Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Behavioural Neuroscience > Neurons and Communication in the Brain > Flashcards

Neurons and Communication in the Brain Flashcards

(88 cards)

Start Studying
1
Q

how many neurons does the human brain contain?

A

100 billion or more

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

up to how many neurons can one neuron be connected to?

A

10,000 other ones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

where does neurogenesis occur?

A

not born with full set of neurons
neurogenesis occurs in some parts of the brain: olfactory bulb, hippocampus and amygdala

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

how many cortical neurons do we lose each second?

A

1 each second
neurons have a high metabolic rate and require a continuous source of fuel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the nervous system?

A

one of the body’s major command and control systems
complex system with 100 billion cells in the brain which is interconnected and interacting in complex ways

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

how is the nervous system divided?

A

into the central and peripheral nervous system
CNS: brain and spinal cord
PNS: everyone outside the brain and spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

how is the peripheral nervous system divided?

A

into the somatic and autonomic nervous system
somatic: controls movement and muscles and registers touch
autonomic: controls automatic processes like heart rate, organs, stress

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

how is the autonomic nervous system divided?

A

into sympathetic and parasympathetic nervous system
sympathetic: gets body ready for fight or flight
parasympathetic: calms body for rest and digest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what does the volume of the CNS consist of?

A

neurones consist of half the volume of the CNS
supporting cells consist of the other half

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are supporting cells?

A

supporting cells provide neurons with nutrients from the capillaries and keep neurons from getting damaged

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

why are the supporting cells important?

A

neurons have a very high metabolic rate but have no means of storing nutrients so they must constantly be supplied with nutrients and oxygen or they will quickly die

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

types of supporting cells (glia cells)

A

astrocytes
oligodendrocytes
schwann cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

function of astrocytes

A

serve as the matrix that holds neurons in place to insulate them
delivers nutrients from blood supply to neurons
surrounds and isolates synapses to limit the dispersion of neurotransmitters that are released by the terminal buttons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

structure of astrocytes

A

located in the centre and connect to many neurons
many thin tendrils go out and attach to the soma of neurons and capillaries
these thin tendrils have U-shaped buttons that attach

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

function of oligodendrocytes

A

provide support for neurons in the CNS by wrapping around axons to form the myelin sheath which speeds up the communication in the brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

structure of oligodendrocytes

A

has a soma similar to the structure of a neuron
many tendrils go out of it which merge with the myelin sheaths of the surrounding axons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

function of schwann cells

A

provide support for sensory and motor neurons in the PNS by wrapping around axons to form the myelin sheath which speeds up communication between neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

structure of schwann cells

A

large circular structure that engulfs axon by wrapping itself round in many layers that form the myelin sheath

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is the blood brain barrier?

A

a semipermeable barrier between the blood and the brain produced by the cells in the walls of the brain’s capillaries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

properties of the blood brain barrier

A

selectively permeable so some substances e.g. water molecules can pass through the cells of the capillaries passively whereas other molecules enter via active transport which requires ATP to move between the tightly packed cells of the capillaries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what are sensory neurons?

A

a neuron that detects changes in the external or internal environment from receptors in skin, tongue etc and sends information about these changes to the CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what are motor neurons?

A

a neuron that controls the contraction of a muscle or the secretion of a gland, cell body located in the CNS but axons go to PNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what are interneurons?

A

a neuron that connects sensory and motor neurons; located entirely within the CNS
doesn’t have a long axon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

which processes to do with neurons require the brain and which do not?

