URINE

What organ is responsible for filtering blood and forming urine?

Kidney

What are the components of the urinary system?

Kidneys, ureters, urinary bladder, and urethra

What are the primary functions of the kidney?

Filtration of blood, regulation of fluid and electrolytes, acid-base balance, and hormone secretion

What is the outermost covering of the kidney?

Renal fascia

What is the middle fatty layer that protects the kidney?

Perirenal fat

What is the innermost capsule directly surrounding the kidney?

Renal capsule

What structure is the outer region of the kidney?

Renal cortex

What structure is the inner region of the kidney?

Renal medulla

What are the cone-shaped structures in the medulla?

Renal pyramids

What separates the renal pyramids?

Renal columns

What is the tip of each renal pyramid called?

Renal papilla

What collects urine from the renal papilla?

Minor calyx

What forms when several minor calyces unite?

Major calyx

What structure is formed by the union of major calyces?

Renal pelvis

What structure connects the renal pelvis to the bladder?

Ureter

What is the structural and functional unit of the kidney?

Nephron

What are the two main parts of a nephron?

Renal corpuscle and renal tubule

What are the components of the renal corpuscle?

Glomerulus and Bowman’s capsule

What type of epithelium lines the parietal layer of Bowman’s capsule?

Simple squamous epithelium

What is the visceral layer of Bowman’s capsule made of?

Podocytes

What are the specialized cells that wrap around glomerular capillaries?

Podocytes

What are the filtration components of the glomerular filtration barrier?

Fenestrated endothelium, basement membrane, and podocyte filtration slits

What is the function of the glomerular filtration barrier?

Prevents blood cells and large proteins from passing into the filtrate

What are the supportive cells between glomerular capillaries?

Mesangial cells

What is the function of mesangial cells?

Phagocytosis, structural support, and regulation of glomerular filtration

What structure is responsible for regulating blood pressure and GFR?

Juxtaglomerular apparatus (JGA)

What are the three components of the JG apparatus?

Macula densa, juxtaglomerular cells, and extraglomerular mesangial cells

Where is the macula densa located?

In the distal convoluted tubule adjacent to the glomerulus

What do macula densa cells detect?

Sodium chloride concentration in the filtrate

What do juxtaglomerular (JG) cells secrete?

Renin

What stimulates the release of renin?

Low blood pressure or low NaCl detected by macula densa

What hormone is responsible for initiating the RAAS pathway?

Renin

What is the epithelium of the proximal convoluted tubule?

Simple cuboidal epithelium with brush border

What is the function of the proximal convoluted tubule?

Reabsorption of water, ions, and nutrients

What part of the nephron has a thin descending limb?

Loop of Henle

What is the epithelium of the thin descending limb?

Simple squamous epithelium

What is the epithelium of the thick ascending limb of the loop of Henle?

Simple cuboidal epithelium

What part of the nephron lacks a brush border and reabsorbs ions?

Distal convoluted tubule

What epithelium lines the distal convoluted tubule?

Simple cuboidal epithelium

What is the function of the distal convoluted tubule?

Selective reabsorption and secretion, pH regulation

What connects the nephron to the collecting ducts?

Connecting tubule

What is the function of the collecting duct?

Concentrates urine and responds to ADH

What epithelium lines the collecting duct?

Simple cuboidal to columnar epithelium depending on location

What structure carries urine from the renal pelvis to the bladder?

Ureter

What are the layers of the ureter wall?

Mucosa, muscularis, and adventitia

What is the epithelium lining the ureter?

Transitional epithelium (urothelium)

What is the function of the muscularis layer of the ureter?

Peristaltic propulsion of urine

What organ temporarily stores urine?

Urinary bladder

What epithelium lines the urinary bladder?

Transitional epithelium

What are the three layers of the bladder wall?

Mucosa, muscularis (detrusor muscle), adventitia/serosa

What is the function of the detrusor muscle?

Contracts to expel urine from the bladder

What epithelium lines the prostatic urethra in males?

Transitional epithelium

What epithelium lines the membranous urethra?

Pseudostratified columnar epithelium

What epithelium lines the penile urethra (spongy urethra)?

Pseudostratified or stratified columnar epithelium

What epithelium is found in the fossa navicularis of the penis?

Stratified squamous non-keratinized epithelium

What is the epithelium of the female urethra?

Stratified squamous epithelium

What part of the nephron is located in the renal cortex?

Renal corpuscle, proximal and distal convoluted tubules

What parts of the nephron extend into the medulla?

Loop of Henle and collecting ducts

What feature increases the surface area in the proximal tubule?

Brush border (microvilli)

What hormone increases water reabsorption in the collecting duct?

Antidiuretic hormone (ADH)

What hormone increases sodium reabsorption in the distal tubule?

Aldosterone

What is the purpose of transitional epithelium in the urinary tract?

Allows stretching and recoil of the urinary organs

What structure collects urine from multiple nephrons?

Collecting duct

What structure releases renin in response to low BP?

Juxtaglomerular cells

What is the function of renin?

Activates angiotensinogen to angiotensin I

What converts angiotensin I to angiotensin II?

Angiotensin-converting enzyme (ACE)

What is the function of angiotensin II?

Raises blood pressure by vasoconstriction and stimulating aldosterone

What is the purpose of the renal filtration barrier?

Permits filtration of plasma while retaining cells and large proteins

Where are podocytes located?

Visceral layer of Bowman’s capsule

What is the role of foot processes in podocytes?

Form filtration slits to regulate passage of substances

What are filtration slits bridged by?

Slit diaphragm

What kidney cells regulate glomerular filtration surface area?

Mesangial cells

What are extraglomerular mesangial cells part of?

Juxtaglomerular apparatus

What nephron structure is responsive to aldosterone?

Distal convoluted tubule

What structure is most responsive to ADH?

Collecting duct

What nephron segment is impermeable to water?

Thick ascending limb of Henle’s loop

What is the primary site for glucose and amino acid reabsorption?

Proximal convoluted tubule

What is the function of the thin descending limb?

Reabsorbs water

What is the function of the thick ascending limb?

Reabsorbs sodium, chloride, potassium but impermeable to water