Nervous System Flashcards
What are the 4 main functions of neurones?
Sensory, motor, reflex, higher cortical function
What body structures involve voluntary motor function?
Skeletal muscle
What body structures involve involuntary motor function?
Smooth muscle, glands and cardiac muscle
What part of a neuron receives and conducts information towards the cell body?
Dendrites
What part of a neuron receives and conducts information away from the cell body?
Axons
Where in the neuron is the nucleus?
Body
The axon is a nerve fibre carrying what?
Action potentials
The axons of neurons are covered in what?
Myelin sheath to act as an insulator
What is the name for the nerve cell body in the CNS and PNS?
CNS= nucleus PNS= ganglion
What is the name for the bundles of axons in the CNS and PNS?
CNS= tract PNS= nerve
The central nervous system involves what?
Brain and the spinal cord
The peripheral nervous system involves what?
Cranial nerves, spinal nerve and autonomic nervous system
Afferent and efferent neurons are part of what nervous system?
Peripheral
Which of afferents and efferents are motor and which are sensory?
Afferent- sensory
Efferent- motor
Where do afferent neurons take signals?
Towards the CNS
Where do efferent neurons take signals?
Away from the CNS
What nervous system are interneurons part of and what is their function?
CNS- create circuits
What are synapses?
The site of chemical connection between two or more neurones
What happens to an electrical signal (AP) at a synapse?
It becomes a chemical signal (neurotransmitter) and then reverts back to an electrical signal
What nervous system supplies the body wall and external environment?
Somatic nervous system
What nerve system supplies the limbs?
Somatic nervous system
What nervous system supplies glands?
Autonomic nervous system
The floor of the cranial cavity is split into what?
Anterior, middle and posterior cranial fossa
What lobes correspond to the anterior cranial fossa?
Frontal lobe
What lobes correspond to the middle cranial fossa?
Temporal lobe
What lobes correspond to the posterior cranial fossa?
Occipital (and cerebellum)
Where does the spinal cord pass through the base of the skull?
Foramen magnum
When does the brainstem become the spinal cord?
After it passes through the foramen magnum
From superior to inferior, what are the 3 parts of the brainstem?
Midbrain, pons, medulla
After passing through the foramen magnum, where does the spinal cord pass through?
Vertebral canal
How many segments of the spinal cord are there? What are these?
4: Cervical Thoracic Lumbar Sacral/Coccygeal
What are the 2 enlargements of the spinal cord?
Cervical and lumbosacral
How many bilateral pairs of spinal nerves are there?
31
Where does the spinal cord end?
Conus medullaris at L1/2
Where is grey matter found?
Outer area at the cerebral cortex of the brain
What is grey matter full of?
Cell bodies
Where is white matter found?
Inner area of the brain
What does the white matter contain?
Many axons which are myelinated
In the spinal cord, the grey and white matter are found where?
Grey- inner
White- outer
The dorsal grey horn (closer to posterior) of the grey matter in the spinal cord contains what cell bodies?
Sensory
The ventral grey horn (closer to anterior) of the grey matter in the spinal cord contains what cell bodies?
Motor
The cranial and spinal nerves are both what type of nerves?
Somatic
Cranial nerve I?
Olfactory- S
Cranial nerve II?
Optic- S
Cranial nerve III?
Occulomotor- M
Cranial nerve IV?
Trochlear- M
Cranial nerve V?
Trigeminal- B
Cranial nerve VI?
Abducent- M
Cranial nerve VII?
Facial- B
Cranial nerve VIII?
Vestibulocochlear- S
Cranial nerve X!?
Glossopharyngeal- B
Cranial nerve X?
Vagus- B
Cranial nerve XI?
Spinal accessory- M
Cranial nerve XII?
Hypoglossal- M
What are the 3 special sensory cranial nerves?
Optic, olfactory and vestibulocochlear
CNs VI, VII and VIII enter the brain where?
Pontomedullary junction
Where do CNs III and IV enter the brain?
Midbrain
Where does CNV enter the brain?
Pons
Where do CNs IX, X and XII enter the brain?
Medulla
Where does CNXI enter the brain?
Spinal cord
In spinal nerves, are the posterior rootlets sensory, motor or mixed?
Sensory
In spinal nerves, are the anterior rootlets sensory, motor or mixed?
