Urinary System

each kidney is surrounded by three protective layers of connective tissue: the renal fascia, adipose capsule, renal capsule.

The renal capsule surrounds the outer region of the kidney called the ____ ____. the cortex contains many filtration units called ____, which have tubules that dip into the interior region called the ______. the tubules in the medulla run parallel to each other and form striped cone shaped masses of tissue called _____ ____. a cavity called the ___ ___ contains the basin-like ____ ___, which funnels the urine into the ureter. the _____ is the concave region of the kidney artery, which branches into smaller and smaller arteries until the blood reaches a tuft of capillaries called the ________. here the blood is filtered before leaving the kidney through a network of veins that merge into the renal vein.

renal cortex, nephrons, medulla, medullary pyramids, renal sinus, renal pelvis, hilum, glomerulus

The renal cortex is the outer portion of the kidney, and it is the site of ___________(nonspecific filtration of blood under high pressure). it is also responsible for the majority of the reabsorption of water. the cortex is very vascular and has a granular appearance due to the presence of nephrons. the renal corpuscles and the convoluted tubules of the nephrons are within the cortex and foming the _____ ____, but the loops of henle extend into the adjacent region known as the renal medulla. the thick, straight portions of the proximal and distal tubules, as well as the collecting ducts, from _____ ___ that begin in the cortex and run perpendicular to the capsule. about 85% of nephrons are ___ ____ and have short loops of hence that extend only slightly into the medulla. the remaining 15% are called _____ ____ and have longer loops that extend even deeper. extensions of the cortex called ____ ____ dip down in between the rental pyramids of the medulla

ultrafiltration,cortical labyrinth, medullary rays, cortical nephrons, juxtamedullary nephrons, renal columns

the_____ ____ is the inner part of the kidney, and it continues the reabsorption of water and salts began in the cortex. These substances enter the peritubular capillaries that are associated with the nephrons. Any filtrate that is not reclaimed by the circulatory system will leave as urine

adrenal medulla

the medulla contains cone-shaped regions of tissue called ____ ____ that are separated by ____ ___. the tips of the pyramids are oriented toward the pelvis of the kidney, and the bases face the cortex. the ____ ____ contain tubules that transport renal filtrate from the renal cortex to the apex of the pyramids. at the apex is a structure called the ____ ____ that contains ducts that allow the processed filtrate(now called urine) to pass out the medulla to collecting chambers called calyces. from here the urine passes through the renal pelvis, through the ureter, and finally into the bladder

renal pyramids, renal columns , renal pyramids, renal papilla, calyces

The nephron is the functional unit of the kidney. each kidney has over a million of these microscopic structures, and each one consists of two main parts: the ____ ____(which filters the blood), and the ______ _____(which collects and concentrates the filtrate) the renal corpuscle consists of a cup-shaped structure called the_____ ____ that wraps partially around a cluster of capillaries called the ______.The renal tubule is a looping canal that is continuous with Bowman’s capsule . it consists of different regions that differ in structure and function. The ____ ___ ___ begins at Bowman’s capsule and then plunges into the medulla, forming a u-shaped called the l_____ ____ ____. it then becomes the ____ ____ ___, which is continuous with the ____ ____. the collecting duct is typically considered a separate structure and not part of the nephron

renal corpuscle, renal capsule Bowman’s capsule, glomerulus, proximal convoluted tubule, loop of henle, distal convoluted tubule, collecting duct

each renal corpuscle consists of a ______ and a _____ ___ . the glomerulus is a tangled network of blood capillaries that occupies Bowman’s capsule. these fenestrated capillaries are lined with a thin layer of epithelial cells. an ____ ____ takes blood to the glomerulus and an ____ ____ takes it away. the smaller diameter of the efferent arteriole increases pressure within the glomerulus, which is required for ultrafiltration. _____ ____ contract to regulate blood flow, and also support the capillary network

glomerulus, bowman’s capsule, afferent arteriole, efferent arteriole, mesangial cells

Bowmans capsule is a cup-like structure at the closed end of the renal tubule that encloses the glomerulus. it has an outer layer of epithelial cells that form the parietal layer, and it has a visceral layer of ______ with processes called ____ that wrap around the capillaries . gaps between the pedicels(filtration slits) allow the passage of tiny molecules and ions. together, the endothelial cells of the capillaries, the basement membrane, and the pedicels make up the _____ _____ fluid from the blood leaves the fenestrated capillaries and passes through the filtration membrane and collects in the _____ ____(the cavity between the two layers of Bowmans capsule). from here the filtrate enters the renal tube

podocytes, pedicels, filtration membrane, Bowman’s spaces

the renal tubule is divided into three continuous regions: the proximal convoluted tubule, the loop of Henle, and the distal convoluted tubule. The _____ ____ ____ extends from Bowmans capsule, and this coiled tube is characterized by cuboidal cells with dense microvilli that aid in reabsorption and secretion. there are only sparse microvilli in the rest of the tubule. the middle, hairpin-shaped portion of the renal tubule is called the _____ ___ ____, and it maintains a relatively high solute concentration in the medulla, which in turn assists in the reabsorption of water. the loop consists of a descending limb(which absorbs water) that plunges into the medulla, a U-turn that curves back toward the cortex, and an ascending limb(which reabsorbs ions). the ascending limb widens into a thick portion composed of larger epithelial cells. The loop is lined with simple squamous epithelial cells, with the exception of the thick ascending limb which is lined with simple cuboidal . this limb becomes the ____ ____ ___(also lined with cuboidal cells) , which is involved in absorption and secretion, but not to the extent of the proximal convoluted tube(it is also shorter in length)

