Endocrine and
Reproductive Systems
Animal Systems: Reproduction
Endocrine System:
Function:
The endocrine system regulates long-term
changes in the body such as growth and
development. It is made up of glands that
release their products into the bloodstream.
It also controls many of your body’s daily
activities
STRUCTURE
HORMONES– chemicals released in one part of the
body that travel through the bloodstream and affect the
activities of cells in other parts of the body.
• Hormones bind to specific
chemical receptors on cells.
• Cells that have receptors for a
particular hormone are called
target cells.
• If a cell does not have receptors
or the receptors do not respond
to a particular hormone, the
hormone has no effect on it.
• You can think of a hormone as a
chemical messenger
Glands

Gland – Organ that
produces and releases
a substance, or
secretion.

Two Types of Glands:
◦ Exocrine Glands –
Release secretions
directly to the organs
that use them through
ducts or tube-like
structures.
◦ Endocrine Glands –
Release hormones
directly into the
bloodstream.
1. Pituitary Gland ie. Master Gland
Function: controls other
endocrine glands and regulates
growth rate, reproduction, and
metabolism.
-produces Human Growth
Hormone
Disorders: Too much growth hormone can
result in a condition called gigantism.
8 ft
11 in
Robert
Wadlow
2. Hypothalamus – regulates hunger, thirst,
sleep, body temperature, and most involuntary
mechanisms
◦ links the nervous system to the endocrine system
via the pituitary gland.
3. Pineal gland– secretes melatonin which
responds to daylight and seasonal changes
(sleep/wake cycle)
4. Thymus gland - Hormones released by
the thymus gland help the immune system
(T-cells) develop during childhood. By
adolescence, this gland has shrunk
considerably in size
5. Adrenal glands - These glands release
several hormones such as adrenaline
(epinephrine & norepinephrine), which
triggers the body’s response to sudden
stress (fight or flight). Other hormones
affect salt and water balance in the kidneys
and general metabolism
6. Thyroid Gland
Hormone: Thyroxin
 Function: regulates the body’s overall
metabolic rate and controls calcium
levels in the bloodstream
 Disorders:
Hyperthyroidism - too much thyroxin; fast
metabolism (weight loss)
Hypothyroidism - too little thyroxin; slow
metabolism (weight gain)

7. Pancreas - Produces insulin
(lowers) and glucagon (raises) to
keep the blood sugar level
constant.
* Disorders: Diabetes
disease in which the
pancreas fails to produce
insulin or the body does not
properly use Insulin
8. Ovary - The female reproductive glands
release sex hormones that regulate egg
maturation and control the development of
2nd sex characteristics (estrogen,
progesterone)
* breast development; widen hips
9. Testes - The male reproductive glands
release a sex hormone that regulates
sperm production and controls the
development of 2nd sex characteristics
(testosterone)
* facial hair growth; voice deepen
Some Hormones
And Their
Functions
1.Antidiuretic
Hormone (ADH):
Decrease the amount
of water absorbed by
the kidneys
2. Insulin & Glucagon:
Regulate blood sugar
levels
3. Follicle Stimulating
Hormone (FSH):
Stimulates the
growth/maturation of
gametes
The Endocrine system working with
other body systems…

Nervous System: Hormones provide feedback to the

Reproductive System: hormone production for

Muscular and Skeletal System: endocrine system

Immune System: the development is controlled by

Digestive System: The endocrine system controls the
brain to affect neural processing.
sexual development to make offspring
controls the growth of both bone and muscles
the endocrine system
rate of metabolism
Reproductive System:
Purpose:
The reproductive system combines genetic
information from both parents (in most
animals) to produce new life forms.
This system produces sex cells (gametes),
delivers them, and protects a developing
fetus until birth.
Comparing Reproductive Systems
Asexual
Sexual
Involves one parent. As a result, the
offspring tend to have the same
genotype and phenotype as the parent.
involves the fusion of two gametes.
Sperm and eggs are sometimes
produced by the same individual and
sometimes produced by different
individuals.
Ex: Flatworms can divide into 2 halves; each half
grows into a separate organism. Cnidarians
undergo budding where a new individual grows
from and then breaks off of the parent individual.
Ex: Vertebrates
Genetically identical
Genetic variation
There are 2 major mechanisms of fertilization

external fertilization: Used by many aquatic
invertebrates. Eggs and sperm are
simultaneously shed into the water, and the
sperm swim through the water to fertilize the
egg

internal fertilization: The eggs are fertilized
within the reproductive tract of the female,
and then are covered with egg shells and/or
remain within the body of the female during
their development
Comparative Reproductive Systems
In most animals, individuals are either definite males
or females; however some species are
hermaphrodites. This is when one organism
produces both egg and sperm.
Ex: earthworms and garden snails
Parts of the Reproductive System
**Gametes:
Specialized sex cells
(sperm and egg)
Male
1. Penis - External sex organ,
delivers sperm to female
Male Reproductive System

The main organs of the male
reproductive system are the
testis.

