ANS 150 Reproduction + Genetics Exam 2

NCSU - Dr. Flowers

Management systems for most animals are based upon

The female reproductive cycle

The female reproduction cycle

Estrus, Gestation, Birth, Lactation, Weaning, Rebreeding

The primary function of males

To provide spermatozoa for breeding

What does the Ovary contain?

Thousands of growing follicles

What does each follicle contain?

An ovum or “egg”

The ovary receives a rich supply of

Both blood vessels and nerves

What to follicles grow in response to?

Hormones called gonadotropins

What is it called when a follicle dies?

Becoming atretic

A follicle will either…

• Die (become atretic)

• Ovulate and release their egg

What is follicle death also called?

Atresia

What does CL stand for?

Corpus Luteum

What do CL’s come from?

The tissue that remains after a follicle has ovulated

What does a CL produce?

A number of hormones associated with pregnancy

What is a CL’s primary product?

Progesterone

What does CA stand for?

Corpus Albicans

What is a CA?

It is scar tissue left behind after a CL dies or regresses

True or False: CA’s are vascular and functional tissue.

FALSE.

• CA’s are avascular and non-functional tissue.

What shape is the oviduct?

Funnel shaped

What is the specialized end of the oviduct near the ovary called?

The fimbria

What does the fimbria do?

The fimbria picks up ovulated eggs

What is the ANTERIOR end of the oviduct called?

Ampulla

What is the POSTERIOR end of the oviduct called?

Isthmus

What takes place in the oviduct in most animals?

Fertilization and early embryonic development

Glandular inner lining that is surrounded by two layers of muscle

Uterus

What kind of layers does the uterus have?

Longitudinal and circular layers

What is the uterus responsibe for?

The maintenance of pregnancy

What does the uterus release?

The hormone that regresses luteal tissue.

Thick, muscular organ

Cervix

What is the purpose of the cervix?

To isolate the uterus from the external environment during pregnancy

True or false:

The cervix is the site or semen deposition in all animals.

FALSE.

The cervix is the site of semen deposition in SOME - but not ALL - animals.

What is the vagina?

It is a part of the birth canal

What does the vagina do?

It helps protect the uterus from bacterial invasion

What is the site of semen deposition in most animals?

The vagina

What is the vulva?

External female genitalia

True or false:

The vulva is the outer portion of the vagina.

TRUE.

What is the vulva involved with?

The recognition of receptivity and with the production of female pheromones.

What is a testicle?

A series of tubules (seminiferous tubules)

What does the testicle produce?

Spermatozoa and hormones

What hormones does the testicle produce?

Testosterone, androgens, and others

What is the epididymis?

The continuation of tubule in the testicle

What enters the epididymis?

Immature sperm

What is the epididymis specialized for?

The maturation and storage of spermatozoa

What happens to sperm during their passage through the epididymis?

They become mature

Muscular tube with a small diameter

Vas deferens

What does the vas deferens do?

It is the passage for sperm from the epididymis to the urethra during ejaculation.

What are the secondary sex glands?

Seminal vesicles, prostate, and bulbourethral glands

What do the secondary sex glands do?

Produce and secrete most of the liquid portion of semen

True or False:

The composition of each secondary sex gland is fairly specialized.

TRUE.

The male reproductive organ

Penis

What is the penis specialized to do?

Deposit semen in the female reproductive tract

What is the central canal of the penis called?

Urethra

What is the urethra a common exit for

The reproductive and urinary systems

Specialized pouch in which the penis remains when not in use

Sheath

In some animals, the lining of the sheath is involved in what?

Male pheromone production

What does it mean by semen is a “suspension”?

The sperm cells are in seminal fluids

How do sperm leave the epididymis

Very concentrated

Where does sperm travel through?

The vas deferens to the urethra

Which secondary sex gland secretes the largest amount of fluids into the urethra that mixes with sperm?

Seminal vesicles

What are the 3 groups of female endocrinology based on functions?

1. Gonadotropins

2. Sex steroids/prostaglandins

3. Mammotropins

What do gonadotropins do?

Stimulate ovary

What do sex steroids/prostaglandins do?

They have direct control of reproductive state

What do mammotrophins do?

Involved with lactation

What are the gonadotropins hormones?

• Luteinizing hormone (LH)

• Follicle stimulating hormone (FSH)

What is LH and FSH produced by?

Pituitary gland

What does LH do?

• Stimulates final growth of follicles

• Causes ovulation

• Stimulates CL

What does FSH do?

Stimulates all stages of follicle growth, especially early periods

What are the sex steroids/prostaglandins hormones?

• Progesterone

• Estrogen

• Prostaglandin

What is progesterone produced by?

CL and the placenta (in some animals)

What does progesterone do?

• Responsible for maintenance of pregnancy

• Inhibits gonadotropin secretion

What is estrogen (estradiol 17beta) produced by?

Growing follicles, placenta, and embryos

What effect does estrogen have on gonadotropins?

It has both positive and negative effects

What does estrogen do?

• Stimulates pre-ovulatory surge of gonadotropins

• Prepares female for breeding and parturition (giving birth)

• Responsible for female mating behaviors

Where is Prostaglandin F2alpha produced?

Primarily produced by the uterus in the reproductive system

What does prostaglandin F2alpha do?

• Responsible for luteal regression

• Causes uterine contractions at birth

What are the mammotropins hormones?

• Prolactin

• Oxytocin

Where is prolactin produced?

Pituitary gland

What does prolactin do?

Stimulates production of milk

What is oxytocin produced by?

The uterus and hypothalamus

What does oxytocin do?

Stimulates milk excretion and uterine contractions

What are the stages of the reproductive cycle?

Puberty, Estrous cycles, Pregnancy (gestation), Lactation, Post-partum period (rebreeding)

What do reproductive cycles involve?

Interactions between the ovary, uterus, mammary gland, and brain.

• They all communicate with one another via hormones and nerves.

The age at which an animal is capable of adult repoductive function.

Puberty

Adult reproductive function for females includes…

• Estrus

• Production of fertile eggs

• Maintenance of pregnancy

Adult reproduction for males includes…

• Libido

• Mating

• Production of fertile sperm

What is the last function to mature during puberty?

The brain and the production of gonadotropins (specifically LH)

What are the ovaries and testes capable of before puberty is reached?

Gamete and hormone production

Repeatable sequence of events that results in female becoming sexually receptive

Estrous cycle

What does the estrous cycle begin with?

Estrue (period of sexual receptivity)

At estrus, what is high/low?

Estrogen is high

Progesterone is low

What does high estrogen cause?

Preovulatory surge of gonadotropins

What causes ovulation?

LH surge

What happens during estrous?

• Follicles release eggs

• Estrogen decreases

• CL’s form

• Progesterone is produced from CL

During the estrous cycle, what is decreased and why?

Gonadotropin secretion is decreased because of progesterone

During the estrous cycle, how many days are progesterone and CL maintained for?

12 to 16 days

During the estrous cycle, what is released from a non-pregnant uterus?

Prostaglandin

During the estrous cycle, what is destroyed?

CL’s

During the estrous cycle, what decreases, and what increases?

Progesterone decreases

LH and FSH increase

During the estrous cycle, what grows?

Follicles

At a certain level of ___, females exhibit ____ and then ____.

At a certain level of Estrogens, females exhibit Estrus and then Ovulate.

After ovulation, what occurs?

Fertilization and embryonic development occurs