Endocrine
system
p.971
1. What is endocrine system?
It is group of glands (organs)
They produce chemical signals to send messages between cells of the body
through blood
❖ Chemical signals allow cells to communicate
2. Its function (Regulation)
It helps body respond to changes in environment
It regulates metabolism, growth,
development, and reproduction
It maintains salt, water, and nutrients
balance in the blood
As they sweat, they lose water and salts
❑ Hormone produced by endocrine system cause kidney to
produce less urine to save water
➢ To prevent dehydration
❑ Another hormone cause kidney to filter salt from urine
➢ to avoid losing too much salt
Hormones
➢ Chemical messages sent by endocrine system
through blood
➢ They are substances that made in 1 cell or tissue
of body and cause changes in another cell or
tissue in different part of body (Target cell)
cause cells to change their activities
Hormones are produced by special cells of glands
Glands organs produce and release substances (hormones) to
target cell (to which hormone is directed to produce effect)
2 Types:
Exocrine
Endocrine Duct glands
Ductless glands Delivers (transport) nonhormonal
substances through ducts (tube-like
Make and Release hormones structures) To specific locations
directly into bloodstream As: sweat and salivary glands
Some organs are endocrine and exocrine glands as:
Pancreas
Endocrine Exocrine Delievrs digestive enzymes to
small intestine through ducts
Release hormones into
bloodstream
- Coordinate endocrine and nervous
system
- Maintain water balance in body
( Antidiuretic)
- Stimulate uterine contractions during
childbirth ( Oxytocin)
- Regulate other endocrine glands
- Regulate growth
- Stimulate milk production
- Control body’s response to stress
Control calcium balance
- Control mineral balance in blood
in blood
Parathyroid
gland
Testes
Regulate immune system Produce hormones for
reproduction (in males )
- Regulate metabolism Produce hormones for
- Stimulate calcium absorption by bone reproduction (in females)
Control blood-glucose levels
Controlling Endocrine system P.978
❑ Nervous system and 2 endocrine glands control release of hormones
❑ Both glands are located at base of brain
Hypothalamus Pituitary
(anterior)
Work together to conrol functions of
endocrine system
1. Hypothalamus Gland
- Coordinates (control) endocrine and nervous system
In nervous system: In endocrine system:
- Regulate autonomic nervous - Control release of hormones from
system pituitary gland
- Regulate Thirst, Hunger, and - Produce (oxytocin – antidiuretic)
body temperature hormones stored and released by
posterior pituitary
o Oxytocin o Antidiuretic (ADH)
o is called vasopressin
stimulates uterine
contractions during prevents dehydration
childbirth
By reducing amount of
water excreted by kidney in
urine
2. Pituitary Gland
- It is called master gland
- control release of endocrine glands
What?
- It is pea-sized gland
- Hangs by short stalk below hypothalamus
- Anterior pituitary produces 6 hormones
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6 hormones
4 of 6 hormones : 2 or 6 hormones:
- regulate hormone production in - do not regulate endocrine system
other glands
- They are called tropic hormones or
(Tropins)
- Tropins cause a change in the
hormone production of other glands
o Growth hormone (GH) o Prolactin (PRL)
- Stimulates growth of cells - Stimulates milk production in
- Affects bones and muscles women
13
Stimulate growth
And protein
synthesis
Growth stimulates uterine
hormone Oxytocin contractions
Anti diuretic during childbirth
GH hormone
Luteinizing Follicle-
hormone stimulating
hormone
Prolactin
Adrenocorticotropic Thyroid
hormone stimulating Reduce water
hormone excreted by
kidney in urine
Gland
Stimulate Milk Regulate production of sex Stimulate release
production hormones and development of of hormones from
eggs and sperms adrenal cortex 14
Anti diuretic (ADH)
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Pituitary Gland Disorders
- Hypersecretion and hyposecretion of tropins affect
endocrine glands that controlled by these hormones
1) Growth hormone (GH):
Hypersecretion = Too much Hyposecretion = Too little
o In Childhood o In adulthood o In childhood
➢ Gigantism ➢ Acromegaly ➢ Dwarfism
Person will be taller Growth in hands, feet, Person will be shorter than average
than average jaws, organs
If recognized early, treated by
- Can be fatal if not treated injection of synthetic growth
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hormone
Pituitary Gland Disorders
2) Prolactin hormone (PRL):
Hypersecretion = Too much Hyposecretion = Too little
o Women are not breast-feeding o women
and Men
➢ Are unable to breast-feed
➢ produce milk
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Regulating
Metabolism P.980
❑ Thyroid, Parathyroid, Pancreas, and pineal
Gland control metabolic processes
3. Thyroid Gland
Thyroxine
Functions Iodized Salt
Hormone ➢ United states eliminate iodine
➢ Regulate metabolic rate deficiency by iodized table
➢ Thyroid hormones are iodine-
➢ Control Growth, reproduction, based hormones salt
development ➢ Health organizations work to
➢ Contains iodine
➢ Control protein production provide iodized salt in every
➢ In case of iodine deficiency, country
➢ Control oxygen use by cells thyroid gland cannot function
properly and enlarged
thyroid Gland Disorders
Thyroid hormone:
Hyperthyroidism = Too much Hypothyroidism = Too little
➢ Nervousness
➢ Irregular heartrate o Children adult
➢ Weightloss
➢ Brain damage lack of energy
➢ Stunted growth dry skin
weight gain
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4. Parathyroid Gland
Parathormone
Functions Calcium
➢ Important mineral
➢ Parathyroid hormone raise calcium
levels into blood ➢ Required for:
➢ By make: nerve function and muscle
contraction
➢ bone cells release ➢ kidney reabsorb
calcium into blood calcium from urine
5. Pancreas Gland
Hormones Blood glucose
regulation
Insulin and glucagon
➢ High blood glucose level
➢ Insulin cause cell to absorb ➢ Glucagon cause liver cell to damage blood vessels and
glucose from blood then use it for release glucose organs
energy or store as glycogen
➢ So, glucagon raise blood glucose ➢ Low blood glucose level,
➢ So, glucose lowers blood glucose level
level brain cannot function
6. Pineal Gland
Functions Melatonin
➢ Disrupted by too much or
➢ Regulates body’s sleep cycle too little light
➢ Melatonin therapy treats ➢ Cause mood disorder called
1) insomnia
Hormone Seasonal affective disorder
(SAD)
2) mood disorders (SAD) ➢ Secretes melatonin
➢ Its release is stimulated by
darkness and inhibited by light
7. Gonads
Androgens Estrogen + Progestron
Regulates male development Regulates female development Stimulates changes in uterus
to prepare for implantation
Sexual Characteristics Sexual characteristics
8. Thymus Gland
Functions
➢ Responsible for maturation of T-cells (immune cell)
➢ Well developed
9. Adrenal Gland
Functions Hormone
➢ Increase heartbeats
➢ Secretes Adrenaline
➢ Increase glucose level in blood
➢ It is called fight and flight
➢ Cause sweating hormone
