animal reproduction 2

What are the model species, why?

Cow, pig, cat, dog, cow, human, rat, chicken, horse

These are the animals with easiest access to study

How can we classify females by reproduction?

Females are the ones that carry and care for offspring

How do our model species differ in their anatomical classification for the uterus, cervix, and vagina

Cervix - what a spiral cervix, cat and dog are smooth, ruminants have rings

Uterus -

What are the anatomical parts and structures of the ovary

Germinal epithelium layer - single outer layer

Tunica albuginea - connective tissue layer

Cortex - outer area

Medulla - connective tissue, blood vessels and nerves

What are the 4 anatomical sections of the oviduct and what are their primary functions

Infundibulum - funnel shape

Ampulla - site of fertilization

Isthmus - thick walled and sperm reservoir

Uterotubal junction - kinks in ruminants and constricts in others

Name the support structures and how is blood supplied to the reproductive tract

Supplied by the ovarian artery

Name the different stages of development for a follicle and following ovulation

Primordial - 1 flat layer of cells / small oocyte

Primary - 1 expanded layer / small picture

Secondary - 2 layers / no antrum / larger oocyte

Tertiary / antral / graafian - 3 or more layers / antrum / larger oocyte

14 give reproductive examples of a neural reflex, neuroendocrine and endocrine response

Neural - standing estrus or milk let down

Neuroendocrine -

Endocrine -

Identify the major reproductive hormones, their classification, basic structure, source, solubility and target tissues

GnRH - a small peptide, synthesized in the hypothalamus, binds pituitary to Gonadotrophs

Oxytocin - small peptide, synthesized in hypothalamus,

LH - follicle growth, anterior pituitary

Inhibin - produced by follicles

Relaxin - small polypeptide, weaken connective tissues

Progesterone - stimulated by LH, required for pregnancy,

Estrogen - ovary, positive feedback

Prostaglandin- induces contractions, produced in uterus

Luteolysis - binds Luteal cells

Pheromones - estrus

Recognize hormone patterns in blood and what factors cause these

Caused by natural life stages, factors, and conditions

What defines reproductive hormone half-life in blood and what clears them?

The time it takes for concentration to reduce by 50%, liver clears them

Give examples of ovarian hormones with positive and negative feedback

Positive - LH, FSH, estrogen

Negative - GnRH,

List the major stages in reproductive steroid synthesis

1. Cholesterol transport

2. Side chain cleavage

3. Transformation

4. Estrogen synthesis

5. Peripheral activation

15 What are the reasons females will or won’t cycle

Cycles when they reach puberty, are in breeding season, and reach recovery in post partum

Reasons for failure - immature, old, out of season, pregnant, postpartum, diseased

What are the distinguishing characteristics for estrus and cycle length in our model species

Stands to be mounted, mucus in vulva, mounting,

What are the 4 phases of the cycle, and what structures and hormones define that stage

Proestrus - rapid follicle growth

Estrus - sexually receptive, ovulation close

Metestrus - recent ovulation

Diestrus - following ovulation, cells luteinize quickly

What are the major hormone patterns at each phase of the cycle

Proestrus - follicle growth

Estrus - estrogen

Metestrus - CH

Diestrus - p4 remained elevated

Why do cycles stop in females with older age

Woman are born with all their eggs, once they’re all ovulated the cycle stops

16 what are the major steps in the reproductive steroid pathway

Cholesterol transport, conversion, progesterone production, theca cell pathway, Granulosa cell, Luteal phase shift

What cells in the ovary are involved in steroid synthesis in the mature follicle

Theca cells, granulosa cells

What hormones control follicle growth and which control ovulation

Follicle growth - FSH, estrogen, LH

Ovulation - LH Estrogen

What type of feedback control occurs during the follicles phase, and what and where is regulated

Both feedback control occurs, regulated in hypothalamus

What if follicle wave development and what types of species display that

Follicle wave development - the synchronized wave like growth of a cohort of Amtrak ovarian follicles

