Nervous System Flashcards
What do neutrons consist of?
Dendrites
Body
Myelin sheath
Axon
What are Nodes of Ranvier?
Spaces between myelin sheath
Which, the CNS or PNS, typically has multiple nerve fibres surrounded by one myelin sheath and which is there usually only one nerve fibre?
CNS - multiple
PNS - single
What makes up the CNS?
Brain and spinal cord
What makes up the PNS?
Spinal nerves, cranial nerves, autonomic nervous system
Afferent neutrons are signals towards the __
CNS
Efferent signals are signals away from the __
CNS
Interneurons, relay and created circuits in the ___?
CNS
What is a synapse?
Site of chemical communication between 2 or more neurones
Chains or neurones usually are less than or equal to _ neurones in length
3
What does the somatic nervous system supply?
Body wall and external environment
What does the autonomic nervous system supply=
Visceral motor system and internal environment
What is the occipital lobe concerned with?
Vision and sight
What is the temporal lobe concerned with?
Speech production
Listening
Comprehension
Emotion
What is the frontal lobe concerned with?
Emotive planning
Conscience
Decisions
What is the parietal lobe concerned with?
Integration
Sensing
What is the cerebral neocortex?
Outermost layer of the cerebral hemispheres
What doe the cerebral neocortex consist of?
Gyri and sulci
The brain stem exits the cranial cavity via the?
Foramen magnum
The floor of the cranial cavity is split into?
Anterior middle and posterior cranial fossa
Which lobe is the anterior fossa associated with?
Frontal lobe
Which lobe is the middle cranial fossa associated with?
Temporal lobe
Which lobe is the posterior cranial fossa associated with?
Occipital lobe and cerebellum
What are the three parts of the brain stem?
Midbrain
Pons
Medulla oblongata
What is the role of the midbrain?
Vision and hearing
Which part of the brain stem communicates with the cerebellum?
Pons
Which part of the brainstem becomes the spinal cord once is leaves the cranial vault via the foramen magnum?
Medulla oblongata
What are the 4 segments of the spinal cord?
Cervical
Thoracic
Lumbar
Sacral/Coccycgeal
What are the 2 enlargements of the spinal cord?
Cervical
Lumbo-sacral
What are the enlargements of the spinal cord?
Thickening of the spinal cord to accommodate increased nerve supply limbs to the limbs
Where does the spinal cord end?
Conus medullaris at L1/L2 intervertebral disc level
Where does the vertebral column end?
Cauda equina
What is the grey matter of the brain?
Outer area full of cell bodies in the cerebral cortex of the brain
What is the white matter of the brain?
Inner area containing many axons - myelinated to give white appearance
Myelinated and unmyelinated nerve fibres come together in connective tissue layers called?
Endoneurium
Endoneurium is collected together in the?
Perinueium
Perineurium is surrounded by blood vessels and fibrobfatty tissue which is all surrounded by?
Epineurium
Spinal nerves are only located within?
Intervertebral foraminae
Posterior rootlets and roots are?
Sensory
Anterior rootlets and roots are?
Motor
Spinal nerves are?
Mixed
Posterior and anterior rami are?
Mixed
How many cervical spinal nerves are there?
8
Where is cervical spinal nerve 8?
Between C7 and T1
Besides the cervical, the spinal nerves are named according to the vertebrae ______ it
above
How many thoracic spinal nerves are there=
12
How many lumber spinal nerves are there?
5
How many sacral spinal nerves are there?
5
How many coccygeal spinal nerves are there?
1
Each pair of spinal nerves supplies one strip of body wall. Which rami supplies the posterior paramedian aspect?
Posterior rami
Which rami supplies the lateral and anterior segments and the posterior paralateral aspect?
Anterior rami
What is a dermatome?
Area of skin supplied both by th anterior and posterior rami of a spinal nerve
Where is T4 dermatome?
Male nipple
Where is the T1 dermatome?
Umbilicus
What is a nerve plexus?
Network of intertwined anterior rami
Which spinal nerves are part of the cervical plexus?
C1-C4 anterior rami
What does the cervical plexus supply?
Posterior scalp, neck wall and diaphragm
Which spinal nerves are involved in the brachial plexus?
C5-T1 anterior rami
What does the brachial plexus supply?
Upper limb
Which spinal nerves are involved in the lumbar plexus?
L1-L4 anterior rami
What does the lumber plexus supply?
Lower limb
Which spinal nerves are involved in the sacral plexus?
L5-S4 anterior rami
What does the sacral plexus supply?
Lower limb
Gluteal region
Perineum
Where do sympathetic nerves originate from in the brain?
Autonomic centres
Where does sympathetic outflow exit the spinal cord?
between T1 and L2
Which part of the spinal cord has lateral horns for cell bodies of the sympathetic neurones in the chain?
