CH. 1: Anatomy Flashcards
Medulla Oblongata
Area in the brainstem that fires impulses to the respiratory muscles to spur respiration.
Bronchi
Tubes that extend from the lungs upward to the trachea. Composed of cartilaginous rings bound together by fibroelastic tissue.
Bronchioles
Subdivisions of the bronchi.
Alveolar Ducts
Communicate with the bronchioles. Where gas exchange occurs.
C1 – C7
Seven cervical vertebrae.
T1 – T12
Twelve thoracic vertebrae.
L1 – L5
Five lumbar vertebrae.
S1 – S5
Five sacral vertebrae.
Coccyx
Three to four coccygeal vertebrae that are fused together.
Sternum
Bone located on the superior, anterior thoracic wall. Consists of the manubrium, body/corpus, and xiphoid process.
Manubrium
Uppermost segment of the sternum. Provides attachment for the clavicle and first rib.
Corpus/Body
Segment of the sternum that is long and narrow. Attaches to the cartilages of ribs 2 – 7.
Xiphoid Process
Small cartilaginous structure found at the bottom of the body of the sternum.
Thoracic Cage
Consists of 12 pairs of ribs that form a cylindrical structure, the sternum, and 12 thoracic vertebrae (T1 – T12). Also known as the chest or rib cage.
Diaphragm
The floor of the chest cavity. Thick, dome-shaped muscle that separates the abdomen from the thorax. Plays a major role in breathing. Distends abdomen. Enlarges vertical dimension of thorax. C3 – C5.
Abdomen
Houses structures such as the intestines, liver, and kidneys. Muscles from this area are critical in providing support for breathing.
Intercostal Muscles
Muscles located between the ribs. Critical for respiration.
Internal Intercostal Muscles
11 paired muscles that pull the ribs downward to decrease the diameter of the thoracic cavity for EXHALATION.
External Intercostal Muscles
11 paired muscles that raise the ribs up and out to increase the diameter of the thoracic cavity for INHALATION.
Muscles involved in Rib Cage Elevation
Serratus posterior superior (C7, T1 – T4), levator costarum brevis (T2 – T12), levator costarum longus (T2 – T12), external intercostals (T2 – T11). Thoracic muscles. Involved in inspiration.
Accessory Muscles of the Neck
Thoracic muscle group composed of the sternocleidomastoid and the trapezius. Involved in the process of respiration.
Sternocleidomastoid Muscle
Elevates the sternum, indirectly elevating the rib cage. Involved in inspiration.
Trapezius Muscle
Controls the head and elongates the neck, indirectly influencing respiration. Involved in inspiration.
Muscles of the Shoulder & Upper Arm
Thoracic muscles that act to move the rib cage and increase or decrease its dimensions. Includes the pectoralis major, pectoralis minor, serratus anterior, and levator scapulae. Involved in inspiration.
Pectoralis Major
Increases transverse dimension of rib cage through elevation of sternum. C4 – T1. Involved in inspiration
Pectoralis Minor
Increases transverse dimension of rib cage. Located from C4 – T1. Involved in inspiration.
Serratus Anterior
Elevates ribs 1 – 9. C5 – C7. Involved in inspiration.
Levator Scapulae
Elevates scapula and supports neck. C3 – C5. Involved in inspiration.
Muscles involved in Stabilizing Shoulder Girdle
1) Rhomboideus major (C5)
2) Rhomboideus minor (C5).
Involved in inspiration.
Muscles involved in Rib Cage Depression
1) Internal intercostals (T2 – T11)
2) Innermost intercostals (T2 – T11)
3) Transversus thoracicus (T2 – T6)
Thoracic muscles. Involved in inspiration.
Subcostal Muscles
Depresses the thorax. Involved in exhalation.
Serratus Posterior Inferor Muscles
Thoracic muscles that pull the rib cage down when contracted. Involved in exhalation.
Muscles of Expiration
1) Latissmus dorsi
2) Rectus abdominus
3) Transversus abdominis
4) Internal oblique abdominis
5) Quadrus lumborum
Latissimus Dorsi
Abdominal muscle that stabilizes the posterior abdominal wall for expiration.
Rectus Abdominis
Abdominal muscle that flexes vertebral column. T7 – T12. Involved in expiration.
Transversus Abdominis
Abdominal muscle that compresses abdomen. T7 – T12. Involved in expiration.
Internal Oblique Abdominis
Abdominal muscle that compresses abdomen, and flexes and rotates trunk of body. T7 – T12. Involved in expiration.
Quadratus Lumborum
Abdominal muscle that supports abdominal compression through bilateral contraction, which fixes abdominal walls. T12, L1 – L4. Involved in expiration.
Larynx
Lies at the top of the trachea in the anterior portion of the neck. A valving mechanism that opens and closes. Houses the vocal folds.
Vocal Folds
Vibrate by adducting and abducting to produce sound. Housed in the larynx.
Biological Functions of the Larynx
1) Airway protection from food and liquid
2) Production of cough reflex for protection
3) Closure of VF to build subglottic pressure to bear down
Hyoid Bone
U-shaped bone that floats under the mandible. Attached to the muscles of the mandible, skull, and larynx.
Epiglottis
A leaf-shaped, protective structure made of cartilage medial to the thyroid cartilage and hyoid bone. During swallowing, this structure drops to cover the orifice of the larynx.
