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

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

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.

Understandings: Insulin and glucagon are secreted by β and α cells of the pancreas

respectively to control blood glucose concentration. Thyroxin is secreted by the thyroid gland to regulate the metabolic rate

and help control body temperature. Leptin is secreted by cells in adipose tissue and acts on the

hypothalamus of the brain to inhibit appetite. Melatonin is secreted by the pineal gland to control circadian rhythms. A gene on the Y chromosome causes embryonic gonads to develop as

testes and secrete testosterone. Testosterone causes pre-natal development of male genitalia and both

sperm production and development of male secondary sexual characteristics during puberty.

Estrogen and progesterone cause pre-natal development of female reproductive organs and female secondary sexual characteristics during puberty.

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.

Applications and skills:Application: Causes and treatment of Type I and Type II diabetes.Application: Testing of leptin on patients with clinical obesity and reasons for the failure to control the disease.Application: Causes of jet lag and use of melatonin to alleviate it.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.Application: William Harvey’s investigation of sexual reproduction in deer.Skill: Annotate diagrams of the male and female reproductive system to show names of structures and their functions.

Utilization: Hormones are used in a variety of therapies such as replacement therapies.Aims: Scientists are aware that the drugs women take in fertility treatment pose potential risks to health. Should scientific knowledge override compassionate considerations in treating infertile couples?

Topic 6: Human Physiology (2 hours)

6.6 Homework QuizDon’t forget to title this “6.6 Homework Quiz” so Mr. Lawton can find it.

1. What are the sex chromosomes that a human female has? What about a human male?

2. List any 2 secondary sex characteristics of males.

3. What is the function of insulin?4. Where is the hormone thyroxin made?5. What do you think would happen to you if

you had an underproduction of the hormone leptin?

Insulin

Glucagon

Leptin

Thyroxin

Melatonin

Testosterone

Estrogen

Biology Journal 11/11/2013

What does homeostasis mean?

What is a negative feedback loop? What does it have to do with homeostasis?


What are the roles of insulin and glucagon in balancing blood sugar?Which type of diabetes can develop as an adult? What could be a reason that it is a problem in this country?


Is blood clotting a positive or negative feedback cycle. How do you know?


When you eat salty foods, the salt is absorbed into your blood (through the small intestine). The kidneys detect this extra salty blood, and react by increasing the amount of water in the blood. This extra water dilutes the extra salt and brings the blood’s saltiness back to a specific amount.

How does a pregnant woman’s body decide when to give birth? The process begins when the uterus (womb) begins to release a hormone called oxytocin, which causes contractions. The brain detects oxytocin and the contractions, and begins to make more oxytocin. This causes even more contractions, which makes the brain release more oxytocin. This keeps escalating until the baby comes out.

Could this be positive or negative feedback? Explain why you think so.



Which of these pictures best represents positive feedback? Why do you think so? Which of these pictures best represents negative feedback? Why do you think so?

Negative feedback:Keeps your body in balance

Positive feedback:Takes things to the extreme

What could be 6 values that your body monitors and regulates through negative feedback?

Blood sugar concentration

Blood Pressure

Temperature

Water concentration

CO2 concentration

pH

Hormones and Homeostasis

Hormones are chemical signaling molecules. They are made by glands and transported by the blood. This is called the endocrine system.

Homeostasis is the processes in which the body monitors and maintains a stable internal environment.

What internal temperature is kept stable in the body?98.6° F or 37° CWhat is normal blood pressure?120/80 (the units of blood pressure are mmHg)

What is normal blood pH?

7.4What is normal blood sugar concentration?

80 mg/dl (that’s milligrams of glucose per decaliter of blood)

What is normal water concentration in the blood?Around 90% of blood volumeWhat is normal CO2 concentration in the blood?10 to 13 kPa (kilopascals, which is pressure)

What does your body do to regulate its temperature?

A gland (thyroid gland) monitors temperature

Too cold? Too hot?

Secrete thyroxin to speed up metabolic rate, raising temperature.

Stop thyroxin secretion to slow down metabolic rate, conserving energy and heat.

http://www.google.com/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRw&url=http://health.howstuffworks.com/human-body/systems/endocrine/why-thyroid-important.htm&ei=8awJVcH6FIizyAThzYEw&bvm=bv.88198703,d.aWw&psig=AFQjCNGKDvi9Is6htQ3iPTbmwuwRcm1FFg&ust=1426783843013608

What if your temperature gets too high or too low?

