Chapter 25 Urinary

Question 1

Functions of the Kidneys

Answer 1

• Regulation of blood ionic composition (Na, K, Cl, Ca and HPO4)
• Regulation of blood pH (H and HCO3)
• Regulation of blood volume
• Enzymatic regulation of blood pressure
• Maintenance of blood osmolarity (water and solutes)
• Production of hormones calcitriol and erythropoietin
• Calcitriol allows you to absorb calcium
• Regulation of blood glucose level
• Excretion of wastes and foreign substances (toxins, drugs, urea, ammonia)

Question 2

Location of the Kidneys

Answer 2

Located in the retroperitoneum and the posterior wall of the abdomen between the T12-L3 vertebrae. Ribs 11 and 12 partially protect.

Question 3

3 layers of Kidney tissue

Answer 3

1. Renal Capsule: deep, smooth, transparent sheet of dense irregular connective tissue that’s also the outer coat of the ureter. Helps maintain the shape of the of the kidney and barrier against trauma.
2. Adipose capsule: middle layer, has fatty tissue surrounding the renal capsule to protect the kidney from trauma and holds it in place.
3. Renal fascia: Dense regular connective tissue, anchors kidneys to the surrounding structures and to the abdominal walls.

Question 4

Internal Anatomy of the Kidney

Answer 4

2 regions

1. Renal cortex (light red, outer)
2. Renal medulla (dark red, inner)
   - The renal medulla consists of several renal pyramids.
   - Renal columns are portions of the renal cortex that extend between renal pyramids.
   - Renal sinus: renal pelvis, the calyces and branches of blood vessels.
   - Nephron filters the blood and makes the urine.

Question 5

Blood and Nerve Supply of the Kidney

Answer 5

Renal artery (red)
Segmental arteries
Interlobar arteries
Arcuate arteries
Cortical radiate arteries
Afferent arterioles
Glomerular capillaries
Efferent arterioles
Peritubular capillaries (purple)
Peritubular venules (blue)
Cortical radiate veins
Arcuate veins
Interlobar veins
Renal veins

Question 6

Anatomy of the Nephron

Answer 6

2 parts

1. Renal corpuscle: filtration of plasma (blood)
   a. Glomerulus (capillary network)
   b. Bowman’s (glomerular capsule)
2. Renal Tubule: filter fluid passes (creates urine)
   a. Proximal convoluted tubule (PCT)
   b. Nephron loop (loop of Henle)
   c. Distal convoluted tubule (DCT).
   - Afferent arterioles supplies the nephrons, efferent arterioles takes it away.

Question 7

Function of the Nephron

Answer 7

To produce urine, nephron and collecting ducts perform 3 basic processes.

1. Glomerular filtration
2. Tubular reabsorption
3. Tubular secretion

Question 8

The Filtration Membrane

Answer 8

1. Fenestration of glomerular endothelial cell: prevents filtration of blood cells, but plasma can pass through.
2. Basal lamina of the glomerulus: prevents filtration of larger proteins
3. Slit membrane between pedicles: prevents filtration of medium sized proteins.

Question 9

Glomerular Filtration

Answer 9

In the glomerulus, blood plasma and small dissolved substances get filtered into the glomerular capsule.
Moves through 3 barriers
1.Fenestration of glomerular endothelial cell: prevents filtration of blood cells, but plasma can pass through.
2. Basal lamina of the glomerulus: prevents filtration of larger proteins
3. Slit membrane between pedicles: prevents filtration of medium sized proteins.

Question 10

Tubular Reabsorption

Answer 10

All along the renal tubule and collecting duct, water ions and other substances get reabsorbed from the renal tubule lumen into the blood.
Epithelial cells along the renal tubule and duct carry out reabsorption.
Proximal convoluted tubules make the largest contribution

Question 11

Tubular Secretion

Answer 11

Occurs along the renal tubule and collecting duct. Wastes, drugs and excess ions are secreted from the peritubular capillaries into the renal tubule, where they end up in the urine.
2 important outcomes
1. Secretion of H+ helps control blood pH
2. Eliminates toxins from body.

Question 12

Urinary Bladder

Answer 12

3 layers
1. Mucosa (Inner)
2. Muscularis (Middle)
3. Adventitia (Outer)
Males: directly anterior to the rectum
Female: anterior to the vagina and inferior to the uterus
Trigone: where the ureters drain the urine into the bladder.

Question 13

Ureters

Answer 13

Transport urine from renal pelvis of one kidney to the urinary bladder

Question 14

Urethra

Answer 14

Females: Opening of the urethra is the external urethral orifice. The wall consists of deep mucosa and superficial muscularis.
Males: passes through the prostate (prostratic urethra), then deep perineal muscles (intermediate membranous urethra) and finally through the penis (spongy urethra).