Reproductive Physiology Flashcards
Describe the structure of the cortex of an ovary.
Connective tissue containing ovarian follicles
What does the medulla of the ovary contain?
Connective tissue with blood vessels
What is a primordial follicle?
Primary oocytes arrested in first meiotic division
Surrounded in one layer of granulosa cells
What is a primary follicle?
An oocytes surrounded by zona and cuboidal granulosa cells.
What is a secondary follicle?
Increased oocyte diameter and multiple layre of granulosa cells
Resumption of first meiotic division
What is a graffian follicle?
Tertiary follicle
Follicular fluid between the cells which coalesce to form antrum
Completion of first meiotic division to form secondary oocyte and start of second meiotic division
What is the corpus albicans?
Degenerated corpus luteum
What is the function of the cervix?
Connects vagina to uterus
Produces mucus that changes in consistency during the menstral cycle.
Dilates during child brith
When are the primordial follicles arrested?
First meiotic division
From where are FSH and LH released from?
Anterior pituitary
What hormones does the ovary release?
Oestrogen
Progesterone
Inhibin
AMH
What secondary sex characteristics do estrogens control?
Breast development
Pattern of fat distribution
What secondary sex characteristics are governed by androgens?
Pubic and axillary hair
Sex drive
What are androgens?
Hormones that contribute to growth and reproduction
Prevent bone loss and bone disease
Where are androgens released from?
Primarily from the adrenal glands and ovaries
What hormone causes the endometrium to grow and proliferate after menstration?
Oestrogen from developing follicles
What causes several follicles in the ovary to mature?
FSH
What decreases follicle sensitivity to FSH?
AMH
This prevents the additional recruitment of additional primary follicles
What is the role of oestrogen in the early follicular phase?
Exerts a negative feedback effect on the pituitary FSH and LH secretion which prevents the develop of additional follicles.
Oestrogen is produced from the follicles.
When does ovarian oestrogen peak?
At the end of the follicular phase
When does ovulation occur in relation to the LH surge?
Around 16-24hrs after LH peaks
What hormones does the corpus luteum produce in the luteal phase?
Progesterone and oestrogen
Describe the levels of LH and FSH during the luteal phase.
The combination of oestrogen and progesterone exerts a negative feedback on the hypothalamus and anterior pituitary.
LH and FSH production remains shut down throughout most of the luteal phase.
What are the actions of progesterone in the luteal phase in preparation for possible pregnancy?
Endometrium grows and proliferates
Also causes cervical mucus to thicken
What happens if pregnancy does not occur?
The corpus luteum undergoes apoptosis to become the corpus albicans which is inactive.
As the luteal cells degenerate, oestrogen and progesterone production decreases.
This removes the negative feedback signal to the pituitary and LH and FSH increase in production.
Around 2 days after the corpus luteum ceases to function, the endometrium begins to shed its surface layre and menstration begins
What three types of cells exist in the seminiferous tubules?
Spermatogonia. Sertoli. Interstitial (leydig)
what are the functions of Sertoli cells?
Support sperm
Produce inhibin
What does the basal lamina of the seminiferous tubule allow to enter?
Testosterone
What are the 3 compartments of the seminiferous tubule?
- Tubule lumen
- Basal compartment
- Interstitial fluid
Was is the average time from production of sperm to ejaculation?
64 days
From what cell is testosterone produced?
Leydig cell
When are leydig cells active?
In the fetus when testosterone is needed to direct development of male characteristics.
After birth the cells become inactive until puberty when they resume testosterone production.
From what cell is inhibin released?
Sertoli
What is the blood-testes barrier?
Adjacent Sertoli cells in tubule are linked to each other by tight junctions that form an additional barrier between the lumen of the tubule and the interstitial fluid outside the tubule. These tight junctions are called the blood-testes barrier. They form 3 compartments.
How long is the sperm cycle?
3 months
What controls spermatogenesis?
Testosterone
What do testosterone and inhibin inhibit?
GnRH secretion by hypothalamus
LH and FSH by pituitary
Secretions from what glands contribute to semen?
Bulbourethral
Seminal vesicles
Prostate
What are the two distinct phases of spermatogenesis?
- Spermatogenesis
2. Spermiogenesis
What happens during spermatogenesis?
Clonal expansion and maturation through mitotic and meiotic process. Produce a population of cells destined to become sperm
What is spermiogenesis?
Differentiation into mature sperm cells. Process begins at puberty. Maturation of spermatids into functional sperm cells.
Where does 99% of the volume of semen come from?
Accessory glands
What is the function of semen?
Provides a liquid medium for delivering sperm
Describe the contribution of the bulbourethral gland to semen.
Contribute mucous for lubrication and buffers to neutralise the usually acidic environment of the vagina
Describe the contribution of the seminal vesicles to semen
Contribute prostaglandins that influence sperm motility and transport
What pretesticulal factors can affect spermatogenesis?
Problems with hormonal control of sperm production. Such as excessive weight loss, intracranial tumours, cysts, prolactinoma, medications, genetic
What testicular factors affect spermatogenesis?
Problem at site of production for example: surgery, STI, mumps, testicular trauma or torsion, radiotherapy or chemotherapy
What environment/ lifestyle factors affect spermatogenesis?
Maternal/paternal smoking
Persistent organic pollutants
Sedentary position of father
Accumulation of body fat of parents
At what point of the female cycle does raised temperature indicate?
Ovulation
