal cord, and nerves whiles physiology is the study of the structures of a human body and it's functions neuroanatomy I think is a specified area ie u study everything about the brain , spinal cord and nerves. But with the physiology , it's a broad one
Petra
neuroanatomy I think is a specified area ie u study everything about the brain , spinal cord and nerves.
Petra
neuroanatomy is the study of the brain, spinal cord, and nerves whiles physiology is the study of the structures of a human body and it's functions neuroanatomy I think is a specified area ie u study everything about the brain , spinal cord and nerves. But with the physiology , it's a broad one
Petra
But with the physiology u study everything about the structures of human body
Petra
so in summary describe the level of structural complexity within the body
Freda Reply
how can we describe briefly the levels of organization
Frimpong

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Source:  OpenStax, Anatomy & Physiology. OpenStax CNX. Feb 04, 2016 Download for free at http://legacy.cnx.org/content/col11496/1.8
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