Urinary/Renal System

Question 1

What organs does the renal system include? (4)

Answer 1

Kidneys, ureters, bladder, urethra

Question 2

What is the purpose of the urinary system? (4)

Answer 2

• Eliminate waste from the body
• Regulate blood volume/pressure
• Control levels of electrolytes/metabolites
• Regulate blood pH

Question 3

What are the kidneys?

Answer 3

Two bean-shaped retroperitoneal organs in the superior dorsal abdominal cavity (partly protected by lower ribs)
Filters blood and makes urine

Question 4

What is the ureter?

Answer 4

Tube that carries urine from each kidney to urinary bladder
Located in the inferior ventral pelvic cavity

Question 5

What is the urinary bladder?

Answer 5

An expandable sac holding urine

Question 6

What is the urethra?

Answer 6

Tube that transports urine from bladder to outside of body

Question 7

What is the renal hilum?

Answer 7

Indented area of the kidney

Question 8

What is the renal hilum an entrance for? (5)

Answer 8

Renal artery and vein, ureter, nerves, lymphatics

Question 9

What are the functions of the kidney? (7)

Answer 9

(A WET BED)
Control Acid-base balance
Control Water balance
Maintain Electrolyte balance
Remove Toxins and waste from body
Control Blood pressure
Produce Erythropoietin
Activate vitamin D

Question 10

What is the purpose of erythropoietin (EPO)? (2)

Answer 10

A hormone that acts on RBCs to protect against destruction
Stimulates stem cells to increase RBC production

Question 11

What produces EPO hormone?

Answer 11

Produced by specialized cells called interstitial cells in the kidney

Question 12

What is the renal cortex?

Answer 12

Outer layer of kidney

Question 13

What is the renal medulla?

Answer 13

Inner region of kidney

Question 14

What are the renal pyramids?

Answer 14

Secreting apparatus and tubules

Question 15

Where are the renal nephrons?

Answer 15

Mostly in the kidney cortex
Has short/thin segments in loop of Henle

Question 16

What is the renal pelvis?

Answer 16

Receives urine from collecting tubes of nephrons

Question 17

What are the layers of renal connective tissue? (3)

Answer 17

Renal fascia - anchors to other structures (most outer)
Adipose capsule - protects/anchors (middle)
Renal capsule - continuous with ureter (inner)

Question 18

What are nephrons?

Answer 18

Minute/microscopic structural/functional unit of the kidney
About 1m of these filtering units per kidney

Question 19

What are the two kinds of nephrons? - mostly based on location of glomerulus

Answer 19

• Cortical: about 85% of nephrons and loop of Henle is shorter in medulla
• Juxtamedullary: about 15% and loop of Henle is loner in the medulla

Question 20

What is the glomerulus?

Answer 20

Mass of fenestrated capillaries fed by the afferent arteriole and drains into efferent arteriole

Question 21

What do the glomerulus capillaries consist of? (3)

Answer 21

• Glomerular endothelial cells line it
• Basement membrane (barrier) lies below endothelium (external/internal lamina)
• Epithelium attaches to Podocytes of the visceral epithelium of Bowman capsule

Question 22

What is the glomerular (Bowman’s) capsule?

Answer 22

Where filtrate is collected within its lumen

Question 23

What are the layers of the Bowman’s capsule?

Answer 23

Parietal
Visceral (covered by Podocytes)

Question 24

What are podocytes and nephrin of the Bowman’s capsule?

Answer 24

Podocytes: feet-like projections that increase surface area for filtration
Nephrin: proteins linking podocytes together and allows small molecules to pass

Question 25

What is the movement of filtration of the glomerulus? (4)

Answer 25

Capillaries endothelial cells
Basement membrane
Podocytes
Lumen of Bowman capsule

Question 26

What are the five basic elements of the juxtaglomerular apparatus?

Answer 26

Terminal portion of afferent arteriole
Juxtaglomerular JC cells within afferent arteriole
Macular densa
Mesangial cells
Efferent arteriole at glomerulus

Question 27

What are the juxtaglomerular JC cells within the afferent arteriole? (2)

Answer 27

• Smooth muscle cells: arteriole constriction
• Granular cells: sense arteriole BP, synthesize/store/secrete enzyme renin

Question 28

What is the macula densa?

Answer 28

Segment of corner of ascending loop of Henle and distal tubule
Detects Na/K concentration of fluid in tubule to activate renin release

Question 29

What are the mesangial cells of the juxtaglomerular apparatus? (2)

Answer 29

• Intraglomerular cells: support cells to glomerulus, produces phagocytes to remove trapped residues/debris
• Extraglomerular cells: not well known

Question 30

What are the functions of the nephron? (5)

Answer 30

• Regulates extracellular fluid/osmolarity, electrolyte concentration, acid-base balance
• Excretes waste
  Secretes renin
• Produces erythropoietin
• Converts vit. D to active form

Question 31

Where does filtration of the nephron occur?

Answer 31

Glomerulus

Question 32

Where does reabsorption of the nephron occur?

Answer 32

Tubules

Question 33

Where does secretion of the nephron occur?

Answer 33

Tubules

Question 34

Where does excretion of the nephron occur?

Answer 34

Collecting duct

Question 35

What are the two major parts of a nephron?

Answer 35

• Glomerular (Bowman’s) capsule
• Long renal tubule (connects to common collecting duct)

Question 36

What are the three steps of the formation of urine?

Answer 36

• Glomerular filtration
• Tubular reabsorption & secretion
• Water conservation

Question 37

Which is larger: the afferent or efferent arteriole?

Answer 37

The afferent arteriole (large inlet, small outlet)
Blood hydrostatic pressure is high as a result
This pressure and osmotic pressure drive water and solutes from blood plasma through a filtration membrane (like a sieve) into nephron space

Question 38

Where are the points of reabsorption in the nephron tubules?

Answer 38

• Proximal convoluted tubule
• Loop of Henle (little water reabsorption, Na/K/Cl symporters)
• Early distal convoluted tubules (Na/Cl absorbed, parathyroid hormone stimulates Ca reabsorption and inhibits phosphate reabsorption)
• Late distal convoluted tubule & collecting duct