A

reflex arcs do not require the brain
inhibition requires the brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
how does a reflex arc work?
The axon of the sensory neuron carries the pain signal from the hand holding the hot object to the interneuron in the spinal cord The interneuron in the spinal cord excites the motor neuron, causing a withdrawal reflex of the hand
26
how does inhibition of a reflex arc work?
The axon of the sensory neuron carries the pain signal from the hand holding the hot object to the interneuron in the spinal cord The interneuron has inhibitory signals from the brain which inhibits the motor neuron from withdrawing, ergo preventing the hand from dropping the object
27
what are synapses?
where two neurones join together without touching
28
what are dendrites?
similar structure to trees carry signals from a receptor/synapse to the cell body
29
what are axons?
has myelin sheath wrapped around carry signals away from the cell body to the terminal buttons
30
what are terminal buttons?
where synapses occur found at the end of an axon
31
what is the soma?
cell body contains the cytoplasm and nuclei with DNA
32
what is the function of the neuron?
to transmit signals from one part of the body to another
33
what are multipolar neurones?
most common type of neuron consist of a single axon and multiple dendrites with the cell body near the dendrites
34
what are bipolar neurons?
consist of one dendrite and one axon with cell body in the middle often sensory neurons
35
what are unipolar neurons?
single axon with the cell body located on one side
36
what structures can be found into the soma?
membrane cytoplasm mitochondria nucleus chromosome microtubule ribosomes
37
define membrane
a structure consisting principally of lipid molecules that defines the outer boundaries of a cell and also constitutes many of the cell organelles
38
define cytoplasm
the viscous, semiliquid substance contained in the interior of a cell
39
define mitochondria
an organelle that is responsible for extracting energy from nutrients
40
define ribosome
protein synthesis site
41
define nucleus
a structure in the central region of a cell, containing the chromosomes
42
define chromosome
a strand of DNA, with associated proteins, found in the nucleus; carries genetic information
43
define microtubule
part of the cytoskeleton; transports substances like neurotransmitters and proteins
44
how does the microtubules transport material?
anterograde axoplasmic transport: transports large neurotransmitters and proteins from cell body to terminal buttons retrograde transport: transports material like recycled neurotransmitters from the terminal buttons to the soma
45
how are large neurotransmitters made and transported?
made in the soma transported via anterograde axoplasmic transport from cell body to terminal buttons
46
how are small neurotransmitters made and transported?
made in the terminal buttons and do not need to be transported
47
what is an electrode?
a conductive medium that can be used to apply electrical stimulation or to record electrical potentials
48
what is a microelectrode?
a very fine electrode, generally used to record activity of individual neurons
49
what is membrane potential?
the electrical change across a cell membrane; the difference in electrical potential inside and outside of the cell
50
how was neuron activity initially measured?
measured charge of axon using giant squid as their axons are much thicker than humans did this by putting axon in saltwater and measuring the charge of the saltwater and the charge inside the squid axon
51
how does communication along axon occur?
occurs due to changes in charge within the axon compared to outside the axon
52
what makes up the charge outside the axon at resting potential?
lots of sodium ions outside (Na+) inside is relatively negative compared to outside
53
what makes up the charge inside the axon at resting potential?
lots of potassium ions inside (K+) lots of anions inside (-) makes overall charge inside relatively negative compared to outside
54
why is there are build up of anions inside?
anions cannot leave due to the impermeability of the cell membrane
55
what is resting potential?
-70mv
56
what are the 3 pressures that act on the ions to maintain resting potential?
diffusion electrostatic forces sodium-potassium pump
57
how does diffusion maintain resting potential?
movement of substances from an area of high concentration to an area of low concentration along concentration gradient pressure for sodium ions to move into the axon as there is less inside than outside and pressure for potassium ions to move out of the axon as there is less outside than inside
58
how do electrostatic forces maintain resting potential?
negative and positive charges attract positive sodium and potassium ions move into the axon as it is negative
59
how does the sodium-potassium pump maintain resting potential?
active transport pumps 3 sodium ions out for every 2 potassium ions in which maintains the resting potential
60
what happens to chloride ions?
negatively charged remain at equilibrium
61
how was the first action potential found?
by Darwin in a venus fly trap
62
what is an action potential?
the brief electrical impulse that provides the basis for conduction of information along an axon
63
what is threshold of excitation?
the value of the membrane potential that must be reached to produce an action
64
how does an action potential work?
1. stimulus triggers a change in charge called the action potential which travels along the axon 2. this stimulus must reach a certain threshold of -60mv for an action potential to be fired 3. once this threshold is reached, sodium ion channels open and sodium ions flood in which increases the membrane potential to +40mv inside the axon 4. at the same time potassium ion channels open and potassium ions leave 5. due to the influx of ions in and out of the axon, once the membrane potential reaches +40mv, the sodium ion channels become refractory so diffusion no longer occurs and less sodium ions enter 6. this causes the membrane potential to decrease as potassium ions continue to leave 7. membrane potential returns to resting potential as potassium ion channels close 8. too many potassium ions leave so hyperpolarisation occurs which requires the sodium-potassium pump to bring the membrane potential back to resting potential
