Anatomy of Speech and Hearing Mechanisms

cystology

cells

myology

muscles

histology

cells and function

arthrology

joints

domains of pre-clinical speech science

• neural

• muscular

• structural

• aeromechanical

• acoustic

• perceptual

speech subsystems

• velopharyngeal nasal

• pharyngeal-oral

• laryngeal

• respiratory

hearing subsytems

outer ear

middle ear

inner ear and auditory nerve

central auditory pathways

hearing levels of subsystems

acoustic

aeromechanical

structual

muscular

mechanosensory

neural

muscular tissue

striated, attached to muscle/bone

• smooth -lining of walls of vessels and organs

• skeletal - attached to bones, voluntary muscle that enables movement and pressure

• cardiac - heart muscle that contracts rhythmically to pump blood

connective tissue

• ligament - connects bone to bone and helps stabilize joints

• cartilage - rubbery tissue that cushions joints

• fibrous tissue - tendon - attaches muscle to bone

epitheleal tissue

skin made up of this, lines internal organs, made up of layers that protect substances

• stratified squamous - layered on skin, esophagus, and lining of mouth to protect

• pseudo-stratified columnar ciliated - single layer in respiratory tract (trachea and bronchi) for secretion and movement mucousiu

somotopic organization

spatial representation of the body within the nervous system where each part of the body is mapped to a specific part of the brain (primarily motor and somatosensory cortex)

CNS

• cerebral hemispheres

• cerebellum

• brain stem

• spinal cord

PNS

• nerves from brainstem and spinal cord

• ganglia - receive sensory signals from sensory receptors in the body and deliver sensory info to CNS

white matter

myelinated axons, connects areas of gray matter/ cortical regions

gray matter

aka subcortical nuclei - clusters of neuron cell bodies in the central cortex of the brain, processes and interprets information

tracts vs nerves

bundles of axons in the CNS vs bundles of axons in the PNS

effrent vs affrent

brain to muscle signals vs muscle to brain signals

cerebral hemisphere

part of CNS

• longitudinal fissure

• cortex - responsible for higher level functioning

• gyri - hills

• sucli- valleys

lateralized and specialized function

functions that are generally restricted to one hemisphere of the brain (speech, language, emotions) vs regions of the brain which serve distinct functions like frontal lobe for exec func

Frontal lobe

• broca’s area

• planning/ organization

• speech - nouns and syntax

• primary motor cortex - PMC neurons —> brain stem and spinal cord neurons —> muscles (route of direct nervous system control)

temporal lobe

• primary auditory cortex- first processor of auditory info

• wernickes area

insula (5th lobe)

• part of limic system

• anterior insula involved in speech production and speech motor control

• control of breathing and swallowing

corpus callosum

c shaped communicator btwn hemispheres

corticospinal tracts

from motor cell bodies in dorsal cortex (unconcious visuomotor actions like reaching and grasping) to motor neurons in brainstem (specifically pons and medulla)

• mostly contralateral innervation

corticobulbar tracts

from motor cell bodies in lateral cortex to first synapse in motor cells of ventral spinal cord (sends motor neurons to skeletal muscles (voluntary movement)

subcortical nuclei

cell clusters deep in cerebral hemispheres but below brainstem

• includes basal ganglia, thalamus, hypothalamus, amygdala, septal nuclei

basal ganglia

responsible for coordination, refining movements including speech rhythm/rate, and responsible for dysfluencies

• regulated by cortico-striatal-cortico loop

Cortico-striatal cortico loop

Cortex sends signals to striatum (caudete and putanem) which signal to other parts to thalamus and back to cortex to facilitate or inhibit movement

• direct pathway - faciliating signals to thalamus

• indirect pathway - inhibitiing signal (competing actions) to thalamus

thalamus

egg shaped relay station of senses to the brain (except smell)

cerebellum

primary role in movement coordination and balance

brainstem

relays info from cranial nerves

meninges

protective layer around brain

• dura matter - toughest layer close to skull that protects all tissue in SNS and cerebral fluid

• arachnoid matter - circulatory system within where cerebral fluid circulates just below

• pia matter - very thin, hugs gyri and sulci of brain

ventricles

three ventricles connected to brainstem that cerebral fluid circulates around

• third and 4th ventricle manufacture cerebrospinal fluid

cerebro spinal fluid

protects brain and provides shock absorbing environment for CNS

• circulates thru ventricles and subarachnoid space

glial cells

nervous system cells that provide structural support for cells in axtracellular environment

• wrap around axons and form fatty layers so nerve impulses more fluid passing thru

ependymal cells

line ventrical cells and help circulate cerbrospinal fluid

synaptic cleft

gap btwn pre-synaptic neuron and postsynaptic cell where neurotransmitters released to transmit from one cell to another

anterior vs posterior circulation

• anterior - blood supplied from internal carotid arteries via aortic arch to frontal, parietal, and temporal lobes

