Dysphagia and neural control of swallowing, digestive and respiratory systems Flashcards
What are signs of dysphagia?
reflux from esophagus or stomach; difficulty chewing food; coughing while swallowing food; struggle with starting a swallow; food sticking in the throat; hard to control food in the oral cavity;
Oropharyngeal Dysphagia consists of ________ and __________ .
penetration; aspiration
What is penetration?
foreign material enters the airway and makes contact to the true VFs
What is aspiration?
foreign material enters the airway and passes the true VFs; known as tracheal aspiration
Dysphagia is defined as _________ .
struggle to moving food from mouth to the stomach
What are causes of dysphagia?
malnutrition, dehydration, and AP (aspiration pneumonia)
What is dysphagia a symptom of?
COPD, HNC, developmental disability
What are classic signs of AP (aspiration pneumonia)?
cyanosis; hypotension; hypoxemia (can lead to death); gastric material in the oropharynx; wheezing; coughing; shortness of breath; pulmonary edema;
What are the four steps involved in neural control of swallowing?
afferent input (sensory information from vision, olfaction, and audition); medullary nuclei in the brainstem; efferent output (motor nuclei send messages to muscles involved in swallowing); descending cortical and subcortical inputs
Regarding afferent input in the neural control of swallowing, what steps are involved?
Cephalic control —> oral phase —- > initiation of pharyngeal swallow —- > modulation of pharyngeal swallow
Regarding the second phase of neural control of swallowing, the medullary nuclei are known as the __________ .
central pattern generator in the brainstem
The central pattern generator has two parts:
dorsal swallowing group (programming component) and ventral swallowing group (motor component)
What is pneumonitis? What causes it?
lung inflammation caused by exposure to chemicals, irritants, or allergens as well as a side effect of a medical procedure or a medication (i.e., iatrogenic)
What is pneumonia? What causes it?
lung infection caused by bacterial/viral pathogen from the oropharynx
What is dysphagia related aspiration pneumonia?
features of pneumonia; patient has dysphagia; infiltrates found in the gravity dependent parts of the lungs
What is non-dysphagia related aspiration pneumonia?
Features of pneumonia; no dysphagia symptoms; can conceivably be related to GER or vomit (i.e., emesis), community acquired pneumonia, hospital acquired pneumonia
What are classic signs of massive AP?
fever, leukocytosis (i.e., increasd white blood cell count, cough, sputum (combo of mucous and saliva) production, inspiratory crackles; infiltrates (e.g., pus, blood, protein), in lung on chest x-ray (white appearance on chest x-ray
How does foreign material interfere with gas exchange?
blocks small airways, reduces amount of surfactant which inflammes the lungs; consequently, atelectasis (i.e., collapse of alveoli) can occur, thereby increasing likelihood of pneumonia
Regarding the third phase of neural control of swallowing, efferent output refers to __________ .
cranial nerves (CN 5, 7, 8-12) and motor nuclei and cervical segments (C1-C3)
What motor nuclei are involved in efferent output (i.e., third phase of neural control of swallowing)?
trigeminal nucleus (pons), facial nucleus (pons), nucleus ambiguus (medulla), hypoglossal nucleus (medulla), spinal nucleus (C1-C3), dorsal motor nucleus of CN X
Modulation of swallowing depends on
type of material to be swallowed; properties of bolus to be swallowed; swallowing task
Regarding the fourth phase of neural control of swallowing, the cortical regions involved in swallowing are
primary sensorimotor cortex, premotor cortex, anterior insula (also related to emotional processing)
Regarding the fourth phase of neural control of swallowing, the subcortical circuits involved are
basal ganglia, internal capsule, hypothalamus, midbrain ventral tegmental field (facilitates reflexive swallow)
Describe the lateralization of swallowing.
It is a tendency for one hemisphere to be greatly involved in swallowing. Swallowing is controlled mainly by the left hemisphere. However, the right hemisphere is involved too. People who have right hemisphere dominant showed stronger lateralization than people who were left hemisphere dominant; thus, such individuals have the RT hemisphere be more responsible for the RT. Left hemisphere dominant have bilateral lateralization. Swallowing should be thought of as involving both hemispheres (i.e., bilateral)
What regions of the brain are not important in activating the muscles involved in the pharyngeal and esophageal stages of swallowing?
cortical and subcortical regions
What region of the brain plays a role in the initiation of swallowing and level of neuromuscular activity?
cerebral cortex
What are the functions of the digestive system?
Removes waste; breaks down ingested material and absorbs nutrients from such material
What are the organs of the digestive system?
Large intenstine, anus, mouth, esophagus, small intestine, and stomach
What are the accesory organs of the digestive system?
Pancrease, gallbladder, salivary glands, liver
Describe the physiology of the digestive system.
food is ingested and them propulsed down the esophagus. Then, it is broken down mechanically (via chewing) and chemically (nutrients from the chewed up food are absotred). Then, food that is not needed is defecated as waste.
What are the factors related to aspiration tolerance?
mobility, nutritional status, pulmonary status, status of immune system, age, nature of aspirate, prior history of pneumonia, level of consciousness
Describe airway clearance in the proximal LRT (lower respiratory tract).
Airway clearance is mechanical, which means that the structures of proximal LRT are involved. Coughing and mucociliary action are the two ways foreign particles are cleared from the proximal LRT.
What is coughing?
a reflex that expels foreign material in the proximal LRT. To occur, the trachealis muscle of the trachea narrows and subglottal pressure rises.
What is mucociliary action?
one of two respiratory defense mechanisms in the proximal LRT. It occurs when the movement of cilia in the trachea propels mucus and other foreign particles up towards major airways
Describe airway clearance in the distal LRT
In the distal LRT, alveolar macrophages remove foreign particles and lymphatics remove liquids. The alveolar macrophages eat the foreign material (i.e., perform phagocytosis) and then kill them. Lymphatics (lymphatic vessels and lymph nodes) drain liquids from the distal LRT which may contain foreign material
What is the proximal LRT?
The trachea, lungs, and larynx
What is the distal LRT?
Bronchi, bronchioles, and alveoli
