ANS Midterm 1

production and maturation of sperm structures

testis, epididymis, vas deferens,

Testis

sperm and testosterone production

epididymis

fine, highly coiled tube; on the surface of the testis, sperm is going to *mature* and be stored here

vas deferens (ductus deferens)

one for each testicle; where the sperm goes sperm transport at time of arousal

accessory sex glands

seminal vesicles (vesicular gland), prostate, bulbourethral glands (cowper's gland); make up the fluids that makes up semen to help protect sperm and aid mobility; secrets sugars, buffers, vitamins

ampulla

sperm is stored here right before ejaculation; not all animals have (boars do not have)

scrotum

skin sack that houses the testis; keep the testis cool

ischio cavernosus muscle

muscle contracts and straightens out the sigmoid flexure, this makes the penis erect

retractor penis muscle

brings the penis back into the sigmoid flexure

male reproductive system of poultry

testicles are inside body cavity ( not outside); epididymis; vas deferens; cloaca(no penis); no accessory sex glands

pampiniform plexus

a network of testicular veins and blood vessels; acts as a heat exchanger to remove heat from testes

spermatic cord

attaches the testes to the abdominal wall of the animal; includes the cremaster muscle (testes sink away when hot; pull in when cold)

seminiferous tubules

site of sperm production; (look likes ramen noodles); sertoli cells inside; leydig cells in between;

sertoli cells

aid in the production of sperm; cells found within and lining the base of the seminiferous tubules; force developing sperm to the lumen (center of tubules); form blood testes barrier (no sperm in the bloodstream)

leydig cells

produce testosterone; in between the seminiferous tubules (interstitial cells)

epididymis structure

head (caput), body (corpus), tail (cauda)

hormones

chemical mediators of biological events; synthesised by endocrine cells and travel in bloodstream to target cells

types of hormones

peptide hormones and steroid hormones

peptide hormones

travel through the bloodstream to target tissues, bind to specific receptors and a gene is made or not made

steroid hormones

hormone that go directly into the target cell's DNA and affect gene expression

hypothalamic-pituitary-gonadal axis

hormones produced by the hypothalamus and pituitary that affect the gonads

hypothalamus

produces releasing hormones that end up in the pituitary

anterior pituitary

diff cells make diff hormones; somotrope, cortocotrope, thyrotrope, lactotrope, gonadotrope

somatotrope cells

make growth hormone (somatotropin)

corticotrope cells

produce adrenocorticotropic hormone (ACTH)

thyrotrope cells

produce thyroid stimulating hormone (TSH)

lactrotrope cells (mammotrope)

produce prolactin (PRL)

gonadotrope cells

produce gonadotropins (FSH and LH)

posterior pituitary

secretes oxytocin

Follicle-stimulating hormone (FSH)

male: stimulates sertoli cells in testis

female: induces growth of follicles in ovary

luteinizing hormone (LH)

male: stimulates testosterone production in leydig cells in testis

female: stimulates estrogen production in ovary and ovulation

Gonadotropin-releasing hormone (GnRH)

A hormone released from the hypothalamus that triggers the anterior pituitary to secrete FSH and LH

Factors that affect when GnRH is released

age, weight, puberty, temperature, season; usually starts at puberty

feedback systems

hormone control; output of pathway influences inputs of pathway; positive and negative; maintains appropriate physiological lvls of hormones; causes pulses of hormones

negative feedback

if enough hormone is produced it will stop the synthesis of itself; it will block the beginning of the pathway; more common than + ; ex: testosterone

positive feedback

horomones cause increased secretion of the itself

Hormones in Male Reproduction:

hypothalamus, GnRH, anterior pituitary; FSH -\> sertoli-\>spermatogenesis; LH-\>leydig-\>testosterone-\>various functions

Testosterone

development/maintenance of reproductive organs, more muscle and bone mass, aggressive behavior and libido; negative feedback; causes boar taint

Spermatogenesis

production of sperm; happens in seminiferous tubules; mitosis, meiosis 1, meiosis 2, spermatid, morphological transformation, \= sperm; spermatozoa at different stages at different times so its continuous

spermatogonium

diploid stem cells that are destined to become sperm; on the edge of seminiferous tubules

mitosis

spermatogonium and oocytes increase their numbers this way

meiosis

Cell division that produces gametes (sperm and egg); 1/2 chromosomes than original cell; creates 4 haploid sperm or 1 haploid egg

