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55 Cards in this Set
- Front
- Back
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Kidney
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- 5 x 2 inches
- Below liver & behind all other organs - Vessels enter thru hilium (renal artery/vein, nerves, lymphatic vessels) |
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Functions of Kidney
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- Filters blood
(creates ultrafiltrate) - Waste elimination - Electrolyte balance - Acid-base balance (maintain pH) - Fluid regulation - Blood pressure regulation (RAA System) |
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Ureter (Function)
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Move ultrafiltrate to urinary bladder
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Urinary Bladder (Function)
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Store urine until excretion
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Urethra
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Connects bladder to outside
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Kidney (Anatomy)
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-Capsule
- Cortex (renal columns) - Medulla (renal pyramids) - Papilla - Calyx (major, minor) - Renal pelvis |
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Renal Capsule
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Outer layer of kidney (provides protection)
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Cortex
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- Under capsule
- Renal columns (extensions of the cortex that divide medulla into 6 - 10 pyramids) |
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Medulla
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Renal Pyramids (collections of microscopic units of kidney)
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Papilla
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"Small" end of pyramid (deep within pyramid)
Nephron loops extend into papillae |
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Minor Calyces
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- Cup which papillae in nestled
- Collects urine from papillae |
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Major Calyces
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Consists of 2 - 3 calyces
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Renal Pelvis
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Central cavity made of up 2 - 3 converged major calyces
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Blood Vessels of the Kidney
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- Renal artery
- Interlobar arteries - Arcuate arteries - Interlobular arteries - Afferent arterioles - Glomerulus - Efferent arteriole - Peritubular capillaries - Vasa recta |
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Renal Artery
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- Arises from aorta
- Enters thru Hilum - Divides into interlobar arteries |
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Interlobar Arteries
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- Travel along corticomedullary junction (boundary between cortex & medulla, penetrate renal columns)
- Branch into arcuate |
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Arcuate Arteries
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- Travel along base of pyramid
- Make sharp 90 degree angles |
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Interlobular Arteries
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Travel upward into cortex
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Afferent Arterioles
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- Arise from interlobular arteries
- Supply 1 nephron |
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Glomerulus
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- Ball of capillaries
- Enclosed in nephron structure called Bowman's capsule |
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Efferent Arterioles
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- Blood leaves glomerulus
- Leads to...paritubular capillaries & vasa recta |
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Paritubular Capillaries
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- Form a network around the renal tubules
- Pick up water & solutes reabsorbed by renal tubules |
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Vasa Recta
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Capillaries around nephrons deep within medulla
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Nephron
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- Functional unit of the kidney (1,000,000 per kidney)
- 2 Types (cortical, juxtaglomular) |
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Cortical
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- Short nephron loops
- Remain mostly in cortex |
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Juxtaglomular
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- Long nephron loops
- Protrude into the apex of the renal pyramid |
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Bowman's Capsule
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- Wraps around capillaries on glomerulus
- Called glomular filtrate (plasma without protein) |
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Nephron (Anatomy)
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3 Sections of renal tubules...
