Week 13 Content Flashcards
(141 cards)
The Urinary System
Role in maintaining homeostasis
Key organ: Kidneys
- Maintain the chemical consistency of blood
- Process blood, filters liters of fluid
Kidneys as Filters
Remove toxins, metabolic wastes, and excess water
Main waste products are nitrogenous waste products
1. Urea
2. Uric acid
3. Creatinine
Kidney Function
Acid-base balance
Water balance
Erythropoiesis
Toxin removal
Blood pressure
Electrolytes
D - Vitamin D metabolism
Mnemonic: A WET BED
Organs of the Urinary System
Upper Urinary Tract
- Kidneys
- Ureters
Lower Urinary Tract
- Urinary bladder
- Urethra
Kidney Position
Located retroperitoneally
Lateral to T12-L3 vertebrae
Average kidney is 12 cm tall, 6 cm wide, and 3 cm thick
External Anatomy of Kidneys
- Hilum
- Fibrous capsule
- Perirenal fat capsule
- Renal fascia
Hilum
Indented area on medial surface
Vessels enter and exit
Renal Artery: Oxygenated blood in
Renal Vein: Filtered blood out
Ureter: Transports urine to bladder
Nerves and Lymphatics: Support kidney function and drainage
Fibrous Capsule
Renal capsule
Tough, protective layer of connective tissue
Surrounds the kidney
Protects against damage and infection
Maintains kidney shape and structure
Perirenal Fat Capsule
Adipose tissue surrounds the kidney
External to fibrous capsule
Cushions and protects kidney
Provides insulation
Anchors kidney in place
Renal Fascia
Connective tissue surrounds kidneys
External to perirenal fat capsule
Anchors kidneys
Protects from movement and trauma
Separates from surrounding tissues
Kidney Diagram
Internal Gross Anatomy of the Kidneys
- Renal cortex
- Renal medulla
- Renal pelvis
- Renal arteries
- Nerve supply
Renal Cortex
Outer layer beneath capsule
Contains nephrons and blood vessels
- Granular appearance
Site of blood filtration and urine formation
Produces erythropoietin
Renal Medulla
Inner kidney beneath cortex
Has cone-shaped renal pyramids
Urine exits through renal papillae
Contains loops of Henle and collecting ducts for urine
Reabsorbs water and salts
Transports urine to renal pelvis
Renal Calyces
Minor Calyx: Collects urine from renal pyramids (renal papillae)
Major Calyx: Formed by merging minor calyces
- Funnel urine into renal pelvis
Renal Pelvis
Funnel-shaped cavity in center of kidney
Collects urine from calyces
Channels urine to ureter for elimination
Proximal Pathway of Urine Conduction
Kidney Diagram
Gross Vasculature
Renal artery carries oxygen-rich blood from aorta to kidney
Branches into segmental arteries
- Interlobar arteries between renal pyramids
- Arcuate arteries around base of renal pyramids
- Cortical radiate arteries: Supply renal cortex
Venous Drainage
Cortical radiate veins - Arcuate veins - Interlobar veins
Renal vein returns deoxygenated blood to the inferior vena cave
Supports filtration
Waste removal
Regulates blood pressure
Path of Blood Flow through Renal Blood Vessels
Nerve Supply of the Kidneys
Controls blood flow and urine production
Renal Plexus: Main nerve network, autonomic fibers
Branches from the celiac plexus
Sympathetic innervation from…
- Thoracic splanchnic nerve
- Lumbar splanchnic nerve
Mechanisms of Urine Production
Filtration: Blood filtered in kidney capillaries, forms filtrate
Resorption: Reclaims nutrients, water, and ions into blood
Secretion: Removal of unwanted molecules from blood into filtrate
Microscopic Anatomy of the Kidneys
Nephron is the functional unit of the kidney
- More than 1 million nephrons in each kidney