Basics Of Neuoanatomy And Neurophysiology Flashcards
T/f: nervous and muscular tissue membranes are excitable
True
T/f: membranes are irritable and sensitive to electrochemical change
True
T/f: excitability can be communicated bw the tissues of the body
True
How are nerve and muscle cells able to produce movt?
By transmitting electrochemical info
What are excitatory action potentials?
Input that depolarizes a neuron, making it more likely to reach an action potential
What are inhibitory action potentials?
Input that increases negative resting potential, hyperpolarization, making it less likely to reach an action potential
What is the threshold for action potentials?
The voltage level that must be reached before rapid depolarization relate to axon size
Do larger or smaller axons have a lower threshold for action potentials?
Larger axons have the lowest threshold that are more easily stimulated
Some TM can stimulate _____ production for effecting the cellular process of muscle contraction
ATP
Order these muscle fibers from largest to smallest: Beta, alpha, C, delta, gamma
Alpha, beta, gamma, delta, C
What nerve fibers carry sensory info?
A beta 1a and 1b
What nerve fibers carry motor info?
A alpha and A gamma
What nerve fibers carry pain and temp?
A delta and C fibers
What NT is stored at the presynaptic ending of the myoneural junction?
Ach
What does Ach do in the muscle fibers?
Its release is stimulated by the arrival of a nerve impulse and interacts with receptors in the muscle fiber membrane, increases its permeability of the membrane to ions and the cell depolarizes
What are somatic receptors?
Body receptors that give the NS info about temp, touch, pain, tension, and position
What causes a muscle contraction?
Change in electrical potential in the immediate vicinity of actin and myosin filaments that triggers the process of sarcomere shortening
What are energy transducers on somatic receptors?
End organs of receptors that convert mechanical or thermal energy into electrical energy
What is a generator potential?
The conversion of mechanical or thermal energy into electrical energy
A stimulus sufficient in ____, _____, or _____ will cause an action potential to be generated and transmitted by afferent nerve to the CNS
number, timing, intensity
What are cutaneous (skin) receptors?
Receptors on the skin that responds to touch, pressure, or stretch of the skin
What are free nerve endings?
Receptors that are innervated by A delta and c fibers that respond to noxious stim and temp changes (pain receptors)
What is the receptor field?
The area of skin in which it is possible to activate a sensory nerve fiber
What are proprioceptors?
Joint, tendon, and muscle receptors that detect changes in tension and position of structures, muscle length, and rate of change of muscle length
What are the two types of proprioceptors?
GTOs and muscle spindles
What are joint receptors?
Receptors found in the joint capsules and ligaments that emit several action potentials per second at rest and provides position sense
How are joint receptors stimulated?
By deforming forces during movt providing the CNS with info on the joint position and rate of joint movement
Where does the SC run through?
From the BS to L2
What does the SC do?
Communication and coordination of motor info and movt patterns
Where is gray matter located?
In the central area, motor neuron cell bodies, and synapses in a butterfly shape
The unmyelinated portion
What is white matter?
Axons to and from the CNS
Cell bodies of sensory neurons that lie in the DRG outside the SC
What does the post/dorsal horn contain?
Synapses of sensory afferents
What does the ant/ventral horn contain?
Cell bodies of LMNs
Efferents to the muscle
What are the two main sensory ascending tracts (afferent tracts)?
Posterior/dorsal white column
Anterior spinothalamic tract
Where do the posterior/dorsal white column fibers run?
They enter the SC in the dorsal horn, ascend the SC and cross to the other side of the brain in the medulla to carry sensation from one side of the body to the other side of the brain to get processed
What info does the posterior/dorsal white column carry?
Proprioception
Vibration
2 point discrimination
Deep touch
Where does the anterior spinothalamic tract run?
Enters the dorsal horn, synapses and crosses to the other side of the SC within 3 segments and the info is first relayed to the thalamus
What info does the anterior spinothalamic tract carry?
Pain and temp
What are the descending motor tracts (efferent tracts)?
Corticospinal (paramidal) tract
Rubrospinal tract
Reticulospinal tract
Tectospinal tract
Vestibulospinal tract
What is the main motor descending tract?
Corticospinal (paramidal) tract
Where does the Corticospinal tract run?
