Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physiology 208 > 4. Chapter 8- Neurons > Flashcards

4. Chapter 8- Neurons Flashcards

1
Q

How is the nervous system broken down?

Slide 7 on sept 19

A

Nervous system- peripheral nervous system (PNS) and central nervous system (CNS)
PNS- sensory division of PNS and efferent division of the PNS
Efferent PNS- autonomic neurons and somatic motor neurons
Autonomic neurons- sympathetic and parasympathetic

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

What are afferent, efferent, and interneurons?

A

Afferent- carry information towards CNS, sensory carry info about temperature, pressure, light and stimuli to CNS
Efferent- carry information away from CNS, motor and autonomic, motor controls skeletal muscles and autonomic influences many internal organs
Interneurons- complex branching neurons that facilitate communication between neurons

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

What’s is the central nervous system and and the peripheral nervous system?

A

CNS- brain and spinal cord
PNS- nerve tissue outside the CNS: cranial nerves and branches, spinal nerves and branches, ganglia, plexuses and sensory receptors

CNS has an efferent division leaving it
And an afferent division coming into it (slide 9 sept 19)

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

What are neurons and glia?

What are satellite glial cells?

A

Neurons- basic signalling units it the nervous system
Glia- (glue) support cells (more glial cells than Neurons by 1-4 to 1) communicate with neurons and provide biochemical support

Satellite glial cells exist within the ganglia (bundles of cell bodies) within the PNS
They form a supportive capsule around the cells bodies of neurons and supply nutrients
Slide 12 sept 21 neuro 3

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

What are the parts of a neuron?

Slide 11 on sept 19

A

Cell body (soma)- control centre with processes that extend outward, contains Nucleus
Dendrites- review incoming signals from neighboring cells
Axons- carry outgoing signals from the integrating centre to target cells
Presynaptic terminals- contain transmitting elements

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

How do the Neurons compare for somatic senses and neurons for smell and vision?

A

Somatic senses have Schwann cells covering the long lines axon
Schwann cells are myelin sheaths

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

What are the structural categories of neurons?

A

Pseudounipolar- single process called the axon, dendrite fused with axon during development
Bipolar- two equal fibres extending off the central body
Anaxonic- interneurons that have no apparent axon
Multipolar- interneurons that are highly branched but lack long extensions, 5-7 dendrites
Slide 12 on sept 19

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

Study the breakdown of a peripheral nerve on slide 14 on sept 19

A

Okay

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

How are proteins made in neurons?

A

Made in cell body then transported down the axon

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

What is fast axonal transport vs slow axonal transport?

A

Fast- membrane bound organelles (vesicles or mitochondria)
- anterograde: cell body to axon terminal 400mm/day
- retrograde: axon terminal to cell body 200mm/day
Slow- cytoplasmic proteins (enzymes) and cytoskeleton proteins
- anterograde, 8mm/day
- not well characterized, may be slower due to frequent periods of lashing movements

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

What are kinesins and dyeins?

A 
Motor proteins
Kinesins- anterograde transport (cell body to axon terminal)
Move towards positive end 
Dyeins- retrograde transport
(Axon terminal to cell body)

ATP hydrolysis droves movement of proteins to walk along filaments

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

What are synapses?

What are the two types?

A

Region of communication between two neurons or a neuron and another cell
Space contain extracellular matrix that hold the pre and post synaptic cells close
Post synaptic cells receives dendrite

Chemical synapse uses chemicals
Electrical synapse use gap junctions that connects intracellular fluid of one neuron to the ICF of another
Much faster than chemical

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

How are synapses formed? What

A

Axons of embryonic neurons contain growth comes that sense and move towards particular chemical signals
Once reaching a target cell a synapse forms

We are born with the amount of neurons we will use for life only thing is over time they make more connections

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

What is myelin?

A

A substance composed of multiple concentric layers of phospholipid membrane wrapped around an axon
More thick the myelin, more insulation, faster the signal moves
Look at pictures of myelin on slide 10 on sept 21 (neuron3)

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

What is demyelination and the disease with it?

A

Multiple sclerosis is a disorder resulting from demyelination in brain and spinal cord
Immune cells attack myelin (autoimmune)
Reduced ability of myelin producing cells

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

What are astrocytes?

