Comprehensive Reproductive System and Hormone Regulation in Animals

T/F: Most Management systems for reproduction are based on the female?

True

List the steps of an reproductive cycle IN ORDER

Estrus (Sexually active), Gestation (pregnancy period), Birth, Lactation, Weaning, Rebreeding, back to estrus

What is the primary function of male reproductive anatomy?

Deliver Sperm for breeding

List the organs in a female reproductive system

Ovary, Oviduct, Broad Ligaments, Uterus, Cervix, Vagina, Vulva

True/False: the Ovary receives a rich supply of both blood vessels and nerves

True

what stimulates the growth of follicles?

gonadotropins

what is it called when a follicle dies

Atresia/becomes atretic

After a follicle ovulates, the extra tissue left over can form a...?

Corpus Luteum

what is the primary hormone produced by the CL?

progesterone

What is the primary function of a corpus albicans?

No function; Avascular (no blood vessels) and nonfunctional; scar tissue formed from regression/death of corpus luteum

What is the specialized end of the oviduct called? which end is it? what is its function?

Fimbria; End near the ovary; collects ovulated eggs from the ovary

What is the anterior end of the oviduct? the posterior end?

Ampulla; Isthmus

How many layers of muscle surround the uterus

2

what is the most commom area of fertilization and early embryonic development?

Oviduct

The Cervix has one main purpose and that is..?

To separate the Uterus from the outside environment

Where is semem deposited in most animals? what are the exceptions?

Vagina; some animals deposit in cervix (i.e pigs) and others deposit sperm into the oviduct (i.e. rats/mice)

what is the vulva responsible for?

producing female pheromones and signaling sexual receptivity

what is the testicle made up of?

many tightly folded up tubules

what are the 2 functions of the testicle?

produce sperm and hormones (like testosterone)

what is the epididymus specialized for?

Sperm Storage and Maturation

what organ transports sperm from the Epididymus to the urethra?

Vas Deferens

True/False: Testicles are made up of seminiferous tubules while Epididymi are made up of noniferous tubules

False; Epididymi are a continuation of the seminiferous tubules in the testicles

Name all 3 secondary sex glands and their purposes?

Seminal Vesicles, Prostate Gland, Bulbourethral Glands; produce the liquid part of semen

True/False: all animals with a sheath utilize it in pheromone production

False; while some animals do use their sheaths for this purpose, it is erroneous to say that all animals use it for this purpose

What produces the largest amount of liquid in sperm?

Seminal Vesicles

Which organ releases the hormone that regresses the Corpus Luteum?

Uterus

What are the 3 classifications of hormones in females? their functions?

gonadotropins: stimulate ovary

prostaglandins: control reproductive state/estrus cycle

mammotropins: lactation

What are 2 gonadotropins? what do they do? where are they produced

Luteinizing Hormone (LH): stimulates ovulation & CL, finalizes follicle growth; pituitary gland

Follicle Stimulating Hormone (FSH): stimulates all stages of follicle growth, especially early on; pituitary gland

What are 3 prostaglandins? what do they do? where are they produced

Progesterone: inhibits gonadotropins, maintains pregnancy; CLs and placenta (in certain animals)

Estrogen: controls gonadotropins (both - and +), stimulates surge of gonadotropins that causes ovulation, controls female mating behaviors, & prepares female for breeding and parturition (giving birth); Follicles, Placenta, and Embryos

Prostaglandin F2 Alpha (referred to as prostaglandin): stimulates regression of CL, causes uterine contractions; Uterus

What are 2 mammotropins? what do they do? where are they produced

Prolactin: stimulates milk production; pituitary gland

Oxytocin: stimulates milk excretion & uterine contractions; Uterus & Hypothalamus

Define Puberty. what is the criteria for males? females?

the age at which animals are capable of adult reproductive function

Males: libido (fertile sperm & sex drive)

Females: estrus (fertile eggs & maintenance of pregnancy)

What matures last in puberty? why?

