Porth's Essentials of Pathophysiology, 4e

1022

Genitourinary and Reproductive Function

U N I T 1 1

Preantral follicle

Primary follicle

Preovulatory follicle

Antral follicle

Primordial follicle

Theca externa Theca interna Granulosa cells

Atretic follicle

Stroma

Hilum

A

Corpus albicans

Oocyte Antrium

Germinal epithelium

B

Ovulation

Early corpus luteum

Mature corpus luteum

FIGURE 40-7. (A) Cross-section of preovulatory follicle. (B) Schematic diagram of an ovary, showing the sequence of events in the origin, growth, and rupture of an ovarian follicle and the formation and retrogression of a corpus luteum.The atretic follicles are those that show signs of degeneration and death.

lipoproteins. They produce an increase in high-density lipoproteins (HDLs), a slight reduction in low-density lipoproteins (LDLs), and a reduction in cholesterol lev- els. Estrogens also increase plasma triglyceride levels, and they enhance the coagulability of blood by increasing the circulating levels of plasminogen and factors II, VII, IX, and X. Estrogens, which have a chemical structure similar to adrenal cortical hormones, can also cause sodium and

water retention by the kidney. Most women retain sodium and water and gain weight just before menstruation. The actions of estrogens are summarized in Table 40-1. Although the ovaries are the major source of estrogen, the biosynthesis of estrogens that occurs in adipose tis- sue may be a significant source of the hormone. There is evidence that a certain minimum body weight and fat content are necessary for menarche to occur and for the

TABLE 40-1  Actions of Estrogens General Function

Specific Actions

Growth and development  Reproductive organs

Stimulate development of vagina, uterus, and fallopian tubes in utero and of secondary sex characteristics during puberty

 Skeleton

Accelerate growth of long bones and closure of epiphyses at puberty

Reproductive processes  Ovulation

Promote growth of ovarian follicles

 Fertilization

Alter the cervical secretions to favor survival and transport of sperm Promote motility of sperm within the fallopian tubes by decreasing mucus viscosity Promote development of endometrial lining in the event of pregnancy

 Implantation

 Vagina  Cervix  Breasts

Proliferate and cornify vaginal mucosa

Increase mucus consistency

Stimulate stromal development and ductal growth

General metabolic effects  Bone resorption

Decrease rate of bone resorption

 Plasma proteins

Increase production of thyroid and other binding globulins Increase high-density and slightly decrease low-density lipoproteins

 Lipoproteins