Urinary System

What are the major organs of the urinary system?

kidneys, ureters, urinary bladder, urethra

What is the function of the urinary system?

waste removal and fluid balance

What is the medial surface of the kidney characterized by?

A concave with a vertical cleft called the renal hilum.

What surrounds each kidney to prevent infections from spreading to the kidney?

A fibrous capsule surrounds each kidney.

What is located atop each kidney?

An adrenal (suprarenal) gland, which is an endocrine gland functionally unrelated to the kidney.

What is the most superficial region of the kidney?

Renal cortex

What is the darker, reddish-brown region deep to the renal cortex?

Renal medulla

What are the cone-shaped tissue masses in the renal medulla called?

Medullary, or renal, pyramids

Which way does the broad base of each pyramid face?

Toward the cortex

What do the renal columns separate in the kidney?

The pyramids

What is the tube continuous with the ureter leaving the hilum of the kidney?

Renal pelvis

What are the branching extensions of the renal pelvis called?

Major calyces

What encloses the papillae in the kidney?

Minor calyces

How does each renal artery divide as it approaches a kidney?

It divides into five segmental arteries.

What do interlobar arteries branch into?

Arcuate arteries.

What type of arteries radiate outward from the arcuate arteries to supply cortical tissue?

Small cortical radiate arteries.

What begins a complex arrangement of microscopic blood vessels in the kidney?

Afferent arterioles.

How do veins mostly trace the pathway in the kidney?

They trace the pathway of the arterial supply in reverse.

What are nephrons?

The structural and functional units of the kidneys.

What are the components of a nephron?

Each nephron consists of a renal corpuscle and a renal tubule.

What does a renal corpuscle consist of?

Consists of a tuft of capillaries called the glomerulus and a glomerular capsule (or Bowman’s capsule).

What is the endothelium of the glomerular capillaries like?

Is fenestrated (penetrated by many pores).

How is the glomerular capsule structured?

Has a parietal layer and a visceral layer.

What are the epithelial cells in the visceral layer of the glomerular capsule called?

Has epithelial cells called podocytes.

What are the three parts of the renal tubule?

Proximal convoluted tubule (PCT), Nephron loop, Distal convoluted tubule (DCT)

What is the function of the proximal convoluted tubule (PCT)?

Filtrate passes through here first, cuboidal epithelial cells with large mitochondria, apical surfaces bear dense microvilli

What is the structure of the distal convoluted tubule (DCT)?

Cuboidal cells confined to the cortex, thinner and almost entirely lack microvilli

What receives filtrate from many nephrons?

Collecting duct

What is the Juxtaglomerular Complex (JGC)?

Region in each nephron where the distal portion of the ascending limb of the nephron loop lies against the afferent arteriole feeding the glomerulus.

What is the role of Macula densa cells in the Juxtaglomerular Complex (JGC)?

Monitor the NaCl content of the filtrate entering the DCT.

What do Granular cells in the Juxtaglomerular Complex (JGC) sense?

Blood pressure in the afferent arteriole.

What is the percentage of cortical nephrons in the kidneys?

85%

How do cortical nephrons differ from juxtamedullary nephrons in terms of nephron loop length?

Cortical nephrons have short nephron loops, while juxtamedullary nephrons have long nephron loops.

Where is the glomerulus located in relation to the cortex-medulla junction in juxtamedullary nephrons?

The glomerulus is closer to the cortex-medulla junction in juxtamedullary nephrons.

What is the function of the ureter?

Convey urine from the kidneys to the bladder.

How many layers make up the structure of the ureter?

Three layers - mucosa, muscularis, adventitia.

What is the function of the bladder?

The bladder is a smooth, collapsible, muscular sac that stores urine temporarily.

What are the three layers of the bladder?

Mucosa, middle layer (detrusor), and fibrous adventitia.

What is the triangular region of the bladder base outlined by three openings for ureters and the urethra called?

The smooth, triangular region of the bladder base is called the trigone.

What is the urethra?

A thin-walled muscular tube that drains urine from the bladder and out of the body.

How is the internal urethral sphincter controlled?

Involuntary and controlled by the autonomic nervous system.

What controls the external urethral sphincter?

The external urethral sphincter is under voluntary control.

How do the length and functions of the urethra differ between males and females?

In females, the urethra is 3-4 cm long, with the external urethral orifice lying anterior to the vaginal opening and posterior to the clitoris. In males, the urethra is approximately 20 cm long, divided into 3 regions, and functions to carry semen as well as urine.

What is histology?

Histology is the study of the microscopic structure of tissues.

What does the top image in histology show?

The top image in histology shows the detailed structure of the nephron.

What does the lower image in histology show?

The lower image in histology shows a low-power view of the renal cortex.