Chapter 6: Communication, Integration, and Homeostasis Flashcards

1
Q

what are the two types of physiological signals for cell to cell communication?

A
  • electrical

* chemical

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2
Q

what are the methods of cell to cell communication?

A
  1. local communication

2. long distance communication

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3
Q

what does local communication consist of?

A
  • gap junctions
  • contact-dependent signals
  • paracrine signals
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4
Q

what does long distance communication consist of?

A
  • passing along neurons

* chemical messengers transported through the blood

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5
Q
  • cytoplasmic link between adjacent cells
  • involve connexin proteins
  • can function in synchronizing communication
A

gap junctions

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6
Q

where are gap junctions found?

A
  • heart muscle
  • smooth muscle
  • some glands
  • some neurons in -the brain
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7
Q
  • A surface molecule on one cell binds a membrane protein on another.
  • cell adhesion molecules (CAM’s)
  • Play a role in the immune system as well as growth and development
A

contact-dependent signals

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8
Q

Chemicals that communicate with neighboring cells (must be close enough that once secreted into ECF it can reach the target cell by simple diffusion

A

paracrine signals

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9
Q

what are paracrine examples?

A
  • Eicosanoids lipid derived signal molecules

- Cytokines peptides function in coordinating the body’s defense against infections

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10
Q

what do autocrine signals act on?

A

act on the cell that secreted it

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11
Q

what are hormones secreted by?

A

endocrine system

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12
Q

chemicals secreted into the interstitial fluid, where they diffuse into the blood and are distributed all over the body

A

hormones

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13
Q

which cells can respond to hormones?

A

Only cells possessing receptors specific for the hormone can respond (target cells)

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14
Q

this system is a combination of chemical and electrical signals

A

nervous system

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15
Q

how do the chemical and electrical signals of the nervous system work?

A
  • Electrical signals travel down neurons

- Chemical signals secreted by neurons are neurocrine molecules

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16
Q

diffuse across narrow space to target cell (rapid onset effect)

A

neurotransmitter

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17
Q

signal acts as a paracrine signal

A

neuromodulator

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18
Q

chemicals
released by neurons into the blood
for action at distant targets

A

neurohormone

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19
Q

what do signal pathways include?

A
  • ligand (1st messenger) binding receptor protein
  • receptor activation
  • activation of intracellular signal molecules
  • response of cell by protein modification or synthesis
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20
Q

transmit their signals by binding to target cell receptors located either on the plasma membrane, in the cytosol, or in the nucleus.

A

chemical messengers

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21
Q

what is the location of binding dependent on?

A
  • dependent on the properties of the molecule
    • lipophilic molecules
    • lipophobic molecules
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22
Q

receptors are cytosolic or nuclear (slower response)

A

lipophilic molecules

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23
Q

receptors on the cell membrane (rapid response)

A

lipophobic molecules

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24
Q

what does intracellular signal receptors involve?

A
  • receptor in cytosol
  • receptor in nucleus
  • lipophilic signal molecules
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25
Q
  • diffuse through cell membrane
  • bind to cytosolic or nuclear receptor
  • triggers slower responses related to changes in gene activity
A

lipophilic signal molecules

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26
Q

what does cell membrane receptors involve?

A
  • extracellular signal molecule binds to cell membrane receptor
  • binding triggers rapid cellular responses
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27
Q

occurs when extracellular signal molecules activate receptors that alter intracellular molecules to create a response

A

signal transduction

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28
Q

what are the steps of signal transduction?

A
  1. first messenger binds receptor
  2. Activated receptor turns on associated protein which starts intracellular cascade of secondary messengers
  3. Second messenger molecules
  4. The last second messenger acts on the intracellular target to create a response
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29
Q

what proteins do activated receptors turn on?

A
  • activated protein kinases

- amplifier enzymes that create intracellular second messengers

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30
Q

what do second messenger molecules do?

A
  • open and close ion channels
  • increase intracellular calcium
  • change enzyme activity (kinases & phosphatases)
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31
Q

what do signal transduction pathways form?

A

a cascade

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32
Q

occurs when the receptor-ligand complex activates an amplifier enzyme

A

signal amplification

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33
Q

allows a small amount of

signal to have a large effect

A

signal amplification

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34
Q

what are some second messengers?

A
  • cAMP
  • cGMP
  • IP3
  • DAG
  • ca2+
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35
Q

what are the nucleotide second messengers?

A
  • cAMP

- cGMP

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36
Q

what are the lipid derived second messengers?

A
  • IP3

- DAG

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37
Q

what is the ion second messenger?

A

Ca2+

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38
Q
  • activates protein kinases (PKA)
  • binds to ion channels
  • phosphorylates proteins
  • alters channel opening
  • made from ATP
A

cAMP

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39
Q
  • made from GTP
  • activates protein kinases (PKG)
  • phosphorylates proteins
A

cGMP

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40
Q
  • made from membrane phospholipids
  • releases Ca2+ from intracellular stores
  • alters enzyme activity
A

IP3

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41
Q
  • made from membrane phospholipids
  • activates protein kinase C
  • phosphorylates proteins
A

DAG

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42
Q
  • binds to calmodulin & other proteins

- alters enzyme activity; exocytosis, muscle contraction, cytoskeleton movement, channel opening

A

Ca2+

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43
Q

what are the four major types of membrane receptors?

A
  1. receptor channels (ligand gated)
  2. G protein coupled receptors
  3. receptor enzymes
  4. integrin receptor
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44
Q

which membrane receptors are catalytic receptors?

A
  • receptor-enzyme

- integrin receptor

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45
Q

Ligand binding
opens or closes
the channel

A

receptor channel

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46
Q

Ligand binding to a G protein–
coupled receptor opens an ion
channel or alters enzyme activity

A

G protein–coupled receptor

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47
Q

Ligand binding to a
receptor-enzyme activates
an intracellular enzyme

A

Receptor-enzyme

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48
Q

Ligand binding to integrin
receptors alters enzymes
or the cytoskeleton

A

integrin-receptor

49
Q

initiate the most rapid intracellular responses.

A

receptor channels

50
Q

what are the kind of receptor-channels?

A
  • simple ligand-gated ion channels
    • non-receptor linked ion channels
      • voltage gated channels
      • mechanically gated channels
51
Q

open and close due to membrane potential

A

Voltage-gated channels

52
Q

open with pressure or stretch of membrane

A

mechanically gated channels

53
Q

Large membrane protein with a transducer molecule (G protein) attached to the cytoplasmic tail

A

G protein-coupled receptors (GPCRs)

54
Q

what are the ligands that bind with GPCRs?

A
  • neurotransmitters
  • hormones
  • growth factors
  • olfactory molecules
  • visual pigments
55
Q

what happens when GPCRs bind guanosine nuecleotides?

A
  • inactive when GDP bound

- active when GTP bound

56
Q

opens ion channels

A

active G protein

57
Q

what alters the enzyme activity of the cytoplasmic side of the cell?

A
  • GPCR-cAMP

- GPCR-phospholipase C

58
Q

receptor region on ECF side and enzyme region ICF side of the same protein

A

receptor-enzymes

59
Q

what can the enzyme portion be of receptor-enzymes?

A
  • kinases (tyrosine kinase)

- guanylyl cyclase

60
Q

the amplifier enzyme that produces cyclic GMP from GTP

A

guanylyl cyclase

61
Q

where is the enzyme portion of receptor enzymes?

A

on the intracellular side

62
Q

What is an example of a receptor enzyme on the intracellular side?

A

JAK kinase

63
Q

what is the process of receptor enzymes?

A
  • signal molecule binds to surface receptor
  • tyrosine kinase o cytoplasmic side
  • phosphorylated protein
64
Q
  • membrane spanning proteins

- transfer information into the cell

A

integrin (cell-matrix junction) receptors

65
Q

what can integrins do on the extracellular side of the cell?

A

these proteins can bind to proteins of the extracellular matrix or to ligand (ex. antibodies)

66
Q

what can integrins do inside the cell?

A

activate enzymes or can change the organization of the cytoskeleton

67
Q

what are integrin receptors involved in?

A
  • wound repair
  • cell adhesion
  • blood clotting
  • cell movement during development
68
Q

what does the magnitude of a target cell’s response depend on?

A
  1. the affinity of the receptor for the messenger
  2. the number of receptors
  3. the messenger’s concentration
69
Q

what does specificity of receptors allow for?

A

generally allows bind by only one messenger or a class of messengers

70
Q

what is an example of the specificity of receptors?

A
  • *Norepinephrine and epinephrine are both specific for adrenergic receptors)
    • α isoform higher affinity for norepinephrine
    • β isoform higher affinity for epinephrine
71
Q

ligands that bind to receptors and produce a biological response

A

agonist

72
Q
  • ligands that bind to receptors but do not produce a response
  • blocks receptor activity
A

antagonist

73
Q
  • an opioid agonist used in pain treatment

- binds to opioid receptors in spinal cord and brain to block pain

A

morphine

74
Q

an opioid antagonist that binds opioid receptors with more than 10 times the affinity of morphine, reversing the effects on users

A

naloxone

75
Q

a decrease in the number of receptors, when cells are exposed to high messenger concentrations for prolonged period

A

down-regulation

76
Q

how is down regulation achieved?

A
  • remove through endocytosis
  • Desensitize through binding of chemical modulator
  • drug tolerance
77
Q

an increase in the number of receptors compared to “normal” conditions, when cells are exposed to low messenger concentrations for prolonged period

A

up-regulation

78
Q

what can go wrong with signal transduction?

