Chapter 1: Anatomy + Physiology of Communication and Swallowing Flashcards
Ciliated epithelium
single cell thickness, lines the airway from the bronchi through the nasal cavities, paranasal sinuses, and false vocal folds
Ciliated pseudostratified columnar epithelium
single cell thickness, lines the trachea and the upper respiratory tract
Squamos epithethelium
lines alveoli in the lungs and interior surface (or endothelium) of lymph and blood vessels
Nonkeratinzed stratified squamos epithelium (mucosa)
multiple cell thickness, lines the mouth, pharynx, esophagus, true vocal folds.
Keratinzed stratified squamos epithelium
multiple cell thickness, forms the skin, and has outer layer of dead cells which provides a waterproof barrier
Hyaline cartilage
a type of connective tissue, helps maintain a patent airway by forming rings in the bronchi, partial rings in the trachea, and most cartilages of the larynx
Elastic cartilage
contains many yellow elastic fibers and collagen (type 2) and elastin. It is found in the epiglottis and pinnae of the ears
Multipolar neurons
have multiple dendrites and a single axon extending a relatively far distance from the soma. These are found throughout the CNS and include motor neurons
Bipolar neurons
have 2 processes extending from the soma, with one serving as an axon and one as a dendrite. Found in the PNS sensory pathways for special senses of the head (smell, taste, vision, hearing)
Unipolar neurons
single fused process; the distal part is the dendrite and the rest is the axon. These are found in PNS sensory pathways for senses represented throughout the body, including fine touch, vibration, proprioception, pressure, pain, and temperature
Which glial cells form the myelin sheath in the PNS and CNS
PNS - Schwann cells
CNS - Oligodendrocytes
At rest, neurons maintain a resting potential of what on the inside of the cell
-65 mV - this negative potential keeps the neurons prepared to fire
What 2 types of Na+ channels are selectively open during neural signaling
Chemically gated sodium channels (located on the dendrites and soma) and Voltage-gated sodium channels (located on axon membrane)
It takes ____mV of depolarization to open voltage gated sodium channels
15
Differences between CNS and PNS neurons
CNS - poor regenerative capabilities and limited in what they can receive from circulating blood due to the blood brain barrier
2 divisions of the PNS
Somatic and autonomic
Somatic NS
Supports sensations and motor functions of the body that are consciously perceived and volitionally controlled (allows one to be aware of the external environment and act on it)
Autonomic NS
Functions mostly below consciousness or control, regulating visceral functions. It detects and acts on the body’s internal environment
2 divisions of the autonomic NS
Sympathetic and parasympathetic
Sympathetic NS
Activated in times of perceived threat, fight or flight response, inhibits nonessential body functions
Parasympathetic NS
Helps maintain homeostasis, rest and digest.
Sensory axons in the cranial nerves are
Unipolar or bipolar neurons with their somas clustered in peripheral ganglia at some point along the nerve
Motor axons in the cranial nerves are
Multipolar neurons clustered in the brainstem or in the upper cervical spinal cord
Sensory neurons of the spinal cord
Enter the spinal cord through the dorsal (or posterior) roots with their somas clustered in the dorsal root ganglia
Motor neurons of the spinal cord
Leave the spinal cord through the ventral (or anterior) roots with their somas clustered in the ventral root ganglia
Meninges of the CNS
Pia, arachnoid, dura (PAD) deep to superficial
CFS is created in the
Ventricular system by a sponge-like tissue called the choroid plexus
Association fibers
Connect areas within the same cerebral hemisphere
Commissural fibers
Connect the 2 hemispheres of the brain
Medulla oblongata functions?
Guides several autonomic functions such as respiration, cardiac rate, vascular contraction/dilation, and integration of sensory information for reflex motor responses such as coughing, vomiting, and swallowing
Which motor nuclei are in the medulla?
Nucleus ambiguus (CN IX and X) and hypoglossal motor nucleus (CN XII)
Which motor nuclei are in the pons?
Trigeminal (V) and facial (VII)
Cell rich region that surrounds the cerebral aqueduct in the Midbrain
Periaqueductal gray (PAG). This receives and processes pain information and plays a critical role in coordinating phonatory, articulatory, and respiratory movements for sound production in all vocalizing animals. Lesions here can cause mutism in humans
Reticular formation functions?
Coordinate motor functions of the body and of the head. Also important for sleep/wake cycles. Also directs our attention
Premotor cortex functions?
Involved in performance of skilled movements such as those necessary for speech and regulation of the primary motor cortex
Primary motor cortex
Motor homunculus
Primary somatosensory cortex
Sensory homunculus
Limbic cortex/lobe functions?
Important for memory, emotion, and drive-related behavior (responsible for primitive behaviors)
Parts of the basal ganglia
Striatum, substantia nigra, globus pallidus, subthalamic nucleus
Striatum is composed of the
Caudate and putamen divided by the internal capsule
2 parts of the substantia nigra
Pars compacta and pars reticulata.
