Lesson 5 Flashcards
Glial Cells
- provide support and nutrients to neurons
1. astrocytes
2. Microglia
3. Oligodendrocytes
4. Schwanns Cells
Astrocytes (glial cells)
- suspends and separates neurons
- connects to blood capillaries & assists in transporting substances from the blood to the nerve cells
microglia (glial cells)
- cleans damaged tissue from a lesion in the nervous system
- surrounds and destroys harmful organisms
schwanns cells (glial cells)
-form myelin in peripheral nervous system
Neuron (nerve cell)
-communication elements of the nervous system
What are the Neuron structures?
- Soma (cell body)
- Dendrite
- Axon
- Axon hillock
- myelin sheath
- Nodes of Ranvier
- Telodendria
- Terminal Buttons
- Synaptic Vesicles
- Neurotransmitters
- Synapse
Dendrite (neuron structure)
short projections that conduct impulses toward the cell body
Axon (neuron structure)
longer projection that conduct impulses away from the cell body
axon hillock (neuron structure)
junction between axon and soma
myelin sheath (neuron structure)
- white fatty covering on axon
- protects and insulates the axon
- increases rate of neural conduction
Nodes of Ranvier (neuron structure)
- area between myelinated segments where the axon is exposed
- permit saltatory conduction
- > process in which info in the axon passes from node to node, thereby greatly increasing conduction in speech
Telodendria (neuron structure)
smaller branches extending from end of axon
Terminal buttons (neuron structure)
- located at tip of telodendria
- transmit information to next neuron
- contain synaptic vesicle
synaptic vesicles (neuron structure)
contain neurotransmitters
neurotransmitters (neuron structure)
chemical substance that transmits nerve impulses across a synapse
synapse (neuron structure)
small gap between connecting neurons
multiple sclerosis
- chronic disease
- myelin in the central nervous system is destroyed
- myelin forms scar tissue (sclerosis)
- nerve impulses are distorted or interrupted
- symptoms vary based on located and severity of myelin damage
Neurotransmission
communication between neurons by the movement of chemicals across a synapse
neurotransmitters are released…
into synaptic cleft to facilitate transmission of info from the presynaptic neuron to postsynaptic neuron
Neurotransmitters
- acetylcholine, serotonin, dopamine
- excitatory ->increase in activity
- inhibitory ->reduction in activity
Functional differences between neurons
- interneurons
- sensory neurons
- motor neurons
interneurons
communicating within the nervous system
sensory neurons (afferent)
communication sent from the body toward the central nervous system
motor neurons (efferent)
communication sent from the central nervous system to the body
Nerve pathways and tracts
- neurons function in groups
- wrapped together in bundles that form nerve pathways or tracts
- > efferent
- > afferent
- > mixed
upper motor neurons
- neurons located within the central nervous system
- responsible for carrying impulses for voluntary motor activity from the cerebrum to the lower motor neurons
lower motor neurons
- neurons located in the peripheral nervous system
- provides impulses/info directly to peripheral structures
Neuromuscular junction
the point of synapse between neuron and muscle
myasthenia gravis (disorder)
- chronic autoimmune neuromuscular disorder
- autoimmune responses destroys or blocks the receptor sites of the neuromuscular junction (neurotransmitters are unable to stimulate a response)
- fluctuating weakness of voluntary muscle groups
- hypernasal speech w/ reduced intelligibility
- difficulty chewing and swallowing
divisions of the nervous system
- anatomical division
- functional division
anatomical division of the nervous system
- central nervous system (CNS)
- peripheral nervous system (PNS)
Central nervous system (anatomical div)
- brain (cerebrum, subcortical structures, brainstem, & cerebellum)
- spinal cord
peripheral nervous system (anatomical div)
- cranial nerves
- spinal nerves
- sensory receptors
functional division of the nervous system
- autonomic nervous system
