Lecture 2 Flashcards
(114 cards)
1
Q
Your mental experiences depend on what?
A
Activity of a huge number of separate but interconnected cells.
2
Q
What kinds of cells comprise the human nervous system?
A
Neurons
Glia
3
Q
The human brain contains approximately how many neurons?
A
86 billion individual neurons
4
Q
What are the structures of an animal cell?
A
Membrane Nucleus Mitochondria Ribosomes Endoplasmic Reticulum
5
Q
What structre seperates the inside of the cell from the outside environment?
A
Membrane
6
Q
What structure contains the chromosomes?
A
Nucleus
7
Q
What structure performs metabolic activities and provides energe that the cells require?
A
Mitochondrion
8
Q
What are the sites at which the cell synthesizes new protein molecules?
A
Ribosomes
9
Q
What structure is a network of thin tubes that transports newly synthesized proteins to their location?
A
Endoplasmic Reticulum (ER)
10
Q
How are neuron cells different from other cells in the body?
A
They have a distinctive shape
11
Q
What type of neuron has it’s soma in the spinal cord?
A
Motor Neuron
12
Q
What type of neuron recives excitation from other neurons?
A
Motor Neuron
13
Q
What type of neuron conducts impulses along its axon to a muscle or gland?
A
Motor Neuron
14
Q
What type of neuron is specialized at one end to be highly sensitive to a particular type of stimulation?
A
Sensory Neuron
15
Q
What are the components of all neurons?
A
Dendrites
Soma/Cell body
Axon
Presynaptic Terminals
16
Q
What are branching fibers that have a surface that is lined with synaptic receptors responsible for bringing information into the neuron?
A
Dendrites
17
Q
What is the function of dedritic spines?
A
Increase surface area of dendrite
18
Q
The greater the surface area of the dendrite, the more what it receives?
A
Information
19
Q
Where is the nucleus, mitochondria and ribosomes contained?
A
Cell Body/Soma
20
Q
What is the responsibility of the cell body/soma?
A
Metabolic work in the neuron
21
Q
The cell body/soma is covered with what?
A
Synapses on it’s surface
22
Q
What is an axon?
A
Thin fiber of a neuron
23
Q
What does an axon do?
A
Transmits nerve impulses toward other neurons, organs or muscle.
24
Q
Axons may have what?
A
Myelin Sheath
25
What is a myelin sheath?
Insulating material around axons
26
What is the nodes of ranvier?
Interruptions in the myelin sheaths
27
What are presynaptic terminals?
End points of an axon that release chemicals to communicate with other neurons
28
What axon brings information INTO structure?
Affferent Axon
29
What axon carries information AWAY from a structure?
Efferent Axon
30
What are the types of neuorns whose dendrites and axons are completely contained within a single structure?
Interneurons or Intrinsic Neurons
31
Neurons vary in what?
Size
Shape
Function
32
The shape of a neuron determines what?
Connection with other neurons and it contribution to the nervous system.
33
The function of a neurons is related to what?
Shape of the neuron
34
What type of cell helps synchronize the activity of the axon by wrapping around the presynaptic terminal and taking up chemicals that are released by the axon?
Astrocytes
35
Astrocytes are responsible for what?
Dilating blood vessels to bring more nutrients into brain areas with heightened activity
36
What type of cell removes waste material, viruses, and fungi from the brain?
Microglia
37
What else do microglia do?
Removes dead, dying or damaged neurons
38
Where are oligodendrocytes found?
Brain
| Spinal Cord
39
Where are schwann cells found?
Peripheral nervous system
40
What is the function of oligodendrocytes and schwann cells?
Build myelin sheath that surrounds and insulates certain vertebrae axons
41
What guides the migration of neurons and the growth of their axons and dendrites during embryonic development
Radial Glia
42
When embryonic development finishes, what do radial glia differentiate into?
Neurons and a smaller number differentiate into astrocytes and oligodendrocytes.
43
What is a mechanism that surrounds the brain and blocks most chemicals from entering?
Blood brain barrier
44
What destroys damaged or infected cells throughout the body?
Immune System
45
Because neurons in the brain generally don't regenerate, it's vitally important for the BBB to block what?
Incoming viruses, bacteria, or harmful material from entering the brain.
46
What is the protein mediated process that expends energt to pump chemicals from the blood into the brain?
Active transport
47
What are brought into the brain via active transport?
Glucose
Certain Hormones
Amino Acids
Few Vitamins
48
The BBB is essential to health but can pose difficulty in allowing what to pass the barrier?
Chemicals like chemotherapy for brain cancer
49
What type of neurons depends almost entirely on glucose?
Vertebrate Neurons
50
What is one of the few nutrients that can pass through the BBB?
Sugar
51
Neurons needs a steady supply of what?
Oxygen
52
20% of all oxygen consumed by the body is used by what?
Brain
53
What vitamin does the body need to use glucose?
Thiamine
54
Prolong thiamine deficiency leads to what?
Death of neuron-Korsakoff's Syndrome
55
Korsakoff's syndrome is a result of what?