Motor
In spinal nerves, are the posterior rami sensory, motor or mixed?
Mixed
In spinal nerves, are the anterior rami sensory, motor or mixed?
Mixed
Spinal nerves are only located where?
Intervertebral foramina
Spinal nerves are named according to the vertebrae ? it, apart from in the ? region where they are named by the vertebrae ? it
Spinal nerves are named according to the vertebrae above it, apart from in the cervical region where they are named by the vertebrae below it
Which region of the spine contains an extra spinal nerve over its number of vertebrae?
Cervical (7 vertebrae, 8 spinal nerves)
Does the anterior or posterior ramus of a spinal nerve supply the limbs?
Anterior- via a plexus
Where does the T4 dermatome lie?
Male nipple
Where does the T10 dermatome lie?
Umbilicus
What are nerve plexuses?
Networks of intertwined anterior rami
What makes up the cervical plexus and what does it supply?
C1-4 anterior rami- posterior scalp, neck wall, diaphragm
What makes up the brachial plexus and what does it supply?
C5-T1 anterior rami- upper limb
What makes up the lumbar plexus and what does it supply?
L1-L4 anterior rami- lower limb
What makes up the sacral plexus and what does it supply?
L5-S4 anterior rami- lower limb, gluteal region and perineum
Where do sympathetic nerves originate from?
Autonomic centres of the brain
Sympathetic nerves exit the spinal cord with what spinal nerves?
T1-L2 (thoracolumbar)
What do sympathetic nerves travel to?
Sympathetic chains
What do sympathetic nerves need to pass into before they can supply organs?
Splanchnic nerves
How do all parasympathetic axons leave the CNS?
Via cranial nerves III, VII, IX and X and sacral spinal nerves (cranio-sacral)
What supplies all of the organs in the neck, chest and abdomen with parasympathetic axons?
Vagus nerve
What carries parasympathetic axons to the hindgut, pelvis and perineum?
Sacral spinal nerves
What is the sensory innervation of the body wall?
Somatic sensory
What is the sensory innervation of the organs?
Visceral afferents
What is the sensory innervation of the special sensory organs?
Special sensory nerves
What is the motor innervation of the body wall?
Somatic motor
What is the motor innervation of all organs (inc. special sensory)?
Autonomic
What are the sensations felt by the body wall?
Touch, vibration, proprioception, temperature, pain
What will somatic (body wall) pain feel like?
Sharp, stabbing and well localised
How long is the somatic pathway for touch?
3 neurones
What is the primary somatosensory area of the brain?
Parietal lobe (left)
Which of upper and lower somatic motor neurones originate on the opposite side from the movement and which on the same side?
Upper motor neurones- originates opposite side
Lower motor neurones- originate same side
Where do upper somatic motor neurones cross over to the side corresponding to the movement?
Brainstem
Where do lower somatic motor neurones connect?
Skeletal muscle
What is the primary somatomotor area of the brain?
Left frontal lobe
What does paralysed mean?
A muscle without a functioning lower motor neurone- this cannot contract
What would a paralysed muscle show on examination?
Reduced tone
What does spasticity mean?
Muscle has an in tact and working lower motor neurone but the descending control from the brain isn’t working
What would a spastic muscle show on examination?
Increased tone
Is the autonomic nervous system voluntary or involuntary?
Involuntary
What are sensory neurones to organs known as?
Visceral afferents
What are the motor neurones to organs known as?
Sympathetic and parasympathetic nerves
How is visceral pain described?
Dull and achy, poorly localised
Visceral afferents commonly travel with what?
Parasympathetic and sympathetic nerves
What does the sympathetic division of the ANS supply?
All internal organs, body wall organs and arterioles
What is the name for sympathetic innervation of arterioles?
Sympathetic tone
What is the relative size of the pre and post ganglionic sympathetic neuron?
Short preganglionic and long postganglionic
Where does the sympathetic trunk run?
Parallel to the vertebral column
Postganglionic sympathetic axons to the foregut, midgut and hindgut organs come from where?
Prevertebral ganglia
What does the parasympathetic division NOT supply?
Body wall organs or arterioles
What is the relative size of the pre and post ganglionic parasympathetic neuron?
Long preganglionic and short postganglionic
