The Reproductive System

Human Physiology – From Cells to Systems | 9e Lauralee Sherwood Chapter 20

23

Gametes contain how many chromosomes?

Gametogenesis

accomplished by meiosis

• results in genetically unique sperm and ova

Testes

develop from the gonadal ridge located in the rear of abdominal cavity

• one drops into each pocket of the scrotal sac

Spermatogenesis

yields an abundance of highly specialized, mobile sperm

• several degrees Celsius less than normal body (core) temperature

LH; FSH

control testosterone secretion and spermatogenesis

• anterior pituitary

Testosterone

roles of testosterone or FSH in spermatogenesis:
germ cell mitosis and meiosis

FSH

roles of testosterone or FSH in spermatogenesis:
spermatid remodeling

GnRH

activity increases at puberty

Semen

mixture of accessory sex gland secretions

• make up only a small percentage of the total ejaculated fluid

Male sex act

Male sex act or female sex act?
erection and ejaculation

erection

Penish vasocongestion accomplishes what?

Erection reflex

spinal reflex triggered by stimulation of sensitive mechanoreceptors

Erectile dysfunction

pattern of failing to achieve or maintain an erection suitable for sexual intercourse

Ejaculation

includes emission and expulsion

Emission

semen is delivered into the urethra

Expulsion

semen is expelled through the urethra

primary oocyte

After puberty, one _____ _____ reaches maturity and is ovulated about once a month until menopause ensures.

Orgasm

feeling of release and complete gratification

• completed the sexual response cycle

Resolution

feeling of deep relaxation

• completed sexual response cycle

excitement, plateau, orgasm, & resolution

What are the four phases of the sexual cycle?

menopause

Female reproductive potential ceases during middle age at what?

intermittent

Release of ova is _________.

Gametogenesis

• formation of primary oocytes & primordial follicles

• formation of secondary oocytes

• formation of mature ovum

• comparison of steps in oogenesis & spermatogenesis

Ovarian cycle

Consists of alternating follicular and luteal phases

28 days

The average ovarian cycle lasts how many days?

maturing follicles

The follicular phase is characterized by development of _____ ______.

Luteal phase

characterized by the presence of a corpus luteum

• formation of corpus luteum

• degeneration of the corpus luteum

• corpus luteum of pregnancy

ovarian

Cyclic uterine changes are caused by hormonal changes during the _______ cycle.

• menstrual phase

• influences of estrogen & progesterone

• proliferative phase

• secretory, or progestational, phase

cervical mucus

Fluctuating estrogen and progesterone levels produce cyclical changes in what?

Follicular phase

mucus secreted by the cervix becomes abundant, clear, and thin

ovulation

After what?
mucus becomes thick and sticky

menopause

unique to females

45; 55

Menopause occurs between the ages of _____ and ______.

Oviduct

site of fertilization

• ovum transport to here

• sperm transport to here

• fertilization

Blastocyst implants

in the endometrium by means of its trophoblastic enzymes

• descent of the morula to the uterus

Placenta

organ of exchange between maternal and fetal blood

• functions: pass oxygen, nutrients, and antibodies from mothers blood to baby

Human chorionic gonadotropin (hCG)

stimulates the secretion of testosterone by the developing testes in XY embryos

• maintains the corpus luteum of pregnancy

Estrogen

stimulates growth and maintenance of the entire female reproductive tract

• thins the cervical mucus to permit sperm penetration

• promotes development of secondary sexual characteristics

• stimulates granulosa cell proliferation, which leads to follicle maturation

estrogen

What is essential for egg maturation and release?

Progesterone

• prepares a suitable environment for nourishment of a developing embryo and then fetus

• Suppresses uterine contractions to provide a quiet environment for the fetus

• causes a thick mucus plug to form in the cervical canal

• helps prepare mammary glands for lactation

Relaxin

• softens cervix in preparation for cervical dilation at parturition

• loosens connective tissue between pelvic bones in preparation for parturition

Placental PTHrp

increases maternal plasma Ca2+ level for use in calcifying fetal bones

• if necessary, promotes localized dissolution of maternal bones, mobilizing their Ca2+ stores for use by the developing fetus

late gestation

Changes during what stage prepare for parturition?

Parturition

• accomplished by a positive feedback cycle

  • stages of labor

  • uterine involution

breast feeding

What is advantageous to both the infant and the mother?

Lactation

Stimulation via suckling