Thyroid Cartilage
Forms the anterior and latral walls of the larynx and protects the larynx.
Cricoid Cartilage
Cartilage that completely surrounds the trachea. Linked with the thyroid cartilage and paired arytenoid cartilages. Sometimes referred to as the uppermost tracheal ring.
Arytenoid Cartilages
Small, pyramid-shaped cartilages connected to the cricoid through the cricoarytenoid joint, which permits sliding and circular movements.
Corniculate Cartilages
Small, cone-shaped cartilages that sit on the apex of the arytenoids. Assist in reducing the laryngeal opening when a person is swallowing.
Cuneiform Cartilages
Tiny, cone-shaped cartilages located under the mucous membrane that covers that aryepiglottic folds. Serve to stiffen or tense the aryepiglottic folds.
Intrinsic Laryngeal Muscles
Muscles primarily responsible for controlling sound production. Includes the thyroarytenoid, lateral cricoarytenoid, transverse arytenoid, oblique arytenoid, cricothyroid, and posterior cricoarytenoid. Have one attachment inside the larynx.
Thyroarytenoid
Laryngeal muscle attached to the thyroid and arytenoid cartilages. Divided into the internal and external masses of this muscle.
Internal Thyroarytenoid
Primary portion of the thyroarytenoud muscle that vibrates and produces sound. Generally referred to as the vocalis muscle or vocal folds.
Laryngeal Adductor Muscles
Includes the lateral cricoarytenoid, transverse arytenoid, and oblique arytenoid. Muscles that bring the vocal folds together.
Cricothyroid Muscle
Laryngeal muscle attached to the cricoid and thyroid cartilages. Lengthens and tenses the VF. Innervated by CN X.
Lateral Cricoarytenoid
Adducts VF and increases medial compression. Innervated by CN X.
Transverse Arytenoid
Adducts VF. Innervated by CN X.
Oblique Arytenoid
Pulls apex of arytenoids in a medial direction. Innervated by CN X.
Posterior Cricoarytenoid
Abducts VF. Innervated by CN X.
Extrinsic Laryngeal Muscles
Muscles that support the larynx and fix its position. Have one attachment inside the larynx and one attachment outside the larynx.
Extrinsic Laryngeal Elevators/Suprahyoid Muscles
Muscles that lie above the hyoid bone. Primary function is elevation of the larnx. Includes the digastric (V, VII), geniohyoid (XII, C1), mylohyoid (V), stylohyoid (VII), hyoglossus (XII), and genioglossus (XII).
Extrinsic Laryngeal Depressors/Infrahyoid Muscles
Muscles that lie below the hyoid bone. Primary function is depression of the larynx. Includes the thyrohyoid (XII, C1), omohyoid (C1 – C3), sternothyroid (C1 – C3), and sternohyoid (C1 – C3).
3 Layers of VF
Epithelium, lamina propria, and vocalis muscle.
Epithelium
Outer cover of the VF.
Lamina Propria
Middle layer of the VF. Has its own 3 layers.
Aryepiglottic Folds
Composed of a ring of connective tissue and muscle extending from the tip of the arytenoids to the larynx. They separate the laryngeal vestibule from the pharynx and help preserve the airway.
Ventricular/False VF
Vibrate only at very low fundamental frequencies and usually not during phonation in a normal speaker. Compress during activities such as coughing and lifting heavy items.
Myoelastic-Aerodynamic Theory
States that the VF vibrate because of the forces and pressure of air and the elasticity of the VF.
Bernoulli Effect
The “sucking” motion of the VF toward one another, caused by the increased speed of air passing between the VF.
Mucosal Wave Action
The cover (epithelium and superficial lamina propria, also called Reinke’s space) and the transition (intermediate and deep layers of the lamina propria) over the vocalis muscle slide and produce a wave. Critical to the vibration of the VF.
Primary Cortical Areas involved in Speech-Motor Control
Cortical areas 4 (primary motor cortex), 44 (Broca’s area), 3, 1, 2 (somatosensory cortex), and area 6 (supplementary motor cortex).
Cerebellum
Regulates motor movement. Critical in the control of speech movement. Key to the coordination of the laryngeal muscles for adequate phonation. Key to effective functioning of other speech systems such as respiration.
Branches of CN X
Superior laryngeal nerve (SLN) and recurrent laryngeal nerve (RLN).
Superior Laryngeal Nerve
Has internal and external braches. Internal branch provides sensory information to the larynx. External branch supplies motor innervation to the cricothyroid muscle.
Recurrent Laryngeal Nerve
Supplies all motor innervation to the interarytenoid, posterior cricoarytenoid, thyroarytenoud, and lateral cricoarytenoid muscles. Supplies all sensory information below the VF.
Key Neuroanatomical Structures involved in Vocalization
Cortical areas, the cerebellum, CN VII (facial nerve) and CN X (vagus nerve).
Resonation
The process by which the voice, or laryngeal tone, is modified when some frequency components are dampened and others are enhanced. This system is composed of the pharynx, nasal cavity, and oral cavity.
Pharynx
Part of the upper airway. Located superiorly and posteriorly to the larynx. Size and shape of this structure are modified by the positon of the tongue in the mouth (forward or back) and the vertical positioning of the larynx in the neck (high or low).
Nasal Cavity
Area with an important role in resonation. Sounds /m, n, ng/ are produced here. During the production of sounds in this area, the soft palate (velum) is relaxed and lowered. Couples with the oral cavity.
Velum
Structure that is elevated and retracted for all sounds (other than nasals) in English. During production of these sounds, this structure is raised and retracted (moved back) to make contact with the posterior pharyngeal wall, separating the oral cavity from the nasal cavity. Thus the cavities are uncoupled. Sounds produced with this structure primarily utilize oral resonation.
Oral Cavity
The primary resonating structure for all English sounds (other than nasals).
Source-Filter Theory
According to this theory, the vocal tract is visualized as a series of linked tubes: the mouth, pharynx, and nasal cavity. These linked tubes provide the variable resonating cavity that helps produces speech. States that energy from the vibrating VF (the source) is modified by the resonance characteristics of the vocal tract (the filter).
Articulation
Refers to the movement of joined anatomic parts as well as the production of speech sounds that result from such movements.
Segments of the Pharynx
1) Laryngopharynx
2) Oropharynx
3) Nasopharynx
Laryngopharynx
Segment of the pharynx which begins immediately superior to the larynx and ends at the base of the tongue. Connected to the oropharynx.
Oropharynx
Segment of the pharynx which extends up to the soft palate. Connected to the nasopharynx.
Nasopharynx
Segment of the pharynx which ends where the two nasal cavities begin.
Salpingopharyngeus
Elevates pharyngeal wall. Innervated by CN X and XI.
Stylopharyngeus
Elevates and opens pharynx. Innervated by CN IX.
Superior Pharyngeal Constrictor
Constricts pharyngeal diameter and pulls pharyngeal wall forward. Innervated by CN X and XI.
Middle Pharyngeal Constrictor
Narrows diameter of pharynx. Innervated by CN X and XI.
Inferior Pharyngeal Constrictor, Cricopharyngeus
Constricts superior orifice of esophagus. Innervated by CN X and XI.
Inferior Pharyngeal Constrictor, Thyropharyngeus
Reduces diameter of lower larynx. Innervated by CN X and XI.
Soft Palate/Velum
A flexible muscular structure at the juncture of the oropharynx and the nasopharynx. Located in the posterior area of the oral cavity and hangs from the hard palate. Dynamic structure of muscles that can elevated or lowered.
Uvula
Small, cone-shaped structure at the tip of the velum.
Velopharyngeal Closure
Occurs when the soft palate is raised and retracted and the muscles of the pharynx also move inward to meet the muscles of the soft palate. A sphincter-like action.
Muscles of the Soft Palate/Velum
Includes the levator veli palatine, tensor veli palatine, palatoglossus, and palatopharyngeus.
Levator Veli Palatini
Primary elevator of velum. Innervated by CN X and XI.
Tensor Veli Palatini
Tenses velum and dilates the Eustachian tube. Innervated by CN V.
Palatoglossus
Elevates and depresses the velum. Innervated by CN X and XI.
Palatopharyngeus
Narrows the pharyngeal cavity and lowers the velum. May assist in elevating the larynx. Innervated by CN X and XI.
Hard Palate
Hard, bony roof of the mouth and the base of the nasal cavity. Part of the maxillae.
Premaxilla
Frontal portion of the maxillary bone. Houses the four upper front teeth (incisors).
Palatine Process
Portion of the maxillary bone that forms the most of the hard palate. Consists of two pieces of bone that grow and fuse at the midline during the fetal stage.
Alveolar Process
Outer edges of the maxillary bone. Houses the molar, bicuspid, and cuspid teeth.
Palatine Bone
Fuses with the maxillary bone posteriorly. The soft palate attaches to this bone.
Mandible
Lower jaw. Houses the lower teeth and forms the floor of the mouth. Formed by the fusion of two bones in the midpoint of the chin, but is considered to be one bone in adults.
Temporomandibular Joint
The mandible is attached to the temporal bone of the skull by this joint.
Functions of Mandibular Muscles
1) Opening and closing the mouth
2) Chewing food
Mandibular Elevators
Masseter (CN V), temporalis (CN V), medial (internal) pterygoid (CN V), and lateral (external) pterygoid (CN V).
Mandibular Depressors
Anterior belly of digastric (CN V), posterior belly of digastric (CN VII), geniohyoid (CN XII, C1), and mylohyoid (CN V).
Deciduous Teeth
“Baby” teeth. Babies normally have 20 of these, 10 in each arch. Of the 10, 4 are incisors, 2 are canine, and 4 are molar.
Occlusion
Refers to the way the two dental arches come together when a person “bites down.” Considered normal if the upper and lower dental arches meet each other in a symmetric manner and if the individual teeth in the two arches are properly aligned.
Malocclusions
Include deviations in the positioning of individual teeth and the shape and relationship of the upper and lower dental arches.
Parts of the Tongue
Tip, blade, dorsum, and root.
Tip of the Tongue
Thinnest, most flexible part of the tongue. Plays an important role in articulation.
Blade of the Tongue
A small region adjacent to the tip of the tongue. In a resting position, this area is the portion of the tongue that lies just inferior to the alveolar ridge.
Dorsum of the Tongue
The large area of the tongue that lies in contact with both the hard and soft palates.