Alcoholism
56
Korsakoff's syndrome is marked by what?
Severe memory impairment
57
What is the electrical message that is transmitted down the axon of a neuron?
Nerve Impulse
58
The nerve impulse doesn't travel directly down the axon but does what?
It's regenerated at points along the axon so it's not weakened.
59
What is the speed of a nerve impulse?
Less than 1 meter/second to 100 meters/second
60
A touch on the should reaches the brain more quickly that what?
Touch on foot
61
Messages in a neuron develp from disturbances of what?
Resting Potential
62
At rest, the membrane maintains an electrical gradient known as what?
Polarization
63
What is polarization?
Difference in electrical charge inside and outside of the cell
64
The inside of the membrane is what?
Slightly negative compared to the outside (-70mV)
65
The resting potential of a neuron refers to what?
State of neuron prior to sending nerve impulse.
66
The membrane is what, allowing some chemicals to pass more freely than others?
Selectively permeable
67
What passes through channels in the membrane?
Sodium (Na+)
Potassium (K+)
Chloride (Cl-)
68
When the membrane is resting what do the channels do?
Sodium channels closed (Na+ can't pass)
| Potassium channels partially closed (K+ passes)
69
What is a protein complex that continually pumps 3 sodium ions out of the cells while drawing 2 potassium ions into the cell?
Sodium-Potassium Pump
70
The sodium potassium pump helps to do what?
Maintain electrical gradient
71
Sodium potassium pump uses what?
Active transport (requiring ATP)
72
The electrical gradient and concentration gradient do what?
Work to pull sodium ions into the cell
73
The electrical gradient tends to pull what into cells
Potassium Ions
74
Potassium ions leak out of the electrical gradient carrying what?
Positive charge (K+)
75
The resting potential remains stable until what?
Neuron is stimulated
76
What increases the polarization or the difference between the electrical charge of two places
Hyperpolarization
77
What decreases the polarization toward zero?
Depolarization
78
What is a level above which any stimulation produces a massive depolarization?
Threshold of excitation
79
What is a rapid depolarization of the neuron?
Action Potential
80
The action potential threshold varies from what
One neuron to another but is consistent for each neuron.
81
Stimulation of the neuron past the threshold of excitation triggers what?
Nerve impulse or action potential
82
Action potentials back propagate into what?
Cell body and dendrites
83
Dendrites become more susceptible to structural changes that's responsible for what?
Learning
84
What is the law that states that the amplitude and velocity of an action potential are independent of the intensity of the stimulus that initiated it?
All or None Law
85
Action potentials are equal in what?
Intensity and speed within a given neuron
86
At the start of action potential, what are mostly outside the neuron?
Sodium Ions
87
At the start of an action potential what are mostly inside?
Potassium ions
88
When the membrane depolarizes, what open?
Sodium and potassium channels in the membrane
89
At the peak of the action potential what happens?
Sodium channels close
90
Membrane channels permeability depend upon what?
Voltage difference across membrane
91
When sodium channels are opened, what comes in?
Positively charged sodium ions and nerve impulse occurs.
92
After an action potential occurs, what happens?
Sodium channels are closed
93
The neuron is returned to it's resting state how?
Opening potassium channels
94
Potassium ions flow out due to what?
Concentration gradient and they take their positive charge with them.
95
The sodium potassium pump later restores what?
Original distribution of ions.
96
The process of restoring the sodium-potassium pump to its original distribution takes what?
Time
97
An unusally rapid series of action potentials can lead to what?
Buildup of sodium within the axon
98
The buildup of sodium in the axon can be what?
Toxic to a cell , but only in rare instances such as stroke and after use of certain drugs.
99
Local anestheic drigs block what?
Sodium channel and prevent action potentials from occuring (I.e. novacaine)
100
After an action potential, a neuron has what?
Refractory period
101
A refractory period occurs when?
When the neuron resists the production of another action potential.
102
What is the first part of the period in which the membrane cannot produce an action potential?
Absolute refratory period
103
What is the second part in which it takes a stronger than usual stimulus to trigger an action potential?
Relative refractory period
104
In a neuron, the action potenatial begins where?
Action Hilock (Swelling where axon exits soma)
105
What is the transmission of the action potential down the axon?
Propagation of the action potential
106
What is interrupted by short unmyelinated sections of nodes of Ranvier?
Myelin Sheath
107
What is an insulating material composed of fats and proteins?
Myelin
108
At each node of Ranvier, the action potential is regenerated by what?
Chain of positively charged ions pushed along by the previous segment.
109
The jumping of the action potential from node to node does what?
Provides rapid conduction of impulses
| Conserves energy for the cell
110
What is the disease in which myelin sheath is destroyed and is associated with poor muscle coordination and visual impairments
Multiple Sclerosis
111
What has short axons that exchange information with only close neighbors and don't produce action potentials?
Local Neurons
112
When local neurons are stimulated, they produce graded potentials that vary in what?
Magnitude and don't follow the all or none law.
113
Local neurons do what in proportion to the stimulation?
Depolarize or hyperpolarize
114
Why are local neurons difficult to study?
They are really small.