Substantia nigra pars compacta functions?
Contains dopamine-producing cells that send projections to the striatum
Substantia nigra pars reticulata functions?
contains cells that produce the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) that projects onto motor regions of the thalamus, which in turn project to the motor cortex
Thalamus functions?
Almost all sensory information that we consciously perceive is relayed through and processed by this structure. Motor pathways also travel through the thalamus.
Hypothalamus functions?
Communicates with the pituitary gland to maintain metabolic and hormonal homeostasis of the body (body temp, thirst, hunger, fatigue, circadian rhythms)
What is the pyramidal system?
Direct motor pathway. Comprises axons that carry efferent signals that descend from UMN in the cerebrum to LMN in the brainstem/spinal cord. Function is to control skilled, voluntary movements of our extremities.
What are the 2 direct motor pathways?
Corticospinal tract and corticobulbar tract
Corticospinal tract
Extends from the primary and premotor cortex, supplementary motor areas, and parietal lobe through the internal capsule into the midbrain, through the pons and medulla. Then when it reaches the transition point from the brainstem to the spinal cord, 85% of the fibers cross over in the pyramidal decussation and control the opposite side of the body.
2 parts of the corticospinal tract
Lateral corticospinal tract - these are the fibers that decussate and go on to synapse with LMN in the spinal cord (ventral horn).
Anterior corticospinal tract - these are the fibers that do not decussate. They synapse contralaterally or bilaterally in the spinal cord ventral horn and are involved in control of the midline (trunk) musculature
Corticobulbar tract
Extends from a lateral portion of the motor cortex near the sylvian fissure through the internal capsule and through the ventral portion of the midbrain. Within the pons and medulla the axons project contralaterally or bilaterally onto CN motor nuclei. Most are bilaterally innervated except for the lower face (CN VII) and tongue (CN XII). Axons from the motor nuclei (LMN) then exit the brainstem ipsilaterally.
What is the extrapyramidal system?
The indirect motor pathways. They are involved in reflexes and coordination of multiple muscle groups as well as in the modulation and regulation of posture, balance, tone, and some voluntary movements.
What are the 4 extrapyramidal tracts?
Rubrospinal, reticulospinal, tectospinal, and vestibulospinal
Cerebellar control circuits
Integrates afferent and efferent signals from the brain and spinal cord. The cerebellum compares motor intent with actual motor execution.
Basal ganglia control circuits
Circuits contribute inhibitory or facilitatory input to the cortex. Refines motor movements, increasing precision and form while reducing extraneous activity.
2 major ascending somatosensory pathways
Anterolateral pathway and posterior column-medial lemniscal system
Anterolateral system
Conveys the sensations of pain and temperature, as well as crude or non-localizable touch. Comprises the spinothalamic tract, the spinoreticular tract, and the spinotectal tract
Posterior column-medial lemniscal system
Carries information about pressure, vibration and fine touch
Artery
Carries oxygen and nutrient-rich blood to the body. Eventually branch into smaller and smaller vessels (arterioles) and then to vessel size called capillaries.
Veins
Carry deoxygenated, waste-laden blood from the body back to the heart and lungs. These are thin-walled and lower in blood pressure than arteries so therefore are not as prone to rupture.
Anterior blood supply to the brain originates from
Left and right carotid arteries
Posterior blood supply to the brain originates from
Left and right subclavian arteries
2 branches of the carotid artery
Internal and external
Internal carotid artery splits into
Anterior cerebral arteries (ACA) and Middle cerebral arteries (MCA)
ACA supplies blood to
Medial surfaces of cortex from frontal to parietal regions and regions deep to lobes (Basal ganglia, etc.)
MCA supplies blood to
Lateral frontal lobe, lateral temporal lobes, portions of lateral parietal lobe, regions to deep lobes (basal ganglia, etc.)
External carotid artery supplies blood to
The head and dura, not the brain
Left subclavian artery stems from the
Arch of the aorta
Right subclavian artery stems from the
Brachiocephalic trunk
Subclavian arteries give rise to
The vertebral arteries
Left and right vertebral arteries send off branches that supply
The anterior spinal cord and posterior cerebellum
Left and right vertebral arteries after they have traveled up the cervical vertebrae and entered the skull through the foramen magnum join together to form
The basilar artery
The basilar artery sends off branches that supply
The pons, medulla, and cerebellum
At the level of the midbrain, the basilar artery splits into
Left and right posterior cerebral arteries (PCA)
Posterior cerebral arteries supply blood to
Occipital lobes, inferior and medial temporal cortices, and regions deep to lobes (thalamus, etc.)
