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137 Cards in this Set
- Front
- Back
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what is included in the urinary system?
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kidneys
ureters bladder urethra |
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what are the functions of the kidneys?
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filter metabolic wastes and foreign substances from blood
regulate electrolyte levels in blood synthesize and secrete hormones hydroxylate vitamin D prohormone |
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what hormones are synthesized and secreted by the kidneys?
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renin
erythropoietin |
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what is renin involved in?
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control of blood pressure and blood volume
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what is the function of erythropoietin?
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stimulates RBC proliferation and development
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how is vitamin D made into its active form?
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hydroxylated by the kidneys
(active form is calcitriol) |
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what is erythropoietin used for clinically?
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to treat anemia associated with cancer and cancer therapy
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what stimulates the conversion of inactive provitamin D to active form?
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parathyroid hormone, which promotes the synthesis of 1alpha-hydroxylase
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where is 1alpha-hydroxylase synthesized?
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proximal tubules of the kidney
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with what is the renal pelvis continuous?
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funnel-shaped expansion of the ureter continuous with the major calyces
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what is the light-staining inner region of the kidney?
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medulla
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how many medullary pyramids are in the medulla?
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8-18
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what is a renal lobe?
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medullary pyramid
associated cortex |
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what is contained in the medulla of the kidney?
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collecting ducts
loops of Henle vasa recta |
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what is a renal papilla?
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apex of the medullary pyramid where it empties into the minor calyx
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where do the minor calyces empty?
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major calyces
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what is the area cribosa?
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tip of each papilla, where it is perforated by openings of the collecting ducts
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what is the dark-staining outer region of the kidney?
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cortex
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what is contained in the cortex of the kidney?
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renal corpuscles
proximal convoluted tubules distal convoluted tubules peritubular capillaries medullary rays |
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what are medullary rays?
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groups of straight tubules and ducts that extend from the medulla into the cortex
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what are the extensions of the cortex into the medulla?
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renal columns of Bertin
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what is the connective tissue compartment of the kidney?
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renal intersitium
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what does the renal interstitium consist of primarily?
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fibroblasts
occasional macrophages |
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where are fibroblast-like cells found in the cortex of the kidney?
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between tubules and peritubular capillaries
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what do medullary interstitial cells resemble in the kidney?
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myofibroblasts
(consist of up to 20% of medullary volume) |
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what is abundant in medullary interstitial cells?
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actin filaments
lipid droplets |
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what is the functional subunit of the kidney?
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nephrons
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what are the components of a nephron?
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renal corpuscle
proximal tubule loop of Henle distal tubule |
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what are the two classifications of nephrons?
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cortical (about 80%)
juxtamedullary (about 20%) |
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which type of nephrons help to establish the interstitial osmotic gradient in the medulla?
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juxtamedullary nephrons
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why is the interstitial osmotic gradient in the medulla important?
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concentrates the urine
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what is the blood filtering part of the nephron?
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renal corpuscle
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what is a renal corpuscle composed of?
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capillary glomerulus covered by Bowman's capsule
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what is a urinary pole?
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where Bowman's space empties into a proximal convoluted tubule
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what is a vascular pole?
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where afferent arteriole enters the glomerulus and where efferent arteriole exits
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what two cell types are found in a glomerulus?
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endothelial cells
mesangial cells |
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what type of capillary is a glomerulus?
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fenestrated capillary (no diaphragms)
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from where are mesangial cells derived?
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smooth muscle cell precursors
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what are the functions of mesangial cells?
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phagocytose proteins and other molecules trapped in glomerular filtration barrier
synthesize extracellular matrix and collagen regulate blood flow by their contractile activity |
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what type of epithelium is a Bowman's capsule made from?
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parietal layer - simple squamous epithelium
visceral layer - modified simple epithelium |
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what is the visceral layer of Bowman's capsule made of?
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podocytes - foot processes wrap around glomerular capillaries
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what are filtration slits?
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spaces between interdigitations of foot processes of adjacent podocytes (which allow ions, etc. through)
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what are pedicels?
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foot processes of podocytes
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what comprises the filtration barrier in a glomerulus?
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fenestrated endothelial cells of capillaries
fused basal lamina of endothelial cells and podocytes filtration slits with diaphragms created by podocyte foot processes |
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what is the glomerular basement membrane?
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fused basal lamina of endothelial cells and podocytes in the glomerulus
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what is allowed to cross the filtration barrier?
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water
ions small molecules |
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what is contained in Bowman's space?
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urinary filtrate
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what are the three layers of the glomerular basement membrane?
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lamina rara externa
lamina rara interna lamina densa |
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which layer of the glomerular basement membrane is adjacent to the podocyte foot processes?
