The Nervous System (NS) + Cranial Nerves (CN) Flashcards
What are the complex cells that make up the nervous sytem?
Neurons
What do neurons do?
Transmit information to and from the brain and spinal cord (SC) to various parts of your body
e.g. sensory information is brought into your brain; in turn, a motor response is sent out
Sensory in, motor out
Two major divisions of the NS
Central Nervous System (CNS
Peripheral Nervous System (PNS)
CNS
Include: brain + spinal cord
Brain - body’s computer
SC: Pathway for messages sent from the brain to the body and vice-versa
Peripheral Nervous System
CN and spinal nerves
CN: 12 pairs. About 7 are critical for speech production, voice, deglutition (swallowing), mastication (chewing), hearing, facial expression, and articulation
SN: 31 pairs. Some SN innervate the muscles of respiration
The brain is also called
The cerebrum or cortex
Externally the brain is what color
Gray in appearance - hence the name “gray matter”
Below the level of “gray matter” is white matter. This neural tissue is whitish in appearance.
Neural tissue below the gray matter is called
subcortical tissue
Majority of the brain is made up of subcortical tissue
Sulci (sulcus) + fissures
Looking at the surface of the brain, you can see sulci (plural)
sulcus (singular)
fissures
Some sulci have specific names and serve as landmarks on the surface of the brain
The brain is divided into two sides
Left and right hemispheres - called hemispheres or cerebral hemispheres
Each hemisphere responsible for different yet complementary functions, and both hemispheres communicate with each other to share information
most people who are right handed, the left hemisphere will be dominant for language functions - due to contralateral (opposite side of the body) innervation
L hemisphere will control the right side of the body and vice versa
Special band of fibers that join the hemispheres
corpus callosum
type of commissural fiber - they join the left and right hemisphere together
Specific Sulci that serve as landmarks
- Central sulcus - separates the frontal lobes from parietal
- Lateral sulcus - separates temporal lobe from the frontal and parietal lobes
- Parieto-occipital sulcus - separates the occipital lobe from the parietal lobes
- Precentral sulcus - immediately anterior to the central sulcus. it houses the primary motor area/cortex
- Postcentral sulcus - immediately posterior to the central sulcus. It houses the primary somatosensory or sensory area/cortex
Entire brain is encased in bone called?
Cranium
Actually made up of several bones that are joined by joints. These joints are synarthrodial joints (joints that do not move)
When a baby is born, these joints are not fused. The cranium is very malleable - it is cartilage. Babies are basically made up of cartilage and then, over time, this cartilage hardens into bone
Lobes of the brain
Frontal Lobes: 2, left and right. Most anterior of the lobes
Temporal Lobes: 2, L + R
Parietal Lobes: 2, L + R
Occipital Lobe: 2, L + R. Most posterior of the lobes
Primary vs. Association areas
Brain contains both throughout the cortex
Primary areas - make you aware of a stimulus
Association areas - allow you to interpret that stimulus
Frontal Lobes
Adult brains weigh about 3 lbs with frontal lobes (largest of all lobes) accounting for 40% of total weight of brain
Boundaries of the Frontal Lobes
Bound posteriorly by the central sulcus, inferiorly by the lateral sulcus, and anteriorly/superiorly by the outer surface of the brain
Left frontal lobe contains what area important for communication?
Broca’s area
Located in the 3rd left frontal convolution
Broca’s Area is responsible for?
motor programming or planning for speech production
It only PLANS the message. Sends it to the PRIMARY MOTOR CORTEX which sends the message to the muscles of articulation, telling them to contract
Broca’s area does not tell the muscles of articulation to contract or fire!
