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Home , Peritubular capillaries, Podocyte, Proximal tubule

The

Objectives Function Evolution (Smith, role of the jaw) Anatomy structure Composition of Identification of components Excretory components One objective is to be able to identify these cells

Urinary System - Function in

Rid body of waste (, uric acid, creatinine,salts) Preserves constancy of extracellular fluid in composition, volume, and pH Endocrine function a) Secrete - red production b) Produces renin - aldosterone release Role of the jaw

Fresh

Salt water

PORTAL ARTERIOLE

Arterial Portal System Function of

Capillary  Portal portal system? Arteriole  = 1st afferent arteriole Local change , and PERITUBULAR in blood composition where first 2nd capillary modifies blood and second allows the 1st 2nd change in composition to affect local cells near it.

hilum hilum

Efferent Arteriole, Afferent Arteriole, and

Kidney Function Based on Combination of:

• Filtration • Active Secretion • Passive Diffusion • Selective Absorption http://www.youtube.com/watch?v=glu0dz

Glomerular Features for Extreme Filtration Very Large Surface Area (1.5 m2)

Large resistance afforded by reduced diameter of the efferent arteriole

Thin Filter (0.1 µm)

Thus, 25 times more permeable than regular capillaries Cells of the

Parietal Mesangial cell Endothelial cell Cells of the Glomerulus and Capsule

Parietal epithelium Podocyte Mesangial cell Endothelial cell Parietal Epithelium Podocyte

Mesangial Cell Endothelial Cell

Mesangial cells secrete erythropoietin - red blood cell production

Filtrate

Blood ?

Blood

Filtrate

Filtrate

Blood

Glomerulus - Passive

Endothelial cell >600,000 MW

Basal lamina >160,000 MW

Filtration slits >70,000 MW

Proximal Convoluted

Brush border

Acidophilic cytoplasm

Nuclei far apart

Indistinct lateral cell boundaries

fenestrated capillary

Distal Convoluted Tubules

No brush border Less acidophilic cytoplasm Nuclei relatively close Larger

Juxtaglomerular apparatus

Juxtaglomerular apparatus

258 Renin granules in JG cells of Kidney (PAS)

Angiotensinogen (Plasma Globulin)

Renin (Enzyme from JG Cells)

Angiotensin I

(Plasma Enzyme)

Angiotensin II (Most Potent Vasoconstrictor) Increased Blood Pressure

Angiotensin II

Vasoconstriction Aldosterone release from Adrenals

Increased Blood Pressure

Increased Sodium (Water by Distal )

Increased Blood Volume Adrenal Function Aldosterone stimulates Na+ resorption in:

• Distal tubule of kidney • Gastric mucosa • Salivary glands • Sweat glands

peritubular fenestrated endothelium

Cortical nephrons

Loop increases temperature over straight tube with same amount of heat

Juxtamedullay nephrons

Arterial Portal System

Capillary  Portal Arteriole  Capillary =

Afferent arteriole, Efferent Arteriole, and Peritubular Capillaries

Peritubular Capillaries

Absorbs - 180 liters/day from interstitial spaces; thus, ~4 Peritubular Capillaries times reabsorption of venous end of all other capillaries of body Endothelial cells - extremely porous Colloidal osmotic pressure of plasma Low capillary pressure Proximity to uriniferous tubules

Parathyroid Glands

Parathyroid hormone (PTH) acts on (osteocytes / osteoclasts), kidneys (increase reabsorption of distal tubules), and intestines (increase calcium absorption) to maintain tight control of calcium concentrations in the extracellular fluid ( 8.5 – 10.5 mg/100 mL) Calcium necessary for muscle contractions, glandular secretions, blood coagulation, and key enzymes of intermediary metabolism Removal of gland results in violent spasm of skeletal muscle (tetany) and ultimately death

Flow rate

Minor and major calyces are lined with transitional epithelium

Epithelia of the Urinary System

Simple Squamous Parietal, Thin Segment Simple Cuboidal Proximal, Distal Tubule Simple Columnar , Collection Ducts

Pseudostratified Columnar Stratified Squamous Urethra Stratified Columnar Urethra

Transitional Kidney, , Bladder, Urethra

Membranes

Cortical nephrons

Juxtamedullay nephrons