- somatic system
autonomic nervous system (functional div)
-involuntary functions ( heart rate, digestion, breathing)
- sympathetic system
- > expends energy
- parasympathetic system
- > conserves energy
Somatic system (functional div)
-voluntary motor control
-pyramidal system (direct)
->initiation of voluntary motor acts
-extrapyramidal system (indirect)
->controls background tone & movement to support
primary motor acts
cerebrum - basic structures
- cerebrum cortex
1. Gyri
2. Sulci
3. Fissure
Gyri (cerebrum)
convolutions
sulci (cerebrum)
infoldings
fissure (cerebrum)
deep pronounced infoldings
major landmarks of the central and peripheral nervous system
- central fissure/ sulcus
- lateral fissure/ sulcus
- cerebral longitudinal fissure
central fissure/sulcus (landmark)
- rolandic fissure
- separates the frontal lobe from parietal lobes
lateral fissure/sulcus (landmark)
- sylvian fissure
- separates temporal lobe from frontal an parietal lobes
cerebral longitudinal fissure
-separates left hemisphere from right hemisphere
LEFT hemisphere (cerebral longitudinal fissure)
- linear, analytical, logical
- math, science, language formulation
RIGHT hemisphere (cerebral longitudinal fissure)
- holistic, imaginative, creative
- music, art, language expression
lobes
frontal parietal temporal occipital insular
frontal lobe
- planning, initiation, & inhibition of voluntary motions & thought processes
1. Broca’s area
2. Precentral gyrus
3. premotor region
4. anterior portion of front lobe
Broca’s Area (frontal lobe)
- speech motor planning
- dominant (left) hemisphere
precentral gyrus (frontal lobe)
- motor strip
- initiation of voluntary motor movement to contralateral side of the body
- specific portions of the motor strop control specific muscles and structures
premotor region (frontal lobe)
motor planning
anterior portion of frontal lobe
- memory
- emotion
- thought processes (reasoning, problem-solving, judging)
parietal lobe
- postcentral gyrus
- inferior parietal lobule
- angular gyrus
- supramarginal gyrus
postcentral gyrus (parietal lobe)
receives sensory information
inferior parietal lobule (parietal lobe)
interprets visual, auditory and somatic sensory info
angular gyrus (parietal lobe)
- involved in mathematical calculation
- reading and writing
- impairment may cause dyslexia &/or dysgraphia
supramarginal gyrus (parietal lobe)
-phonological development (rhyming & reading development)
temporal lobe
- Heschl’s gyrus
2. Wernicke’s area
Heschl’s Gyrus (temporal lobe)
-receives auditory information from the ears
Wernicke’s area (temporal lobe)
- processes receptive language (comprehension and formulation of spoken language)
- dominant (left) hemisphere
aphasia (disorder)
- acquired language disorder involving difficulty producing or comprehending language (spoken & written)
- generally caused by brain damage due to stroke, trauma, or tumor near Wernicke’s area & Broca’s area
- Mild to severe
Occipital lobe
- calcarine sulcus
- > primary reception area for visual information
insular lobe
- insula
- deep to the lateral fissure
- it is believed to be involved with speech function, the limbic system, and visceral function
- gustation (taste)
Cortical Connections
- Projection Fiber
- Association Fibers
- Commissural Fibers
projection fibers (cortical connections)
-tracts communication to an from the cerebral cortex
brainstem and spinal cord
association fibers (cortical connections)
- communicating fibers between regions of the same hemisphere
- short association fibers
- long association fibers
Shorts association fibers (cortical connections)
-connect neurons of one gyrus to the next gyrus
long association fibers (cortical connections)
- connect the lobes of the brain in the same hemisphere
- arcuate fasciculus
arcuate fasciculus (long association fibers)
-connect Wernikes area to Broca’s area
Commissural Fibers (cortical connections)
- communicating fibers between the right and left hemisphere
- corpus callosum
Corpus Callosum (commissural fibers)
- agenesis of the corpus callosum:
- ->birth defect in which the corpus callosum is not fully formed or is only partially formed
subcortical areas of the brain
- Limbic system
- Basal Nuclei
- Thalamus
- Hypothalamus
Limbic system - FUNCTION
subcortical areas of the brain
involved in motivation, emotion, memory, reproduction, feeding behavior, and olfaction
limbic system- IMPORTANT STRUCTURES FOR COMMUNICATING
subcortical areas of the brain
- hippocampus
2. amygdala
Hippocampus
important structure for communicating
- learning & memory
- transfers memories from short term to long term memory
Amygdala
important structure for communicating
- involved in ascribing emotion to events and behaviors
- also aids in memory building
Basal Nuclei - STRUCTURES
subcortical areas of the brain
- Caudate nucleus
- Globus pallidus
- Putamen
- Substantia Nigra
- >contains dopamine neurotransmitters
Basal Nuclei - FUNCTIONS
subcortical areas of the brain
- regulates motor control for posture, balance & background muscle tone
- control of precise voluntary movements through inhibition (helps to refine & smooth movements)
Parkinson’s Disease
- neuromuscular disease
- degeneration of dopamine-containing neurons in the substantial nigra
Parkinson’s Disease - SYMPTOMS
- slowness of voluntary movements
- trembling of hand at rest
- decreased facial expression and monotone speech
- shuffling gait
- swallowing problems (dysphagia)
Thalamus - FUNCTION
subcortical areas of the brain
- relay station
- > all information traveling to the cerebral cortex (exception olfaction) passes through the thalamus
- > sorts & interprets info & decides which signal should be transmitted to the cerebrum
Hypothalamus- FUNCTION
subcortical areas of the brain
- involved in sensory & motor of visceral function
- regulates hormonal function, body temperature, hunger, sleep-wake cycles, blood pressure, and other function
cerebellum- FUNCTION
- regulate posture and coordination
- coordinates motor commands with sensory inputs to control movements
- > rate
- > range
- > force
Ataxia
- without coordination
- caused by infections, injuries, degenerative diseases that affect the cerebellum
- may cause coordination impairment in writing, walking speech and swallowing
Brainstem -FUNCTION
- responsible for basic body function to maintain life
- site of many reflexes involved in respiration, swallowing and digestion
- origin of cranial nerves
- pathway between cerebrum,cerebellum and spinal cord
brainstem -STRUCTURES
- midbrain
- pons
- medulla
midbrain
brainstem structure
- contains cerebral peduncles (large bundle of nerve pathways) that provide communication to and from the cerebrum
- > corticospinal tract
- > corticonuclear tract
corticospinal tract
midbrain
projects muscle control to extremities
corticonuclear tract
- corticobulbar
- project muscle control to cranial nerves
Amyotrophic Lateral Sclerosis (ALS)
- degenerative disease of the nervous system
- causes muscle atrophy in the muscles of the extremities, trunk, mouth, and face
- corticospinal involvement symptoms will show up in fine motor movements of the extremities first
- corticonuclear (bulbar) involvement will show up in speech and swallowing first
Pons
brainstem structure
- bridge to connect cerebellum and the rest of the nervous system
- contains olivary complex
- > aid in localization of sound and noise reduction
medulla
brainstem structure
Pyramids
-location where cerebral motor commands cross (decussate) from one side of the body to the contralateral side of the body
unilateral motor impairment
- muscle paresis (weakness) or paralysis (loss of muscle control on one side of the body)
- neurological damage is on the opposite side of the brain
Spinal Cord - STRUCTURES
- Central Canal
- White Matter
- Gray Matter
- Spinal Nerve
Central canal (spinal cord structures)
cerebral spinal fluid
white matter (spinal cord structures)
- contain sensory (ascending) and motor (descending) pathways
- > sensory (afferent) pathways
- > motor (efferent) pathways
sensory (afferent) pathways
white matter
-transmit information about pain, temperature, touch, and proprioception to the thalamus, cerebrum, and cerebellum
