AVS 472 Cumulative Exam Practice

testis

primary sex organ

scrotum

thermosensor, radiator, protective sac

tunica dartos

contract testis inwards, smooth muscle, testosterone dependent

gubernaculum

wad of gum shaped, keeps the testis from spinning on its axis, shrinks as they get older

smooth muscle

doesn’t fatigue

skeletal muscle

does fatigue

cross section

cut through the middle, caudal cranial

longitudinal section

cuts in half, dorsal ventral

space between two tunics

open into the body cavity (peritoneal cavity)

tunica albuginea

encases testis

mediastinum

sperm converge to get to tubules

seminiferous tubules

ramen noodle shaped in testis

caput epididymis

head of the epididymus

corpus epididymis

body of the epididymus

cauda epididymus

bottom/tail of the epididymus, sperm is stored here

retes testis

in mediastinum, connects seminiferous tubules

vas Efferent

water reabsorption

number of ejactulates in caudal epididymus

5-7

spermatic cord functions

vascular, lymphatic and nerves; heat exchanger; houses cremaster muscle

cremaster muscle

fight or flight, skeletal muscle

pampiniform plexus

intertwining of blood vessels, counter current exchange of temp and testosterone, and arterial pulse

testosterone concentration unit

ng T/ml

testis arterial pulse

variation is much smaller than what is in systemic circulation

coppers gland

pre-ejaculate, fluid secreting, cleanses urethra

sigmoid flexure

s-shaped, when engorged in blood = straightens which pushes out penis

retractor penis muscle

retracts penis after erection

blood rich sections of bull penis

corpus spongiosum and corpus cavernous

corpus cavernous

more blood rich than corpus spongiosum

movement of sperm

testis > epididymus > tail of epididymus > accessory sex glands > penis

how is the horses testis oriented

horizontal

ram is missing what structure

body of the prostate

boar has a large what

ejaculate and cowpers gland (low concentration of sperm)

horses lack what structure

disseminate prostate

dogs are lacking what

ampulla, seminal vesicles, disseminate prostate or cowpers gland (highly concentrated sperm with little fluid)

what structures is a cat lacking

seminal vesicles and disseminate prostate

what is unique to a cat repro?

fishhooks on tip of penis

what type of penis does a stallion have

muscular-vascular

what type of penis does a bull have

fibroelastic

fibroelastic penis

only gain length and not width

muscular vascular penis

gains length and width

Sertoli cell are also called

nurse cells

Sertoli cells respond to

FSH

leydig cells respond to

LH and produce testosterone

Sertoli cells produce

E2 and inhibin

myoid cell

smooth muscle cell

spermatogonium

stem cells, closest to the basement membrane (one divides - one leaves, one stays, infinite divisions)

pre-sertoli cells secrete

AMH (antimollerian hormone aka female repro tract)

ABP

androgen binding protein

structure unique to only canines

bulbs glandis (sexes become tied)

all species have

retractor muscle

sigmoid flexure is only present in species that have

fibroelastic penis

large glans =

no sigmoid flexure

how long does it take for spermatogenesis cycle to occur

2 months (roughly 60 days)

sperm is not fertile until

reaching the vaginia

spermatocytogenesis

mitotic divisions of spermatogonia

hormone blood concentration first peak

GnRH (medium peak)

hormone blood concentration second peak

LH (highest peak)

hormone blood concentration hump between first peak and second

FSH (lowest peak)

LH causes a high peak of

testosterone slightly after the peak

how many pulses are there in 12 hours

4 pulses

importance of pulsatile secretion of LH

high t2 for spermatogenesis, leydig would become refractory to high LH concentrations, excess t2 thought to suppress Sertoli cells

testosterone synthesis (in leydig cell)

cAMP 2nd messenger system

sequence of spermatogenesis

proliferation > meiosis > differeniation

phase 1: proliferation

mitotic division (spermatogenesis) near the basement membrane

phase 2: meiosis

DNA replication and crossing over

phase 3: differentiation

(spermatogenesis) develops head, flagellum, and principal piece near lumen of tubule

flagellum

tail of the sperm

growth of sperm

spermatogonia > primary spermatocytes > secondary spermatocyte > spermatozoa

spermiation

releasing the spermatozoa from the certoli cells

number of mitotic division

are species dependent (between 2 and 6 which produces 4 to 64 daughter cells)

cytoplasmic bridges form

between the daughter cells

degenerating spermatogonia

apoptosis as high as 75%

things that can impact apoptosis of germ cells

normal, season, disease, trauma or heat, hormone levels

stem cell renewal

keeps spermatogenesis going indefinitely and replenish testis in case of injury, trauma, or high heat

proliferation occurs in the

basal compartment (near basement membrane)

meiosis and differentaition occurs in the

adluminal compartment

three types of spermatogonia

A, I, B

meiotic phase results in

4 haploid daughter cells

number of phases of meiosis

2 phases

four phases of differentiation

Golgi, cap, acrosomal, maturation

Golgi Phase

formation of acrosomic vesicle, migration of centrioles

Cap phase

asrcosome development continues, flagellum elongates

Acrosomal phase

acrosome manchette elongation

manchette

a series of microtubules, associated with nuclear elongation

Maturation Phase

manchette disappears, mitochondria migrates, dense fibers form

how does the sperm tail move?

ATP from middle section

spermiation

sprem finishing development and being released

cytoplasmic droplet

freshly released sperm have this, it moves down the tail as they sperm migrates and eventually falls off

cytoplasmic droplet on sperm indicate what?

an overworked male

stages of spermatogenesis

specific cellular associations within a small segment of the seminiferous tubule

stages differ in

duration (amount of time)

A’gonia present in

every stage of spermatogenesis

Which stage takes the longest?

stage 1 (4.09 days)

which stage takes the shortest amount of time?

stage 5 (0.22 days)

bull spermatogenesis length

13.5 days (one cycle)

number of stages in bull spermatogenesis

8 stages

the duration of the cycle differs

between species

number of cycles in bull spermatogenesis

4.5 cycles

typically 4.5 cycles are required

for A1 spermatogenia to become mature spermatozoa

single cycle day length for ram

10.4 days