module 5 - 13.2 neurones Flashcards

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1
Q

what is a neurone/nerve cell?

A

a cell that transmits electrical impulses and communicates with other cells c=via specialised connections called synapses

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2
Q

what is the main component of nervous tissue in all animals (except sponges)

A

a neurone
- plants and fungi do not have neurones

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3
Q

what are the 3 types of neurones?

A

sensory neurone
relay neurone
motor neurone

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4
Q

what is the function of neurones?

A

to rapidly transmit electrical impulses to allow coordination

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5
Q

what is the cell body of a neurone?

A

nucleus, mitochondria and RER to allow protein synthesis, production of neurotransmitters

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6
Q

what are the dendrons of a neurone?

A

transmits electrical impulses TOWARDS cell body, form a branching pattern with smaller dendrites

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7
Q

what is the axon of a neurone?

A

transmits electrical impulses AWAY from the cell body, often very long, narrow cytoplasm covered by plasma membrane with microtubule support

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8
Q

what is nerve tissue?

A

a large bundle of neurones

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9
Q

what is a sensory neurone?

A
  • transmits electrical impulses from receptor cell to brain or motor neurone
  • dont detect stimulus
  • have one dendron that may branch into several dendrites
  • dendron carried impulse to cell body
  • axon carried impulse away from cell body
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10
Q

what is a relay neurone?

A
  • transmits electrical impulses between neurones
  • has central cell body
  • has many short dendrons branching into several dendrites
  • dendrons/dendrites carry nerve impulses towards cell body
  • many axons that branch our
  • axons carry impulses away from cell body
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11
Q

what are motor neurones?

A
  • transmit electrical impulses from relay neurone or sensory neurone to an effector
  • has many dendrites that carry the impulse towards cell body
  • long axon, may have branches at its terminal
  • axon carries impulse away from cell body
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12
Q

what are effectors?

A

muscles or glands

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13
Q

what are myelinated neurones?

A

neurones that have an insulating layer around the axon made from myelin

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14
Q

what is myelin made by when in the PNS?

A

schwann cells when a neurone is in the peripheral nervous system (PNS)

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15
Q

what is myelin made by when in the CNS?

A

oligodendrocytes when the neurone is in the central nervous system (CNS)

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16
Q

what are schwann cells?

A
  • produce many layers of plasma membrane by growing around and around the axon of neurones in the PNS (lipid based myelin sheath)
  • outer layer of schwann cells is called neurilemma
17
Q

what is the role of a schwann cell?

A

allows dead neurones to reform inside the tunnel created by the schwann cell (band of bunger)

18
Q

what are oligodendrocytes?

A
  • perform same function as schwann cells bu =t are found on neurones of the CNS
  • do not have neurilemma as they wrap around multiple axons (up to 50)
19
Q

what is the myslin sheath made from?

A

schwann cells

20
Q

what are the nodes of Ranvier?

A

small gaps between the myelin sheath and where the axolemma is exposed to extracellular space

21
Q

ow?what do the nodes of ranvier allw

A

allows electrical impulse to jump from one node to the next, increasing speed of transmission of impulse
- THIS IS CALLED SALTATORY CONDUCTION

22
Q

what is the charcot-marie-tooth disease?

A
  • group of inherited disorder of nerves
  • characterised by loss of muscle tissue and touch sensation
  • incurable
  • one of the most common inherited neurological disorders
23
Q

what is multiple sclerosis?

A
  • demyelinating disease where myselin sheath of nerve cell axons in the brain and spinal cord are damaged
  • damage disrupts ability of parts of nervous system to transmit signals
  • results in physical, mental and psychiatric problems
  • underlying mechanism is either destruction of immune system or failure of myelin producing cells
  • incurable