Please enable JavaScript.

Coggle requires JavaScript to display documents.

Digestive and Urinary System Yoselin Mora Period 3 - Coggle Diagram

- - - - Renal Corpuscle
        -2 parts:
        
        Glomerulus
        -tuft of capillaries composed of fenestrated endothelium
        -Highly porous capillaries
        -Allows for efficient filatrate formation
        -Filtrate: plasma-derived fluid that renal tubules process to form urine
        
        Glomerular Capsule
        -AKA Bowman's capsule: cup-shapedm hollow structure surrounding glomerulus
        -Consists of 2 layers
        -Parietal and visceral layer
        -Visceral layer clings to glomerular capillaries; branching epithelial podocytes
        -extensions terminate foot processes that cling to basement membrance
        -Filtration slits b/w foot processes allow filtrate to pass into Capsular space
      - Renal Tubule and Collecting Duct
        -Renal tubule is about 3 cm long
        -Consists of single layer of epithelial cells, but each region has its own unique histology and function
        -3 major parts
        
        Proximal convoluted tubule
        -Proximal, closest to renal corpuscle
        -functions in reabsorption and secretion
        -confined to cortex
        
        Nephron Loop
        -U-shaped structure consisting of 2 limbs
        -Descending limb: proximal part of descending limb is continuous w/ proximal tubule, distal portion also called descending thin limb
        -Ascending limb: thick ascending limb, thin in some nephrons, cuboidal or columnar cells
        
        Distal convoluted tubule
        -Distal farthest from renal corpuscle
        -Function more in secretion than reabsorption
        -Confined to cortex
        
        Collecting Ducts
        -2 cell types
        -principal cells
        -Spare w/ short Microvilli
        -Maintain water and sodium balance
        -Intercalated cells -Cuboidal cells w/ abdundant Microvilli
        -Two types of Intercalated cells
        -A and B both help maintain acid-base balance of blood
        -Collecting ducts receive filtrate from many nephrons
        -Run through medullary pyramids
        -Give pyramids their striped appearance
        -Ducts fuse together to deliver urine through papillae into minor calyces
      - Physiology of Kidney
        -180 L of fluid processed daily, only 1.5 L of urine formed
        -filter body's entire plasma volume 60x each day
        -Consume 20-25% of oxygen used by body at rest
        -Filtrate is basically blood plasma minus proteins
        -Urine is produced from filtrate
        Urine
        -Less than 1% of original filtrate
        -Contains metabolic wastes and unneeded substances
        
        Step 1: Glomerular Filtration
        -A passive process
        -No metabolic energy required
        -Hydrostatic pressure forces fluids and solutes through filtration membrane into glomerular capsule
        -No reabsorption into capillaries of glomerulus occurs
        Step 2: Tubular Reabsorption
        -Quickly reclaims most of tubular contents and returns them to blood
        -Selective transepithelial process
        -Almost all organic nutrients are reabsorbed
        -Water and ion reabsorption is hormonally regulated and adjusted
        -Includes active and passive tubular reabsorption
        Substances can follow 2 routes:
        
        Transcellular
        
        Paracellular
        
        Step 3: Tubular Secretion
        -Reabsorption in reverse
        -Occurs almost completely in PCT
        -Selected substances are moved from peritublar capillaries through tubule cells out into filtrate
        -Tubular Secretion is important for:
        -Disposing of substances, such as drugs or metabolites, that are bound to plasma proteins
        -Eliminating undesirable substances that were passively reabsorbed (ex: urea and uric acid)
        -Ridding body of excess K+ (aldosterone effect)
        -Controlling blood pH by altering amounts of H+ or HCO-3 in urine