Precentral Sulcus
landmark of frontal lobes
houses the primary motor area/strip/cortex, which is the area that tells volitional or skeletal muscles to contract
In other words, it controls voluntary movement of skeletal or voluntary muscle, contralaterally
Functions of the Frontal lobes
They are responsible for attention and memory, motivation, personality, overall mood state, motor functions
Responsible for executive functions (EF)
Executive Functions
Higher level cognitive functions that mediate language function and that operate in the background. They are especially important when you complete novel or new tasks
Examples Executive Functions
- Memory + attention
- Impulse control or inhibition or self-regulation - ability to resist temptation
- selective attention
- planning and organization
- reasoning and judgment
- ability to consider pros + cons and outcomes
- ability to predict
- Mental or cognitive flexibility, including ability to think outside the box
- Knowledge of social rules and norms + knowledge of how they differ between events, settings, and with different types of people
- Problem solving - feasible or realistic problem solving
- set shifting
- response inhibition - STROOP TEST or STROOP EFFECT measures information processing speed and attention)
Damage to Frontal Lobes
Lobes are particularly susceptible to TBI
No other part of the brain where lesions can cause such a wide variety of impairments/problems
- personality changes, often significant
- irritability, depression, radical mood swings
- inability to follow social norms or rules
- lack of impulse control
- disinhibition - e.g. it’s too hot in the mall, takes all clothes off
- memory impairment along with deficits in attention and attentional control
- deficits in problems solving, reasoning/judgment, planning
- poor motivation
- addiction, changes in sexual behavior
Temporal Lobes
Located inferiorly to the parietal and frontal lobes
Boundaries: bound superiorly by the lateral sulcus and posteriorly by the parieto-occipital sulcus
Left Temporal Lobe houses what area important in communication?
Wernicke’s area - located on the superio temporal gyrus
Also, Heschl’s Gyrus
Two functions of Wernicke’s Area
- Responsible for comprehension of spoken language
- Responsible for formulation of linguistic thought
In other words, it thinks of the message that you ultimately want to say or speak
Wernicke’s area is an ASSOCIATION area - that is, it allows you to interpret what you have heard
Called AUDITORY ASSOCIATION CORTEX
Heschl’s Gyrus
Housed in left temporal lobe
lies along superior portion of the temporal lobe @ the lateral sulcus
Makes you AWARE that you heard something. It is a PRIMARY AREA, also called the PRIMARY AUDITORY CORTEX
Other functions of the temporal lobe
Memory, especially semantic memory + declarative memory
supports naming ability
reading, writing, word recognition skills
Facial recognition
Motivation
Seizure disorders are thought to come from problems in the temporal lobes
Help to process sensory information - taste, smell, sound
Help form long-term memories and process new information
prosodic comprehension
plays a role in social cognition
plays a role in overall mood state - damage can produce apathy, aggressive behavior including sexual aggression, passivity, indifference, rage
Parietal Lobes
Form the rounded roof of the cranium and are immediately posterior to the frontal lobes
Boundaries:
Bound anteriorly by the central sulcus
Bound superiorly by the roof of the cranium
Bound inferiorly by the lateral sulcus
Bound posteriorly by the parieto-occipital sulcus
What important area do the parietal lobes house?
Primary sensory area or somatosensory area
Area is contained within the posterior central gyrus or postcentral sulcus
What does the somatosensory area do?
Makes you aware of different sensations such as touch, pain, temperature, visual integration, taste. Especially important to TOUCH
Responsible for PROPRIOCEPTION or the knowledge of where your body is in space. proprioception allows you to carry out motor functions without having to watch your limbs
Other functions of the parietal lobes
math skills
spatial skills, spatial orientation/judgment
lesion can alter body image
supports memory
personality
lesion can produce an unusual phenomena called left-side neglect
Lesion can produce agnosia - inability to interpret sensations, to recognize things such as objects, other people, pictures
Occipital Lobe
Most posterior of all the lobes. They are also the smallest
They contain the PRIMARY VISUAL CORTEX and the VISUAL ASSOCIATION CORTEX
Primary Visual Cortex
Makes you aware that you have seen something
Visual Association Cortex
Allows you to interpret what you have seen
Damages to the Occipital Lobe
can interfere with the ability to process visual information
This might be in the form of a worksheet, looking @ pictures, or any other visual stimuli that we might give to a person to process in the context of treatment or evaluation
Brainstem
Tube-shaped mass that is situated at the base of the brain, just superior to the spinal cord
It articulates with the spinal cord so that it can control the flow of neural impulses (messages or information) between the brain and the rest of the body
Brainstem is regarded as a primitive structure that is not involved in any higher level thinking or cognition
3 Major parts of the brainstem
Responsible for life-sustaining functions
- Medulla oblongata
- Pons
- Midbrain
Medulla Oblongata
Most inferior portion of the brainstem
Regulates ALL life-sustaining functions, including respiration, heartbeat, blood pressure, and digestion
Regulates sweating, temperature, sleep cycles, alertness, and balance
Responsible for many reflexes in the body or involuntary controls, such as vomiting, sneezing, and coughing
Damage to this particular area is imminently life-threatening or life-ending
Medulla Oblongata houses the nuclei for the following CN (cranial nerves)
- IX Glossopharyngeal
- X Vagus
- XI Accessory
- XII Hypoglossal
Random fact about Medulla Oblongata
The area postrema is an area along the dorsal portion of the medulla oblongata that is responsible for VOMITING or EMESIS
This area is absent in rats. That is why rat poisoning is effective - rats can’t throw up after they ingest
The Brainstem - Pons
Pons literally means bridge
It serves as a bridge to connect the medulla oblongata and the midbrain
Other functions: transmits signals to/from other structures in the brain, such as the cerebrum or the cerebellum. Helps in the regulation of some sensations such as hearing, taste, and balance. Also helps in the regulation of deep sleep.