Fevers are caused by your own body! It is generally believed that fevers help the immune system to fight off an infection.

Hypothermia is when you body loses too much body heat to keep functioning normally.

Negative feedback is when the results of a process reduce the process itself.•This is how the body regulates homeostasis.

Cells in the pancreas regulate the glucose levels.

•High blood sugar: β-cells make insulin and glucose is stored

•Low blood sugar: α-cells makes liver release glucagon, increasing blood sugar

What are the names the disease that happens when this system is not working? What’s the difference between the names?

Type I diabetes:You are born with it. It is often an autoimmune disease, where your immune system attacks and destroys your β-cells.Type II diabetes: Adult-onset diabetes. This occurs as the body develops resistance to normal insulin functioning. It is closely tied to obesity.Gestational diabetes:Diabetes occurring in a pregnant woman. She will have high glucose levels, but returns to normal following birth.

Positive feedback is when the results of a process increase the process itself.•These are rare, because they make an imbalance

Clotting blood is a positive feedback cycle.•Damaged tissues release clotting factors, causing other cells to do the same. It starts a reaction culminating in a clot.

When you eat salty foods, the salt is absorbed into your blood (through the small intestine). The kidneys detect this extra salty blood, and react by increasing the amount of water in the blood. This extra water dilutes the extra salt and brings the blood’s saltiness back to a specific amount.


How does a pregnant woman’s body decide when to give birth? The process begins when the uterus (womb) begins to release a hormone called oxytocin, which causes contractions. The brain detects oxytocin and the contractions, and begins to make more oxytocin. This causes even more contractions, which makes the brain release more oxytocin, which escalates until the baby comes out.


Which of these pictures best represents positive feedback? Why do you think so? Which of these pictures best represents negative feedback? Why do you think so?

Negative feedback:Keeps your body in balance

Positive feedback:Takes things to the extreme

What are the hormones involved in gender?

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1. Pre-natal development of male sex organsSRY gene on the Y chromosome causes a surge of testosterone in the developing baby, causing a penis and testes to develop.

If Y chromosome is present, it’s SRY gene causes testosterone

surge

If Y chromosome is absent, no testosterone

surge occurs6 week old embryo(has no gender yet)

Functions of Testosterone:

2. Secondary sexual characteristics in pubertyIncreased muscle mass, pubic and body hair, male grows taller, voice deepens, increased aggression, sperm production begins.

Testosterone released during puberty




3. Sex Drive and AggressionTestosterone increases male sex drive and makes sperm production constant for his entire life. Aggression is likely an evolutionary adaptation for hunting, defense, and mate competition.


Andre the Giant was a person who suffered from acromegaly, in which the pituitary gland overproduces growth hormone (GH).

http://www.google.com/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRw&url=http://www.wwe.com/classics/the-legend-of-andre-the-giant-26086326/page-4&ei=R7sJVazuJIn5yQT9-oHADg&bvm=bv.88198703,d.aWw&psig=AFQjCNGuwDFopITuYd8R_rUqev69kmShsg&ust=1426787508409272

http://www.google.com/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRw&url=http://www.mixedmartialarts.com/thread/2157319/Andre-the-Giants-beer-drinking-world-record/?page%3D5&ei=absJVfo5i67JBIaIgLgN&bvm=bv.88198703,d.aWw&psig=AFQjCNGuwDFopITuYd8R_rUqev69kmShsg&ust=1426787508409272

1. Pre-natal development of female sex organsIf the SRY gene on the Y chromosome is absent, then estrogen and progesterone manufacture begins, and the fetus becomes a female.

Low levels of estrogen and progesterone (due to the presence a Y chromosome’s SRY gene)

High levels of estrogen and progesterone

(due to the lack of a Y chromosome’s SRY gene)

6 week old embryo(has no gender yet)

Functions of Estrogen and Progesterone:

2. Secondary sexual characteristics in pubertyFemale grows taller, development of pubic hair, voice deepens, changed distribution of body fat, development of breasts.

