Diagrams & Processes (Reproduction) Flashcards
(39 cards)
- What is the function of the scrotum and the cremaster and dartos muscles?
To regulate the temperature of the testes. They contract in cold temp to bring testes closer to body and wrinkle scrotum which reduces heat loss and relax in hot temp to lower testes, smooth out scrotum to allow cooling.
- Describe the structure of the testes.
Paired oval glands in the scrotum, 5cm by 2.5cm diameter. Serous membrane=Tunica vaginalis
covers tough white connective tissue layer of tunica albuginea. Septa of tunica albuginea form 200300 lobules within testis. Seminiferous tubules (1-3) fill each lobule.
- Where in the testes are sperm produced?
Seminiferous tubules
What are the functions of the Sertoli and Leydig cells and where in the testes are they located?
Sertoli cells- form blood-testis barrier, support and protect developing spermatogenic cells, release sperm into lumen of seminiferous tubule, produce fluid for sperm transport, secrete inhibin when sperm numbers sufficient for efficient reproduction. Located inside seminiferous tubules.
Leydig cells
secrete testosterone. Located between adjacent seminiferous tubules.
How does anaphase I of meiosis differed from anaphase of mitosis and anaphase II of meiosis?
Paired chromatids remain attached at centromere, ie. Chromosome pairs are separated rather than
the chromatids of the individual chromosomes.
What is the significance of meiosis I?
Reduction division, as each resulting cell contains the haploid number of chromosomes because it contains only one member of each pair of homologous chromosomes present in the starting cell.
Describe the process of spermatogenesis, including the final stage, spermiogenesis.
Spermatogenesis takes 65-75 days. Spermatogonia (2n) undergo mitosis and some spermatogonia stay near basement membrane while others squeeze through blood –testis barrier, undergo developmental changes and become primary spermatocytes (2n). Meiosis I begins and secondary spermatocytes (n) are formed. Meiosis II forms 4 spermatids (n). Cytoplasmic bridges link the 4 spermatids. In the final stage, spermiogenesis, spermatids are freed from their cytoplasmic bridges
and elongate to form sperm cells.
What are the functions of the sperm cell acrosome and middle piece?
Acrosome-enzymes contained within cap like vesicle help sperm penetrate a secondary oocyte to complete fertilisation
Describe the hormonal control of spermatogenesis and testosterone secretion.
LH stimulates Leydig cells to release testosterone. FSH and testosterone act synergistically to cause spermatogenesis. FSH acts on the Sertoli cells to begin meiosis and FSH and testosterone stimulate Sertoli cell secretion of androgen-binding protein (ABP) which maintains high levels of testosterone
necessary for final stages of spermatogenesis in seminiferous tubules.
What are the functions of testosterone?
Pre-natal testosterone causes development of male reproductive organs and ducts, later causes development of male sexual characteristics, sexual function and stimulation of anabolism.
List the components of the duct system of the male reproductive system in order, from testes to urethra.
Seminiferous tubules, straight tubules, rete testis, efferent ducts, ductus epididymis, ductus (vas) deferens, ampulla of ductus deferens, ejaculatory duct, prostatic urethra.
Name the structures in the spermatic cord.
Ductus (vas) deferens, testicular artery, veins from testes, nerves, lymph vessels, cremaster muscle.
Describe the entry of the spermatic cord through the abdominal wall.
Passes through the inguinal canal which is an oblique passage way about 4-5cm long, in the anterior abdominal wall.
What are the three subdivisions of the male urethra?
Prostatic, membranous and spongy urethra
Describe the locations and functions of the accessory sex glands.
Seminal vesicles- paired convoluted pouch-like structures about 5cm long, posterior to base of
urinary bladder, joins ampulla of ductus deferens before forming ejaculatory duct. Secrete alkaline
Which accessory sex gland contributes the majority of seminal fluid?
Seminal vesicles
Which tissue masses form the erectile tissue in the penis and how do they become rigid during sexual arousal?
Corpora cavernosa (paired) and corpus spongiosum. Parasympathetic fibres cause dilation of smooth muscle in arterioles of erectile tissue which allows increased blood filling and closes off veins draining the erectile tissue.
Which tissue mass keeps the urethra open during ejaculation?
Corpus spongiosum
Explain the physiological processes involved in ejaculation.
Sympathetic reflex; peristaltic contractions of epididymis, ductus deferens, seminal vesicles, ejaculatory ducts and prostate propel semen into spongy urethra prior to ejaculation, smooth muscle sphincter at base of bladder closes, musculature of penis contracts.
What are the functions of the ovaries?
Production of secondary oocytes, that develop into mature ova after fertilisation, production of the hormones, estrogen, progesterone, inhibin and relaxin
How are they held in place in the pelvic cavity?
Broad ligament of the uterus and mesovarium enclose ovaries and attaches them to pelvic wall; ovarian ligament anchors ovaries to uterus; suspensory ligament attaches ovaries laterally to the pelvic wall.
Which structures in the ovary serve an endocrine function, and which hormones do they secrete?
Follicles produce estrogen. Corpus luteum secretes progesterone, estrogen, relaxin and inhibin
How does the age of a primary oocyte in a female compare with the age of a primary spermatocyte in a male?
Primary oocytes are produced during foetal development while primary spermatocytes are produced after puberty in males.