Root of the Tongue
The very back and bottom portion of the tongue.
Lingual Frenulum
Connects the mandible with the inferior portion of the tongue. This band of tissue may stabilize the tongue during movement.
Intrinsic Lingual Muscles
1) Superior longitudinal muscle (XII)
2) Inferior longitudinal muscle (XII)
3) Transverse muscles (XII)
4) Vertical muscles (XII)
Superior Longitudinal Muscle
Shortens the tongue, turns tip upward, assists in turning lateral margins upward. Innervated by CN XII.
Inferior Longitudinal Muscles
Shortens the tongue, pulls tip downward, and assists in tongue retraction. Innervated by CN XII.
Transverse Muscles (of the Tongue)
Narrow and elongate the tongue. Innervated by CN XII.
Vertical Muscles (of the Tongue)
Flattens the tongue. Innervated by CN XII.
Extrinsic Lingual Muscles
1) Genioglossus (XII)
2) Styloglossus (XII)
3) Hyoglossus (XII)
4) Chondroglossus (XII)
5) Palatoglossus
Genioglossus
Forms bulk of the tongue. Is able to retract the tongue, draw tongue downward, draw entire tongue anteriorly to protrude tip or press tip against alveolar ridges and teeth. Bulk of the tongue. Allows tongue to move freely. Innervated by CN XII.
Styloglossus
Draws tongue up and back. May draw sides of tongue upward to help make dorsum concave. Innervated by CN XII.
Hyoglossus
Retracts and depresses the tongue. Innervated by CN XII.
Chondroglossus
Depresses the tongue. Innervated by CN XII.
Palatoglossus
Some consider it a muscle of the velum, but it helps elevate the tongue while depressing the velum.
Orbicularis Oris (Inferioris & Superioris)
Primary muscle of the lips. Pulls lips together, seals lips, serves as point of insertion for other muscles, and interacts with other muscles to produce facial expressions. Innervated by CN VII.
Buccinator
Primary muscle of the cheeks. Large, flat muscle whose inner surface is covered with mucous membrane. Constricts the oropharynx. Moves food onto grinding surfaces of molar. Innervated by CN VII.
Mentalis
Pulls lower lip out and wrinkles and elevates the chin. Pouting. Innervated by CN VII.
Platysma
Facial muscle that depresses mandible. Innervated by CN VII.
Risorius
Retracts lips at corners. Smiling/lip spreading. Innervated by CN VII.
Depressor Labii Inferioris
Pulls lip down and out to dilate orifice. Innervated by CN VII.
Depressor Anguli Oris (Triangularis)
Help to press lower and upper lips together. Depresses corners of the mouth. Innervated by CN VII.
Upper Lip Elevators
1) Zygomatic minor (CN VII)
2) Levator Labii Superioris (CN VII)
3) Levator Labii Superioris Alaeque Nasi (CN VII)
Zygomatic Major
Retracts and elevates angle of the mouth. Innervated by CN VII.
Levator Anguli Oris
Draws corner of mouth upward and toward medial. Innervated by CN VII.
Glial Cells/Neuroglia
Cells related to myelin production. Includes Schwann cells and oliodenroglia.
Microglia
Cells that act as scavenges to remove dead cells and other waste.
Neurons
The most important type of nerve cells. Billions of these are located in the body. Receive information from other cells, process that information, and then transmit the information to the other cells. Composed of two parts: Nerve fibers and the soma (body).
Soma
Holds the nucleus. Cell body.
Nucleus
Core of the cell body. Covered with a membrane.
Axons
Send out impulses generated within the neuron. These impulses are sent away from the cell body to other neurons. Projections of the cell body. Specialize in receiving and conducting stimuli. Each cell only has one of these. Wrapped in a myelin sheath. Long and have terminal/end buttons on the tip.
Dendrites
Short fibers that extend from the cell body. Receive neural impulses generated from the axons and other cells, and they transmit those impulses to the cell body.
Synapses
Junctions that allow neurons to communicate with each other. Consists of the terminal button of one neuron, the receptive site of another neuron, and the synaptic cleft or space between the two.
Synaptic Cleft
Space between the terminal button and receptive sites of two neurons.
Neural Transmission
A chemical process of information exchange at the level of the synapse.
Neurotransmitter
Chemical contained within the terminal buttons that helps make contact between two cells by diffusing itself across the synaptic cleft. Dopamine and acetylcholine are important types found in the motor system.
Types of Neurons
1) Motor neurons
2) Sensory neurons
3) Interneurons
Sensory Neurons
Carry sensory impulses from the peripheral sense organs toward the brain. Afferent neurons.
Motor Neurons
Transmit impulses away from the central nervous system. Cause glandular secretions or muscle contractions (movement). Efferent neurons.
Interneurons
Link neurons with other neurons. Because they form connections with other neurons, these neurons play an important role in controlling movement. The most common type of neuron.
Myelin
White insulating sheath around axons. Has breaks at the junction between the cells to facilitate the impulse transfer.
Nervous System
An organization of nerves according to specific spatial, structural, and functional principles.
Peripheral Nervous System (PNS)
A collection of nerves that are outside of the skull and spinal column. These nerves carry sensory impulses from organs to the brain, and motor impulses originating in the brain to the glands and muscles of the body. Contains three types of nerves: cranial, spinal, and autonomic nerves.
