16.2 - Principles of Coordination Flashcards
The role of the endocrine system How hormones act as chemical messengers Steroid and non-steroid hormones A comparison of hormonal and neuronal communication
What is the role of the endocrine system?
Use hormones to send information and bring about responses
What are endocrine glands?
Glands that secrete hormones directly into bloodstream
What are hormones?
- Chemical messengers
- bind to receptors on target cells
How do hormones act as chemical messengers?
5 steps
- Hormones are produced by endocrine gland cells.
- When stimulated, glands release hormones into the bloodstream.
- The blood carries hormones to their target cells.
- They attach to receptors on or inside the target cells.
- The cells then respond to the hormones.
What are the two classes of hormones?
Non-steroid and steroid
What is the solubility of non-steroid hormones?
Water soluble (hydrophilic)
What is the solubility of steroid hormones?
Lipid soluble (hydrophobic)
Can non-steroid hormones diffuse across the phospholipid bilayer?
Cannot
Can steroid hormones diffuse across the phospholipid bilayer?
Can
What is the mechanism of action for non-steroid hormones?
Bind to receptors on cell surface
What is the mechanism of action for steroid hormones?
Bind to receptors in cytoplasm or nucleus
What is an example of a non-steroid hormone?
Adrenaline
What is an example of a steroid hormone?
Oestrogen
How are signals transmitted in the endocrine system?
By blood
How are signals transmitted in the nervous system?
By neurones
What is the speed of transmission in the endocrine system?
Slow
What is the speed of transmission in the nervous system?
Very rapid
What is the spread of signals in the endocrine system?
Widespread
What is the spread of signals in the nervous system?
Localised
What is the duration of effect in the endocrine system?
Long
What is the duration of effect in the nervous system?
Short
