Intro to the nervous system Flashcards
(19 cards)
How is the nervous system divided?
CNS
PNS
- Sensory
- Motor
- Autonomic
- Somatic
Sensory = Afferent
Motor = Efferent
What are the regions of the brain?
Frontal
Parietal - middle top
Temporal - middle bottom
Occipital - back
Cerebellum - base
What are gyri and sulci
Gyrus is peak
Sulcus is valley
What are the 12 cranial nerves?
Olfactory
Optic
Oculomotor
Trochlear
Trigeminal
Abducens
Facial
Vestibulocochlear
Glossopharyngeal
Vagus
Accessory
Hypoglossal
What are the layers of the meninges?
Dura mater
Arachnoid
Subarachnoid space
Pia mater
What is the difference between dorsal and ventral roots?
Dorsal is posterior and is responsible for sensory function
Ventral is anterior and responsible for motor function
Roots are part of the PNS
What are the types of neurone?
Unipolar
Psuedounipolar
Bipolar
Multipolar
How do axons package into nerves?
Contain both afferent and efferent neurones that split at the respective roots before entering the white and grey matter.
Packed in fasicles which are surrounded in perineurium
These are then packed in epineurium
Action potential
Opening of Na+ channels causes depolarisation
Repolarisation is by K+
Then goes to synapse and carries on by neaurotransmitters
What are glial cells?
Blood-brain barrier
- Done by astrocytes
- stops blood-borne items getting into brain
- form junctions around vessels
Chemical sensor
Microglia
-resident macrophages
Oligodendrocytes for myelination
Why cant CNS cells regenerate?
Because glial cells inhibit regen
Form scars
How do PNS cells regen
Activation of phagocytes which remove debris that might otherwise mess with growth
What is contralteral movement?
Fibre that moves to other side of body - if left foot pain, might be regualted by nerve that goes to right brain
What are the two pathways of sensory perception? What do they sense?
Dorsal-column medial leminiscus pathway
- for fine touch
Spinothalamic pathway
- for pain and temperature
Why is distinguishing between patients for types of perception important?
Because if they can feel touch on the opposite side of body, but not temperature, we know it is damage to the spinothalamic pathway
- if they can tell temperature but not touch too
What are the pathways of motor perception?
Lateral-corticospinal path
- neuron goes to other side at brainstem, is ipsilateral down the spinal cord to effector cell
Hence, if spinal cord damage occurs, you have damage to the same side
Vestibulospinal
- ear - balance
- entirely ipsilateral
Describe the dorsal-column medial leminiscus pathway
Dorsal-column medial leminiscus pathway
- contralateral movement occurs in the brain
- for fine touch
Sensory neurone runs to the dorsal part of the spinal cord, which then runs up the dorsal column of the . spinal cord into the brain, where it synapses with a secondary sensory neurone in the medulla to the thalamus, where it switches sides, terminating at the primary somatosensory complex
Describe the spinothalamic pathway
Spinothalamic pathway
- contralateral movement occurs in the spinal cord
- for pain and temperature
Sensory neurone recognises large temperature difference, carries impulse to spinal cord, where it switches sides, synapses and goes up the spinothalamic tract up to the thalamus where it synapses again and terminates in the primary somatosensory complex.
Describe the lateral corticospinal tract
Primary motor cortex sends impulse down medulla, where it switches side and goes down spinal cord via lateral corticospinal tract. Synapses with motor neurone and provides response.
