9. Urinary System

Question 1

Purpose of the urinary system

Answer 1

• Removal of waste products
• Assist liver to detoxify poisons
• Regulating blood volume and pressure
• Regulating plasma concentration of Na+, K+ & Cl-
• Helping to stabilize blood pH
• Conservation of valuable nutrients

Question 2

Osmolarity

Answer 2

Number of particles in specific volume of solution

Question 3

Gravity

Answer 3

Plasma and bodily fluids in urine. Normal: 290-300 mOsm/L

Question 4

Where are kidneys located?

Answer 4

Either side of the vertebral column, located in the abdominal cavity (retroperitoneal space).
Left kidney is superior to the right because of the liver.

Question 5

The Ureters

Answer 5

• Approx 30 cm long
• Has smooth muscles for peristalsis
• Liner with transitional epithelium

Question 6

The Urinary Bladder

Answer 6

Has folds for expansion: rugae
Has stretch receptors for micturition
Is muscular: smooth muscle = dertruser muscle

Question 7

Layers of the Urinary Bladder

Answer 7

Transitional epithelium
Laminate propria
Submucosa

Question 8

Transitional epithelium of the urethra

Answer 8

Non-keratinised stratified squamous cells

Question 9

The Nephron

Answer 9

Structural and functional units that form urine— Approximately 1 million per kidney

Question 10

Functions of the nephron

Answer 10

• Filtering the blood
• Reabsorbing useful materials from blood filtration
• Secretion of waste into urine

Question 11

Two main parts of the nephron

Answer 11

• Renal Corpuscle

- Renal Tubule

Question 12

Blood vessels of the nephron do what?

Answer 12

• Deliver blood to nephron so I can be filtered

- Facilitate exchange of substances

Question 13

Components of Renal Corpuscle

Answer 13

• Glomerules (a tuft of capillaries) which form a high-pressure capillary bed
• The double layered glomerular (Bowman’s) capsule which wraps around the capillaries;  Visceral layer composed of podocytes

Question 14

Rebuke Tubule

Answer 14

The structure where filtrate is processed and modified into urine

Question 15

Components of the renal tubule

Answer 15

• Proximal convoluted tubal (PCT)
• Loop of Henle (ascending and descending limb)
• Distal Convoluted Tubule (DCT)
• Collecting Duct

Question 16

Proximal Convoluted Tube

Answer 16

• Directly attaches to corpuscle
• lined with simple cuboidal epithelium
• MICROVILLI on a local surface for greater surface area

Question 17

Much of PCT filtrate is reabsorbed

Answer 17

• Especially water, glucose, amino acids and ions.

- Secretion helps to manage pH and rid the body of toxic foreign substances

Question 18

Purpose of Loop of Henle

Answer 18

Works to establish salt concentration gradient in the medulla to promote recovery of water from filtrate

Question 19

Loop of Henle (descending limb)

Answer 19

Freely permeable to water, but not salt

Question 20

Loop of Henle (ascending limb)

Answer 20

Impermeable to water, but permeable to salt

Question 21

Function of Distal Convoluted Tubule

Answer 21

• Functions more in secretion than reabsorption.

- Recovery of water and sodium is influenced by hormones: aldosterone and antidiuretic hormone (ADH)

Question 22

Glomerular Filtration Rate

Answer 22

Amount of filtrate formed by both kidneys each minute.

Homeostasis requires kidneys to maintain a relatively constant GFR.

Question 23

Juxtaglomerular Apparatus (JGA)

Answer 23

• Important in regulation of filtration formation and blood pressure.
• Regulates blood pressure in the kidney in conjunction with the ANS

Question 24

JGA in DCT: Macula Densa

Answer 24

• Cuboidal cells which monitor fluid compensation (Na+)

- Single non-motile cilium monitors flow rate

Question 25

JGA in Afferent arteriole

Answer 25

Juxtaglomerular (granular) cells:

Modified smooth muscles cells that can contract and relax, has baroreceptors and releases renin.