Urinary System

Question 1

Functions of urinary system

Answer 1

• Removal of toxins metabolic waste and ions from blood

- regulation of blood volume, chemical composition and pH glucogenesis during prolonged fasting

Question 2

Endocrine functions of the urinary system

Answer 2

Renin : regulation of blood pressure and kidney function

Erythropoietin : regulation of red blood cell production (activation of vitamin D)

Question 3

Unary system organs

Answer 3

2 kidneys :remove waste/ excess substances from blood through urination

2 ureters : Move your own from kidneys to bladder

Urinary bladder : temporary storage for urine

Urethra : move urine out of the body

Question 4

Components of nephron

renal capsule

Answer 4

Glomerulus : ball of capillaries afferent and afferent arterial‘s

Glomerular capsule: ( Bowans) double wall chamber surrounding the glomerulus

Question 5

Components of the nephron

( renal tubules )

Answer 5

The renal tubules :

• Proximal convoluted tubule ( PCT)
• Distal convulsed tubule ( DCT)
• Loop of Henle ( LOH)
• Collecting duct ( CD)

Question 6

Process of urine formation

Answer 6

1. Filtration
2. Reabsorption
3. Secretion
4. Excretion

Question 7

What are the 3 major renal processes

Answer 7

Glomerular filtration : movement of plasma across the filtration membrane into the bowmans capsule due to pressure difference ( blood - nephron)

Tubular reabsorption : movement of substances from filtrate back into the blood ( returns glucose, amino acids, water, salt) - (nephron - blood)

Tubular secretion : substances are moved into the lumen of nephron ( blood - nephron)

Question 8

Glomerular filtration rate ( GFR)

Answer 8

Volume of filtrate created per minute by the kidneys ( 120-125 ml/min)

GFR is controlled by 2 totes of mechanisms:

• intrinsic controls ( renal auto regulation)
• extrinsic controls : nervous and enforce one mechanisms that maintain bp, but affect kidney function

Question 9

Extrinsic controls

Under normal conditions at rest ( NS)

Answer 9

Renal blood vessels are dilated & renal auto regulation mechanisms succeed

Question 10

Extrinsic controls under extreme stress ( NS)

Answer 10

Epinephrine & Norepinephrine are released leading to constriction of afferent arterioles, hindering filtration & triggering the release of renin from the granular cells of the Juxtaglomerular apparatus ( JGA)

As a result : stimulates renin- angiotensin mechanism

Question 11

Intrinsic controls

Answer 11

Maintains a nearly constant GFR when mean arterial pressure ( MAP) is in the range of 80-180 mmHg

Question 12

What are the two types of renal auto regulation

Answer 12

1. Myogenic mechanism :
   - High BP leads to constriction of afferent arterioles : helps maintain normal GFR and preorders glomeruli from destroying high BP
   - Low bp leads to dilation of added to arterioles : helps maintain normal GFR
2. Tubuloglomerular feedback mechanism: Senses changes in the juxtaglomerular apparatus ( JGA)