- Proximal convoluted tubule (PCT) - Loop of Henle - Distal convoluted tubule (DCT) |
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Proximal Convoluted Tubule (PCT)
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- Longest & most coiled tubule
- Responsible for reabsorption - Removes some substances from blood & secretes into tubule |
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Loop of Henle
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- Descending/ascending limb
- Thick: loops involved in active transport of salts - Thin: loops very permeable to water |
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Distal Convoluted Tubule (DCT)
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- Located in cortex near glomerulus
- Regulates blood pressure - End of nephron |
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Collecting Duct
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- Many DCT drain into one collecting duct
- In papilla, many collecting ducts drain into papillary duct - 30 papillary ducts from each papilla drain into minor calyx |
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Nephron (Functions)
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- Filtration
- Reabsorption - Secretion |
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Filtration
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- Occurs in Bowman's capsule
- Filters out small particles but not large proteins - Glomular pressure (hydrostatic pressure in capilarries) - Glomular filtration rate (GFR) 125mL/min of plasma >99% reabsorbed Kidney filters 1.2L/min (25% cardiac output goes to kidney) |
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Reaborption
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65 - 75% occurs in PCT
Reabsorbed 3 Ways... - Actively (uses ATP to pump ions, against gradients) - Passively (down a concentration gradient) - Osmotically (water diffuses across a membrane Osmotically) |
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Loop of Henle (Reabsoprtion)
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Descending Loop
- Permeable to water not salt - Fluid flows down descending, water diffuses into extra-cellular fluid osmotically Ascending - Impermeable to water (can't flow back in) - Actively transports salts into ECF to keep osmolarity high (salty) |
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Secretion
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- Tubular secretion occurs FROM capilarries INTO the nephron
- Peritubular capillaries into Proximal/Distal convoluted tubules... actively, passively, osmotically |
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Purposes of Secretion
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- Waste removal (natural & pollutants)
- Acid-base balance |
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Kidneys (Regulation)
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- pH
- Water conservation - Osmoregulation - Countercurrent multiplier |
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pH Regulation
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Blood: 7.4
Urine: 4.5 (acidic) to 9 (basic) - Renal system excretes H+ to maintain pH - Acidosis: excess H+ - Alkalotic: deficiency of H+ |
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Water Conservation
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Antidiuretic hormone (ADH)
- hormone synthesized by hypothalamus, & secreted via posterior pituitary gland - Many affects on the urine output of an individual |
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ADH Affects on Water Conservation
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- Draws water out tubules (DCT) back into blood
- Causes collecting ducts to be permeable to water (not normally) - Water gets drawn out of tubules when ADH is present High ADH = low urine volume Low volume of urine = very concentrated |
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How does the body know when it needs ADH?
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- Volume receptors
(Great vessels can sense plasma volume) - Osmoregulators (Hypothalamus senses osmolarity of blood) |
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Countercurrent Multiplier
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- Medulla has high salt concentration
(water diffuses out of descending loop into blood) - Medulla is kept at a high osmolarity by mechanism called countercurrent multipler (nephron loop continuously recaptures salt & returns it to medulla) |
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Countercurrent Exchange
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- Blood flows in opposite direction
- As blood flows into medulla, water flows of out capillaries, salt flows in - As blood flows back toward cortex, it exchanges salt for water (gives salt back) - Absorbs more water on the way out than gives on the way in (conserves water) |
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Urea Recycling
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- Occurs in collecting duct
- Urea accounts for 40% of the osmolarity in medulla - Lower end somewhat permeable to urea (diffuses out of the duct) - Some of the urea enters the descending loop (ascending nor DCT are permeable to urea) |
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RAA System
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Renin/Angiotensin/Aldosterone
- Renin released from kidney upon sympathetic NS stimulation or hypotension - Renin activates... Angiotensinogen, Angiotensin I, Angiotensin II |
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Angiotensin II
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- Widespread vasoconstriction
- Stimulates salt and water reabsorption - Stimulates adrenal cortex to secrete aldosterone (promoting sodium & water retention |
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Aldosterone
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- Salt retaining hormone
- Water follows sodium osmotically so salt retention = water retention - This promotes higher blood volume & pressure |
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Urinalysis Production & Normal Output
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1 - 2L of urine/day
Polyuria: excess of 2 L/day Oliguira: output of <500ml/day Anuria: output of 0 - 100ml/day |
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Urine
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- Specific gravity (1.001-1.028)
Low values = kidney disease High values = dehydration or diabetes mellitus Osmolarity: 500 - 800 mOsm/kg |
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Composition of Urine (Chemical Properties)
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pH: 4-5.8
- low = starvation, dehydration - high = UTI Chloride - High = high salt intake, diuretic - Low = low salt intake, PMS, diarrhea Urea/Nitrogen - High = excess protein intake - Low = not enough protein |
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cont...
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Protein
- High = hypertension Keytones - By product of fat metabolism - May be present during fasting, pregnancy, low carb diet Glucose - Should NOT be in urine (diabetes, trauma, surgery) |
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cont...
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Calcium
- Hypercalciuria: excess in urine Blood - May indicate kidney affection or stones Nitrate - Indicates bacterial infection of urinary tract Leukocytes - normal in small amounts, high amounts = UTI |
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Diabetes
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- Any metabolic disorder resulting in chronic polyuria
- Diabetes insipidus (results from ADH hyposecretion): no ADH = not enough water reabsorption |