proximal convoluted tubule ,loop of henle,distal convoluted tubule

The collecting duct is the final site of reabsorption in the kidney, and it is shared by multiple nephrons. the distal tubule empties filtrate into the collecting duct, which merges with other collecting tubules to form collecting duct. collecting tubules are lined with simple cuboidal epithelium, but these cells elongate to form columnar cells as they get closer to the duct. some of these cells are ____ ___, which reabsorb sodium ions and water(under ADH and aldosterone control). other cells are _______ _____ and they play an important role in acid-base balance and the reabsorption of sodium ions. both these cells can also be found toward the end part of the distal tubule, but there are fewer microvilli than in the collecting duct. the filtrate that passes through the collecting duct enters the minor calyces at the apex of a medullary pyramid

principal cells, intercalated cells

The formation of urine begins with the _____ ____. this nonspecific filtration is driven by the hydrostatic pressure of blood. this pressure is higher than in other capillaries because the efferent arterioles that exit the glomerulus have a smaller diameter than the afferent arterioles that enter. water and small solutes from the blood are forced through fenestrations in the capillaries, leaving behind larger particles. the fluid must pass through 3-layered filtration membrane before entering Bowmans space as renal filtrate. The first layer is the _____ ____ of the capillaries. fenestrations in the capillaries prevent the passage of blood cells. the second layer is the _____ _____ which excludes plasma proteins such as albumin. the third layer is the ____ ____ of the Bowman’s capsule. small filtration slits between the podocytes allow only the smallest of particles to pass. the concentration of a solute in the glomerular filtrate is the same as the concentration in the blood.(1/5 of the blood filtered)

glomerular filtration, endothelial lining, basement membrane, visceral lining

_______ removes solutes from the blood and adds them to the filtrate, while ________ removes solutes from the filtrate and returns them to the blood. solutes are moved by either primary active transport, secondary active transport, or diffusion, water is reabsorbed by osmosis.

secretion, reabsorption

proximal convoluted tubule role in secretion and reabsorption

secretion: H+, creatinine, NH4+, drugs, toxins(active transport)

role in reabsorption: main site of reabsorption in the kidney; 60-70% of the volume of filtrate is reclaimed in the PCT. glucose, amino acids, vitamins, NA+, CL-, K+, CA2+, mg2+, bicarbonate, phosphate, water, urea

loop of henle-descending limb role in secretion and reabsorption

role in secretion: urea

role in reabsorption: water

loop of henle-ascending limb role in secretion and reabsorption

secretion; N/A

reabsorption : Na+,Cl-,K+,mg2+,Ca2+

distal convoluted tubule role in secretion and reabsorption

secretion: K+, H+

Role in reabsorption: CL-,CA2+,NA+,water(variable permeability-opening of NA+, channels is dependent on aldosterone)

collecting duct role in secretion and reabsorption

secretion: K+,H+

reabsorption: urea, bicarbonate, NA+, water(variable permeability— dependent on aldosterone and ADH)

The concentration of urine is influenced by the high solute concentration of the _______, and the _____ that control the permeability of the distal convoluted tubule and collecting duct

medulla, hormones

the ____ ____ describes the use of active transport to move solutes out of the ____ _____ _____(which is impermeable to water) into the _____ ______. the somatic gradient that is created causes water to diffuse out of the _____ ____(with is permeable to water), concentrating the filter. the recycling of urea also helps to maintain a high _____ ____. the descending loop of henle and the collecting duct are both permeable to urea, but the descending limb and the distal tubule are not. urea enters the descending loop from the interstitium, and travels through the renal tubule to the collecting duct , where it reenters the interstitium

countercurrent, ascending loop of henle, medullary interstitium, medullary osmolarity

a _____ ____ in the loop of henle is responsible for the generation of an osmotic gradient in the medulla that promotes the reabsorption of water. the _____ ____ is permeable to water but not solutes. the ____ ____ is permeable to water to solutes but not water. NA+, CL- and the other ions are actively transported from the ascending limb into the medullary interstituim. the concentration gradient causes water to leave the descending limb by osmosis, which increases the concentration of the filtrate in the descending limb. As the citrate moves up the ascending limb, ions are actively absorbed, raising the solute concentration in the medulla. This positive feedback loop is known as the _____ _____ _____because it multiplies the concentration of the interstitial fluid as a result of the functional differences between the two limbs.

a countercurrent system, descending limb, ascending limb,

countercurrent multiplier mechanism

_____ _____ ___, in which the hypertonicity of the medulla is maintained(not generated) by the countercurrent flow of blood in the vas recta. as the blood descending part of the vasa recta passes the ascending limb, it picks up ions that left the filtrate. as blood in the ascending vasa recta passes the descending limb, most of the ions diffuse back into the medulla

countercurrent exchange system

A _____ is a tubular organ that delivers urine from the kidney to the bladder for storage. the ____ ___(final sites of reabsorption) empty urine into the ureter, and both gravity and _____ move the urine into the bladder(can carry 600ml the urge to pee comes at 150ml). the ureters, bladder, and superior portion of the urethra are lined with ____ ____ ____ that allows expansion. when the organ becomes distended, the stretched epithelium appears to have fewer cell layers.

ureter, collecting ducts, peristalsis, transitional epithelial tissue

urine is tired in the bladder until contraction of the ____ ____(the smooth muscle within the bladder) forces urine into the _____. contractions of the bladder is controlled by the ______ _____ ____. ______ receptors in the bladder send impulses to the sacral region of the spinal cord. impulses are then sent along _____ neurons to the bladder, telling it to contract. a circular smooth muscle called the _____ _____ ____relaxes. if the timing is right then the voluntary ____ ___ ____ relaxes. urine flows from the bladder, through the urethra, and out of the body in a process called ______

detrusor muscle, urethra, parasympathetic nervous system, stretch, efferent, internal urethral sphincter, external urethral sphincter, micturition

the _____ ___ ___ is found between the bladder and the urethra. It consists of ____ ____ of the bladder(the detrusor muscle is other name). the _____ ____ ___ keeps the IUS contracted until micturition reflex is triggered. the _____ ____ ___(EUS), which is made of ___ ___ and under control of the ____ ____ . voluntary contraction of __ muscles can increase the rate of flow by compressing the bladder

internal urethral sphincter(IUS), smooth muscle, sympathetic nervous system, external urethral sphincter, skeletal muscle, somatic nervous system, abdominal

when ________ detect an increase in blood osmolality, or when ______ detect a decrease in blood pressure, the pituitary gland secretes _____ ____(ADH). ADH stimulates the reabsorption of water in the kidney so that less water is excreted in the urine. this increases the volume and pressure of the blood

osmoreceptors, baroreceptors, antidiuretic hormone

the _____ _____ ____ ___ is another mechanism by which blood pressure is regulated. when granular juxtaglomerular cells of the afferent arterioles of the kidneys detect a drop in blood pressure, they secret an enzyme called ____. renin interacts with a plasma protein called _________, producing ________ . As angiotensin enters the capillaries of the lungs, it is acted on by another enzyme that converts it to _______ _____. this hormone raises blood pressure by promoting vasoconstriction and stimulating the adrenal cortex to release ________ (which increases the reabsorption of sodium increasing the water reabsorption, causing the blood volume and pressure to increase

renin-angiotensin-aldosterone(RAAS), Renin, angiotensinogen,angiotensin I, ,angiotensin II, aldosterone

when osmoreceptors in the ______ detect an increase in osmolality, signals are sent to the pituitary gland to release ADH. ADH causes the ____ ____ in the kidneys to be more permeable to water, and water crosses the epithelium from the urine into the interstitium where it is returned to the blood. as a result, the blood osmolality ______, and urine osmolality ______

hypothalamus, collecting ducts, decreases, increases

the kidneys are key players in the maintenance of blood PH, which must be kept within a narrow range of _____ and _____. this is achieved by regulating the ratio of hydrogen ions to bicarbonate ions(higher pH= _____ hydrogen ions). ____ ___in the body such as the phosphate, protein, and bicarbonate systems are in place to resist changes in H+ concentration which increases PH. Increasing the rate of respiration ______ the concentration of H+.(vice versa). the response from the kidney is slower but lasts much longer. as blood PH decreases H+ ions are excreted by the _____ _____ via urine and bicarbonate ions are retained. the ______cells of the late distal tubule and collecting duct can also generate new bicarbonate ions. The kidneys lower PH by ______ H+ and secreting _______ ___

7.35, 7.45, more, buffer systems, decreases, renal tubules,intercalated, reabsorbing, bicarbonate ions

nitrogen-containing wastes such as ammonia, urea, uric acid, and creatinine are excreted in urine. ________ is a toxic base that is formed during the breakdown of amino acids. Enzymes in the liver convert it to a less toxic form called _______, there is a high concentration of urea in the medulla because the collecting ducts are permeable to it. much of the urea enters the interstium, and it is then reinsured in the descending loop of henle. urea is the most abundant nitrogenous waste product in urine, but since its mostly recycled, only a small amount is excreted with urine. the high concentration of urea in the interstitium is helpful because it promotes the reabsorption of water. ______ ___ Is another nitrogenous waste that is excreted in the urine. it is formed as a byproduct of the catabolism of purine nucleotides, and most of it is reabsorbed in the proximal tubule by active transport. like use, only a small percentage is excreted. _______ is produced in the muscles as a byproduct of the metabolism of creatine phosphate. it is filtered by the kidney and excreted by the kidney(creatinine is never reabsorbed)

Ammonia, urea, uric acid, creatinine