Neurones Flashcards

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1
Q

Why can receptors be considered transducers?

A

They convert one type of energy into an electrical impulse

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2
Q

What is the charge of the inside and outside of a neurone?

A

Inside negative

Outside positive

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3
Q

What is the resting potential of a neurone?

A

-70mV

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4
Q

Draw a Pancinian Corpuscle

A

Sensory neurone with connecting tissue (lamellae)

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5
Q

Explain how pressure on a Pancian C, causes an action potential

A
  1. The shape of the corpuscle is changed
  2. Causing Stretch mediated sodium channels in the neurone membrane to open
  3. Sodium ions diffuse into the concentration gradient
  4. Depolarising the membrane
  5. Called a generator potential
  6. The greater the pressure the more stretch mediated channels open causing a bigger generator potential
  7. If threshold is reached an action potential develops and is transmitted along the neurone
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6
Q

When is a action potential triggered?

A

When the generator potential reaches the threshold

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7
Q

Explain adaptation in neurones?

A

When pressure is first applied impulses are transmitted along the neurone
With continuous pressure the frequency of the action potentials decreases, and then after a while may stop altogether
It prevents the nervous system from being overloaded with insignificant information

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8
Q

What piece of equipment could be used to measure potential difference

A

Voltmeter

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9
Q

Explain how testing potential is established and maintained

A
  1. There is a higher concentration of sodium ions on the outside than on the inside and a higher concentration of potassium ions on the inside than the outside of the axon
  2. The membrane is relatively impermeable to both K and Na but is less permeable to NA so more K diffuse out than Na in
  3. This means there are more positive ions outside the membrane and the membrane is said to be “polarised”
  4. The resting potential is maintained by the SODIUM POTASSIUM PUMP which pumps 3 Na out and pumps 2 K ions in
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10
Q

What happens when a neurone is stimulated? (Simple)

A

A nerve impulse starts when the resting potential across the neurone membrane is converted into an action potential

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11
Q

Draw a graph to correctly demonstrate how a membrane is stimulated

A

Include generater potential and restin and action, label with depolarisation and depolarisation and hyperpolarisation

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12
Q

Explain how a neurone is depolarised

A
  1. During an action potential, one section is depolarised
  2. This depolarisation of one section of membrane causes local currents
  3. These currents cause the voltage sensitive sodium ion channels to open, increasing the permeability if the membrane to sodium ions so causing depolarisation leading to the development of an action potential
  4. The nerve impulse can only travel in one direction due to the hyperpolarisaton of the membrane
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13
Q

Explain Saltatory conduction

A

In a myelinated nerve the depolarisation/ action potential jumps from node to node
The effect of the myelin sheath is to speed up conduction
Typical speed of conduction is 100ms-1

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14
Q

What are the two nervous systems

Explain what they are

A

Nerves carry impulses to and from the rest of the body (Peripheral Nervous system)
Central Nervous system consisting of the brain and the spinal cord

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15
Q

What do the Somatic Nervous system and the Autonomic Nervous System control?

A

Controls conscious actions like walking (somatic)

Controls unconscious actions like altering heart rate (autonomic)

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16
Q

Draw a brain label parts of the brain

A
Should have 
Cerebrum
Hypothalamus 
Pituitary Gland 
Medulla 
Cerebellum 
Spinal Cord 
Corpus Collosum
17
Q

Functions of Pituitary gland

A

Controlled by the hypothalamus, this region releases hormones to stimulate other glands. This region is the connection between the nervous system and the hormonal system

18
Q

Cerebellum function

A

Has folded cortex and is underneath the cerebrum. It is responsible for muscle contraction, posture and balance

19
Q

Medulla oblongta function

A

Found at base of the brain and at the top of the spinal cord. Responsible for the automatic control of heart rate and breathing

20
Q

Hypothalamus function

A

Found in middle of the brain, it is responsible for temperature regulation and produces hormones that influence the pituitary gland

21
Q

Cerebrum function

A

Divided into two hemispheres and has a thin, folded outer layer, it is involved in hearing, learning, and thinking

22
Q

Draw a sensory neurone

A
Axon terminals
Axon 
Cell body in middle 
Dendron 
Dentrites
23
Q
Draw motor neurone 
Cell body with dendrites 
Axon 
Axon terminals 
With myelin sheath
A

Cell body with dendrites
Axon
Axon terminals
With myelin sheath

24
Q

Draw relay neurone

A

Cell body in middle

25
Q

State some structural and functional difference between motor neurone and sensory

A
Motor neurone 
Longer axon 
No dendron 
Cell body is at one end of the neurone 
Cell body is in the brain 
Cell body has dendrites 
Carries nerve impulses away from the spinal cord 
Carries nerve impulse to effectors 
(Make comparison points with sensory neurone)
26
Q

Draw a Schwann cell

Write a paragraph about it

A

Circle with snake around it
Schwann cell wraps itself around the axon
Myelin is composed of lipid and protein and has electrical insulating properties

27
Q

What is a reflex

A

A reflex is a rapid, involuntary, automatic response to a particular stimulus
Involuntary / no conscious decision to respond

28
Q

Explain what a spinal reflex is

Explain what a cranial reflex is

A

A fast automatic involuntary unlearned response to a stimulus
Coordinated by neurones passing to and from the spinal cord (spinal)
A fast automatic involuntary unlearned response to a stimulus
Coordinated by neurones to and from the brain

29
Q

Describe how the blinking reflex is coordinated in response to a puff of air into the eye

A
  1. Stimulus is detected by sensory receptors, around the eyelids
  2. If stimulus is above threshold
  3. Impulses are transmitted to the brain I sensory neurones
  4. Synapse between sensory neurones and relay neurones in the brain
  5. Synapse between relay neurones and motor neurones in the brain
  6. Impulses are transmitted from the brain in motor neurones
  7. To effectors in eyelids which contract to lower eyelid
  8. Impulses travel from the brain to both eyelids so that both respond