Flashcards in 25 1-7 Deck (38):
Structures that compose the urinary system?
Kidneys, ureters, urinary bladder, urethra
Function of ureters?
Transport urine from kidneys to the urinary bladder
Function of bladder?
Stores urine (up to 1L)
Function of Urethra?
Eliminates urine from the body
Function of kidneys? 8
Filtration of plasma, reabsorption of useful chems, secretion, Concentration of urine.
Regulation of blood plasma volume, plasma osmolarity, BP.
Regulation of ion concentration (esp. Na+/K+/Ca2/HCO3-/H+) and pH balance.
Secretion of renin that activates hormonal mechanisms to ctrl BP/electrolytes.
Produce and secrete EPO.
Formation of calcitriol (calcium homeostasis).
Gluconeogenesis - can form glucose in extreme starvation.
Conservation (of water, nutrients).
Lie retroperitoneal in the superior lumbar region.
Size of a bar of soap
Gross anatomy, exterior of kidney? 5
A concave medial surface that has a renal hilum-->renal sinus where blood vessels/nerves/lymph vessels lie.
Outer layer - Surrounded by renal fascia/dense irreg. which anchors kidney and adrenal glands to surrounding structures.
Perirenal fat pad surrounds and cushions the kidney.
Fibrous capsule/dense irreg. directly adheres to kidney to maintain shape/protect/keep infections out.
Adrenal glands sit on top.
Gross anatomy, interior of kidney?
Renal cortex, Renal medulla, renal pelvis.
Renal columns are extensions of the cortex projecting into medulla.
Trace the blood supply through the kidney.
Aorta, renal artery,,, Afferent arteriole, glomerulus, efferent arteriole, peritubular capillaries,,, renal vein, Inf. VC
Importance of the afferent and efferent arterioles?
Maintains the high pressure in the glomerulus that is needed for filtration.
Which structures in the kidney are innervated by the sympathetic nervous system?
The renal plexus (offshoot of celiac) regulates renal blood flow by adjusting the diameter of renal arterioles (aff and eff) via symp innervation.
Symp also innervates the juxtaglomerular apparatus.
Functional/structural unit of urinary system?
Nephron. They carry out processes to form urine. 1.25 million per kidney.
Anatomy of a nephron?
Consists of a renal corpuscle and renal tubule and are connected to collecting ducts.
Order of nephron structures?
Renal corpuscle (glomerulus and capsule surrounding it), PCT, Loop of Henle, DCT, collecting duct.
What does the renal corpuscle consist of?
glomerulus (ball of caps), bowman's/glomerular capsule (encases the glomerulus),
Structure: Fenestrated endothelium.
Function: Filtration of plasma (no proteins/cells/ pass) into filtrate. Most filtrate (99%) is reabsorbed.
Bowman's capsule stucture/function?
Structure: Parietal layer and visceral layer that clings to glomerular caps. Parietal is simple squamous. Visceral layer is highly modified, branching epithelial cells, podocytes.
Function: Parietal - shape/structure. Visceral layer - filtration.
What does the renal tubule consist of?
1.2" long, 3 major parts: PCT, Nephron loop, DCT. Empty into collecting ducts.
PCT, Proximal convoluted Tubule structure/function?
Structure: cuboidal epithelium, apical surfaces have microvilli
Function: reabsorption - the brush border increases the surface area/capacity to reabsorb water and solutes
Mass reabsorber, 2/3 h20, 100% glucose/aa
Nephron loop/loop of henle structure/function?
Structure: descending/ascending limbs. Proximal descending limb is cuboidal/microvilli like the PCT, rest of descending limb is simp squam changing to cuboidal or columnar in the ascending limb.
Function: concentration of urine
DCT, Distal convoluted tubule structure/function?
Structure: Cuboidal, almost no microvilli
Function: secretion (some concentration of urine)
Collecting duct structure/function?
Structure: Principal cells with microvilli responsible for maint. water/NA+ balance. Intercalated cells - cuboidal with abundant microvilli.
Function: receive filtrate, maintain acid-base balance, concentration of urine
C+C Cortical and Juxtamedullary nephrons 5
NUMBER 85% 15%
LOOPS OF HENLE short long
CAPILLARY peritubular vasa recta
SPECIALTY reabsorption conc. of urine
LOCATION Cortex except loops Cortex-medulla junction
Types of nephron capillary beds?
Glomerulus, peritubular capillaries, vasa recta
Bundle of long straight vessels that arise from the efferent arterioles serving juxtamedullary nephrons. Intertwine with the loop of henle.
Play a role in forming contrated urine.
Arise from efferent arterioles draining the glomerulus, cling to renal tubules of cortical nephron.
Absorb solutes and water from the tubules.
Low pressure because they arise from high-resistance efferent arterioles.
Location: Region where distal portion of ascending limb of loop of henle lies against the afferent arteriole feeding the glomerulus and the tissue is modified here.
Structure: Has three populations of cells: macula densa, granular, mesangial
Function: regulates filtrate formation and blood pressure
In DCT (adjacent to the granular cells).
These are chemoreceptors that monitor NaCl content of filtrate.
Send paracrine signal ATP to vasoconstrict, NO to vasodilate.
In arteriolar walls, enlarged smooth muscle cells that synthesize and secrete renin when stimulated by stretch or sympNS.
Act as Mechanoreceptors
Lie between the arteriole and tubule cells and have both phagocytic and contractile roles. May change surface are available for filtration.
Describe the structure of the filtration membrane.
Lies between the blood and the interior of the glomerular capsule and allows passage of water and solutes.
Capillary endothelium/Basement membrane/Visceral layer of Bowman's capsule
Composed of: Fenestrated capillary endothelium of glomerulus (allows plasma and dissolved substances to pass.)
Basement membrane of glomerulus (restricts plasma proteins, has glycoproteins that give a negative charge and repels anions)
Visceral layer of glomerulus capsule (specialized cells called podocytes with foot-like processes (pedicels) that form filtration slits which allow filtrate to enter the capsular space. If any macromolecules make it thru they are stopped by slit diaphragms that run from filtration slit to filtration slit.)
Glomular filtration is?
Passive, nonselective process in which hydrostatic pressure forces fluids and solutes through a membrane.
Takes place in the renal corpuscle and produces a cell and protein fee filtrate.
Tubular reabsoption is?
The process of selectively moving substances from the filtrate back into the blood.
Takes place in the renal tubules (PCT) and collecting ducts. Reclaims 2/3 H2o, 100% glucose/AA/Vit/Min
Tubular secretion is?
The process of selectively moving substances from the blood into the filtrate.
Occurs along the length of the tubule and collecting duct (PCT and CD).
Concentration happens in?
Loop, DCT, collecting duct of juxtamedullary caps
Innermost layer of filtration membrane?
Fenestrated capillary endothelium of glomerulus
(allows plasma and dissolved substances to pass.)
Middle layer of filtration membrane?
Basement membrane of glomerulus
(restricts plasma proteins, has glycoproteins that give a negative charge and repels anions)