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The urinary system consists of what?
- 2 kidneys
- 2 ureters
- the urinary bladder
- the urethra
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Where are the kidneys located?
Retroperitoneal (behind the peritoneum) on either side of the backbone
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What helps to hold them in place and cushion the kidneys?
- adipose tissue
- renal fascia
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The function of the kidneys?
- form urine
- to excrete waste products
- regulate the volume, electrolytes and pH of the blood and tissue fluid
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Outer tissue layer of the kidney, made of renal corpuscles and convoluted tubules
Renal cortex
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inner tissue layer of the kidneys, made of loop of henle, and collecting tubules and the pyramids
renal medulla
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a cavity formed by the expanded end of the ureter within the kidney at the hilus, extensions around the papillae of the pyramids are called calyx which collect urine
renal pelvis
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The structural and functional init of the kidney,
about 1 million in each kidney
Nephron
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consists of the glomerulus surrounded by the bowmans capsule
renal corpuscle
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Capillary network between an afferent and efferent arteriole
glomerulus
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the expanded end of the renal tubule that encloses the glomerulus
the inner layer is made of podocytes (has pores) and is very permeable
contains renal filtrate
Bowmans Capsule
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Consists of the proximal and distal tubules loop of henle and collecting tubes
Renal tubule
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Peritubular capillaries
arise from the efferent arteriole and surround all parts of of the renal tubule
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Blood vessel pathaway in the kidney
Abdominal aorta - renal artery - afferent - glomerulus - efferent - peritubular capillaries - renal vein - inferior vena cava
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Formation of urine
- 1 Glomerulus filtration
- 2 Tubular reabsorption
- 3 Tubular secretion
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Takes place in the glomerulus, high blood pressure in the glomerulus forces plasma, dissolved materials, small proteins out of the blood into the bowmans capsule == filtrate
Glomerular filtration
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Filtration is selectively permeable in terms of ___ ?
what remains in the blood ?
Size
Blood cells and large proteins
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Glomerular Filtration Rate
- amount of renal filtrate formed by the kidneys in 1 minute
- 100 - 125 mL per minute
- increased blood increases GFR
- decreased blood decreases GFR
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takes place from the filtrate in the renal tubules to the peritubular capillaries
99% of filtrate is reabsorbed only 1% becomes urine
tubular reabsorption
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reabsorption of glucose, amino acids, vitamins, and positive ions
Active transport
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Threshold level
a limit to how much can be absorbed
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transport of most negative ions, they follow the reabsorption of positive ions
passive transport
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transport of water
follows the reabsorption of sodium
osmosis
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small proteins are engulfed by proximal tubule cells
pinocytosis
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Aldosterone
- Secreted from the adrenal cortex
- increases the reabsorption of NA and K
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ADH - Anti diuretic horomone
- Secreted by the pituitary gland
- increases the absorption of H20 into the blood
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PTH - parathyroid horomone
- secreted by the parathyroid glands
- increases the absorption of Calcium and
- excretion of phosphate
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ANP - Atrial Natriuetic Peptide
- Secreted by the atria of the heart
- decrease the absorption of Sodium
- more sodium and water are excreted in the urine
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What do the kidneys excrete if the body fluids are becoming to acidic?
- Hydrogen Ions
- and return Bicarbonate ions to the blood
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What do the kidneys secrete if the body tissues are becoming to alkaline?
Bicarbonate ions and return more hydrogen ions to the blood
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When the blood pressure becomes to low, these cells secrete what to increase it?
Juxtaglomerular cells JG cells secrete renin
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What hormone causes vasoconstriction and increases the secretion of aldosterone?
Angiotensin 2
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What do the kidneys secrete in response to hypoxia? This hormone stimulates ____ to increase the production of ____?
- Erythropoeitin
- stimulates red bone marrow to produce RBCs
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A reservoir for urine?
Urinary bladder
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bladder is located where in females? and males
- females: below the uterus
- males: above the prostate
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Smooth muscle layer, a spherical muscle that contracts to expel urine?
Detrusor muscle
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how long is the urethra in males? females?
Males: 7-8 in long, passes through prostate and penis; also secretes semen
female: 1- 1.5 in long, anterior to the vagina
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involuntary sphincter that is formed by the detrusor muscle fibers around the opening of the urethra
Internal urethral sphincter
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Voluntary; skeletal muscle of the pelvic floor -- sphincter?
External urethral sphincter
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Stimulus of the urinary reflex?
stretching of the detrusor muscle by accumulating urine in the bladder
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Micturation
the urinary reflex
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the measurement of dissolved material in urine
specific gravity
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Characteristics of urine:
Amount, color, specific gravity, pH, composition, and nitrogenous wastes
- Amount = 1 - 2 L
- Color = straw or amber
- Specific gravity= 1.010 - 1.025
- pH = 6, range 4.6 - 8
- Composition = 95% water, 5% waste
- Nitrogenous wastes: Urea, creatinine, uric acid
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Urea
comes from amino acid metabolism
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Creatinine
comes from muscle metabolism
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Uric Acid
Comes from nucleic acid metabolism
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Glycosuria
glucose in the urine
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Proteinuria
Protein in the urine
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Hematuria
Blood in the urine
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Bacteriuria
Bacteria in the urine
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Ketonuria
Ketones in the urine
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Cystitis
inflammation of the bladder
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nephritis
inflammation of the kidneys
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