A

Highly branched glial cells in CNS that make up half of all cells in brain
They take up and release chemicals at synapses
Provide Neurons with substrates for atp production
He’ll maintain homeostasis

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

What are microglia?

A

Specialized immune cells that reside in the CNS
Protect and preserve neuronal cells from pathogens and facilitate recovery from metabolic insults
ALS and Alzheimer’s is causes when the signal that activate microglia pass a threshold or microglia remain activated too long and these cells start to display detrimental properties

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

What are ependymal cells?

A

Like fluid filled cavities in the brain and spinal cord
Help circulate cerebrospinal fluid that fills these cavities and surrounds the brain and spinal cord
Picture on slide 15 and 16 on sept 21

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

What is peripheral neuron injury?

A

When an axon is cut, the section attached to the cell body still lives and the other section begins to disintegrate
It can reform the synapse by regrowing through the existing sheath of Schwann cells
Slide 17 and 17 sept 21 neuro 3
In cns repair is less likely to occur so glial seal off and form scar tissue

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

What is the Goldman-Hodgkin-Katz equation used for?

A

Predicts membrane potential that results from the contribution of all ions that can cross the membrane
Add the combined contribution of each ion to the membrane potential
Close to Nernst equation but different cause it doesn’t count equilibrium potential

21
Q

What is the resting membrane potential in most neurons?

A

~-70mV
Mainly due to K+
Cell is already negative and K+ drops it down to -70

22
Q

How is ion permeability controlled in neurons?

A

Ion permeability is altered by opening or closing ion channels in the membrane
New open channels can be added or removed
Na+ channels
K+ channels
Ca2+ channels
Cl- channels
Channels conductance is how easy ions are allowed to move through that channel

23
Q

What are the three types of gated channels?

A
  1. Mechanically gated channels- open in response to physical forces (pressure or stretch)
  2. Chemically gated ion channels- Neurons respond to ligands including extracellular neurotransmitters and meuromodulators or intracellular signalling molecules
  3. Voltage-gated channels- respond to changes in the cells membrane potential
24
Q

What are channelopathies?

A

Can disrupt how ions normally flow through ion channel
Can alter channel activation and inactivation
Picture on slide 14 of sept 24

25
Q

What is Ohm’s law?

A 
Current flow (I) is directly proportional to the electrical potential difference (V) between two points and inversely proportional to the resistance (R) 
Two sources of resistance are membrane resistance and internal resistance of the cytoplasm
26
Q

What are the two types of electrical signals in Neurons?

A

Graded potentials- travel short distances and lose strength
Can be depolarizing or hyperpolarizing
Generated by chemically gated ion channels or closure of leak channels
Action potentials- brief large depolarizations travel for long distances without losing strength
Picture of both on slide 17 and 18

27
Q

Why do graded potential lose strength as they move throughout a cell?

A

Current leak- open channels allow ions to leak out

Cytoplasmic resistance

28
Q

What is the trigger zone?

A

An area where if graded potential reach it, it can fire an action potential
Picture on slide 21 on sept 24

29
Q

What is the action potential (AP) of a neuron?

What is conduction?

A

Electrical signals of uniform strength (all-or-none) that travel from the trigger zone to the axon terminals
Opening of voltage gated K+ and Na+ ion channels in axon membrane as electrical current moves down
Movement of AP along axon is known as conduction of AP

30
Q

What two ions move across the membrane doing action potentials?

A

Na+ and K+ move across
They are both activated by depolarization
K+ channels open more slowly

31
Q

What is the rising phase, falling phase, and after-hyperpolarization phase of action potential?

A 
Rising phase (depolarization)- open Na+ channels to move down electrochemical gradient
Falling phase (repolarization)- k+ channels also open but do more slowly causing delayed efflux
After-hyperpolarization phase (undershoot)- K+ gates do not immediately close when -70mV is reached which causes membrane potential to dip below resting membrane potential
32
Q

How do voltage gated Na+ channels suddenly close at the peak of an AP?

A

They contain two gates: an activation gate and an inactivation gate
Slide 16 on sept 26
Inactivation hates cause feedback loops
Slide 17 on sept 26

33
Q

What is an absolute refractory period and a relative refractory period?