Right lung has __ lobes and left lung has ___ lobes
3 and 2
Aspiration is more common in the ___ lung because of the angle at which the bronchi enter the lungs
Right lung
The internal thoracic wall and lungs are coated in connective tissue called
Pleural linings
What is pleural linkage
Surface tension between the wet pleural linings draw the lungs to the rib cage and diaphragm
What are the 4 major muscle groups involved in respiration
The diaphragm, abdominals, external and internal intercostals
What are 2 accessory muscles that are important in inspiration
Sternocleidomastoid and scalene
Which brain structure is critical in passive breathing
The brainstem (in particular the medulla)
3 areas of the brainstem that monitor blood gas levels, respiratory system pressures, and respiratory anatomy position/contractions
Chemoreceptors in the medulla monitor CO2, O2, and pH levels of the blood. Mechanoreceptors in the lung, airway and thoracic wall respond to changes in lung volume, changes in force exerted by inspiratory and expiratory muscles, and the presence of aggravating substances such as dust, smoke, or cold air. Proprioceptors in respiratory system muscles and associated joints inform brainstem respiratory centers about body position and muscle movements.
Inspiration during quiet breathing
Medulla sends signals to contract the diaphragm. Contraction lowers/flattens the diaphragm, vertically enlarging the thoracic cavity and thereby expanding the lungs. Expansion of the lungs increases volume and generates negative pressure, which draws air inward. Medulla then sends signals to the external intercostals to contract. Contraction causes rib cage elevation and horizontal expansion, further distending the lungs. Contraction contributes to negative lung pressure that forces inhalation. Air rushes into the lungs until the pressures inside and outside of the lungs are equal.
Expiration during quiet breathing
The lungs, chest wall, and rib cage return to normal position due to elastic recoil of the lungs and rib cage and gravitational pull on the rib cage. The diaphragm returns to its resting position. This compresses the lungs and causes alveolar pressure to rise. Air is passively pushed out of the lungs until relaxation volume is reached.
Differences in inspiration during speech breathing as opposed to quiet breathing
More air inhaled and faster
Accounts for 10% of breathing cycle
Differences in expiration during speech breathing as opposed to quiet breathing
Larger volume of air exhaled
Accounts for 90% of the breathing cycle
Not a passive process, must be actively controlled by the valving of air by the glottis and contraction of muscles of inspiration to counteract gravitational pull and tissue recoil forces
Tidal volume
Average volume of air exchanged in a cycle of passive breathing. Represents about 10% of a persons vital capacity
Inspiratory reserve volume
The maximal volume of air that can be inspired above the level of tidal inspiration
Expiratory reserve volume
The maximal volume of air that can be expired below relaxation volume
Residual volume
The volume of air that remains in the lungs after a maximum exhalation
Vital capacity
Volume of air exchanged between a maximum inspiration and a maximum expiration (IRV + TV + ERV)
Functional residual capacity
Volume of air in the lungs at the end of the expiratory phase of tidal breathing (ERV + RV)
The superior cornu of the thyroid cartilage attaches to the hyoid via what ligament
Hyothyroid ligament
The arytenoids sit and articulate on the
Posterior superior edge of the cricoid cartilage
What 3 muscles attach to the muscular process of the arytenoid cartilages
Posterior cricoarytenoid muscle, lateral cricoarytenoid muscle, and thyroarytenoid muscle
Contraction of the muscles of the what invert the epiglottis?
Aryepiglottic folds
The primary function of the thyroarytenoid muscles and cricothyroid muscles is what?
To control vocal fold length and tension
What are the 6 intrinsic muscles of the larynx?
Vocalis muscle, cricothyroids, transverse and oblique interarytenoids, thyroarytenoids, lateral cricoarytenoids, posterior cricoarytenoids
All intrinsic muscles are innervated by ____ except for cricothyroids
Recurrent laryngeal nerve (CN X), cricothyroids = SLN
What is the action of the thyroarytenoid muscles?
Contraction draws the arytenoid cartilages forward and shortens and tenses the body of the vocal folds
What are the 2 divisions of the thyroarytenoid muscle?
Thryomuscularis (lateral) and thyrovocalis (medial)
2 divisions of the cricothyroid muscle?
Pars rectus (medial division) and pars oblique (lateral division)
What is the action of the contraction of the cricothyroid muscles?
Rocks the thyroid cartilage forward, stretching the vocal folds (raising pitch)
What 2 muscles adduct the vocal folds?
Lateral cricoarytenoid muscles and transverse and oblique interarytenoid muscles
What muscle abducts the vocal folds?
Posterior cricoarytenoid muscles
What are the 4 suprahyoid muscles?
Mylohyoid, geniohyoid, stylohyoid, and digastric belly
Function of the suprahyoid muscles?
Raise hyoid, pull larynx upward, forward, or backward, tensing the vocal folds and contributing to increased pitch, and contribute to opening of the upper esophageal sphincter
