Repro 2 Flashcards
Do dogs and cats have seminal vesicles?
NO!
T/F: The size of the testes is generally not related to the size of the animal
True
Types of testicular cells
- somatic cells
- germ cells
Interstitium (Inter-tubular) cells
- Leydig cells
- mast cells
- CT
- blood and lymph vessels
Seminiferous tubule (intra-tubular) cells
- peritubular cells
- Sertoli cells
- germ cells
The Leydig cell is the site of _________ in the testis
androgen biosynthesis
These cells are also called supporting cells or the nurse cells
Sertoli cells
Sertoli cells have a ____ population in the seminiferous tubules - they stop dividing in early neonatal peroid
fixed
Tight junctions or the zonula occludens between adjacent Sertoli cells constitute the __________
blood-testis barrier
The blood-testis barrier divides the seminiferous epithelium into ______ and ________ compartments
basal and adluminal
The basal compartment has germ cells in ____
mitosis
The adluminal compartment has germ cells in ______
meiosis
During mitosis and meiosis in the testis, the dividing cells are connected by cytoplasmic bridges. Why?
Allows cells in the same cohort to communicate w/ each other and maintain synchrony of differentiation
What is spermiation?
process by which mature spermatids are released from Sertoli cells into the seminiferous tubule lumen prior to their passage to the epididymis
Residual bodies released from the sperm are phagocytosed by ___________
Sertoli cells
The sperm head consists of ….
nucleus and acrosome
The sperm tail consists of ….
- connecting piece or neck
- middle piece
- principle piece
- end piece
What is the arrangement of microtubules inside the tail of the sperm?
9 + 2 arrangement
9 doublets in a ring with one doublet in the center
T/F: Type A1 cells in the testis can revert to Type A0.
True
It reverts back to a stem cell for sperm production
What is spermatogenesis?
process in which spermatozoa are produced from male primordial germ cells by way of mitosis and meiosis
T/F: Waves of spermatogenesis is a concept in SPACE and the seminiferous epithelial cycle is a concept of TIME.
TRUE!
Note: this is often a T/F question on the test!!!!!!!!
T/F: The duration of spermatogenesis can not be altered by hormonal treatment, changes in temperature, etc.
True
T/F: The duration of spermatogenesis can be easily calculated
true
How is the duration of spermatogenesis calculated?
number of SE cycles x duration of one SE cycle
SE cycle = seminiferous epithelial cycle
What is the importance of cytoplasmic bridges present between developing male germ cells?
To maintain synchrony of differentiation
Factors regulating daily sperm production (4)
- spermatogonial divisions
- seasonal variations (environment)
- cellular degeneration
- hormones
_____________ determine the quantitative yield of sperm.
Spermatogonial divisions
Mitotic divisions controlled by ___________
germ cell/ Sertoli cell ratio
___________ can support only a fixed no. of germ cells
Sertoli cells
“ceiling effect” for sperm output
In summer months, male animals can experience ______ sperm output and sperm motility
decreased
One A1 spermatogonia can result in _____ sperm
512
Optimal thermal environment for normal spermatogenesis is _______, which is approx. 5 degrees C below body temperature
32 degrees C
Scrotum (5)
- relatively thin skin
- sweat glands and sebaceous glands
- lack of subcutaneous layer of fat in the scrotal fascia
- fibromuscular layer in the skin = Tunica Dartos
- intracapsular position of large testicular blood vessels
Regulation of testicular temperature is accomplished by…
scrotum and pampiniform plexus
What fibromuscular lauer in the skin of the scrotum is sensitive to temperature changes?
tunica dartos
Describe the pampiniform plexus in the spermatic cord
The outer membrane of the testicular artery merges with the outer membrane of the testicular vein.
Inflowing arterial blood exchanges heat with outflowing venous blood.
Androgens (4)
- support spematogenesis (maintaienance)
- induce and maintain differentiation of male internal and external reproductive organs
- induce secondary male sex characteristics
- influence sexual behavior
In addition to functions, what do androgens promote? (3)
- protein anabolism
- somatic growth
- regulate secretion of gonadotropins
Functions of FSH in males
- synthesis of ABP, inhibin, activin, and aromatase
- increases LH receptors on Leydig cells
_____ in males leads to the synthesis and secretion of testosterone
LH
___ acts via Sertoli cells to stimulate spermatogenesis (initiation)
FSH
_____ increases the number of spematogonia and spermatocytes
FSH
________ regulates meiosis till pachytene stage
FSH
___ regulates Leydig cell numbers through androgen receptors in interstitial cells
FSH
_____ is necessary for the initiation of spermatogenesis, while _____ is necessary for the maintainance of spermatogenesis.
FSH; Testosterone
______ and __________ reduce FSH secretion
Inhibin and follistatin
_________ increases FSH secretion
Activin
Epithelium of the epididymis?
pseudostratified
The duct of the epididymis is lined by _________ muscle to facilitate sperm movement
smooth
There are three kinds of cells in the epithelium of the epididymis. What are they/
- basal
- principal
- clear
What do basal cells do?
regenerate epithelium
What do principal cells do?
absorb fluid and secrete substances such as alpha glycerophosphorylcholine, sialic acid, and carnitine
The blood-epididymis barrier is formed by _______ junctions between principal cells and creates an anatomical, physiological, and immunological barrier.
tight
What do clear cells do?
phagocytose cytoplasmic droplets
Fluid within the epididymis duct has _______ to keep the spermatozoa quiscent
low oxygen tension
T/F: Spermatozoa lack cytoplasm and organelles to perform normal cell functions
True
Under anaerobic conditions, sperm utilize _________ that is present in abundance in the seminal plasma
fructose
Functions of the epididymis
- maturation of spermatozoa
- storage of spermatozoa
T/F: Spermatozoa released from the seminiferous epithelium are fully mobile.
FALSE!!
They are immotile!!
Where do spermatozoa acquire their motility?
in the epididymis
T/F: The region of the epididymis where spermatozoa gain their fertilizing ability is species-specific.
True
The major site for storage of spermatozoa is the ________
cauda epididymidis
Smooth muscle fibers in the terminal part of cauda epididymidis and vas deferens contract __________
only during ejaculation
How long can spermatozoa stored in the cauda retain fertilizing capacity?
several weeks
On average, spermatozoa are transported through the epididymis in _______ (species dependent)
7 to 16 days
Does increasing the frequency of ejaculation change the transit time through the epididymis?
Yes, it can reduce transit time by 10-20%. However the sperm may not have fully matured though
This fibromuscular duct begins at the tail of the epididymis
ductus deferens
In the ductus deferens, sperm are stored in the _________ portion and _________ movements propel the sperm
proximal; peristaltic
Male Accessory Sex Glands
- pair of ampulla (ductus deferens)
- seminal vesicles
- prostate gland
- bulbourethral glands (Cowper’s glands)
- urethral glands
- preputial glands = modified sebaceous glands seen in rodents
Seminal plasma, or accessoty gland secretions, are mixed with sperm and fluid from the cauda epididymis to form _____ at the time of ejaculation
semen
Semen, the mixture of sperm and seminal plasma, contains what other things to help the sperm survive? (6)
- electrolytes
- fructose = energy source
- ascorbic acid
- vitamins
- proteases
- prostaglandins
Main function of the seminal plasma?
- provide an environment conducive to sperm survival within the female repro tract
- prevent immunologic response in the female
What might be the reason that there is a 1000-fold difference in the amount of citric acid in the seminal plasma than in the blood plasma?
may be involved in maintaining pH in the male and female tracts (vagina is acidic)
What do the prostaglandins in the seminal plasma do in the female repro tract?
- cause changes in cervical mucus
- cause uterine contractions to aid sperm transport
Function of cholesterol and lipids in seminal plasma?
may help keep sperm quiscent until deposited into the female tract
Why is there zinc in the seminal plasma?
inhibits sperm activation
In which species does the male have penile spines on his caudally facing glans penis?
cat
Two types of phallus
- fibroelastic phallus
- musculocavernous/ vascular phallus
The features of this phallus include:
- small blood spaces
- substantial amounts of fibroelastic tissue
- sigmoid flexure
- rapid erection
fibroelastic phallus
What species are examples of fibroelastic phallus?
- ruminants
- swine
What species are examples of musculocavernous phallus?
- stallion
- man
The features of this phallus include:
- large blood spaces
- less fibroelastic tissue
- slow erection
musculocavernous
What causes the erection of the penis?
highly coiled arteries in the cavernous bodies that uncoil
This uncoiling allows rapid passage of large volumes of blood to fill and distend the sinuses
Transport of sperm from cauda epididymidis to the female reproductive tract requires _________ and ___________
erection and ejaculation
There are two stages to ejaculation. What are they?
- emission
- ejaculation
Function of testis and seminiferous tubules?
sperm production
Function of collecting ducts?
transport and storage
Function of epididymis?
transport, maturation, and ejaculation
Function of vas deferens?
transport and ejaculation
Function of seminal vesicles?
secrete thick liquid to transport sperm
Function of prostate gland?
secretes thin alkaline solution to neutralise urine and female system
Function of bulbourethral gland?
secretions may lubricate, flush out urine, or form a gelatinous plug
In ejaculation, what happens during the emission stage?
sperm move from the cauda epididymidis and vas deferens into posterior urethra
Emission is under what type of nervous regulation?
sympathetic autonomic
This is the forceful expulsion of the semen from the penile urethra
ejaculation
What is the function of penile papillae?
stimulate vagina
Which hormone is necessary for the maintenance of penile papillae?
DHT
____________ is necessary for accessory sex glands, while ____________ is essential for external genitalia
Testosterone; DHT
Fertilization occurs in the ________ region of the oviduct
ampulla
T/F: Oocytes live longer than spermatozoa.
FALSE!!!
Spermatozoa live longer than oocytes
These structures of the oviducts contract and direct the ovum into the funnel-shaped opening of the oviducts
fimbriae
Primary barries for sperm to reach ampulla from uterus/ vagina
- mucus secreted by cervix
- peristaltic muscle contractions in the oviducts are directed towards the uterus to transport ovum
- transport of oviductal fluid by cilia towards uterus -against the direction which sperm need to go
Transport of sperm in the female reproductive tract occurs in these two phase
rapid phase and slow phase
General summary of the rapid phase
sperm (dead/alive) arrive at the site of fertilization within 2-10 minutes
What is responsible for the rapid phase/
- myometrial contractions initiated by oxytocin
- prostaglandins in the semen
Why is there oxytocin for the myometrial contractions of the rapid phase?
Female secretes it as a result of coitus
Spermatozoa that arrive within a few minutes after mating _____ fertilize the ovum
DO NOT
Describe slow phase
- Sperm reside for several hours in the cervical crypts, endometrial glands, and crypts in the uterotubal junctions following depostion
- During this time, sperm undergo capacitation
During capacitation: (3)
- cholesterol coat is removed
- channels are established in the acrocome
- loss of ions such as zinc, calcium, magnesium, and sodium
What permits the activation of acrosome?
removal of the cholesterol coat from the sperm surface
What is essential for sperm penetration?
Channels in the acrosome that allow the release of pro-acrosin and hylauronidase
Sperm acquire __________ when they come in contact with secretions from seminal vesicles
Glycodelin-S
During slow migration in the female repro tract, sperm exchange Glycodelin-S with ________
Glycodelin-A and-F
secreted by estrogen-primed uterus and fallopian tube
Function of Glycodelin-A and -F?
bound to head region of sperm to prevent premature sperm acrosome reaction
After capacitation, there are 3 more steps in the slow phase. What are they/
- changes in sperm cell surface proteins = Glycodelin-S to Glycodelin-A and -F
- activation of ion channels on sperm surface
- aquire motility
Why is it essential for the activation of ion channels on sperm surface to occur?
change in pH from acidic to neutral as sperm migrate from cervix to uterus and fallopian tube
____________ is essential for the successful transport of sperm
estrogen-primed uterus
What 2 things allow for sperm transport in the slow phase?
- uterine contrations
- motility of sperm acquired during the process of activation in the female tract
T/F: The majority of sperm will reach the site of fertilization
FALSE!!
Majority WILL NOT!
which chemical of uterine origin initiates lutelysis in most species?
PGF2-alpha
In cows, ovulation occurs in _______ phase of the estrous cycle.
metestrus
