Reproductive System Flashcards
What is the pouch of serous membrane surrounding each testes?
Tunica vaginalis
Where are testes kept to keep them cool?
Scrotum
What is the purpose of the seminiferous tubules in testes?
Site of germination, maturation and transport of sperm cells to epididymis
What muscle is found in the skin of the scrotum?
Dartos smooth muscle
What defines the midline of the penis and scrotum?
Raphe
What divides the scrotum?
Septum
Where are ovaries situated?
In the peritoneal cavity
What characteristic feature of the fallopian tube allows ovum to enter during ovulation?
The end of the tube is fimbriated
What is the fundus of the uterus?
The end of the uterus that extends into the peritoneal cavity
What is the purpose of thickening of fascia on pelvic wall?
Supportive uterine ligaments
What do gonads produce?
Seed cells/gametes
What are the layers of the female gonads from inside out?
Granulosa, theca interna, theca externa
What is the structure of a sperm?
Consists of a head, a neck containing mitochondria and a tail
What do female gonads produce?
Oocytes by oogenisis
What do male gonads produce?
Sperm by spermatogenesis
What processes are gonadal hormones involved in?
Gamete production
Conception
Pregnancy
Lactation
Describe the common stages of the hypothalamic pituitary gonadal axis
Hypothalamus releases gonadotropin-releasing hormone GnRH
Pituitary glands then release hormones luteinising hormone LH and the follicle stimulating hormone LSH
What response is brought about in the ovaries by the hypothalamic pituitary-gonadal axis?
Progesterone and oestradiol released
What is the function of progesterone?
Regulates condition of inner lining of uterus, needed for implantation and maintenance of fertilised oocytes
Function of oestradiol?
Matures and maintains reproductive system
increased levels during menstruation allow maturation and release of egg and thickening of uterine wall to allow egg to implant
What response is brought about in the male gonads by the hypothalamic pituitary-gonadal axis?
testosterone produced by Leydig cells
What is the hypophyseal portal system?
System of blood vessels in microcirculation at the base of the brain that connects the anterior pituitary gland with the hypothalamus
What secretes GnRH?
Preoptic nucleus neurons which target gonadotropes
Supraoptic nucleus neurons
Where is GnRH secreted?
Into hypophyseal portal system and delivered to anterior pituitary gonadotropes
Consequences of GnRH release being pulsatile?
- requires less energy
- does not desensitise tissue receptors
- stress influences secretion
What gonadotropins are secreted by the gonadotrobes in the pituitary gland?
FSH and LH which target the gonads
What is the endocrine function of the ovaries?
Theca and granulosa cells work cooperatively to secrete oestradiol
What do oocytes contain?
Follicles in verious stages of development (primordial, primary, secondary, teriary, Grafiaan)
What are theca cells?
The superficial layer of the oocyte follicle containing LH receptors
What are the functions of theca cells?
convert cholesterol to pregenolone
produce androstenedione and testosterone
What forms the cavity inside female gonads that don’t enclose the oocyte?
Antrum
What morphological change occurs in granulosa cells during follicle development?
Layers increase in size from primary to secondary follicle development
Function of granulosa cells?
Have LH and FSH receptor
convert cholesterol into pregnenolone and activate aromatase
When does oogenesis occur?
In fetal stage
Outline process of oogenesis?
Primordial germ cells (oogonia) increase in number
Many mature into oocytes
At 20 weeks gestation oocyte numbers reach max
Oocyte numbers decline until exhausted
What are the 3 main oestrogens?
Oestradiol
oestrone
oestriol
Where is progesterone produced?
Theca and granulosa cells
What are the 2 divisions of the menstrual cycle?
Ovarian cycle which happens first
Endometrial cycle
What is the first phase of the ovarian cycle and what occurs during it?
Follicular phase: development of mature Graafian follicle and secondary oocyte
What separates the follicular and the luteal phase?
Ovulation
What is the second phase of the ovarian cycle that occurs after ovulation and what occurs during it?
Luteal phase: corpus luteum actions such as synthesis and secretion of oestrogen and progesterone
Function of corpus luteum
Secretes hormones such as oestrogen and progesterone but degenerates in 10-12 days if there is no fertilisation
What are the 3 phases of the endometrial cycle in order?
Proliferative phase
Secretory phase
Menstruation
What occurs in the proliferative phase of the endometrial cycle?
Increase in oestrogens mediating endometrial growth
Blood vessels and glands grow
Ovulation marks end of phase
What occurs in the secretory phase of the endometrial cycle?
Decrease in oestrogens results in maturation of endometrium
Mucus glands develop
Glands and blood vessels increase in surface area
What occurs during menstruation of endometrial cycle?
If no conception, endometrial lining is replaced
Vasoconstriction of spiral arteries
Local ishaemic injury
Inflammatory cell infiltration
What occurs in the mammary glands?
Lactation: milk production and secretion
Breast tissue prepared during puberty by female gonadal hormones
Further development in pregnancy by oestrogens, progestins, hCG from fetus, and prolactin
What regulates milk production?
Prolactin
What mediates milk “let-down”
Oxytocin
What is contained in the testis?
Leydig cells
blood vessels
seminiferous tubules (produces sperm and houses Sertoli cells)
Where does testicular endocrine functions occur?
Leydig and Steroli cells
Explain spermatogenesis
Spermatogonium develops into primary spermatocytes, then secondary spermatocytes, then spermatids and then spermatozoa
What regulates spermatogenesis?
Testosterone
Explain what happens when LH binds to its receptor on the Leydig cell?
Causes testosterone production
Testosterone enters Sertoli cell
FSH stimulation activates aromatase which forms oestradiol
What is oestradiol’s function in Leydig cells?
Regulates protein synthesis in the nucleus
Testosterone effect on bone?
Growth of bone and connective tissue
Effect of testosterone on muscle?
Growth of muscle and connective tissue
Effect of testosterone on reproductive organs?
Growth and development of testes, protstate, seminal vesicles and penis
Growth of facial, axillary and pubic hair
Growth of larynx
Spermatogenesis
Effect of testosterone on skin?
Increase in sebaceous gland size and secretions
What do Sertoli cells do?
facilitate the progression of germ cells to spermatozoa
Effect of progestins on breast tissue?
Increased lobular development
decreased milk production
Effect of progestins on reproductive organs?
Decreased endometrial growth
Increased endometrial secretions
Effect of progestins on tempertature?
Increased internal temperature
Effect of oestrogen on bone?
Increased growth by osteoblasts
Effect of ostrogen on endocrine system?
Increased progesterone responses
Effect of oestrogen on the liver?
Increased clotting factors
Increased steroid binding proteins
Effect of oestrogen on the reproductive organs?
Increased uterine growth
Increased vaginal and fallopian tube growth
increased breast growth
Increased cervical mucus secretion
Increased LH receptors on granulosa cells
Explain what causes the shift from negative to positive feedback during oestrogen and progestin secretion?
Upregulation of receptors when oestrogen levels are increased. Results in LH and FSH surge
What differences are there between testosterone and oestrogen secretion?
Testosterone has one primary hormone
