Brainscape's Knowledge GenomeTM

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


See full index

Biology Unit 3 > Nervous System (DONE) > Flashcards

Nervous System (DONE) Flashcards

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

What does the (peripheral) nervous system enable?

A

Enables animals to respond to changes in the external or internal environment known as stimuli

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

Label the anatomy of a spinal cord. Use the image below to label.
https://images.app.goo.gl/B5eSLQsn5nybDFhFA
(8 labels)

A

Should include
- Central canal
- Grey matter
- Whiter matter
- Dorsal root ganglion
- Sensory neurone
- Relay neurone
- Motor neurone
- Dorsal/ventral root

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

Describe the following briefly:
- Grey matter
- White matter
- Central canal
- Meninges

A
  1. Grey as it contains cell bodies and nuclei
  2. White as many axons wrapped in the lipid myelin, pass through this region
  3. Contains cerebrospinal fluid
  4. Surrounded the spinal cord
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the reflex arc briefly (what does it provide)?

A

A fast, automatic (involuntary) response to a stimulus that has a protective function

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

Write out the nervous response pathway
(7 parts)

A
  1. Stimulus
  2. Receptor
  3. Sensory neurone
  4. Relay neurone in CNS
  5. Motor neurone
  6. Effector
  7. Response
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are effectors?

A

A muscle or gland

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

Describe the structure and functioning of nerve nets in simple organisms such as hydra (use image for reference if required)
(3 marks)

A
  • Receptors respond to a limited number of stimuli therefore the number of effectors in small.
  • They have nerve nets of identical branching neurones that are interconnected
  • The neurones are unmyelinated and send impulses in all directions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Label a diagram of the motor neurone https://images.app.goo.gl/QrghV33cCTrsPEMNA
(6 labels)

A

Should include
- Dendrites
- Cell body
- Schwann cells which form the myelin sheath
- Nodes of Ranvier
- Axon
- Axon Endings

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

What are the functions of the following:
- Dendrites
- Schwann cells
- Nodes of Ranvier
- Axon
- Axon endings

A

Dendrites transmit impulses into the cell body
Schwann cells wrap around the axon and form the myelin sheath, an electrical insulator
Nodes of Ranvier are gaps in the myelin sheath, that form long local circuits with the next node, speeding up transmission
Axon transmits the impulse to the axon endings
Axon endings innervate effectors

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

How is a nerve impulse caused (briefly)
(2 marks)

A

Na and K ions moving across the neurone membrane. This causes a potential difference in electrical charge between the inside and outside of the membrane (membrane potential)

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

Describe what occurs at resting potential/how is resting potential achieved
(4 marks)

A
  • The neurone is not transmitting an impulse
  • The membrane is polarised at -70mV
  • Na/K pump uses ATP to move 3Na out of the axon and 2K ions in the axon
  • The K ions diffuse out of the axon, but Na ions cannot diffuse in, causing a charge difference.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe what happens to achieve action potential/depolarisation
(4 marks)

A
  1. A stimulus is received causing Na ion channels to open
  2. Na ions diffuse into the axon, making the inside of the cell less negative compared to the outside of the cell
  3. When the threshold potential is reached, all the Na ion channels open so that Na ion rapidly diffuse into the axon.
  4. The membrane depolarises to +40mV.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the threshold of excitation/all-or-nothing principle?

A

The level of depolarisation needed to generate the action potential

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

How is repolarisation/hyperpolarisation achieved?

A
  1. Na channels close and K channels open
  2. Potassium ions diffuse out rapidly
  3. Overshoot causes hyperpolarization
  4. Resting potential is restored by the sodium/potassium pump
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the refractory period?
(2 marks)

A
  • The period of hyperpolarization in an action period
  • Action potential cannot be stimulated again instantly to ensure that wave of depolarisation travels in one direction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How is action potential measured?

A

Cathode Ray Oscilloscope (CRO)

17
Q

What is passive conduction and what will it ensure? Why is it better than continuous action?
(3 marks)

A
  • It is the diffusion of ions along the axon
  • Ensures that adjacent membrane depolarises so that action potential travels
    down the axon.
  • Transmission by continuous action is slow and energy consuming from the Na/K pumps
18
Q

What are the factors affecting transmission speed and briefly explain how.
(3 marks)

A
  • Larger axon diameter provides less resistance
  • Higher temperature increases the rate of diffusion
  • Myelin sheath means depolarisations occurs only at Nodes of Ranvier. Saltatory conduction
19
Q

What is saltatory conduction?
(2 marks)

A

The action potential only occurs at the unmyelinated regions (Nodes of Ranvier)
- A faster mechanism evolved being saltatory conduction, which is provided by myelination as action potential ‘jump’ from one node to the next

20
Q

Label the structure of the synapse
(6 marks)

A

Include:
- Synaptic cleft
- Presynaptic membrane
- Postsynaptic membrane
- Receptors
- Vesicles containing neurotransmitter
- Calcium ion channels

21
Q

What is the main neurotransmitter?

A

Acetylcholine / (noradrenaline)

22
Q

Describe the sequence of events for synaptic transmission
(7 marks)

A
  1. Depolarisation/action potential of the axon membrane causes Calcium ion channels to open
  2. Calcium ions diffuse into the synaptic knob
  3. Calcium causes vesicles containing neurotransmitter to fuse with presynaptic membrane
  4. Neurotransmitter released by exocytosis into synaptic cleft
  5. Neurotransmitter diffuses across cleft and bins to receptors on postsynaptic membrane
  6. Binding causes Sodium ion channels on post/membrane to open. Sodium ions diffuse into postsynaptic membrane causing depolarisation
  7. Enzyme breaks down neurotransmitter. Products taken into synaptic knob by endocytosis, where they are resynthesized into more neurotransmitter
23
Q

How is the single direction of an impulse maintained?
(3 marks)

A
  • Acetylcholine/neurotransmitter is only made in presynaptic membrane
  • Receptors are only on postsynaptic membrane
  • Refractory period prevents action potential
24
Q

Describe the effect of antagonists and agonists on the synapse

A

Antagonists
- Affects synapse by preventing postsynaptic depolarisation (sedative)
Agonists
- Cause more postsynaptic depolarisation (stimulant)

Biology Unit 3 (7 decks)

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