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lamina rara externa
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which layer of the glomerular basement membrane is adjacent to the endothelial cells?
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lamina rara interna
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which layer of the glomerular basement membrane contains heparan sulfate?
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lamina rara interna
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what is heparan sulfate?
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negatively charged proteoglycan, which contributes to the electrostatic barrier of the glomerular basement membrane
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what molecule contributes to the electrostatic barrier of the glomerular basement membrane?
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heparan sulfate
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which layer of the glomerular basement membrane is the central zone of the basal lamina?
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lamina densa
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what is the lamina densa composed of?
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meshwork of type IV collagen and laminin
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what acts as the macromolecular filter, preventing passage of large protein molecules into Bowman's space?
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meshwork of type IV collagen and laminin
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where does the proximal convoluted tubule begin?
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urinary pole of renal corpuscle
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where is nearly all glucose reabsorbed?
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proximal convoluted tubule
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what is reabsorbed at the proximal convoluted tubule?
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nearly all glucose
nearly all amino acids 80% of water 80% of Na ions |
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what type of epithelium lines the proximal convoluted tubule?
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simple cuboidal epithelium
(with numerous microvilli forming a brush border) |
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what is stained for with a PAS stain?
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carbohydrates (e.g. glycogen)
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what areas of a proximal convoluted tubule are stained in a PAS stain?
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basement membrane
brush border |
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what is numerous in the basal region of cells of the proximal convoluted tubule?
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mitochondria
infoldings of basal plasma membrane |
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why do cells of the proximal convoluted tubules require so much energy?
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active transport of sodium ions out of proximal tubule
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what is the relationship between neighboring cells of the proximal convoluted tubules?
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have extensive lateral digitations
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how do PCT cells help regulate the pH of the filtrate?
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secrete protons and organic acids into filtrate
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what creates the osmotic gradient in the interstitial fluid of the medulla?
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loop of Henle
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to what is the descending portion of the loop of Henle permeable?
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water
Na+ Cl- |
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what happens to the filtrate in the descending limb of the loop of Henle?
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isotonic filtrate loses water to the hypertonic interstitium, gaining sodium and chloride ions
(filtrate becomes hypertonic) |
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to what is the ascending limb of the loop of Henle permeable?
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Cl- is actively transported out of filtrate, and Na+ follows
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what happens in the ascending limb of the loop of Henle?
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no water is lost as the filtrate ascends
chloride ions are actively transported sodium follows chloride ions hypotonic filtrate is created |
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which part of the loop of Henle is permeable to water?
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descending limb
(ascending limb is impermeable to water) |
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what are the vasa recta renis?
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capillaries parallel to the loop of Henle, in the medulla
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which limb of the loop of Henle is the thin limb? which is the thick limb?
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thin limb - descending limb
thick limb - ascending limb |
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what is the final segment of the nephron?
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distal convoluted tubule
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with what type of epithelium is the distal convoluted tubule lined?
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simple cuboidal epithelium
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which convoluted tubule has a brush border?
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proximal convoluted tubule
(distal convoluted tubule is similar to the proximal convoluted tubule, but without the brush border in the lumen) |
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where is the macula densa?
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in the distal convoluted tubule near the afferent arteriole
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what is the function of the macula densa?
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osmoreceptors
(monitors osmolarity of tubular fluid, particularly Na+ ions) |
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how does the distal convoluted tubule make adjustments to the salt, water, and acid balance?
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secretes hydrogen into filtrate
secretes ammonium ions into filtrate reabsorbs sodium from filtrate secretes potassium into filtrate |
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what is the effect of the distal convoluted tubule?
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acidifies urine and adjusts blood sodium (and subsequently water) concentration
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to what hormone is the distal convoluted tubule responsive?
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aldosterone
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what is the effect of aldosterone?
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increases blood sodium concentration, which draws water out of the filtrate
(increases blood volume, increases blood pressure) |
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what is the target of aldosterone?
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cells of the distal convoluted tubule
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what is the role of the collecting ducts?
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connects nephrons to ureters and participates in electrolyte and fluid balance
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what is anti-diuretic hormone (ADH)?
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hormone which makes collecting tubules permeable to water
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what happens in the presence of ADH?
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collecting tubules are permeable to water
hypertonic (concentrated) urine |
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what happens in the absence of ADH?
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collecting tubules are impermeable to water
hypotonic (diluted) urine |
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into what do the collecting ducts empty?
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minor calyx through the area cribosa
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what is another name for the collecting ducts?
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collecting ducts of Bellini
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at which pole of a renal corpuscle can the juxtaglomerular apparatus be found?
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vascular pole
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what is included in the juxtaglomerular apparatus?
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juxtaglomerular cells
macula densa extraglomerular mesangial cells |
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what are juxtaglomerular cells?
