Nervous System Flashcards
What r the two anatomical subdivisions of the nervous system?
Central nervous system (CNS)
Peripheral nervous system (PNS)
What does the CNS include? 2 things
Brain
Spinal cord
What nerves does the PNS include? 4 points
All other nerve tissues not within the CNS
Spinal nerves (31 pairs)
Cranial nerves (12 pairs)
Autonomic nerves
Name 3 autonomic nerves
Visceral afferents
Sympathetic nerves
Parasympathetic nerves
What is a neurone?
A nerve cell
What do dendrites do? 2things
Increase SA of cell body
Reach out and communicate with adjacent neurones
What does a myelin sheath do? 2 things
Electrical insulator
Allows rapid transmittance of electrical activity along the axon
Name this structure
Dendrites
Name this structure
Ganglion
Name this structure
Nerve cell body
Name this structure
Myelin sheath
Name this structure
Axon
How many functions can a single nerve fibre carry?
One
What r the 6 different functions that nerve fibres carry?
- Somatic sensory function
- Somatic motor function
- Special sensory function
- Visceral afferent function
- Sympathetic function
- Parasympathetic function
What does somatic mean?
Body wall
What does visceral mean?
Organ
What does afferent mean?
Another word for sensory
What does somatic sensory function do?
Conveys sensory information from the body wall
What does somatic motor function do?
Tells a muscle connected to the body wall to do something
What does special sensory function do?
Tells the brain about a special sensation
(sight, smell, taste, sound or balance)
What does visceral afferent function do?
conveys sensory information from an organ
What does sympathetic function do?
Tells cardiac/smooth muscle to contract or a gland to secrete
What does parasympathetic function do?
Tells cardiac/smooth muscle to contract or a gland to secrete
What is a mixed nerve
Carries 2 or more functional types of nerve fibre to any given region of the body or structure
Name this section of the brain
Right cerebral hemisphere
Name this section of the brain
Cerebellum
Name this section of the brain
Cerebrum
Name this section of the brain
A gyrus
Name this section of the brain
A sulcus
Name this section of the brain
Brain stem
Name this section of the brain
Spinal cord
Name this section of cranial bone
Frontal
Name this section of cranial bone
Temporal
Name this section of cranial bone
Parietal
Name this section of cranial bone
Occipital
Name this lobe of the brain
Frontal lobe
Name this lobe of the brain
Parietal lobe
Name this lobe of the brain
Occipital lobe
Name this lobe of the brain
Temporal lobe
What is the cerebellum responsible for?
Fine motor control
(posture, balance, co-ordination)
What is the occipital lobe responsible for?
Visual processing
What is the parietal lobe responsible for?
Proprioception, sensory information integration
What is the frontal lobe responsible for? 3 things
Motor function
Impulse control
Judgement
What is the temporal lobe responsible for?
Visual memory
Processing sensory input
What is the cerebral neocortex?
The outermost layer of the cerebral hemisphere
Name this part of the brain
Grey matter
Name this part of the brain
White matter
Name this part of the brain
White matter
What is in grey matter?
Full of cell bodies
What is in white matter
Many myelinated axons
In the spinal chord where is the white matter in relation to the grey matter?
White matter is superficial and grey matter is deep
What is the name of CN V?
Trigeminal nerve
What is the name of CN VII?
Facial nerve
Why are they called cranial nerves?
All course through the cranial cavity
Name this structure
Brainstem
Cranial nerves are bilateral, what does this mean?
There is a right and a left one, e.g. left CN I and right CN I
Name this structure
Pons
Name this structure
Midbrain
Name this structure
Medulla oblongata
Name this structure
CN V1, V2, V,3
Trigeminal nerve
Name this structure
CN VII
facial nerve
Name this structure
Spinal chord
Name this structure
Medulla oblongata
Name this structure
Pons
Name this structure
Midbrain
Is the Trigeminal nerve CNV and facial nerve CNVII somatic sensory, somatic motor or mixed fibres?
Mixed
Are there sympathetic axons in cranial nerves?
No
What fibres does each CN V Trigeminal nerve contain?
V1&2: sensory
V3: sensory and motor
What 3 different fibres does CN VII facial nerve contain?
Special sensory, motor and parasympathetic
Why r there foraminae/fissures/canals in the base of the skull
For CNS to pass between the brain and periphery
Name this section of the base of the skull
Anterior cranial fossa
Name this section of the skull cap
Middle cranial fossa
Name this section of the skull cap
Posterior cranial fossa
Superior orbital fissure
Name this foraminae
Foramen rotundum
Name this foraminae
Foramen ovale
Name this foraminae
Internal acoustic meatus
Name this foraminae
Foramen magnum
Why is the middle cranial fossa the most important to a dentist?
The CN V Trigeminal nerve exits the skull here.
Through the superior orbital fissure, Foramen rotundum and Foramen ovale
What does the spinal chord go through to exit the skull?
Foramen magnum
What is the spinal chord protected by?
Vertebral canal
What r the 4 segments of the spinal chord?
Cervical segment
Thoracic segment
Lumbar segment
Sacral/coccygeal segment
What r the 2 enlargements in the spinal chord?
Cervical enlargement
Lumbosacral enlargement
How does the spinal chord connect with the spinal nerves?
Bilaterally
How many spinal nerves does the spinal chord connect to
31 pairs
The spinal chord ends inferiorly at what intervertebral disc level?
L1/L2 intervertebral disc level
Name this segment of the spinal chord
Cervical segment
Name this segment of the spinal chord
Thoracic segment
Name this segment of the spinal chord
Lumbar segment
Name this segment of the spinal chord
Sacral/coccygeal segment
Name this enlargement of the spinal chord
Cervical enlargement
Name this enlargement of the spinal chord
Lumbosacral enlargement
What is the terminal part of the spinal chord called?