T1 - L2
Sympathetic axons within the spinal nerve anterior or posterior ramus pass into _____ nerves to eventually supply organs
splanchnic
From the anterior/posterior rami the impulse travels t other paravertebral ganglion of the sympathetic trunk via the?
Rami communicans
All parasympathetic axons leave the CNS via?
CN III, VII, IX and X and sacral spinal nerves
Where does cranio-sacral parasympathetic outflow go?
Internal organs
Parasympathetic ganglia in the head head to which glands=
Lacrimal (tear duct)
Salivary
The vagus nerve supplies the organs of the neck chest and?
Abdomen (as far as the midgut)
Sacral spinal nerves ‘carry’ parasympathetic axons to the?
Hindgut, pelvis and perineum
Both the organs and special sense organs receive their motor supply from?
the Autonomic nervous system (sympathetic/parasympathetic nerves)
Sensory supply to the organs is?
Visceral afferent
For special sensory organs the supply is from?
Special sensory nerves
Somatic sensation is detected by which receptors?
Mechanoreceptors
Thermoceptors
Nociceptors
What is the somatic sensory pathway?
Sensory receptor to dorsal horn;
synapse in the CNS onto a 2nd order neurone and tract up in white matter and then synapse in the thalamus (3rd order neurone)
goes to the appropriate region in the cerebral cortex (specific to the part of the body wall stimulated)
The sensory homunculus shows?
Areas of the primary somatosensory part of of cerebral cortex where sensations from each body wall structure reach consciousness - size indicates sensitivity
Upper motor neurones originate from _____ side from the movement? The axons ___ the brainstem
opposite
cross
Lower motor neutrons originate from the ____ side as movement
same
Lower motor neurones connect to?
Skeletal muscle
Where do motor APs originate for planned movement?
Frontal lobe
Which frontal lobe originates the AP for contraction of a right sided skeletal muscle to make a movement?
Left frontal lobe
Where is the primary somatomotor area in the brain?
Frontal lobe
APs conducted via an upper motor neurones cross in the?
Brainstem
Outline the course of an AP created in the left primary somatosensory cortex?
AP conducted via UMN axon Cross in brainstem Reach anterior horn of L3 spinal cord UMN synapse with LMN stimulating AP Continues along axon to L3 spinal nerve AP continues to (either) anterior ramus (often weave through lumber plexus) AP reaches NMJ of supplied muscle
Spinal reflexes miss out the pathway to the __ resulting in ______, extremely rapid response
brain
involuntary
Deep tendon reflexes prevent?
Outstretching of tendons
How is jerking prevent in reflexes?
Brain send down inhibitory signals (descending controls) to prevent jerking
What is paralysis?
Muscle without functioning lower motor neurone
Can’t contract, decreased muscle tone
What is spasticity?
Muscle has intact LMN but descending controls from the brain don’t work
More jerkily
increase muscle tone
What is the effect of sympathetic stimulation (fight/flight response)?
Pupils dilate HR increases Bronchioles dilate GIT motility decreases and sphincters close Glucose released from liver into blood Adrenaline/Noradrenaline released Arterioles diate in scelta muscle and constrict Hair on skin stand up Sweat produced
What type of outflow do sympathetic nerves have?
Thoracolumbar
Sympathetic nerves exit the spinal cord and travel to _______ running the lengths of the vertebral column
Sympathetic chains
Sympathetic nerves have a longer __ganglionic neurone the ___ganglionic
post-
pre-
Autonomic fibres descend from the brain to the lateral horns of the?
Spinal cord
Sympathetic axons leave the signal cord in?
Anterior rootlets/roots
Anterior rootlets/roots become _________- within spinal nerve anterior or posterior ramus?
Sympathetic axons
Via which structure is the anterior or posterior ramus connect to the paravertebral ganglion of the sympathetic trunk?
Rami communicans
What are the 3 routes of sympathetic outflow?
- Synapse and postganglionic axon travel via anterior/posterior rami to target
- Synapse and postganglionic axon travel along sympathetic chain to target
- Don’t synapse and travel through the ganglion to form splanchnic nerve then in pre vertebral ganglion
Post ganglionic axons to fore, mid and hangout organs originate from?
Prevertebral ganglia and sympathetic supply supply to adrenal medulla
The parasympathetic division of the ANS supplies the same internal organs as sympathetic but doesn’t supply?
Body wall organs and arterioles
Parasympathetic Division is responsible for?
Rest and digest: return to homeostasis
The preganglionic neurone for parasympathetic is ___ than the post-ganglinoic
longer
Parasympathetic ganglia lie close to or even on the wall of the?
Target organ
