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Functions of urinary system
- Removes metabolic wastes from blood/ body
- Removes toxins from the body
- Maintains normal water balance, electrolyte balance, and pH of body (blood)
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Renal pelvis
Funnel shaped top of the ureter where urine collects
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Renal medulla
The inner portion that appears striated
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Renal cortex
Outer shell of the kidney that appears dense & solid
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Blood supply of renal arteries and renal veins
Renal arteries- carry 15-30% of cardiac output into kidneys from the abdominal aorta
Renal veins- Collect blood from the kidneys, draining into the inferior vena cava
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Nephron functions
- Filters blood
- Regulate blood volume & solutes
- Regulates pH
- Removes toxic wastes from the blood to form urine
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Renal corpuscle
filters the blood
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Glomerulus
Capillary tangle where fluids are forced out of the blood
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Bowman's (glomerular) capsule
Kidney tube that gathers filtered fluids from the blood
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Renal tubule
Carries fluids away from the renal corpuscle
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Collecting ducts
Formed from distal convoluted tubules from several nephrons
Merge to eventually drain into the minor calyx, to major calyx, to renal pelvis
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2 types of nephrons
Cortical nephrons- 85% of nephrons (function is blood filtration)
Juxtamedullary nephrons- Contain vasa recta surrounding a much longer loop of Henle (function to concentrate urine)
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Renin
enzyme secreted by juxtaglomerular apparatus, secreted into the blood
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Angiotensinogen
produced in liver, secreted into blood
- Cleaved by renin to form angiotensin I
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Angiotensin I
Still an inactive molecule in blood
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ACE
Angiotensin converting enzyme
- - Produced in lungs, secreted into blood
- - Converts angiotensin I into angiotensin II
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Angiotensin II
Multiple functions
- -a vasoconstrictor
- - stimulates the release of aldosterone & ADH
- - Causes hypothalamus to induce thirst
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Aldosterone
Produced by the adrenal cortex
- - Incr. tubular reabsorption of Na+ and Cl-
- - Incr. tubular secretion of K+
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ADH
Antidiuretic hormone
- - Produced by pituitary gland
- - Incr. reabsorption H2O from collecting duct
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Average urine % and pH
95% water and 5% solutes
pH 4.6-8.0 // Ave=6.0
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Urea
Waste product from deamination of amino acids
50% reabsorbed, 50% excreted
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Kidney metabolic function
Vitamin D production
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Ureters
Tube from the renal pelvis to the urinary bladder
Urine moves due to peristalsis, pressure & gravity
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Urethra
Tube carrying urine from the bladder out of the body
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Chronic Kidney Disease
Kidney damage leading to insufficient filtration
Wastes build up in the blood/ body
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Two types of Dialysis therapy
Hemodialysis and Peritoneal dialysis
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Hemodialysis
Removes waste and excess fluid from the blood when kidneys cant do so
Blood is drawn and sent through a machine and returned through a blood vessel
Usually performed 3 or more times a week for 4 hours or more
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Peritoneal dialysis
Cleans the blood without it being removed
Dialysate is injected into peritoneal space in the abdomen through a two-way catheter
The membrane that lines the abdomen allows waste and fluid to pass from the blood into the dialysate which is then pumped out
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Hemodialysis vs Peritoneal
Hem: Cleans better, short time treatment, must be in facility 3x/week, risk of hemorrhage, damages WBC
Per: Less effective cleaning, more hours hooked up, home treatment, risk of infection & peritonitis, easy on RBCs
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Human toxicology
Chemicals received in the body that aren't carbs, lipids, proteins, vitamins, minerals, water
The liver is the primary detox organ pathway
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Important factors in assessing human toxins
- Dosage
- Route of entry (Ingestion, inhalation, absorption)
- Excretability
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