The main function of the medulla is to regulate concentration of the urine. The urine flows from the collecting ducts into the renal calyces and pelvis, which undergoes unidirectional peristaltic movements to allow drainage of the urine into the downstream ureter and bladder.
What does the renal medulla produce?
Renal medullaFMA74268Anatomical terminology
How does the medulla regulate the concentration of urine?
In the presence of ADH, the medullary collecting ducts become freely permeable to solute and water. As a consequence, the fluid entering the ducts (en route to the renal pelvis and subsequent elimination) acquires the concentration of the interstitial fluid of the medulla; i.e., the urine becomes concentrated.
What is the difference between the renal cortex and medulla?
It is divided into smaller sections called as renal pyramids. The difference between renal cortex and renal medulla is, the renal cortex is the outer portion of the kidney whereas renal medulla is the innermost part of the kidney.What is inside the renal medulla?
The renal medulla contains the renal pyramids, where urine formation takes place. Urine passes from the renal pyramids into the renal pelvis. This funnel-shaped structure occupies the central cavity of each kidney and then narrows as it extends out to join the ureter. Urine drains from the renal pelvis into the ureter.
What is the function of the renal pelvis?
The kidney pelvis acts like a funnel, collecting the urine produced in the kidney and leading to a central “stem,” the ureter.
Why is the renal medulla darker?
It is darker than its underlying renal medulla because it receives over 90% of the kidney blood supply. … The renal medulla appears striped, as it contains vertical nephron structures (tubules, collecting ducts). It consists of renal (medullary) pyramids separated by projections of the renal cortex (renal columns).
What is the function of the osmotic gradient found in the medulla of the kidney?
In the inner medullary collecting ducts it increases both water and urea permeability, which allows urea to flow passively down its concentration gradient into the interstitial fluid. This adds to the osmotic gradient and helps drive water reabsorption.What is the importance of the perirenal fat capsule that surrounds the kidney?
Perinephric fat, also known as perirenal fat or the adipose capsule of the kidney, is a layer of fatty material that surrounds the kidneys. It plays an important role because it helps to cushion and protect the kidneys. Trace the pathway a creatinine molecule takes from a glomerulus to the urethra.
What creates the osmotic gradient in the renal medulla?This osmotic gradient is formed by the accumulation of solutes, primarily NaCl and urea, in the cells, interstitium, tubules, and vessels of the medulla (4–6).
Article first time published onWhy is reabsorbed water rapidly removed from the medulla?
Reabsorbed water is removed efficiently by the vasa recta in the renal medulla. Because these blood vessels also are arranged in a hairpin loop, minimal loss of medullary interstitial solute occurs with water removal.
Why is the medulla salty?
The body has a clever mechanism to conserve water levels, it creates a strong salt concentration in the medulla of the kidney via the Loop of Henle. This means that water can be drawn out of the tube later on by osmosis and taken away by the blood.
Why medulla has a striped appearance?
The medulla consists of a number of medullary pyramids, named because of their triangular shape. These are striped in appearance because they contain microscopic coiled tubes called nephrons, the functional unit of the kidney . … The collecting ducts merge at the base of the pyramids to form the renal papilla.
Why is renal medulla sensitive to hypoxic damage?
We identify seven factors that render the kidney susceptible to hypoxia: (1) the large metabolic demand imposed by active reabsorption of sodium; (2) limitations on oxygen delivery to cortical tissue imposed by the density of peritubular capillaries; (3) the poor capacity for angiogenesis in the adult kidney; (4) the …
Which part of the nephron can be found in the medulla of the kidney?
Different sections of nephrons are located in different parts of the kidney: The cortex contains the renal corpuscle, proximal, and distal convoluted tubules. The medulla and medullary rays contain the loops of Henle and collecting ducts.
What does the renal pelvis contain?
The renal pelvis contains the hilium. The hilum is the concave part of the bean-shape where blood vessels and nerves enter and exit the kidney; it is also the point of exit for the ureters—the urine-bearing tubes that exit the kidney and empty into the urinary bladder.
What is Intrarenal pelvis?
