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Flashcards in Module 3 Deck (341)
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151

o involves the anterior cerebellar lobe
o ataxia of the lower limbs only

Anterior (Rostral) Vermis Syndrome

152

o involves the flocculonodular and posterior lobes
o axial ataxia without extremity ataxia

Posterior (Caudal) Vermis Syndrome

153

o cerebellar signs lateralized to one half of the body

Cerebellar Hemisphere Syndrome

154

o bilateral cerebellar signs due to involvement of all cerebellar lobes

Pancerebellar Syndrome

155

- deep cerebral nuclei involved in motor control
- modulates thalamic outflow to the motor cortex to plan and execute smooth movements
- demonstrates programming functions
o generate basic patterns of movement in response to cues from cortical association areas

Basal Ganglia

156

Role of Dopamine

- connections between striatum and substantia nigra use dopamine as neurotransmitter
o inhibitory on the indirect pathway (D2 receptors)
o excitatory on the direct pathway (D1 receptors)
o overall action is excitatory

157

Important Functions of the Basal Ganglia

1. Cognitive Control of Motor Activity
2. Timing and Scaling Functions

158

o most of our motor actions occur as a consequence of thoughts generated in the mind
o major function of the caudate nucleus

Cognitive Control of Motor Activity

159

o basal ganglia control the speed and size of movement
o posterior parietal cortex is the locus for spatial coordination
o projects heavily to caudate nucleus and explains why timing and scaling functions are lost with basal ganglia lesions

Timing and Scaling Functions

160

- snake-like or writhing movements of the hand and arm or face
- result from lesions of the globus pallidus

Athetosis

161

- flailing movements of the extremities
- result from lesions to the sub thalamic nucleus

Hemiballismus

162

- brief, irregular, non-purposeful movements that are vaguely comparable to dancing
- result from lesions to the corpus striatum (specially on caudate nucleus)

Chorea

163

- results from widespread destruction of the dopaminergic cells in the substantia nigra
- characterized by:
o cogwheel rigidity
o resting pill-rolling tremor
o slowness or difficulty in initiating movement (bradykinesia, akinesia)
o postural instability (shuffling or fenestating gait)

Parkinson's Disease

164

- autosomal dominant genetic disorder caused by CAG trinucleotide repeats
o displays anticipation with succeeding generations

- characterized by flicking movements in individual muscles (chorea)
o leads to progressive severe distortional movements

- caused by depletion of GABA and acetylcholine from many areas of the brain

Huntington’s Disease

165

General vs. Special senses

General senses
Somatic (Cutaneous) senses
- Touch, pressure, vibration, warmth, cold, pain, tickle, itch and proprioception
Visceral senses
- Stretch, pain, chemo-, osmotic-, baro-

Special senses
Olfaction, vision, taste, hearing and equilibrium

166

- comes from “Soma” or “Somato” - Greek word which means “body”
- transmits information to the CNS about the state of the body and its contact with the environment

Somatosensory System

167

Somatosensory system

Sensory receptor cells

Neural pathways

Brain cortex

168

- receive stimuli from the external or internal environment
- Specialized epithelial cells
- Neurons that transduce environmental signals (light, temperature) into neural signals

Sensory receptor cells

169

- conduct information from the receptors to the brain or spinal cord

Neural pathways

170

deal primarily with processing the information

Brain cortex

171

- information processed by a sensory system may or may not lead to conscious awareness of the stimulus

Sensory information

172

- state of (conscious or unconscious) awareness of external and internal conditions in the body

Sensation

173

- conscious recognition of sensation
- damaged neural networks may give faulty perceptions
- Phantom limb: sensation of a limb that has been amputated

Perception

174

- onion-like structures surrounding unmyelinated nerve endings
- found in deep skin layers
- for vibration; tapping

Pacinian Corpuscle

175

- present in nonhairy skin; encapsulated in connective tissue
- found in superficial skin layers
- superficial touch (flutter and stroking movements)

Meissner's corpuscle

176

- encapsulated enlarged nerve endings found in deep skin layers
- for skin stretch

Ruffini's Corpuscle

177

- found in superficial skin layers
- for steady pressure and texture

Merkel's Disk

178

- found in muscles, joints, tendons
- for position

Propioceptors

179

Thermoreceptors

Warm receptors - free nerve endings in skin for warm temperature (30-45C)

Cold receptors - free nerve endings found in skin for cold temperature (20-35C)

180

- free nerve endings found in skin, muscle and viscera for noxious stimuli and extreme temperatures
- receptors for pain

Nociceptors