Estrogen and Testosterone released during puberty




determine

https://www.google.com/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRw&url=https://www.pinterest.com/pin/438889926159443295/&ei=VZ8JVZfXMsucygScmIKABw&bvm=bv.88198703,d.aWw&psig=AFQjCNG8f8kM58BjITu6lQE0a5XjLbhjeg&ust=1426780364812941

3. Regulation of the menstrual cycle. Much more on that to come…



The menstrual cycle is regulated by 4 hormones. It “begins” with menstrual bleeding, and repeats about every 28 days. What could be some reasons for this bleeding? Why does it happen?

Bleeding is when the uterus gets rid of the endometrium lining. This lining is what the uterus prepares to be the placenta, providing blood-borne nutrients to the baby, if the woman becomes pregnant.

http://www.obgynplano.com/doctors/wp-content/uploads/2010/08/Uterus.jpg

http://knowledgeserver.files.wordpress.com/2012/08/uterus.jpg


Right before ovulation, the hormones _________, _________, and _________ reach their highest concentration. The leftover part of the follicle that released the egg, now called the corpus luteum, releases the hormone _________, which causes the build up of the lining of the _________, called the endometrium. This will be shed during _________, if a female is not _________.


Right before ovulation, the hormones estrogen, luteinizing hormone (LH), and follicle stimulating hormone (FSH) reach their highest concentration. The leftover part of the follicle that released the egg, now called the corpus luteum, releases the hormone progesterone which causes the build up of the lining of the uterus called the endometrium. This will be shed during the mensturation if a female is not pregnant.

The Analysis and Evaluation portions of your IA are due on Wednesday, April 1st.

• This is the calculations, graphing, statistical analysis, and conclusion.

• Print off and turn in your whole IA thus far, so Mr. Lawton can refer to it.

• Use the checklists on your IA guide!• Do not wait until the night before to do it,

something will go frustratingly wrong with your graphing, and you’ll be horribly sad…

The hormones _________ and _________ stimulate a follicle to develop. Ovulation happens when the hormones _________, _________, and _________ reach their highest concentration. After ovulation, the follicle turns into a structure called _________, which will produce the hormone _________. But, when this structure disappears, and stops making hormone, then _________ happens. If a female becomes pregnant, however, then the endometrium becomes the _________, and produces the hormone _________, so that it is not shed, which would kill the fetus.

The hormones FSH and LH stimulate a follicle to develop. Ovulation happens when the hormones FSH, LH, and estrogen reach their highest concentration. After ovulation, the follicle turns into a structure called corpus luteum which will produce the hormone progesterone. But, when this structure disappears, and stops making hormone, then menstruation happens. If a female becomes pregnant, however, then the endometrium becomes the placenta and produces the hormone progesterone, so that it is not shed, which would kill the fetus.


What is the release of an egg (ovum) from the ovary called?

What is the structure called that develops this egg? What hormone does it make?

What does this structure turn into after releasing an egg?


What is the release of an egg (ovum) from the ovary called?Ovulation This is also when a female is most fertile.What is the structure called that develops this egg?

What does this structure turn into after releasing an egg?

FollicleImmature eggs are called oocytes.

Corpus luteumThis begins to make progesterone, before completely breaking down.


List the structures that a sperm cell passes through from spermatogenesis, to when it is released out of the penis through ejaculation.

6. Urethra carries sperm through the…

1. Testicle, where spermatogenesis happens.

2. Epididymis the cells mature3. Carried along vas deferens, where it passes through 2 glands…4. Seminal vesicle adds fructose and mucus5. Prostate adds fluids to neutralize acid in vagina

7. Penis where it exits the body


What makes FSH and LH?The pituitary gland in the brain.

What do FSH and LH make happen?They cause the formation of a follicle, and then ovulation.

What makes estrogen?The follicle

What makes progesterone?The corpus luteum (the follicle turns into the corpus luteum after it ovulates)

What do estrogen and progesterone do?They develop and maintain the endometrium layer in the uterus. (When these hormones disappear, the endometrium dies and is released through menstruation)


What is IVF? How does it work? What are some arguments for and against it?

Mr. Lawton needs your first IA in digital format!

This will benefit you, too! Submit it to turnitin.com and Mr. Lawton will keep it for you forever… (and you will want it later)

http://nyulocal.com/wp-content/uploads/2011/05/happy-student.jpg

http://basicprepacademy.com/wp-content/uploads/2013/06/StudentSmilingComputer_op_600x600.jpg

6.6 Reproduction

http://en.wikipedia.org/wiki/File:Glenn_Quagmire.png

What are the male sex cells called?