Brain; specifically production of LH

T/F: once LH production begins, ovaries and testes are able to produce gametes and hormones

False; both are capable of producing gametes and hormones prior to the brain gaining the ability to produce LH

Describe which hormones are high/low at Estrus

High: Estrogen

Low: Progesterone

what specifically causes ovulation?

the surge in LH due to high estrogen

what happens after ovulation?

Estrogen decreases, CL is formed, progesterone increases

what happens after formation of CL?

it is maintained for 12-16 days, then, if nonpregnant, uterus releases prostaglandin, which regresses the CL. If pregnant, embryo will signal the mother, and prostaglandin will not be released

what happens after the destruction of the CL?

progesterone decreases, Estrogen, LH and FSH increase

when do females realize they are pregnant? why?

~12 days; embryo signals mother

unipotency vs. totipotency?

unipotency: differentiation has occurred; cells can only develop into a specific tissue; after 8 cell stage

totipotency: differentiation has not occurred; single cell could develop into complete animal; 8 cell stage and before

describe the parts of a blastocyst

blastoceole: interior

trophoblast: "wall" of cells that forms blastocyst

inner cell mass: cell mass connected to trophoblast

what will each part become?

ICM: fetus

Trophoblast: placental membranes

Embryo vs. Fetus?

Embryo: before differentiation has begun; no defined shape/form

Fetus: after differentiation has begun (still differentiating); takes shape/form of animal

describe the increases in length and weight of a cow fetus

length: linear

weight: exponential

T/F: parturition is initiated by the mother's uterus

False; initiated by the fetus

what happens to hormones during parturition

Prostaglandins are released, Progesterone decreases,

How does the fetus initiate parturition?

by pressing against the cervix, pressure receptors send signals to the pituitary gland, and oxytocin is produced, which stimulates uterine contractions; Ferguson Reflex (neural reflex arc)

Explain Lactation

when the nipple is stimulated, the brain produces prolactin (milk synthesis) and oxytocin (milk excretion/ejection)

T/F: the baby will have to suckle for a few minutes (~1-2) before getting any milk since it must wait for prolactin to synthesize milk

FALSE; while sucking the nipple releases both prolactin and oxytocin, prolactin produces milk for the next meal, while oxytocin releases the milk for the current meal

Explain rebreeding

the suckling action of the young inhibits LH and FSH. after weaning, LH and FSH increase again and Estrus results

what is the term for sperm production? what causes it?

spermatogenesis; caused by gonadotropins (FSH and LH)

Do gonadotropins stimulate the production of testosterone?

yes, and LH does most of it

How many days does it take for sperm to mature? where is mature sperm stored?

35-42 days; stored in tail of epididymi

Define mRNA and microRNA

mRNA: messenger RNA; template used to build amino acids into chains (proteins)

microRNA: blocks or disrupts protein production

define Genomics

genetic composition of animals

define Epigenetics

heritable changes in gene expression that are not caused by DNA changes

define Proteonomics

proteins produced by a specific genome (set of genes)

what are 2 examples of a genomic difference?

a different gene/allele

a different association between a group of genes

what is the primary way a phenotypic difference can be caused by an epigenetic difference?

a gene is turned on or off (expression of a gene is limited/allowed) (i.e. DNA methylation patterns)

what is the primary way a phenotypic difference can be caused by a proteonomic difference?

differences in the amount of proteins produced by a gene or genome

what is the "equation" for phenotype?

genotype + environment = phenotype

Define Heritability

Variation in phenotype that is caused by variation in genotype

T/F: no traits are 100% heritable

False (i.e. eye color, coat color)

Define Epistasis

two genes interacting with one another at different loci (areas) to control a single phenotypic trait

T/F: like 100% heritable traits, traits can also be 0% heritable

True

What is the equation for genetic change?

selection differential * heritability

what is the equation for selection differential?

((superior M - herd avg M) + (Superior F - herd avg F))/2

what is the equation for inbreeding coefficient

.5( Σ(.5)^n)