Cranial Nerves
Emerge from the brainstem and are attached to the base of the brain. Part of the lower motor system, and they receive most of their innervations from the corticobulbar tract of the pyramidal system. Exit through foramina in the base of the skill. They exit through different levels of the brainstem and the top portion of the spinal cord. Nerves most directly involved in speech, language, and hearing.
Foramina
Holes in the skull.
Sensory Nerves
Cranial nerves that carry sensory innervation from a sense organ (like the nose) to the brain.
Motor Nerves
Cranial nerves that carry impulses from the brain to the muscles that make those muscles move.
Mixed Nerves
Cranial nerves that carry both sensory and motor impulses.
Olfactory Nerve (I)
Sense of smell (sensory). CN.
Optic Nerve (II)
Vision (sensory). CN.
Oculomotor Nerve (III), Trochlear Nerve (IV) & Abducens Nerve (VI)
Eye movement (motor). 3 CNs.
Trigeminal Nerve (V)
Face (sensory). Jaw (motor). CN. Its sensory nerves have three branches: opthalamic, maxillary, and mandibular branches. Its motor fibers innervate various jaw muscles. Damage may result in inability to close the mouth, difficult in chewing, and trigeminal neuralgia (sharp pain in the facial area).
Facial Nerve (VII)
Tongue (sensory). Face (motor). CN. Sensory fibers are responsible for taste sensations on the anterior 2/3 of the tongue. Motor fibers innervate muscles important to facial expression and speech. Damage gives the face a mask-like appearance with little or no facial expression.
Acoustic Nerve (VIII)/Vestibulocochlear Nerve
Hearing and balance (sensory). CN. Transmits sensory information from the cochlea of the inner ear to the primary auditory cortex of the brain, where it is interpreted. Damage to this area can cause hearing loss or problems with balance.
Glossopharyngeal Nerve (IX)
Tongue and pharynx (sensory). Pharynx only (motor). CN. Sensory components assists in processing taste sensations from the posterior 1/3 of the tongue. Provides general sensation for the tympanic cavity, ear canal, ET, faucial pillars, tonsils, soft palate, and pharynx. Motor component innervates the stylopharyngeus, which raises and dilates the pharynx. Damage to this nerve may create difficulty swallowing, unilateral loss of the gag reflex, and loss of taste and sensation from the posterior 1/3 of the tongue.
Vagus (X)
Larynx, respiratory, cardiac, and gastrointestinal systems (sensory and motor). CN. Sensory fibers convey information from the digestive system, heart, trachea, pharynx, and larynx. Motor fibers supply the digestive system, heart, and lungs. Has RLN branch and pharyngeal branch Damage can lead to difficulty swallowing, paralysis of the velum, and voice problems if RLN is damaged.
Spinal Accessory (XI)
Shoulder, arm, and throat movements (motor). CN. Innervates the uvula and levator veli palatini muscles of the soft palate. Damage can lead to neck weakness, paralysis of the sternocleidomastoid, inability to turn head, inability to shrug shoulder or raise arms above shoulder level.
Hypoglossal (XII)
Mostly tongue movements (motor). CN. Supplies styoglossus, hyoglossus, and genioglossus. Also supplies all intrinsic muscles of the tongue. Damage can result in tongue paralysis, diminished intelligibility, and swallowing problems.
CNs NOT involved in SLH
1) Olfactory (I)
2) Optic (II)
3) Oculomotor (III)
4) Abducens (VI)
CNs involved in SLH
1) Trigeminall (V)
2) Facial (VII)
3) Acoustic (VIII)
4) Glossopharyngeal (IX)
5) Vagus (X)
6) Spinal Accessory (XI)
7) Hypoglossal (XII)
Ophthalmic Branch of CN V
Branch of CN V with sensory branches to the nose, eyes, and forehead.
Maxillary Branch of CN V
Branch of CN V with sensory branches to the upper lip, maxilla, cheek area, upper teeth, maxillary sinus, and palate.
Mandibular Branch of CN V
Branch of CN V with sensory branches to the mandible, lower teeth, lower lip, tongue, part of the cheek, and part of the external ear.
Pharyngeal Plexus
Innervates the upper pharyngeal constrictor muscles. Composed of glossopharyngeal nerve (CN IX) and vagus nerve (X).
Recurrent Laryngeal Nerve (RLN)
Branch of the Vagus nerve (CN X) that regulates the intrinsic muscles of the larynx. May be damaged during thyroid surgery, resulting in paralysis of the VF.
Pharyngeal Nerve
Branch of the Vagus nerve (CN X) that supplies the pharyngeal constrictors. Supplies all muscles of the velum except the tensor tympani.
Spinal Nerves
Nerves of the PNS that are closely related to the ANS. Together, they control various bodily activities that are executed with little conscious effort or knowledge. Can be sensory, motor, or mixed. Transmit motor information from the CNS to the muscles. Carry sensory information from peripheral receptors to the CNS. 31 pairs. Attached to the spinal cord through two roots: efferent and ventral root, and afferent and dorsal root.
Conis Medullaris
Where the spinal cord ends at the LI vertebra level.
Cauda Equina
Lowermost nerves in the spinal structure.
Filum Terminale
Area in the spinal structure where there are no spinal cord segments.
