Themes 4 + 5 Flashcards

Homeostasis and Environmental Adaptation & The Nervous System

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1
Q

Who defined homeostasis? (2 ppl)

A

Claude Bernard, Walter Cannon

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2
Q

Homeostasis

A

Process of maintaining a relatively stable internal environment despite changes in the external surroundings.

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3
Q

2 types of Homeostatis

A

Conformers and Regulators

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4
Q

Conformers

A

maintain same fluid composition as environment

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5
Q

Which is energetically cheaper? Conformers or Regulators?

A

Conformers

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6
Q

Regulators

A

internal composition of fluids different from environment

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7
Q

Thermogenesis

A

Generation of thermal energy in an organism

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8
Q

4 types of Thermogenesis?

A

Homeotherms
Poikilotherms
Endotherms
Ectotherms

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9
Q

Homeotherms

A

organisms that maintain a stable internal body temperature regardless of external influence.

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10
Q

Poikilotherm

A

organisms whose internal temperature varies considerably.

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11
Q

Which type(s) of Thermogenesis depends on ambient temperature?

A

Poikilotherm, Ectotherm

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12
Q

Endotherms

A

heat primarily generated from internal metabolic processes

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13
Q

Ectotherms

A

control body temperature through external means;

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14
Q

Example of an Ectotherm?

A

Reptiles; regulate body temperature by basking in the sun.

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15
Q

Can Poikilotherms be Ectotherms?

A

Yes, meaning their temperature varies over a wider range than homeotherms.

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16
Q

Are physiological functions constant for very long?

A

No

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17
Q

After a meal the level of glucose in your blood can…

A

increase rapidly

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18
Q

If you skip a meal, your blood sugar level may…

A

drop slightly.

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19
Q

4 Variables of Homeostatic Control Systems:

A

Set point
Sensor
Integrator
Effector

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20
Q

Set Point

A

normal value for controlled variable

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21
Q

Sensor

A

monitors particular variable

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22
Q

Integrator

A

compares signals from the sensor to set point

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23
Q

Effector

A

compensates for deviations between actual value and set point.

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24
Q

Feedback

A

a fundamental feature of homeostasis; major way disturbances are minimized.

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25
Q

Negative Feedback

A

variable being regulated bring about response that moves the variable in the opposite direction.

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26
Q

Positive Feedback

A

Accelerates a process;
Explosive system (rapid)
used in Birth + effect of estrogens in ovulation.

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27
Q

Where does negative feedback occur?

A

organ
cellular
molecular levels

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28
Q

What type of Feedback prevents overcompensation?

A

negative feedback

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29
Q

Another name for Positive feedback?

A

Supra-physiological responses

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30
Q

Feedforward Regulation

A

Animal’s body begins preparing for a change in some variable before it occurs.
Speeds up homeostatic responses and minimizes derivation from the set point.

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31
Q

What type of regulation is a result from or is modified by learning?

A

Feedforward Regulation

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32
Q

What type of Regulation is Anticipatory?

A

Feedforward Regulation

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33
Q

Pavlov ‘s experiment demonstrated the relationship between what 2 things?

A

Learning and Feedforward Processes

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34
Q

What chemical communication between cells is essential to homeostasis? (3)

A

paracrine signals
neurotransmitters
hormones

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35
Q

The Nervous system

A

a network of specialed cell that coordinate functions and transmit signals between different organs.

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36
Q

What System regulates internal processes-all while maintaining homeostasis?

A

The nervous system

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37
Q

2 Parts of the Nervous system?

A

Central Nervous System (CNS)

Peripheral Nervous System (PNS)

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38
Q

Central Nervous System organs?

A

Brain and spinal cord

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39
Q

Peripheral nervous system is composed of ?

A

all neurons and projections of their plasma membranes that are outside of the CNS.

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40
Q

T or F - In Certain invertebrates with a simple nervous system, the distinction between CNS and PNS is less clear or not present.

A

True

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41
Q

Composition of the CNS? (matters)

A

Grey Matter and White Matter

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42
Q

Grey Matter

A

is the major component of the CNS

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43
Q

What does Grey Matter consist of ?

A

Neuronal Cell bodies, dendrites, and axons
Glial cells
Capillaries

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44
Q

the grey-brown color in Grey matter comes from what?

A

Capillary blood vessels and neuronal cell bodies.

