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Flashcards in Homeostasis/Signalling Molecules Deck (43):
1

What single does of paracetamol can kill someone? Chronic dosing can affect the function of which organ?

10g

Liver function

2

What are endogenous signalling molecules?

Signalling molecules within the body

3

What are the two classes of exogenous signalling molecules?

Exogenous I = natural (e.g. Plant based)
Exogenous II = synthetic

4

Give two examples of endogenous I drugs

Morphine
Aspirin

5

What is the normal core body temperature?

37 degrees Celsius

6

What acts as the 'controller' in body temperature regulation?

Hypothalamus

7

Which responses would be seen after an increase in core body temperature? (2)

Sweat glands activated
Peripheral vessels dilate (vasodilation)

8

Which responses would be seen after a decrease in core body temperature?

Skeletal muscle contraction (shivering)
Peripheral vessels constrict (vasoconstriction)

9

Below which temperature is considered hypothermia?

35 degrees Celsius

10

Above which temperature is considered hyperthermia?

38 degrees Celsius

11

Endocrine signalling molecules (hormones) can be categorised into which 3 categories?

Hydrophilic 1 - CATECHOLAMINES
Hydrophilic 2 - PEPTIDES & PROTEINS
Lipophilic - STEROIDS

12

Give an example of a catecholamine signalling molecule

Noradrenaline

13

Give an example of a peptide and a protein signalling molecule

Oxytocin

Insulin

14

Give an example of a steroid signalling molecule

Testosterone

15

Where are the receptors for catecholamines?

In the plasma membrane

16

Where are the receptors for peptide/protein signalling molecules?

In the plasma membrane

17

Where are the receptors for steroid hormones?

Intracellular (cytosolic or nuclear)

18

What is the plasma half-life of catecholamines, peptides/proteins and steroids respectively?

Catecholamines = seconds
Peptides/proteins = minutes
Steroids = hours

19

What response do catecholamines result in after binding to its receptor?

Causes a change in membrane potential
Triggers synthesis of cytosolic second messengers

20

What response do peptide/protein hormones cause after binding to its receptor?

Triggers synthesis of cytosolic second messengers
Triggers protein kinase activity

21

What is autocrine signalling?

Signalling molecules released, act on receptors on the same cell causing Intracellular changes

22

What is paracrine signalling?

Signalling molecules released into nearby extracellular environment and bind to receptors on nearby cells, causing their effects

23

What is an example of a paracrine signalling molecule?

A neurotransmitter

24

What distance and timeframe do neurotransmitters typically work over?

~20nm

Milliseconds

25

What does an excitatory neurotransmitter do?

Increases firing rate post synaptically

26

What does an inhibitory neurotransmitter do?

Decreases firing rate post synaptically

27

Neurotransmitters can be grouped into which 3 categories with which exception?

Amino acids
Monoamines
Peptides

Exception = ACh

28

Is acetylcholine excitatory or inhibitory?

Excitatory

29

Name 4 monoamine neurotransmitters.
State whether they are excitatory, inhibitory or both.

Adrenaline (excitatory)
Noradrenaline (excitatory)
Dopamine (both)
Serotonin (excitatory)

30

Name 3 amino acid neurotransmitters.
State whether they are excitatory, inhibitory or both.

Glutamate (excitatory)
Glycine (largely inhibitory)
GABA (inhibitory)

31

Apart from neurotransmitters, which are the other local chemical mediators used in paracrine signalling?

Cytokines - e.g. Interleukins, histamine
Nitric Oxide
Eicosanoids - e.g. Prostaglandins

32

Which signalling molecules does autocrine signalling use?

Shares many paracrine signalling molecules - e.g. Cytokines and growth factors

33

What distance do autocrine signalling molecules typically work over once released from the cell?

Microns

34

What is RITE a mnemonic for? What does each letter stand for? What is an exception to this mnemonic?

Describing DRUG TARGETS

Receptors
Ion channels
Transporters
Enzymes

Chemotherapy drugs are an exception - work on structural proteins/dna

35

What is KING a mnemonic for? What does each letter stand for?

Describing different drug target RECEPTORS

Kinase-linked receptors
Ion channels (ligand-gated)
Nuclear/intracellular receptors
G protein coupled receptors

36

What is an example of a kinase linked receptor? How do they cause an effect?

Cytokine receptor

Binding results in phosphorylation of proteins ---> signalling cascade ---> gene transcription

37

What is an example of a nuclear receptor? How does it cause an effect?

Oestrogen receptor (lipid soluble molecule e.g. Steroids)

Binds to gene transcription factors ---> activates/inactivates a gene

38

What sorts of molecules bind to ligand gated ion channels?

'Fast' neurotransmitters e.g. ACh, GABA, NMDA

39

What sorts of molecules bind to GPCRs?

Hormones
Opiates
Slow neurotransmitters e.g. Muscarinic ach, serotonin, dopamine, adrenaline, noradrenaline

40

What are the three types of GPCR? What is the difference between them?

Gs, Gi and Gq

They activate different intracellular signalling pathways

41

What are the 4 major ion currents in cells?

Na+
K+
Cl-
Ca2+

42

How can phosphorylation help to facilitate/inhibit the activity of ion channels?

Phosphorylation of intracellular sites on the channels by PKA/PKC

PKA/PKC can be activated by GPCR pathways

43

Transporters are important in the re-uptake of neurotransmitters such as...

How is this done?

Noradrenaline
Serotonin
Glutamate

Co-transported with Na+ (symported)