Neuroscience Anat (CNS Organisation) Flashcards
Somato-sensory = sensory from ____ (conscious/subconscious)
Somato-motor = motor innervation for ____ muscles (voluntary/involuntary)
Viscero-sensory = sensory from ____ (conscious/subconscious)
Viscero-motor (ANS) = motor innervation for ____ muscles (voluntary/involuntary)
Somato-sensory = sensory from SKIN/JOINTS (conscious)
Somato-motor = motor innervation for SKELETAL muscles (voluntary)
Viscero-sensory = sensory from ORGANS (subconscious) except visceral pain is conscious
Viscero-motor (ANS) = motor innervation for SMOOTH muscles AND GLANDS (involuntary)
In brain parenchyma, white matter inside/outside, grey matter inside/outside
State the contents of white and grey matter in brain
In brain parenchyma, white matter inside, grey matter outside
WHITE MATTER:
- myelinated axons
GREY MATTER:
- cerebral cortex
- thalamus
- basal ganglia
State the definition of nuclei and ganglion
nuclei = aggregation of neuronal cell bodies in CNS
ganglion = aggregation of neuronal cell bodies in PNS
State the total number of pairs of spinal nerves.
State the number of spinal nerves for each type of vertebrae.
total of 31 pairs
cervical - 8
thoracic - 12
lumbar - 5
saccral - 5
coccygeal - 1
State the number of cranial nerves.
Name each cranial nerve
12 pairs of cranial nerves
CN I - olfactory N
CN II - optic N
CN III - oculomotor N
CN IV - trochlear N
CN V - trigeminal N
CN VI - abducens N
CN VII - facial N
CN VIII - vestibulocochlear N
CN IX - glossopharyngeal N
CN X - vagus N
CN XI - spinal accessory N
CN XII - hypoglossal N
State the function of nerve cells/neurons
State the flow of neuronal information through nerve.
FUNCTIONS:
1. ability to initiate and conduct electrical impulses
2. ability to secrete and transmit neurotransmitters or modulators
FLOW OF INFORMATION:
dendrites –> cell body –> axons –> synapse
State the 2 forms of adaptations the nerve cells/neurons can undergo
- increased number of mitochondria - supply more energy to facilitate efficient communication
- increased number of dendrites - facilitate rapid communication due to increased surface area contact with other neurons to receive electrical impulses
How do neurons transmit neuronal information so quickly
Signal jumps from node of ranvier to the next across the myelin sheaths (increasing speed of conduction)
Recap the 3 types of neuroglial cells in CNS, state the 2 types of glial cells in PNS
NEUROGLIAL CELLS (CNS)
1. ASTROCYTES - control BBB
2. OLIGODENDROCYTES - myelinate CNS axons
3. MICROGLIA - phagocytic function
GLIAL CELLS (PNS)
1. SATELLITE CELLS - support and protect neurons
2. SCHWANN CELLS - myelinates PNS axons
State the 2 types of neurons commonly found. State the type of conduction that occurs in each neuron.
- MYELINATED NEURON
- saltatory conduction
- activation in the nodes of Ranvier (faster conduction) - NON-MYELINATED NEURON
- continuous conduction
- activation along entire length of axon (slower conduction)
activation occurs through voltage-gated sodium channels
State the vertebral level where the spinal cord ends.
Name the extension at that level.
State the common presentation of any pathologies related.
Spinal cord ends at cona medullaris (L1-L2) level.
Cauda equina extends from cona medullaris.
Relevant pathology = cauda equina syndrome
- Cauda equina is PNS –> downgoing plantars + absent reflexes
- Lower back pain
- Leg pain
- Paralysis of muscles in thigh and legs
- Incontinence
State the relevant horns involved in
1. somato-sensory
2. viscero-sensory
3. somato-motor
4. viscero-motor (ANS)
(1) SOMATO-SENSORY AND (2) VISCERO-SENSORY = dorsal horn via DRG
(3) somato-motor = ventral horn directly to skeletal muscles
(4) viscero-motor = lateral horn to synapse onto autonomic ganglia –> post-synaptic neuron brings information to smooth muscles and glands
Dermatomes are the ____ of ____ innervation on the ____ for one particular ____.
