Nerve And The Brain Flashcards

1
Q

What are the main functions of the Nervous System?

A

Master controlling and communicating
Monitors internal and external environments
Integrates sensory inputs and motor commands
Coordinates involuntary and voluntary responses

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2
Q

What are the two divisions of the Nervous system?

A

Central nervous system

Peripheral nervous system

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3
Q

What is the central nervous system?

A

Command centre

Composed of the brain and spinal cord

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4
Q

What is the peripheral nervous system?

A

Composed of all nerves that extend from the CNS
made of motor and sensory nerves
Further subdivided into cranial and spinal nerves
Produces the information, then processed by the CNS and a response indicated by the peripheral

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5
Q

What are Lower motor neurons?

A

Neurones with cell bodies in the spinal cord or brain stem whose axons directly innervate skeletal muscle
- peripheral nerves

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6
Q

What are Upper motor neurones?

A

Neurones that transmit information from brain to lower motor neurones and interneurons in the brain stem and spinal cord
- central nerves

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7
Q

Describe peripheral nerves

A

Take information from the spinal cord to the muscles
Sensory info goes into the spinal cord and motor comes out
These nerves have the ability to mend and repair them selves

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8
Q

What are the two types of peripheral nerves?

A

Cranial

Spinal

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9
Q

Describe cranial nerves

A

Carry info to and from the brain
12 pairs serving the head and neck
Number 10 however supplies the heart lungs and gastrointestinal - known as the Vagus nerves
Number 7 supplies the face

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10
Q

Describe spinal nerves

A

Information to and from the spinal cord
31 pairs named according to the point at which they leave the spinal cord
Some can form plexi - which are areas where certain nerves combine at the spinal canal

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11
Q

What is the autonomic nervous system? What are the 2 systems within it?

A

An unconscious system
Sympathetic- emerges from the thoracic and lumbar spine. Involves the flight or fight response. Causes increase in HR, BR, Blood pressure etc.
Parasympathetic- emerges from the cranial and sacral parts of the spinal cord. Slows all responses and rates down.

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12
Q

What is the structure of a nerve?

A

Carry both sensory and motor fibres
Whole nerves are surrounded by a connective tissue membrane called the Epineurium.
Bundles of afferent and efferent neurones are surrounded by Perineurium.
Each individual neurone is covered by Endoneurium.

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13
Q

What structures do highly specialised nerve cells contain?

A
Dendrites 
Cell body 
Axon 
Axis Hillock 
Synapse
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14
Q

Describe dendrites

A
Can contain 1000s 
Extend from the cell body’s 
Extensions of plasma membranes 
Receive incoming impulses from sensory receptors 
Bring info to the cell body
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15
Q

Describe the cell body

A

Contain the nucleus and the cell organelles needed for the neurone to carry out its function.
Such as Golgi apparatus, mitochondria

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16
Q

Describe the axon

A
Long cytoplasmic process 
Capable of conduction action potentials 
Only one, but have collateral branches and many terminal branches 
May be covered in a myalin sheath 
Can be meters long and very thick
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17
Q

What is a myelin sheath?

A

A fatty substance produced by Schwann cells in the PNS and oligodendrocytes in the CNS.

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18
Q

Describe axon hillocks

A

Only place where an action potential can be initiated

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19
Q

Describe a synapse

A

The axons end in a synapse
There terminals contain 1000s of vesicles contain neurotransmitters
When an AP reaches the synapse, these vesicles fuse with the membrane and empty the contents into the synaptic cleft.
These then diffuse across and bind to receptors on the post synaptic membrane, passing the impulse on to the next neurone or muscle.

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20
Q

What is Neuroglia and where is it found?

A

Found in the CNS and PNS
It’s a nerve glue
Provides support, insulation and protection
It’s cells lie around and between the neurones
Provides solidity
Contribute to 50% of the Nervous system weight

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21
Q

What are 3 other cells located in the CNS?

A

Astrocytes
Microglia
Oligocendrocytes

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22
Q

What are astrocytes?

