Urinary

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Urinary System
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I. Introduction to Urinary System

• The general function of the urinary system is to
  maintain homeostasis by balancing the volume and
  chemical make up of the blood (thus Kidney has
  long term control of blood pressure) and
  elimination of wastes toxins, nitrogenous
  wastes, and excess ions

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B. Parts

• 1. Kidneys
• 2. Ureters
• 3. Urinary
• Bladder
• 4. Urethra

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• Long paired muscular tubes that drain each kidney
  and propel urine by peristalsis into the urinary
  bladder.
• Stretchy storage unit for urine, contracts to
  empty
• Urine exits body thru urethra, a narrow tube
  about 1.5 inches in females and 8 inches in males

2. Ureters
3. Urinary Bladder
4. Urethra
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3. Urinary Bladder

• Collection and storage area for urine.
• Collapsed when empty.
• Longitudinal circular smooth muscle
• Transitional epithelial tissue
• Internal sphincter and external sphincter

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1. Kidneys
C. Structure of Parts

• Located in lower back T12-L3, just under 12th rib
• 7 lobes
• Three layers of supportive tissue (renal capsule,
  adipose capsule, fibrous capsule)
• Parts of K are cortex, medulla w/ Calyces
  (pyramids), renal pelvis, renal sinus and hilus

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5. Blood supply 1/4 of blood

• Need to know

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Blood supply
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6. Parts of nephron, functional unit of kidney
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a. 2 types of nephrons

• Juxtamedullary
• Cortical

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b. The glomerulus
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c.
Bowmans capsule,
Efferent Arteriole connects
to Peritular Capillaries

• Nephron

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• d. Filtration membrane in glomerulus
• Pressure within Glomerulus produces filtrate
  (ions, glucose, water, amino acids)

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(2) 2 highly permeable membranes due to
fenestrations, podacytes thin basement
membranes in glomerulus

• Layer 1 is gomerular fenestrations of glomerular
  capillaries
• Layer 2 is fusion of glomerlular renal capsule
  basement membranes
• Layer 3, the podacyte
• is visceral layer of renal capsule, has slit
  diaphragms (filter) between podacytes.
• Filtrate enters Bowmans capsular space

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• e. Cell types in nephron (how kidney works)
• (1) PCT cubodial epithelium w/ microvilli.
  Absorption from PCT to peritubular capill.
• (2) Loop of henle, thin segment is simple
  squamous for osmosis of H20 out and into blood
  water follows Na from left side loop.
• (3) Collecting ducts are cuboidal/columnar w/
  aquaporins inserted when ADH for urine
• (4) DCT lumen is ridged. M/B is enfolded, for
  secretion movement from blood to DCT(pH).
• (5) JG cells (JGA) BP sensors in arterioles,
  smooth muscle cells control diameter of As
• (6) Macula densa (JGA), chemoreceptors in DCT
  promote dilation or constriction of afferent
  Arteriole, as Renin is released eA is
  constricted, as are other BV of body rise in
  BP.

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• (7) Peritubular capillaries arise from efferent
  arteriole and surround PCT and other tubules, but
  are called vasa recta when long loops of henle
  dip down into medulla in juxtamedullary nephrons.
  (F) is removal of H2O which follows Na urine

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f. Histology of kidney
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• Tubules, PCT DCT (no microvilli)

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Shows collecting duct
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Cortex of Kidney
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Pyramids and Renal Pelvis
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• End of story the Liquid that remains in
  tubules , leading to Collecting ducts excess
  water and ions, waste toxins is sterile
• Whooda guessed?

Urine.