Juxtaglomerular cells (JG cells), also known as granular cells are cells in the kidney that synthesize, store, and secrete the enzyme renin. They are specialized smooth muscle cells mainly in the walls of the afferent arterioles (and some in the efferent arterioles) that deliver blood to the glomerulus. What does the juxtaglomerular cells secrete?
The juxtaglomerular cells secrete renin, and as specialised smooth muscle cells surrounding the afferent arteriole also have the capacity to affect the perfusion of the glomerulus.
What hormone is produced by the juxtaglomerular cells?
Renin Renin is a hormone secreted by the juxtaglomerular cells of the kidney; it interacts with a plasma protein substrate to produce a decapeptide prohormone angiotensin I. What is the juxtaglomerular?
The juxtaglomerular apparatus is a specialized structure formed by the distal convoluted tubule and the glomerular afferent arteriole. It is located near the vascular pole of the glomerulus and its main function is to regulate blood pressure and the filtration rate of the glomerulus.
What are foot processes?
The foot processes known as pedicels that extend from the podocytes wrap themselves around the capillaries of the glomerulus to form the filtration slits. The pedicels increase the surface area of the cells enabling efficient ultrafiltration. Podocytes secrete and maintain the basement membrane. What is produced by granular cells of the juxtaglomerular apparatus?
Renin is produced by juxtaglomerular cells, also known as granular cells. These cells are similar to epithelium and are located in the tunica media of the afferent arterioles as they enter the glomeruli. The juxtaglomerular cells secrete renin in response to: Stimulation of the beta-1 adrenergic receptor.
Frequently Asked Questions(FAQ)
What does the juxtaglomerular apparatus consist of?
The juxtaglomerular apparatus, located in the glomerular hilum, consists of a vascular component (afferent and efferent arterioles and extraglomerular mesangium) and a tubular component (macula densa).
Do granular cells release renin?
Granular cells at the end of the afferent arteriole synthesize and release renin by a process regulated by local changes in arteriolar hydrostatic pressure and stretch, and β-adrenoceptor stimulation by norepinephrine released from perivascular sympathetic nerve terminals [86, 97–99].
What comprises the JG apparatus?
The juxtaglomerular apparatus consists of the juxtaglomerular cells of the afferent glomerular arteriole, the efferent glomerular arteriole, the extraglomerular mesangial cells, and that small portion of the distal tubule known as the macula densa that is located beside the renal glomerulus.
How does renin affect GFR?
The macula densa responds by decreasing ATP release, and there is a subsequent decrease in calcium from the smooth muscle cells of the afferent arteriole. The ensuing result is vasodilation, and increased renin release in an attempt to increase GFR.
What does the Juxtaglomerular complex do?
Do juxtaglomerular cells have baroreceptors?
The juxtaglomerular cells of the af- ferent arteriole act as high-pressure baroreceptors and are able to detect changes in blood pressure. … Activation of the intrarenal baroreceptor mechanism results in the secretion of renin and increased formation of ANG II.
What capillary bed produces filtrate?
Which capillary bed produces filtrate? A (glomerulus. The glomerulosa (capillary bed) in the glomerular capsule produces filtrate due to the high fluid pressure within the vessels.)
Where angiotensinogen is produced?
the liver Angiotensinogen is produced in the liver and is found continuously circulating in the plasma. Renin then acts to cleave angiotensinogen into angiotensin I.
What is the macula densa?
Abstract. Macula densa cells in the distal nephron, according to the classic paradigm, are salt sensors that generate paracrine chemical signals in the juxtaglomerular apparatus to control vital kidney functions, including renal blood flow, glomerular filtration, and renin release.
How do you pronounce Juxtaglomerular apparatus?
What is GFR test?
A test of glomerular filtration rate (GFR) evaluates kidney function. The kidney consists of tiny filters which are called glomeruli that remove waste material from the blood. The GFR test is an assessment of how well this filtration process is working.
What does podocytes mean?
Podocytes are highly specialized cells of the kidney glomerulus that wrap around capillaries and that neighbor cells of the Bowman’s capsule. … The genetic or acquired impairment of podocytes may lead to foot process effacement (podocyte fusion or retraction), a morphological hallmark of proteinuric renal diseases.
Why are podocytes important?
Podocytes play an important role in glomerular function. Together with endothelial cells of the glomerular capillary loop and the glomerular basement membrane they form a filtration barrier. Podocytes cooperate with mesangial cells to support the structure and function of the glomerulus.
Where is capsular space?
The slitlike space between the visceral and parietal layers of the capsule of the renal corpuscle; it opens into the proximal tubule of the nephron at the neck of the tubule. Synonym: bowmans space, filtration space.
What are the two primary cellular components of the Juxtaglomerular apparatus and how is each stimulated?
The JG apparatus is made up of two primary components. The two primary components are the macula densa cells and the granular cells.
What is the difference between a cortical and a juxtaglomerular nephron?
Cortical nephrons have a short loop of Henle, which penetrates only the outer renal medulla. Juxtamedullary nephrons have a long loop of Henle extending deep into the renal medulla. … The juxtamedullary nephrons concentrate or dilute urine.
How does Juxtaglomerular apparatus regulate the kidney function?
The juxtaglomerular apparatus (JGA), consisting of the glomerular afferent and efferent arterioles and the specialized tubular epithelial cells called the macula densa, plays a central role in the regulation of glomerular hemodynamics and renin release.
Which is the correct order of filtrate flow?
extra info: The correct order for filtrate flow through a nephron is Glomerular capsule, PCT, loop of Henle, DCT, collecting duct. Filtrate is formed as plasma filters into the glomerular capsule.
What do Juxtaglomerular cells monitor?
These cells do two things: They monitor blood pressure, by measuring how much the arteriole wall is stretched. They monitor the concentration of sodium and chloride ions in the filtrate of the macula densa.
What are Juxtamedullary nephrons?
Juxtamedullary nephrons have a glomerulus near the junction of the cortex and medulla and they have loops of Henle that penetrate deep into the medulla.
What are granule neurons?
The granule cells in the dorsal cochlear nucleus are small neurons with two or three short dendrites that give rise to a few branches with expansions at the terminals. The dendrites are short with claw-like endings that form glomeruli to receive mossy fibers, similar to cerebellar granule cells.
What are the 3 stimuli that cause the release of renin?
Mechanism of Action. Increased renin release from the juxtaglomerular cells is caused by several conditions: reduction in renal blood flow from heart failure, blood loss, hypotension or ischemia of the kidneys, sodium diuresis (excessive sodium loss in urine), and beta-adrenergic stimulation.
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