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By the end of this section, you will be able to:
  • Describe how each of the following functions in the extrinsic control of GFR: renin–angiotensin mechanism, natriuretic peptides, and sympathetic adrenergic activity
  • Describe how each of the following works to regulate reabsorption and secretion, so as to affect urine volume and composition: renin–angiotensin system, aldosterone, antidiuretic hormone, and natriuretic peptides
  • Name and define the roles of other hormones that regulate kidney control

Several hormones have specific, important roles in regulating kidney function. They act to stimulate or inhibit blood flow. Some of these are endocrine, acting from a distance, whereas others are paracrine, acting locally.

Renin–angiotensin–aldosterone

Renin is an enzyme that is produced by the granular cells of the afferent arteriole at the JGA. It enzymatically converts angiotensinogen (made by the liver, freely circulating) into angiotensin I. Its release is stimulated by prostaglandins and NO from the JGA in response to decreased extracellular fluid volume.

ACE is not a hormone but it is functionally important in regulating systemic blood pressure and kidney function. It is produced in the lungs but binds to the surfaces of endothelial cells in the afferent arterioles and glomerulus. It enzymatically converts inactive angiotensin I into active angiotensin II. ACE is important in raising blood pressure. People with high blood pressure are sometimes prescribed ACE inhibitors to lower their blood pressure.

Angiotensin II is a potent vasoconstrictor that plays an immediate role in the regulation of blood pressure. It acts systemically to cause vasoconstriction as well as constriction of both the afferent and efferent arterioles of the glomerulus. In instances of blood loss or dehydration, it reduces both GFR and renal blood flow, thereby limiting fluid loss and preserving blood volume. Its release is usually stimulated by decreases in blood pressure, and so the preservation of adequate blood pressure is its primary role.

Aldosterone, often called the “salt-retaining hormone,” is released from the adrenal cortex in response to angiotensin II or directly in response to increased plasma K + . It promotes Na + reabsorption by the nephron, promoting the retention of water. It is also important in regulating K + , promoting its excretion. (This dual effect on two minerals and its origin in the adrenal cortex explains its designation as a mineralocorticoid.) As a result, renin has an immediate effect on blood pressure due to angiotensin II–stimulated vasoconstriction and a prolonged effect through Na + recovery due to aldosterone. At the same time that aldosterone causes increased recovery of Na + , it also causes greater loss of K + . Progesterone is a steroid that is structurally similar to aldosterone. It binds to the aldosterone receptor and weakly stimulates Na + reabsorption and increased water recovery. This process is unimportant in men due to low levels of circulating progesterone. It may cause increased retention of water during some periods of the menstrual cycle in women when progesterone levels increase.

