PHGY 214 Lecture Notes - Lecture 6: Bloodborne, Adenylyl Cyclase, Phosphorylation
12 May 2016
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Document Summary
Are minute tunnels that bridge the cytoplasm of neighbouring cells in some types of tissues. Small ions and molecules are directly exchanged between interacting cells without ever entering the extracellular fluid: presence of identifying markers. Permits them to directly link up transiently and interact with cells. Ex) phagocytes of the body"s defence system specifically recognize and destroy only undesirable cells: extracellular chemical messengers. Signalling agents act on other particular cells, the messenger"s target cells. Neurotransmitters respond to electrical signals diffuse from their site of release across a narrow extracellular space to act locally. Hormones long range chemical messengers specifically secreted into the blood by endocrine glands blood carries messengers to other sites. Neurohormones hormones released into the blood by neurosecretory neurons respond to and conduct electrical signal do not directly innervate target cells neurosecretory neurons release blood-borne chemical messengers, ordinary neurons decree short-range neurotransmitters into a confined space.