A

Connect neurones to blood vessels

Filter blood, preventing damaging substances from entering the neurones of the brain.

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23
Q

What are mircoglia?

A

Additional immune cells

Like phagocytes, to remove debris

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24
Q

What are oligodendrocytes?

A

Produce myelination in the CNS
Can supply multiple segments of axon for multiple neurones
Protect them

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25
Q

What are 2 other types of cells found in the PNS?

A

Satellite

Schwann

26
Q

What are satellite cells?

A

Function is unclear
Have some role in providing nutrients and structure and support.
Also initiating repair to damaged neurones.

27
Q

What are Schwann cells?

A

Produce myelin
This speeds up conduction of an impulse
Wraps around one axon multiple times
Only in the PNS
There are gaps between each Schwann cell
Known as nodes of ranvier
Help to speed up conduction - allow the impulse to ‘jump’

28
Q

What is the neurolemma?

A

Located in Schwann cells in the PNS
Important for regeneration of neurones
Provides structure to allow for repair

29
Q

What is a neurones resting potential?

A

-70 mv

30
Q

How is the resting potential maintained?

A

By the exclusion of sodium ions from the cell and the influx of potassium ions into the cell.

31
Q

What is the presence of a membrane potential called?

A

Polarisation

32
Q

What is the All or Nothing Law?

A

If a stimulus is produced and the threshold is reached then an action potential will be generated.
If a stimulus is produced but threshold not met, no AP is produced.
Once the AP starts it continues without fail.

33
Q

What are the two types of summation?

A

Spatial

Temporal

34
Q

What is spacial summation?

A

AP can be triggered in a narrower from one or more presynaptic neurones where many short signals arrive at multiple dendrites simultaneously.

35
Q

What is temporal summation?

A

A high frequency of action potentials arrive in the presynaptic neurone synapses which can trigger the action potential at the post synaptic.

36
Q

What is is called when an impulse jumps from one node of ranvier to the other down a myelinated neurone?

A

Saltatory conduction

37
Q

What are some neurotransmitter examples?

A

Acetylcholine - excitatory found at neuromuscular junctions
Norepinephrine - excitatory found at arousal synapses and sympathetic nervous system synapses
Dopamine - regulates fluidity of movement
Serotonin - sensory perception of mood
GABA - inhibitor affects in the brain

38
Q

What occurs to damaged neurones in the CNS?

A

Limited/no ability to repair
Difficult for re growth
Damaged astrocytes quickly heal by scar tissue and release chemicals but this blocks atonal re-growth
Neuroglia inhibit growth

39
Q

What occurs to damaged neurones in the PNS?

A

Chromatolysis - occurs shortly after axon damage within 24-48 hours. Cell body swells.
Wallerian degeneration - distal portion of axon degrades and myelin sheath degrades
Wallerian regeneration - neurolemma forms guiding tube for axon to re grow down. Schwann cells proliferate and release fright factors to encourage axons growth.
Schwann cells then remyelinate the neurone

40
Q

What types of damage can occur to a neurone?

A

Compression - axon and neurolemma will still be intact
Crush - axon broken but neurolemma intact
Severed nerve - axon and neurolemma cut

41
Q

What types of injury can you get from nerves?

A

Transient ischaemia- brief neurological dysfunction caused by loss of blood flow in the brain, spinal cord. Without tissue death.
Neurapraxia - PNS. Temporary loss of motor and sensory function due to blockage of nerve conduction.
Neurotmesis - Both the nerve and nerve sheath are disrupted, nerve will need to be sewn back together.

42
Q

What are the different sections of the brain and what are their contents?

A

Cerebrum
Diencephalon - Thalamus and hypothalamus
Brain stem - Medulla, Pons, Mid Brain
Cerebellum

43
Q

Describe the structure of the cerebrum

A

Divided into two hemispheres by a longitudinal fissure
Outer layer composed of grey matter = cerebral cortex
- where the cell bodies lie
- basal ganglia are found
Inner layer composed of white matter
- all axons are located
- association fibres - connect areas in the same hemisphere
- corpus callosum - large area behind the left and right brain, connect the each side of our bodies with each side of our brains
- internal capsule - between thalamus and globus pallidus in the basal ganglia. Where your ascending and descending pathways are

44
Q

How many lobes are in the cerebrum and what are they called?

A
4 lobes 
Frontal lobe
Temporal lobe
Parietal lobe 
Occipital lobe
45
Q

What functions is the frontal lobe associated with?

A

Control of behaviour and movement
Personality and emotion
Memory

46
Q

What important structure does the frontal lobe contain?

A

The primary motor cortex.
Located at the back of the frontal lobe
Initiates and controls voluntary movement
Arranged in a Homunculus
It’s ore motor cortex is also there
Controls initiation and planning of movement

47
Q

What is Broca’s area?

A

Located to the left hemisphere of the frontal lobe
Controls movement of speech and production of words
Sends impulses to the motor cortex
Damage will cause Expressive Dysphasia.

48
Q

What functions are associated with the Parietal lobe? What important feature does it contain?

A

Interpretation of somatic sensation
Contain the sensory cortex
Responsible for awareness - joint, muscle, skin, tendons, receptors etc.
Spatial and body awareness
Contain a homunculus
Hyper sensation, alerted sensation or loss of sensation can occur with damage

49
Q

What functions are associated with the Temporal lobe?

A

Sits just above your ears
Involves the interpretation of speech
Such as sounds, pitch and rhythm

50
Q

What is Wernickes area?

A

Determines if sound is speech, music or noise
Translates words into thoughts
A problem is Receptive Dysphasia which can occur due to damage - trouble with interpretation

51
Q

What functions are associated with the Occipital lobe?

A

At the back of the brain
Interpretation of visual input
Interprets light and dark, shapes, movements of objects and colour
Relates last visual experiences with recognition and evaluation

52
Q

What is the brain stem composed of?

A

Mid brain
Pons
Medulla
- all sensory and motor pathways go up and down the brain stem
Contains vestibular nuclei that are responsible for where our head is in space.

53
Q

Functions and properties of the brain stem

A

Connects with the internal capsule
Decoration of the Pyramids occurs in the Medulla - where ascending and descending pathways cross over.
Non Conscious control
Important confirm centres are located here such as cardiac, respiratory

54
Q

What does the diencephalon consist of?

A

Thalamus and hypothalamus

55
Q

Describe the thalamus

A

Aka. Sensory replay station
Executive assistant for sensory cortex
All sensory information synapses in the thalamus before going up the sensory cortex in the front of the parietal lobe

56
Q

Describe the hypothalamus

A

Regulates homeostasis through influence on the autonomic Nervous system and pituitary gland

57
Q

What is the Limbic System?

A

Controls information on emotions and emotional responses to a given situation.
Plays a role in memory and linked to the sense of smell
Links memory and events between sense of smell

58
Q

What structures are found in the Limbic system?

A

Hippocampus - responsible for memory of event, people, place etc.
Amygdala - responsible for emotions, particularly anger
Cingulate gyrus - helps to regulate emotion and pain

59
Q

What is the basal ganglia? What are some of its structures?

A

Comprised of a group of structures that regulate and initiate movements and posture
Strongly connected to other motor areas in the brain.
Link the thalamus with the motor cortex
Contain the Ssbutancia Nigra - nucleus in the midbrain. Where a lot of dopamine neurones originate.

60
Q

What are the functions of the Cerebellum?

A

Right at the back inferior part of the brain
Produces smooth, coordinated movements and balance
Communicates with Pons
Coordination and refining movements
Non conscious

61
Q

Strokes can cause damage in all parts of the brain. What are some symptoms?

A
Sensory deficit 
Speech and hearing deficit 
Behaviour deficit 
Sight deficit 
Emotions and memory deficit 
Coordination and balance deficit