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Chapter 15
Urinary System
Kidney Anatomy
-Hillus
-Renal cortex
-Renal Medulla
-Medullary pyramids
-Renal Columns
-Renal Pelvis
-Calyces
Blood Supply and Path
-Enters kidney via Renal Artery, branches into smaller vessels:
-Glomerulus is sight of filtration, blood leaves glomerulus and head towards
venous system.
Anatomy of a Nephron
-A Nephron consists of:
-Glomerulus
-Proximal convoluted tubule
-Loop of Henle
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-Distal convoluted tubule
-Collecting ducts
-Glomerulus capillaries and peritubular capillaries
-juxtaglomerular apparatus
Urine Formation
-Urine Formation is the result of three processes, filtration, reabsorption, and
secretion.
-Filtration-
-Reabsorption-
-Secretion-
Characteristics of Urine
-Yellow color is due to broken down remains of hemoglobin
-Urine is sterile and slightly aromatic when formed
-Slightly acidic (pH 6) *changes in diet can change pH*
-Slightly higher specific gravity than water
-Changes in urine characteristics can be diagnostic of certain conditions
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Ureters-
Urinary Bladder-TrigoneUrethra-
Micturation-
Fluid, Electrolyte, Acid-Base Balance
4 roles in maintaining blood composition
1. excretion of nitrogenous wastes
2. maintaining water balance
3. maintaining water balance
4. ensuring proper blood pH
Water and Electrolyte Balance
-Fluid is contained in two compartments
1. Intracellular fluid volume2. Extracellular fluid-Electrolyte-kidneys regulate water and electrolyte concentrations
-Reabsorption of water and electrolytes by the kidneys are regulated primarily by
hormones.
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Acid-Base Balance
-Blood must be between 7.35 and 7.45 pH
-Acids and bases are released by cellular metabolism
-Kidneys, blood buffers, and respiratory system all work to maintain acid/base
balance.
Blood Buffers
-involves bicarbonate, phosphate, and protein buffers
HCl + NaHCO3  H2CO3 + NaCl
NaOH + H2CO3  NaHCO3 + H2O
Respiratory Buffers
-Uses gas exchange at the lungs to release CO2
CO2 + H2O  H2CO3  H+ + HCO3
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Renal Mechanisms
-In acidic conditions:
-In basic conditions:
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