Download The Endocrine System

The Endocrine System
How our
hormones
function
The
Endocrine
System
Clip
What is the Endocrine
System?
 Series of cells, tissues, and
organs that secrete
hormones into body fluids
(blood).
 Hormone= a chemical
secreted by endocrine glands
which has a specific effect on
another cell or organ.
Where are the major
endocrine glands located?
• Added info
– Gland= organ that is made up of
epithelial tissue
– Secrete hormones.
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What do hormones
control?
Reproduction
Growth and development
Maintain homeostasis
Regulation of metabolism
Increasing bodies defenses
Gets “stuff” through cell
membranes.
How do hormones work?
 Hormones are produced by specialized cells
in glands.
 Glands secrete hormones into extra-cellular
fluids
 Blood transfers hormones to target sites
 Hormones cause changes in target cells
What organic compounds are
hormones made of?
 Amino acid-based hormones
 Steroids – made from cholesterol;
sex hormones, and adrenal cortex
 Prostaglandins – local hormones
made from lipids
What are the two types of
hormones? Fig 9.1
• Steroid Hormones
– Soluble in fat. Penetrate cell
membrane.
– Reach nucleus
• Nonsteroid Hormones
– Not soluble in fat. Bind to cell
membrane.
– Cascade of chemical reactions.
Steroid
Hormone
Adrenalin
The non Steroid
Hormone
How are Hormone Secretions
Controlled?
Negative Feedback System
Neg.
Sys.
Gland A secretes causing Gland B to
secrete. Gland B’s secretions inhibit A.
Like a thermostat.
Nerve Control
Controlled by the brain. Complicated.
There are Positive feedback systemsbut they are limited.
What can go wrong if there is a loss
of hormonal control?
• Dwarfism (Hypopitutiary dwarfism)
– GH= Growth hormone
– When inadequate amounts are secreted.
– Short, underdeveloped, lack full adult
sexual features.
– Treatment: Hormone therapy if diagnosed early
Dwarfism
Movies
Gigantism can also be an issue.
• Too much growth hormone.
• 8ft +
• Usually caused by a tumor that has
developed in the pituitary gland causing too
much GH to be secreted.
• Life expectancy is not full due
to strain on the heart.
The Pituitary Gland
 Location: Between the eyes and ears.
 Hangs by the hypothalamus stalk.
 Has two functional lobes
 Anterior pituitary – glandular tissue
 Posterior pituitary – nervous tissue
6 Hormones of the Anterior Pituitary Gland
Growth Hormone (GH)- Stimulates Mitosis
Prolactin- Milk Production After Birth of Baby
Thyroid Stimulating Hormone (TSH)- Plays role
in Metabolism
Adrenocorticotropic hormone (ACTH) And
Luteinizing hormone (LH)- Releases egg from
follicle & regulates testosterone
Pituitary
And
Hormones
Follicle Stimulating Hormone (FSH)- Stimulates
follicles to develop in the ovaries & sperm to
develop in the testes.
The 2 Hormones of the Posterior
Pituitary
 Oxytocin- Contracts uterus during labor
& stimulates milk ejection.
 Antidiuretic hormone (ADH)- Inhibits
urine production, can increase blood
pressure through
vasoconstriction/water retention.
Thyroid Gland
 Butterfly shape at the base of the throat
 Produces two hormones
 Thyroid hormones (T4 & T3) regulate the
metabolism of carbs, lipids, & proteins.
 Calcitonin decrease Ca+ in the blood
(more for your bones).
Thyroid Gland
Rotation
What can go wrong with the
Thyroid?
A goiter.
A lack of Iodine in the diet (3rd world
countries) or too much TSH (Thyroid
Stimulating hormone)
Thyroid
Gland
Tumor
Parathyroid Glands
Parathyroid Gland
Rotation
On each of the 4 corners of the
thyroid.
Stimulate osteoclasts to remove
calcium from bone
Stimulate the kidneys and intestine
to absorb more calcium
Raise calcium levels in the blood
Adrenal Glands
 Two glands
Cortex – outer glandular region
Medulla – inner neural tissue region
 Sit on top of the kidneys
Hormones of the Adrenal Cortex
 Glucocorticoids (including cortisone and
cortisol)
 Increases the use of fat, proteins (A.A)
and sugar when body needs energy
 Mineralocorticoids (aldosterone)
Regulate electrolyte balance
Target organ is the kidney
Hormones of the Adrenal
Cortex
 Sex hormones
Produced in the inner layer of the
adrenal cortex
Androgens (male) and some
estrogen (female)
Hormones of the Adrenal Medulla
 Produces two similar hormones that
prepare the body to deal with
short-term stress
Epinephrine
Norepinephrine
Pancreatic Islets
The pancreas,
Insulin, Glucose,
& Diabetes
 The islets of the pancreas produce hormones
 Insulin – allows glucose to cross plasma
membranes into cells from beta cells
 Glucagon – allows glucose to enter the blood
from alpha cells
 These hormones are antagonists that
maintain blood sugar homeostasis.
Pineal Gland
 Found on the third ventricle of the
brain
 Secretes melatonin
Helps establish the body’s wake
and sleep cycles
Thymus
 Located posterior to sternum
 Largest in infants and children
 Produces thymosin
Matures some types of white blood
cells
Important in developing the immune
system
Hormones of the Ovaries
 Estrogens
Stimulates the development of
secondary female characteristics
Matures female reproductive
organs
Also produced by the placenta.
Estrogen, continued
Helps prepare the uterus to
receive a fertilized egg
Helps maintain pregnancy
Prepares the breasts to
produce milk
Progesterone
Produced by the corpus
luteum
Acts with estrogen to bring
about the menstrual cycle
Helps in the implantation of an
embryo in the uterus
Hormones of the Testes
 Interstitial cells of testes are
hormone-producing
 Produce several androgens
Testosterone is the most
important of them.
Testosterone
Responsible for adult male
secondary sex characteristics
Promotes growth and maturation
of male reproductive system
Required for sperm cell production
Other Hormone Producing
Tissues and Organs
 Parts of the small intestine
 Parts of the stomach
 Kidneys
 Heart
 Many other areas have scattered
endocrine cells
 Placenta
Development Aspects of
the Endocrine System
Menopause
Growth hormone production declines
with age
Many endocrine glands decrease
output with age