Short answer

Explain the difference between endocrine and exocrine functions of the testes:

The testes have both endocrine and exocrine functions. Endocrine secretes hormones such as testosterone from Leydig cells and inhibin from Sertoli cells, which regulate spermatogenesis and male reproductive function. Exocrine, produce sperm in the seminiferous tubules, where Sertoli cells support developing germ cells and mature spermatozoa are released into the tubules leading to the rete testis.

How is Testicular temperature regulated?

4 main processes, The tunica dartos provide sustained long-term contraction or relaxation, when the testes are cold they will be raised and stay close to the body and when hot they will be relaxed away from the body. The cremaster muscle gives short-term control by raising or lowering the testes in response to temperature or stress (fight-or-flight), such as being in a fight or jumping the fence. The pampiniform plexus cools incoming arterial blood through counter-current heat exchange with venous blood cooling the arterial blood as it enters the testes. The scrotum also aids cooling by being attached to neural sweat glands and triggering panting or sweating when the testes get hot.

What are the accessory sex glands and their functions?

The seminal vesicles, prostate gland, and bulbourethral glands. The seminal vesicles produce most of the seminal fluid, which provides energy and helps sperm survive and move through the reproductive tract. The prostate gland adds fluid to semen that nourishes and protects sperm. The bulbourethral glands secrete a lubricating fluid (gel fraction in boars) that helps cleanse and protect the urethra before ejaculation.

Explain the difference between vascular and fibroelastic penis:

The human and stallion vascular penis enlarges greatly due to blood filling erectile tissue, while the bull, boar, ram and buck fibroelastic penis straightens with little change in size due to the sigmoid flexure.

Describe the pathway of sperm through the male reproductive system

The testes produce both sperm and testosterone and are kept at an optimal temperature through thermoregulation. Sperm are formed in the seminiferous tubules through a process called spermatogenesis. They then move into the rete testis, which collects sperm, and pass through the efferent ductules to the epididymis, where they mature and are stored.

During ejaculation, sperm travel through the vas deferens to the ejaculatory ducts and then enter the urethra. Along the way, they mix with fluids from the seminal vesicles, prostate gland, and bulbourethral glands, which nourish, protect, and help transport the sperm. The urethra carries the semen out of the body through the penis, which delivers it into the female reproductive tract.

Explain the configuration of the ovary:

The ovary is covered by the tunica albuginea and consists of the cortex, medulla, and hilus. The cortex is the region where follicles and corpus luteum (CL) develop, ovulate happens here, while the medulla contains loose connective tissue, blood vessels, and nerves, and the hilus is the attachment area where vessels and nerves enter the ovary. 

Explain the differences of reproductive anatomy in the mare and other species:

 In mares, the cortex is located internally and ovulation occurs only at the ovulation fossa. In other species, the cortex is the outer layer and the medulla is internal, with follicles and CLs found in the cortex. 

What are the structures found on the ovary and what are their functions?

Follicles contain and develop the oocyte before ovulation. After ovulation, the follicle becomes the corpus hemorrhagicum (CH), a temporary structure that forms the corpus luteum. The corpus luteum (CL) produces progesterone to maintain pregnancy and prevent ovulation. If pregnancy does not occur, it regresses into the corpus albicans (CA), a scar tissue remnant.

What are the stages of follicle development and what are the parts of a tertiary follicle?

Follicles develop through primordial, primary, secondary, tertiary, and dominant stages. The primordial follicle is the most immature with a single layer of squamous cells. The primary follicle has a growing oocyte surrounded by cuboidal granulosa cells. The secondary follicle has multiple layers of granulosa cells but no antrum. The tertiary follicle has granulosa and theca layers with an early antrum and produces estrogen. The dominant follicle has a fully formed antrum, cumulus and mural granulosa cells, and theca cells, and is ready for ovulation.

What are the components of the female reproductive tract and their functions?

The female reproductive tract includes the ovary, which produces oocytes and hormones; the oviduct, which transports the oocyte and is the site of fertilization; the uterine horns, which support embryo development in many species; the uterine body, which connects the horns and supports pregnancy; the cervix, which acts as a protective barrier and regulates passage into the uterus; the vagina, which serves as the copulatory organ and birth canal; the vestibule, which is the shared passage for the reproductive and urinary tracts; and the vulva, which is the external opening that protects the tract. The broad ligament supports the reproductive tract and is divided into the mesovarium (supports the ovary), mesosalpinx (supports the oviduct), and mesometrium (supports the uterus).

