Animal Sciences Midterm 2

Progesterone ALWAYS creates a negative feedback loop to decrease what hormones?

GnRH and FSH/LH

Female gonad and gamete

Ovary and Oocyte

Estrogen creates a positive feedback loop when there is low progesterone but a negative loop when progesterone is high. True or false?

True-Positive loop is designed to increase GnRH and LH/FSH

What hormones are produced by the female gonad?

Estrogen and Progesterone

What are the male gonads and gametes?

Testis and sperm

What are the functions of gonads? (There's two)

Produce hormones, produce gametes

Can you measure all the hormones produced by HPG axis in the blood?

No

Sertoli cells are located in the ____ compartment while the Leydig cells are located in the ____ compartment. (In the testis)

Tubular and interstitial

1. Spermatogonia
2. Primary/secondary spermatocyte
3. Spermatid
4. Spermatozoa

1. Undergoes Mitosis
2. Undergoes meiosis
3. Undergoes spermiogenesis
4. Undergoes spermiation

When a cow fails to become pregnant, the ____ produces the hormone PGF2 that causes ____.

Uterus and regression of the Corpus Luteum

What process causes sperm to be unable to dock to the oviduct?

Sperm capacitation

Types of placentas
1.Diffuse
2. Zonary
3. Discoid
4. Cotyledonary

1. Horse/pig
2. Carnivores
3. Primates/rodents
4. Ruminants

Fetal ____ triggers parturition due to limited space and oxygen

Stress

Two main characteristics of the penis is ruminants

Presence of the sigmoid flexure and the relaxation of the retractor muscle to allow erection

Where does the female oocyte grow?

In the follicle/ovarian follicle

The remaining cells of the ____ differentiates into the ____ that produces progesterone after ovulation

Follicle and Corpus Luteum

Where is the testes is sperm produced?

Seminiferous tubules

Where is sperm matured?

Epididymis

What do Sertoli cells do?

Support spermatogenis (Also FSH dependent)

What do Leydig cells do?

Support testosterone production (LH dependent)

Hormone that starts parturition

Fetal cortisol

Period of time where an animal or woman can't get pregnant

Puerperium

Three main functions of the epididymis

Sperm transport, sperm storage, sperm maturation

Three parts of temperature regulation for the testes

Scrotal skin, Pampiniform plexus, cremaster muscle

Main functions of the accessory sex glands

Nourish/activate spermatozoa, clear urethral tract, produce secretions to help sperm, forms plug to help sperm stay in female tract-(This is only in rodents)

Two characteristics of the penis in ruminants and swine

Sigmoid flexure and retractor muscle

The presence of a polar body indicates what is mature?

Oocyte

2 polar bodies indicate what has happened?

Fertilization

Where is milk produced?

Alveolus

If there is no pregnancy, what happens to the CL?

Functional/structural regression. CL will stop secreting progesterone (functional) and the cells will die (Structural)

What is the order of steps in a follicular wave?

Recruitment, selection, dominance, ovulation/atresia

In cattle and horses the embryo prevents PGF2a secretion during maternal recognition of pregnancy. True or false?

True

The uterus will secrete ____ to cause regression of the ____

PGF2a, CL

What is menopause?

Decline in the amount of reproductive hormones, usually in older women. Caused by a limited # of oocytes from birth

Why does one spermatogonium produce four sperm cells but one oogonium produce only one oocyte?

4 sperm cells are produced due to equal division during meiosis. During oogenesis, there is unequal division, with only one functional cell (future oocyte) taking most of the cell organelles while a polar body ( non-functional) is small with essentially no organelles.

Length of time of meiosis for oogonium to be completed?

Fetal development until fertilization.

Three types of estrous cycles

1. Polyestrous-Women, rodents, cows, pigs
2. Seasonally polyestrous-Horses and sheep
3. Monoestrous-Dogs

4 phases of the estrous cycle in order, beginning at ovulation

1. Estrus/ovulation-Attracts males, accepts breeding, estrogen dominant
2. Metestrus-Doesn't accept breeding, CL developed
3. Diestrus-Doesn't accept breeding, mature CL
4. Proestrus-Attracts males, doesn't accept breeding

What is the cause of Luteolysis?

Uterus produces PGF2a to cause regression of CL

What are the main hormones in the estrous cycle and their functions?

LH-Stimulates late follicle growth/CL function, promotes ovulation,
FSH-Stimulates follicle growth
Progesterone-Preparation of uterus, maintain pregnancy, negative feedback loop to decrease LH levels
Estradiol-Negative feedback loop to decrease FSH, can create positive feedback loop to raise LH levels

What are the phases of sperm transport?

Rapid transport and Sustained transport

Can the stage of the estrus cycle affect sperm transport?

Yes

Where does fertilization occur?

Ampulla (Fertilized embryo takes 3-5 days to go to the uterus)

Acrosome reaction

Enzymes in Acrosome digest Zone Pellucida to allow entrance of sperm nucleus

Syngamy

Fusion of female and male pronucleus