I) Testosterone: main androgen (male sex hormone)

A) Intro to Testosterone:

-produced in response to luteinizing hormone (LH)

from anterior pituitary gland

-steroid hormone produced by interstitial cells in

testes

1) meat more tender

2) lack of sex drive

3) lowered aggression (particularly sexual

aggression)

***Human castration: 17th-18th C many boys had

testes removed to halt puberty and retain soprano

voices “Castrati”

-effects of lack of testosterone documented in

livestock animals that have been castrated (testes

removed)

2 - male hormones/ female systemMay 7, 2012 5:08 PM

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B) Functions of Testosterone

1) stimulates spermatogenesis (in seminiferous tubules)

-facial & body hair

2) stimulates development of secondary sexual

characteristics: signals of sexual maturity

-enlargement & lengthening of larynx

-increased production in body oils & pheromones

-increased musculature: both skeletal & smooth (ie,

CASTRATO,

BBC

Documentary

Part 1 of 6

CASTRATO,

BBC

Documentary

Part 2 of 6

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-increased musculature: both skeletal & smooth (ie,

male dermis = 40% thicker than female)

-change in bone structure & proportion

3) maturation of penis & testes during puberty

(primary sexual characteristics: gamete production &

delivery)

4) behavioral effects: sex drive

5) increased

muscular

development:

anabolic steroids are

testosterone-like

drugs

C) Regulation of Testosterone Production

-at ~age 10, hypothalamus matures & releases

gonadotropin releasing hormone (GnRH) which targets

anterior pituitary (this occurs in both males & females)

1) follicle stimulating hormone (FSH): target = testes

-stimulates development & maintenance of

seminiferous tubules

-in response, anterior pituitary releases 2 hormones

with different target tissues

Minute 12-17ish on Natl Geogr vid

Testosterone

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2) luteinizing hormone (LH): target = interstitial cells

in testes

-causes interstitial cells to make and release

testosterone

-testosterone can then act on its target tissues (ex:

seminiferous tubules)

-recall: hypothalamus = centre of homeostasis. It

monitors testosterone levels in blood.

-therefore, anterior pituitary reduces FSH and LH

release

-therefore, testes produces less testosterone & sperm

cells

-If testosterone is too high, hypothalamus reduces

GnRH release

-negative feedback loop:

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Question: how can excessive use of steroid hormones

(drugs) cause infertility & shrivelled testes in males?

Explain (potential test bonus question)

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II) Female Reproductive Tract

-designed to produce ova, receive penis & semen,

house & nourish fetus, produce milk

Natl Geogr video 18:25-20:30

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A) Main structures

-size & shape of almonds, close to wall of pelvic

cavity, held in place with loose connective tissue and

pelvic ligaments

-outside = single epithelial layer

-inside = loose connective tissue & ova (scattered in

varying developmental stages)

1) ovary (2) – produce ova & hormones (estrogen &

progesterone)

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-release 1 ovum during “ovulation”

1) follicles: contain maturing ova, mature in response

to FSH from anterior pituitary

2) corpus luteum: remnants of follicle left in ovary that

become a temporary gland in response to LH from

anterior pituitary

-produces estrogen & progesterone

-if no pregnancy, it disintegrates & becomes a scar

called corpus albicans

2) oviduct (2) (aka fallopian tubes): receive ovum

following ovulation

-not directly

connected to ovary:

fingerlike

“fimbriae” catch

ovum as it bursts

from ovary wall

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ovum as it bursts

from ovary wall

-lined with beating cilia to sweep ovum down

length. Also performs peristalsis

-location of fertilization: ovum begins to disintegrate

upon leaving ovary. By end of oviduct, ovum no

longer capable of becoming fertilized by sperm so

fertilization must occur before this

-fist-sized, inverted-pear in shape

-thick walls of smooth muscle

-many capillaries for lots of transport to and from

fetus

-inner face is lined with membranous tissue:

endometrium

3) uterus: receives ovum or zygote (fertilized ovum),

and nourishes fetus during pregnancy

LookWho_s Ta...

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fetus

-glandular tissue for secreting a nutrient medium

to nourish zygote

-during ovulation, mucus becomes watery so sperm

can pass

-usually plugged with mucus to prevent entry of

bacteria but also = barrier for sperm

-allows endometrial layer to be shed during

menstruation

-keeps developing fetus inside uterus through

pregnancy, but during birth, dilates to ~10 cm

(diameter of baby’s head) to allow exit

4) cervix: narrow opening at base of uterus

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-detected by Pap Smear test

-common site for cancer, often caused by HPV,

transferred from head of penis

5) vagina: receives penis during sexual intercourse,

birth canal for exit of baby (& endometrium during

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-stretch elastic muscular tube which leads from

cervix to outside body

birth canal for exit of baby (& endometrium during

menstruation)

-in front of vagina, short (~2 cm) tissue with same

nerve endings as head of penis

-usually necessary to stimulate for female orgasm

6) clitoris: organ of sexual stimulation, analogous to

male penis

Ovulation

ovulation (2)

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