Conus medullaris
Name this section of the vertebral canal
Cauda equina
What is the cauda equina?
Lumbar and sacral spinal nerve roots descending into the vertebral canal to there respective intervertebral foraminae
How many pairs of cervical spinal nerves?
8
C1-C8
How many pairs of thoracic spinal nerves?
12
T1-T12
How many pairs of lumbar spinal nerves?
5
L1-L5
How many pairs of sacral spinal nerves?
5
S1-S5
How many pairs of coccygeal spinal nerves?
1
Co
What is the soma?
Body wall
Name this structure
Spinal chord
Name this structure
T4 posterior ramus
Name this structure
Right T4 spinal nerve
Name this structure
Skin
Name this structure
Fascia
Name this structure
Skeletal muscle
Name this structure
right T4 anterior ramus
Name this structure
Parietal pleura
Name this structure
Sympathetic chains
What r the structure included in the soma? 6 things
Neck wall
Chest wall
Diaphragm
Abdominal wall
Pelvic wall
All 4 limbs
Name this structure
Right posterior rootlet
Name this structure
Right posterior root
Name this structure
Posterior rami
Anterior rami
Name this structure
Spinal nerve
Name this structure
Right anterior root
Name this structure
Right anterior rootlet
Name this structure
White matter
Name this structure
Grey matter
Name this structure
Intervertebral Foramen
What type of fibres do posterior rootlets and roots contain?
Sensory fibres
What type of fibres do anterior rootlets and roots contain?
Motor fibres
What type of fibres does the spinal nerve contain?
Mixed
Sensory and motor fibres
Each segment of the body wall is supplied by how many spinal nerves?
Single pair
What does a dermatome map do?
Illustrates which part of the body is supplied by which pair of spinal nerves
Which dermatome is the level of the male nipple?
T4
Which dermatome is the level of the umbilicus?
T10
Where are there dermatomes that contain no posterior rami?
Limbs
The nervous system is subdivided on the basis of function into what 2 things?
Somatic nervous system
Autonomic nervous system
What does the somatic nervous system respond to?
External environment
What does the autonomic nervous system do?
Senses and responds to the Internal environment
Where do the somatic nerves supply?
Soma: body wall
What does the somatic nervous system do?
Senses and responds to external environment
Axons of somatic neurones are found in what?
Spinal nerve branches (named nerves)
What do somatic sensory nerves do? (From 5 things)
Relay sensory information from the skin, parietal pleura, skeletal muscle, bones and joints
What do somatic motor nerve fibres do
Relay information to skeletal muscles to allow us to contract those muscles
Is the somatic nervous system voluntary or involuntary
Voluntary
(NB reflexes)
Is the autonomic nervous system voluntary or involuntary?
Involuntary
What r the two parts of the autonomic nervous system?
Sympathetic: fight or flight
Parasympathetic: rest and digest
What 7 things does the sympathetic part of the autonomic nervous system affect?
Heart
Arterioles
Skin
Lungs
Gut
Pupils
Liver
How does the sympathetic nervous system affect the heart?
Increases heart rate
How does the sympathetic nervous system affect the arterioles?
Dilated or constricts
How does the sympathetic nervous system affect the skin
Makes hair stand on end and produces sweat
How does the sympathetic nervous system affect the lungs
Dilated bronchioles
How does the sympathetic nervous system affect the gut?
Reduces motility / closes sphincters
How does the sympathetic nervous system affect the pupils?
Dilates
How does the sympathetic nervous system affect the liver?
Releases glucose
What don’t have a parasympathetic nerve supply?
Skin and arterioles
What does the parasympathetic part of the nervous system affect? 5 things
Heart
Lungs
Gut
Pupils
Liver
How does the parasympathetic part of the autonomic nervous system affect the heart?
Decreases heart rate
How does the parasympathetic part of the autonomic nervous system affect the lungs?
Constricts bronchioles
How does the parasympathetic part of the autonomic nervous system affect the gut?
Increases motility/opens sphincters
How does the parasympathetic part of the autonomic nervous system affect the pupils?
Constricts
How does the parasympathetic part of the autonomic nervous system affect the liver?
Doesn’t release glucose
What r the 6 steps in the transit of sympathetics from the brain to the organs?
- Action potential arise from autonomic centres in brain
- Pass down spinal chord
- Thoracolumbar flow (T1-L2)
- Enter sympathetic chain
- Pass into 31 pairs of spinal nerves
- Splanchnic nerves to organs
What r located within the lateral horns of T1-L2 spinal chord segments?
Cell bodies for the next sympathetic neurones in the chain
What r the 4 steps for the presynaptic sympathetic neurone to get from the spinal chord to the sympathetic chain?
Blue dotted line
- Anterior roots
- Spinal nerve
- Anterior ramus
- Rami communicans to paravertebral ganglion in sympathetic chain
What happens in the sympathetic chain? 2 things
Synapse within a paravertebral ganglion
Now called postsynaptic sympathetic neurone
What’s the route the postsynaptic sympathetic neurone takes from the sympathetic chain to the stoma?
Back along another rami communicans
Anterior and posterior rami of the spinal nerve, into body wall (stoma)
Name this structure
Rami communicans
All parasympathetic axons leave the CNS via what? 2things
Cranial nerves III, VII, IX & X
Sacral spinal nerves
What is parasympathetic outflow called?
Craniosacral outflow
Where do parasympathetic nerves supply to?
Internal organs
What does the parasympathetic ganglia supply to? 2things
Lacrimal and salivary glands
What does the vagus nerve supply to? 3 things
Organs of the neck, chest and abdomen as far as midgut
What do the sacral spinal nerves carry parasympathetic axons to?
Hindgut, pelvis and perineum
