7. Anatomy of the Urinary System Part II

Question 1

Urethra (3)

Answer 1

1) Thin-walled muscular tube

2) Carries urine from the bladder out of the body

3) Mucosal lining of urethra
a) Starts as transitional epithelium
b) Becomes stratified columnar towards exit

Question 2

Urethra sphincters (2)

Answer 2

1) Internal urethral sphincter
a) Involuntarily controlled
b) Located near the bladder
c) Keeps urethra closed

2) External urethral sphincter
a) Skeletal muscle
b) Voluntarily controlled
c) Surrounds urethra as it passes through the pelvic floor

Question 3

Urethra differences - male vs. female (3)

Answer 3

1) Males
a) Longer than female
b) Carries both semen and urine

2) Females
a) Shorter
b) Carries only urine
c) More vulnerable to infection (UTI) because closer to anal sphincter

Question 4

Male urethra (3)

Answer 4

1) Prostatic urethra
a) Within the prostate gland

2) Membranous urethra
a) Within the urogenital diaphragm

3) Spongy urethra:
a) Runs within the penis, opens to the external urethral opening

Question 5

Nephron (2)

Answer 5

1) Basic structural function of the kidney

2) Functions
a) Controls the concentration of water and soluble materials
b) Eliminates waste from the blood
c) Regulates blood volume, pH, blood pressure
d) Controls level of electrolytes

Question 6

Nephron graphic

Answer 6

1) Glomerular capsule filters blood
2) Renal tubule reabsorbs needed materials and collecting ducts carry remaining material away as urine
a) Proximal convoluted tubule (PCT)
b) Nephron loop (Loop of Henle)
c) Distal convoluted tubule (DCT)
d) Collecting ducts

Question 7

Renal corpuscle (2)

Answer 7

1) Glomerulus
a) Network of tiny blood capillaries
b) Afferent = incoming (much larger)
c) Efferent = exiting

2) Glomerular Capsule (Bowman’s)
a) Surrounds glomerulus
b) Double walled simple squamous epithelial cup

Question 8

Glomerular Endothelium

Answer 8

1) Glomerular capillaries are highly porous

2) Fenestrations (pores) that allow certain substances to leave the capillaries
a) Filtration by size

3) Unique capillaries
a) Afferent arteriole - much larger in diameter
b) Efferent arteriole - smaller

Question 9

Glomerular capsule graphic

Answer 9

Question 10

Glomerular Endothelium - difference in arterioles (2)

Answer 10

1) Filtration made possible by difference in diameter of arterioles
a) Causes high blood pressure in the glomerular capillaries
b) Forces water and solutes out of blood plasma

2) Filtrate once water and solute leaves the blood and enter the capsule
a) Filtrate moves into the tubule portion of the nephron

Question 11

Nephron types (2)

Answer 11

1) Cortical nephrons
a) In the cortex region of the kidney
b) Portion of loop of Henle extends into medulla

2) Juxtamedullary nephrons
a) Longer loops of Henle pass deeply into the inner medulla

Question 12

Filtrate to urine (4)

Answer 12

1) Renal tubule to collecting duct
a) Many together converge to form papillary ducts

2) Calyces

3) Renal pelvis
a) Filtrate called urine once filtrate reaches the renal pelvis

4) Ureter to bladder

Question 13

Glomerular capillaries (Glomerulus)

Answer 13

1) Formed afferent arteriole

2) Leaves as efferent arteriole

Question 14

Peritubular capillaries (3)

Answer 14

1) Arise from efferent arterioles as they leave the glomerulus
2) Follow the tubules and drain into interlobular vein
3) High Porosity, low pressure
a) Adopted for absorption
b) Reclaim water, solutes from filtrate back into blood plasma

Question 15

Vasa Recta (capillaries) (2)

Answer 15

1) Follow the loops of Henle in the juxtamedullary nephrons of the medulla
2) Reclaims water, solutes from filtrate to move back into the blood

Question 16

Micturition (4)

Answer 16

1) Urine accumulates in the bladder
2) Detrusor muscle contracts
3) Internal urethral sphincter relaxes
4) Voluntary relaxation of the external urethral sphincter results in urination

Question 17

Micturition - urination process (3)

Answer 17

1) Urge to urinate
a) Around 200ml of urine
b) Begins the contractions of the detrusor muscle

2) Person can resist urge to urinate because of the external urethral sphincter

3) Eventually if bladder reaches full capacity, the voluntary sphincter will opena nd micturition will occur involuntarily

Question 18

Incontinence (3)

Answer 18

1) Inability to control micturition voluntarily

2) Normal for infants and in later life with medical conditions
a) End-stage dementia

3) Other causes:
a) Emotional trauma
b) Pregnancy
c) Nervous system injuries

Question 19

Urinary retention

Answer 19

Inability to urinate
General anesthesia - detrusor muscle slow to wake up
Common in older men due to enlarged prostate