Neuromuscular Phys Flashcards
With spinal cord injury, what is the constellation of effects consisting spinal shock and how long does this last for?
ALL spinal reflexes depressed
- sweat
- vascular tone
- motor to gut/urinary
Lasts for at least 2 weeks
First reflex to regrow is usually contraction of the leg flexors and adductors in response to a noxious stimulus or knee jerk
Cessation of tonic excitatory impulses and removal of inhibition of inhibitory pathways: the effect is inhibition of motor neurons
p 234 Chapter 12 Ganong
What is the mass reflex?
Noxious stimuli post-spinal cord transection causing massive discharge
- massive flexor spasm
- bowel/bladder evacuation
- hypertension
- profuse sweating
Which pathway runs in the anterolateral column of the spinal cord? What happens when it is damaged?
Spinothalamic tract: pain pathway
- fibres cross in spinal cord
- ascend in anterolateral column
- terminate in lamina of dorsal horns
CORDOTOMY
- contralateral analgesia
- contralateral thermal anaesthesia
- all else intact
What are symptoms of damage to cerebellum? (9)
Hypotonia Ataxia Dysmetria Intention tremor Rebound phenomenon: can't stop movement promptly Dysdiadochokinesia Decomposition of movement: difficulty performing simultaneous movements at more than one joint Nystagmus Scanning speech: slurred speech
What is ballism? What pathology causes it?
Involuntary flailing intense and violent movements
Caused by disease of the BASAL GANGLIA
What are the largest areas represented in the somatic cortex? What are the smallest?
Largest: lips, face and thumb
Smallest: Trunk, lower body
What GLUT transporter is relevant for neuronal glucose uptake? Is neuronal glucose uptake insulin dependent?
2 minute supply of glycogen in neurons
GLUT 3 responsible for uptake
Not insulin dependent: even T1DM has excellent glucose uptake
What is contained between z bands?
Overlapping of actin and myosin. Moves closer together in contraction.
Is the ends of the sarcomere
Which is the thick vs thin filament? Actin or Myosin?
Thin filament: actin
Myosin: thick filament
What are the subunits of troponin and what do they do?
Troponin C binds to calcium, activating to bind tropomyosin.
Troponin T is the part that moves tropomyosin off myosin binding sites on actin to allow for movement.
What percentage of the metabolism of cardiac muscle is fat vs carbs?
fat 60%
carbs 35%
amino acids <5%
What is a renshaw cell?
Renshaw cells are inhibitory cells in the anterior horn that transmit inhibitory signals to the surrounding motor neurons
Stimulation of each motor neuron tends to inhibit adjacent motor neurons (lateral inhibition)
What’s the difference between microglia and macroglia? What are some examples?
Microglia: immune cells
- resemble macrophages and remove debris
- arise from macrophages outside of nervous system
Macroglia
- oligodendrocytes: CNS myelin
- schwann cells: peripheral myelin
- astrocytes: helps capillaries form tight junctions to make up blood-brain barrier
What is the weber test and how do we interpret the findings?
Tuning fork to vertex
Conduction deafness – louder in diseased ear because masking effect of environment noise is absent on diseased ear
Sensorineural – sound louder in normal ear
What is the Rinne test and how do we interpret the findings?
Tuning fork to mastoid process until no longer can hear, then move prongs to in front of ear
Conduction deafness – vibrations in air not heard after bone conduction is over
Sensorineural deafness – vibration heard in air after bone conduction is over, as long as nerve deafness is partial
What are the intracellular mechanisms when activating alpha 1 receptors alpha 2 receptors beta 1 receptors with noradrenaline
alpha 1: activates phospholipase c, increasing production of DAG, IP3 and inositol phosphates
alpha 2: inhibits adenylyl cyclase to decrease intracellular production of cAMP
beta1: activates adenylyl cyclase to increase intracellular production of cAMP
Where is the central nervous system control located for the vasodilatory system?
Anterior hypothalamus
What happens when repeated stimulus to a neurotransmitter occurs? (2 options)
Homologous desensitization: loss of responsiveness only to the particular ligand and maintained responsiveness of the cell to other ligands
Heterologous desensitization: the cell becomes unresponsive to other ligands as well.
What parts of the brain make up the basal ganglia?
What are characteristic symptoms of dysfunction in each?
- caudate nucleus
- putamen: chorea
- globus pallidus: athetosis
- substantia nigra: parkinson’s
- subthalamic nucleus: hemiballismus
Which SNS postganglionic neurons are noradrenergic? Which are cholinergic?
Cholinergic
- sweat glands
- neurons that end on blood vessels in skeletal muscle and produce VASODILATION
- the rest are noradrenergic
During accomodation, what happens to the ciliary muscles? What happens to the lens ligaments?
What happens to the lens itself?
- ciliary muscles contract
- relax the ligaments
- increase the curvature of the eye
- attempting to increase refraction
What is the triple response? How is it mediated?
When the skin is stroked more firmly with a pointed instrument, there is reddening at the site in about 10s (red reaction) This is followed in a few minutes by local swelling (wheal) and diffuse mottled reddening (flare) around the injury.
red reaction: capillary dilatation due to pressure
wheal: local oedema due to substance p
flare: arteriolar dilatation
What is nerve growth factor?
- released during tissue damage by astrocytes/muscles
- alters gene expression in cell body of neuron to release substance p to increase nociceptor sensitivity
- flags pain to tissue damage/potential tissue damage
