Male. Carnivore External Genitilia Anatomy Flashcards
What does the male reproductive tract consist of?
—Paired testes
• Production of gametes & hormones
—Paired gonadal tracts
• Epididymis, ductus deferens
• Link to urethra
—Accessory glands
—Urethra
—Penis
Name the structural components of male repro tract
On anki
What are the 4 accessory glands found in male repro tract
Ampulla, Prostate, Bulbourethral gland & Vesicular glands
Functions of male repro tract
Production of:
• Gametes/ spermatozoa
• Androgenic hormones (testosterone)
• Semen- supportive fluid which keeps sperm alive as it travels through female repro system
Introduce sperm to female repro system
Name the external genitalia
• Penis
• Prepuce
• Scrotum
•Testes
Canine penis
-_______________ type
-contains _________ _______ tissue & ________ ______ tissue
• Musculo-cavernous type
- contains Cavernous sinus tissue & Extensive erectile tissue
Penis is made up of 4 main structures;
Root
Body
Glans (bulbus ad pars longa gland is)
OS penis
Penis root and body formed from…
2 crura
- Arise from ischial arches
- Combine & form single body
- Urethra incorporated at junction of crura
(Image on anki)
2 types of cavernous tissue
Corpus cavernosum
Corpus spongiosum
Corpus cavernosum
-what is it
-formed where?
-feature of it
-distal end becomes…
-type of cavernous tissue
-formed in crura of penis
-left & right corpus cavernosum remain divided by septum
-Distal end of corpus cavernosum becomes os penis
What is the tunica albuginea? (the one found in penis- there’s 2!)
Casing which surrounds the 2 types of corpus in the crura
Corpus spongiosum
-formed from…
-begins at…
-expands what way
-formed from vascular sleeve around urethra
-begins at bulb of penis
-expands distal to corpus cavernosum to. Form glans
Show where the corpus cavernosum and corpus spongiosum are found
(On anki)
Os penis
-forms from…
-why is it a common site for lower urinary tract obstruction?
Forms from distal end of corpus cavernosum
Contains ventral urethral grooves which encloses urethra as it passes the distal penis. Grooves make it difficult for bladder stones to pass through as urethras ability to expand has been prevented, this causes blockage commonly in dogs.
Glans
-formed from…
-2 parts
Formed from corpus spongiosum
-divided into 2 parts internally and externally; bulbous glandis (bulbous part) (proximal expanded part) & pars longus (cylindrical part)
What does the pars longus form? And what does it contain?
-forms apex of penis and contains urethral orifice
The prepuce
-what is it
-opens in what direction
Invagination of abdominal skin
Opens caudal to umbilicus
What’re the 2 types of layers of prepuce?
Laminate externa and lamina interna
Which glans in penis is more or less slightly attached
Bulbus glandis more and pars longus less
Lamina externa
Outer layer and continuous with skin- basically just skin
Lamina interna
-what is it
-appearance and contains what
-Inner layer; lines preputial cavity and continuous with covering of free end of penis
-hairless and contains lots of lymphoid tissue, smegma-secreting preputial glands
Is the prepuce fused with the penis?
New horns have it fused but should separate before puberty
What are the 2 main problems that can be caused by preputial problems and what can they lead to?
—congenital narrowing of preputial orifice
-prevents extrusion of penis which causes phimosis
—paraphimosis
-inability to retract penis which leads to impaired circulation (must be dealt with quickly)
Name the 4 penile muscles
• Bulbospongiosus (Single) - Continuation of urethralis- carries on as muscular sleeve around urethra
• Ischiocavernosi (paired & powerful) - Arise from ischium & enclose crura
• Ischiourethralis (single)
- Passes to fibrous ring enclosing penile veins
• Retractor penis (paired)
- Arise from caudal vertebrae
- Pass lateral to anal canal & along perineum and teach to penis and region of prepuce. Smooth muscle
Penile anterial supply
-2 major supplies
-internal pudendal artery
-external pudendal artery
(On anki)
Name the 3 branches of internal pudendal artery of penis that supply the penis
Dorsal artery of penis
Deep artery of penis
Artery of bulb
What part of penis does the dorsal artery of penis supply
Both Glans
A little to prepuce
What part of penis does the deep artery of penis supply
Supplies corpus carvonosum
What part of penis does the artery of bulb supply
Corpus spongiosum and proximal part of penis
Name the arteries which come from the external pudental artery and what do they supply
Preputial arteries
-supply dorsal part of penis
-the prepuce
Penile venous drainage
—describe the;
-bulbus glandis
-pars longa & prepuce drainage systems
Bulbus glandis drains through dorsal vein which also collects blood from corpus cavernosum & bulb of penis. This then drains into internal pudental vein
Pars longus & prepuce drain into external pudental vein, but also into bulbus glandis causing same process as already described above
(Diagram on anki)
What do the valves in drainage systems prevent?
Prevent reflux
Describe the 2 stages of Canine penile erection
1st Stage
- Increased blood flow via arteries - Occlusion of venous outflow
- Dilation of cavernous spaces due to arterial pressure
2nd Stage
- Contraction of ischiocavernosus & bulbospongiosus
- Blood forced into cavernous space above arterial pressure (undergo rhythmic contrations)
(Diagram on anki)
What is the “tie” action of dogs
When during mating dog dismounts and faces away from bitch. Corpus spongiosum expands more than corpus cavernosum in the male. Their sex organs are locked together and will not release until the males genitalia (specifically bulbus glandis) stops being swollen. Eventual relaxation of bulbospongiosus allows escape of blood and they are released. You should not tear them apart as it would be very painful
Feline penis
• Musculocavernous
• Remains in embryonic position
- Caudoventrally directed apex
- Urethral groove dorsal
• Prepuce thick & short
- Orifice faces caudally
• Shorter than canine penis
• Os penis present but not commonly seen during imaging
• Small glans with small keratinised spines
• Bulbourethral glands near bulb of penis
• Erection results in cranioventral direction of apex penis
Name components of feline penis
On ankiii
Scrotum- external features
-location
-what is it and what does it contain
Location varies between species; canine= intermediate
And feline= perineal
Thin layer of skin that protects the testicles, important for thermo regulation
contains sweat & sebaceous glands, and various hair covering and a groove between left and right half
Scrotum- internal features/ structures
-Skin lined internally by fibromuscular layer called dartos- a combo of smooth muscle and fibrous skin tissue
-internal septum formed from dartos divides right ad left compartments
-contains testes
-fascia lining which supports vaginal tunic
Name structural components of scrotum
On anki
Vaginal tunic
-what does it do
-2 layers
Encloses spermatic cord (structures that supplies testes), testis and epididymis (covers them)
2 layers- parietal layer (outer) and visceral layer (inner layer)
What is the space between layers of vaginal tunic for?
Small amount of fluid
Communication with peritoneal cavity
Inguinal Canal
-what is it
-functions
-contains…
- Slit between caudal abdominal wall muscles
- Runs between superficial & deep inguinal rings
- Allows transmission of testes to scrotum as animal develops
Contains; - Spermatic cord
- Outpouching of peritoneum
- External pudendal vessels.
Superficial inguinal ring
Terminal end of inguinal canal
Deep inguinal ring
Why is the sheep prostate difficult to find?
The sheep does not have a compact prostate - diffuse prostatic tissue is present, but is within the wall of the pelvic urethra, so not visible on a gross anatomic specimen.