Autonomic Nervous System (ANS)
Controls and regulates the internal environment for our body (like the heartbeat). Part of the PNS. Has two branches: Sympathetic and parasympathetic.
Branches of the ANS
1) Sympathetic
2) Parasympathetic
Sympathetic Branch of the ANS
Mobilizes body for “fight or flight” situations. Activation of this branch accelerates the heart rate, dilates the pupil, raises the blood pressure, and increases the blood flow to peripheral body structures (e.g., lugs running from danger). Can cause emotional arousal.
Parasympathetic Branch of the ANS
Helps bring the body back to a state of relaxation. After highly-charged situations, lower BP, slows heart rate, increases stomach activity, and generally relaxes the body.
Brainstem
Connects the spinal cord with the brain via the diencephalon. Serves as a bridge between the cerebellum and all other CNS structures, including the spinal cord, thalamus, basal ganglia, and cerebellum. Consists of longitudinal fiber tracts, cranial nerve nuclei, and the reticular formation. Key structures include the midbrain, pons, and the medulla.
Midbrain/
Mesencephalon
A narrow structure that lies superior to the pons and inferior to the diencephalon. Has superior peduncles and the substantia nigra. Its structures control many motor and sensory functions, including postural reflexes, visual reflexes, eye movements, and coordination of vestibular-generated eye and head movement. Contains the cranial nerve nuclei for the trochlear (CN VI) and oculomotor (CN III) nerves, although not involved in speech production.
Superior Peduncles
Help connect the brainstem and the cerebellum.
Substantia Nigra
Runs the vertical length of the midbrain at the level of the peduncles. MORE DETAIL.
Pons/Metencephalon
A roundish, bulging structure that bridges the two halves of the cerebellum. Located inferior to the midbrain. Transmits information relative to movements from the cerebral hemispheres to the cerebellum. Contains many descending motor fibers and is involved with hearing and balance. Houses the nuclei for the trigeminal nerve (CN V) and facial nerve (CN VII), which are important for speech production.
Medulla/Myelencephalon
Inferior to the midbrain and pons. It is the uppermost portion of the spinal cord, which enters the cranial cavity through the foramen magnum at the base of the skull. Contains all the fibers that originate in the cerebellum and cerebrum and move downward to form the spinal cord. Includes service centers that control vital, automatic bodily functions such as breathing, digestion, heart rate, and blood pressure. Very important for speech production because it contains descending fibers that transmit motor information to several cranial nerve nuclei. Contains nerve fibers (pyramidal tracts) that carry commands from the motor center of the brain to various muscles.
Foramen Magnum
Hole in the base of the skull where the medulla enters.
Reticular Activating System (RAS)
A structure within the midbrain, brainstem, and upper portion of the spinal cord. Integrates motor impulses flowing out of the brain with sensory impulses flowing into it. Plays a role in the execution of motor activity. Sends diffuse impulses to various regions of the cortex and alters the cortex to incoming impulses. Primary mechanism of attention and consciousness. Important in controlling the sleep-wake cycles.
Diencephalon
Lies above the midbrain and between the brainstem and the cerebral hemispheres. Contains the third ventricle, thalamus, and hypothalamus.
Third Ventricle
A tall and narrow space filled with cerebrospinal fluid.
Thalamus
Critical for maintenance of consciousness and alertness. Regulates the sensory information that flows into the brain and relays sensory impulses to various portions of the cerebral cortex. Receives information about motor impulses from the cerebellum and the basal ganglia and relays this information to the motor areas of the cerebral cortex. Largest structure in the diencephalon.
Hypothalamus
Helps integrate the actions of the ANS. Controls emotions. Lies inferior to the thalamus.
Basal Ganglia
A highly complex system of neural pathways that have connections with many subcortical and cortical areas. Receive input primarily from the frontal lobe and relay information back to the higher centers of the brain via the thalamus. Encompasses structures deep within the brain that are located near the thalamus and lateral ventricles. Consists of the globus pallidus, putamen, and caudate nucleus. Part of the extrapyramidal system. Lesions in this area can result in unusual body postures, dysarthria, changes in body tone, and involuntary and uncontrolled movements that interfere with a person’s ability to walk, speak, or do many other voluntary activities.
Corpus Striatum
Term that includes the globus pallidus, putamen, and caudate nucleus.
Cerebellum
Regulates equilibrium, body posture, and coordinated fine motor movements (necessary for rapid speech). Receives neural impulses from other brain centers and helps coordinate and regulate those impulses. Acts as a “modulator” of neuronal activity through its afferent and efferent circuits. Not a primary motor integration or initiation center. Lies below the cerebrum and behind the brainstem. Consists of two hemispheres. Damage to this structure results in ataxia or other communication disorders.
Afferent Fibers
Travel through the inferior and middle cerebellar peduncles. Mediate almost all sensorimotor information to the cerebellum. Superior, middle, and inferior peduncles communicate between this structure and the brainstem.
Efferent Fibers
Travel through the superior cerebellar peduncle. Transmit information from the cerebellum to the brainstem. From there, the information is transmitted to the thalamus, motor cortex, and spinal cord.