What are the female sex cells called?

What is a diploid cell?

What is a haploid cell?

Sperm, aka spermatozoa, aka male gamete

Eggs, or oova (when mature), or oocyte (when immature), aka female gamete

These have a full set of DNA (46 chromosomes in humans)

These have a half set of DNA (23 chromosomes in humans)

Review!

What kind of cells does mitosis make?

What kind of cells does meiosis make?

Mitosis starts with a body cell (diploid) and makes another identical body cell (diploid).

1 → 2 cells (identical)

Mitosis starts with a body cell (diploid) and makes 4 haploid cells that are all different.

1 → 4 cells (not identical, half DNA)

Review!

Mitosis

Meiosis

Gametes are haploid sex cells that fuse through fertilization in sexual reproduction to form a diploid embryo.

Whoa, that’s a lot of science vocabulary. Does it make sense to you?

1. Spermatogenesis in a testicle2. Maturation in epididymis3. Carried along vas deferens4. Fructose and mucus picked up at seminal vesicle5. Prostate adds fluids to neutralize acid in vagina6. Ejaculation through penis, through the urethra

A sperm cell’s journey…

About 250 million sperm cells are released during one male ejaculation!

TesticleSpermatogenesis happens here

BladderStores urine (not a reproductive organ)

EpididymisNewly formed sperm mature / stored here

ProstateAdds fluids to neutralize acid in vagina to sperm

Seminal VesicleAdds fructose and mucus

to sperm

UrethraDuct for urine or sperm Vas Deferens

Sperm travels through this tube during ejaculationPenis

Enters vagina to deliver sperm

What is this kind of chart called? Review!

What can we determine about the person from this chart?It’s a karyotype, a picture of all of a person’s chromosomes

We can determine that it is a male (XY sex chromosomes) and that this person has down syndrome (trisomy 21)

OvaryEggs and follicles

develop here

Oviduct (aka Fallopian Tube)

Egg (or embryo, if fertilized) travels to uterus

UterusHolds fetus and placenta

during pregnancy

Muscle WallContracts to push out fetus

and dead endometrium

EndometriumRedevelops every menstrual

cycle, turns into placenta during pregnancy

CervixCreates seal to block infections.

However, sperm, menstrual fluid, and babies pass through itVagina

Passageway for penis and fetus. Is acidic, to discourage infections

*Female reproductive organs do not share a passageway with urinary system, like it does in males.

FSH Stimulates oocyte (immature egg) development in ovary

LH Also stimulates oocyte development. Causes ovulation (release of mature egg)

Estrogen Develops endometrium

Progesterone Maintains endometrium. Stays high during pregnancy. Menstruation happens when this hormone level decreases.

Pituitary Hormones

Hormones of Ovaries These hormones are released by the pituitary gland.

These hormones are released by the ovaries.

1. Menstruation: endometrium (aka “menses”) breaks down and is shed.

2. Follicular phase: a follicle in the ovary develops and release a new egg.

3. Luteal phase: the follicle becomes the corpus luteum, which secretes progesterone, then disappears, triggering menstruation. If pregnancy happens, the placenta produces progesterone to prevent menstruation.

Phases of Menstrual Cycle

Menstruation

Red pill• It’s a placebo (no hormones)• Menstruation happens on

regular basis at this timeBlue Pill• It’s made with estrogen and

progestin (synthetic progesterone)

• When these hormones are high, the pituitary gland thinks the body is pregnant, so no ovulation occurs (thus no ability to become pregnant)

The Birth Control Pill

Cramps!If no fertilization (and pregnancy) occurs, the endometrium needs to be shed and replaced with a new one.• The endometrium breaks down as progesterone levels drop (because the corpus luteum,

which makes progesterone, degenerates)• The uterus muscle contracts, restricting blood flow to the endometrium, helping to kill

the endometrium cells, and then keeps contracting to force them out of the cervix.

Meanwhile in my uterus…

Cramps!