Myotome is the ____ that one particular ____ supplies.
Dermatomes are the AREAS of SENSORY innervation on the SKIN for one particular SPINAL ROOT/SPINAL NERVE.
Myotome is the MUSCLES (MOTOR INNERVATION) that one particular SPINAL ROOT/SPINAL NERVE supplies.
State the steps involved in the reflex arc.
- receptors respond to stimulus
- afferent sensory neuron carries impulses to the CNS
- integration of information in CNS (monosynaptic / polysynaptic)
- efferent motor neuron carries impulses to effector
Name the cranial nerves that have parasympathetic (ANS) function.
3,7,9,10
CN III - oculomotor N –> IOM (ciliary muscles and sphincter pupillae)
CN VII - facial N –> glands of face except parotid gland (lacrimal, submandibular, sublingual)
CN IX - glossopharyngeal N –> parotid gland
CN X - vagus N –> to distant organs
State the pathways affected by anterior cord syndrome. State the common causes of this syndrome.
State the resultant impact of the syndrome.
AFFECTED PATHWAYS
1. spinothalamic tract
COMMON CAUSES
1. anterior spinal artery occlusion –> spinal infarct
RESULT:
1. loss of pain pathways
2. loss of temperature
State the pathways affected by posterior cord syndrome. State the common causes of this syndrome.
State the resultant impact of the syndrome.
AFFECTED PATHWAYS:
1. dorsal column medial lemniscus
COMMON CAUSES:
1. b12 deficiency
2. syphillis - tabes dorsalis
RESULT:
1. loss of proprioception
2. loss of vibrations
State the common causes of
1. anterior cord syndrome
2. posterior cord syndrome
3. entire cord syndrome
- anterior cord syndrome - anterior spinal artery occlusion leading to spinal infarct
- posterior cord syndrome - b12 deficiency, syphillis (tabes dorsalis)
- entire cord - transverse myelitis
State the function of each ascending (somato-sensory) pathway
(1) SPINOTHALAMIC
- crude touch and pressure
- pain and temperature
(2) DORSAL COLUMN MEDIAL LEMNISCUS
- fine touch
- vibrations
- pressure
- conscious proprioception
(3) SPINOCEREBELLAR
- unconscious proprioception
State the function of each descending (somato-motor) pathway
(1) CORTICOSPINAL (PYRAMIDAL) TRACT
- voluntary, discrete and skilled movements
(2) EXTRAPYRAMIDAL SYSTEM (POSTURAL PATHWAYS)
- muscle tone
- posture and movement
State the common presentations of UMN and LMN lesions.
UMN LESION
- hyperreflexia (brisk reflexes)
- hypertonia
- spasticitiy
- rigid paralysis
- babinski’s sign
- upgoing plantars
LMN LESION
- hyporeflexia / areflexia (absent reflexes)
- hypotonia
- flaccid paralysis
- muscular atrophy
- fasciculations
State the 2 spinal (visceral-motor) pathways
- sympathetic - thoracolumbar outflow
- parasympathetic - craniosacral outflow
State the substances involved in the preganglionic and postganglionic synapse of the SYMPATHETIC and PARASYMPATHETIC PATHWAYS
SYMPATHETIC
- Preganglionic - ACh
- Postganglionic - NA, ACh for sweat glands (adrenergic nerves)
PARASYMPATHETIC
- Preganglionic - ACh
- Postganglionic - ACh (cholinergic nerves)
Recap the 4 cranial nerves that have parasympathetic supply. State the post-synaptic ganglion for each cranial nerve.
CN III (oculomotor N) - ciliary G -> IOM (sphincter pupillae, ciliary body)
CN VII (facial N) - pterygopalatine G + submandibular G -> glands of face (lacrimal, submandibular, sublingual)
CN IX (glossopharyngeal N) - otic G - parotid gland
CN X (vagus N) -> distal organs of the body
State the structures that make up the limbic system.
State the functions it supports.
STRUCTURES:
- hippocampus
- amygdala
- anteiror thalamic nuclei
- limbic cortex (cingulate gyrus)
FUNCTIONS
- emotion
- behaviour
- long term memory
- olfaction