Cerebrum/Cerebral Cortex
Biggest and most important CNS structure for language, speech, and hearing. A complex structure of intricate neural connections that contains approximately 10 – 15 billion neurons and weighs about 3 lbs. Often referred to as gray matter. Surface appears wrinkled because it is folded to accommodate as much tissue as possible in a small space.
Gyrus
A ridge on the cortex on the cerebrum.
Sulcus
Shallow valley on the cerebrum.
Fissures
Deep valleys on the cerebrum. Boundaries between the broad divisions of the cerebrum.
Longitudinal Fissure
Fissure that courses along the middle of the brain from front to back, and divides the cerebrum into the left and right hemispheres.
Fissure of Rolando/Central Sulcus
A major fissure that runs laterally, downward, and forward, and arbitrarily divides the anterior from the posterior half of the brain.
Sylvian Fissure/Lateral Cerebral Fissure (Sulcus)
Fissure that starts at the inferior portion of the frontal lobe at the base of the brain and moves laterally and upward. Areas of the brain surrounding this fissure are especially critical in speech, language, and hearing.
Frontal Lobe
Lobe of the brain located on the anterior portion of the cerebrum in front of the central fissure and above the lateral fissure. Makes up approximately one third of the surface area of the cerebrum. Contains areas that are critical to the deliberate formation of plans and intentions that dictate a person’s conscious behaviors and areas that are crucial for speech production. These areas include the primary motor cortex, a supplementary motor cortex, and Broca’s area.
Primary Motor Cortex/Motor Strip
Cortex located on the precentral gyrus. This area controls voluntary movements of skeletal muscles on the opposite side of the body. All muscles of the body, including those for speech production, are connected to this structure through descending motor nerve cells.
Precentral Gyrus
A large ridge that lies anterior to the central sulcus.
Contralateral Motor Control
Principle which notes that each cerebral hemisphere controls the opposite side of the body.
Supplementary Motor Cortex
Cortex located in the frontal lobe that is believe to be involved in the motor planning of speech. Plays a secondary role in regulating muscle movements.
Broca’s Area
A motor speech center. Important for production of well-articulated fluent speech. Located in the third convolution of the left cerebral hemisphere. Anterior to the portion of the primary motor cortex that controls lip, tongue, jaw, and laryngeal movements. Damage to this area can cause motor speech problems.
Parietal Lobe
Lobe of the brain located on the upper sides of the cerebrum behind the frontal lobe and is the primary somatic sensory area. Integrates contralateral somesthetic sensations such as pressure, pain, temperature, and touch.
Postcentral Gyrus
Primary sensory area that integrates and controls somesthetic sensory impulses. Also called the sensory cortex/strip. Lies behind the central sulcus. In the parietal lobe.
Supramarginal Gyrus
Gyrus that lies superior to the lateral fissure in the inferior portion of the parietal lobe. Damage to this gyrus can cause conduction aphasia. In the parietal lobe.
Angular Gyrus
Gyrus that lies posterior to the supramarginal gyrus. Damage to this area can cause writing, reading, and naming difficulties and, in some cases, transcortical sensory aphasia.
Occipital Lobe
Lobe of the brain that is primarily concerned with vision. Contains the primary visual cortex. Located behind the parietal lobe at the lower posterior portion of the head, just above the cerebellum.
Temporal Lobe
Lobe of the brain that lies inferior to the frontal and parietal lobes and in front of the occipital lobe. Lowest one-third of the cerebrum. Contains two general areas that are critical to hearing and speech: primary auditory cortex and auditory association cortex.
Primary Auditory Cortex
Cortex located in the temporal lobe. Located on the superior temporal gyrus. Receives sound stimuli from the acoustic nerve bilaterally.
Auditory Association Area
Area of the brain located in the temporal lobe. Lies posterior to the primary auditory cortex. Synthesizes information from sound stimuli so that it can be recognized as whole units. Synthesizes speech in the dominant side of the brain and non-speech sounds in the nondominant side of the brain.
Heschl’s Gyri
A term used to reference the transverse convolutions that make up the primary auditory cortex and the auditory association cortex.
Wernicke’s Area
Area within the temporal lobe located in the posterior two-thirds of the superior temporal gyrus in the left hemisphere. Critical to the COMPREHENSION of spoken and written language. A lesion in this area will cause an aphasia where the patient produces fluent but meaningless speech and experiences significant language comprehension problems.
Arcuate Fsciculus
Connects Broca’s and Wernicke’s areas.
Pyramidal System
The direct motor activation pathway that is primarily responsible for facilitating voluntary muscle movements (speech). Composed of the corticobulbar and corticospinal tracts.
Tracts
Bundles of nerve fibers coursing through the CNS.
Corticospinal Tract
Tract of the pyramidal system that has nerve fibers that descend from the motor cortex of each hemisphere through the internal capsule.
Corticobulbar Tract
Tract of the pyramidal system that is critical to speech production. Fibers of this tract control all of the voluntary movements of the speech muscles (except the respiratory muscles).
Lower Motor Neurons
Motor neurons in the spinal cord and cranial nerves. Include nerve fibers that exit the neuraxis (spinal cord and brain) and communicate with the peripheral (cranial and spinal) nerves for innervation of muscles. Part of the PNS. Activity eventually results in muscular movements.
Upper Motor Neurons
Motor fibers within the CNS. All the descending motor fibers that course through the CNS. Include the pathways of both the pyramidal and extrapyramidal systems.
