Reproductive System Flashcards
What is each teste surrounded by?
Tunica vaginalis
Where does the sperm pass?
Passes from tubules to the epididymis
What is the scrotum made from?
Rugose and contains smooth muscle
What divides the two sides of the scrotum?
Midline raphne made from septum
Where do the ovaries lie?
Lateral pelvic wall
Where does the ovary ovulate into?
Peritoneal cavity where the ovum is picked up by the fimbriated end of the uterine tube
What is the uterus held in place?
Fascial thickenings and uterine ligaments
What is the function of gonads?
Production of “seed” cells
What are gonadal hormones involved in?
Gamete production
Supporting conception
Pregnancy
Lactation
Affect bone, muscle and blood vessels
What process are used to produce eggs and sperm?
Oogenesis
Spermatogenesis
What are the hormones associated with the hypothalamic-pituitary-gonadal axis?
Hypothalamic signalling hormone
Gonadotropin-releasing hormone
Pituitary hormones
Luteinising hormone
Follicle stimulating hormone
What do the hormones from the hypothalamic-pituitary-gonadal axis target in males and females?
Ovaries to produce progesterone and oestradiol
Testis to produce testosterone from Leydig cells
What do the ovaries secrete?
Oestrogens and progestins
What does the multi-tiered endocrine axis feedback allow?
Good control of hormone secretion
What are the main hypothalamic areas involved in ovarian control?
Preoptic nucleus
Supraoptic nucleus
Describe the secretion of GnRH from the hypothalamus?
Produced as prohormone
Then modified to an active from
It is then secreted into the hypophyseal portal system
What kind of release is GnRH?
Pulsatile- requires low energy
Where is GnRH delivered to?
Delivered via the hypophyseal portal circulation to anterior pituitary gonadotrobes
After the GnRH has reached the gonadotrobes, what do they secrete?
Follicle stimulating hormone
Luteinising hormone
What is the function of a ovarian follicle?
Production of eggs and to release hormones
What are the four stages of development of ovaries?
Primordial
Primary
Secondary
Tertiary
Graafian follicles
What are the endocrine functions of the ovaries?
By using theca and granulosa cells, produce and secrete oestradiol
What is the function of the hormone oestradiol?
Regulating menstrual cycle
Development of breasts
Widening of hips
Layering of fat
Development and maintenance of mammary glands, uterus and vagina
Where are theca cells found?
Superficial layer of follice
What is the function of theca cells in ovaries?
Once LH binds to its receptor;
Convert cholesterol into pregnenolone
Then produce androstenedione and testosterone
Where are the granulosa cells?
Deep compared to theca cells
What receptors does granulosa cells have?
LH and FSH
What is the function of granulosa cells?
Convert cholesterol into pregnenolone and activate aromatase
What is the function of aromatase?
Produce oestrogens
Facilitates formation of oestradiol
When does oogenesis begin?
Begins in foetal stage of females
When do woman reach their max oocyte number?
Around 20 weeks since gestation
What are the three main oestrogens?
Oestradiol
Oestrone
Oestriol
What is the effect of oestrogens on bone?
Increase growth
What is the effect of oestrogens on endocrine?
increase progesterone responses
What is the function of progesterone?
Regulate the condition of the inner lining (endometrium) of the uterus
What is the effect of oestrogens on the liver?
Increase clotting factors
Increase steroid-binding proteins
Increase HDL
Decrease total cholesterol and LDL
What is the function of oestrogens on the reproductive organs?
Increase of;
Uterine growth
Vaginal and fallopian tube growth
Breast growth
Cervical mucus secretion
LH receptors on granulosa cells
What causes a positive feedback loop between the ovaries and the anterior pituitary gonadotrophs?
Activins
What causes a negative feedback loop between the ovaries and the hypothalamus or anterior pituitary gonadotrophs?
Oestrogens
Progestins
Inhibins
When do oestrogens and progestins do not provide a negative feedback loop?
When ovulation needs to occur
Describe the process of oestrogens and progestins switching to a positive feedback loop
Increased upregulation of receptors when oestrogen levels are increased
Results in LH and FSH surge
Where are progestins produced?
Theca and granulose
What is the effect of progestin on breast tissue?
Increase in lobular development and endometrial secretions
Decrease in milk production and endometrial growth
Mucosal secretions become thicker
What is the effect of progestin on temperature?
Increase in internal temperature
What is progestin secretion regulated by?
Oestrogen secretion
What are the two components of the menstrual cycle?
Ovarian cycle and endometrial cycle
In the 28 day ovule cycle, when does ovulation occur?
Day 14
What are the two stages of the ovarian cycle?
Follicular phase and luteal phase
What happens in the follicular phase?
Development of follicles and secondary oocyte
What happens in the luteal phase?
The corpus luteum is formed through the granulosum and theca cells
Corpus luteum synthesizes and secretes oestrogen and progesterone which is needed for implantation and maintenance of any fertilised oocytes
Corpus luteum regresses in 10-12 days
What are the different stages of the endometrial cycle?
Menstrual phase
Proliferation phase
Secretion phase
What happens in the menstruation phase?
Endometrial lining is replaced through;
Vasoconstriction of spiral arteries
Local ischaemic injury
Inflammatory cell infiltration
What happens in the proliferative phase?
Endometrial growth mediated by increased oestrogens
Blood vessel and gland growth occur
What happens in secretory phase?
Maturation of endometrium due to decreasing oestrogens
Mucus glands more fully develop
Glands and blood vessels increase surface area
What is lactation?
Milk production and secretion
What develops breast tissue?
Female gonadal hormones
Oestrogens
Progestins
hCG from foetus
Prolactin
What is milk production mediated by?
Prolactin
What mediates the release of milk?
Oxytocin
What are the two types of cells in the testis?
Leydig cells
Sertoli cells
What is the function of Leydig cells?
Produce testosterone
What happens when testosterone enters the Sertoli cell?
Stimulates FSH causing the seminiferous tubules to produce sperm
Produces aromatase which then produces Oestradiol which regulates protein synthesis in the Leydig cell
What are the different stages of spermatogenesis and how many chromosomes do they have in each stage?
Spermatogonia
Primary spermatocytes- 1x46
Secondary spermatocytes- 2x23
Spermatids
Spermatozoa
What regulates spermatogenesis?
Testosterone
What effect does testosterone have on bone?
Increase growth of bone and connective tissue
What effect does testosterone have on muscle?
Increase growth of muscle and connective tissue
What effect does testosterone have on the reproductive organs?
Increase growth and development of testes, prostate, seminal vesicles and penis
Increase growth of facial, axillary and pubic hair
Increase growth of larynx
Increase spermatogenesis
What effect does testosterone have on skin?
Increase of sebaceous gland size and secretions
Describe the negative feedback loop from the testes to either the anterior pituitary gonadotropes or the hypothalamus?
Testosterone negative to the APG and hypothalamus
Inhibin negative to the APG
