1. 6.6 Hormones, homeostasis and reproduction
Hormones are used when signals need to be widely distributed.

2. Insulin and glucagon are secreted by β and α cells of the pancreas respectively to control blood glucose concentration.

3. Application: Causes and treatment of Type I and Type II diabetes.

4. Thyroxin is secreted by the thyroid gland to regulate the metabolic rate and help control body temperature.
Q: Why do we iodize our salt?

5. Leptin is secreted by cells in adipose tissue and acts on the hypothalamus of the brain to inhibit appetite.
Application: Testing of leptin on patients with clinical obesity and reasons for the failure to control the disease.

6. Melatonin is secreted by the pineal gland to control circadian rhythms.
Q: Define circadian rhythm.
Q: Explain how levels of melatonin are related to the sleep-wake cycle.
Application: Causes of jet lag and use of melatonin to alleviate it.

7. Q: List three secondary sex characteristics of males.
A gene on the Y chromosome causes embryonic gonads to develop as testes and secrete testosterone.
Q: What combinations of chromosomes are connected to males and females?
Testosterone causes pre-natal development of male genitalia and both sperm production and development of male secondary sexual characteristics during puberty.
Q: About when could you determine if a baby was a male? Justify your answer.
Q: List three secondary sex characteristics of males.

8. Skill: Annotate diagrams of the male and female reproductive system to show names of structures and their functions.
Testis – produce sperm and testosterone
Scrotum – keep testis below body temperature
Epididymis – store sperm until ejaculation
Sperm duct – transfer sperm during ejaculation
Seminal vesicle and prostate gland – secrete fluids added to sperm to make semen; neutralizes acidic conditions inside vagina
Urethra – transfer semen during ejaculation and urine during urination
Penis – penetrate vagina for ejaculation of semen near the cervix

9. Q: List three secondary sex characteristics of females.
Estrogen and progesterone cause pre-natal development of female reproductive organs and female secondary sexual characteristics during puberty.
Q: List three secondary sex characteristics of females.

10. Skill: Annotate diagrams of the male and female reproductive system to show names of structures and their functions.
Ovary – produce eggs, estrogen, and progesterone
Oviduct – collect eggs at ovulation, provide a site for fertilization then move the embryo to uterus
Uterus – provides the needs of the embryo and then fetus during pregnancy
Cervix – protect fetus during pregnancy and then dilate to provide a birth canal
Vagina – stimulate penis to cause ejaculation and provide a birth canal
Vulva – protect internal parts of female reproductive system

11. Q: Explain the functions of each of the four hormones listed above.
The menstrual cycle is controlled by negative and positive feedback mechanisms involving ovarian and pituitary hormones. The roles of FSH, LH, estrogen and progesterone in the menstrual cycle are expected.
Q: Explain the functions of each of the four hormones listed above.
FSH
stimulates development of the follicle, stimulates secretion of estrogen
Estrogen
stimulates repair and thickening of the uterine wall LH
stimulates completion of meiosis in developing egg, development of follicle into corpus luteum
Progesterone
promotes thickening and maintenance of endometrium, inhibits FSH and LH secretion

12. What is going on in the uterus at these times?
Uterine walls are “empty”
Endometrium is building up,
and up and up…
Menstruation
(endometrium is shed)

13. What is going on in the ovaries at these times?
Follicle turns into corpus luteum
Ovulation
Follicle matures
Corpus luteum disappears
Follicle appears
What hormone does the follicle make?
Estrogen
What hormone does the corpus luteum make?
Progesterone

14. At what time is a female most fertile? Why?
Right before and after ovulation a female is most fertile. It is at this time that she has released a “fresh” egg, and afterwards the egg dies.
Therefore, right before and after menstruation is when she is least fertile.
Most fertile

17. Male Female Pituitary Gland Vas Deferens Progesterone to the… to the…
Sperm cells start here and travel from…
Which stands for
Contains a gland called the
function
Which makes a 2 hormones called…
to the…
Pituitary Gland
Which stands for
function
These 2 hormones stimulate the ovary to make a structure that will eventually release an egg; this structure is called a.
to the…
makes a hormone called
Vas Deferens
function
to the…
The egg is eventually released; this is called
Which causes the uterus to build the
function
to the…
The leftover follicle changes into a structure called the
function
Which causes the uterus to maintain the
to the…
It makes a hormone called
Progesterone
function
to the…
If the egg is fertilized, then the endometrium becomes the
If the egg is not fertilized, then there is a decrease in the level of the hormone
function
Ejaculation happens, and sperm first enters the female’s
and then travels through the female’s cervix, uterus, and fallopian tube to find an egg
Which will produce the hormone
This causes the endometrium to die; it will be pushed out by contractions of the
and provide nutrients to the embryo for about 9 months until the uterus contracts, pushing the fetus out through the
and will exit through the vagina in a process called

18. Male Female Brain Testicle FSH Pituitary Gland LH Epididymis Follicle
Sperm cells start here and travel from…
Spermatogenesis happens here
Which stands for
Contains a gland called the
Testicle
Which makes a 2 hormones called…
FSH
Follicle stimulating hormone
function
to the…
Pituitary Gland
Which stands for LH
Luteinizing hormone
Sperm matures here and is stored until ejaculation
Epididymis
function
These 2 hormones stimulate the ovary to make a structure that will eventually release an egg; this structure is called a.
to the…
Sperm travels through this tube during ejacultion
Follicle
makes a hormone called
Estrogen
Vas Deferens
function
to the…
The egg is eventually released; this is called
Which causes the uterus to build the
Adds fructose (a sugar for sperm food) and mucus (to lubricate sperm)
Seminal vesicle
function
Ovulation
Endometrium
to the…
Adds fluids that neutralize the acids in the vagina, to help the sperm survive
Prostate
The leftover follicle changes into a structure called the
function
Which causes the uterus to maintain the
to the…
It makes a hormone called
A duct shared between urine and sperm
Corpus Luteum
Progesterone
Urethra
function
to the…
If the egg is fertilized, then the endometrium becomes the
If the egg is not fertilized, then there is a decrease in the level of the hormone
Enters the vagina, delivering the sperm and semen
Penis
function
Placenta
Progesterone
Ejaculation happens, and sperm first enters the female’s
and then travels through the female’s cervix, uterus, and fallopian tube to find an egg
This causes the endometrium to die; it will be pushed out by contractions of the
Which will produce the hormone
Progesterone
Uterus
Vagina
and provide nutrients to the embryo for about 9 months until the uterus contracts, pushing the fetus out through the
and will exit through the vagina in a process called
Vagina
Menstruation

19. Application: The use in IVF of drugs to suspend the normal secretion of hormones, followed by the use of artificial doses of hormones to induce superovulation and establish a pregnancy.

20. Application: William Harvey’s investigation of sexual reproduction in deer.
Nature of science: Developments in scientific research follow improvements in apparatus—William Harvey was hampered in his observational research into reproduction by lack of equipment. The microscope was invented 17 years after his death.