Spermatogenesis: meiosis 1

primary spermatocyte to secondary spermatocyte

Spermatogenesis: meiosis 2

secondary spermatocyte to spermatid

head of sperm

encased in enzymes (acrosome) to protect it; has nucleus and the genetic material

tail of sperm

midpiece (mitochondria), principal piece, endpiece; helps it be modal

ovary

site of egg production; site of estrogen and progesterone production (carried out by specific cells in the follicle)

infundibulum

lays over the ovary, catches the egg when it is ovulated

oviduct

site of fertilization; squiggly tube

uterus

where the embryo/fetus develops; may have "horns" depending on the species

cervix

structure that creates a barrier for the uterus to keep it clean

vagina

birth canal

vulva

external female genitalia; junction from outside and vagina

reproductive organs of male poultry

testicles (inside body), vas deferens, cloaca, no penis, no accessory glands

reproductive diff of boars

no ampulla, bigger bulbourethral gland (more semen

uterus types

duplex, bicornuate, simplex

duplex uterus

2 cervices; marsupials and rabbits

bicornuate uterus

uterus with two horns; poorly to moderately developed horns (mare and cow); highly developed uterine horns \= big litters (bitch, queen, sow)

reproductive organs of hens

2 ovaries (but only left side develops); 5 parts of the oviducts

hen ovaries

cluster of follicles of different sizes, (egg\=yolk); estrogen and progesterone production

5 parts of oviducts (hens)

infundibulum, magnum, isthmus, shell gland, vagina,

infundibulum of hen

also catches the egg, site of fertilization

magnum

albumen is added to the egg, (egg white)

isthmus

shell membrane is put on the egg; keeps out bacteria and prevents egg from drying out

shell gland

where the shell is formed; where the shell pigment is added

vagina (hens)

birth canal kinda

cloaca

opening for digestive, urinary, and reproductive tracts for poultry

Oogenesis

the production, growth, and maturation of an egg, or ovum; production of haploid gametes

oogenesis process

mitosis to keep numbers; primary oocyte\=meiosis 1 (1 polar body) and one secondary oocyte\= meiosis2 (another polar body), mature egg (

Oogenesis meiosis 1

primary oocyte; division is not equal btn daughter cells\= 1 polar body and 1 egg; female is born with all eggs she will have, eggs enter this stage then egg is frozen; primordial follicle at this stage

oogenesis meiosis 2

egg will become a secondary oocyte; will be ovulated then process will freeze, only complete when egg is fertilized by sperm; graafian/antral follicle

oogonium

cell that is going to be a developed egg

compare meiosis in male and females

male: starts at puberty , continuous, 4 sperm

female: starts in utero, completed upon fertilization; 1 stem cell --\> 1 egg

Folliculogenesis

follicle development: primordial follicles, primary follicle, secondary, teritary, antral or graafian, CL, CA

primordial follicles

present at birth, dormant; flattened layer of cells surrounding egg

primary follicles

single layer of cells surrounding egg, still a primary oocyte

secondary follicles

ovum and 2 layers of cells

tertiary follicles

aka antral follicles; antrum (cavity) forms

Antral or Graafian follicle

ruptures and releases egg \= ovulation, mature follicle (meiosis 1 is going to complete)

corpus luteum

cells from follicle differentiation (luteal cells); produces progestrone; if animal is pregnant, it will stay; if animal is not pregnate it will regress

corpus albicans

The scar tissue that replaces the corpus luteum.

zona pellucida

the thick transparent membrane immediately surrounding the oocyte

cumulus cells

Cells which surround the secondary oocyte on ovulation which the sperm has to penetrate to get to the egg

estrogen

produced by cells in the follicle, drives the behaviors of heat; can causes negative feedback and positive feedback

progesterone

hormone produced by the corpus luteum in the ovary; needed to present to maintain pregnancy cells; negative feedback to block FSH and LH from being secreted so no other follicles grow

theca cells

respond to LH and produce androgens (like testosterone)

granulosa cells

testosterone and FSH acts on it then produces estrogen

Hormones in female reproduction

hypothalamus, GnRH, Anterior pituitary, FSH and LH, FSH--\> granulosa cells, estrogen, LH surge, ovulation; LH--\> testosterone and luteal cells, progesterone

estrous cycle

21 days for cattle, horses, pigs and goats; 17 for sheep, 4-5 for mice

estrous cycle types

* polyestrous (cow); reflex ovulator (cat); seasonally polyestrous (goat); monoestrous (dog); anestrous

luteal phase

corpus luteum is present and progesterone is being produced

follicular phase

follicles is growing and egg is maturing (3-4 days right before ovulation)

estrus

When a female is receptive to be bred; heat; ovulate at the end

metestrus

stage of the heat cycle following estrus when ovulation occurs; corpus luteum forms

diestrus

biggest stage of estrous cycle; corpus lutem is mature; most of luteal phase

Proestrus

between when CL starts breaking down until the animal comes into heat; growth of new follicles; increase of FSH and LH

stigma

place on the follicle with no blood vessels present, LH surge will lead the egg to ovulate from there