Transcript Endocrine System

Function
 Regulates mood
 Responsible for growth and development
 Tissue function
 Metabolism
 Sexual function and reproductive processes in the
body
Foundations of the Endocrine
System
 Hormones
 Transfers information and instructions from one set of
cells to another
 Glands
 Group of cells that produces and secretes, or gives off,
chemicals. A gland selects and removes materials from
the blood, processes them, and secretes the finished
chemical product for use somewhere in the body
Types of Glands
 Glands can be divided into two groups:
 Endocrine glands - glands that secrete their product
directly onto a surface rather than through a duct.
 Exocrine glands - secrete their products via a duct, the
glands in this group can be divided into three groups:
- Apocrine glands - a portion of the secreting cell's body is lost
during secretion
- Holocrine glands - the entire cell disintegrates and secrete its
substances
- Merocrine glands - cells secrete their substances by
exocytosis
Major Glands of the Endocrine
System
 Hypothalamus
 Pituitary gland
 Thyroid
 Thymus gland
 Parathyroids
 Adrenal glands
 Pineal body
 Reproductive glands (which include the ovaries and
testes)
Hypothalamus
 Collection of specialized cells that is located in the
lower central part of the brain
 Maintains homeostasis
 (examples: heart rate, body temperature, water balance,
and the secretions of the pituitary gland)
 Main link between the endocrine and nervous systems
 Nerve cells in the hypothalamus control the pituitary
gland by producing chemicals that either stimulate or
suppress hormone secretions from the pituitary
Pituitary Gland
 Located at the base of the brain
just beneath the hypothalamus
 Often called the "master gland"
because it makes hormones
that control several other
endocrine glands
 The production and secretion
of pituitary hormones can be
influenced by factors such as
emotions and changes in the
seasons
Pituitary Gland
 The pituitary is divided into two parts:
 anterior lobe- regulates the activity of the thyroid,
adrenals, and reproductive glands. The anterior lobe
produces hormones such as:
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Growth hormone- stimulates the growth of bone and other
body tissues and plays a role in the body's handling of
nutrients and minerals
Prolactin- activates milk production in women who are
breastfeeding
Thyrotropin- stimulates the thyroid gland to produce thyroid
hormones
Corticotropin- stimulates the adrenal gland to produce
certain hormones
Pituitary Gland
 posterior lobe
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helps control the balance of water in the body
Produces oxyton: triggers the contractions of the uterus in a
woman having a baby
 Secretes endorphins:
 chemicals that act on the nervous system and reduce
feelings of pain
Thyroid
 Located in the front part of the lower neck
 Shaped like a bow tie or butterfly
 Produces the thyroid hormones thyroxine and
triiodothyronine
 control the rate at which cells burn fuels from food to
produce energy.
 Help kids' and teens' bones grow and develop
Parathyroids
 Four tiny glands that
function together
 Release parathyroid
hormone:
 which regulates the level
of calcium in the blood
Adrenal Glands
 Triangular shaped
 Located above each kidney
 Each gland has two parts:
 Adrenal cortex, the outer part, produces hormones called
corticosteroids that influence or regulate salt and water
balance in the body, the body's response to stress,
metabolism, the immune system, and sexual development
and function.
 Adrenal medulla, the inner part produces catecholamines
such as epinephrine, also known as adrenaline. This increases
blood pressure and heart rate when the body experiences
stress.
Pineal Glands
 Located in the middle of the
brain
 Secretes melatonin:
 hormone that may help
regulate when you sleep at
night and when you wake in
the morning.
Reproductive Glands
 Main source of sex hormones are the gonads:
 sex gland in which gametes are produced
 Males
 Male gonads, or testes are located in the scrotum
 Secrete the hormone testosterone:
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Which affect many of the male characteristics such as penis
and height growth, deepening in the voice and growth in
facial and pubic hair and sperm production.
Reproductive Glands
 Females
 Female gonads, or ovaries are located on both sides of
the uterus, below the opening of the fallopian tubes
 Produce the hormones estrogen and progesterone
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Involved when a girl begins to experience breast growth,
accumulate body fat around the hips and thighs, a growth
spurt. Estrogen and progesterone are also involved in the
regulation of a girl's menstrual cycle and pregnancy
Thymus Gland
 Located in the upper part of the chest cavity, directly
behind the sternum
 Processes a type of white blood cell known as a Tlymphocyte.
 They help cells recognize and destroy invading bacteria,
virus, and abnormal cell growth such as cancer, and
foreign tissue.
Pancreas
 Also part of the digestive system
 Produces two hormones:
 Insulin and glucagon- work together to maintain a
steady level of glucose in the blood and keep the body
supplied with fuel to produce and maintain stores of
energy
Negative Feedback Mechanisms
 Main way to regulate blood levels of hormones.
 Rising hormone levels inhibit further hormone
release.
 Example: The thyroid gland has secreted the right
amount of thyroid hormones into the blood. The
pituitary gland senses the normal levels of thyroid
hormone in the bloodstream. Then the pituitary gland
adjusts its release of thyrotropin, the hormone that
stimulates the thyroid gland to produce thyroid
hormones.
Gland
Pineal
Pituitary
Hormone
Melatonin
ADH
Sleep cycles
Light and dark
Retention of water by kidneys
Hypothalamus reponse to
water/salt imbalance
oxytocin
Uterine contractions
Response to uterine stretching or
baby suckling.
GH
growth
hypothalamus
Prolactin
Milk production
hypothalamus
FSH
LH
Production of ova and sperm
hypothalamus
Stimulates ovaries and testes
hypothalamus
TSH
ACTH
Stimulates thyroid
Thyroxine in blood
Stimulates adrenals
glucocorticoids
Stimulates metabolism
TSH
Reduces blood Ca levels.
Ca levels in blood.
Raises blood Ca levels
Ca levels in blood
Epinephrine/norepinephrine
Increase blood glucose, rate of metabolism; constrict
blood vessels.
Nervous; sympathetic division
Steroids
Promote reabsorption of Na and excretion of K in
kidneys
Change in blood volume or
pressure.
Pancreas
Insulin
Reduces glucose
High glucose levels
Raises glucose
Low glucose levels
Testes
Glucagon
Androgens
Support sperm; male sex characteristics
FSH and LH
Ovaries
Estrogens
Female sex characteristics; stimulate uterine lining
growth
FSH and LH
Progesterone
Growth of uterine lining
FSH and LH
Thyroid
T4 and T3
Calcitonin
Parathyroid PTH
Adrenal
Action
Regulated by
Homeostasis:
 Menopause
 Late middle age, ovary function declines.
 Diabetes mellitus
 Hypothyroidism
 Hyperthyroidism
 Addison’s
 Hyposecretion of all adrenal cortex hormones
 Cushing’s disease
 Excessive output of glucocorticoids
Hypothyroidism
Hyperthyroidism
Acromegaly
References
 http://www.becomehealthynow.com/article/bodynervousadvanc
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ed/956/
http://kidshealth.org/teen/your_body/body_basics/endocrine.h
tml#
http://www.innvista.com/health/anatomy/thymus.htm
http://www.umm.edu/endocrin/reproduct.htm
www.endocrineweb.com/endocrinology/your-adrenal-glands
http://parathyroid.com/parathyroid-function.htm
http://www2.estrellamountain.edu/faculty/farabee/biobk/biobo
okendocr.html
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