Transcript Endocrine System

Endocrine System
Unit-P
The foundations of the
endocrine system are the
hormones (chemicals)
that are secreted by the
endocrine glands.
Objectives
• 1H16.01 Explain the structure of the
endocrine system.
• 1H16.02 Analyze the functions of the
endocrine system.
• 1H16.03 Discuss characteristics &
treatment of common endocrine
disorders.
• Main Functions -To
secrete hormones
• Body cells that react to a
particular hormone are ct
target cells.
• Cells that react to a
particular hormones are
called target organ cells.
• The 2 Types of Glands.
• ENDOCRINE
• EXOCRINE
ENDOCRINE
• Secretes hormones
directly into the blood
stream.
• Ductless
Exocrine
Secrete substance
through a duct and
release secretions in
the skin or inside of the
mouth.
Sweat, salivary, lacrimal
& pancreas
Hormone
Control
Negative feedback-drop
in hormone level
triggers a chain reaction.
a. Blood levels of hormone
b. Brain gets message &
sends out hormone to
stimulate.
c. Gland secretes more
hormones
d. When blood level of
hormone brain hormones
stop.
Nervous Control
In some cases, sympathetic
nervous system causes direct
release of hormone from gland
(for example, when stress
causes the adrenal medulla to
secrete adrenaline.
Adrenaline causes heart
contraction, vasoconstriction,
& increased heart rate.
Pineal Gland
• Melatonin is a
hormone secreted by
the pineal gland
which seems to play
an important role in
regulating sleeping.
Pituitary Gland
Master Gland
Has two Lobes-Anterior &
Posterior
1. Tiny structure size of
grape.
2. Located at base of the
brain in the cranial
cavity.
3. Connected to
hypothalamus.
4. Divided into anterior
and posterior lobes.
Anterior Pituitary Lobe
Functions
A. Controls growth hormone
B. Prolactin-development of breast tissue,
stimulates production of milk after
childbirth.
C. Thyroid-stimulating hormone-TSHstimulates (thyroid gland) thyroxine.
D. Adrenocorticotropic hormone-ACTHstimulates adrenal cortex.
F. Follicle Stimulating Hormone-FSHstimlutes growth of graafian follicle (in
the ovaries) & production of estrogen in
females, sperm in males. FSH/LH act on
the ovaries & testes.
G. Luteinizing Hormone-LH-stimulats
ovulation & formation of corpus luteum,
which produces progestrone in females.
Pituitary Gland
Posterior Pituitary Lobe
A. Vasopressin-converts to
ADH (antidiurectic
hormone) in the
bloodstream acts on
kidney to concentrate
urine & preserve H2O in
the body.
B. Oxytocin-released
during childbirth causing
contractions of the
uterus.
Thyroid Gland
1. Butterfly-shaped
mass of tissue.
2. On either side of
larynx, in front of
the trachea.
3. H-shaped.
Thyroid Function
1. Main hormone, thyroxine, is controlled by
secretion of TSH.
2. Thyroxine controls the rate of metabolism.
& stimulate cellar metabolism.
3. Calcitonin, another hormone that controls
calcium ion concentration in the body,
prevents hypocalcemia.
Thymus
1. Endocrine gland &
lymphatic organ.
2. Located behind
sternum, above and
in front of heart.
(thoracic cavity)
3. Begins to
disappear at puberty.
Adrenal Glands
Located on top of each
kidney.
Functions
Adrenal cortex secretes
Corticoids (anti-inflammatory
hormones) & sex hormones
Androgens-male sex hormones.
Adrenalin-hormone from adrenal
medulla, powerful cardiac
stimulant, produced response to stress
“fight or flight” hormone
Pancreas
Located behind the stomach.
Endocrine & exocrine functions.
FUNCTIONS
Islets of Langerhans-Insulin
production that utilization of
glucose (insulin blood sugar)
(Endocrine function)
After meals is when the
pancreas secretes the most
insulin.
Located in Abdominal cavity.
