THE ENDOCRINE SYSTEM
Presented by: Quimson, Donna
masses of tissue found
in various parts of the
body. At the base of the
brain, in the neck,
behind the stomach,
above the kidney and
within and below the
• The glands are controlled directly by stimulation
from the nervous system as well as by chemical
receptors in the blood and hormones produced
by other glands.
• By regulating the functions of organs in the
body, these glands help to maintain the body’s
• Cellular metabolism, reproduction, sexual
development, sugar and mineral homeostasis,
heart rate, and digestion are among the many
processes regulated by the actions of hormones.
• It is also known as the hypophysis
• It is a small pea-sized lump of tissue connected
to the inferior portion of the hypothalamus of
• It has an anterior lobe and posterior lobe.
a. Anterior Pituitary Hormones
• Consists largely of epithelial cells
• Secretes the Growth Hormone(GH),
Prolactin(PRL), Thyroid stimulating hormone,
ACTH, FSH, and LH.
• Growth Hormone(GH)
-Stimulates body cells to increase in size and rate
-Promotes breast development and stimulates
-In males, prolactin decreases the LM
• Thyroid Stimulating Hormone(TSH)
-Controls the secretion of hormones from the
• Adrenocorticotropic hormone( ACTH)
• Follicle- stimulating hormone(FSH)
b. Posterior Pituitary Hormones
• Consists largely neuroglial cells and nerve fibers
that originate in the hypothalamus.
• The two hormones of the posterior pituitary are
produced in the hypothalamus.
• Antidiuretic Hormone(ADH)
- Causes the kidneys to reduce the amount of
water they excrete.
- In high concentration, ADH causes blood vessel
walls to constrict, thus raising BP or blood
- The secretion of the ADH is regulated by the
- Has an antidiuretic effect and can cause muscles
in the uterine wall to contract, thus playing a
role in childbirth.
- Causes contraction of certain cells associated
with production and ejection of milk from the
milk glands of the breast.
a. Structure of the Adrenal Glands
• Also called as Suprarenal glands.
• Are small, triangular glands located on top of
• Made up of two distinct layers ─ outer adrenal
cortex and inner adrenal medulla.
b. Hormones of the Adrenal Medulla
• produces the hormones epinephrine and nor
• these hormones are synthesized from tyrosine and
are closely to each other.
• These hormones produce effects similar to those
of Sympathetic Nervous System.
• Secretion of this hormone is stimulated by
Sympathetic Nervous System.
c. Hormones of the Adrenal Cortex
• Produces a variety of steroids that include
- causes the kidneys to conserve Na ions and later
to excrete potassium ions.
- It is secreted in response to decreased Na ion
concentration, increased K ion concentration.
- Maintains the synthesis of proteins, promotes
the release of fatty acids, and stimulates the
formation of glucose from non- carbohydrates.
• Adrenal sex hormones
- These hormones are male type although some
can be converted to female hormones.
- They are thought to supplement the sex
hormones produced by gonads.
• Is a butterfly-shaped gland located at the base of
the neck and wrapped around the lateral sides of
• The thyroid gland produces three major
hormones─ Calcitonin, Tri-iodothyronine
(T3) and Thyroxine (T4)
b. Thyroid Hormones
• Thyroxin and tri- iodothyronine
- Increase the rate of metabolism, enhance protein
synthesis, and stimulate the breakdown of lipids.
- Needed for normal growth and development ,
also for the maturation of the nervous system.
- lowers the blood calcium and phosphate ion
- Prevents prolonged elevation of calcium after a
• The parathyroid glands are 4 small masses of
glandular tissue found on the posterior side of
the thyroid gland.
• It makes Parathyroid hormone, which regulates
the level of calcium in the blood, so that nervous
and muscular systems can function properly.
a. Structure of the Pancreas
• Is a large gland located in the abdominal cavity just inferior and
posterior to the stomach.
• It is a glandular organ in the digestive systemand endocrine
system of vertebrates.
• The endocrine portion, which is also called the ‘Islets of
Langerhans’ secretes glucagon, insulin and somatostatin.
• It is considered to be a heterocrine gland as it contains both
endocrine and exocrine tissue.
b. Hormones of the Pancreas
• Glucagon stimulates the liver to produce
glucose, causing an increase in the concentration
of the blood glucose. It also promotes the
breakdown of fats.
• Insulin promotes the movement of glucose
through cell membranes, stimulates the storage
of glucose, promotes the synthesis of proteins
and stimulates the storage of fats.
• Are the sex puberty glands w/ produe
the sperm and eggcells for
• The pineal gland is a small pinecone-shaped mass of
glandular tissue found just posterior to the thalamus
of the brain.
• produces the hormone melatonin that helps to
regulate the human sleep-wake cycle known as the
• The activity of the pineal gland is inhibited by
stimulation from the photoreceptors of the retina.
• The thymus is a soft, triangular-shaped organ
found in the chest posterior to the sternum.
