Fundamental physiology basics if the neurologic exam Part 1 & 2 Flashcards
An excitable cell that receives a stimulus from a neuron or a receptor (dendrites)
Integrates it (ranks it, compares it to other stimuli) (cell body, axon hillock)
Passes along another stimulus if it is adequately stimulated (axon)
Neurons
Axons are carried in bundles (True/False)
True
-nerves in the peripheral system
-tracts in the central nervous system
Which neuronal cell bodies don’t reside in the CNS?
Dorsal root ganglia, autonomic ganglia, enteric ganglia
Neuronal cell bodies for the axons that bring most sensory information from the PNS to the CNS
Dorsal root ganglia
help regulate the activities of the autonomic nervous system
Autonomic ganglia
Help regulate the activity of the gut
Enteric ganglia
What sections make up the cerebrum?
cortex, basal ganglia, limbic structures
What area of the brain is responsible for most of our “higher functions”
-formation, storage, retrieval of memory (together with the limbic structures)
-speech & language
-abstract thinking, math, planning, and executing plans
Cerebral cortex
Also responsible for “what we’re conscious of”
-perception
-voluntary movements, both simple and complex
Name the lobe based on these functions:
-simple movements; pre-central gyrus
-complex motor plans; anterior portions + pre-central gyrus
-motor aspects of speech; anterior and inferior to the precentral gyrus
-planning, abstract thinking, social behavior (executive functions); distributed throughout this lobe & parietal lobe
Frontal lobe
Name the lobe based on these functions:
-Perception of touch, temperature, vibration; postcentral gyrus
-perception of “where our limbs are” (proprioception); post-central gyrus
-memory, executive functions, abstract reasoning; distributed throughout this lobe
Parietal lobe
Name the lobe based on these functions:
-hearing
-scent, taste
-recognition of speech
-memory (in cooperation with the limbic structures below it)
Temporal lobe
Name the lobe based on these functions:
-Vision
-Areas that relate visual stimuli to “actual things” (association cortex)
-memories related to what has been seen
Occipital Lobe
Memory formation requires what?
Attention and structures that “process” and form new memories.
Attention is associated with what?
prefrontal lobe
the structures of the limbic lobe below the temporal lobe
Memory “processors”
-hippocampus, amygdala
memory storage->
Memories tend to be stored in the cortex “close to” the sensation they’re associated with
ex) memory of a voice or word is likely in or close to the temporal lobe
Structures that lie below the cortex, close to the middle of the parietal and temporal lobes
serve to refine and regulate behaviors or movements
impaired in several diseases-when they lose function: tremors, rigidity, difficulty initiating movements, random/purposeless movements, tics, vocal utterances, personality changes
The basal ganglia
What are the deep structures in the cerebrum?
Basal ganglia: striatum, globus pallidus, subthalamic nuclei
Limbic structures: Amygdala & hippocampus
Relays information from sensory receptors in the peripheral nervous system to the cortex
-Joint/limb position and movement
-pain, touch, temperature
Relays information from brain areas to refine motor planning
-cerebellum, basal ganglia
Thalamus major roles
Controls much of the endocrine system, along with the pituitary gland
Regulates temperature, activity of the autonomic nervous system, fluid balance
Some thalamic nuclei modulate emotion and memory formation
Hypothalamus major roles
Name the structures:
1) Hypothalamus
2) Pituitary gland
3) Thalamus
-About 10% of the mass of the brain
-General function: compares information from the receptors that sense; joint position and movement, gravity, and equilibrium
-uses this information to adjust movements that are formulated in the prefrontal cortex (it very quickly error-corrects movements that are planned by comparing them to data from the receptors described above
Cerebellum
-Composed of the midbrain, pons, and medulla
-Cranial nerves found throughout this area
-All of the pathways that bring sensory information into the brain (from the PNS) or send motor information out of the brain (to the PNS) pass through here.
Brainstem
-Isolated from the peripheral nervous system and the rest of the body by a set of membranes (meninges)
-bathed in unique extracellular fluid (cerebrospinal fluid)
-neurons or axons do not usually regenerate after they have been damaged (regeneration is common after damage to axons in the PNS)
-Different (simpler) structure than the brain
Dorsal components tend to carry sensory information to the brain
Ventral components tend to carry motor information away from the brain to effectors (muscles in particular)
Spinal cord-Central Nervous System
-mostly cell bodies mixed with unmyelinated or lightly-myelinated axons
-Divided into two horns (ventral and dorsal)
Gray matter (yellow in this picture)
Cell bodies of neurons that control skeletal muscles.
Ventral Horns
Cell bodies of neurons that relay and integrate sensory information to the brain.
Dorsal Horns
Divided into columns- these are myelinated axons, no cell bodies. (dorsal, lateral and ventral columns)
White matter
Proprioception(joint/limb position), vibration sense, fast pain fibres - sensory to brain
Dorsal Columns
Pain, temperature, itch-sensory to pain
Anterior & Lateral columns
motor information to skeletal muscles
Anterior columns
Motor plan formed (pre-frontal cortex) ->
Activation of neurons in the primary motor cortex (prefrontal lobe) ->
Axons travel through the brainstem (medullary pyramids) and cross over to the opposite side->
Activation of primary motor neurons in the ventral horn that stimulates skeletal muscle contraction
or
Activation of motor neurons in the ventral horn that modify reflexes
Corticospinal tract
(lateral and anterior)
Lateral corticospinal tract
fine movements of extremities
Anterior corticospinal tract
movements of the trunk
It is estimated that up to ____% of corticospinal output is to “shut down” reflexes that would oppose voluntary movements.
90%
Cerebellum integrates information from proprioceptors ___________________ and the inner ear ____________________
-Compares this information with information from the motor “plan” generated by the _____________________
Cerebellum “adjusts” the motor plan by communicating (via the thalamus) with the ___________ and refining the movements relayed by the _________________________
-Spinocerebellar tract
-vestibulocerebellar tract
(keeps the cerebellum “up to date” on the actual position of the body in general and specific joints)
-Frontal lobe
(relayed through the pons)
-Frontal lobe
-corticospinal tract
The motor system depends heavily on input from receptors about the position of a joint, tension across a joint, and tension in a skeletal muscle.
Together, these are known as _________________
proprioceptors
Inform the cortex, the cerebellum, and neurons in the spinal cord about the actual position of the body.
Proprioceptors
proprioceptor-> dorsal horn-> dorsal column-> thalamus-> post-central gyrus of the parietal lobe
Dorsal column-medial lemniscal system