All these (w)hormone concepts (Repro Key Concepts)

With regards to the HPG axis, what does the Hypothalamus secrete?

Gondatropin Releasing Hormone (GnRH)

Where is Follicle Stimulating Hormone and Luteinizing Hormone secreted from?

anterior pituitary

What hormones are secreted from the posterior pituitary?

Secretes Vasopressin and Oxytocin

With regards to Vasopressin and Oxytocin, what specific structure makes these hormones and where are they stored until release?

paraventricular nuclei (PVN) of the hypothalamus but stored in pituitary until release

What does the male and female gonad secrete?

male: testosterone

female: Estrogen and Progesterone

Estradiol/Estrogen - ______ feedback during ovulation induces ____ ____

but has _____ feedback during folliculogenesis to suppress ___ _____

positive

LH surge

negative

FSH secretion

What type of feeback loop does Progesterone and Testosterone have?

negative

T/F All gonadotropins have the same alpha subunit but have different beta subunit.

Which one of the subunites is the one that confirms biological activity?

true

beta subunit

What drives ovulation in the female?

LH surge

What does LH do in males?

stimulate the secretion of testosterone

What drives the secretion of LH?

caused by pulsatile secretion of GnRH

T/F FSH is responsive to GnRH but doesn't follow pulses as closely as LH

True

What does FSH stimulate in males and females?

females: promotes growth of follicle

males: promotes spermatogenesis

All steroid hormones are _____ based hormones that are converted to progesterone, testosterone, and estradiol by _____

cholesterol

enzymes

What converts testosterone to estradiol?

Aromatase

What converts testosterone to dihydrotestosterone (DHT)?

What is dihydrotestosterone (DHT) known as?

5a-reductase

DHT is the active form of testosterone

What are seasonal breeders based on?

photoperiod and temperature

The ____ ____ secretes melatonin to activate the HPG axis and induce GnRH secretion

Pineal gland

The uterus is composed of a body and two horns, what are the 3 layers in order from inside out?

Endometrium (mucosa + submucosa)

Myometrium (smooth muscle)

Perimetrium (serosa)

What creates the oocytes and how many meiotic divisions does it take?

Oogenesis

two

T/F All oocytes are generated before birth

True

What are the events of Meiosis I?

Occurs just before ____

Concludes with one ____ oocyte and one ____ ____

(Diploid/Haploid)

ovulation

secondary

polar body

diploid

What are the events of Meiosis II?

Occurs at _____

Creates a second _____ ____

(Diploid/Haploid)

fertilization

polar body

haploid

What makes up the follicular phase?

made up of proestrus and estrus stages of estrous cycle

What occurs during the follicular phase? (not a trick question)

Folliculogenesis

What does Folliculogenesis start with?

primordial follicle

(one oocyte surrounded by a single layer of granulosa cells)

When are all primordial follicles formed? They remain in arrested until when?

before birth

puberty

What follicle comes after the primordial follicle?

What stimulates the growth of this follicle?

What cells begins to show here?

primary

FSH

theca

What follicle forms after the primary follicle? What events occur in this phase?

secondary follicle

Granulosa cells proliferate rapidly

Theca cells organize

Zona pellucida forms

When the Theca cells organize, what do they split into and what does each one of these layers do?

Theca interna - secrete hormones

Theca externa - highly vascular connective tissue

What is the final stage of folliculargenesis?

What events occur here?

Large _____ filled with fluid

Large follicles outcompete other follicles by secreting _____ to feedback onto ____ _____. No more secretion of ____ which stops further growth of smaller follicles.•

Smaller follicles undergo _____

antral follicle

antrum

estradiol

anterior pituitary

FSH

atresia

Atresia is driven by ______ and ______

androgens

progesterone

What are the theca interna cells stimulated by? What do they secrete?

Theca interna - stimulated by LH. Produce androstenedione and secrete to Sertoli cells

T/F Before ovulation, Theca interna cells contract to increase intrafollicular pressure to aid in ovulation

False, theca externa

What are granulosa cells stimulated by? What do they do?

stimulated by FSH. Convert androstenedione to estradiol

What is the theory of how supporting cells of ovary/testis work together to stimulate folliculogenesis/spermatogenesis called?

2-cell, 2- gonadotropin" theory

Theca cells analogous to _____ cells in testis because they are both stimulated by __ to produce _____

Leydig

LH

androgens

______ cells analogous to Sertoli cells in testis because they are stimulated by ___ to convert ____ into ____

Granulosa

FSH

androgens into estradiol

During Recruitment, ____ stimulates follicle growth, LH is (low/high) during recruitment of follicles to grow

FSH

low

Durning selection, the follicle grows and secretes ______. This feedbacks to the hypothalamus to stimulate secretion of ___ from pituitary.

estradiol

LH

T/F FSH begins to wane during the selection phase

True

During the dominance ( ;) ) phase, _____ secrete high levels of estradiol. FSH levels dramatically (increase/decrease). (High/Low) estradiol drives (high/low) levels of LH.

Preparing for ____ ____

follicles

decrease

high

high

LH surge.

What is ovulation caused by?

LH surge

Ovarian ______ causes elevated blood flow. Increased blood causes increased _____ around follicle

PGE2

pressure

Theca cells being to produce _____ which stimulates collagenase to weaken connective tissue

testosterone

____ coming from ovary stimulate contractions, adding pressure to follicle

PGF2a

Oocyte is ovulated a ______-_____ complex

cumulus-oocyte

What makes up the luteal phase?

metestrus and diestrus phases of estrous cycle

What drives the luteal phase? (dont overthink it)

progesterone produced by corpus luteum

T/F The luteal phase is a "mock" pregnancy that prevents return to cyclicity to give time for fertilization/early embryogenesis

true

The CL forms __ - __ days post ovulation

3-5

Regarding the CL,

Produces _______

Formation of CL driven by __

Temporary endocrine gland made up of what?

progesterone

LH

connective tissue, theca cells, and granulosa cells

Luteolysis:

If not pregnant, the uterine _____ secretes PGF2a. Stimulates structural regression of CL to become _____ _____

endometrium

corpus albicans.

What is organ critical for luteolysis?

Why?

Uterus

Removal of uterus maintains CL similar to gestation

T/F PGF2a can be injected to stimulate luteolysis and is metabolized by the lungs

True

What makes up the scrotum? (3)

testes, epididymis, and vas deferens

T/F there are 2 phases of testicular descent

true

Regarding the Transabdominal Phase,

Testes attached to _____. Cells of peritoneum form a junction with _____, binding peritoneum and _____ together

gubernaculum

gubernaculum

gubernaculum

Gubernaculum grows and penetrates the ____ ____. Growth forces descent into inguinal canal. Requires ______!

inguinal ring

androgens

Regarding the Inguinal-Scrotal Phase,

_____ descend into inguinal region and the gubernaculum begins to shrink.

Regression of gubernaculum further pulls ____ through inguinal opening

Once the ____ become completely encapsulated by inner layer of peritoneum the gubernaculum fully regresses and forms a small knot at the bottom of the scrotum.

Testes

testes

testes

Animals that have one or both testes that fail to fully descend are known as _______

cryptorchids

T/F Spermatogenesis requires testes to be 4-6 degrees cooler than body temperature

True

What are the three methods to cool the testes?

Pampiniform plexus

Cremaster muscle

Thermosensation of scrotal skin

(if you want more info go to pg 5 i dont wanna type it)

What is the primary reproductive organ in males?

What makes up the parenchyma? (4)

testes

Seminiferous tubules

Leydig cells

Lymphatic vessels

Connective tissues

Where does spermatogenesis occur?

Seminiferous tubules

What are the two compartments of the Seminiferous tubules? What is housed there?

Basal compartment - houses spermatogonia and primary spermatocytes

Adluminal compartment - houses maturing spermatocytes/spermatids(cells undergoing meiosis)

What are the Basal compartment and Adluminal compartment compartments separated by?

blood-testis barrier

What does the blood-testis barrier do? What is it formed by?

immune privileged site for spermatocytes undergoing meiosis

tight junctions connecting Sertoli cells

What are the stages of spermatogensis in order?

Spermatogonium

Primary spermatocyte

Secondary spermatocyte

Spermatid

Sperm

Spermatocytogenesis (proliferation phase),

Cells still in a "____ _____" state. _______ undergo mitosis during this phase. ______ undergo a certain number of divisions. After last division, ______ cross blood-testis-barrier

stem cell

Spermatogonia

Spermatogonia

spermatogonia

T/F In the meiotic phase, the cells are still proliferating and primary spermatocytes immediately being meiosis after crossing blood-testis-barrier.

false, they are no longer proliferating

Meiosis creates __ (#) total _____ cells

____ spermatocytes enter Meiosis I

______ spermatocytes enter Meiosis II

After meiosis II spermatocytes become _____

4

haploid

Primary

Secondary

spermatid

What are the four phases of Spermiogenesis (differentiation phase)? What occurs in each stage?

(long slide so sorry)

1. Golgi phase: Vesicles of Golgi apparatus begin to fuse to create acrosome vesicle → Centrioles migrate to underneath nucleus toeventually become attachment point for tail

2. Cap phase: Acrosome forms a cap over the nucleus → Primitive flagellum begins to form

3. Acrosomal phase: Acrosome spreads to cover top of the nucleus

4. Maturation phase: Mitochondria accumulate around flagellum

What does a mature sperm have?

head, midpiece, and a tail

The head is made up of what three things

nucleus, acrosome, and post-nuclear cap

Mature sperm:

______ contains condensed, cross-linked and inert DNA that will contribute to paternal genome after fertilization

Acrosome filled with _____ _____ necessary to penetrate oocyte

______ - contains mitochondria. Produce energy for sperm movment

Nucleus

hydrolytic enzymes

Midpiece

T/F The mitochondria do not get transported into egg so there is no paternal mitochondrial DNA!

True

T/F Spermatogenesis occurs in cycle so Seminiferous tubules have different cycles of spermatogenesis occurring throughout length of tubule

true

What is the flow of the HPG axis for spermatogenesis?

GnRH → FSH/LH →Testosterone/Estradiol

Regarding Leydig cells:

Stimulated by __

Analogous to _____ ____ in ovary

Convert _______ to ______

Secrete testosterone which gets transported to Sertoli cells

LH

theca cells

progesterone, testosterone

Regarding Sertoli cells:

Stimulated by ___

Analogous to _________ cells in ovary

Convert ______ to ______

Secrete ______

FSH

granulosa

testosterone → estradiol

inhibin

Testosterone from Leydig cells tell Sertoli cells to do what?

initiate spermatogenesis and maintain spermatogenesis

T/F Estradiol and inhibin provide negative feedback to suppress FSH secretion from pituitary

True

Sperm leave seminiferous tubules and enter ____ ____ which "mixes" sperm together

rete testis

Where does the sperm go after the rete testis?

efferent ducts

Where does the sperm go after the efferent ducts?

epididymis

Where does sperm mature? What is it surrounded by that produces rhythmic contractions that transports sperm through the duct?

epididymis

smooth muscle

What are the 3 sections of the epididymis?

Caput (head)

Corpus (body)

Cauda (tail)

What does the head of the epididymis do?

Absorbs rete fluid sperm come into epididymis with to concentrate sperm

T/F In the head of the epididymis, sperm are motile or capable of fertilizing an oocyte

false, are NOT

T/F In the body of the epididymis, sperm isolated from corpus are considered moderately capable of fertilizing an oocyte

true

The sperm in the tail of the epididymis have a high potential of what?

fertility

Where do the sperm remain until ejaculation?

in the tail of the epididymis

T/F If no ejaculation occurs for several days, smooth muscle will periodically contract to move old sperm to ductus deferens and urethra to be flushed out during urination

true

What are the 4 accessory sex glands?

Ampulla, seminal vesicles, prostate gland, bulbourethral glands

What are the function of seminal fluid?

contains ______ ______ for sperm

protectants that protect sperm from female immune response/ (high/low) pH environment

_______ and liquefying agents

energy source

low

coagulants

The following description describes what type of penis?

Large blood spaces, less fibroelastic tissue

Slower erection, more blood accumulation

What species is this penis type found in?

Musculocavernous

stallion, dog, man

The following description describes what type of penis?

Smaller blood spaces, more fibroelastic tissue

Relies on sigmoid flexure to retract penis inside body until erection

Rapid erection, little blood accumulation. Relies on relaxation of sigmoid flexure.

What species is this found in?

Fibroelastic

bull, boar, ram

Regarding erection,

After stimulation, sensory nerves activate reproductive behavior center located where?

hypothalamus

Parasympathetic nerves innverate what?

What do the Parasympathetic nerves terminals release?

penile arterioles

nitric oxide