Flashcards in Signalling Processes Deck (72):
What is cell signalling?
Complex system communication that:Governs basic cell activitiesCoordinates cell actionsThis ability is the basis of development, tissue repair, immunity and homeostasis
`List examples of what signalling is important for?
Development and growthMaintaining homeostasisFighting infectionsRepairing injured tissueInitiating and coordinating movementCognition
What diseases can be caused by cell signalling gone wrong?
CancerAutoimmune diseasesDiabetesMSParkinson'sSchizophreniaEpilepsyHuntington'sALS/ Motor neurone disease
How does signalling occur in the body?
Chemically or electrically, using a variety of messengers
What are the types of messengers involved in cell signalling?
IonsAmino acids, peptidesCytokinesNeurotransmittersHormonesNeurohormones
What is a hormone?
A messenger released by a cell/ gland that binds with specialised receptors on a target cell
What is a neurohormone?
Any hormone produced and released by neurons.
What does the signalling cell initially do?
Secretes a substance which acts as a chemical messenger
What is the role of the chemical messenger/ ligand in signalling?
Binds with specialised receptors on the target cell.
What part of the signalling process produces a response in the target cell?
Binding of the messenger to the receptor
What are the short-range signals?
Direct, Intracrine, Autocrine, Juxtacrine
What is a type of medium-range signal?
What is a type of long-range signal?
What are direct signals?
Substance passes freely between adjacent cells through channels
True or false? Direct signals are a type of juxtacrine signalling?
Give an example of a direct signal
What are intracrine signals?
The substance acts within the cell
Give an example of intracrine signals
What are autocrine signals?
Substance acts upon the cell that secreted it
What are examples of autocrine signals?
Growth factor hormonesImmune cells
What are juxtacrine signals?
Substance acts upon adjacent cells in direct contact with it
What are examples of juxtacrine signals?
Notch signallingGap Junctions
What are paracrine signals?
Substance acts upon cells nearby
What are examples of paracrine signals?
Clotting factorsAllergic responseNeurotransmitters
What is the difference between paracrine and direct/ juxtacrine signals?
Paracrine signals are medium-range while the others are short-range
What are endocrine signals?
Substance acts upon cells throughout the body (long-distance)
What is an example of an endocrine signal?
What is a nexus?
A gap junction (synonym)
Give examples of where gap junctions can be found
Heart - In intercalated disksRetina - Interconnecting horizontal cells
True or false? Juxtacrine action does not require physical contact between the two cells involved
True or false? The same substance can act across a variety of distances?
How can neurotransmitters allow for distant signalling throughout the body?
What travel process do neurotransmitters and hormones have in common?
Approximately how long do nerve signals take to travel?
Are target effectors involved in the endocrine pathway or the neurohormone pathway?
If you are Schizophrenic you have high levels of... what?
If you have anxiety you typically have low levels of... what?
If you are happy you typically have high levels of... what?
If you have depression you typically have low levels of... what?
If you are in love you typically have high levels of... what?
In the fight/flight response, you typically have high levels of... what?
How do hormones reach their target cells?
Via the bloodstream
What is actually responsible for the hydrophobicity in the bilayer?
Are hormones water-soluble or lipid-soluble?
Both- depends on the type of hormone
Are neurotransmitters water-soluble or lipid-soluble?
Are growth factors water-soluble or lipid-soluble?
Are cytokines water-soluble or lipid-soluble?
Is insulin water-soluble or lipid-soluble?
Is glucagon water-soluble or lipid-soluble?
Is adrenaline water-soluble or lipid-soluble?
True or false? Acetylcholine, glutamate and cortisol are all water-soluble?
False- Cortisol is lipid- soluble
True or false? Testosterone, Oestrogen and Progesterone are all lipid-soluble?
True or False? Histamine, Thyroxine and Prostaglandins are all lipid soluble?
False- Histamine is water-soluble.
What is a term used to describe steroid hormones?
How does signal binding to a specific receptor on the target cell lead to a response?
Binding activates cytoplasmic enzymesThese enzymes alter cell behaviour and functions
What is cytosol?
Intra-cellular fluid present inside cells, the part of the cytoplasm that is not held by any of the organelles in the cell.
What is the difference between cytosol and the cytoplasm?
Cytosol is the part of the cytoplasm that is not held by any of the organelles in the cell.Cytoplasm is the part of the cell which is contained within the entire cell membrane.
What receptors do water-soluble signal molecules bind to?
Receptors at the cell surface
What are the three main classes of cell surface receptors?
* Ligand gated ion-channels
* G-protein coupled receptors
* Kinase linked receptors
What are ligand-gated ion channels? Where can they be found?
Gated pores for Na, K, ClTriggered by neurotransmittersIn the nervous system
How do ligand gated ion-channels work?
Recieve the signalAct by letting ions through the membrane
How do G-protein coupled receptors work?
Recieve the signalRely on G-protein to pass the signal to an effector enzyme
How do kinase linked receptors work?
Recieve the signalPass on the signal through intrinsic enzyme activity or by activating a kinase
What do GPCRs and kinase linked receptors trigger?
Intracellular signalling cascades
What causes altered cell behaviour?
Cytoplasmic machinery is affected
What is the second messenger in signalling?
Often the first product transiently formed to transduce the signal into the cell
What are 3 types of effector proteins?
* Metabolic enzyme
* Gene regulatory protein
* Cytoskeletal protein
What is the purpose of intracellular signalling cascades?
To amplify the initial signal
What are common second messengers?
What are the two types of kinases?
Serine/ Threonine kinasesTyrosine kinases
What are G-proteins?