gray matter (spinal cord structures)
- site of neuron synapse
- > Dorsal (posterior) Horn (root)- Afferent (sensory) information
- > Ventral (anterior) Horn (root)- Efferent (motor) information
Spinal nerve (spinal cord structures)
- contain both sensory and motor branch
- sensory branch exits the spinal cord at the posterior root
- motor branch enters the spinal cord at the anterior root
- the two branches converge outside the spinal cord to form the spinal nerve
31 pairs of spinal nerves
8 Cervical 12 Thoracic 5 Lumbar 5 Sacral 1 Coccygeal
Spinal Reflex Arc
spinal nerve
- simple stimulus response
- sensory nerve ending receives a stimulus
- sensory information travels to the spinal cord via the posterior horn
- synapse with a connecting neuron within the gray matter
- synapse with a motor neuron in the anterior horn
- information travels along the motor neuron to the neuromuscular junction
- reflexive movement
protective and circulatory systems
- Meningeal Linings (meninges)
- Ventricles and Cerebrospinal Fluid
- Cerebrovascular System
Meningeal Linings
protective and circulatory systems
- Dura
- Arachnoid Mater
- Pia Mater
- Subdural space
- Subarachnoid space
Dura
Meningeal Linings
- outer layer
- tough membranous connective tissue
Arachnoid Mater
Meningeal Linings
-middle layer
Pia Mater
Meningeal Linings
- inner layer
- thin covering of tissue that adheres closely to the grooves and convolutions of the brain
subdural space
Meningeal Linings
located between the dura mater and the arachnoid
subarachnoid space
Meningeal Linings
- located between the arachnoid and pia mater
- filled with cerebrospinal fluid
Ventricles and Cerebrospinal Fluid
protective and circulatory systems
- Cerebrospinal Fluid
- Choroid Plexus
- Lateral Ventricles
- Interventricular foramen of Monroe
- Third Ventricle
- Cerebral Aqueduct
- Fourth ventricle
Cerebrospinal Fluid
Ventricles and Cerebrospinal Fluid
- cushion for the brain and spinal cord (protection and suspension)
- circulates nutrients and chemicals filtered from the blood
- removes waste products from the brain
choroid plexus
Ventricles and Cerebrospinal Fluid
-produces cerebrospinal fluid in ventricles
lateral ventricles
Ventricles and Cerebrospinal Fluid
- 2
- one in each hemisphere
- beginning ventricles for circulation of CFS
interventricular foramen of Monroe
Ventricles and Cerebrospinal Fluid
passageway between lateral ventricle and third ventricle
third ventricle
Ventricles and Cerebrospinal Fluid
1
cerebral aqueduct
Ventricles and Cerebrospinal Fluid
passage way between third ventricle and fourth ventricle
fourth ventricle
Ventricles and Cerebrospinal Fluid
- 1
- sends cerebrospinal fluid to subarachnoid space to circulate around brain and spinal cord
- cerebrospinal fluid is then absorbed by the venous system
hydrocephalus
- excessive accumulation of cerebrospinal fluid
- increases the size of the ventricles
- results in pressure on the brain
- variety of impairment of brain function
Cerebrovascular system - FUNCTION
protective and circulatory systems
- brain needs continuous supply of blood for the oxygen and glucose
- brain does not store the required oxygen and glucose
- interruptions of blood supply longer than a few minutes can cause permanent brain damage
Circle of Willis
cerebrovascular system
- series of points of communication between arteries
- equalizes blood pressure within the brain
- equalizes distribution of blood flow
1. anterior cerebral artery
2. middle cerebral artery
3. posterior cerebral artery
4. cerebellar artery
5. basilar artery
Anterior cerebral artery
circle of willis
- portions of the frontal and parietal lobes
- corpus callosum
- basal ganglia
middle cerebral artery
circle of Willis
- temporal lobe
- motor strip
- Brocas area
- Wernicke’s Area
- sensory reception regions
posterior cerebral artery
circle of willis
- portions of the temporal and occipital lobe
- upper midbrain
- cerebellum
cerebellar artery
circle of willis
cerebellum
basilar artery
circle of willis
brainstem
stroke- DISRUPTION OF BLOOD SUPPLY TO BRAIN