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modified smooth muscle cells in the kidney, with numerous secretory granules, which secrete renin
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in response to what do juxtaglomerular cells secrete renin?
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low blood pressure
low blood volume low blood sodium levels |
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what cells secrete renin?
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juxtaglomerular cells
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what is the path of blood in the kidney?
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renal artery -> interlobar artery -> arcuate arteries -> interlobular arteries -> afferent arteriorles -> glomerulus -> efferent arterioles
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what type of arteries travel along the cortex-medulla border of the kidneys?
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arcuate arteries
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where do the interlobular arteries travel?
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between the medullary rays
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what arteries supply each glomerulus?
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afferent arterioles
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what is a portal blood system?
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blood travels through two sets of capillaries before returning to the heart
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what carries blood away from the glomerulus?
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efferent arteriole
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into what does efferent arteriole branch?
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peritubular capillaries
vasa recta |
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what surrounds the proximal and distal tubules in the cortex?
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peritubular capillaries
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what surrounds the loops of Henle, descending into the medulla?
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vasa recta
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what is another name for Wilms tumor?
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nephroblastoma
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what is the 4th most common malignancy in children?
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wilms tumor (nephroblastoma)
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what characterizes Wilms tumor?
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recognizable attempts to recapitulate different stages of nephrogenesis
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what classic triphasic combination of cell types is observed in the vast majority of wilms tumor lesions?
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blastemal
stromal epithelial |
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what is included in the excretory passages of the kidney?
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calyces
renal pelvis ureters bladder urethra |
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what composes the three-layers of the wall of the kidney's excretory passages?
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mucosa (transitional epithelium with lamina propria)
muscularis adventitia |
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what propels urine toward the bladder in the ureter?
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peristaltic contractions of the 2-3 layers of smooth muscle in the muscularis
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what type of epithelium is present in the ureter?
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thick transitional epithelium
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what composes the wall of the urinary bladder?
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transitional epithelium
lamina propria three-layered muscularis |
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what are fusiform vesicles?
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unique cytoplasmic organelles of transitional epithelium which exocytose onto the cell membrane to elongate its apical surface (to distend)
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how do transitional epithelium cells appear in a relaxed state?
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superficial cells bulge into the lumen and contain fusiform vesicles
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how do transitional epithelium cells appear in a distended state?
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superficial cells are flattened and without fusiform vesicles
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in a transitional epithelium cell, what folds inward during relaxation?
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plaques
(stiff, rigid areas of the plasma membrane) |
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how many layers are in the muscularis of the bladder?
the urethra? |
bladder - 3
urethra - 2 |
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where is the external urethral sphincter? what is its function?
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membranous urethra
(originating at the pubic ramus and inserting into the median raphe) fcn. - voluntary control of urine flow |
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where are glands of littre?
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glands that branch off (or in lamina propria) of the urethra of males
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what is the function of glands of littre?
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secrete mucous into the semen
(mostly in penile/spongy urethra) |
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what are the three divisions of the male urethra?
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prostatic urethra
membranous urethra penile/spongy/cavernous urethra |
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where is the prostatic urethra?
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in the prostate gland
(widest portion) |
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where is the membranous urethra?
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between apex of prostate and bulb of urethra (in deep perineal pouch)
(shortest, least dilatable, narrowest part) |
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where is the spongy/penile urethra?
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contained in corpus spongiosum, from bulb to external orifice
(longest part) |
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what epithelium lines the male urethra?
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prostatic - transitional epithelium
membranous - pseudostratified columnar epithelium penile - stratified squamous epithelium |
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what epithelium lines the female urethra?
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stratified squamous epithelium along the entire length
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what stimulates the release of renin?
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decreased blood pressure
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how is decreased blood pressure sensed by macula densa cells?
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sensed in macula densa as decreased glomerular filtration rate and decreased sodium concentration in the DCT
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how is decreased blood pressure sensed by juxtaglomerular cells?
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directly
(act as mechanoreceptors) |
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what does renin interact with?
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angiotensinogen released by liver
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to what is angiotensinogen converted? by what enzyme?
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angiotensin I
protease activity of renin |
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what is the function of angiotensin I?
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precursor for angiotensin II
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what enzyme functions to convert angiotensin I to angiotensin II?
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angiotensin converting enzyme (ACE)
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where is angiotensin I converted to angiotensin II?
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capillaries of the lungs (by angiotensin converting enzyme or ACE)
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what are the effects of angiotensin II?
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direct action on renal tubular cells of DCT (increases Na and water uptake)
stimulates aldosterone release from adrenal cortex (increases Na and water uptake in DCT) constricts peripheral blood vessels |
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what is the overall function of angiotensin II?
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increase blood pressure
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