The Urinary System

Question 1

The Urinary System consist of ?

Answer 1

I. Kidneys
II. Ureters
III. Bladder
IV. Urethra

Question 2

Functions of the urinary system

Answer 2

1-Excretion
– of wastes from body fluids 
2-Regulation of
– blood volume and pressure
– plasma ion concentrations
\+Conserving nutrients
3- Production of hormones/enzymes:
-erythropoietin, which controls erythrocyte production;
-renin, an enzyme that controls blood pressure and blood volume; renin cleaves

Question 3

explain the Structure of the kidneys

Answer 3

–Outer cortex and inner medulla
– The cortex is composed of 2 million nephrons
1. Kidneys are paired bean-shaped organs
enveloped by a thin capsule of connective tissue.
2. Each kidney contains about 2 million nephrons.
A nephron and the collecting tubule into which it
drains form a uriniferous tubule.

Question 4

Nephron functions include:

Answer 4

• Filtration of blood
  • Reabsorption of organic nutrients,
  • water and ions
  • Secretion of waste products into tubular fluid

Question 5

Nephron consists of:

Answer 5

1. renal corpuscle
2. PCT – proximal convoluted tubule
3. loop of Henle
4. DCT – distal convoluted tubule Collecting tubule receives urine

Question 6

explain the Renal Corpuscle – filtration of blood Consists of:

Answer 6

Consists of:
A. Bowman’s capsule with parietal and visceral layers
1. visceral layer consists of podocytes with processes
B. Glomerulus of capillaries Blood is filtrated because of big
pressure due to:
afferent arteriole brings blood to capillaries is twice bigger, then efferent arteriole, taking blood from capillaries
–Processes interdigitate around glomerular capillaries.
-The narrow space between processes is the filtration slit.

Question 7

explain the FILTRATION BARRIER: consist of and mechanism

Answer 7

1. Endothelium of capillary (fenestry)
   • 2. Basal lamina - 3 layers
   • 3. Podocytes (slits)
   —- Through barrier pass wastes, water, small proteins, sugar, salts
   • 150 litres of primary urine per day - by filtration
   • 1.5 litres of urine per day - by reabsorption

Question 8

explain Proximal Convoluted Tubule

Answer 8

-simple cuboidal epithelium with brush border longest tube
- brush border = microvilli
reabsorption of:
a. all glucose
b. amino acids
c. ~85% NaCl & H
b. protein
secretion/excretion

Question 8

explain the Loop of Henle

Answer 8

1. forming hypertonic urine

2. is almost impermeable to water

Question 9

explain the Distal Convoluted Tubule

Answer 9

1. simple cuboidal epithelium
2. cells smaller than PCT
3. lack brush border

– function under
influence of aldosterone
2. absorbs Na+ (and H2O)
3. secretes K+, H+, NH4

Question 10

explain the Urine Production

Answer 10

3 process involved in urine
production
– All of these processes occur in the Nephrons of the kidneys
1 Glomerular filtration
2 Tubular Reabsorption
3 Tubular excretion and secretion
—All nephrons enter to Collecting Tubules Under ADH (vasopressin) reabsorps H2O then continue to pelvis

Question 11

explain the Juxtaglomerular apparatus

Two types or two systems of nephron

Answer 11

a. Juxtaglomerular cells -
modified smooth muscle of afferent arteriole synthesize renin effect: increase Na+ and Cl absorption – distal tubules
b. macula densa of DCT
- cells columnar, able to sense ionic concentration.
c. polkissen cells, additional renin secretion

Question 12

explain the Blood Flow

Answer 12

A. Renal artery
B. Interlobar arteries
C. Arcuate arteries
D. Interlobular arteries

Question 13

explain the stricture of Ureter & Bladder

Answer 13

A. 1. mucosa : a. transitional epithelium b. lamina propria

2. muscularis : a. inner longitudinal b. outer circular
3. adventitia