The postulate is advanced that when the pelvis of the human kidney is situated entirely within the renal parenchyma (intra-renal pelvis), it becomes an important predisposing factor in hypertension.
What is the primary role of the perirenal fat capsule?
Each kidney is held in place by connective tissue, called renal fascia, and is surrounded by a thick layer of adipose tissue, called perirenal fat, which helps to protect it. A tough, fibrous, connective tissue renal capsule closely envelopes each kidney and provides support for the soft tissue that is inside.
What is ultrafiltration in the kidney GCSE?
Ultrafiltration is a process in the kidney by which urea, salt, water and glucose etc. is extracted from the blood. When blood passes through the top of the nephron, it enters a structure called the glomerulus which is a network of tiny capillaries.
What is Perinephric fat stranding?
This type of imaging is often used for diagnosing pyelonephritis; some doctors believe that a condition called perirenal fat stranding (PFS), in which swelling of the fat around the kidneys is visualized on CT, is a characteristic finding of pyelonephritis.
Why does osmolarity increase in the medulla?
As the ducts descend through the medulla, the osmolarity surrounding them increases (due to the countercurrent mechanisms described above). If aquaporin water channels are present, water will be osmotically pulled from the collecting duct into the surrounding interstitial space and into the peritubular capillaries.
What creates the osmotic gradient in the renal medulla quizlet?
A vertical osmotic gradient established in the renal medulla is the cornerstone of the process. ->This vertical gradient must be both established and maintained. The loop of Henle is responsible for ESTABLISHING the gradient and the vasa recta MAINTAINS the gradient.
What helps to produce the concentration gradient in the renal medulla?
The Loop of Henle is the countercurrent multiplier that is responsible for maintaining the concentration gradient in the medulla.
What is the meaning of osmotic gradient?
The osmotic gradient is the difference in concentration between two solutions on either side of a semipermeable membrane, and is used to tell the difference in percentages of the concentration of a specific particle dissolved in a solution.
What structure does the filtrate flow into after the renal corpuscle?
The correct path of filtrate through a nephron starts in the renal corpuscle, which is comprised of the glomerulus and Bowman’s capsule. Filtrate then passes through the proximal convoluted tubule, where the majority of reabsorption takes place.
How does the renal countercurrent multiplier mechanism allow the creation?
How does the renal countercurrent multiplier mechanism allow the creation of a concentrated urine? A) By concentrating NaCl in the renal medullary interstitium, it allows water to be reabsorbed from the collecting ducts when vasopressin is present.
What is reabsorbed in the kidney?
Most of the reabsorption of solutes necessary for normal body function, such as amino acids, glucose, and salts, takes place in the proximal part of the tubule. This reabsorption may be active, as in the case of glucose, amino acids, and peptides, whereas water, chloride, and other ions are passively reabsorbed.
Where does renal absorption and secretion occur?
This reabsorption occurs in the PCT, loop of Henle, DCT, and the collecting ducts while the majority of secretion occurs in the PCT and DCT (Table 25.5 and Figure 25.5. 1). Various portions of the nephron differ in their capacity to reabsorb water and specific solutes.
What is the osmolarity of the fluid in the interstitial space of the renal medulla?
The interstitial osmotic pressure is 300–500 mOsm/l, caused by sodium pumped from the ascending tubule to the interstitial space. The ascending tubule content is of decreasing osmolarity, caused by the pumping process that simultaneously increases osmolarity in the interstitial space.
Why is it important that the medulla is hypertonic?
The osmolality of the mammalian kidney medulla is very high. … Salt and urea are the major solutes in the renal medullary interstitium. Unfortunately, high salt (hypertonicity) causes DNA damage and cell death. In response, the renal medullary cells adapt to the hypertonicity by accumulating compatible osmolytes.
What is renal cortex?
The renal cortex is the outer part of the kidney. It contains the glomerulus and convoluted tubules. The renal cortex is surrounded on its outer edges by the renal capsule, a layer of fatty tissue. Together, the renal cortex and capsule house and protect the inner structures of the kidney.