65
how is an action potential triggered?
Activation by a previous neuron after a synapse or activation by previous action potential
66
explain the process of depolarisaiton
1. at the start of an action potential, sodium ions enter the axon and diffuse along the axon via diffusion as it is negative - this increases the membrane potential 2. depolarisation decreases as the action potential spreads down the axon but it is still enough to trigger a new action potential at the next node of Ranvier as the myelin sheath prevents an action potential from firing 3. this process repeats at each node of Ranvier
67
what is saltatory conduction?
Saltatory conduction is when the action potential jumps from node to node which speeds up the velocity at which an axon can conduct an action potential as it does not have to depolarise every bit of the axon
68
if decremental conduction of message is faster than action potentials, why are action potential important?
Depolarisation decreases as it spreads down the axon but it is still enough to trigger a new action potential at the next node but would peter out before getting to the end of the axon
69
what is the all or none law?
the principle that once an action potential is triggered in an axon, it is propagated, without decrement, to the end of the fiber action potentials are always the same size
70
what is the rate law?
the principle that variations in the intensity of a stimulus or other information being transmitted in an axon are represented by variations in the rate at which that axon fires. intensity of the action potential is detected by the rate of action potential
71
when are myelin sheaths required and not required?
Myelin sheaths are not required when travelling short distances e.g. interneurons and some brain neurons travel small distances so do not require a myelin sheath Myelin sheaths are required for travelling long distances e.g. along the spinal cord and in the peripheral NS
72
what is the presynaptic membrane?
the membrane of a terminal button that lies adjacent to the postsynaptic membrane and through which the neurotransmitter is released
73
what is the postsynaptic membrane?
the cell membrane opposite the terminal button in a synapse; the membrane of the cell that receives the message
74
what is the synaptic cleft?
the space between the presynaptic membrane and the postsynaptic membrane
75
common neurotransmitters
Acetylcholine Dopamine Noradrenaline (norepinephrine) Serotonin (5-HT) Glutamate GABA
76
what are the 4 stages of the lifecycle of neurotransmitters?
synthesis release binding inactivation
77
explain how neurotransmitters are synthesised
- Small neurotransmitter molecules are synthesised in the terminal buttons and packaged into synaptic vesicles - Large neurotransmitter molecules are assembled in the cell body, packaged in vesicles and then transported to the axon terminal via microtubules
78
explain how neurotransmitters are released
When an action potential arrives, the synaptic vesicles fuse with the presynaptic membrane and neurotransmitters are released into synaptic cleft.
79
explain how neurotransmitters are binded
The neurotransmitters move across and bind to receptors on the postsynaptic neuron
80
what are the two different types of receptors on the postsynaptic membrane?
ionotropic receptors and metabotropic receptors
81
what are ionotropic receptors and how do they work?
Receptors that control ion channels Ligand gated ion channels respond to the presence of neurotransmitters and cause postsynaptic potentials which can be inhibitory or excitatory depending on the ion
82
what happens to an excitatory potential at the postsynaptic membrane?
Excitatory potential means Na+ channels are opened which leads to an action potential firing again as the inside of the axon becomes positive due to sodium ions flowing in and the process of depolarisation repeats
83
what happens to an inhibitory potential at the postsynaptic membrane?
Inhibitory potential means K+ channels are opened which leads to an action potential not firing as the inside of the axon is too negative due to potassium ions flowing out
84
what are metabotropic receptors and how do they work?
Slower and less direct mode of action An autoreceptor is a type of metabotropic receptor located on the presynaptic membrane and is sensitive to the neurotransmitter released. The neurotransmitter and the metabotropic receptor travels through a channel and has an effect on the G-protein which changes the shape of a protein which effects the second messenger which affects the ion channel
85
explain how neurotransmitters are inactivated
The two mechanisms for terminating neurotransmitter action in the synapse: reuptake and enzymatic degradation reuptake: e.g. dopamine is recycled to be used again enzymatic degradation: e.g. Acetylcholine is broken down by AcHE, the products are recycled by astrocytes and go back to the soma
86
what effect does drugs have on inactivation of neurotransmitters?
Some drugs e.g. opiates may block the autoreceptors so dopamine cannot be recycled by reuptake and stays in the synapse - this creates a high-like effect due to the build up of dopamine in the synapse
87
how can you inhibit excitatory reflexes?
88
neural integration
1. If several excitatory synapses are active at the same time, the EPSPs they produce summate as they travel toward the axon and the axon fires 2. If several inhibitory synapses are active at the same time, the IPSPs they produce diminish the size of the EPSPs and prevent the axon from firing

Behavioural Neuroscience (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions