Brainscape's Knowledge GenomeTM

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


See full index

Biology > The Nervous System > Flashcards

The Nervous System Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What are the two systems that make up the nervous system?

What do each consist of?

A

Central nervous system:

  • Brain
  • Spinal cord

Peripheral nervous system

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

What systems make up the peripheral nervous system?

A

Autonomic nervous system

  • Involuntary
  • Stimulates smooth muscle, cardiac muscle and glands

Somatic nervous system

  • Voluntary
  • Stimulates skeletal muscle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What two systems can the autonomic nervous system be divided into?

A

Sympathetic nervous system
-‘fight or flight’ responses

Parasympathetic nervous system
-‘rest and digest’ responses

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

When would a gland be stimulated?

A
  • When there is a change in the concentration of a specific substance
  • If they receive an electrical impulse
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What do hormones bind to?

A

Target cells

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

What is a nervous system receptor like in the resting state?

A
  • Difference in charge between the inside and outside of the cell
  • This means there is a voltage across the membrane
  • The membrane is said to be polarised
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is potential difference?

A

The voltage across the membrane

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

What happens in a receptor when a stimulus is detected?

A
  • Permeability of the cell membrane to ions changes
  • This stops the movement of ions in or out of the cell
  • This causes a change in the potential difference, which, if large enough, will trigger an action potential
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is an action potential?

A

An electrical impulse along a neurone

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

What pigment do rod cells contain?

A

Rhodopsin

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

What is rhodopsin made from?

A

Retinal and opsin

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

What happens when rod cells are stimulated?

A
  • Light energy causes rhodopsin to break down into retinal and opsin in a process called bleaching
  • The bleaching of rhodopsin causes the sodium ion channels to close
  • Sodium ions are moved out of the cell via active transport but can’t diffuse back in
  • Na+ ions build up outside the cell making the inside of the membrane more negative than the outside
  • The cell membrane is hyperpolarised
  • This stops the cell releasing neurotransmitters which means there is no inhibition of the bipolar molecule
  • The bipolar molecule depolarises which causes a change in potential difference
  • If the change in potential difference is large enough, an action potential is transmitted to the brain via the optic nerve
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What do dendrites do?

A

Carry nerve impulses towards the cell body of a neuron

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

What do axons do?

A

Carry nerve impulses away from the cell body of a neuron

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

Describe the structure of a motor neuron

A
  • Many short dendrites

- One long axon

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

Describe the structure of a sensory neuron

A
  • One long dendrite

- One short axon

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

Describe the structure of a relay neuron

A
  • Many short dendrites

- Many short axons

18
Q

What is the voltage across the membrane when it’s at rest?

A

-70 mV

19
Q

How is the resting potential created and maintained?

A
  • Sodium-potassium pumps move Na+ ions out of the neuron and K+ ions into the neuron
  • This creates a sodium ion electrochemical gradient as the sodium ions can’t re-enter the neuron
  • Membrane is permeable to K+ ions so they diffuse back out of the neuron through potassium ion channels
20
Q

Describe the sequence of events that make up an action potential

A

Stimulus

  • Neuron cell membrane becomes excited causing sodium ion channels to open
  • The membrane becomes more permeable to sodium, so Na+ ions diffuse into the neuron down the sodium ion electrochemical gradient
  • This makes the inside of the neuron less negative

Depolarisation

  • If the potential difference reaches the threshold, around -55 mV, more sodium ion channels open
  • This causes more Na+ ions to diffuse into the neuron

Repolarisation

  • When the potential difference is around +30 mV, the sodium ion channels close and the potassium ion channels open
  • K+ ions diffuse out of the neuron down the potassium ion concentration gradient
  • Membrane starts to return to its resting potential

Hyperpolarisation

  • Potassium ion channels are slow to close so too much K+ ions diffuse out of the neuron
  • The potential difference becomes more negative than the resting potential (less than -70 mV)

Resting potential

  • The ion channels are reset
  • The sodium-potassium pump returns the membrane to its resting state
21
Q

What happens in the refractory period?

A
  • The sodium and potassium ion channels are recovering and can’t open again for a while
  • Therefore the neuron cell membrane can’t become excited again straight away
22
Q

How does the action potential move along a neuron?

