Reproductive Physiology 1

Anatomy of the male and female reproductive systems

Formation of gametes

Gametogenesis comparison 1
  Spermatogenesis Oögenesis
spermatogonia
types Ad, Ap, and B
oögonia
two mitotic divisions  
4 primary spermatocytes primary oöcyte
first meiotic division  
  8 secondary spermatocytes secondary oöcyte
first polar body
second meiotic division  
  16 spermatids mature ovum
3 second polar bodies
16 spermatozoa

Sertoli cells

spermiation

Female hormonal system

hypothalamic releasing hormone

gonadotropin releasing hormone [GnRH] 2
[also known as luteinizing hormone releasing hormone (LHRH)]

anterior pituitary hormones 3

follicle-stimulating hormone [FSH]

luteinizing hormone [LH]

ovarian hormones

steroids

estrogens [mostly β-estradiol]

progesterone

peptides

GnRH

relaxin

inhibin

inhibin A:  αβA

inhibin B:  αβB

activin

βAβA

βAβB

βBβB

follistatin

the monthly ovarian cycle

role of gonadotropic hormones FSH and LH

follicle function

control

theca cells produce androgens [LH]

granulosa cells convert androgens into estrogens [FSH]

negative feedback from estrogens

inhibin

development

primordial follicle

primary follicle

vesicular follicles

secondary follicles

Graafian follicles

follicular atresia

ovulation triggered by LH surge

halts estrogen secretion

blocks granulosa cell release of oöcyte maturation inhibiting factor

triggers production of prostaglandins

promotes luteinization

corpus luteum function maintained by LH

production of progesterone and estrogens

inhibin not secreted by luteal cells

the monthly endometrial cycle

structure of the uterine wall

endometrium

stratum basale

stratum spongiosum

stratum compactum

myometrium

epimetrium

stages

proliferative phase

secretory phase

menstruation

Stages of female sexuality

infancy and childhood

puberty

menarche

menopause

climacteric

Questions for thought
1.   What effect would low levels of circulating FSH have on the number of sperm produced? Explain.
2.   What changes would you expect to see in the ovarian and uterine cycles if luteinizing hormone were not produced?
3.   Explain why FSH levels rise and remain high during menopause.
4.   Describe the main differences in gamete production between males and females.
5.   Contraceptive pills that contain estradiol or a combination of estradiol and progesterone are given in programmed doses during the ovarian cycle to prevent follicle maturation and ovulation. Explain why this happens.
6.   Describe the hormonal events associated with the ovarian cycle and their effects on the uterus.


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