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40 Cards in this Set
- Front
- Back
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Organs of the Urinary system
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kidneys
ureters bladder urethra |
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Functions of urinary system
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Regulation of:
blood ionic composition blood pH, osmolarity, & glucose blood volume BP release of erythropoietin and calcitriol excretion of wastes & foreign substances |
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What 2 regions make up the parenchyma of the kidney?
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Renal cortex
Renal medulla |
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What does the renal medulla consist of?
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Renal Pyramids
Renal columns |
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What does a renal lobe consist of?
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Renal Pyramid
overlying area of renal cortex one half of each adjacent renal column |
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What are the 1 million functional units of the kidney called?
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Nephron
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Where is urine formed?
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Nephrons
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What is the path of urine drainage?
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Collecting duct
Papillary duct in renal pyramid Minor calyx Major calyx Renal pelvis Ureter Bladder |
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What nerves regulate blood flow and renal resistance by altering arterioles?
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Sympathetic vasomotor nerves
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True or False
Kidney is abundantly supplied with blood vessels and recieves 25% of resting cardiac output |
True
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What is the path of blood flow in the kidneys?
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Afferent arteriole
Glomerulus Efferent arteriole Vasa recta Peritubular capillaries |
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What 2 parts does a nephron consist of?
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Renal corpuscle
Renal tubule |
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Renal corpuscle
consists of? site of? |
Site of plasma filtration
Consists of glomerulus and Bowman's capsule |
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What are the 3 main sections of the renal tubule?
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Proximal convoluted tubule
loop of Henle dips down into medulla Distal convoluted tuble |
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Flow of fluid through a cortical nephron?
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Glomerular capsule
Proximal convulated tubule Desending limb of the loop of Henle Ascending limb of the loop of Henle Distal convoluted tubule |
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Where are cortical nephrons?
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Renal corpuscles are in outer cortex and loops of Henle lie mainly in cortex
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Flow of fluid through a juxtamedullary nephron?
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Glomerular capsule
PCT Descending limb of loop of Henle Thin ascending limb of loop of Henle Thick ascending limb of loop of Henle DCT |
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Where are juxtamedullary nephrons?
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Renal corpuscles are close to medulla and long loops of Henle extend into deepest medulla enabling excretion of dilute or concentrated urine
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True or False
Number of nephrons remains constant from birth? |
True
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Nephrons and collecting ducts 3 basic processes are?
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glomerular filtration
tubular reabsorption tubular secretion |
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the formula for the rate of excretion
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its rate of filtration plus its rate of secretion minus its rate of reabsorption
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What produces glomerular filtration?
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Blood pressure
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Net Filtration Pressure =?
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NFP= GBHP -(CHP + BCOP)
normally should = 10 mm Hg |
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Renal Autoregulation of GFR
What 2 mechanisms maintain a constant GFR despite changes in arterial BP? |
Myogenic mechanism
Tubuloglomerular feedback |
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How does the myogenic mechanism work?
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1.Systemic increases in BP, stretch the afferent arteriole
2. Smooth muscle contraction reduces the diameter of the arteriole returning the GFR to its previous level |
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How does the tubuloglomerular feedback work?
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1. Elevated systemic BP raises the GFR so that fluid flows too rapidly through the renal tubule & Na+, Cl- and water are not reabsorbed
2. Macula densa detects that difference and releases a vasoconstrictor from the juxtaglomerular apparatus 3. Afferent arterioles constrict and reduce GFR |
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Hormonal Regulation of GFR
What 2 hormones help regulate GFR? |
Atrial natriuretic peptide (ANP)
Angiotensin II |
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How does the atrial natriuretic peptide work in maintaining GFR?
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Stretching of the atria causes hormonal release
This relaxes glomerular mesangial cells increasing capillary surface area and increasing GFR |
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How does Angiotensin II work in maintaining GFR?
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Potent vasoconstrictor that narrows both afferent and efferent arterioles reducing GFR
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How much filtrate must the nephron absorb?
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99%
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What is tubular secretion?
What does it help do? |
Transfer of materials from blood into tubular fluid
Helps control blood pH because of secretion of H+ and eliminate certain substances |
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What are 2 reabsorption routes? And explain them
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Paracelluar- movement between cells by diffusion, 50 % of reabsorbed material
Transcelluar- material moves through the apical and basal membranes by active transport |
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What is reabsorbed in the PCT? secreted?
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Reabsorbed- water, Na+, K+, glucose, amino acids, lactic acid, water souble vitamins, Cl-, HCO-, urea, Ca+2, Mg+2
Secrete- H+, ammonium ions, urea |
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What is reabsorbed in the loop of Henle? secreted?
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Reabsorbed- water, Na+, K+, Cl-, HCO3-, Ca2+, Mg2+
Secreted- Nothing, but K+ has a leakage pump |
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What hormone increases the reabsorption of Ca+ in early distal tubule cells?
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Parathyroid hormone
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What hormones affect Na+, Cl-, and water reabsorption and K+ secretion in the tubules?
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Angiotensin II
Aldosterone ANP |
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Angiotensin II
Stimuli? Mechanism and site of action? Effects? |
Low blood volume or BP
Stimulates activity of Na+/H+ antiporters in PTC Increases reabsorption of Na+, other soultes, and water which increases blood volume |
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Aldosterone
Stimuli? Mechanism and site of action? Effects? |
Increased angiotensin II level and increased level of plasma K+
Enhances acivity of sodium-potassium pumps in basolateral membrane and Na+ channels in apical membrane in collecting ducts Increases secretion of K+ and reabsorption of Na+, Cl-, increases reabsorption of water |
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Atrial natriuretic peptide
Stimuli? Mechanism and site of action? Effects? |
Stretching of atria of heart
Supresses reabsorption of Na+ and water in proximal tubule and collecting duct; inhibits secretion of aldostreone and ADH Increases excretion of Na+ in the urine; increases urine output and thus decreases blood volume |
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Antidiuretic hormone
Stimuli? Mechanism and site of action? Effects? |
Increased osmolarity of extracellular fluid or decreased blood volume
Stimulates insertion of water channel proteins into the apical membranes of the principal cells Increases facultative reabsorption of water, which decreases osmolarity of body fluids |