Questions & Answers

Which of the following accurately describe external resipration
Gwendolyn Reply
from the heart to the lungs
Phee
I think it's not outside organ of respiratory all respiratory organ are inside of human body
Moha
diffusion of CO2 and oxygen at a pulmonary capillary surrounding an alveolar sac.
Jeremiah
In other words, from the external environment to the lungs (alveoli) then to the pulmonary capillary then to the heart. So this is a stage of inhalation. inhale = external respiration.
Jeremiah
What kind of discussion
horyaal Reply
what is the function of the placenta
Nchimunya Reply
The placenta acts to provide oxygen and nutrientsto the fetus, whilst removing carbon dioxide and other waste products.
Moha
Also it's the barrier through which the mother is connected to the fetus.
Samuel
I want to discuss... atherosclerosis.., everything about it, about to treatment n prevention at age 50 +
Doctors
Please participate in discussion
Doctors
ok let's discuss now
Moha
first define the word artherosclerosis
Moha
a disease of the arteries characterized by the deposition of fatty material on their inner walls.
tabe
hardening of the arteries, due to fats..
jenelyn
Q = which type of fat utilized for this.., I.e LDL, HDL, TG, VLDL...?
Doctors
Atherosclerosis is a condition of deposition of plaque inside the artries
Arvind
Plaque include such as fat, chalestrol, calcium etc
Arvind
Thank you kumar...., is there any way that we can protect these plaques without any medicines., I. e exercises n food stuffs
Doctors
go to the gym
Moha
what is chylomicrons?
Moha
how can plaque buildup in The angina or vessels ?
Moha
Atherosclerosis is a condition of deposition of plaque inside the artries
Doctors
atherosclerosis can also be caused by tortuousness of arteries with old age as contributing factor.
edward
You tube Prof Fink...he is an amazing lecturer and does a brilliant job on arteriosclerosis
Jacqueline
what are cell
Chigozie Reply
The basic structural and functional unit of any living thing. Each cell is a small container of chemicals and water wrapped in a membrane. 
Yusuf
cell is the structural and functional basic unit of life
Zaid
So every living thing was Created From a Cell
Anthony
from a fusion of two cells , the sperm and the egg
Shikoh
What is the only bone that doesn't have any articulation?
Jimmy
that magical fusion of cells
OBED
why body immune system attack and destroy the body own cell during type 1 diabetes?
Sanamacha Reply
It's an autoimmune disease... targeting the pancreas
Claudia
what are the three genetic defects of pregnancy?
Belinda Reply
structure of fallopian tubes
Akash Reply
what z the role played by the transport system
zinitha Reply
how fats are digested in the human body
Nabukwasi Reply
Fat digestion begins in the stomach but some argue in that it starts in the mouth. Reason is because the sublingual gland secretes an enzyme called lingual lipase. However, this enzyme is not activated until it comes into contact with gastric fluids (HCl). In the stomach, HCl breaks down the lipid..
Jeremiah
due to body heat
Mule
into smaller molecules. Going from a triglyceride and a fatty acid to a monoglyceride and a a fatty acid no longer bound to one another. This is known as lipolysis.
Jeremiah
After lipolysis in the stomach from gastric and lingual lipase, an acidic chyme is produced after stomach churning the bolus. The chyme exits the stomach at the pyloric sphincter and enters the first section of the small intestine known as the duodenum.
Jeremiah
in the duodenum. An alkaline mucus from goblet cells neutralizes the acidic chyme to prevent acid burns. After that, the pancreas and gallbladder secrete a number of enzymes to continue lipolysis. Bile from the gallbladder enters the duodenum via common bile duct. The acinar cells in the pancreas...
Jeremiah
secretes pancreatic lipase after enteroendocrine cells in the duodenum secrete a stimulator hormone called CCK. Cck stimulates bile synthesis and secretion as well as pancreatic lipase.
Jeremiah
Bile emuslifies the lipid, allowing the lipases to continue lipolysis
Jeremiah
this breakdown continues until it reaches the jejunum of the small intestines. At this point, the lipid has been broken down small enough to absorbed into the blood stream. So villi in the jejunum, absorb the contents.
Jeremiah
ileum, the last small intestine region, absorbs anything that wasn't absorbed previously. Like minerals, vitamins, bile salts, water soluble material. Villi here complete that task. Fatty acid and glycerol however, are absorbed by lacteals. small lymph vessels. And are transported to the liver.
Jeremiah
That concludes lipid digestion. Anything else that remains is deficated after it travels through the large intestines.
Jeremiah
parents with blood group AB & 0,,,what will b the blood group of their offspring
imran
what are the different branches of anatomy
Nabukwasi
hopefully that helped.
Jeremiah
which ion is low of blood level?
Ezra Reply
what is coagulation?
feng Reply
liquid turning to solid... blood clots.
Kristy
coagulation : liquid blood into blood clots caused with a coagulant.
jaime
when the blood turn from liquid form to solid
June
it said to coagulate by the action of active plasma protein called *fibrin*
Hassan
I.e liquid inform of blood when to solid
Hassan
it is the process by which blood becomes more viscous or becomes thick
CHRISTOPHER
cloting of blood cells
Kabange
clot of blood
Moses
the process of forming semi solid lumps in a liquid
rida
conversion of blood to solid state
Ezra
semi solid., rather than solid form
Doctors
what is pivot functioned
Ever
to less thefriction
Hirsi
how to calculate the micrograph
Ampong Reply
it can be used to knw the disease condition
Akbar Reply
which gland secret tears
Opoku
lacrimal glands
Diego
explain the blood supply to the brain
Brenda Reply
There are two paired arteries which are responsible for the blood supply to the brain; the vertebral arteries, and the internal carotid arteries. These arteries arise in the neck, and ascend to the cranium.
Sabrina
two arteries main vertebral arteries & internal carotid artery
Akbar
Is tissue the same as cells?
Seyram Reply
yes tissues are made up of cells
KJ
nope
Francis
a tissue is made by cells which release the components and rule the built of a specific extracellular matrix
Manuel
OK thanks very much
Seyram
ya
Ananthapadmanabha
what is the control system
zinitha
which system
Brenda
Nervous system is just one control system in the body. Endocrine system is the other.
Sabrina

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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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