What are the layers of the female tubular system and their functions?

The female tubular system has four layers: the mucosa, which is the inner lining involved in secretion and absorption; the submucosa, which is connective tissue that provides support and blood supply; the muscularis, which is smooth muscle that contracts to move sperm and oocytes; and the serosa, which is the outer protective layer.

What are the sections of the oviduct and the role of each section?

The oviduct is divided into the infundibulum, ampulla, and isthmus. The infundibulum collects the ovulated oocyte from the ovary using fimbriae. The ampulla is the main site of fertilization. The isthmus transports the embryo to the uterus and regulates movement between the oviduct and uterus.

What are the layers, functions, and classifications of the uterus?

The uterus has three layers: the perimetrium, an outer protective serosal layer; the myometrium, a smooth muscle layer responsible for uterine contractions; and the endometrium, the inner lining involved in implantation, embryo nourishment, and secretion. The uterus supports embryo and fetal development, provides uterine secretions, and contracts during reproduction and parturition. It is classified as bicornuate with highly developed uterine horns in the sow, bitch, and queen; bicornuate with poorly developed uterine horns in the mare and cow; duplex with two cervices in rabbits and marsupials; and simplex with no uterine horns in humans.

What are the species differences in the cervix?

The cervix acts as a physical and chemical barrier and a site for sperm storage and function. In the cow and ewe, the cervix has annular rings; in the sow, it has interdigitating pads; and in the mare, it has longitudinal folds.

What are the parts and functions of the vagina and external genitalia?

The vagina is the copulatory organ and birth canal, the vestibule is a shared passage for the reproductive and urinary tracts, the vulva is the external opening that protects the reproductive tract, and the clitoris is a sensory erectile structure involved in sexual response.

What are the hormone-producing cells of the anterior pituitary and their hypothalamic controls?

Gonadotrophs secrete FSH and LH in response to GnRH. Lactotrophs secrete prolactin and are inhibited by dopamine (PIH). Somatotrophs secrete growth hormone (GH) in response to GHRH and are inhibited by somatostatin (GHIH). Thyrotrophs secrete TSH in response to TRH, and adrenotrophs secrete ACTH in response to CRH.

How is GnRH secretion controlled by the hypothalamus?

GnRH secretion is controlled by the hypothalamus through a pulsatile release system involving tonic and surge centers. The tonic center regulates regular, baseline GnRH release, while the surge center triggers a large pre-ovulatory LH surge in response to high estradiol levels. GnRH secretion is also influenced by negative and positive feedback from sex steroids such as estrogen and progesterone.

Give an example of each secretion:

Endocrine: In cattle, insulin acts on the liver and muscle through the bloodstream to regulate blood glucose. Paracrine: In cows, prostaglandin F2α acts on nearby ovarian and uterine cells to cause luteolysis. Autocrine: In livestock immune cells, cytokines act back on the same cell that released them to enhance immune response.Intracrine: In the mare’s ovary, steroid hormones act within the same follicular cells where they are produced. Lactocrine: In piglets, growth factors in colostrum act on the intestines to support development and immunity. Pherocrine: In pigs, boar pheromones act on sows to stimulate estrus behavior.

List each secretion:

Endocrine- Acts on distant target organs via the bloodstream

Paracrine- Acts on nearby cells

Autocrine- Acts on the same cell that produced it

Intracrine-Acts inside the same cell that produced it

Lactocrine- Acts on the nursing offspring via milk

Pherocrine- Acts on other individuals of the same species through environmental chemical signals

What are the three chemical classifications of hormones and their basic characteristics with examples?

Hormones are classified as protein/peptide, fatty acid, or steroid. Protein/peptide hormones are amino acid chains such as LH, FSH, and oxytocin. Fatty acid hormones are derived from arachidonic acid, such as prostaglandins. Steroid hormones are derived from a cholesterol backbone, such as testosterone, progesterone, and estrogen (estradiol).

Describe the roles of the hypothalamus, anterior pituitary, and posterior pituitary in hormone regulation:

The hypothalamus produces releasing and inhibiting hormones (such as GnRH, GHRH, TRH, and CRH) that control the pituitary gland. The anterior pituitary responds to these signals by producing and secreting hormones including FSH, LH, prolactin, TSH, ACTH, and growth hormone (GH). The posterior pituitary does not make hormones; instead, it stores and releases hormones produced by the hypothalamus through the infundibular stalk.