Parathyroid
Glands
1. Four glands, each the size of
a grain of rice. Located in the
neck.
2. Attached to posterior thyroid.
FUNCTION
Produce parathormone
which helps control blood
calcium, prevents hypocalcemia.
Tetany
Hypofunctioning of the
parathyriod glands leads to
tetany.
Decreased calcium
levels affect functions of
nerves.
Symptoms – Convulsive
twitching develops,
person dies of spasms
in the respiratory muscles
Rx – Vitamin D, calcium
& parathormone.
Gonads - located in pelvic cavity.
1. Ovary in female.
2. Testes in male.
Gonads Hormones
• Estrogen-development of
female reproductive
organs, secondary sex
characteristics.
• Progesterone-plays a part
in the menstrual cycle.
• Testosterone-male
reproductive organs &
secondary sex
characteristics.
Prostaglandins
Tissue hormones, can
cause constriction of
blood vessels, muscle
contractions. Can be
used to induce labor.
Common Endocrine Disorders.
Dwarfism
Hypofunction of pituitary in childhood. Defect in
growth hormone.
Small size, but body proportions & intellect
normal.
Rx – Early diagnosis, injection of growth
hormone. one or more body parts being
disproportionately large or small compared to
the rest of the body.
A person with an adult height of less than 4 feet
10 inches .
Midget
An extremely short but
normally proportioned
person.
Gigantism
Hyperfunction of
pituitary – Too much
growth hormone.
In preadolescence –
Overgrowth of long
bones leads to
excessive tallness.
Acromegaly is enlargement
of the bones of the hands,
feet & joints (protruding
chin-common symptom)
Hyperthyroidism
Overactive thyroid gland-Nervous irritability
Too much thyroxine leads to
enlargement of gland.
Symptoms – Consuming large
quantities of food but lose weight.
Goiter – Enlargement of gland low
dietary intake of iodine ( cause of simple
goiter.
Exophthalmos – Bulging of
Eyeballs
Tx.Partial/total removal of gland,
drugs to reduce include thyroxine
radiation
Hypothyroidism
Not enough thyroxine
May be due to lack of
iodine (simple goiter)
Symptoms – Dry, itchy
skin; dry and brittle hair,
constipation, muscle
cramps at night.
Diabetes Mellitus
Cause – Decreased secretion
of insulin.
Symptoms – Polyuria,
Polyphagia (insatiable appetite),
polydipsia, weight loss, blurred vision,
& possible diabetic coma.
If not treated, excess glucose in
blood (hyperglycemia) & secreted in
urine (glycosuria)
If too much insulin given, BS can get
too low (hypoglycemia) & person can
develop insulin shock.
Diabetes Mellitus
• A typical screening
procedure for
diabetes mellitus is?
Non insulin-dependent –
Most common, usually
familial, occurs later in life,
usually treated with diet.
Test for diabetes – Blood
sample at home, normal
blood sugar is 80-100 mg.
Hyperglycemia
(High Blood Glucose)
Causes: Too much food, too little
insulin or diabetes medicine,
illness or stress.
Onset: Gradual, may progress to
diabetic coma.
Symptoms: Extreme thirst,
frequent urination, dry skin,
hunger, blurred vision,
drowsiness, and nausea.
What can you do? Take blood
glucose tests, and if over 250
mg/dL for several tests, call your
doctor.
Hypoglycemia/Low Blood Glucose)
Causes: Too much insulin or diabetes medicine, or
extra exercise.
Onset: Sudden, may progress to insulin shock.
Symptoms: Shaking, fast heartbeat, sweating,
anxious, dizziness, hunger, impaired vision, weakness
fatigue, headache, and irritability.
Hypoglycemia
(Low Blood Glucose)
What can you do? Drink
½ glass of orange juice or
skim milk, or eat several
hard candies, test your
blood glucose; if
symptoms don’t stop call
your doctor, within 30
minutes after symptoms
go away, eat a light snack
(a ½ peanut butter or
meat sandwich and a ½
glass of milk.