Cattle, horses, humans, sheep and goat

What are the approximate lengths of the follicle phase (proestrus) in our model species

Pig - 6 days

Horses - 6 days

Dog - 9 days

Woman - 14 days

Rat - 3 days

Cow - 3-4 days

Sheep - 3-4 days

Cat - 9 days

What are the major hormones and their patterns during proestrus and at estrus

Estrogen - rises rapidly and peaks at proestrus

Progesterone - reminds at basal levels, gradual rise in very late proestrus

LH and FSH - relatively high early, then decreases

Testosterone - high towards end of proestrus

Explain how reflex (induced) ovulation occurs and which of our model species display this

Ovulation occurs when a signal is sent by stimulation, displayed in cats

What are the hormonal and physical events that lead to ovulation of an egg

1. Follicle stimulating hormone recruits follicles

2. Estrogen surge

3. LH

4. Fina maturation and Luteinization

5. Follicle rupture

17 what is a CL, what does it do, and where did it originate from

Corpus luteum - produced large amounts of progesterone, originates in ovary

What would a progesterone pattern during the estrous cycle of a cow look like and why

Gradually increases peaking at 15 days then decreases, since progesterone peaks at ovulation

What does progesterone do and where does it act

Progesterone thickens uterine lining for imputation and prevents ovulation during pregnancy, supports lactation

What layers define the endometrium

Functional layer and basal layer

What are the 3 stages of change in the uterine endometrium during the estrous and menstrual cycle, and when do they occur

Menstrual phase - days 1-5

Proliferative phase - days 6-14

Secretory phase - days 15-28

What would the major hormone patterns for LH, Progesterone and estrogen look like during a menstrual cycle

LH - remains low and stable, preparing for surge

Progesterone - remains very low, since it’s not being prong follicle

Estrogen - initially low, rises steadily

What is luteolysis and what causes it, and why is it important

The breakdown of CL, prostaglandin causes it, it’s important for cycle regulation

What hormones control myometrial activity (contractions); where do they originate from and what do they do for reproduction?

progesterone, estrogen, oxytocin, prostaglandin, and relaxin

Originate from CL and placenta, they help manage timing of pregnancy and labor

18 where is semen deposited in natural breeding versus AI for our model species

Natural breeding - vagina, cervix for pigs

AI - uterus, cervix for pigs

What are some major differences from AI and natural service

Natural - ejaculation volume larger, much more sperm, duration of fertility not very clear

AI - higher genetic improvement, manually done

What are the 2 primary limits at breeding to fertilization

Timing of insemination and estrus

What is the name of the ovulated egg

Oocyte

Define the major parts of the ovulated egg

Cytoplasm, large nucleus, Zona pellucida

What is fertilization and where does it take place

When sperm penetrates corona cells and egg, occurs in fallopian tube

What are the different stages of embryo development and where does these take place

Embryo stage - uterus

Cleavage stage - oviduct

Blastocyst stage - uterus

What is embryo hatching in our mammalian model species

When the fertilized embryo breaks out of its protective outer shell and implant into the lining of the uterus

For the hatched blastocyst, name the 3 major parts, and which will form the placenta

Attachment, implantation, placentation

What is attachment/implantation and how is pregnancy recognized by the mother in our different model species (or is there a signal at all?)