• The thymus produces hormones called
thymosins that help to train and develop Tlymphocytes during fetal development and
• part of the brain located superior and anterior
to the brain stem and inferior to the thalamus.
• It serves many different functions in
the nervous system, and is also responsible
for the direct control of the endocrine system
through the pituitary gland.
• The ovaries secrete estrogens and progesterone.
• The Placenta secretes estrogens, progesterone,
• The testes secrete testosterone.
• produced in the pineal gland and functions as an
antioxidant and control sleep.
• Excess hormone melatonin can cause lethargy,
liver disorders, eye disorders, fatigue,
disorientation, psychotic thoughts and behavior,
confusion, drowsiness, impaired speech,
trembling, headache and dizziness.
• produced in the digestive tract.
• controls the mood or mood, appetite and sleep.
• Excess serotonin can cause anxiety, confusion,
increased heart rate, dilated pupils, loss of
muscle coordination, sweating, diarrhea,
headache, chills, nausea, vomiting, convulsions,
high fever, irregular heartbeat, uncontrolled
movements and loss of consciousness.
• produced in the thyroid gland.
• serves to increase the basal metabolic rate and
affects protein synthesis.
• Excess thyroid hormone can cause diarrhea,
irregular heartbeat, headache, chills,
nervousness, stomach cramps, fever, chest pain,
or difficulty sleeping.
• It is produced in adrenal medulla
• This hormone serves to increase the supply of
oxygen and glucose to the brain and muscles (by
increasing heart rate), increasing catalysis of
glycogen in the liver, damage to lipids in fat cells,
and suppresses the immune system.
• Lack of adrenal hormones may cause dizziness,
headache, fatigue, weight loss, several intestinal
disorders, increased pigmentation of the skin,
depression, muscle pain and acute pain.
• produced in kidney and hypothalamus.
• serves to increase the heart rate and blood
pressure, inhibiting the release of prolactin and
TRH from anterior pituitary.
• Excess dopamine can cause nausea, vomiting,
headache, irregular heartbeat, chest pain,
difficulty breathing, changes in amount of urine,
skin discoloration, pain in legs and arms.
• This hormone is produced in the duodenum
(intestine 12 fingers), the which serves for
gastric acid secretion by parietal cells.
• produced in the anterior pituitary and serves to
stimulate the growth and reproduction of cells,
releasing the insulin-like growth factor 1 from
• This hormone deficiency in children can cause
growth failure and short body and delayed
sexual maturity. Whereas in adult growth
hormone deficiency is rare, but in some cases
can lead to obesity, decreased muscle mass and
energy reduction and quality of life.
• This hormone is produced in the pancreas and
serves to glucose uptake, glycogenesis and
glycolysis in liver and muscle of blood.
• Insulin deficiency can lead to hyperglycemia
(elevated blood sugar) which can lead to
• This hormone is produced in the testes and
serves as the male sex hormone. This hormone
stimulates the maturation of male sex organs,
scrotum, beard growth, the growth of muscle
mass and strength, and increase bone density.
• This hormone is produced in the ovaries, adrenal
glands and the placenta (during pregnancy).
• serves to raise the epidermal growth factor,
increases core temperature during ovulation,
reduces spasm and relaxes smooth muscle
(extending the respiratory tract and regulate
mucus), anti-inflammatory, reduces gall bladder
activity, normalization of blood and clotting of
• Source: rejekine.blogspot.com
Sense of sight, touch, hear, taste
• Aristotle (384 BC - 322 BC) is credited with the
traditional classification of the five sense organs:
sight, smell, taste, touch, and hearing.
• Immanuel Kant proposed that our knowledge of
the outside world depends on our modes of
perception. In order to define what is
"extrasensory" we need to define what is
• Each of the 5 senses consists of organs with
specialized cellular structures that have
receptors for specific stimuli. These cells have
links to the nervous system and thus to the
• Sensing is done at primitive levels in the cells
and integrated into sensations in the nervous
Sense of sight
Structure of the eye
- Transparent covering in front of the eye where light enters.
- sharply curved and serves as a preliminary lens, helping
focus the light
- Located behind the cornea
- The opening in the center of the eye that appears black.
- A ring muscle whose pigmentation gives the eye its color.
- Light passes trough a transparent structure
called the lens.
- The ciliary muscles attached to the lens modify
its curviture to focus the light so that it makes a
clear image in the retina.
- Surface at the back of the eye
- It is where the sense receptors for light are
located in the retina─ rods and cones.
• Rods and Cones
- Transform the electromagnetic energy of light
into neural impulses which are in turn
transmitted to the brain by the optic nerve,
leaving the retina at the back of the eyeball.
- the area of the retina where the optic nerve
leaves the eye does not have any photoreceptors.
It is referred as the blind spot, since there is no
visual response to the light that strikes this area.
- Small area in the center of the retina which
contains only cones while the area at the edge of
the retina contains only rods.
- The area between the fovea and the edge
contains both rods and cones.
- There are 100- 130 million rods and 6- 7 million
cones in the retina of each eye.