Originates in the frontal lobe, crosses to the opposite side in the BS, continues through the interconnections and synapses onto an anterior horn cell in the SC
What is the anterior horn cell?
Alpha motor neuron
A large neuron located in gray matter of the SC that sends axons out of the ventral root and gives rise to peripheral nerves
What is a motor unit?
An alpha motor neuron and all the muscle fibers it innervates
What info does the Corticospinal (paramidal) tract carry?
Motor info
Where does the rubrospinal tract run?
The red nucleus of the midbrain to LMNs going to the UEs
What does the rubrospinal tract do?
Facilitates flexors, inhibits extensors
Where does the reticulospinal tract run?
Reticular formation throughout the BS
What does the reticulospinal tract do?
Facilitates limb extensors, another part facilitates flexors and inhibits extensors
What does the tectospinal tract do?
Provides orientation of the head toward sound or moving object
What does the vestibulospinal tract do?
Assists in postural adjustments to keep the head balanced on the trunk
What efferent tract has a close anatomical relationship to the mechanisms of the inner ear?
The vestibulospinal tract
What are the structures of the BS?
Midbrain
Pons
Medulla
What is the midbrain?
The relay area for tracts passing through the cerebrum, cerebellum, and SC
Reflex center for visual, auditory, and tactile responses
What structure of the BS contains axons that travel bw the cerebellum and the rest of the CNS?
The pons
What is the medulla?
An extension of the SC that contains sensory and motor nuclei for the neck, mouth, and control centers for respiration and HR
Reflex centers for vomiting, sneezing, and swallowing
What are the structures of the diencephalon?
Thalamus and hypothalamus
What structure of the diencephalon is the central relay station for all sensory information coming from the body to the cerebrum?
The thalamus
What is the thalamus?
The relay area for motor info from the cerebellum and basal ganglia
Projections from the thalamus and sensory cortical areas to the temporal lobes are responsible for what?
Pain memory
T/f: the projections of the hypothalamus trigger an autonomic response to pain
True
What structure of the diencephalon regulates homeostasis?
The hypothalamus
What functions of homeostasis does the hypothalamus regulate?
Body temp, BP, hunger, sleep-awake cycles
What are the nuclei of the BG?
Caudate, putamen, globus pallidus, substantia nigra, and sub thalamus nuclei
The BG plays a vital role in what functions?
Regulation of posture and muscle tone
Does the BG have direct input from the SC?
Nope, but it does have direct input from the cortex
T/f: the BG plays an important role in control of autonomic and voluntary movt, exerting effects in motor planning areas of the motor cortex
True
What structure of the brain is the coordinator of motor activities?
The cerebellum
What is the cerebellum responsible for?
Programming rapid movt, correcting the course of rapid movt, and correlating posture and movement
What brain structure regulates balance and coordination?
The cerebellum
T/f: the cerebellum regulates and adjusts the accuracy, intensity, and timing required by specific movt tasks
True
What brain structure constantly monitor and compares movt requested to the actual movt?
The cerebellum
Where is the motor cortex located?
In the frontal lobe
What is the frontal lobe responsible for?
Voluntary control of complex motor activities, cognitive fxn, judgement, attention, mood, abstract thinking, aggressions
What is the primary motor cortex responsible for?
Contralateral voluntary control of the UE and facial movts
What is the premotor cortex responsible for?
Controlling muscles of the trunk and muscles used in anticipatory postural adjustments
What is the supplementary motor cortex responsible for?
Controlling the initiation of movt, orientation of head and eyes, and bilateral movt
Where is the primary sensory cortex?
In the parietal lobe
Where is the primary sensory cortex?
In the parietal lobe
Where is incoming sensory info processed and given meaning?
In the primary sensory cortex of the parietal lobe
Where is the somatosensory cortex located?
In the parietal lobe
What is the somatosensory cortex?
The major processing center for all somatosensory modalities
Where is the primary auditory cortex located?
In the temporal lobe
What does the primary auditory cortex in the temporal lobe do?
Auditory discrimination for speech comprehension
Where is the primary visual cortex located?
In the occipital lobe
What is the primary visual cortex in the occipital lobe responsible for?
Processing and interpretation of visual info, judging distances, and seeing in 3D
Visual info from the R half of the visual world is received by what hemisphere?
The L hemisphere
Visual info from the L half of the visual world is received by what hemisphere?
The R hemisphere
