Penis & prostate

Question 1

What are the roles of the penis?

Answer 1

Sexual intercourse - becomes erect and ejaculates semen into the female reproductive tract

Micturition - contains the urethra

Question 2

What are the 3 parts of the penis?

Answer 2

Root
Body
Glans

Question 3

Describe the root of the penis?

Answer 3

• Proximal & fixed part
• In superficial perineal pouch of pelvic floor
• Not visible externally
• 3 erectile tissues (2 crura and 1 bulb)
• 2 muscles (ischiocavernosus & bulbospongiosus)

Question 4

Describe the body of the penis?

Answer 4

• Free part of penis
• suspended from the pubic symphisis
• 3 cylinders (2 corpus cavernosa and 1 corpus spongiosum)

Question 5

Describe the glans of the penis?

Answer 5

• Distal part
• Conical shape
• Formed by distal expansion of corpus spongiosum
• External urethral orifice

Question 6

Describe the erectile tissues of the penis.

Answer 6

In the root - right & left crura and bulb

In the body - the crura form the 2 corpus cavernosa (which are separated by a septum).
The bulb forms corpus spongiosum.

Question 7

What happens in an erection?

Answer 7

The erectile tissues fill with blood as a result of sexual arousal

Question 8

Which erectile tissue compartment of the body of the penis fills to a greater pressure during an erection?

Answer 8

The corpus cavernosa

The urethra runs through the corpus spongiosum, so it fills to a lesser pressure to prevent occlusion

Question 9

Name the muscles of the penis? What part of the penis are they in?

Answer 9

In the root

Bulbospongiosus x2 associated with the root

Ischiocavernosus x2 associated with L&R crura

Question 10

What are the fascial coverings of the erectile tissue in the penis?

Answer 10

Superficial = deep fascia
Deep = Tunica albuginea (forms an individual capsule around each cavernous body)

Question 11

Name the 2 ligaments that support the root of the penis?

Answer 11

Suspensory ligament - connects erectile bodies of penis to pubic symphisis

Fundiform ligament - runs down from linea alba, surrounds penis, attaches pubic symphisis

Question 12

What is the prepuce?

Answer 12

Foreskin - a double layer of skin and fascia at the neck of the glans

Question 13

Blood supply of penis?

Answer 13

Dorsal arteries
Deep arteries
Bulbourethral artery

All branches of the internal pudendal artery

Question 14

Venous drainage of penis?

Answer 14

Cavernous spaces drained by deep dorsal vein

Superficial penis drained by superficial dorsal veins

Question 15

Innervation of penis?

What type of nerves?

Answer 15

S2-S4

Sensory and sympathetic = dorsal nerve (branch of pudendal nerve)

Parasympathetic = cavernous nerves

Question 16

What is the function of the prostate?

Answer 16

A gland that secretes proteolytic enzymes into semen

These enzymes break down clotting factors, which allow semen to stay in a fluid state for easier movement in female reproductive tract

Question 17

What is the structure of the prostate?

Answer 17

Size of walnut
2/3rds is glandular
1/3rd is fibromuscular

Surrounded by fibrous capsule

Question 18

Where is the prostate?

Answer 18

Inferior to neck of bladder

Anterior to ampulla of rectum (used to examine prostate during a rectal exam)

Question 19

What are the zones of the prostate?

Answer 19

CENTRAL
Surrounds ejaculatory ducts

TRANSITIONAL
Central, surrounds urethra

PERIPHERAL
Main body & posterior region

Question 20

Blood supply of prostate?

Answer 20

Prostatic arteries - derived from internal iliac arteries

Question 21

Venous drainage of prostate?

Answer 21

Prostatic venous plexus - drains into internal iliac veins

Question 22

Innervation of prostate?

Answer 22

Sympathetic, parasympathetic & Sensory from inferior hypogastric plexus