Download Endocrine System

Endocrine System
Endocrine System
• Regulates overall metabolism,
homeostasis, growth and reproduction
• Glands – are ductless (tubeless) organs
that specialize in the secretion of
substances needed by an organism
directly into the bloodstream.
• Hormones – chemical substances that are
produced in glands and help regulate your
body’s functions. The secretions produced
by the endocrine glands
- released into the bloodstream
Endocrine Glands
• Hypothalamus – part of the
CNS, but it produces hormones
that influence the pituitary gland
• Pituitary Gland – the “master
gland” – regulates and controls
the activities of all of the other
endocrine glands.
- Located at the base of the
brain
- Secretes growth hormone
which affects growth of bone
and cartilage
Why is the Hypothalamus so Important?
• Secretes regulatory
homones
• RH
• RIH
• "Directs" pituitary
Pituitary
Pituitary
The pituitary gland
produces a growth
hormone which controls
growth and homeostasis.
Endocrine Glands (continued)
• Thyroid Gland
- Located in the neck
- Secretes thyroxine which regulates the
rate of metabolism in the body
• Parathyroid Gland
- Embedded in the back of the thyroid
- Secretes parathormone which controls
metabolism of calcium and phosphate
Thyroid
Thyroid
The thyroid gland produces
thyroxin to regulate
metabolism.
Parathyroid
Parathyroid
The parathyroid gland
produces parathormone
which controls calcium
levels in the body.
Endocrine Glands (continued)
• Adrenal Glands
- Located on top of the kidneys
- Secrete adrenaline which helps deal
with stress and accelerates the heart
and breathing rates
- Fight or Flight
• Islets of Langerhans – specialized cells
- Located in the pancreas
- Secrete insulin and glucagon
- Insulin lowers blood sugar
- Glucagon raises blood sugar
Adrenal Insufficiency
• Addison’s disease--hyposecretion of
cortisol
• JFK
• Darkened skin (ACTH mimics MSH)
• Weight loss, hypoglycemia
• Find the anomaly in the feedback loop.
• Inability to handle stress
Adrenals
The adrenal
glands Adrenals
Adrenals
produce adrenaline in
response to physical and
emotional stress.
Adrenal gland
Adrenal Problems
Liver and Pancreas
Pancreas
Pancreas
The pancreas produces insulin
which controls sugar levels in the
blood.
Endocrine Glands (continued)
• Gonads – sex glands
- Male gonads are called testes
- Located in the scrotum
- Secrete testosterone which regulates
male secondary sex characteristics
- Female gonads are called ovaries
- Located in the pelvic region
- Secrete estrogen and progesterone
which regulate female secondary sex
characteristics
Testes (in males)
Testes
The testes produce testosterone
used in sperm production and the
development of male traits.
Ovaries (in Females)
Ovaries
The ovaries produce estrogen used in
egg production and the development of
female traits.
Feedback Mechanisms
• Negative Feedback – is when an activity
alters a condition in the body, and this
triggers a series of events that reverses
the altered condition
Ex. Body temperature
- When body temp. goes up, we sweat
- When body temp. goes down, we
shiver
Ex. Blood sugar levels
- When blood sugar goes up, insulin
lowers blood sugar
- When blood sugar goes down,
glucagon raises blood sugar
A. Positive Feedback
• Not common
• Classic example:
Action of
OXYTOCIN on
uterine muscle
during birth.
Disorders
• Diabetes – is a disease where a person
cannot produce insulin
- Inability of the body to store sugar as
glycogen
• Goiter – is enlargement of the thyroid
gland caused by iodine deficiency
DIABETES
DIABETES
Goiter
Other Disorders
• Grave’s Disease: hyperthyroidism, an
autoimmune disorder in which an
overactive and enlarged thyroid gland
produces excessive amounts of thyroxine.
• Cushing’s Disease: overproduction of
adrenal hormones.
• Growth Disorders: abnormal amounts of
growth hormone.
GH as Juvenile (Gigantism)
GH = pituitary dwarfism
GH as an Adult