Penis/Prepuce

Question 1

What is the penis?

Answer 1

The penis is a copulatory organ that delivers semen into the female reproductive tract during mating.

Question 2

What are the three parts of the penis?

Answer 2

Root (Base), Body (Shaft), Glans (distal head)

Question 3

What attaches the root of the penis?

Answer 3

The root of the penis attaches to the ischial arch.

Question 4

What are the sections of the root of the penis?

Answer 4

The root has 3 separate sections: 2 tapering crus and a central bulb.

Question 5

What muscle groups are found in the root of the penis?

Answer 5

The root contains 2 distinct muscle groups: Ischiocavernosus m and bulbospongiosus m.

Question 6

What are the main tissue types in the body (shaft) of the penis?

Answer 6

Corpus cavernosum (dorsal) and Corpus spongiosum (ventral).

Question 7

What happens to the tissues in the penis during erection?

Answer 7

These tissues fill with blood during erection to make the penis rigid.

Question 8

What does the glans penis contain?

Answer 8

The glans penis contains only Corpus spongiosum and the urethral opening (meatus).

Question 9

Why is the glans penis important?

Answer 9

It is highly sensitive, and stimulation of this area is crucial for ejaculation. The shape of the glans and urethral opening are highly variable across species.

Question 10

What is the blood supply to the penis?

Answer 10

All blood supply to/from the penis is via the pudendal vessels (mainly the internal pudendal).

Question 11

What are the major vessels within the penis?

Answer 11

Dorsal a + v, Cavernous a, Bulbo urethral a + v. The circumflex vessels wrap around the sides of penis.

Question 12

What are the ligaments of the penis?

Answer 12

Suspensory ligament (root to pubic symphysis) and Fundiform ligament (root to linea alba).

Question 13

What are the two types of penises?

Answer 13

Musculocavernous and Fibroelastic.

Question 14

What characterizes musculocavernous penises?

Answer 14

Musculocavernous penises are found in the man, dog, tom, and stallion. This type contains more erectile tissue - Large volume of c cavernosa. Blood increases penis diameter and length during erection. Retractor penis m relaxes (levator scroti m in cats) during erection - comes out of body/prepuce.

Question 15

What characterizes flexiform penises?

Answer 15

Found in bulls, rams, and boars. Contains less erectile tissue - limited c caernosa.
Has a sigmoid flexure that straightens during erection.
Retractor penis m relaxes during erection comes out of body/prepuce.

Question 16

Describe the dog’s penis?

Answer 16

The dog has a musculocavernous penis. The glans penis is unique as it contains the bulbus glandis, pars longa glandis, and os penis/baculum - ossified c cavernosum.

Proximal: typical c cavernosum and c spongiosum

Distal: os penis, bulbus glandis and then pars longa glandis

Bulbus glandis creates a blockage when engorged

Question 17

What is the function of the bulbus glandis?

Answer 17

It creates a blockage when engorged.

Question 18

what are these

Answer 18

Question 19

Answer 19

Question 20

Answer 20

Question 21

Answer 21

Question 22

Answer 22

Question 23

Describe the prepuce of the stallion and boar

Answer 23

Question 24

Describe the prepuce

Answer 24

The prepuce/prepucial sheath is a pouch of skin which houses the glans penis in most species. There are 2 layers of the prepuce. 1. Outer parietal layer continuous with skin, 2. Inner visceral layer continuous with penis. The frenulum connects the proximal glans to prepuce in immature animals and absent in males.Blood supply is via ext pudendal vessels.

Question 25

Differentiate penises between the Bull Ram Boar Dog Tom Stallion

Answer 25

Question 26

Describe the muscles of the penis (LA)

Answer 26

The base/root of the penis contains 2 muscle groups: Ischiocavernosus muscles - 2 x one on each crus. These contract to keep blood in the c. cavernosa during erection. The bulbospongiosus muscle 2 x on each side of the bulb, contract to help empty urethra, connect penis to ischial arch. The urethralis m surrounds the upper pelvic urethra distal to the penis. Contraction of the urethralis m causes the movement of sperm and seminal plasma into the penile urethra. The retractor penis muscle runs from the caudal vertebrae along the ventral length of the penis. Contraction causes the penis to retract within prepuce. Relaxation allows the penis to extend outside of body/prepuce.