Male reproductive lecture content (exam #4) Flashcards
What the components of the male repro system?
Testes, excretory ducts, penis, and accessory sex glands
What are the structure of the testis?
-tunica albuginea testis
-Septuli tetis
-Seminiferous tubules
-Mediastinum testis
-Rete testis
Tunica albuginea testis
-dense connective tissue capsule covering
-serous membrane (visercal vaginal tunic) adhered to the surface
Septuli testis
-loose connective tissue trabeculae subdividing testis into lobules
-leydig cells
Leydig cells (testis)
-interstitial polyhedral cells
-eosinophilic cytoplasm. Large spherical nuclei, distinct nucleoli
-secretes testosterone, insulin-like protein 3, and oxytocin
Seminiferous tubules
-sertoli cells
-spermatogonia
-primary spermatocytes
-secondary spermatocytes
-spermatids
-mediatstinum testis
-rete testis
Sertoli cells (seminiferous tubules)
-columnar cells, pale staining nucleus, distinct nucleolus
-extend through full thickness of epithelial surface
-cytoplasmic process surround adjacent spermatogenic cells
-secretion of estrogens
-formation of blood testis barrier
Blood-testis barrier
isolates haploid germ cells (secondary spermatocytes, spermatids, and sperm) from blood stream and immune cells. Prevents immune response against sperm ad infertility.
Mediastium testis
-connective tissue cord extending through long axis of testis
-connected with tunica albuginea testis via septuli testis
-atypical and inconspicuous in horses
-contains rete testis
Rete testis
-complex series of interconnecting channels with the mediastinum
-receives fluid from the seminiferous tubules
-connects to the head of the epididymis
What are the developmental cell stages in spermatogenesis?
-spermatogonia
-primary spermatocytes
-secondary spermatocytes
-Spermatids
Spermatogonia (spermatogenesis)
-large, spherical, basally-located cells with variable morphology
-undergo mitosis to form continuous supply of germ cells
Primary spermatocytes (spermatogenesis)
-second layer of cells adjacent to spermatogonia
-undergo DNA replication (2n and 4d), then division into 2 secondary spermatocytes (2n and 2d)
Secondary spermatocytes (spermatogenesis)
-undergo meiotic division into 4 spermatids (1n and 1d)
-smaller than primary spermatocytes
-difficult to identify (pass through 2nd meiotic phase and form spermatids quickly)
Spermatids (spermatogensis)
-small round to tadpole shaped cells
-thick layer of cells nearest lumen of seminiferous tubule
What are the functions of the epididymis
-storage and maturation of sperm
-decapacitation factor added to the sperm surface
-removal of degenerating sperm
Structure of the epididymis
head body tail
Epididymis
-crescent-shaped, elongated structure lying along surface of the testicle
-Regionally divided into head body and tail
-covered with collagenous connective tissue
-connective tissue separate from inner tunica albuginea epididymis segregates organ into lobules
efferent ductules of epididymis
-Begins as 6-20 straight vessels that become coiled and form 6-10 coiled masses
-thin walled
-lined with alternating clamps of tail (ciliated) and short (microvilli) pseudostratified epithelial cells
-thin collagenous lamina propria with circular smooth muscle
Ductus epidiymis (body, tail)
lined with pseudostratified ciliated columnar epithelium
-decreased coiling of ducts as tail region is approached
The route developing sperm take as they move through the male duct system from seminiferous tubule to urethra
The sperm travels from the testes to the epididymis, then to the vas deferens, then to the prostate, and ultimately to the urethra
Seminiferous tubules –> Rete testis –> Vasa efferentia –> Epididymis –> Vas deferens –> Ejaculatory duct –>Urethra –>
Regional anatomy of the male penis
Root (radix)
Body
Glans
Root (Radix)
crura and penile bulb
Body (penis)
corpus cavernosum penis, corpus spongiosum penis
Glans (penis)
corpus spongiosum penis
Know the basics of ejaculation and how they are controlled by the nervous system
For coitus to occur, the cavernous erectile tissue of the penis must fill with blood. This is accomplished through stimulation from the parasympathetic nervous system. Blood flow is increased to the erectile tissue spaces, while simultaneously decreasing venous return. The erectile spaces gradually fill with blood, and the penis increases in length and girth. The degree of expansion is dependent on species. The body of the penis is the segment spanning the distance between the glans and root. Once the penis is intromitted (placing one organ or organ segment inside another) into the vagina, the sympathetic nervous system stimulates accessory sex glands to secrete into the urethra. Next, rhythmic contractions of skeletal muscle covering the cavernous erectile tissue compartment housing the urethra cause a
transduction of these wave-like contractions into the underlying blood-filled spaces and onto the surface of the urethra. This results in propelling the ejaculate through the urethra, out of the penis and into the vagina.
What are the accessor sex glands present in males
-prostate
-vesicular glands
-ampulla gland
-bulbourethral gland
Prostate gland
-Body and disseminate part-species dependent
-surroundns urethra (partially or wholly, depending on species)
-compound tubular gland
-watery secretions
Vesicular glands
-paired organs
-contributing to ejaculate
-white gelatinous secretion provides energy source
Ampulla gland
-present in species dependent
-branched tubular structure with sparse glandular tissue
-simple columnar epithelium
-thick tunica muscularis
-white serous secretion
Bulbourethral gland
-presence is species dependent
-paired organs
-connective tissue capsule containing smooth muscle in most species
-trabeculae radiate from capsure to form lobules
-simple columnar eptithelium
-clear mucus-like secretion
Know the structure and function of the urethra.
The male urethra can be divided into three sections: the prostatic urethra (the uppermost segment within the prostate), the membranous urethra (the segment within the urethral sphincter), and the spongy urethra (the lowermost and longest section within the penis)
Overall, the function of the male urethra is to allow passage of urine and semen. The urethra connects the distal portions of the urinary system, such as the urinary bladder, to the external environment and allows for urine excretion from the body.
The penile urethra is enclosed by the corpus spongiosum and lined with stratified columnar and pseudostratified epithelium with stratified squamous epithelium distally. The entire posterior urethra is lined with a submucosa and a series of muscular sphincters.
Understand the influence of testosterone and estrogen on the male reproductive system.
Leydig cells –> secrets testosterone (testicle development, development of accessory sex glands, secondary sex characteristics, maintains spermatogenesis), Insulin-like protein 3 (stimulates testicular descent, marker for evaluating fertility),
Testosterone –> Testosterone is an androgen that are produced in the testes. It is responsible for the development of male accessory sex organs, muscular growth, and secondary sexual characters. It regulates spermatogenesis and libido in males. They also regulate bone mass, fat distribution, muscle mass, and strength.
Estrogen (estradiol) –> However, estradiol, the predominant form of estrogen, also plays a critical role in male sexual function. Estradiol in men is essential for modulating libido, erectile function, and spermatogenesis.