Embryo stops moving and trophoblast binds endometrium, recognized through hormonal signaling

Identify the membranes surrounding the developing fetus

Amniotic fluid, amnion, allantois, chorion

19 what are the 4 types of placental attachment and which of our model species associate with each

Diffuse - pig and horse

Cotyledonary - cow, ewe

Zonary - dog, cat

Discoid - primates, rodents

What defines the classification for the different types of placental blood supply and why is this relevant

Number of layers between maternal and fetal blood vessels, this is important for immunity

What are the functions of the placenta

Nutrient supply, barrier, prenatal transmission of maternal antibodies

What are eCG and hCG and what do they do in their own species or when used in others

They are used for progesterone production

What are the gestation lengths of the females in our model species

Rat - 21 days

Dog - 64 or more days

Cat - 64 days

Pig - 115 days

Ewe - 150 days

Cow - 280 days

Human - 280 days from last period

Horse - 340 days

What are the 3 stages of parturition and how are they characterized

Stage 1 - preparatory phase, removal of myometrial block

Stage 2 - expulsion of fetus

Stage 3 - expulsion of placenta

What are the important elements that allow a normal delivery

Contractions, pressure breaks membranes, fetus expelled

What is dystocia and what are the consequences to the fetus and mother

Difficult birth, weak fetus or retained placenta

What is the importance of the post partum period to maternal fertility

Uterine must repair

20 why is puberty important for reproducing animals

first indication of breeding capability

What determines the development for the female neuroendocrine system

Puberty

What changes in feedback occur for animals to reach puberty

Hypothalamus can now produce and release FSH and LH to grow large follicles

What factors can influence age at puberty

Genetics, nutrition and body weight, stress

What is seasonal fertility, how is defined and controlled by the natural environment

animals respond to photoperiod and temperature

What is melatonin and when is it released and what does it affect in the reproductive pathway

signals to go to sleeps, released when it’s dark, it synchronizes circadian rhythm with reproductive hormones

What are proceptive, receptive, and refractory estrus behaviors

Proceptive - active in seeking out sexual partners in responds to sight, sounds, smell, and contact

Receptive - stands to be mounted

Refractory - period of refusal during estrus

What are pheromones, what do they do, and how do they act

They’re chemical signals secreted outside the body to attract males

21 how is infertility classified

Non infectious - season, stress, disease, old age, infertile, egg and sperm defects, poor AI timing, reproductive tract defect

Infectious - viral, bacterial

What is a freemartin and why does it occur in cattle

Heifers born twin to a bull will be sterile, placentas fuse and shared blood allows Male androgens from testes masculinize female reproductive tract

Define a retained placenta, how does it occurs, and what may be done

When all or part of the placenta remains in uterus for more than 30-60 minutes, happens when uterine contractions are too weak, to detach it, trapped behind closing cervix, of deeply attached, medication can stimulate contractions or manual removal

Define, a cystic ovary, endometritis, pyometra

Cystic ovary - when cysts develop on ovary

Endometritis - inflammation of the endometrium

Pyometra - life threatening infection of the uterus where pus accumulates inside

What is a leading bacterial disease that affects fertility in some of our model species (what happens to the fetus when infected?)

Leptospirosis, abortion happens

What would the objectives be in controlling female cycles

are they cycling? Last known records for estrus or period, are the expected to be

In women, what are the primary method birth control and how does this work

Pills - ovulation, thick mucus

Mini pills - thick mucus

Depo provera - mucus, ovulation, endometrium

Patch - mucus, ovulation, endometrium

Ring - m o uterus

IUD - prevents sperm transport

What hormones could be useful at inducing a follicle phase; inducing ovulation or inhibiting estrus and ovulation

eCG, FSH, LH

How could synchronization of estrus be accomplished in a randomly cycling group of cows

Progesterone, timed breeding

22 what is the ovulatory cycle of the chicken and what are the timing events that controls it. Is there any wild species similar

Follicular phase, left ovary, photoperiod responsive ovulation 26 hours, 21 day incubation; birds

How similar is deer reproduction to our model species in seasonality, cycle and gestation length and anatomy

22 day cycle, seasonally polyesrus

Define large cat reproduction in cycle and gestation length? Is there any similarity to our model species in anatomy and physiology

Induced ovulators, gestation 104-110 days

Define non-human primate reproduction, in cycle and gestation length? Is there any similarity to our model species in anatomy physiology?

non seasonal, menstrual, 1-2 days of heat, gestation length 225 days