Mod 2 Flashcards
Function and structure of the SNS
Release sweat
Contraction of arrector pilli
Dilation
Vasoconstriction
Accelerates heartbeat
Increase force of contraction
Reduce peristalsis in alimentary canal
Dilate pupils
Contract smooth muscles to open eyelids
Increase peristalsis carrying spermatozoa
Relax smooth muscle for easier breathing
Release epinephrine
Function and structure of the PSNS
Constrict pupils
Contract to relax suspensory ligaments
Tear and serous secretion flow
Decrease heartbeat
Bronchioconstriction
Respiratory, pancreas, and alimentary canal gland secretion
Alimentary canal peristalsis
Relax sphinceter muscles
Facilitates bile release
Stimulates erection
Neurotransmitters of the ANS
PSNS is primarily cholinergic.
- responds to acetylcholine
- nicotinic: PSNS and SNS
- muscarinic: PSNS
SNS is primarily adrenergic.
- respond to epinerphrine
Motor areas
Premotor cortex: postural and axial movements
Supplementary motor cortex: trunk and girdles, bilateral coordination
Fontal eye fields: coordinate eye movements
Cingulate motor areas: emotional aspects of movement
Motor areas of the cerebral cortex
The grey matter of the cerebral cortex has 6 layers of cells, each with a specific function.
- Layer V is most prominent with pyramidal cells of the UMN
Cell columns serve one specific area of the body
Path of the corticospinal tract
Axons descend:
1. corona radiata
2. internal capsule
3. midbrain
4. pons
5. most fibers decussate in the lower medulla
6. spinal cord
Will synapse on one of three cells:
1. interneurons
2. alpha motor neurons
3. gamma motor neurons
Lateral and anterior corticospinal tracts
Lateral:
- distal musculature
- damage –> UMN symptoms
Anterior:
- axial, girdle musculature
Corticonuclear tract
Terminate in head and neck
Synapses on:
- cranial nerve nuclei
- brachiomotor nuclei (skeletal mm of head and neck)
Muscle spindles
Extrafusal muscle fibers make up the bulk of the muscle and cause muscular contraction leading to movement.
- innervated by alpha motor neurons
Intrafusal muscle fibers make up the muscle spindles and provide feedback regarding muscular contraction
- innervated by gamma motor neurons and sensory fibers
UMN symptoms
Spastic
Hypertonic
Hyperreflexic
Disuse atrophy
Positive babinsky
LMN symptoms
Flaccid
Hypotonic
Hyporeflexic
Denervation atrophy
Negative babinsky
Descending motor pathways
Corticotectal and tectospinal tracts
Corticorubral, rubrobulbar, and rubrospinal tracts
Corticoreticular and reticulospinal tracts
Vestibulospinal tracts
Corticotectal and tectospinal tracts
Coordinate head and eye movements
Tectum: where the superior colliculus resides
Corticorubral, rubrobulbar, and rubrospinal tracts
Coordinate hand and digits
Red nucleus: facilitates alpha and gamma neurons
Corticoreticular and reticulospinal tracts
Coordinates posture and limb movements
Reticular system: functions in consciousness