Extracellular Signalling Molecules Flashcards
Where are endocrine signalling molecules secreted?
Directly into the blood
What does it mean by saying that endocrine molecules are highly potent?
Small changes in concentrations of these molecules result in large responses.
What are the 3 major types of endocrine signalling molecules?
- Amines (hydrophilic, small receptors in plasma membranes)
- Peptides to Proteins (hydrophilic. Receptors in plasma membrane)
- Steroids (lipophillic. Receptors are intracellular)
How do steroid hormones promote an action?
The receptor hormone complex controls transcription and stability of mRNAs
What mechanisms of action do protein hormones have?
Trigger synthesis of second messengers. They also trigger protein kinase activity
What mechanism of action do amine hormones use?
Trigger synthesis of second messengers. Cause changes in membrane potential.
What are the 3 main extracellular signalling groups?
Endocrine, paracrine and autocrine
What is paracrine signalling?
Where molecules are secreted by cells into the extracellular environment to induce chances in neighbouring cells
What is an example of a paracrine signalling molecule
Neurotransmitters
What are the 3 major types of neurotransmitters?
Amino acids, Monoamines, acetylcholine
What 2 roles can neurotransmitters have?
Excitably and inhibitory
What is a local response by paracrine signalling molecules?
Where there is a rapid response by surrounding cells to a problem without the need of involving the whole body
Cytokines (e.g. Interleukins, chemokines and histamine) are an example of what type of extracellular signalling molecule?
Local chemical mediators within the paracrine signalling molecules
What happens in autocrine signalling?
Cells respond to the signalling molecules they produce and release themselves
Why are signalling molecules important?
To regulate the conditions within the body precisely