Extrapyramidal System
System important for speech production. Considered a more indirect activation system that interacts with various motor systems in the nervous system. Damage to this system creates motor disturbances and “involuntary movement disorders.”
Fasciculi
Long connecting fibers.
Intrahemispheric Fibers
Fibers that allow areas within each hemisphere to communicate with each other.
Interhemispheric Fibers
Fibers that permit communication between hemispheres and are composed mostly of myelinated axonal fibers (white matter). Includes projection, association, and commissural fibers.
Projection Fibers
Fibers that create connections between the cortex and subcortical structures like the cerebellum, basal ganglia, brainstem, and spinal cord. Some fibers transmit motor information to glands and muscles, while other fibers carry sensory information to the brain.
Internal Capsule
Contains the concentrated and compact projection fibers near the brainstem.
Corona Radiata
Transmits information to other portions of the brain. Formed as projection fibers move upward toward the upper regions of the brain and fan out.
Afferent Projection Fibers
Relay sensory information (such as smell) from the peripheral sense organs (e.g., nose) to the brain.
Efferent Projection Fibers
Projection fibers that come together in the internal capsule and pass through the thalamus and basal ganglia. Relay motor commands to glands and muscles.
Association Fibers
Connect areas with a hemisphere. Assist in maintaining communication between the structures in a hemisphere. Can be short or long.
Commissural Fibers
Fibers that are interhemispheric connectors. Run horizontally and connect the corresponding areas of the two hemispheres. Most important fiber of this type is the corpus callosum.
Corpus Callosum
Thick, broad band of myelinated fibers that connects the two hemispheres at their base. Most important commissural fiber system.
Disconnection Syndromes
Occur when damage to the corpus callosum disconnects the two hemispheres. Characterized by problems in naming, reading, movement, and other functions.
Cerebral Ventricles
A system of deep cavities deep within the brain. Filled with CSF.
Choroid Plexus
Produces CSF.
Cerebrospinal Fluid (CSF)
Fluid that circulates throughout the nervous system and nourishes the neural tissues, removes waste products, cushions the brain, and regulates intracranial pressure.
Lateral Ventricles
Two largest cerebral ventricles. Located immediately inferior to the corpus callosum. C-shapes. Course through the lobes of the cortex.
Third Ventricle
Cerebral ventricle located behind the lateral ventricles at the top of the brainstem. Looks like a broad disk. Connected with the lateral ventricles by the foramen of Munro.
Fourth Ventricle
Cerebral ventricle located between the cerebellum and the pons. Continuous with the central canal of the spinal cord below and the cerebral aqueduct above.
Cerebral Aqueduct
Connects the fourth and third cerebral ventricles.
Meninges
Layers of tissue that protect the brain.
Dura Mater
Thick, tough, outermost membrane whose one side adheres to the skull and whose other side adheres to the arachnoid. “Tough mother.”
Arachnoid
Semitransparent, thin, delicate, weblike, and vascular middle membrane of the meninges. CSF fills between this layer and the inferior layer. “Spider web.”
Pia Mater
Delicate, thin, transparent membrane that adheres to the brain surface and closely follows its gyri and sulci. Many blood vessels penetrate this layer of the meninges to enter the brain. “Tender mother.”
Aorta
Main artery of the heart. Carries blood from the left ventricle to all parts of the body except the lungs. Arch divides into four branches.
Vertebral Arteries
Left and right arteries that branch out from the two subclavian arteries that emerge from the aortic arch.
Carotid Arteries
Left and right arteries that enter the neck. Each branches out into an internal carotid artery and external carotid artery. These arteries enter the brain through the base of the skull and go through the dura mater and subarachnoid space.
External Carotid Artery
Artery that moves toward the face and branches into smaller arteries. Supplies blood to the muscles of the mouth, nose, forehead, and face.
Internal Carotid Artery
Artery that is a major supplier of blood to the brain. Branches into several smaller blood vessels that supply different parts of the brain, including the ACA and MCA.
Middle Cerebral Artery
Artery that is the biggest branch of the internal carotid artery. Supplies the lateral surface of the cortex, including the major regions of the frontal lobe. Supplies blood to major areas involved with motor and sensory functions and speech, language, and hearing functions. Supplies the motor cortex in the precentral gyrus, Broca’s area, primary auditory cortex, Wernicke’s area, supramarginal gyrus, angular gyrus, and the somatosensory cortex. Damage to this artery may result in strokes, aphasia, reading and writing deficits, contralateral hemiplegia, impaired sense of pain, temperature, touch, and position.
Anterior Cerebral Artery
Artery that primarily supplies the middle portion of the parietal and frontal lobes. Supplies blood to the corpus callosum and basal ganglia. Branches of this artery join with the PCA. Damage to this artery can cause cognitive deficits such as impaired judgment, concentration, and reasoning, and paralysis of the legs and feet.
Circle of Willis
Formed at the base of the brain where the two carotid and the two vertebral arteries join. Completed by the anterior and posterior communicating arteries. PCA, MCA, and ACA branch out from this structure. Provides a common blood supply to various cerebral branches. If an artery is blocked above the circle, brain damage will occur because the brain has no alternative source of blood. If an artery is blocked below the circle, brain damage may be minimal because alternate channels of blood flow may be maintained.