-Occurs when an artery to the brain is either blocked or burst
stroke- MAY CAUSE TEMPORARY OR PERMANENT DISABILITIES
- paralysis or weakness on one side of the body
- difficulty talking or swallowing
- memory loss or thinking difficulties
- emotional impairments
Cranial Nerves
I- Olfactory II- Optic III- Oculomotor IV- Trochlear V- Trigeminal VI- Abducens VII- Facial VIII- Vestibulocochlear IX- Glossopharyngeal X- Vagus XI- Accessory XII- Hypoglossal
Olfactory
cranial nerve
I
- function: sense of smell
- Type: sensory
- Damage: anosmia- loss of sense of smell and taste
Optic
cranial nerve
II
- Function: communicates visual information to the brain
- Type: Sensory
- Damage: various types of visual impairment depending on the location and severity of the damage along the nerve
Oculomotor
cranial nerve
III
Function: innervates eye movement (visual convergence and pupil size/lens shape)
Type: Motor
Damage: -Inability to turn the eye in
-drooping of the eyelid
-abnormal dilation of the pupil
Trochlear
cranial nerve
IV
Function: innervates eyes movement (visual tracking: downward and outward)
Type: Motor
Damage: inability to turn eye down and out
Trigeminal
cranial nerve
V
-Function:
Motor: innervates muscles of mastication, tensor veli palatini, tensor tympani
Sensory: communicates sensation from face, mouth, teeth mucosal lining and tongue
-Type: Both
- Damage:
- > increased jaw jerk reflex
- > jaw may deviate toward the side of the lesion
- > jaw may hang open- will effect speech
- > hypernasality in speech due to weakness or paralysis of tensor veli palatini muscle
- > loss or altered sensation from various locations of the face
Abducens
cranial nerve
VI
- Function: innervates eye movements (lateral eye movements)
- Type: Motor
- Damage: -eyes rotate in
- double vision
Facial
cranial nerve
VII
-Function:
Motor: innervates muscles of facial expression and tear glands
Sensory: serves taste of anterior two-thirds of tongue
-Type: Both
- Damage:
- > upper and lower face paralysis on the side of the lesion
- > loss of tone, reduction in wrinkling
- > may drool due to the loss of lip control
- > alteration of taste
Bells Palsy
compression of the facial nerve
Vestibulocochlear
cranial nerve
VIII
- Auditory nerve
- Function: Mediates auditory (hearing) information and vestibular (equilibrium) sensations
- Type: Sensory
- Damage: - Ipsilateral (same side) hearing loss
- Vertigo (feeling that you or your surrounding are moving)
Glossopharyngeal
cranial nerve
IX
-Function:
Motor: innervation of stylopharyngeus and superior pharyngeal constrictor
Sensory: Taste to posterior one-third of tongue and portion of the soft palate
-Type: Both
- Damage: -loss of sensation for posterior tongue and pharynx
- reduced or absent gag reflex
Vagus
cranial nerve
X
-Function:
Motor: Innervates muscles of the larynx used for phonation and protection of the airway, innervates all velopharyngeal muscles except the tensor veli palatini
Sensory: Delivers, pain touch a temperature sense from the eardrum, posterior auricle and external auditory meatus
- serves that autonomic nervous system (heart rate, blood pressure, digestion)
- Type: Both
- Damage:
- > dysphagia (difficulty swallowing)
- > loss of gag reflex
- > hyper nasality
- > nasal regurgitation
- > unilateral or bilateral flaccid vocal fold paralysis
- > risk for aspiration pneumonia
Accessory
cranial nerve
XI
- Function: activates sternocleidomastoid and trapezius muscles
- Type: motor
- Damage:
- > unable to turn head away from the side of the lesion
- > restricted ability to elevate the arm
- > drooping shoulder
Hypoglossal
cranial nerve
XII
- Function: innervates the muscles of the tongue
- Type: Motor
- Damage:
- > tongue will deviate toward the side of the lesion
- > fasciculation (abnormal involuntary twitching) of tongue
- > tongue muscle weakness
Traumatic brain injuries
- coup
- contrecoup
coup
Traumatic brain injury
injury at the site of impact
contrecoup
Traumatic brain injury
- injury opposite the site of impact
- linear and rotational movement of the brain within skull
