central nervous system Flashcards
(78 cards)
1
Q
what does the central nervous system consist of?
A
- brain
- spinal cord
2
Q
how is information relayed to the CNS?
A
- by afferent neurones in peripheral nervous system
3
Q
what does the CNS do with the information?
A
- collects and processes it
- stores info and responds when appropriate
4
Q
how and where is information transported out CNS to?
A
- to effector cells
- by the efferent neurones of the peripheral nervous system
5
Q
what is the brain divided into?
A
- two hemispheres
(left and right)
6
Q
what does the left hemisphere control?
A
- logic
- numbers
- language
7
Q
what does the left hemisphere process?
A
- sensory and motor pathway for the right side of the body
8
Q
what does the right hemisphere control?
A
- creativity
- imagination
- rhythm
9
Q
what does the right hemisphere process?
A
- sensory and motor pathways of left side of body
10
Q
what are the two hemispheres joined by?
A
- neural bridge of nerve fibres known as corpus callosum
- allows communication
11
Q
where is the corpus callosum seen?
A
- superiorly by looking down through deep fissure between two halves
- medial view by separating the cerebral hemispheres
12
Q
what are the different components of the brain?
A
- forebrain
- midbrain
- hindbrain
13
Q
what does the forebrain consist of?
A
- cerebrum
- thalamus
- hypothalamus
14
Q
is the midbrain divided into more areas?
A
- no
15
Q
what does the hindbrain consist of?
A
- cerebellum
- pons
- medulla
16
Q
what does the brainstem consist of?
A
- midbrain
- pons
- medulla
17
Q
what is the function of the midbrain?
A
- controls higher functions
- controls eye movement
- controls auditory system
18
Q
what is the function of the medulla?
A
- controls very basic, life sustaining functions
- eg. breathing, heart rate
19
Q
what does the pons have roles in?
A
- consciousness
- posture
20
Q
what does the cerebellum consist of?
A
- two mounds of folded tissue posterior to brainstem
21
Q
what is the cerebellum connected to the brainstem by?
A
- three peduncles (bands of neurones resembling a stalk)
22
Q
what is the role of cerebellum?
A
- motor functions
- motor learning (riding bike)
23
Q
what does the cerebellum receive inputs from?
A
- ascending sensory pathways from body
- descending motor pathways from cerebrum
- other info from brainstem
24
Q
what is the thalamus?
A
- relay point
25
what happens at the thalamus?
- all inputs to cerebrum synapse before ascending to cerebral cortex
26
what is the main function of the hypothalamus?
- homeostasis
27
what does the hypothalamus directly control?
- blood pressure
- body temperature
- fluid and electrolyte balance
- body weight
28
what body processes are controlled by hypothalamus?
- heart rate
- vasoconstriction
- digestion
- sweating
29
where does the autonomic nervous system originate?
- hypothalamus via inputs to medulla
30
what does stimulation of pituitary gland cause?
- release of hormones
31
what does most of the volume of cerebral hemispheres consist of?
- white matter
32
what does the white matter contain?
- axons
33
what do the axons connect?
- cell bodies found in grey matter
34
what does the grey matter make up?
- cerebral cortex
35
where does grey matter exist?
- surface of hemispheres
36
what does the cerebral cortex control?
- intelligence
- personality
- interpretation of sensory impulses
- motor function
- planning and organisation
- touch sensation
37
what is the sulci?
- inholdings of brain
- mark boundary of different functions
38
what is the gyri?
- sticky out bits between sulci
- areas of functional grey matter
39
what are the key structures of the brain?
- frontal lobe
- parietal lobe
- temporal lobe
- occipital lobe
- central sulcus
- pre central gyrus
- post central gyrus
- lateral fissure
- corpus callosum
- Pareto-occipital sulcus
40
what is the primary motor complex?
- pre central gyrus
41
what is the somatosensory cortex?
- post central gyrus
42
what is the function of the frontal lobe?
- integrated brain functions (planning)
- emotional responses
43
what is the function of the parietal lobe?
- movement
- orientation
- recognition
44
what is the function of the occipital lobe?
- involved with visual cortex
45
what is the function of the temporal lobe?
- integrating sound and speech
- forming memories
46
what is the function of the pre-central gyrus?
- location of primary motor complex
- movement
47
what is the function of the post-central gyrus?
- location of primary somatosensory cortex
- touch
- pain
- temperature
- proprioception
48
what is the CNS covered by?
- meninges
49
what is the purpose of the meninges?
- layer of tissues that separates CNS from rest of body
50
what 3 layers is the meninges made up of?
- pia mater
- arachnoid mater
- dura mater
51
what is the Pia mater?
- adherent to brain
- dips down into sulci of brain
52
what is the arachnoid mater?
- middle layer
53
what is the dura mater?
- outermost
- very tough
54
what is the CNS bathed in within the meninges?
- cerebrospinal fluid (CSF)
55
what does the combination of CNS and meninges allow?
- cushioning of brain
- protection of damage
56
what is CSF produced by?
- specialised epithelium (choroid plexus)
- lines cavities within brain known as ventricles
57
what does the choroid plexus actively secrete?
- components of blood plasma into ventricles
58
what does the choroid plexus produce?
- clear fluid
- lower in proteins, cells and ions than the plasma
59
what does CSF have a higher concentration of than in plasma?
- sodium ions
- chloride ions
- magnesium ions
60
why does CSF have high conc of these ions?
- chemicals are actively transported by epithelium into the CNS
61
what does the CSF circulate through?
- ventricles (cavities) within brain before exiting onto surface of brain
- to bathe brain and spinal cord
62
where is CSF reabsorbed?
- into venous circulation at arachnoid granulations
63
what are the ventricles of the brain?
- spaces or cavities within brain
- linked by passageways called aqueducts
64
what do the aqueducts allow?
- CSF to circulate through the brain and open onto surface of CNS
65
what is the lateral flow of the CNS?
lateral ventricles ->
inter ventricular foramina -> third ventricles ->
cerebral aqueduct ->
fourth ventricle ->
median/lateral apertures ->
central canal
66
what is the spinal cord covered with?
- meninges
67
what does the CSF surround?
- spinal cord
68
where does the CSF also flow through?
- central canal that runs through centre of the cord
69
where does the spinal cord terminate in adults?
- L1
70
what does the spinal cord contain below L1?
- spinal nerves
- descend within meninges util they exit at their vertebral level
71
what is the caudal equina?
- nerves within meninges
- inferior to termination of spinal cord
72
what is lumbar puncture/spinal tap procedure?
- CSF can be removed from this space with a needle with minimal risk of damaging nerves
73
what happens if a needle in inserted below L1?
- spinal nerves can float away
74
what happens if needle is inserted above L1?
- risk of piercing the spinal cord
75
what layers does the needle pass through to reach the CSF?
- skin
- subcutaneous tissue
- supraspinous ligament
- interspinous ligament
- ligamentum flavum
- extradural space
- dura mater
- arachnoid mater
- subarachnoid space (where CSF is found)
76
what is the fluid removed to test?
- the health of the CNS
77
what would indicate an infection like meningitis?
- increased levels of white blood cells
78
what could indicate brain haemorrhage or stroke?
- increased levels of red blood cells