A
  • genetically inherited abnormal receptors

- toxins affecting signal pathways

79
Q
  • shortens half life of receptpr

- results in congenital diabetes insipidus

A

vasopressin receptor (X-linked defect)

80
Q
  • blocks enzyme activity of G proteins
  • cell keeps making cAMP
  • results in ions being secreted into lumen of intestine, causing massive diarrhea
A

cholera toxin

81
Q
  • father of american physiology

* described properties of homeostatic control systems

A

walter cannon

82
Q

what did walter mention say about homeostatic control systems?

A
  1. nervous regulation of internal environment
  2. tonic control
  3. antagonistic control
  4. one chemical signal can have different effects in different tissues
83
Q

what does nervous regulation of internal environment regulate?

A
  • regulates parameters
    • blood volume
    • blood osmolarity
    • blood pressure
    • body temperature
84
Q
  • the degree to which something is turned on or off, like volume on a radio
  • the signal is always present but changes in intensity
A

tonic control

85
Q

*factors that have opposing effects
*Insulin (decreases), glucagon (increases)
*uses different signals to
send a parameter in opposite directions

A

antagonistic control

86
Q

as we see with paracrine and autocrine signals are isolated changes in tissues and cells

A

local control

87
Q

what are the reflex pathways?

A
  • local control

- long distance control

88
Q

uses complicated reflex control pathways and uses both nervous and endocrine systems

A

long distance control

89
Q
  • is a stimulus (carbon dioxide concentration, blood pressure, light)
  • sensor have a threshold stimulus to set response in motion
  • afferent signal
A

input

90
Q

what are the different input signals?

A
  • If neural input signal is electrical and chemical transmitted by a sensory neuron.
  • If endocrine there is no input pathway and the stimulus acts directly on the endocrine cell
91
Q

what are the two categories of receptors?

A
  • cell membrane or intracellular receptor proteins

- sensors: specialized cells or structures that convert various stimuli into electrical signals

92
Q

what are the two categories of sensors/specialized cells?

A
  • central receptors

- peripheral receptors

93
Q

comparison of signal to set point

A

integration center

94
Q

where is the neural reflexes integration center?

A

in the CNS

95
Q

where is the endocrine reflexes integration center?

A

endocrine cell

96
Q
  • efferent signal
  • electrical and/or chemical
  • travels to target (effector) tissue or cell
A

output

97
Q

What are some neural targets?

A

muscle, exocrine and endocrine glands, adipose tissue

98
Q

What are some endocrine targets?

A

cells with the appropriate receptor for the hormone

99
Q

what are the types of responses?

A
  • cellular response
  • tissue or organ response
  • systemic response
100
Q

smooth muscle contraction after excited by neurotransmitter

A

cellular response

101
Q

decreases blood flow through blood vesse

A

tissue or organ response

102
Q

increase blood pressure

A

systemic response

103
Q

what make up physiological reflex pathways?

A

nervous and endocrine systems

104
Q

how do the nervous and endocrine systems work together?

A

work as a continuum rather than as discrete control systems

105
Q

what is the specificity of a neural reflex?

A

each neuron terminates on a single target cell or on a limited number of adjacent target cells

106
Q

what is the nature of the signal of a neural reflex?

A

electrical signal that passes through neuron, then chemical neurotransmitters that carry the signal from cell to cell

107
Q

what is the speed of a neural reflex?

A

very rapid

108
Q

what is the duration of action of a neural reflex?

A

usually very shot; responses of longer duration are mediated by neuromodulators

109
Q

what is the coding for stimulus intensity of a neural reflex?

A

each signal is identical in strength; stimulus intensity is correlated with increased frequency of signaling

110
Q

what is the specificity for endocrine reflexes?

A
  • most cells of the body are exposed to a hormone

* the response depends on which cells have receptors for the hormone

111
Q

what is the nature of the signal for endocrine reflexes?

A

chemical signals secreted in the blood for distribution throughout the body

112
Q

what is the speed on the endocrine reflex?

A

distribution of the signal and onset of action are much slower than in neural responses

113
Q

what is the duration of action for endocrine reflexes?

A

responses usually last longer than neural responses

114
Q

what is the coding for stimulus intensity for endocrine reflexes?

A

stimulus intensity is correlated with amount of hormone secreted

115
Q

hormones get secreted by endocrine glands into the bloodstream and……..

A

travel to all cells but elicit responses only in cells with specific receptors for that hormone

116
Q

an increase in receptor number on the surface of a cell membrane…….

A

makes the cell more sensitive to the signal molecules

117
Q

which of the following is the correct sequence for G protein coupled signal transduction?

A

ligand –> GPCR –> G protein –> adenylyl cyclase –> protein kinase –> tissue response

118
Q

ibuprofen is a non-steroidal anti-inflammatory drug (NSAID) that prevents inflammation by inhibiting…….

A

cyclooxygenase (COX)

119
Q

Norepinephrine and epinephrine both have specificity for alpha adrenergic receptors but norepinephrine has a higher affinity for the receptor. Epinephrine is there _______ of norepinephrine

A

an agonist and a competitor