Exam 2 Flashcards
What two species have excess seminal fluid in their semen
Boars and stallions
Why do boars and stallions have a large amount of seminal fluid in their semen
Because they have large accessory glands increasing the amount of plasma produced
What are the three accessory glands
The vesticluar gland, prostate gland, and cowpers gland
What are the three parts of sperm
Head, midpiece, tail
What is the acrosome
The cap like structure on the top of the sperm that protects the nucleus and helps pertrude the ovum during fertilization
What is the capitulum
Connects the midpiece to the head
What is found in the midpiece
Mitochondria and centrioles
What is the midpiece of the head
Equatorial segment which is where the acrosomal ends
What is the apical ridge
Located at the very tip of the outer acrosomal membrane of the sperm important for out growth
What is the mitochondrial helix
The portion of the midpiece that contains the mitochondira important for producing energy for tail movement
What is the axoneme made from
Nine doublets, two inner central fibers, and nine outer fibers
What is the purpose of the axoneme
Contracts the tail allowing it to bend and gives it shape
What is the difference between the principal piece and the middle piece
The principle piece does not contain mitochondria
What is the difference between the terminal piece and the principal piece
There is no coarse fiber
What is the purpose of dynein arms
Assists with the movement of microtubules in the tail of the sperm
What is a primary abnormality
An abnormality that occurs inside the testicle
What is a secondary abnormality
An abnormality that occurs after the sperm has left the testicle
What are some common head abnormalities
Crater defect, tapered heads, ruffled acrosome, and knobbed acrosome
What are some tail abnormalities
Coiled tail, double midpiece, folded tail, and detached head
What are the stages of spermatogenesis
Spermatocytogenesis (mitosis), meiosis, spermiogenesis, and spermiation
What is the purpose of initial cells during spermatogenesis
Providing base cell to start divison
How long is the whole process of spermatogenesis
60-63 days
What is the order of how sperm develops
spermatogonia, primary spermatocyte, secondary spermatocyte, spermatids, and spermatozoa
How long is meiosis 1 and meiosis 2
Meiosis 1 is 21 days and meiosis 2 is 2 days
What are the changes made during the golgi phase of spermiogenesis
The golgi starts forming the proacrosomic granules and the centrioles start migrating to the bottom of the spermatid. The proacrosomic granule turns into the acrosomic vesicle and the centrioles organize into the PC and the DC
What changes start occuring in the cap phase
The acrosomic vesicle starts forming around the nucleus, the inner and outer acrosome membranes form, the rest of the golgi starts migrating down to the bottom of the spermatid, and the axoneme starts froming from the DC
What changes occur during the acrosomal phase
The acrosome fully forms, the mitochondria start drifting to the forming midpiece, and the annulus forms
What changes occur during the maturation phase
The mitochondria move to the midpiece, the golgi starts to dissappear into the droplet, the tail fully develops, and the droplet falls off
What is spermiation
Release of the spermatozoa to the lumen
What is the purpose of the blood testis barrier
To seperate and protect the primary spermatocyte
What three things make up the blood testis barrier
Basement membrane, wall of the blood vessel, and sertoli cells
What does FSH do in the male reproductive tract
Produces testosterone that triggers spermatogenesis w/in the seminiferous tubule
What does LH do in the male reproductive tract
Stimulates leydig cells to produce testosterone
What does the sertoli cell turn testosterone into
DHT
What other hormone does the sertoli cells produce
Estrogen
What is the function of the androgen binding protein
It maintains testosterone levels
What is cumulus granulosa cells
The granulosa cells surrounding the oocyte
What are mural granulosa cells
The granulosa cells surrouding the follicle
What is theca interna layer
The internal layer of theca cells that produces testosterone
What is theca externa
Smooth muslce layer of theca cells
What are antral follicles
Follicles that have developed the antrum
What are primordial follicles
Follicles that have a single layer of squamous pregranulosa cells
What are primary follicles
Follicles that have a single layer of cuboidal granulosa cells
After what stage of folliculogenesis does FSH start to stimulate further growth
Secondary
What three things are critical in the formation of a germline cyst into a primordial follicle
Notch signaling, NOBOX, and Figla
What happens if NOBOX is not present
The germline cyst will not develop into the primordial follicle
What is required for a primordial follicle to develop into a primary follicle
Foxl2
What is required for primary follicles to develop into secondary follicles
GDF9
What does theca cells produce
androstenodione
Describe the two cell two GnRH model
The anterior pituitary produces LH and FSH. The LH stimulates the theca cell to produce androstenodione. The FSH stimulates the granulosa cell to convert androstenodione into estrogen.
What is gonadotropin independent
Initial development occurs independent of GnRH
What is gonadotropin responsive
Follicles can respond to GnRH but GnRH stimulus is not required for follicle growth
What is gonadotropin dependent
Follicles have been stimulated to grow towards ovulation
What is initial recruitment
Primordial follicular pool recruited into the pool of growing follicles in a continuous manner (GnRH independent)
What is cyclic recruitment
A group of antral follicles are recruited to grow towards ovulation during a specific estrous cycle (GnRH dependent)
What allows the LH surge to happen
Atresia
What is recruitment
Refers to the first stage of a follicular wave during which a group of small follicles begin to grow from a pool of antral follicles
What is selection
One follicle is selected to continue to grow and become dependent on LH after estradiol and inhibin have decreased the amount of FSH circulating
What is dominance
The dominant follicle continues to produce estradiol and inhibin preventing the recruitment of the next wave
What are oocytes formed from
Oogonium
What is the purpose of oocytes going thru arrest
So they are able to remain unfertilized for a long period of time and so that only one ovulates at a time
What developmental stages of oogenesis involve mitotic division
PGC, oogonia, and primary oocyte
When do oocytes start individually develop out of their arrest periods eventually undergoing ovulation
Puberty
What causes the meiotic arresst
Increased levels of cAMP
What are the three things that cause an increase in cAMP
Oocytes natural production, cAMP is trasferred from gonad granulosa cells, and cGMP from granulosa cells inhibits PDE
What is PDE and what is its function
Phospho diesterase enzyme and it inhibits cAMP
How do you know an oocyte is undergoing arrest
The germinal vesicle is still present
What is the GVBD phase
When the germinal vesicle membrane gets broken down
How do you know an oocyte is undergoing metaphase 2
A polar body is present
How many polar bodies are present druring fertilization
Two
When an oocyte under go meiosis 2
At fertilization
What causes Metaphse 2 arrest
Cyclin B
What is the only thing that can break arrest
Ca2+ rise initiated by fertilizing sperm
What is follicular/oocyte communication
Gap junctions
What is the gap junction connecting the granulosa cells and oocyte together made of
Proteins called connexons composed of 6 subunits
How are granulosa cells and the oocytre connected
Pores formed by a gap junction connecting their cytoplasm togther allowing for direct communication and transfering small molecules
How are large molecules communicated between granulosa cells and the oocyte
Paracrine secretions
What are the roles the oocyte plays in follicle growth
Secretes GDF9, affects granulosa cell differentiation, energy/metabolic function, follicle cell growth/division, and producing proteins for the zona pellicuda
What is the pressure theory
That as the follicle keeps growing the internal pressure increases causing a rupture aka ovulation
What is the BP theory
BP increases increasing follicular pressure leading to ovulation
What is the smooth muscle contraction contribuation in ovulation
The retraction of smooth muscle increase pressure causing follicular rupture
What is the proteolytic activity theory
Collagenous layer forms around the follicle that enzymes degrade increasing the proteolyic activity of the follicle
What does LH do to cGMP
It increases it in granulosa cells but reduces production and transport to oocytes in ovulatory follicles
What are the two functions of LH
Developing the CL and ovulation
What does LH do to an oocyte
Inhibits the gap junction decreasing cAMP leading to maturation
What are important regulators of ovulation
LH/LH receptor, prostaglandins, progesterone, EGF, and oocyte
What are the three things that occur directly after the LH surge
Increase in BP to ovary/follicle, protein synthesis changes in and around the follicle, and cumulus expansion
What are the four things that directly cause ovulation to occur
Follicular pressure, contraction of smooth muscle, follicular wall weakens, and cumulus expansion
What three things occur during protein synthesis in a follicle
Progesterone is produced, plasminogen activator works, prostaglandin synthesis of PGE and PGF
What is the primary function of the CL
To secrete progesterone
Is the CL permanent
No, it will only stay while pregnant
What are the steps of CL formation
Hypetrophy of granulosa and theca cells, folding of the follicular wall, angiogenesis, breakdown of the basement membrane, pushing of the cells towards the center, and lutenization
What is angiogensis
Formation of new blood vessels giving the red color
What cells get pushed togther to form luteum cells
Granulosa and theca cells
What type of luteal cells do granulosa cells become
Large
What type of luteal cells do theca cells become
Small
What are the four steps to angiogenesis
Basement membrane breakdown, production of angiogenic factors by granulosa cells, mitosis and migration of endothelial cells, and capillary tube formation
What truly stimulates angiogenesis
Production of angiogenic factors
What is the first formation of the CL called
Corpus hemorrhagicum
What is the last stage of the CL called
Corpus albicans
Why is the corpus albicans white
The degrading function of vasoconstriction
What are all the functions of the CL
Secreting progesterone/oxytocin, maintains pregnancy, stimulates mammary development, and controls the ovarian cycle
What does progesterone have a positive feedback on
The mammary gland, the uterus, and the uterus gland
What does progesterone have a negative feedback on
The myometrium (circular and logitudinal layer), the tonic center, and the anterior pituitary
What does the uterine gland secrete
Produces uterine milk to nourish the embryo prior to the placenta forming
What hormone is secreted but the endometrium of the uterus to degrade the CL
Prostaglandin F2 alpha
How does prostaglandin F2 alpha get to the CL if the uterine horn on that side is absent
The prostaglandin has to move through the blood stream of the body being metablized in the lungs which in most species does not leave much prostaglandin to affect the CL
In horses does the uterine horn on the side without the fetus still produce prostaglandin F2 alpha
Yes
What does the embryo do in mares to stop the production of prostaglandin F2 alpha
It moves between both sides of the uterus
Describe the hormonal cycle of estous
The dominant follicle produces estradiol trigging the LH surge resulting in ovulation. Once ovulation occurs the forming CL then starts producing a steady amount of progesterone. FSH is produced in low levels along with estrogen as some small follicles form but are then degraded due to the presence of a CL and the progesterone it produces. If the animal is not pregnant by day 17 the endometrium of the uterus will produce waves of PGF2 alpha to degrade the CL decreasing the amount of progesterone alowing for an increase in estradiol starting the cycle all over again
How long is the estrous cycle and estus in cows
21 days and 18 hrs
How long is the estrous cycle and estrus in ewes
16 days and 35 hrs
How long is the estrous cycle and estrus in sows
21 days and 56 hrs
How long is the estrous cycle and estrus in mares
21 days and 6 days
