chapter 17 - The human life cycle

reproductive organs:

• production and transport of gametes

• penis

• vagina

• uterus

• breasts

• hormone production

production and transport of gametes:

sex cells; sperm and ova

penis:

deliver sperm to vagina

vagina:

transports menstrual fluid to exterior and birth canal

uterus:

fertilizes the egg

breasts:

nourishment in form of breastmilk

hormone production:

masculine and feminine features

why meiosis is called reduction division:

results in halving number of chromosomes in daughter cells

meiosis takes place here in the human body:

• testes of males during sperm production

• ovaries during oocyte production

sperm contain:

23 chromosomes

eggs contain:

23 chromosomes

testes located outside of the human body:

sperm production requires lower temperature than the body’s core temperature

where sperm is produced:

testes; specifically seminiferous tubules

function of enzymes: acrosome

needed to penetrate the oocyte

sperm:

• head - penetrate oocyte

• middle piece - provide energy for movement of tail

• tail - flagellum

internal accessory organs: male

• epididymides

• vas deferens

• seminal vesicles

• prostate

• bulbourethral glands

function of epididymides:

ducts where sperm mature and some are stored

function of Vas Deferens:

transport and store sperm

function of seminal vesicles:

contribute nutrients and fluid to semen

zygote =

first cell of a new human being

function of Prostate:

contributes basic fluid to semen

function of bulbourethral glands:

produce mucoid fluid that neutralizes urine

external genitals: male

penis

ovaries =

primary sex organs

ovaries produce the _____ and the hormones estrogen and progesterone

female sex hormones (Ova)

Oogenesis =

production of eggs in females by the process of meiosis and maturation

why older women may be more likely to produce children with chromosome defects?

oocytes are present at birth and age with the woman

internal accessory organs: female

• uterine tubes

• uterus

• cervix

• vagina

function of uterine tubes:

transport ovum; location of fertilization

function of uterus:

houses developing fetus

function of cervix:

contains opening to uterus

function of vagina:

receives penis during sex; serves as birth canal and exit for menstrual flow

cervical and ovarian cancer:

• papillomavirus causes cervical cancer

• ovarian is the “silent” cancer; enlargement of abdomen caused by an accumulation of fluid

function of the menstrual cycle:

prepare female body for potential pregnancy each month; last about 28 days but can be shorter

importance of self-examination for cancer:

allows people to become familiar with their bodies and detect change sooner

contraception =

pregnancy prevention

causes of infertility:

• males: low sperm count and/or large proportion of abnormal sperm count

• females: body weight

artificial insemination:

placement of donated sperm into vagina

intrauterine insemination:

fertility drugs used to stimulate ovaries and donors sperm is placed in the uterus rather than vagina

In Vitro fertilization:

eggs are fertilized in a laboratory; viable embryos are placed into the uterus

Intracytoplasmic sperm injection:

single sperm is injected into the egg

• usually when men have severe infertility problems

cause of genital warts:

human papillomavirus (HPV)

cause of genital herpes:

herpes simplex virus

cause of hepatitis:

contaminated food/water, blood-borne, sexually transmitted, etc.

cause of chlamydia:

chlamydia trachomatis

cause of gonorrhea:

neisseria gonorrheae

cause of syphilis:

treponema pallidum

effects of aging: reproductive

• sex hormone levels decline

• menopause (age 44-55)

• diminished testosterone production (age 50)

• erectile dysfunction

activities of the sex hormones affect the internal environment: homeostasis

• activate oil glands

• stimulates fat deposition

• influences growth of skeletal muscle

• influences cardiovascular health

• promotes growth if skeletal muscle

benefits and risks of replacing hormone production:

• + relief of menopause symptoms and increased bone density

• - increased rates of cancer, heart disease, stroke, and blood clots

combined hormonal method of contraception is available through:

• pills

• patches

• injections