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Chapter 24: The Urinary System - Coggle Diagram

- - - - External Anatomy of Kidneys
        
        Fibrous Capsule
        
        Capsule of dense connective tissue surrounds the kidney
        
        Inhibits spread of infections
        
        Helps maintain shape
        
        Perirenal Fat Capsule
        
        External to renal capsule
        
        Renal Fascia
        
        External to perirenal fat capsule
        
        Connect to posterior abdominal wall
        
        Inhibits spread of infections or tumor
        
        Hilium
        
        On the concave/medial surface
        
        Where vessels, ureters & nerves enter & exit
      - Internal Anatomy of Kidneys
        
        Renal Cortex
        
        Superficial region
        
        Granular appearance
        
        Renal Medulla
        
        Consists of:
        
        Cone-shaped renal pyramids
        
        Pyramid separated by renal columns
        
        Inward extensions of cortical tissue
        
        Papilla
        
        Tip of pyramid
        
        Releases urine into minor calyx
        
        Lobe
        
        A single renal pyramid + the cortical tissue that surrounds the pyramid
        
        5-11 lobes per kidney
        
        Renal Pelvis
        
        Funnel-shaped tube continuous with ureter
        
        Minor Calyces
        
        Drain pyramids at papillae
        
        Major Calyces
        
        Collect urine from minor calyces
        
        Empty urine into renal pelvis
        
        Gross Vasculature
        
        Renal arteries branch into segmental arteries
        
        Segmental arteries branch into interlobar arteries
        
        Arcuate arteries branch from interlobar arteries
      - Microscopic Anatomy of Kidneys
        
        Nephron is functional unit of kidney
        
        More than 1 million nephrons in each kidney
        
        Renal Tubule
        
        Filtrate proceeds to renal tubules from glomerulus
        
        Proximal Convoluted Tubule
        
        Nephron Loop
        Loop of Henley
        
        Descending limb
        
        Ascending limb
        
        Distal Convoluted Tubule
        
        Collecting Ducts
        
        Receive urine from several nephrons
        
        Play an important role in conserving body fluids
        
        Posterior pituitary secretes antidiuretic hormone (ADH)
        
        Antidiuretic Hormone (ADH)
        
        Increases permeability of collecting ducts & distal convoluted tubules to water
        
        ADH is secreted to retain water when dehydrated
        
        Water is pulled out of collecting ducts & back into body to be reabsorbed into the blood
        
        Renal Corpuscle
        
        1st part of nephron
        
        Glomerulus
        
        Tuft of capillaries
        
        Capillaries of glomerulus are fenestrated (have pores)
        
        Produce filtrate that becomes urine
        
        Fed & drained by arterioles
        
        Generate 1L of fluid every 7 min
        
        99% of filtrate is resorbed bye tubules
        
        Filtration Membrane
        
        Lies between blood in the glomerulus & capsular space
        
        Basement membrane & slit diaphragm
        
        Hold back all but the smallest proteins
        
        Allows passage of water, ions, glucose, amino acids, urea
        
        Filtration is driven bye pressure
        
        Arterioles
        
        Afferent Glomerular Arteriole
        
        Efferent Glomerular Arteriole
        
        Smaller diameter than afferent arteriole
        
        Glomerular (Bowman's) Capsule
        
        Parietal layer of simple squamous epithelium
        
        Visceral layer of podocytes
        
        Classes of Nephron
        
        Cortical Nephrons
        
        85% of nephrons
        
        Juxtamedullary Nephrons
        
        15% of nephrons
        
        Contribute to kidney's ability to concentrate urine
        
        The descending side is freely permeable to water
        
        Ascending side pumps salt out into medulla
        
        This pulls water out of descending limb & concentrates the urine
        
        Blood Vessels Associated with Nephrons
        
        Nephrons associate closely with 2 capillary beds
        
        Glomerulus
        
        Peritubular capillaries in cortical nephrons or vasa recta in juxtamedullary nephrons
        
        Peritubular Capillaries
        
        Arise from efferent arterioles draining cortical glomeruli
        
        Are adapted for absorption & secretion
        
        Low-pressure, porous capillaries
        
        All molecules secreted by nephrons into urine are from peritubular capillaries
        
        Vasa Recta
        
        Continue from efferent arterioles of juxtamedullary nephrons
        
        Are thin-walled looping vessels
        
        Descend into the medulla
        
        Are part of the kidney's urine concentrating mechanism
        
        Juxtaglomerular Complex
        
        Functions in regulating blood pressure
        
        An area of specialized contact between terminal end of the ascending limb & afferent arteriole
        
        Granular Cells
        
        Modified smooth muscle cells with secretory granules
        
        Contain hormone renin
        
        Renin is secreted in response to failing/low blood pressure in afferent arteriole
        
        Causes kidney to retain more salt, to attract more water, to increase blood volume
        
        Macula Densa
        
        End of nephron loop
        
        Adjacent to granular cells
        
        Tall, closely packed epithelial cells
        
        Monitor sodium concentration in the filtrate
        
        Signal granular cells to secrete renin
        
        Initiates renin-angiotensin mechanism
    - - Histology of Ureter
        
        Mucosa
        
        Transitional epithelium
        
        Muscularis
        
        2 layers
        
        Inner longitudinal layer
        
        Outer circular layer
        
        Adventitia
        
        Typical connective tissue
    - - Prostate
        
        In males:
        
        The prostate lies directly inferior to bladder
        
        Surrounds the urethra
      - 3 Layers
        
        Mucosa
        
        Transitional epithelium
        
        Detrusor
        
        Thick muscular layer
        
        Adventitia
        
        Typical connective tissue
      - Micturition
        Voiding or Urination
        
        Act of emptying bladder
        
        Controlled by the brain & involves both autonomic & somatic pathways
    - - Epithelium of urethra
        
        Transitional Epithelium
        
        At the proximal end (near bladder)
        
        Stratified & Pseudostratified Columnar
        
        Mid-urethra (in males)
        
        Stratified Squamous Epithelium
        
        At the distal end (near urethral opening)
      - Internal Urethral Sphincter
        
        Involuntary smooth muscle
      - External Urethral Sphincter
        
        Voluntarily inhibits urination
        
        Relaxes when one urinates
      - 3 Regions of Main Urethra
        
        Prostatic Urethra
        
        Passes through the prostate gland
        
        Intermediate Part of Urethra
        
        Membranous urethra
        
        Passes through urogenital diaphragm
        
        Spongy (Penile) Urethra
        
        Passes through the length of the penis