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45
Q

White matter

A

mostly contains myelinated axon tracts

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46
Q

What does the white color in White matter come from?

A

whiteness of myelin.

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47
Q

Myelin

A

an electrically insulating material that forms a layer around axons.

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48
Q

What is Myelin composed of?

A

80% lipids(primarily glycolipids galactocerebroside)

20% protein

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49
Q

What is the protein portion of Myelin is made up of?

A

Myelin basic protein (MBP)
Myelin oligodendrocyte glycoprotein (MOG)
Proteolipid Protein (PLP)

50
Q

What is the lipid portion of Myelin is made up of ?

A

glycolipids galactocerebroside

51
Q

Neurons

A

cells that send and receive electrical and chemical signals.

52
Q

What type of animal does not have neurons?

A

sponges

53
Q

The number of Neurons present is a function of what?

A

size and behavioural complexity

54
Q

Transmission of Electrical and chemical signals occur in the form of?

A

action potentials

55
Q

action potentials

A

a short lasting event in which the electrical voltage of the cell memebrane rapidly rises and falls. (consistent trajectory)

56
Q

Cells that action potentials occur in:

A

excitable cells

57
Q

excitable cells include:

A

neurons, muscle cells, endocrine cells, as well as some plant cells.

58
Q

What plays a central role in cell-to-cell communication?

A

action potentials

59
Q

“nerve impulse” or “spike” or “fire”

A

action potential

60
Q

In muscle cells, action potentials are the first step in a chain leading to:

A

contraction of muscles

61
Q

In B-cells of the pancreas action potentials lead to:

A

release of insulin

62
Q

Neuron Structure includes:

A

Soma
Dendrites
Axons

63
Q

Soma

A

Cell body; contains nucleus and organelles

64
Q

Dendrites

A

branched projections of a neuron that conduct the electrochemical stimulation received from other cells. (RECEIVE SIGNALS)

65
Q

Axons -

A

Long slender projection of neurons; Conducts electrical impulses away from the soma. (SENDS SIGNALS)

66
Q

Axons are distinguished from dendrites by:

A

Length : dendrites are restricted to a small region around the cell body, while axons can be much longer
Function: dendrites usually receive signals while axons usually transmit them.

67
Q

Synapses

A

electrical stimulation transmitted onto dendrites by upstream neurons; located throughout the dendrite arbor.

68
Q

Another name for Glial cells:

A

Neuroglia

69
Q

Glial Cells

A

non nervous cells; commonly known as the glue of the Nervous system.

70
Q

In the human brain, what is the ratio of glia:neuron?

A

1:1

71
Q

In cerebral gray matter, what is the ratio of glia:neuron?

A

3:2

72
Q

What are the 6 types of Glial cells?

A
SOMEAS
Schwann cells
Oligodendrocytes
Microglia
Ependymal cells
Astrocytes
Satellite cells
73
Q

Astrocytes

A

“Star” shaped

  1. provision of nutrients
  2. maintenance of extracellular ion balance
  3. repair and scarring process of the brain and spinal cord
    * 4.biochemical support of endothelial cells which form the blood-Brain barrier
74
Q

Another name for Astrocyte?

A

Astroglia

75
Q

Blood-Brain-Barrier (BBB)

A

a separation between the circulating blood and brain extracellular fluid.
Consists fo tight junctions around the capillaries that do not exist in normal circulation.

76
Q

Functions of the Blood brain barrier?

A
  1. Restrict the diffusion of microscopic objects (tight junctions)
  2. Actively transport metabolic products such as glucose.
77
Q

Microglia

A

Macrophages of the brain and spinal cord;
Main active immune defence
Scavenges for damaged neurons, plaques, and infectious agents.

78
Q

The main active immune defence of the CNS?

A

Microglia

79
Q

~20% of all glial cells are?

A

Microglia

80
Q

Ependymal Cells

A

thin epithelial membrane lining the ventricular system of the brain and the spinal cord.
Involved in the function of cerebrospinal fluid.(CSF)

81
Q

What is the Function of Ependymal Glial Cells?

A

production of cerebrospinal fluid.

82
Q

Cerebrospinal Fluid (CNS)

A

clear colorless bodily fluid produced by ependymal cells of the brain.
Fill the ventricles and cisterns of the brain and the central canal of the spinal cord.

