Nervous System Physiology Part 10 Flashcards
In Parkinson Disease;
• Input to the basal nuclei is diminished.
• Interplay of excitatory and inhibitory circuits is unbalanced.
• Activation of the motor cortex (via basal nuclei–thalamus circuit) is reduced.
Parkinson disease is characterized by;
• Akinesia (reduced movement)
• Bradykinesia (slow movement)
• Rigidity
• Resting tremor
Parkinson Disease symptoms
• Parkinsonian gait
• Mask-like face
• Slowed movement
• Reduced arm swing
• Rigidity
• Asymmetric resting tremor
• Freezing
• Postural instability
• Shuffling steps
What are the Cerebellum Subdivisions?
• Vestibulocerebellum – Balance and eye movements
• Spinocerebellum – Body and limb movement coordination
• Corticocerebellum – Planning and timing of movements
Function of Vestibulocerebellum
Controls equilibrium
In people with Vestibulocerebellum dysfunction:
Equilibrium is far more disturbed during performance of rapid motions than during stasis, especially when these movements involve changes in direction of movement and stimulate the semicircular ducts.
Spinocerebellum: Info Types when a movement is formed
- Info from cerebral motor cortex & midbrain red nucleus → Intended sequential plan of movement the next few fractions of a second.
Feedback info from peripheral parts of the body (especially distal proprioceptors of the limbs) → what Actual movements result
Functions of Spinocerebellum
• Compares intended movement with actual performance
• Detects discrepancies between them
• Sends error signals to motor cortex & subcortical centers
• Allows for real-time correction of movements
What does the planning of sequential movements require?
That the corticocerebellum communicates with both the premotor and sensory portions of the cerebral cortex, and it requires two–way communication between these cerebral cortex areas with corresponding areas of the basal ganglia.
Function of Corticocerebellum
Corticocerebellum plays important roles in planning and
“timing” of sequential movements, which makes sure the individual can progress smoothly from one movement to the next in orderly succession.
What is ANS?
Autonomic nervous system (ANS) is the system of motor neurons that innervates smooth and cardiac muscle and glands.
What is the function of the ANS?
At every moment, signals stream from visceral organs into the CNS, and autonomic nerves make adjustments as necessary to ensure optimal support for body activities.
What is the ANS made up of?
Two neurons in series that connect the CNS and the effector cells.
Where is the cell body of the first Neuron in the ANS found?
• The first neuron has its cell body in the CNS.
Where is the synapse between the two neurons that make up the ANS?
The synapse between the two neurons is outside the CNS in a cell cluster called an autonomic ganglion.
What are the names of the neurons passing between the CNS and the ganglia?
preganglionic neurons
What are the names of neurons passing between the ganglia and the effector cells ?
postganglionic neurons.
Do the neurons of the sympathetic and parasympathetic divisions leave the CNS at the same levels?
different levels
Sympathetic divisions leave the CNS from the…..
thoracic (chest) and lumbar
regions of the spinal cord.
The parasympathetic division leaves the CNS from the….
the brainstem and the sacral portion of the spinal cord.
Where does most of the sympathetic ganglia lie?
close to the spinal cord and form the two chains of ganglia known as the sympathetic trunks.
What are the few other sympathetic ganglia called?
collateral ganglia
What are the few ganglia that make up the collateral ganglia?
celiac, superior mesenteric, and inferior mesenteric ganglia
Where does the collateral ganglia lie?
In the abdominal cavity, closer to the innervated organ.
Where do parasympathetic ganglia lie?
within, or very close to, the organs that the postganglionic neurons innervate.
What is the neurotransmitter released between pre and postganglionic neurons in automatic ganglia in both Sympathetic and parasympathetic divisions?
Acetylcholine
postganglionic cells have predominantly nicotinic acetylcholine receptors
In Sympathetic division what is the usual transmitter between postganglionic neuron and effector?
• In the sympathetic division, norepinephrine is usually the transmitter between the postganglionic neuron and the effector
In Parasympathetic division what is the neurotransmitter between postganglionic neuron snd effector?
• In the sympathetic division, norepinephrine is usually the transmitter between the postganglionic neuron and the effector
Do postganglionic neurons in the sympathetic division develop axons?
Never develops axons . Instead, these neurons form an endocrine gland, the adrenal medulla.
What happens upon activation by preganglionic sympathetic axons?
cells of the adrenal medulla release a mixture of about 80% epinephrine and 20% norepinephrine into the blood.
What are the parasympathetic and sympathetic effects on the eye (iris)?
Parasympathetic: Constricts pupils; Sympathetic: Dilates pupils.
What are the autonomic effects on the salivary glands?
Parasympathetic: Stimulate secretion of Watery saliva; Sympathetic: Stimulates secretion of Thick, viscous saliva.
What is the autonomic effect on sweat glands?
Parasympathetic: No effect; Sympathetic: Stimulates sweating.(Cholinergic fibers)
What is the autonomic effect of the adrenal medulla?
Parasympathetic: no effect. Sympathetic: stimulates muscle cells to secrete epinephrine and norepinephrine.
What are the autonomic effects on the heart?
Parasympathetic: Decreases rate; slows heart
Sympathetic: Increases rate and force of heartbeat.
What is the autonomic effect on the lungs?
Parasympathetic:Constricts bronchioles
Sympathetic:Dilates bronchioles
What is the effect of the autonomic nervous system on the digestive tract organs?
Parasympathetic:Increases motility (peristalsis) and amount of secretion by digestive organs; relaxes sphincters to allow foodstuffs to move through tract
Sympathetic:Decreases activity of glands and muscles of digestive system; constricts sphincters
What is the autonomic effect on the liver?
Parasympathetic:
Increases glucose uptake from blood
Sympathetic:Stimulates release of glucose to blood
What is the autonomic effect on blood vessels?
Parasympathetic:Little or no effect
Sympathetic:Constricts most vessels and increases blood pressure; constricts vessels of abdominal viscera and skin to divert blood to muscles, brain, and heart when necessary; epinephrine weakly dilates vessels of skeletal muscles during exercise
