The Endocrine and Reproductive Systems

What is the “endocrine” system?

“Endocrine” = hormones!

Endocrine system – made up of glands that release chemical messages into the blood (circulatory system).

Hormones

Hormones – the chemical messages released that affect the activities of other cells (target cells) in the body.

Hormones have specific shapes that allow them to bind to receptor molecules.

Receptor Molecules

Receptor Molecules – found on the outside of cell membranes.

Receptor molecules only bind with hormones of the same shape!

Gland

Gland – organ that produces and releases a chemical message (hormone).

- Ex: pancreas, testes, ovaries, etc.

Pancreas

Pancreas – an endocrine organ located behind the stomach.

- releases the hormone insulin to lower amount of glucose (sugar) in the blood.

Testes

Testes – male reproductive gland that releases the hormone testosterone.

- testosterone stimulates the production of secondary sex characteristics.

OvariesOvaries – female reproductive gland that

releases the hormones estrogen and progesterone.

- estrogen stimulates the production of secondary sex characteristics.

- progesterone prepares uterus for a fertilized egg.

Dynamic Equilibrium

Dynamic Equilibrium – the constant, small corrections an organism’s body makes in order to maintain homeostasis.

Normal

Time

Blood sugar level

Control of the Endocrine System

Hormones (and all body systems) are controlled by systems called Feedback Mechanisms:

1. Positive Feedback

2. Negative Feedback

1. Positive Feedback

Positive feedback – a change (stimulus) that creates a positive response and leads to more of that response.

2. Negative FeedbackNegative feedback – a change (stimulus)

that leads to canceling a response.

Thermostat senses room is cold.

Sends signal to turn on heat.

Room temperature goes up.

Negative feedback tells thermostat to stop turning on heat.

Negative Feedback (Example for Regents)

Brain detects high blood sugar level (lots of glucose).

Sends signal to pancreas to release the hormone insulin.

Sugar (Glucose) level in blood drops.

Negative feedback low glucose level in blood means stop insulin production.

Feedback in Plants

Guard cells – two crescent shaped cells that control the opening/closing of pores (stoma) in a leaf.

- Opens to let gases in/out (CO2/O2).

- Closes to conserve water.

- Gas exchange occurs during the process of photosynthesis.

Feedback in Plants

Reproductive Systems

Male Reproductive System

a. Testes

b. Vas deferens c. Prostated. Urethra

e. Penis

f. Bladder g. Rectum

Male Reproductive System

a. Testes – male reproductive organ that produce testosterone and sperm.

b. Vas deferens – tube that carries sperm from testes to the prostate gland.

c. Prostate – produce fluid for sperm.

d. Urethra – connected to vas deferens and takes sperm through penis.

e. Penis – releases sperm from the body.

Female Reproductive System

a. Ovary

Side Front

a. Ovary

b. Oviduct b. Oviducts

c. Uterusc. Uterus

d. Cervixd. Cervix

e. Vagina

e. Vagina

f. Bladder

g. Rectum

c. Uterus

f. Bladder

Female Reproductive System

a. Ovary – female reproductive organ that produces hormones and eggs.

b. Oviduct (fallopian tube) – tube that carries egg. Where fertilization occurs.

c. Uterus – site where embryo implants and develops.

d. Cervix – Outer end of the uterus.

e. Vagina – birth canal that leads to outside of body.

Menstrual Cycle

Summary of Menstrual Cycle

FertilizationFertilization – the process of a sperm

joining an egg.

- occurs in the oviduct (fallopian tube) of the female.

Facts about Fertilization:

a. 400-600 million sperm are released, only 1% make it to the oviduct.

b. When sperm and egg join, the two nuclei combine: 23 + 23 = 46 (humans)

c. Zygote – fertilized egg formed.

23

23

Types of Fertilization

1. External Fertilization – fertilization occurs outside of the organism’s body.- Ex: Fish, amphibians, etc.

2. Internal Fertilization – fertilization that occurs inside the organism’s body.- Ex: reptiles, birds, mammals, etc.

Differentiation

Differentiation – cells of the developing zygote become different from each other, or “specialized”.

