Please turn in your 2
worksheets from last class after
the quiz if you haven’t already.
The Endocrine System
I NT R O DUCTION TO HU MA N G R O WT H A ND D E VE LO PMENT
What is the endocrine system?
• It includes all of the glands of the body and the hormones produced
by those glands.
• These glands regulate the function of organs in the body and therefore help to
maintain the body’s homeostasis.
• These functions include: cellular metabolism, reproduction, sexual development,
sugar and mineral homeostasis, heart rate and digestion.
What are hormones?
• Hormones are a chemical messenger that are released into the blood
stream. They control many of your body’s activities
• Gland = a group of cells or an organ that secretes hormones
The Hypothalamus
• Location: In the brain, inferior to the thalamus
• Purpose: It is responsible for the direct control of the endocrine
system through the pituitary gland.
• All of the releasing and inhibiting hormones affect the function of the pituitary
gland
The Eight Endocrine Glands
• Which do you remember?
1.
Pituitary Gland
2.
Pineal Gland
3.
Thyroid Gland
4.
Parathyroid Gland
5.
Adrenal Glands
6.
Pancreas
7.
Ovaries/Testes
8.
Thymus Gland
The Pituitary Gland
• Location: Small pea-sized lump
of tissue connected to the
hypothalamus
• Purpose: It produces 6
important hormones and is
controlled by the releasing and
inhibiting hormones of the
hypothalamus. Produces
hormones that control other
glands and that control the
growth of bones and the
movement of smooth muscles
The Pineal Gland
• Location: Pinecone shaped
mass found just posterior to the
thalamus of the brain
• Function: Produces the
hormone melatonin which
helps to regulate the sleepwake cycle
The Thyroid Gland
• Location: Butterfly shaped
gland located at the base of the
neck
• Function: Produces the
hormone thyroxin which
controls metabolism
The Parathyroid Gland
• Location: 4 small masses
located on the thyroid gland
• Function: Regulates calcium
and phosphorus in the body
The Adrenal Gland
• Location: Triangular glands
found near the kidneys
• Function: Send fight or flight
response to the brain and also
contains small amounts of
testosterone that may help
with secondary male sex
characteristics. It also controls
the body’s water balance
The Pancreas
• Location: In the abdominal
cavity
• Function: Produces glucagon
which is responsible for raising
blood glucose levels. It also
produces insulin which is
responsible for lowering blood
glucose levels
The Testes
• Location: Found in the scrotum
of males
• Function: Produces the
androgen testosterone after
the start of puberty which
effects the muscles, bones, sex
organs and hair follicles.
• Puberty occurs in males usually
between the ages of 12 and 15
The Ovaries
• Location: Almond shaped
glands in the pelvic cavity
• Function: Produces the female
sex hormone progesterone and
estrogen. Progesterone is most
active in females during
pregnancy and ovulation.
Estrogen causes female
secondary sex characteristics
• Puberty occurs in females usually
between the ages of 8 and 15
The Thymus
• Location: Triangular shape
organ found in chest
• Function: Helps protect the
body from pathogens. Becomes
inactive during puberty and is
slowly replaced by adipose
tissue.
The Female
Reproductive System
A B R IE F OVE R VIE W
About the Female Reproductive System
• Organs Include: Ovaries, Fallopian Tubes, Uterus and Vagina
• The ovaries produce egg cells (ova/ovum) and estrogen
• Each ovum is enclosed in a small hollow ball called a follicle
• A female is born with 200,000 to 250,000 immature egg cells and only 400 of
them will mature in her lifetime
During Puberty…
• The egg cells begin to develop
and each month one egg
matures and is released from its
follicle (called ovulation) and is
part of the menstrual cycle
• The menstrual cycle is
associated with hormone
production and ovulation
Process Continued
• The egg is released from the
ovaries and enters the Fallopian
Tube into the Uterus
• Once in the Fallopian Tube one of
two things can happen
1. The egg disintegrates or leaves
the body during the menstrual
flow
2. If sperm are present when an
egg moves through the fallopian
tube conception or fertilization
may occur
The Male
Reproductive System
A B R IE F OVE R VIE W
External Male Organs
1. The Penis - Used for reproduction and urination. The reproductive
function is to deposit sperm into the vagina
2. The Scrotum – Sac like pouch that holds each testis and helps
regulate the temperature for sperm production. It hangs lower from
the body so that the testes have a lower temperature than the rest
of the body which allows for the production of sperm.
Internal Male Organs
1. Testes – Male reproductive
glands that produce sperm
cells and testosterone
• Seminiferous Tubules – Network of
coiled tubes inside the testes
which produces sperm
2. Epididymis – Where sperm
pass after they are produced
and are stored
Internal Male Organs Cont.
3. Vas Deferens – The
epididymis leads to the Vas
Deferens which are thin tubes
that are a passageway for
sperm and storage for sperm
4. Seminal Vesicles – Two small
glands that secrete a fluid
that nourishes and helps the
sperm move
Internal Male Organs Cont.
5. Prostate Gland – A gland that
makes a fluid to help keep
sperm alive
6. Cowper’s Glands – Glands
that secrete a clear,
lubricating fluid
After Sperm are Produced
• Two options
1.
Sperm will be stored in the body
2.
Sperm will leave the body through ejaculation which is a series of muscular
contractions.
• Semen is a fluid that consists of the combination of sperm, fluids from the
seminal vesicles, prostate gland and Cowper’s glands.