• posterior - supplied by basilar artery to brainstem, cerebellum, and occipital lobe

circle of willis

arteries forming circle at base of brain that provides blood to major areas of speech and language comprehension

Cotricospinal tracts

tracts in CNS that originate in cortex that go to neurons in spinal cord and are distributed to the rest of the body (top-down)

• 80 percent are contraleteral

Corticobulbar tracts

tracts in CNS from cortex of brain to brain stem motor neurons - goes thru midbrain, pons, and medulla

• most tracts ipsilateral

frontal lobe

important for executive function - language organization including personality and pragmatic elements like knowing when to stop talking (inhibiiton too)

purpose of respiratory system

oxygenates the body and does ventilation by moving air in and out

Breathing apparatus

made up of pulmonary apparatus and chest wall

• formed by skeletal bone and cartilage

• 12 pairs ribs - last 2 floating

• attached to cartilage which is attached to sternum and breastbone

Pectoral girdle

part of respiratory system made of clavicles and scapulae

Pelvic girdle

part of respiratory system made up of coxigeal vertebrae and coxal hip bones

vertebral collumn parts

starts smaller and grows larger

• cervical

• thorastic

• lumbar

• sacral

• coccygeal

pulmonary apparatus

made up of lungs and airways, provides oxygen to the body

lungs

• 5 lobes, 3 left, 2 right

• cone shaped and made up of resilient elastic fibers

• visceral pleura: thin airtight membrane on outside surface

• pleura membrane: inner chest wall membrane

• pleural linkage: fluid between two membranes that creates less friction so lungs can expand and contract

lower airways

• trachea - c-shaped cartilages that run down from back to torso

• bronchi - branches inside lobes lungs that get smaller and smaller

• main stem bronchi - to right and left lungs

• lobar bronchi - bronchi of each lobe

• 20 generations of divisions of bronchi that end with alveoli

• alveoli - sacs at ends of bronchi that expand and contract w lungs

chest wall

rib cage wall, abdominal wall, diaphragm, abdominal content

diaphragm

forms floor of thorax btwn thorax and abdomen

rib cage wall

• Forms most of the thorax

• Surrounds the lungs (except at the bottom)

• Consists of thoracic vertebrae, ribs, costal cartilages, sternum, and pectoral girdle

abdominal wall

Consists of 15 vertebrae (lumbar, sacral,

coccygeal), pelvic girdle, muscles, and

connective tissue (abdominal aponeurosis and

lumbodorsal fascia)

abdominal content

• Includes stomach, intestines, etc.

• Essentially the density of water

• Suspended from undersurface of diaphragm by suction force

pulmonary apparatus

• connected to chest wall by "pleural linkage"

• resting size of the pulmonary apparatus is larger when linked than unlinked

• resting size of the chest wall is smaller when linked than unlinked

forces of breathing apparatus - active vs passive

passive - forces that are always present in body (automatic) such as natural recoil of muscles, cartilage, ligaments, lung tissue and surface tension of alveoli plus gravity

active - voluntary and includes rib cage wall muscles, diaphragm muscle and abdominal wall muscle

chemical signal

impulse between two neurons or a neuron and a muscle

Where do upper motor neuron cell bodies cluster in the central nervous system?

primary motor cortex

What do you call the bundles of upper motor neuron axons in the central nervous system

corticobulbar and corticospinal tracts

Where do lower motor neuron cell bodies cluster in the peripheral nervous system

brainstem and spinal cord

What do you call the bundles of lower motor neuron axons in the peripheral nervous system?

cranial nerves and spinal nerves

Speech/ hearing functions Trigeminal (V)

Mixed: sensory to face, tongue, teeth.

Motor: muscles of jaw movement plus myloyoid muscle, tensor tympani muscle, tensor veli palatini muscle

Speech/ hearing functions Facial (VI)

Mixed: sensory to parts of external ear, taste for anterior 2/3rd of tongue.

Motor to muscles of facial expression plus stapedius muscle; control of salivatory glands

Speech/ hearing functions Vestibulocochlear (VIII)

sensory: hearing, balance, coordination of head with body motion

Speech/ hearing functions Glossopharyngeal (IX)

Mixed: sensory for parts of external ear, eardrum, upper part of pharynx, taste for posterior 1/3rd of tongue, detection of blood gasses and pressure

Motor: stylopharyngeus muscle, control of salivatory glands in pharynx

Speech/ hearing functions Vagus (X)

Mixed: sensory for pharynx, larynx, meninges, heart, gut.

Motor: muscles of pharynx, larynx, smooth muscles of heart and gut

Speech/ hearing functions Accessory (XI)

Motor: sternocleidomastoid and trapezius muscles

Speech/ hearing functions hypoglossal

Motor: most intrinsic and extrinsic muscles of tongue