The testis remain in the
scrotum (external sac)
outside the body cavity, where
the temperature is about 1-3⁰
lower than the normal
temperature of the body.

Lower temperature is
important for proper sperm
development.
Male
urethra- carries sperm and urine
through and out the penis
Sperm Development
1.
1.
1.
Sperm production resulting
from testosterone & meiosis
is in the seminiferous tubules.
Fully mature sperm are
stored in the epididymus
in between ejaculations.
From the epididymus, some
sperm are moved into a tube called the vas deferens.

2.
Extends upward from the scrotum into the abdominal
cavity.
Vas deferens merges with the urethra, the tube that
leads to the outside of the body through the penis.
Flow of sperm: seminiferous tubules epididymusvas deferensurethra
Semen

Glands (Prostate- neutralizes acids, Cowper’s lubricant, Seminal vesicle- nutrient) lining the
reproductive tract produce a nutrient- rich
fluid called seminal fluid.




Seminal fluid nourishes the sperm and protects
them from the acidity of the female reproductive
tract.
Combination of sperm and seminal fluid is
known as semen.
2.5 million sperm are found in one drop of
semen!
If sperm are released in the reproductive
tract of a female, the chances of a single
sperm fertilizing an egg, if one is available, is
quite good.
Female
Parts of the Reproductive System
1. OvariesThe primary organs in the female reproductive
systems; the female gametes (ova or egg)
2. Fallopian
Tubes - Transport
egg to uterus
3. Uterus – Organ
where fertilized
egg develops
4. Vagina - Birth
canal
If the egg implants…


The fetus will
develop in the
muscular organ
called the uterus.
After the fetus is fullterm, a woman goes
into labor. At this
time the cervix, a
muscular ring
between the uterus
and the vagina, will
dilate allowing the
baby to pass through.
http://www.youtube.com/watch?v=1IDRIdE05ko (elephant birth)
healthy cervix (above), baby in
uterus (below)
Parts of the Reproductive System
Female
5. Placenta - serves for gas
exchange and metabolic
products with mother
6. Umbilical cord- attaches
embryo to placenta
7. Amniotic fluid - keeps
the embryo moist and
protected
Placenta
Facts About the Female Menstrual Cycle



The cycle takes an average of 28 days.
Regulated by hormones produced by the endocrine
system, such as estrogen and progesterone.
Begins at puberty and continues until menopause.

Permanent stopping of the menstrual cycle is called
menopause.

Average age for menopause is about 51, but can occur anytime
between the late thirties and late fifties.

Day 1-5: If fertilization does not occur within
2-3 days, the unfertilized egg passes through
the uterus without implanting. The uterine
lining detaches from the wall and is
discharged, along with blood and the
unfertilized egg through the vagina. (this is
called menstruation)

Day 5-14: uterine lining thickens, preparing to
receive a fertilized egg

Day 14: release of a mature egg into the
fallopian tube. (this is called ovulation)

Day 14-28: The first 3-4 days of this stage,
the chance of fertilization is highest.
Female Reproductive Cycle
Phases of the Menstrual Cycle
1. Follicular Phase
2. Ovulation
3. Luteal Phase
4. Menstruation
View the following animation:
http://www.knowmycycle.com/cycle-closer.aspx
Endometriosis


When tissue from the uterus is found growing OUTSIDE
the uterus (ex. on the ovaries)
Treatment: attempts to remove endometrial tissue and
preserving the ovaries without damaging normal tissue
The Reproductive system working
with other body systems…

Nervous System: Reproductive hormones
affect brain development and sexual behavior.
◦ The brain controls mating behavior

Endocrine System: Endocrine Glands produce
hormones (ovary and testis)
1st
Trimester
(3 mo.)
2nd
Trimester
(3-6 mo.)
1st
Trimester
(3 mo.)
2nd
Trimester
(3-6 mo.)