A thick bundle of nerve fibers ;connects the two hemispheres of the brain, ensures that both sides of the brain can locate and send signals to each other.
Mostly bilateral innervation from the cortex (upper face) and unilateral innervation (below the eyes). Because cranial nerves V, VII, IX, X, XI receive mostly bilateral innervation.
New cards
8
Corticospinal tracts
Leads to spinal nerves, mostly originates in the motor strip.
90% cross at medulla oblongata (pyramidal decussation) Lateral corticospinal tract- contralateral innervation _ L brain controls R hand. Skeletal muscle controls of more distal muscles like the hands (especially delicate skilled movements of hands (some forearms and toes)
10% (anterior corticospinal tract) cross below medulla – cervical level – control axial & girdle muscles of the trunk
New cards
9
Gray Matter
the darker tissue of the brain and __spinal__ cord, consisting mainly of nerve cell bodies and __branching dendrites__.
New cards
10
White Matter
the __paler__ tissue of the brain and spinal cord, consisting mainly of nerve fibers with their __myelin sheaths__.
New cards
11
Lower Motor Neuron
Responsible for transmitting the signal from the upper motor neuron to the effector muscle to perform a movement.
New cards
12
Motor Unit
\ A motor neuron and all of its associated muscle fibers are the basic functional units of skeletal muscle.
New cards
13
The process of neural transmission
A nerve impulse travels
Voltage-gated Ca+ channels open
Increased concentration of Ca+
Neurotransmitters diffuse across the synaptic cleft
Binding of neurotransmitters
Large Depolarization
New cards
14
Contralateral sensorimotor control
the arrangement whereby the motor cortex of each cerebral hemisphere is mainly responsible for control of movements of the contralateral (opposite) side of the body.
New cards
15
CNS anatomical symmetry
Both sides of the CNS anatomy is symmetrical.
New cards
16
Unilateral functional differences
The hemispheres have equal potential to develop language and other skills until age two
New cards
17
Cerebellum
Muscle synergy, coordination and smoothness in time and space, muscle tone, movement range, movement strength, equilibrium, compares efferent to afferent signals, important for motor learning and error control device.
New cards
18
Thalamus
Superior to brainstem. Considered subcortical. Is formed as the brainstem branches upward. Paired and oval-shaped bodies. Channels all sensory information (except olfaction) to cerebral cortex. Integrates sensorimotor information; with basal ganglia and cerebellar input, signals are sent via the Thalamus to the motor and pre-motor areas. Regulates cortically mediated speech, language, and cognitive functions.
New cards
19
Midbrain
Above the pons. Superior cerebellar peduncle-connecting brain centers with the cerebellum. Motor fibers leave cerebellum after analysis (go to thalamus and motor cortex.) Contains nuclei for many cranial nerves, contains ascending and descending fibers, contains 4 colliculi -2 superior and 2 inferior, these mediate auditory and visual information including reflexes- so the system is not overloaded with too much stimuli.
New cards
20
Medulla
\-The first location where the spinal cord meets the brain. Lowest part of the brainstem.
\-Contains ascending and descending pathways, contains cell bodies of many cranial nerves.
\- Inferior cerebellar peduncles connect medulla to the cerebellum. Mostly sensorimotor signals from body are sent to cerebellum here. Pyramidal tract (direct activation pathway) passes through the medulla. Major pathway connecting brain and muscle. Include corticobulbar tracts (leading to cranial nerves) and corticospinal tracts (leading to spinal nerves) Major landmark of the medulla are the pyramids (pyramidal decussation.)
New cards
21
Basal ganglia
Plays a large role in automatic movement and motor learning. Modulates cortical movement commands; regulates muscle tone, adjusts associated movements (arm swing, facial expression), suppresses extraneous movements, facilitates wanted/voluntary movements, and deals with mood and personality. Motor relay and integrating system, most motor pathways run through here.
New cards
22
Hypothalamus
Lies just below the thalamus. Regulates sensations and emotional behavior (temperature, sexual behavior, sleep-wake cycles, emotional expression.) It has connection to higher level CNS function as well as to the ANS.
New cards
23
Pons
Above the medulla; looks like a bulge in the brainstem. Middle cerebellar peduncles- connect pons with cerebellum. Signals from motor cortex sent to cerebellum here. Contains nuclei for many cranial nerves, contains ascending and descending fibers, contains descending corticospinal fibers (pyramidal tract).
New cards
24
Pyramidal decussation
The crossover of the corticospinal tract at the level of the medulla.
New cards
25
Wernicke’s area
language comprehension and auditory processing
New cards
26
Broca’s area
language production
New cards
27
Primary motor cortex
pre-central gyrus- main motor area
New cards
28
Primary sensory cortex
post-central gyrus- main sensory area,
New cards
29
Primary auditory cortex
On heschl’s gyrus- medial surface of superior temporal gyrus
New cards
30
Primary visual cortex
Most posterior occipital gyrus- main visual processing area
New cards
31
What are the functions of the Frontal Lobe
Motor planning and cognition
New cards
32
What are the functions of the Parietal Lobe
Dealing with processing sensory information
New cards
33
What are the functions of the Temporal Lobe
Auditory language formulation, and cognition.