A

Double gating of Na+ channels creates a refractory period
Absolute refractory period- a second AP cannot be initiated 1-2msec
Relative refractory period- a second AP can be initiated but requires a larger than normal stimulus (graded potential)
2-5msec

34
Q

Study the steps of action potentials as they are conducted on slide 20 of sept 26

A

Okay

35
Q

What are the two physical parameters that determine the velocity of action potentials?

A
  1. Diameter of the axon- larger diameter axon will offer less internal resistance to current flow
  2. The resistance of the axon membrane to ion leakage- current will spread to more adjacent sections more rapidly of it is not lost via leak channels (myelin)
36
Q

What is saltatory conduction?

A

Conduction that occurs from node to node

Action potentials appear to jump for one node of ranvier to next

37
Q

What is demyelination?

A

Diseases that reduce or block conduction when current leaks out of the previously insulated regions between the nodes
Slide 9 and 10 on sept 28

38
Q

How can chemical factors alter electrical activity?

A

Slide 12 sept 26

Hyperkalemia increases blood K+ concentration and depolarizes cell
Hypokalemia decreases blood K+ concentration and hyoerpolarizes cell

39
Q

What is electrical synapses and chemical synapses?

A

Electrical- some CNS neurons, cardiac muscle, smooth muscle
Ions flow from one cell directly to the next
Slide 13 sept 26
Chemical- majority of neurons in nervous system use chemical signals
Electrical signals from presynaptic cell is converted to neurocrine signal that crosses the synaptic cedar and binds to a receptor on the post synaptic cell
Slide 14 sept 26

40
Q

What is neurocrine and neurotransmitters, neuromodulators, and neurohormones?

A

Neurocrine- chem Jak substance released from neurons used for cell to cell communication (includes neurotransmitters, neuromodulators, and neurohormones)
Neurotransmitters- causes a rapid response in post synaptic cell
Neuromodulators- causes a slow response in post synaptic cell
Neurohormones- secreted into blood stream and act on targets throughout body

41
Q

What are the two categories of neurocrine receptors?

A

Ionotropic receptors- ligand gated ion channels can be specific for one ion
Mediate fast postsynaptic responses
Metabotropic receptors- G protein coupled receptors
Slower responses
Interacts directly with ion channels or activate membrane bound enzymes
Slide 17-18 on sept 26

42
Q

What are the two types of metabotropic receptor results of Logan binding to a metabotropic receptor?

A
  1. Interact directly with ion channels
    Leads to opening or closing of a channel depending on G protein
  2. Interaction with a membrane bound enzyme
    Has two main types Phospholipase C signal transduction pathway (increase in Ca2+ causes cellular response)
    and Adenylyl Cyclase signal transduction pathway (PKA phosphorylation proteins to cause cellular response)
    Slides 18-21 on sept 26
43
Q

How is a neurotransmitter released?

How is it terminated?

A

It occurs via Ca2+ mediated exocytosis
The pre synaptic terminal contains a high concentration of voltage gated Ca2+ channels
Slide 12 Oct 1
Rapid removal or inactivation of neurotransmitter in synaptic cleft
Neurotransmitter binding depends on the concentration in the cleft
Slide 13 oct 1

44
Q

How does the strength of a stimulus affect the amount of neurotransmitter released?

A

Weak stimulus releases little neurotransmitter
Strong stimulus releases more action potentials and more neurotransmitter
Slide 14 Oct 1

45
Q

What is convergence and divergence in synaptic integration?

A

Convergence is many presynaptic Neurons May converge on one or a small number of postsynaptic Neurons
Divergence is where Neurons can have branching axons that contact many different postsynaptic Neurons
Pictures on slide 15 oct 1

46
Q

What is spatial summation?

A

Occurs when the currents from multiple nearly simultaneous graded potentials combine
Can also be inhibitory (postsynaptic inhibition)

Picture on slide 16 and 17 oct 1

47
Q

What is temporal summation?

A

Graded potentials from the same presynaptic neuron arriving at the trigger zone near simultaneously to be summated
Slide 18 oct 1

48
Q

What is presynaptic inhibition and presynaptic facilitation?

A

Inhibition- inhibits neurotransmitter release
Facilitation- increases neurotransmitter release
Pictures on slide 20 oct 1

49
Q

What is post synaptic modulation?

A

Synaptic activity can be altered by changing the target (post synaptic) cells responsiveness to neurotransmitter
By changing structure, affinity or number of neurotransmitter receptors

Physiology 208 (22 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions