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Vertebrate Physiology > Chapter 5 Cell Signaling in Physiology > Flashcards

Chapter 5 Cell Signaling in Physiology Flashcards

1
Q

What is the importantance of Receptor Physiology?

A

Essential to both the nervous system and endocrine system functions

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2
Q

How do the nervous system and endocrine system functions work together?

A

Work together to maintain homeostasis

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3
Q

What is important about the nervous system?

A

It is fast, specific, quickly ends, uses neurotransmitters

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4
Q

What is important about the endocrine system?

A

Slow, longer lasting, less specific, uses hormones

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5
Q

What do both the nervous system and endocrine system use?

A

Both use chemical messengers (ligands) that bind receptors on target cells

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6
Q

What is pharmacology?

A

Study of chemical messengers acting upon receptors of cells/tissues

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7
Q

What does a receptor do?

A

Detect stimulu

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7
Q

What are examples of neurotransmitters?

A

ACh (acetylcholine), NE (norepinephrine), DA (dopamine)

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7
Q

What are neurotransmitters?

A

Chemical released by a neuron that acts primarily on postsynaptic cell
Ex. ACh, NE, DA, etc

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8
Q

What are intercellular signaling agents?

A

Or ligands
Neurotransmitters
Hormones
Neuropeptides

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9
Q

What are the types of hormones?

A

Hormonal, paracrine, autocrine, juxtacrine

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10
Q

What is Juxtacrine?

A

Cell-cell or cell-ECM signaling in which there is contact between structures involved

Contact dependent signaling

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11
Q
A
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11
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12
Q
A
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13
Q

What is paracrine?

A

Signals diffuse to and affect nearby cells

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14
Q

What is autocrine?

A

Term for hormones that act on same cells that secrete them

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15
Q

What is a neuropeptide?

A

2 or more amino acids joined by peptide bond(s)

Differ from other chemical messenger groups -synthesis method -location within neurons

Cleaved from larger, biologically inactive molecules

Synthesis occurs within soma & transported to synaptic terminals

Potent at very small amounts, neuromodulation

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16
Q

What are differences between neuropeptides and neurotransmitters?

A

NP: short chains of AA, serve as NT, slow acting, slow response, prolonged action, act on number of receptor proteins, alter gene expression

NT: endogenous chemical enable neurotransmission, fast acting, quick response, short term response, act on specific receptor, do not alter gene expression

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17
Q

How do neuropeptides differ form other chemical messenger groups?

A

Synthesis method

Location within neurons

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18
Q

What are large groups of neuropeptides?

A

Endogenous opiods

Opiates

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19
Q

What are endogenous opioids?

A

Beta endorphin
Enkephalins
Modulate pain awareness, eating, mood, drinking

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20
Q

What are Opiates?

A

Morphine, Codeine
Powerful opiates -> analgesics (pain reliever/pain killer)

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21
Q

What is the difference between an analgesic and an anesthetic?

A

Analgesic: decreases pain awareness but still conscious

Anesthetic; alters consciousness

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22
Q

What is a neuromodulator?

A

Variety of actions depending on specific neuronal interaction

Modulating neuronal activity

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23
Q

Neuromodulator alters postsynaptic cell causing

A

increase or decrease or inhibit synaptic activity

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24
Q

Neuromodulator alters presynaptic cell causing

A

impacting release, uptake, synthesis or metabolism of a NT

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25
Q

What are enkephalins?

A

Neuromodulator family

Small peptides

Inhibit (-) spinal interneurons from transmitting pain signals

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26
Q

What is nitric oxide (NO) ?

A

Simple neuromodulator

Lightweight gas, released by postsynaptic brain neurons involved in learning & memory

Stimulates presynaptic neuron to release more NT

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27
Q

What are characteristics about the types of receptors?

A

Most ligands are water-soluble and bind to external surface PM receptors

A minority of messengers are lipid-soluble

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28
Q

What do water-soluble receptors do?

A

Bind to external surface of plasma membrane receptors

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29
Q

What do messenger receptors do?

A

Steroids
Lipid-soluble and bind to intracellular receptors

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30
Q

What are plasma membrane receptors?

A

Usually a transmembrane protein
Ligands (peptides, protein hormones)
Water soluble
Hydrophilic (water loving)
Lipophobic (lipid fearing)
Usually activate rapid, short-lived response

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31
Q

What are ligands in plasma membrane receptors?

A

Peptides
Protein hormones

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32
Q

What are intracellular receptors?

A

Able to diffuse through lipid bilayer
Ex. Steroids, TH
Bind within cell to receptors in cytosol or nucleus
Lipid soluble
Hydrophobic (water fearing)
Lipophilic (lipid loving)
Usually alters gene expression
Require a transport protein
Often slower response but longer lasting compared to plasma membrane receptors

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33
Q

What are examples of intracellular receptors?

A

Steroids
Thyroid hormone

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34
Q

What is a hydrophobic signal?

A

Requires a carrier protein while in the plasma , but at the target cell the signal moves easily through the membrane and binds to its receptor, found either in the cytosol or in the nucleus

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35
Q

How do intracellular receptors alter gene expression?

A

Can act upon greater than or equal to 1 or more genes , can increase or decrease gene expression or both

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36
Q

What are the 4 major types of interactions between receptors and ligands?

A

Specificity
Affinity - also electric
Saturation
Competition

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37
Q

What is receptor - ligand specificity?

A

Ability of a receptor to bind only one type or a limited number of structurally related types of chemical messengers. Only cells that express the correct receptor can bind a particular messenger.

Not all cells express the same receptors, which leads to selective expression and specificity/ cell type/ tissue/ organ

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38
Q

Individual cells with the SAME receptor can also have a variety of responses based on,

A

Cell type
Intracellular signaling cascade coupling (ex. GLUT 1 GLUT 4)
Density of receptors
Structural integrity (defective or absent)

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39
Q

The more selective a receptor is

A

you are going to have a decreased amount of binding but a more specific response

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40
Q

What are examples of receptor ligand specificity?

A

AIS
Androgen Insensitivity Syndrome

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41
Q

What is AIS?

A

XY karyotype

Testosterone is secreted but defective or absent receptor, resulting in no masculinizing effects of testosterone

Default biological gender is female

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42
Q

What are receptor families?

A

There are many subtypes of a receptor “family”

Enables selectivity of drugs while decreasing unwanted side effects

Varied response due to receptor

Ex. ACh, NE, GLUT

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43
Q

What are examples of receptor families?

A

Acetylcholine, Norepinephrine, glucose transports

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44
Q

What is receptor - affinity?

A

The degree a receptor binds to a chemical messenger is determined by the affinity

Chemical structure
Electrical charge

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45
Q

At a higher affinity

A

bind at lower conc.
And may be effective at a lower therapeutic dose

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46
Q

At a lower affinity

A

Bind at higher conc
Greater therapeutic dose

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47
Q

What is receptor saturation?

A

The degree to which receptors are occupied by messengers. If all are occupied, the receptors are fully saturated; if half are occupied, the saturation is 50% and so on

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48
Q

In saturation, as ligand concentration increases

A

Increases binding of receptors
Increases saturation

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49
Q

The maximum response of a ligand is due to

A

number of receptors available and bound

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50
Q

At a given concentration (X) of saturation

A

high affinity receptors bind more messenger

going to plateau once they’ve all bound

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51
Q

At a given concentration (X) of competition

A

Descresing amount of receptors bound by endogenous ligand

Decreasing that response

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52
Q

Ligands can be

A

agonist or antagonist

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53
Q

What is receptor - competition?

A

Ability of an exogenous molecule to compete with the endogenous or native ligand for binding site

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54
Q

What is an agonist?

A

Ligand that mimics or increase the action of endogenous substance

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55
Q

What is an example of an agonist?