- 3 layers of cells form:

a. Endoderm – inner layer (stomach, lungs)

b. Mesoderm – middle layer (bone, muscle)

c. Ectoderm – outer layer (skin, nerves)

Differentiation

Embryonic DevelopmentEmbryo – the zygote develops into an embryo.Uterus adapts to nurture embryo:a. Placenta – organ responsible for diffusion

of nutrients, O2/CO2, and wastes from mom to embryo.

b. Umbilical cord – connects placenta to embryo.

c. Amnion – fluid-filled sac that protects embryo.

Embryonic Development

Embryonic Development Animations

Amnion Fluid:

http://health.howstuffworks.com/adam-200127.htm

Placenta:http://health.howstuffworks.com/adam-200109.htm

Fertilization and Development Summary

1. Meiosis – produces haploid sperm and egg

2. Fertilization – sperm and egg meet to make a diploid zygote.

3. Differentiation – zygote divides by mitosis into an organism.

Fertilization and Development Summary

Meiosis n= 23

Fertilization 2n=46

Differentiation by mitosis 2n=46

New multicellular organism 2n=46

Plants have hormones too!Animals are not the only organisms that

use hormones!

Auxin – a plant hormone produced in the stem that promotes growth of plant.

Makes plant grow = Auxin power!!!YEAH BABY YEAH!!!!!

Negative Feedback Animation

http://pennhealth.com/health_info/animationplayer/homeostasis.html

Google: Key word “Medical Animation Library: Homeostasis”

What is the Purpose of Reproduction?

To form new individuals (offspring) of a species.

2 Types:

1. Asexual Reproduction – reproduction involving only one parent.

2. Sexual Reproduction – reproduction involving two parents.

Asexual Reproduction

Offspring are identical and contain same amount of genetic material as parents.

- Results from mitosis.

Ex: a. Budding

b. Binary Fission

c. Vegetative Propogation

d. Sporulation

e. Regeneration

Types of Asexual Reproduction

a. Budding – offspring grows out of parent cell and eventually separates.

-Ex: Hydra, yeasts

b. Binary Fission – parent cell splits into two new offspring cells.

- Ex: Amoeba

c. Vegetative Propagation – piece of one plant is cut and inserted into another plant. (grafting)

-Ex: Seedless fruits

d. Sporulation – spores are produced that are genetically identical.

-Ex: Dandelions, weeds

e. Regeneration - cells grow to replace limbs or tissues (identical).

- Ex: planaria, starfish

Sexual Reproduction

Offspring receive half of their DNA from one parent and half from the other parent.

- involves meiosis.

- offspring are not genetically identical to parents or to siblings (brother and sister).

The Menstrual Cycle

Menstrual Cycle – egg matures and is released from an ovary.

- cycle averages about 28 days.

- if fertilization occurs egg attaches to uterus

- if no fertilization egg is discharged

a. Follicular phase – egg develops and matures in the ovary.

- follicle grows around the egg to provide nutrients.

- pituitary gland releases FSH and LH hormones stimulate egg growth.

Growing “egg”

b. Ovulation – follicle breaks and mature egg is released from ovary.

- occurs around day 14.

- lots of LH hormone present causes follicle to break.

c. Luteal phase – after egg is released, the broken follicle becomes the corpus luteum.

- corpus luteum is yellow and releases progesterone hormone thicken uterus.

- if fertilization occurs walls of uterus thicken and egg attaches.

d. Menstruation – if no fertilization happens, corpus luteum and egg break down.

-hormone levels decrease and cycle starts over.

- walls of uterus “shrink” back to normal.

Menstrual Cycle Animation 1

http://www.msnbc.com/news/wld/graphics/menstrual_cycle_dw2.swf

Key word google: bio 122 menstrual cycle

“B-2 Endocrine system”

Menstrual Cycle Animation 2http://health.howstuffworks.com/adam-2

00017.htm

Google Key word: How stuff works Egg production

Early Developmentc. Differentiation (mitosis)

g. Uterus lining (endometrium)

a. Ovulation

b. Fertilization

d. Morula

e. Blastocyst

f. Implantation