Animal Reproductive Systems and Physiology

Comprehensive practice questions covering male and female reproductive anatomy, hormones, puberty, and the estrous cycle in domestic animals.

How is puberty defined in animals?

The age or time at which the reproductive organs first become functional and reproduction may occur.

In females, what physical event characterizes the beginning of puberty?

The beginning of ovulation, which is the release of an egg cell from a follicle.

What external factors can delay the onset of puberty in animals like cattle and horses?

Poor nutrition, disease, exposure to stress, and extremes of temperature.

What are the definitions for gestation and parturition?

Gestation is the period of development from fertilization until birth; parturition is the act of birth.

What is the typical age range for the onset of puberty in horses and swine?

Horses: $10–24\text{ months}$; Swine: $5–8\text{ months}$.

What is the role of the epididymis in the male reproductive system?

It is where sperm continue to mature and are stored until ejaculation.

Which tube transports sperm from the epididymis to the urethra during ejaculation?

The ductus deferens.

What are the four accessory sex glands in males, and which one is the only gland present in dogs?

The ampullae, seminal vesicles, prostate, and bulbourethral glands; dogs have only the prostate gland.

What are the specific functions of fructose and prostaglandins found in seminal vesicle secretions?

Fructose provides energy for the sperm, and prostaglandins stimulate female uterine contractions to help move semen.

What is the function of the thin alkaline fluid secreted by the prostate gland?

It balances the acidity of the remaining urine in the male system and the acidity of the vagina.

What are the roles of FSH and LH in the male reproductive system?

They act on the testes to stimulate spermatogenesis and the production of testosterone.

What is the difference between musculocavernous and fibroelastic penis types regarding erection speed?

Musculocavernous (stallion, dog) are slow to become erect; fibroelastic (bull, ram, boar) can become erect rapidly.

What are the three portions of ejaculate in domestic species?

1. Sperm-free portion, 2. Sperm-rich portion, 3. Sperm-poor portion.

What are the three sex hormones produced by the ovaries?

Estrogen, progesterone, and relaxin.

What are the dimensions of the ovaries in a bitch and a cow?

Bitch: $2\text{ cm} \times 1.5\text{ cm}$; Cow: $3\text{ cm} \times 2\text{ cm}$.

What is the function of the fimbria at the end of the uterine tubes?

They are fingerlike projections that help "catch" the ova as they are released from the ovary during ovulation.

Where does fertilization normally occur in the female reproductive tract?

In the uterine tubes (also called oviducts).

What is the placenta?

An attachment formed by the endometrium (the innermost layer of the uterus) to the fetus to provide developmental support.

What is the biological difference between oogenesis and spermatogenesis regarding the timing of gamete production?

Oogenesis is completed before or shortly after birth (females are born with a full supply), while spermatogenesis in males occurs all the time after puberty.

What is follicular atresia?

The process by which most oocytes degenerate and die instead of being ovulated.

Which animals are classified as induced ovulators?

Cats (queens), rabbits, and ferrets.

What structure develops in the follicle after ovulation to produce progesterone?

The corpus luteum.

Define Monestrous, Polyestrous, and Seasonal Polyestrous animals.

Monestrous: one cycle per year; Polyestrous: frequent cycles throughout the year; Seasonal Polyestrous: periodic cycles only during certain times of the year.

What occurs during the proestrus phase of the estrous cycle?

The reproductive tract prepares for breeding: follicular growth occurs, estrogen increases, and the vaginal lining thickens or cornifies.

What defines the anestrus phase?

A period characterized by an inactive, functionless reproductive tract and ovaries.

What are the functions of the hormone oxytocin?

It causes smooth muscles to contract in the uterus for parturition and in the mammary glands to stimulate lactation.

Which hormone is essential for the maintenance of pregnancy?

Progesterone.

What is the function of relaxin late in pregnancy?

It is responsible for relaxing the pelvic ligaments and cervix to allow for parturition.