Cell signalling Flashcards
What is the purpose of cell communication?
Homeostasis
Self preservation
Processing information
Voluntary movement
What is endocrine communication?
Endocrine glands consider the direct secretion and release of hormones int the blood
What is the process of glucagon secretion?
Glucagon is secreted by alpha-cells of islets of Langerhans
Traverses out of the pancreas and released into blood vessels
Binds to glucagon receptor (G-coupled receptor)
Secondary messenger system to increase hepatic glucose output
What type of receptor are glucagon receptors?
G-coupled receptors
What are the examples of endocrine communciation?
Hormones travel within vasculature to bind onto distant target cell receptors
Insulin (Produced in pancreas, acts on muscle, liver and adipose)
Adrenaline produced by adrenal medulla
What is paracrine communication?
Denotes the secretion of hormones diffusion from the source to localized target cells
Describe the paracrine communication involved in hyperglycemia:
Insulin secretion by B-cells in the islets of Langerhans
Inhibits glucagon secretion
What is paracrine signalling?
Hormones act on adjacent cell
What are the examples of paracrine communication?
Osteoclast activating factor produced by adjacent osteoblasts Nitric oxide (mediates vasodilation) produced by endothelial cells
How do antigen presenting cells present antigens?
Antigens undergo internalization and fragmentation and the endoplasmic reticulum, proteases cleave antigen into antigenic fragments, associated to MHC molecules on cell surface membranes
What receptors bind to MHC Class 2 molecules?
TCRs
The interaction between T-cell receptors and MHC-II is an example of what?
Signalling between membrane attached proteins
What is autocrine signaling?
Communication with self
What is the examples exhibited by T-cells during autocrine cell signaling?
Secretion of IL-2 from activated T-Cell
Binds onto cell surface membrane receptor
IL-2 promotes differentiation into T-effector and memory cells
What are ionotropic receptors?
Ligand binding –> opens ion permeable pore traversing the membrane