Up to 50% of women experience menstrual cramps, with around 15% suffering from severe pain. This is known as dysmenorrhea. Type I dysmenorrhea begins in puberty. Type II begins much later and could be a sign of an internal health problem.

http://www.google.com/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRw&url=http://howtogetridofall.com/how-to-get-rid-of-cramps&ei=EC0QVf6lHMGfyASLyoF4&bvm=bv.88528373,d.aWw&psig=AFQjCNFoxtoRS40GzSNj7Iibm7V2ynzFog&ust=1427209859342364






to sperm





develop here




during pregnancy









Male

Sperm cells start here and travel from…

Vas Deferens

to the…

Pituitary Gland

Progesterone

Female

Contains a gland called theWhich

makes a 2 hormones called…

Which stands

for

makes a hormone

called

Which causes the uterus to build theThe egg is eventually released; this is called

The leftover follicle changes into a structure called the

It makes a

hormone called

to the…

to the…

to the…

to the…

to the…

which causes the uterus to maintain the

Which stands

for

These 2 hormones stimulate the ovary to make a structure that will eventually release an egg; this structure is called a

If the egg is not fertilized, then there is a decrease in the level of the hormone

which will produce the hormone

and provide nutrients to the embryo for about 9 months until the uterus contracts, pushing the fetus out through the

If the egg is fertilized, then the endometrium becomes the

This causes the endometrium to die; it will be pushed out by contractions of the

and will exit through the vagina in a process called

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

function

function

function

function

function

function

function

Male


Sperm cells start here and travel from…

function

EpididymisSperm matures here and is stored until ejaculation

function

Vas Deferens Sperm travels through this tube during ejacultion

function

Seminal vesicleAdds fructose (a sugar for sperm food) and mucus (to lubricate sperm)function

ProstateAdds fluids that neutralize the acids in the vagina, to help the sperm survivefunction

Urethra A duct shared between urine and spermfunction

PenisEnters the vagina, delivering the sperm and semenfunction

to the…

Pituitary Gland

Brain

Ovulation

FSH

LH

Follicle Estrogen

Corpus Luteum Progesterone

Endometrium

Progesterone

VaginaProgesterone Uterus

Menstruation

Female

Contains a gland called theWhich

makes a 2 hormones called…

Follicle stimulating hormone

Which stands

for

Luteinizing hormone

makes a hormone

called

which causes the uterus to build theThe egg is eventually released; this is called

The leftover follicle changes into a structure called the

It makes a

hormone called

to the…

to the…

to the…

to the…

to the…

Placenta

which causes the uterus to maintain the

Which stands

for

These 2 hormones stimulate the ovary to make a structure that will eventually release an egg; this structure is called a

If the egg is not fertilized, then there is a decrease in the level of the hormone

which will produce the hormone

Vagina

and provide nutrients to the embryo for about 9 months until the uterus contracts, pushing the fetus out through the

If the egg is fertilized, then the endometrium becomes the

This causes the endometrium to die; it will be pushed out by contractions of the

and will exit through the vagina in a process called

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

What is going on in the uterus at these times?

Uterine walls are mostly “empty”

Menstruation(endometrium is shed)

Endometrium is building up, and up and up…

What is going on in the ovaries at these times?

Follicle matures

Follicle appears

Follicle turns into corpus luteumOvulation

Corpus luteum

disappears

What hormone does the follicle make?

What hormone does the corpus luteum make?

Estrogen

Progesterone

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!

Quiz, Quiz Trade1. Put your name and hour on the front of the note card

(the side with lines).2. Write 3 questions that you think will be on the test on

the front of the note card. Look at the topics guide Look at your old journals and notes Look at your review guides

3. Write the answers to these 3 questions on the back side of the note card.

Why is Quiz, Quiz, Trade a great activity?A. In order to create 3 questions, you are forced to

carefully anticipate what you think is on the test.B. You have to consider everything we studied, and

decide what is most important.C. You’ll discover what other students thought was

important.D. You have the potential to quiz yourself on at least

100 questions!So take advantage of it!






to sperm





develop here




during pregnancy









Kish’s notes:

6.6 Hormones, homeostasis and reproduction

Hormones are used when signals need to be widely distributed.

Insulin and glucagon are secreted by β and α cells of the pancreas respectively to control

blood glucose concentration.

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

Thyroxin is secreted by the thyroid gland to regulate the metabolic rate and help control

body temperature.Q: Why do we iodize our salt?

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.

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.

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.

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

• Urethra – transfer semen during ejaculation and urine during urination

• Penis – penetrate vagina for ejaculation of semen near the cervix

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.

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

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. (Do not talk about concentrations at this point)

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.

• 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.

End Kish’s notes

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

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