Cell Signalling Flashcards
Why do cells need to communicate?
- Process information - sensory
- Self-preservation - reflexes
- Voluntary movement
- Homeostasis
Which cells secrete glucagon?
α cells of Islet of Langerhans in pancreas
In response to what is glucagon secreted and what does it do?
In response to hypoglycaemic features, stimulates glycogenolysis and gluconeogenesis
What is endocrine signalling?
Hormone travels within blood vessels to acts on a distant target cell
What is paracrine signalling?
Signalling molecules act on an adjacent cell
Insulin inhibiting glucagon secretion is an example of what type of signalling?
Paracrine signalling
Adrenalin acting on the trachea is an example of what type of signalling?
Endocrine signalling
Glucagon and insulin acting on the liver is an example of what type of signalling?
Endocrine signalling
Nitric oxide produced by endothelial cells causing vasodilation is an example of what type of signalling?
Paracrine signalling as they act on the nearby smooth muscle cells
What is signalling between membrane attached proteins?
Plasma membrane proteins on adjacent cells interacting
Hepatitis C detected are recognised by which cells in the bloodstream?
Antigen presenting cells (APC)
Osteoclast activating factors produced by adjacent osteoblasts is an example of what type of signalling?
Paracrine signalling
What happens after APC recognised the pathogen?
APC expressing major histo-compatibility (MHC) class II molecules on surface after digesting the pathogen
MHC II interacts with what to alert the lymphocytes?
T-cell receptor (TCR)
What type of signalling occurs between APC and T-lymphocyte?
Signalling between membrane attached proteins - Class II MHC and TCR
Interaction of HIV GP120 with CD4 receptors of T cells is an example of what type of signalling?
Signalling between membrane attached proteins
Bacterial cell wall components interact with toll-like receptors on haematopoietic cells in what type of signalling?
Signalling between membrane attached proteins
What is autocrine signalling?
Signalling molecule acts on same cell
What cascade of reactions occur after TCR activation?
Expression of IL-2 receptors → Secretion of IL-2
What types of signalling are involved in IL-2 secretion by T cells?
Autocrine and paracrine signalling - IL-2 binds to IL-2 receptors on same cell and adjacent cells
What type of signalling is involved in positive and negative self-feedback on neurones?
Autocrine signalling
ACh providing positive feedback for the presynaptic neurone is an example of what type of signalling?
Autocrine signalling - ACh binds to presynaptic M2-muscarinic receptors to promote NT secretion