A

Nasal spray (phenylephrine)

Mimics E -> vasoconstriction and nasal hypo secretion

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56
Q

What is an antagonist?

A

Molecule binds receptor and inhibiting activation occuring

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57
Q

What is a beta-blocker?

A

Decreases heart rate, vasodilation causing decrease in blood pressure

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58
Q

What are antihistamines?

A

Inhibit histamine release by mast cells causing decrease in allergic response

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59
Q

What is the regulation of receptors via down regulation?

A

Decrease in overall number of cell receptors for a specific ligand

Usually due to chronic exposure to large amounts of ligand

Desensitization
DM II

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60
Q

What is the internalization of receptors via receptor-mediated endocytosis?

A

Prolonged exposure to agonists often results in endocytosis of receptors

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61
Q

How is DM II involved in regulation of receptors via down-regulation?

A

Glucose, cells get used to having it around so they down regulate glucose receptors. Person thinks they need more, eat more, more down regulation.

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62
Q

What is up regulation?

A

Cells increase numbers of receptors due to low amounts of ligand

Increases sensitivity

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63
Q

What is down regulation?

A

A decrease in the total number of target-cell receptors for a given messenger; may occur in response to chronic high extracellular concentration of the messenger

Decrease number of hormone receptors decreases sensitivity

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64
Q

What is the regulation of receptors via up regulation?

A

Cells increase number of receptors due to low amounts of ligand causing increase in sensitivity

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65
Q

What is regulation of receptors via down regulation?

A

Target cells lose receptors in response to the hormone

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66
Q

What does the sensitivity of target cells depend on?

A

Part on number of receptors
Factors that affect signal transcription or gene transcription

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67
Q

What are signal transduction pathways?

A

Specific sequences of events (steps) and chemical molecules involved in the pathway that respond to receptor activation

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68
Q

What are lipid soluble messengers?

A

Includes steroids, TH
Majority bind intracellularly on nuclear receptors
Slower but longer-lasting response
One receptor can impact multiple genes causing change in transcription activity

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69
Q

What are the components of signal transduction pathways?

A

Lipid-soluble messengers
Water-soluble messengers

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70
Q

What is receptor activation?

A

Plasma membrane receptors have a complex/ complicated system due to the multiple steps involved

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71
Q

What are the PM effects of receptor activation?

A

Permeability altered, transporter properties, and/or voltage shifts

72
Q

What are the potential cellular responses of receptor activation?

A

Metabolism altered, secretory activation, rate of proliferation & differentiation, contractility, etc

73
Q

What does an activated receptor do?

A

Increases or decreases gene activity

74
Q

What are exceptions to lipid soluble messengers?

A

Binds plasma membrane, bind inactive cytosolic receptors

75
Q

In lipid-soluble messengers, one receptor can impact multiple genes which

A

changes transcription activity

76
Q

What is the speed and response of lipid-soluble messengers?

A

Slower but longer-lasting response

77
Q

What is the first messenger?

A

Ligand in the extracellular fluid that binds to plasma membrane receptor

78
Q

What is the second messenger?

A

Intracellular molecule generated in response to 1st messenger

Ex.) cAMP, Ca 2+, IP3, DAG, etc

79
Q

What are protein kinases?

A

An enzyme that phosphorylates other proteins by transferring the high energy 3rd phosphate group from ATP

80
Q

What are activated proteins?

A

Transporters, metabolic enzymes, contractile proteins
Cells respond to 1st messenger

81
Q

Describe Water-soluble messengers

A

Water soluble ligands bind to extracellular receptors

Ex.) Polypeptide hormones, NTs, Paracrine, autocrine substances

82
Q

Water-Soluble messengers have a broad range of receptors that include

A

Ion channels, GPCRs, Receptors with intrinsic kinase activity, etc

Receptors activate intracellular signaling cascades that affect cell function

These receptors can (+) activate downstream mediators , which affect DNA transcription, but also have many other effects in the cell

Faster, but shorter-lasting response

83
Q

Describe the timing and response of water-soluble messengers

A

Faster but shorter-lasting response

84
Q

What is the classification of receptors based on?

A

Their locations and signal transduction pathways they use

85
Q

What are intracellular receptors function?

A

(Lipid soluble messengers)

Function in the nucleus as transcription factors or suppressors to alter the rate of transcription of particular genes

86
Q

What are plasma membrane receptor types?

A

Ligand gated ion channels

Function as enzymes, receptor tyrosine kinases

Bound to and activate cytoplasmic janus kinases

G protein couple receptors activate G proteins

87
Q

In signaling by receptors that are ligand-gated ion channels we find

A

Binding of ligand gated ion channels

Causes conformational change of receptor and opening or closing of channel through plasma membrane

Abundant in nervous and muscle tissues

Ions diffuse into/out of cell.
Ex. Na+, K+, Ca2+, Cl-

Often results in a change in the MP of a cell

88
Q

Where is signaling by receptors that are ligand gated ion channels abundant?

A

Nervous and muscle tissue

89
Q

In signaling by receptors that function as enzymes, some receptors have intrinsic enzyme activity such as?

A

Usually protein kinases that phosphorylate tyrosine residues
*receptor tyrosine kinases
Guanylyl cyclase which catalyzes cGMP is an exception

90
Q

What is the sequence of events of intrinsic enzyme binding

A

1st messenger binds tyrosine kinase receptor -> conformational change -> activation of enzymatic cytoplasmic receptor -> autophosphorylation of receptor of tyrosine residues -> phosphotyrosines become docking sites for cytoplasmic proteins -> bind and activate other proteins

91
Q

Signaling by receptors that function as enzymes causes what?

A

Cascade of events leading to activation of 1 or more signaling pathways & cytoplasmic proteins by phosphorylation

92
Q

What are growth factors (Gfs)?

A

Cell proliferation/differentiation

Without Gfs neurons will NOT grow

Presence /absense of Gfs can decide if cells are viable or not

93
Q

Signaling by receptors that interact with cytoplasmic janus kinases contain?

A

Several families of cytoplasmic protein kinases
-> non-receptor tyrosine kinases, SFKs (src), JAKs, etc

Ligand binds receptor that lacks intrinsic kinase activity

94
Q

How does the ligand bind to a receptor that lacks intrinsic kinase activity?

A

1st messenger -> conformational change -> (+) JAK -> targets protein phosphorylation -> (+) transcription factors -> new protein synthesis

95
Q

Cytokine signaling occurs via

A

receptors linked to JAKs

96
Q

What is signaling by G-protein coupled receptors?

A

Superfamily (largest) of cell-surface receptors
Encoded by more than 1000 genes
Involved in virtually all physiological processes

97
Q

What do GPCR signal transduction convert extracellular messages to?

A

Intracellular responses

98
Q

What is the role of G-protein coupled receptors?

A

Play a major role in sensory stimuli & processing

Vision, olfactory, gustation, nociception, etc

99
Q

AbNL GPCRs disorders include

A

Allergies, HTN, depression, obesity, CNS disorders

Over half of all medications are targeting GPCRs

Significant % of prescription medications directly or indirectly target GPCRs

100
Q

What is the structure of GPCRs?

A

Intracellular, peripheral protein complex of 3 subunits -> alpha, beta, & gamma

101
Q

What are the 3 subunits of GPCRs?

A

Alpha, beta, gamma

102
Q

What do the beta and gamma subunits do?

A

Anchor complex to plasma membrane, anchor alpha unit (dissociates)

May activate (stimulatory) or inhibit (inhibitory) (kinase activity)

103
Q

The alpha subunit of GPCRs can bind?

A

GDP and GTP

104
Q

What happens when GPCR alpha subunit binds to GTP?

A

Dissociates and couples to effector protein (ion channel or enzyme)

Structure almost always influences function

105
Q

In GPCRs the water soluble is binding, WHY?