83
Q

Functions of the Cerebrospinal Fluid (CNS)

A
  1. It acts as a cushion or buffer for the cortex
  2. Provide Mechanical or immunological protection to the brain
  3. play a vital function in regulation of cerebral blood flow.
84
Q

Oligodendrocytes

A

Insulate axons in the CNS, mainly in the brain and spinal cord
*relatively few branches

85
Q

another name for Oligodendrocytes

A

Oligodendroglia

86
Q

Schwann Cell

A

the principal glia cells of the CNS; Wrap around the axons of motor and sensory neurons to form the myelin sheath.

87
Q

What is the principal Glia cell of the PNS?

A

Schwann Cell

88
Q

Myelination

A

The production of the myelin sheath.

89
Q

What cells myelinate the PNS?

A

Schwann cells

90
Q

What cell myelinate the CNS?

A

Oligodendrocytes

91
Q

During what week of fetal development does myelination begin ?

A

14th week

92
Q

T or F: During infancy myelination occurs slowly and does not stop until the adolescent stages of life

A

false : occurs rapidly.

During infancy myelination occurs RAPIDLY and does not stop until the adolescent stages of life

93
Q

Children under the age of two should receive a diet higher in _____ ?

A

Fats

94
Q

Myelin sheath is interrupted by:

A

Nodes of Ranvier

95
Q

Nodes of Ranvier

A

uninsulated gap (~1um) formed between the myelin sheaths;

96
Q

Nodes of Ranvier are unmyelinated to promote…

A

exchange of ions faster.

97
Q

Satellite glial cells (SGCs)

A

line the exterior surface of neurons in the PNS.

98
Q

Which two types of Glial cells share similar embryolgical origin of the neural crest of an embryo in the PNS?

A

Schwann cells, Satellite glial cells (S&S)

99
Q

Function of the Satellite Glial Cells:

A
  1. Control over the microenvironment of sympathetic ganglia
    * thought to be similar to Astrocytes of CNS
  2. supply nutrients to the surrounding neurons and also supply structural function
  3. act as protective cushioning cells
  4. Express a variety of receptors that allows for a range of interactions with neuro-active signalling chemicals.
100
Q

What cell of the PNS shares a similar role to Astrocytes in the CNS?

A

SGC - satellite glial cells

101
Q

3 main types of Neurons?

A
  1. Sensory Neurons
  2. Motor Neurons
  3. Interneurons (or association Neurons)
102
Q

Sensory Neurons

A

Afferents - detect information from the outside world or internal body conditions and transmits to the CNS
Usually a large axon that bypasses the cell body and goes directly to CNS
*automatic - not controlled
X==={o}====8

103
Q

What type of Neuron is Afferent?

A

Sensory Neurons

104
Q

What type of Neuron is Automatic; Involuntary?

A

Sensory Neurons

105
Q

Which type of Neuron has a cell body that has a bypassing axon?

A

Sensory Neurons

106
Q

Motor Neurons

A
  • Efferent* - sends signals away from CNS to elicit response.
  • controlled; voluntary

X{o}=======8

107
Q

Afferent

A

brings in;

108
Q

Efferent

A

sends away

109
Q

Which type of Neuron is Voluntary; controlled?

A

Motor neurons

110
Q

Which type of Neuron has the soma located within the network of dendrites ?

A

Motor neuron

111
Q

Interneurons

A

form interconnections between other neurons in the CNS.
tend to have many dendrites
axons are typically short and highly branched allowing to form complex connections with other cells.

112
Q

What type of Neuron has many dendrites?

A

Interneuron

113
Q

What type of Neuron typically has short, highly branched axons?

A

interneuron

114
Q

another name for interneuron

A

Association Neuron

115
Q

Reflex Circuit

A

a series of connections where neurons transmit information to each other.

116
Q

A Reflex arc

A

a simple circuit; allows an organism to repsond rapidly to inputs from sensory neurons and consists of only a FEW neurons.

117
Q

T or F: many neurons are involved in a reflex arc.

A

False; few are involved.

118
Q

What are the oldest and most importnat features of the nervous system? (they exist in simple animals as well as complex)

A

Reflexes

119
Q

Pathway of a Reflex Circuit:

A
  1. stimulus from sensory neurons
  2. sent to CNS and there is little to no interpretation
  3. signal is then transmitted to motor neurons
  4. Reflex action
120
Q

Infant primates have a strong grasp that help them hold onto their others as they move, this is an example of?

A

reflex arcs