Enables animals to respond to external changes and to control conditions inside the body
= communication system
(endocrine and nervous)
Chemical co ordination
= slow, prolonged process of communicating information throughout the body by way of
chemicals called hormones
A variety are secreted by special glands or tissues called endocrine glands.
These glands secrete chemical messages which carry information in the blood.
Hormone
- An organic chemical substance
- Usually a protein but sometimes a steroid
- Secreted by an endocrine gland
- Carried in the blood stream to its target organ(s)
- Where it regulates metabolic reactions
They do not last long in the body, as they are broken down by enzymes.
Target organ
(Can be a single gland or organ or scattered throughout the body)
Although hormones are carried in the blood, they can only effect certain cells.
The specific cells that respond to a given hormone have receptor sites for that hormone.
Endocrine gland
= a vascular, ductless gland that secreted hormones which are carried in the bloodstream to
their target organs
Exocrine gland vs endocrine gland
Exocrine: Secretions are carried in ducts to where they are needed
Endocrine: Do not have ducts and secretions are carried in the bloodstream to their target
organs
Exocrine
Endocrine
Glands - Red
Pituitary hormones - Blue
Other glands hormones - Green
Disorders - Purple
, Endocrine glands in the body
Hypothalamus
Or hypophysis
Hypothalamus
Controls the pituitary.
In the brain, just above the pituitary.
Secretes anti diuretic hormone (ADH) and oxytocin, which are stored in the posterior pituitary
gland.
The pituitary gland
This is the ‘master gland’ as it is the chemical co-ordinator of most of the endocrine glands.
It has a posterior and anterior lobe.
Controlled by blood
Controlled by nerves