Equine Reproductive Anatomy - Male Flashcards

1
Q

What is the source and role of GnRH (male)

A

Hypothalamus

stimulate pituitary to secrete FSH/LH

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2
Q

What is the source and role of FSH (male)

A

Pituitary

stimulate Sertoli cells to mature sperm

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3
Q

What is the source and role of LH (male)

A

Pituitary

stimulates leydig cells to release testosterone

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4
Q

What is the source and role of testosterone (male)

A

Testes (leydig cells) and adrenal glands

stimulate sertoli cells to produce sperm

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5
Q

What is the source and role of oestrogen (male)

A

Testes (leydig cells)

regulation of laminal fluid

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6
Q

Are males seasonal breeders

A

Yes - long day breeder

sperm production all year but quantity/quality poor

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7
Q

Describe testes morphology

A
  • ovoid shape
  • sit in inguinal region horizontally
  • 10cm length average
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8
Q

Describe testicular development

A
  • start in abdomen and decend into scrotal position

- right decends first

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9
Q

Why is it important to check if testes descended

A

problem when one is retained in abdomen
need lower temperature for sperm to survive, too hot at body temperature in abdomen
maintain at 35-36 celcius

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10
Q

Cryptorchid and rig

A

= one testes decended and one inside retained testicle
abdominal pressure doesnt push testes down through ingunor canal
= castrated one testicle, one remain

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11
Q

How to check if testes descended/are there

A

feel for testicle
test testosterone levels
HCG test
blood test for oestrogen sulfate in leydig cells (oestrogen higher in stallion)

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12
Q

What is the HCG stimulation test

A

inject horse with human chorionic gonadotropin
high level = stallion with testes
low level = no testes

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13
Q

What is androgen-binding hormone

A

glycoprotein produced by sertoli cells and binds to testosterone. keeps testosterone at elevated level in seminiferous tubule

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14
Q

What temperature should testes maintained and how adapted to do so

A

30.5-32.5 celcius
external location close to body wall
scrotal skin - contains sweat gland to aid temp regulation

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15
Q

What is the tunica dartos, cremaster muscle and pampiniform plexus

A

lining of muscle within the scrotum which contracts (testes closer to abdomen, reduce scrotal surface and heat loss) and relaxes to temperature regulation

moves testes up/down/sideways also for temp reg and protection

formed by dense cappilary network where arterial and venous supplies come into close contact
- warm blood enter testes by artery loses heat to cooler venous return

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16
Q

Where and how testes suspended

A

from abdominal cavity wall by spermatic cord which contains blood vessels, nerves and ductus deferens

17
Q

What is the ductus deferens

A

transports sperm from testes through penis

between epididymus and urethra (through spermatic cord, abdomen and ampulla

18
Q

What is pampiniform plexus

A

site where artery and vein intertwine
temp reg = form of heat
at the most cranial aspect of testes

19
Q

What is the tunica albuginea

- lobes

A

fibrous layer that arises from peritoneum covering spermatic cord, testes and epididymis
provide support to suspended testes
- sheets of tunica albugina divide into lobes
- each lobe is mass of convoluted seminiferous tubules with intertubular areas
- each area responsible for oneof 2 functions ~ gameotogenic (sertoli cells and SemT) or ~ steroidogenic (leydig cells and intertubual tissue)

20
Q

Describe the testes internaly

A

composed of semineferous tubules
embedded with supportive tissue (leydig cells)
semineferous tubules lined with sertoli cells where spermatogenesis occurs

21
Q

Claudin 11 in spermatogenesis

A

expresed by sertoli cells
role = tight junction formation in the testis, helps the sertoli cells for the blood testis barrier, if absent stops spermatogenesis progressing past meiosis and leads to infertility

22
Q

What is the epididymis

A
seminiferous tubules empty into it
lies dorsally over testes
cylindrical 70cm
Caput(head)/Corpus(body)/Cauda(tail) 
surrounded by muscle to aid sperm movement
23
Q

What is the urethra and corpus spongeosum

A

excretory canal for urine and semen
surrounded by striated muscle - contracts during ejaculation
surrounded by corpus spongiosum (spongy tissue that aids erection)
urethra opens within urethral fossa at the end of glans penis w/urethral process projecting beyond glans

24
Q

What are the seminal vesicles

A
  • lie adjacent to neck of bladder
  • add seminal plasma and nutrients to semen via urethra ~ (SP) high conc of potassium, citric acid and gel
  • volume of secretion depends on testosterone cocs
  • 15-20cm long 5cm wide
25
Q

What is the prostate

A
  • bilobed structure with single exit to urethra
  • situated between bulbourethral glands and ampulla
  • H-shaped gland
  • produces alkaline secretion to buffer acidic urine before and during ejaculation
26
Q

What are the Bulbourethral glands

A
  • lie either side of urethra near ischial arch
  • secrete pre-ejaculatory fluid to flush urethra of urine and bacteria and thick mucous (lubrication)
  • contain lots of fibrous connective tissue
27
Q

Penis - physical structure

A
  • cylindrical, muscular
  • extends from ischial arch of pelvis to the umbilicus
    root body and shaft
  • resting = lies retracted within prepuse and held by retractor muscle
  • 50cm length and 2.5-5cm diameter (not erect)
  • many sebaceous glands within folds of prepuce - build up of smegma
28
Q

Penis - root

A
  • attatched to pelvis via ischiocavernous muscles

- bulbospongious muscle covers root and ventrally w/in penis around urethra

29
Q

Penis - body

A
  • composed mostly corpus cavernosum - spongy tissue that becomes engorged (swell with blood)
  • corpus spongiosum - spongy tissue that surrounds urethra (also engorges), surrounded by bulbospongious muscle ~ contained w/in tunica albugina
  • contains erectile tissue
  • haemodynamic = responds to blood pressure
30
Q

What is the glans penis

What is strange about the retractor muscle in stallions

A

enlarged free end of penis, filled with nerve endings and where fossa glandis located

under-developed
ventral to bulbospongiosus muscle

31
Q

What cell no. increases during breeding season and why

role of sertoli cells

A

setoli cells becuase increase in seminiferous tubule length

  • aid sperm development
  • form blood testis barrier (claudin 11)
  • phagocytic (digest degenerating germinal cells
  • secrete luminal fluid and proteins
32
Q

Where is sperm stored

A
  • cauda epidydimis
  • if not passed up vas deferens as result of ejaculation, degenerate and absorbed overtime = allow fresh supply of sperm available
33
Q

What are the vas deferens

A

= connects epidydimis to urethra, passing the accessory glans and into penis

  • thick muscular wall w/ 3 layers ~ inner oblique ~ middle circular ~ outer longitudinal = propell sperm and surrounding fluid by peristalsis (wave muscle contractions)
  • lumen = small and folded ~ maximise surface area aiding sperm storage and reabsorption of testicular fluids
34
Q

What is the ampulla glands and why important

A
  • glands paired outfoldings of vas deferens where meets the urethra
  • secretions high in ergothionine = antioxidising agent that cleans up toxic by-products of sperm metabolism
35
Q

What is seminal plasma and role

A

= major fluid fraction of semen

  • provision of energy and protection of sperm form changes of pH, osmotic pressure and oxidisation
  • contains gel which forms partial clot in semen
36
Q

What are accessory glands

A

4 glands

  • bulbourethral
  • seminal vesicles
  • prostate
  • ampulla

primarily responsible for secretion of seminal plasma

37
Q

What is prepuse and retractor muscle

A

= double folded covering to penis
- w/in inner fold lies glans end penis

  • runs along bottom of penis
  • contraction returns penis to prepuse