New cards
34
What are the functions of the Occipital Lobe
Visual processing
New cards
35
Afferent vs Efferent
Afferent is when a neuron that transmits information to the CNS from the periphery; sensory. Whereas Efferent is when a neuron that transmits information away from CNS toward the periphery; motor.
New cards
36
A cortical lesion to the motor cortex results in
Generally minor effects to jaw movement, velopharyngeal, laryngeal, and breathing functions for speech.
New cards
37
Ascending (Sensory) Spinal Cord Tracts
\-Pain and temperature
\-General Diffuse Touch
Touch, proprioception, kinesthesia
New cards
38
Pain and temperature
(cross at level input to spinal cord) Damage to one side of the spinal cord will lead to loss of pain and temperature sensation below the injured spot, contralateral
New cards
39
General Diffuse Touch
(cross at level input to spinal cord) Travels to brain via lateral fasciculus (anterior spinothalamic tract- near pain pathway). Damage to one side of the spinal cord will lead to loss of diffuse touch sensation below the injured spot contralateral to injury side.
New cards
40
Touch, proprioception, kinesthesia
(crosses in the brainstem) Includes pressure, vibration , and muscle and tendon stretch sensations, knowledge of spatial position of body parts, and awareness of limb movement
New cards
41
Dendrites
Multiple extensions or processes from the cell body. These extensions collect and transmit electrical impulses toward the cell body.
New cards
42
Cell Body
Surrounded by a membrane through which nutrients enter and wastes can be shed
New cards
43
Axon
an extension from the cell body that transmits impulses away from the cell bod
New cards
44
Myelin
Fatty coating on the axon- speeds neural transmission
New cards
45
Axon Terminals
The bulbous endings of the axons
New cards
46
What happens to the motor and sensory functions if half of the spinal cord is cut?
Loss of motor abilities (paralysis) below level of damage on the ipsilateral side. Loss of discriminative touch, proprioception, and kinesthesia below level of damage on the ipsilateral side. Loss of pain and temperature sensation below level of damage on the contralateral side. Loss of g general touch sensation below level of damage on the contralateral side.
New cards
47
What happens to the motor and sensory functions if the spinal cord is cut completely?
Loss of motor abilities on both sides below the level of damage. And Loss of all sensation on both sides below level of damage.
New cards
48
Gyrus
Ridge
New cards
49
Sulcus
Depression
New cards
50
Fissure
Deep depression
New cards
51
Longitudinal Fissure
Serperates the 2 hemispheres
New cards
52
Central Fissure
AKA Central Sulcus or Fissure of Rolando; serperates the frontal part of each hemisphere from the remainder.
New cards
53
Lateral Fissure
AKA Lateral sulcus or Sylvian Fissure; Separates the temporal lobe from the rest of the hemisphere (like the thumb on the mitten.)
New cards
54
Parieto-occipital fissure
Imaginary line that separates occipital lobe from the rest- anatomical referent= occipital notch.
New cards
55
Function of Circle of Willis?
It serves as a safety valve, allows blood flow to continue to reach the brain even if there is a problem with blood flow from one of the major arteries supplying blood to the brain.
New cards
56
Temporal Gyri
Wernicke’s area is the posterior superior temporal gyrus- associated with language understanding and comprehension; auditory processing and memory.
New cards
57
Supramarginal Gyrus
Curves around end of lateral sulcus; important for writing- symbolic integration; body imaging, math & language, phonological processing.
New cards
58
Angular Gyrus
Curves around end of superior temporal gyrus- integration of visual lateral, reading & writing. Important for reading , word finding, L/R orientation, arithmetic , complex syntax and writing.
New cards
59
What are the three cerebral arteries and what areas of brain do they supply?
Anterior Cerebral Artery (ACA): superior and medial cortex surface, frontal pole.
Middle Cerebral Artery (MCA): Lateral surface of the brain; most commonly affected by CVA
Posterior Cerebral Artery (PCA): Posterior brain, occipital pole.
New cards
60
Thrombus
A blood clot on wall of artery
New cards
61
Transient Ischemic Attack (TIA)
A “little stroke” due to a temporary disruption of blood circulation to the brain where symptoms dissipate within minutes/hours. Sometimes precedes a thrombotic stroke. Last
New cards
62
Embolus
A blood clot that breaks free from a thrombus and enters the blood stream; travels within arteries until it gets a constriction of a turn where it lodges, disrupting blood flow. MCA is most common site for embolic strokes, typically happens suddenly with little to no warning.
New cards
63
Arteriovenous Malformation
Congenital tangled mass of arteries and veins in the brain. Grows like a tumor. Can sometimes hemorrhage. Can cause increased intracranial pressure- diffuse effects.
New cards
64
What is the striatum?
Refers to caudate and putamen
New cards
65
What is a dermatome?
An *area of skin in which sensory nerves derive from a single spinal nerve root.*
New cards
66
What do the 4 colliculi (superior and inferior) in the midbrain do?
They mediate auditory and visual information including reflexes - so the system is not overloaded with too much stimulus.
New cards
67
What does the indirect Activation Pathway do?
helps to prevent unwanted muscle contractions from competing with voluntary movements.
New cards
68
Organization of the spinal cord (ventral vs dorsal horn)
Lowest level of the CNS. Extends from base of skull to lower back, 1cm in diameter, protected by the vertebrae, gray matter inside, white matter outside. Posterior (dorsal) horns and anterior (ventral) horns.
Studied by 32 people