• Color perception is a complex process that
depends on psychological and physiological
• Two major explanations, the trichromatic
theory and the opponent- process theory.
a. Trichromatic theory
• was first advanced in the 19th century by Thomas
Young and later elaborated by the physiologist,
Herman von Helmholtz.
• Color vision is based on three types of cones thought
to be mingled in a mosaic pattern throughout the
• The proportion of each kind of cone activated
determines the color that is percieved.
• Any color of the visible spectrum can be produced
frome some combination of the three kinds of cones.
b. Opponent- process theory
• Developed by Ewald Hering
• based on the ways people describe colors rather
than on the mixing of colored lights.
• Hering used the phenomenon of after- images to
support his view that these four colors are paired
into opposing combinations: red- green and
• There are 3 types of cones─ one that respond to
brightness, one that responds to red- green, and
the one that responds to yellow- blue.
• During the daylight hours, they have normal
vision but as the light dims and the period of
twilight begins, they lose their sight.
• People with night blindness lose their sight
under low levels of illumination because their
retinas contain no rods or no functioning rods.
Sense of hearing
- Has three
and the inner
Structure of the Ear
• The ear has 3 major divisions:
1) the outer ear- the external projecting
portion, called the pinna and the auditory
2) The middle ear- separated from the outer
ear by the eardrum and containing three small
bones connectively called ossicles
3) The inner ear or cochles- the 3 semicircular canals, located in the inner ear, are not
part of the auditory system; they provide cues
to body position and movement.
Sense of taste
• The receptors for taste, called taste buds, are
situated chiefly in the tongue, but they are also
located in the roof of the mouth and near the
• They are able to detect four basic tastes: salty,
sweet, bitter, and sour. The tongue also can
detect a sensation called "umami" from taste
receptors sensitive to amino acids.
Sense of smell
1: Olfactory bulb
2: Mitral cells
4: Nasal epithelium
6: Olfactory receptor neurons
Sense of Smell
• Olfaction or Olfactory perception
• A form of chemical perception
• The nose is the organ
responsible for the sense
• Olfactory receptions: used
to detect the presence of smell.
• Glomerulus: a structure
which transmits signals to the
• Many vertebrates, including most mammal and
reptiles have two main distinct olfactory
systems─ main olfactory system and accessory
• For air-breathing animals, the main olfactory
system detects volatile chemicals, and the
accessory olfactory system detects fluid-phase
• Odorants: the chemicals that activate the
• Volatile small molecule odorants, non-volatile
proteins, and non-volatile hydrocarbons may all
produce olfactory sensations.
• In vertebrates smells are sensed by olfactory
sensory neurons in the olfactory epithelium.
• Humans have about 10 cm2 (1.6 sq in) of olfactory
• Each receptor cell has a single external process that
extends to the surface of the epithelium and gives
rise to a number of long, slender extensions
• Cilia: facilitating the detection of and response
to odour molecules by olfactory receptors.
• FUNCTION OF OLFACTORY SYSTEM: to smell,
when odour is inhaled it goes through the
olfactory epithelium which contains about 20
million nerve endings which are connected to
the brain for processing. The complex structure
of the olfactory system has the ability to dredge
up memories or even change moods after a
particular odour has been processed and
Disorders of Olfaction
Anosmia – inability to smell
Dysosmia– things smell different than they should
Hyperosmia – an abnormally acute sense of smell.
Hyposmia – decreased ability to smell
Olfactory Reference Syndrome – psychological
disorder which causes the patient to imagine he or
she has strong body odor
• Parosmia– things smell worse than they should be.
• Phantosmia – "hallucinated smell," often
unpleasant in nature
Sense of touch
• The sense of touch is distributed throughout the
• Four kinds of touch sensations can be identified:
cold, heat, touch, and pain.
- Has two main layers: epidermis and dermis
- the bottom layer is called subcutaneous
- consists of layers of skin cells with free nerve
- the epidermis is waterproof and serves as a
protective wrap for the underlying skin layers
and the rest of the body.
- It contains melanin, which protects against the
sun's harmful rays and also gives skin its color.
-contains very sensitive cells called touch
-includes sweat glands, blood vessels, hair
follicles, smooth muscles, and various sense
- filled with many tiny nerve endings which give
you information about the things with which
your body comes in contact.
• Subcutaneous tissue
- Composed of fat and connective tissues
- The layer of fat acts as an insulator and helps
regulate body temperature. It also acts as a
cushion to protect underlying tissue from
damage when you bump into things.
- The connective tissue keeps the skin attached to
the muscles and tendons underneath.
Kinds of touch sensations
• Warmth and Cold
- Felt when the skin is touched with stimulators
that are at skin temperature, usually 32 degrees
- Warmth is felt at temperatures greater than
- Cold is felt at temperature lower than
- Sensitivity to touch varies enormously over
different portions of the body.
- Many kinds of stimuli─ scratch, puncture,
pressure, heat, cold- twist─ can produce pain.
- The experience of pain is greatly influenced by
- they can protect you by warning your brain that
your body is hurt.