Urinary System 1

• 2 Kidneys
• 2 Ureters
• 1 Urinary Bladder
• 1 Urethra

• -On either side of the vertebral column between L3 and T12.
• -Between the peritoneum and the back wall of the abdominal cavity.
• -The right kidney is lower than the left due to the liver.

• 1. Elimination of wastes
• 2. Conservation of nutrients
• 3. Regulates blood volume, composition, pH, and pressure
• 4. Synthesizes hormones

• 1. Urea
• 2. Uric acid
• 3. Ammonia
• 4. Bilirubin

• 1. Sodium (Na⁺)
• 2. Potassium (K⁺)
• 3. Calcium (Ca²⁺)
• 4. Phosphates (PO₄^3-)

By regulating ion concentration.

• 1. Calcitriol
• 2. Erythropoietin

It is the active form of vitamin D and it helps regulate calcium homeostasis.

It stimulates the production of red blood cells.

• An indentation near the center of the medial boarder of each kidney where:
• -Ureter leaves
• -Renal artery enters
• -Renal vein exits
• -Lymphatic vessels enter/exit
• -Nerves enter/exit

• 1. Renal Capsule--A smooth, transparent CT sheath that helps maintain the shape of the organ and acts as a barrier against trauma.
• 2. Adipose Capsule--Cushions the kidney.
• 3. Renal Fascia--A thin layer of dense irregular CT that anchors the kidney to the posterior abdominal wall.

• 1. Renal Cortex
• 2. Renal Medulla

• -cortex = rind, bark
• -The outer, light red region of internal kidney.

• -medulla = inner portion
• -Inner, darker red-brown region of internal kidney that contains several renal pyramids.

Extensions of the renal cortex that fill the spaces between renal pyramids.

Cone-shaped structures with wide bases adjacent to the renal cortex and a narrow apex called the renal papilla, where the papillary ducts pass to the minor calyx.

• -calyx = cup
• -Eight to eighteen cupcake structures that collect filtrate from renal ducts and empty into 2-3 major calyces.

• 1. Collecting duct
• 2. Papillary duct
• 3. Minor calyx
• 4. Major calyx
• 5. Renal pelvis
• 6. Ureters
• 7. Urinary bladder
• 8. Urethra

About 25% (~ 1200 ml)

About 4 minutes

• 1. Renal artery
• 2. Afferent arterioles
• 3. Glomerulus
• 4. Efferent arterioles
• 5. Peritubular capillaries
• 6. Renal veins

• -The multicellular functional units of the kidneys.
• -About 1.25 million/kidney

• 1. Renal Corpuscle
• 2. Renal Tubule

• -The site of blood filtration.
• -Composed of two parts--Glomerular Capsule & Glomerulus

-A convoluted capillary network surrounded by the glomerular capsule.

• -Also called the Bowman's capsule
• -A double-walled epithelial membrane cup that surrounds the glomerulus and the site of blood filtration.

• -Water and solutes are filtered out of blood
• -RBCs and plasma proteins are prevented from leaving blood (too large)

• -Tube where filtrate (i.e., filtered blood) passes after leaving the glomerular capsule.
• -Consists of 3 main portions

• -Proximal Convoluted Tubule
• -Nephron Loop
• -Distal Convoluted Tubule

• 1. Glomerular Filtration
• 2. Tubular Reabsorption
• 3. Tubular Secretion

• 1. Blood is delivered to the renal corpuscle via the renal artery.
• 2. Blood pressure builds in glomerulus, causing filtration to occur.
• 3. Blood cells and proteins remain in blood and water and solutes  (renal filtrate) pass into renal tubules.

• 1. Tubular cells reabsorb ~ 99% of the filtered water and many solutes.
• 2. Most reabsorption occurs in the proximal convoluted tubule.

Na⁺, Ca²⁺, K⁺, amino acids, glucose