Urinary Anatomy & Histology
Urinary Anatomy & Histology Detailed Study Notes
Models of the Urinary System
Outline of significant structures modeled:
Kidney
Right and Left kidneys distinguished.
Fibrous Capsule
Protective outer layer of the kidney.
Renal Pyramid
Cone-shaped tissues of the renal medulla.
Renal Pelvis
Central cavity that collects urine.
Minor Calyx
Collects urine from renal papillae; smaller cavities.
Major Calyx
Formed by the convergence of minor calyces; leads to renal pelvis.
Renal Papillae
Tips of the renal pyramids where urine drains.
Renal Column
Tissue between renal pyramids; composed of cortical tissue.
Renal Cortex
Outer region of the kidney containing renal corpuscles and tubules.
Renal Medulla
Inner region containing renal pyramids.
Renal Hilum
Entry and exit point for blood vessels, nerves, and ureter.
Renal Corpuscle
Structural and functional unit of the kidney.
Glomerulus
Network of capillaries within the renal corpuscle; site of filtration.
Efferent Arteriole
Carries blood away from the glomerulus.
Afferent Arteriole
Brings blood to the glomerulus.
Glomerular Capsule
Encloses the glomerulus; also known as Bowman’s capsule.
Bowman’s Space
Space between the glomerulus and the glomerular capsule where filtrate collects.
Podocytes
Specialized cells in the glomerulus that form filtration slits.
Juxtaglomerular Apparatus
Structure regulating blood pressure and glomerular filtration rate.
Macula Densa
Specialized cells in the distal convoluted tubule sensing sodium concentration.
Renal Tubule
Continues from glomerular capsule; includes various segments.
Proximal Convoluted Tubule
First segment of renal tubule involved in reabsorption.
Loop of Henle
Consists of descending and ascending limbs with thick and thin segments; plays crucial role in concentration of urine.
Distal Convoluted Tubule
Final segment of the renal tubule; involved in secretion and further reabsorption.
Collecting Duct
Receives urine from nephrons and helps in concentration.
Juxtamedullary Nephron
Nephron type with long loops of Henle; essential for urine concentration.
Cortical Nephron
Nephron type mostly located in the renal cortex.
Renal Artery and Vein
Supplies blood to the kidney and returns it to the body, respectively.
Segmental Artery
Branches of the renal artery; supply blood to the kidney.
Interlobar Artery and Vein
Transition between segmental and arcuate vessels; travel between renal columns.
Arcuate Artery and Vein
Arch over the bases of the pyramids.
Cortical Radiate Artery and Vein
Supply blood to the renal cortex; branches of the arcuate vessels.
Peritubular Capillaries
Surround nephron tubules; involved in reabsorption and secretion.
Vasa Recta
Capillary loops in the medulla; associated with juxtamedullary nephrons.
Ureters
Tubes carrying urine from kidneys to bladder.
Additional Structures
Further anatomical features:
Internal Urethral Sphincter
Muscular structure; controls urine release in both males and females.
Prostate Gland
Gland in males; produces seminal fluid and plays a role in urinary control.
Male Urethra
Divided into prostatic and spongy urethra sections.
Female Urethra
Single tube transporting urine from the bladder.
Bladder
Muscular sac for urine storage.
Detrusor Muscle
Smooth muscle layer of the bladder; contracts during urination.
Rugae
Folds in the bladder lining; allow for expansion.
Additional Images:
Structures to visualize:
External Urethral Sphincter (male and female).
Membranous Urethra.
Kidney Dissection
Key dissection points for anatomical understanding:
Renal Capsule
Renal Pyramid
Renal Pelvis
Minor Calyx
Major Calyx
Renal Papillae
Renal Column
Renal Cortex
Renal Medulla
Renal Hilum
Ureter
Functions of Urinary Structures
Detailed roles of key components:
Kidney
Filters blood, regulates fluid and electrolyte balance.
Nephron
Functional unit of the kidney; essential for filtration, reabsorption, and urine formation.
Glomerulus
Site of primary filtration of blood.
Glomerular Capsule
Collects filtrate from the glomerulus.
Proximal Convoluted Tubule
Reabsorbs nutrients, ions, and water from filtrate.
Podocytes
Regulate filtration through slits in the glomerular capsule.
Juxtaglomerular Apparatus
Detects blood pressure changes; regulates renal blood flow.
Loop of Henle
Concentrates urine; establishes medullary concentration gradient.
Distal Convoluted Tubule
Further modifies filtrate; important for acid-base balance.
Collecting Duct
Final concentration of urine occurs here before it exits the body.
Afferent Arteriole
Supplies blood to the glomerulus.
Efferent Arteriole
Drains blood from the glomerulus after filtration.
Peritubular Capillaries
Aid in reabsorption during urine formation.
Vasa Recta
Supply nutrients to the renal medulla and assist in counter-current exchange.
Renal Artery and Vein
Ensure supply and drainage of blood in and out of the kidney.
Ureter
Conducts urine to the bladder.
Bladder
Stores urine until expulsion.
Urethra
Conducts urine from bladder to the external environment.
Urine and Fluid Flow Summary
Pathway and mechanisms involved:
Blood flow through vessels: Glomerular filtration initiates urine formation.
Urine flow: From nephrons through collecting ducts into the renal pelvis, then to ureters.
Fluid flow through nephron: Involves filtration, reabsorption, and secretion processes.
Histology of the Kidney
Microscopic examination points:
4X Objective for Kidney: Identify the broad structures of cortex and medulla.
40X Objective for Kidney: Detailed examination of renal corpuscles, glomerulus, capsule, and Bowman’s space.
Histology of the Bladder
Microscopic examination points:
4X Objective for Bladder: General appearance of epithelium and detrusor muscle.
40X Objective for Bladder: Transitional epithelium, adaptive to stretching during bladder filling.