Transcript Chemical Regulation Endocrine System communication

Chemical Regulation
Endocrine System 
Communication
Endocrine System
Regulation of the human body
through chemical messengers called
hormones to maintain homeostasis
Homeostasis = stable internal
environment
Endocrine Regulation
Stimulus is detected
Impulse sent to brain
(hypothalamus)
Hypothalamus to pituitary
Pituitary sends message to gland
Gland releases a hormone
Hormone does work
New stimulus is detected
ENDOCRINE GLANDS
Pituitary = master gland
(controlled by the hypothalamus
in the brain)
Pituitary Gland
Releases hormone messengers (do not “do work”)
TSH – thyroid stimulating
hormone
ACTH – stimulates adrenal
glands
FSH – stimulates the ovaries
Oxytocin – labor
contractions
Calcitonin – Calcium
metabolism
ENDOCRINE GLANDS
Thyroid Gland – in neck
Releases Thyroxine which regulates
metabolism
Parathyroids – 4 tiny glands behind thyroid
Releases Parahormone regulates Calcium in
blood
Adrenal Gland– on top of kidneys
Releases Adrenaline which allows the
body to respond appropriately in times of
emergency or stress
“Fight or Flight”
Pancreas – glands located within the
pancreas
– Releases Insulin which regulates blood sugar
levels
Diabetes – caused by decreased amounts of
insulin which leads to increase blood sugar 
coma  death if not medicated
GONADS – sex glands
Ovaries
Releases Estrogen – 2nd
degree sex
characteristics/ cycle
Releases Progesterone –
cycle and maintain
pregnancy
Testes
Releases Testosterone –
2nd degree male
characteristics and
production of sperm
Feedback Mechanisms
A cycle in which the output “feeds back” to
modify or reinforce the action of the system
2 types:
(a)Positive feedback
Change in the environment – increases the
response
Ex: uterine contractions during labor
(a)Negative feedback most common
Change in the environment  creates a
response message  makes a change 
stops the response message
Ex: regulate blood sugar
Sensor detects
high blood sugar
Pancreas
Negative
secretes
feedback
shuts
off insulin
production
insulin
Blood sugar
drops
- Ex: increase exercise increased muscle activity
increases HR and BP and resp. rate  O2 to
muscles
Disease
Disease = failure of homeostasis – the body
fails to work as it should
Causes of disease:
1) Pathogens – organisms (germs) that invade
the body ex: virus, bacteria, fungi. And
parasites (spread) – Lyme, cold
2) Uncontrolled cell division
Cancer
mass of abnormal cells called tumor
3)
4)
5)
6)
7)
Inherited ex: CF, Down’s
Poor nutrition
Toxins
Organ malfunction
High risk – skin/lung cancer