What is the most important function fulfilled by the PONS?
Regulation of RESPIRATION or breathing
Houses structure called the PNEUMOTAXIC CENTER
This center controls the amount of air that is breathed and the number of breaths per minute - also known as the breathing rate
The Pons houses the nuclei for the following CN
- V Trigeminal
- VI Abducens
- VII Facial
- VIII Auditory/Vestibulocochlear
Brainstem - Midbrain
Most SUPERIOR portion of the brainstem
Serves as a relay center for visual, auditory, and motor system information
Also regulates autonomic functions - those that the body carries out without conscious thought - such as digestion, heart rate, and breathing rate
The midbrain houses nuclei for the following CN
III oculomotor
IV trochlear
Cerebellum
Situated at the base of the brain, just posterior to the brainstem
Like the cerebrum, the cerebellum is also comprised of two hemispheres
Functions of Cerebellum
Responsible for smooth, graded, flowing, coordinated movements, including those used in speech production.
Maintains overall tone and truncal tone (type of muscle tone in the trunk)
Important in posture, balance, coordination.
Regulates force and timing of movements
Cranial Nerves (CN)
There are 12 pairs of CN of which 7 are highly relevant to clinical practice in both speech-language pathology and audiology
CN are always referred to by NAME and/or ROMAN NUMERAL. Referring to CN X Vagus as CN 10 would be incorrect
All but TWO of the CN arise from the brainstem and exit the brain
CN
I - Olfactory
II - Optic
III - Oculomotor
IV - Trochlear Accessory
V - Trigeminal
VI - Abducens
VII - Facial
VIII - Auditory or Vestibulocochlear
IX - Glossopharyngeal
X - Vagus
XI - Accessory or Spinal
XII - Hypoglossal
Odor of Orangutang Terrified Tarzan After Forty Vicious Gorillas Voraciously Attacked Him
Odor of Orangutang Terrified Tarzan After Forty Vicious Gorillas Voraciously Attacked Him
Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear, glossopharyngeal, vagus, accessory, hypoglossal
CN are either ____ or _____ or ______
Sensory or Motor or Both
Sensory means that a nerve is responsible for bringing sensory information to the brain for processing
MOTOR means that a nerve is responsible for sending out a neural signal that tells a muscle to fire or contract
ALL CN are paired
Mnemonic Device for Sensory or Motor:
Some Say Marry Money, But My Brother Says Big Brains Matter Most
CN I: Olfactory - Sensory only for smell
CN II: Optic
Sensory only for vision. Transmits information from the eye to the brain for processing. It’s the primary nerve of sight
CN III: Oculomotor
Motor Only. Innervates those muscles that move the eyes and that allow the pupils to constrict
CN IV: Trochlear
Motor only. Also aids in eye movements
CN V: Trigeminal.
Sensory and Motor. Mastication, swallowing, + protection of the ear from excessively loud noises. Assists with soft palate elevation
CN VI: Abducens.
Motor only Abducts (moves away from mideline, towards the temporal bone) the eyes
CN VII: Facial.
Sensory and Motor. Muscles of facial expression, sensory for the tongue + palate
CN VIII: Auditory.
Sensory only. Sense of hearing and for balance/equilibrium
CN IX: glossopharyngeal
. Sensory and Motor. Assistant to CN X Vagus. Motor for deglutition. Sensory for larynx, pharynx, tongue, EAM
CN X: Vagus.
Sensory and Motor. Motor for larynx, pharynx, velum + digestion, cardiovascular function. Sensory for larynx, pharynx, tongue root, epiglottis, and for heart/abdominal viscera [viscera - large internal organs]
CN XI: Accessory or Spinal Accessory.
Motor only. Assistant to CN X. Also, head turning, tilting, and shoulder extension.
CN XII: Hypoglossal.
Motor only for extrinsic and intrinsic muscles of the tongue