A

In a wave of depolarisation

23
Q

Compare nerve impulses and hormones

A

Nervous communication:

  • Uses electrical impulses
  • Fast response
  • Localised response
  • Short acting

Hormonal communication:

  • Uses chemical messengers in the blood
  • Slower response
  • Widespread response
  • Longer acting
24
Q

Describe the sequence of events​ from the action potential arrival at the presynaptic membrane of a synapse to the generation of a new action potential at the postsynaptic membrane (6)

A
  • Action potential arriving at the presynaptic membrane stimulates voltage gated Ca2+ ion channels to open
  • Ca2+ ions diffuse into the neuron
  • This causes synaptic vesicles, containing neurotransmitter, to move the to the presynaptic membrane
  • The vesicles fuse with the membrane and release the neurotransmitter into the synaptic cleft via exocytosis
  • The neurotransmitter diffuses across the synaptic cleft and binds to specific receptors on the postsynaptic membrane
  • This causes Ca2+ ion channels to open in the postsynaptic membrane
  • There is an influx of Ca2+ ions which causes depolarisation
  • This triggers a new action potential to be generated at the postsynaptic membrane
25
Q

What is a reflex?

A

A rapid, involuntary response to a stimulus

26
Q

Describe the reflex arc

A
  • Receptors detect a stimuli and generate an impulse
  • Sensory neurons conduct the impulse to the centre nervous system (CNS) by entering the spine through the dorsal route
  • Sensory neurone forms a synapse with a relay neurone
  • Relay neurone forms a synapse with a motor neurone
  • Motor neurone carries the impulse out of the spinal cord through the ventral route to effectors
  • Effectors produce a response
27
Q

What is the advantage of the reflex pathways?

A
  • They produce rapid responses

- Important for survival

28
Q

Describe the nervous pathways involved in the increase of heart rate when starting to exercise

A
  • Cardiovascular control centre in brain detects increase in CO2 and lactate in the blood
  • Sensory receptors in muscles send impulses to cardiovascular control centre along sensory neurons
  • Impulses sent from cardiovascular control centre to SAN via sympathetic nerve
  • Impulses from SAN to heart muscles increases in frequency, causing heart rate to rise
29
Q

Where are dendrons found?

A

Before the cell body in a sensory neuron

30
Q

Where are axons found in neurons?

A
  • After the cell body

- Carrying the impulse away

31
Q

Where are the cell bodies of sensory neurons found?

A

-In the Ganglia

32
Q

What is the Ganglia? Where is it?

A
  • The place where cell bodies of sensory neurons are found

- Near the spinal cord

33
Q

What are on the ends of sensory neurons?

A

Dendrites

34
Q

Compare and contrast the structure of motor and sensory neurones

A
  • Both have a long nerve fibre
  • In a motor neurone this nerve fibre is an axon
  • In a sensory neurone it is a dendron
  • Sensory neurones have their cell body in the middle of neurone while motor neurones have the cell body at the start of the neurone
35
Q

Explain how the parasympathetic and sympathetic branches of the autonomic nervous system work antagonistically

A
  • Antagonistic means working in opposition to each other
  • Changes made by the sympathetic system can be reversed by the parasympathetic system
  • They allow changes to be made, for example when regulating heart beat
36
Q

What is the motor-end plate?

A

Where a neurone and muscle meet

37
Q

What are Schwann cells? What do they do?

A

-Forms a myelin sheath around an axon

38
Q

Where are nodes of Ranvier found?

A

In between Schwann cells on the myelin sheath

39
Q

How does a myelin sheath increase the speed of impulses?

A
  • Acts as an electrical insulator
  • Ensures depolarisation only happens at the nodes of Ranvier
  • Impulse travels from node to node, decreasing the points at which depolarisation can take place along an axon
40
Q

What is it called when an impulse is insulated by a myelin sheath?

A

Saltatory conduction

41
Q

Why is an impulse along a non-myelinated neurone slower than an impulse along a myelinated one?

A
  • In a non-myelinated neurone the impulse travels as a wave along the whole length of the axon membrane
  • In a myelinated neurone, the impulse can only travel from node to node, reducing the amount of axon membrane that the impulse travels along
42
Q

Why is the refractory period important?

A
  • In the refractory period, an impulse cannot travel along a neuron until the resting potential has been reached
  • This keeps the wave of depolarisation moving forward as the membranes behind the impulse cannot carry the impulse as they have not reached the resting potential yet

Biology (20 decks)

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