A

Being transported through blood, which is 90% water. More efficient to have water soluble

106
Q

Messengers that are hydrophilic are

A

Metabolically efficient

107
Q

Messengers that are water fearing (lipid soluble) are

A

dependent on carrier protein

108
Q

What happens when the ligand binds to the GPCR?

A

Changes the receptor’s shape
Then activates an associated G-protein
Then activates effector proteins

Ex. Enzyme functions or ion channels
-Effect can either be (+) or (-)

109
Q

What is the G protein system function?

A

Serve as a switch (on or off) to couple a receptor to an ion channel or to an enzyme in the plasma membrane

110
Q

What are 2nd messenger systems (subfamilies) for GPCRs?

A

Cyclic AMP, IP3/DAG, Ca 2+, Arachidonic acid and Eicosanoids

1 receptor may be associated with more than or equal to 1 G protein type

G proteins may couple to multiple plasma membrane effector proteins

111
Q

What can GPCRs directly regulate?

A

Opening and closing of ion gated channels

112
Q

What are the common mechanisms by which receptor activation influences ion channels?

A

The ion channel is part of the receptor

A G protein directly gates the ion channel

A G protein gates the ion channel indirectly via production of a second messenger such as cAMP

113
Q

What is Adenylyl cyclase?

A

Changes cytosolic ATP to cyclic AMP in response to an extracellular signal (2nd messenger)

Effector protein of Gs (stimulatory)

114
Q

What is Gs?

A

Stimulates adenylyl cyclase, which increases levels of cAMP in the cell

(+) its effector protein (adenylyl cyclase) a PM protein

115
Q

What is cyclic AMP?

A

A second messenger derived from ATP and triggers specific cellular changes in metabolic regulation

116
Q

What does the 1st messenger in adenylyl cyclase and cyclic AMP do?

A

Epinephrine binds and (+) GPCR - Gs (stimulatory)

117
Q

What happens to cAMP action when broken down to AMP?

A

cAMP action halts

118
Q

What does altering the rate of 2nd messenger-mediated synthesis do?

A

Changes concentration of 1st messenger

Receptor numbers, etc

119
Q

Altering the rate of action of cAMP phosphodiesterase

Why are coffee & tea stimulants?

A

Caffeine and theophyllinee inhibit phosphodiesterase activity which prolongs cAMP activity

120
Q

What is cAMP phosphodiesterase?

A

An enzyme that breaks down cAMP halting the action of cAMP

121
Q

What is the intracellular action of cAMP?

A

cAMP binds and activates cAMP - PKAs (dependent protein kinase A)

122
Q

What happens when cAMP binds and activates cAMP PKAs (dependent protein kinase A)?

A

Phosphorylates various downstream targets

123
Q

What does epinephrine do within the intracellular action of cAMP?

A

Adipocytes to break down stored triglycerides which increases blood glucose

Liver for glycogenolysis & gluconeogenesis, anabolism

124
Q

What is glycogenolysis?

A

Breaks down glycogen to use parts to make glucose

125
Q

When does epinephrine increase?

A

When physically active or stressed

126
Q

Describe how there is a variety of cellular responses induced by cAMP?

A

Same 1st and 2nd messengers can have differing cellular responses

127
Q

In signal amplification, 1 molecule of 1st messenger can lead to as much as 1 M of final product. What are the advantages/disadvantages?

A

Advantage: Only a little produces a lot, sets off big cascade. Energy efficient.

Disadvantage: Huge intracellular response, innate dangers. Gets out of control.

But they’re the same.

This is how very low amounts of substances can have significant effects systemically

128
Q

Explain the differing effects & “types” of G proteins, how cAMP-PKAs pathways are involved

A

cAMP-PKAs can enter nucleus to alter gene expression
highly variable

129
Q

Explain the differing effects & “types” of G proteins
Do all GPCRs stimulate cAMP?

A

Not all GPCRs stimulate cAMP; some inhibit adenylyl cyclase

130
Q

Explain the differing effects & “types” of G proteins, explain Gi protein activation

A

Gi (inhibitory) protein activation -> decreases cAMP levels
Decreases the rate of phosphorylation of cytoplasmic proteins

131
Q

What is the control of ion channels by G proteins?

A

Ion channels themselves can be the “effector protein” for a G protein complex
With direct or indirect regulation

132
Q

If you have Gs then you have

A

Gi

133
Q

What is the direct regulation of ion channels of G protein

A

G protein channel interaction
No 2nd messenger involved

134
Q

What is the indirect regulation of ion channels by G proteins

A

Ex. PKA phosphorylates a plasma membrane ion channel causing opening of channel
2nd messengers utilized

135
Q

What does Gq protein activate?

A

Phospholipase C

136
Q

What happens when Gq protein activates phospholipase C?

A

Increases IP3 and DAG (diacyl glycerol) synthesis

137
Q

What do IP3 and DAG do?

A

For together to activate enzymes which increase intracellular calcium levels
2nd messengers

138
Q

What is phospholipase C?

A

plasma membrane effector enzyme
phosphatidylinositol bisphosphate (PIP2) (PM phospholipid)

139
Q

What is diacylglycerol (DAG)?

A

A second messenger produced by the cleavage of a certain kind of phospholipid in the plasma membrane

140
Q

What is inositol triphosphate (IP3)?

A

A second messenger that functions as an intermediate between certain signaling molecules and a subsequent second messenger, Ca2+, by causing a rise in cytoplasmic Ca2+ concentration

141
Q

PLC is what?

A

A plasma membrane effector enzyme

142
Q

DAG and IP3 are what?

A

Both 2nd messengers
DAG -> protein kinase C

143
Q

What does Gq (G protein) activate?

A

PLC
PLC is a PM effector enzyme

144
Q

What does DAG activate?

A

Protein kinase C

145
Q

What does cytosolic IP3 bind to?

A

Receptors located on endoplasmic reticulum

146
Q

Within inositol triphosphate, what happens when cytosolic IP3 binds to receptors located on endoplasmic reticulum?

A

Ligand gated Ca2+ channels open when bound to IP3
which causes increase in cytosolic Ca2+ levels
Sequence of events is dependent on specific pathway

147
Q

How does Ca2+ behave as a 2nd messenger?

A

Can be increased or decreased causing the cytosol to elicit a cellular response

148
Q

Normally cytosolic Ca2+ levels are

A

Extremely low
Maintained via active transport pumps in plasma membrane and organelles

149
Q

What does the large electrochemical gradient favor in regard to Ca2+ as a second messenger?

A

Diffusion of Ca2+ into the cytosol

150
Q

A stimulus to the cell can alter

A

ICF Ca2+ levels

Directly opens channel to influx Ca2+ levels
Or indirectly allows release of Ca2+ to cytoplasm

151
Q

Altering Ca2+ intracellular levels, explain how electrical stimuli can open plasma membrane Ca2+ channels

A

Open Ca regulated ion gates on organelles
Ca2+ induced - Ca2+ release
Fuels muscle contraction

152
Q

What does Ca2+ have the ability to do?

A

Ca2+ has the ability to bind cytosolic proteins

153
Q

Ca2+ has the ability to bind cytosolic proteins causing

A

conformational change causing activation of calcium/troponin for muscle contraction

The conformation change alters affinity

154
Q

How is Calmodulin involved in altering Ca2+ intracellular levels?

A

Calmodulin binding is found in all cells

Involved in muscle contraction
(+) or (-) of calmodulin-dependent protein kinases leads via phosphorylation to either activate or inhibit cellular protein responses to 1st messenger

155
Q

Explain Calcium as a second messenger, in which stimulation of a cell leads to an increase in cytosolic Ca 2+ concentration

A

1st. Receptor activation
Plasma membrane Ca2+ channels open in response to a first messenger; the receptor itself may contain the channel, or the receptor may activate a G protein that opens the channel via a second messenger
Then
Ca2+ is released from the endoplasmic reticulum; this is typically mediated by IP3
Then
Active Ca2+ transport out of the cell is inhibited by a second messenger
2. Opening of a voltage-gated Ca2+ channel

156
Q

Explain calcium as a second messenger by which an increase in cytosolic Ca2+ concentration induces the cell’s responses

A
  1. Ca2+ binds to calmodulin. On binding Ca2+, the calmodulin changes shape and becomes activated, which allows it to activate or inhibit a large variety of enzymes and other proteins. many of these enzymes are protein kinases
  2. Ca2+ combines with Ca2+ binding proteins other than calmodulin, altering their functions
157
Q

What is Arachidonic acid?

A

Polyunsaturated fatty acid of the plasma membrane phospholipids

Lipid component of plasma membrane

158
Q

What are Eicosanoids?

A

Produced from Arachidonic acid in many cell types for many reasons

Liberate arachnidoic acids from plasma membrane

159
Q

In arachidonic acid and eicosanoids what stimulus binds receptor?

A

Neurotransmitters, hormone, durg
-> PLA2 phospholipase activation
-> Arachidonic acid

Liberates arachidonic acid

160
Q

What are the types of eicosanoids?

A

Cyclic endoperoxides
Pls (prostaglandins)
TXAs (thromboxanes)
LTs (leukotrienes)

161
Q

What does PLA2 cleave?

A

arachidonic acid from the plasma membrane

162
Q

What are the two metabolic pathways of PLA2?

A

Cyclooxygenase (COX) pathway
Lipoxygenase pathway

163
Q

What are PGs (part of the COX pathway)?

A

Prostalgandins

PGA, PGE

Pain, fever, blood clotting, inflammation

164
Q

What are TXAs (part of the COX pathway) ?

A

Hemostasis

Aspirin, NSAIDs block cox
Aspirin -> stroke, inhibits blood clotting, decrease risk of forming clots

165
Q

What is cyclooxyrgenase (COX)?

A

Type of enzyme that helps encourage the production of prostaglandins (PGs)

166
Q

What is the lipoxygenase pathway?

A

Pathway involved in converting AA into leukotrienes and lipoxins

LTs -> allergic response, inflammation

167
Q

When steroids block PLA2 what happens?

A

Block all eicosanoid synthesis

decrease inflammation and allergic responses

168
Q

Why are people advised to avoid taking aspirin or other NSAIDs prior to surgical procedure?

A

Going to really bleed

169
Q

What do NSAIDs function as

A

analgesics

170
Q

How NSAIDs work?

A

These agents decrease pain and inflammation by inhibiting action of cyclooxygenase

171
Q

What do analgesics do?

A

Decrease perception of pain

172
Q

What does anesthesia do?

A

Put someone in an unconscious state

173
Q

What does an epidural do?

A

Inhibit ability to sense pain

174
Q

What are amnesiacs?

A

Inhibiting ability to have short term recall of events

175
Q

How are signal transduction pathways regulated via negative feedback HC?

A

Receptor activation must stop

176
Q

Signal transduction pathways are often regulated how?

A

Via negative feedback HC

177
Q

What happens when receptor activation stops in signal transduction pathways?

A

Causes decrease in 1st messenger amount binding to receptor

Leads to enzyme degradation, diffusion, uptake by neighboring cells

Causes decrease in cytosolic 2nd messenger levels

178
Q

How do receptor structural changes occur in signal transduction pathways

A

Decreasing receptor affinity for 1st messenger

Phosphorylation halts further G protein binding

Internalization via receptor mediated endocytosis of receptor / 1st messenger complex

179
Q

Why is receptor activation stopping and receptor structural changes important?

A

Critical to prevent overstimulation of a cell by a messenger and the detrimental effects that could occur as a result

Affinity to bind to a different protein occurs

180
Q

Give an enzymatic breakdown example

A

Adenylyl cyclase -> change in cytosolic ATP to cAMP (2nd messenger)

Vertebrate Physiology (5 decks)

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