lab 7 - respiratory air flow and volume

four steps of respiration

pulmonary ventilation

external respiration

transport of respiratory gases

internal respiration

pulmonary ventilation

movement of air into (inspiration) and out of (expiration) the lungs so that the gases in the lung are constantly refreshed with infusions of new air and effusions of old air

external respiration

carbon dioxide diffuses to the lungs from the blood and oxygen diffuses to the blood from the lungs

transport of respiratory gases

accomplished using the blood of the cardiovascular system

internal respiration

occurs as oxygen diffuses from blood to the cells of the body and carbon dioxide diffuses from the cells of the body to the blood

functions of the nose

warms and moistens entering air

provides resonating chamber for vocalizations

cleans and filters entering air

houses the olfactory receptors

olfactory mucosa epithelium

small portion of superior nasal cavity lined with this

contains receptors for smell

pseudostratified ciliated columnar epithelium

rest of nasal cavity is lined with this

contains goblet cells and seromucous nasal glands

what are the seromucous nasal glands composed of

cells that secrete mucous (traps bacteria, dust, and debris)

cells that secrete water (humidifies air), enzyme rich (antibacterial lysozyme) fluid

what do respiratory mucosa epithelial cells secrete

antibiotic defensins to assist in killing microbial invaders

sneeze reflex

triggered when irritants (dust, pollen, etc.) contact the rich supply of sensory nerve endings in the nasal cavity

sneeze forces these irritants out to protect the body from them

nasal conchae

increases surface area, helps create turbulence which deflects non-gaseous particles onto the mucous coatings

inspired air warmed, cools conchae so on expiration, moisture is precipitated out and heat is exchanged

paranasal sinuses

located in frontal, sphenoid, maxillary, and ethmoid bones

lighten the skull, but are prone to inflammation

results of inflamed nasal mucosa

excessive mucus production

congestion

postnasal drip

swallowing

soft palate and uvula move superiorly to block nasopharynx

epiglottis flaps over larynx to keep food our of nasal cavity and lungs

cilia propel mucus toward stomach

pharyngeal tonsil

adenoid

contains lymphatic tissue that traps and destroys pathogens

painful when infected and swollen

pharyngotympanic tubes

connect the middle ear to the nasopharynx

allows for air in middle ear to match atmospheric pressure

oropharynx and laryngopharynx

both receive food and air

have more protective stratified squamous epithelium

respiratory zone

site of external respiration (where gas is exchanged)

made up of the microscopic alveoli, alveolar ducts, and respiratory bronchioles

conducting zone

consists of all the tubes transporting air from the nose to the respiratory bronchioles

air humidified, warmed, and filtered/cleansed

larynx

houses vocal folds for voice production

laryngeal prominence

of thyroid cartilage

adam’s apple

more prominent in males then females as it is stimulated by androgens during male puberty to grow larger

arytenoid cartilage

anchor the vocal chords

glottis

collective name for the vocal folds

laryngitis

inflammation of vocal folds, causes swelling and incorrect vibration

valsalva maneuver

abdominal muscles contract, glottis closes, increase in intra-abdominal pressure helps to empty rectum

boyle’s law

at a constant temperature, the pressure of a gas varied INVERSELY with its volume

thoracic pressure changes upon inhalation and exhalation

decreases on inhalation

increases on exhalation

venous return on inhalation and exhalation

increases on inhalation

decreases on exhalation

vagal tone on inhalation and exhalation

decreases on inhalation

increases on exhalation

heart rate on inhalation and exhalation

increases on inhalation

decreases on exhalation

trachea

composed of mucosa (pseudostrat ciliated columnar) with goblet cells, submucosa (seromucus glands), and adventitia (outermost connective tissue sheath)

elasticity allows movement during breathing

cartilage rings allows esophagus to expand during swallowing and not obstruct airway

trachealis muscle

between esophagus and trachea

contraction aids in rapid movement of air and mucus out of lungs and trachea during coughing

alveolar sac

cluster of alveoli coming off an alveolar duct

squamous epithelial cells make up walls

alveoli

densely covered with pulmonary capillaries

ventilation perfusion coupling

the amount of gas reaching the alveoli and the blood flow in the pulmonary capillaries

must be a close match between two parameters so gas exchange is done most efficiently

pulmonary surfactant

decreases surface tension in alveoli

elastic fibers

surround the entire bronchial tree, including the alveoli

pleural fluid

between two pleural membranes

allows lungs to easily move as we breathe

lubricant

pleurisy

inflammation of the pleura

seen in pneumonia

pneumonia

inflammation primarily of the alveoli in lungs

cardiac notch

seen in the left lung to accommodate the heart

tertiary bronchi

serves each bronchopulmonary segment along with an independent artery and vein

lung compliance

stretchiness of lungs

the more a lung expands, the greater its compliance and the easier it is to make the lung expand

pressure volume relationship of pulmonary circuit

low pressure, high volume

renin angiotensin aldosterone pathway

helps regulate blood pressure

angiotensin converting enzyme in the lungs catalyzes the conversion of angiotensin I to angiotensin II

intrapulmonary pressure

pressure in the alveoli

changes as we breathe to move gases between lungs and blood and between lungs and atmosphere

intrapleural pressure

pressure in the pleural space

always slightly less than the intrapulmonary pressure

why is it important that the intrapleural pressure is LESS THAN the intrapulmonary pressure

difference helps keep the lungs from collapsing and keeps the bronchial tree open

pressure difference generated and maintained because pleural fluid is constantly being pumped out of the pleural cavity

transpulmonary pressure

the difference between the intrapulmonary and intrapleural pressures

atelectasis

collapsed lung

resistance

gives rise to a small pressure difference proportional to flow rate

tidal volume (TV)

amount of air expelled with each normal resting breath

breathing frequency in normal ventilation

15 respiratory cycles per minute

expired minute volume

the product of frequency and tidal volume

the amount of air exhaled in one minute of breathing

residual volume (RV)

the volume of air remaining in the lungs after a full expiration

cannot be measured via spirometry as volunteer is unable to exhale any further, that volume remains in the lungs

prevents lung collapse and keeps alveoli open

forced vital capacity (FVC)

obtained by inspiring as deeply and rapidly as possible and then expiring as deeply and rapidly as possible

forced expiratory volume (FEV1)

the volume of air expired during the first second of the expiration when performing the forced vital capacity

often represented in a percentage of the forced vital capacity (FEV1/FVC)

dalton’s law of partial pressure

the total pressure exerted by a mixture of gases will equal the sum of the partial pressures exerted independently by each of the gases in the mixture

henry’s law

states that when a gas is in contact with a liquid, the gas will dissolve into liquid in proportion to its partial pressure

the larger the concentration of this independent gas in the mixture of gases in the gas phase, the greater and more rapidly that independent gas will go into solution in the liquid

hyperbaric oxygen chambers

contain oxygen at partial pressures, higher than what we are normally exposed to in the atmosphere and can thus be used to drive oxygen into the blood of patients deficient in oxygen such as with carbon monoxide poisoning

inspiratory reserve volume (IRV)

amount of air that can be forcefully inhaled after a normal tidal inspiration

expiratory reserve volume (ERV)

amount of air that can be forcefully exhaled after a normal tidal expiration

total lung capacity (TLC)

maximum amount of air contained in the lungs after a maximum inspiration

inspiratory capacity

maximum amount of air that can be inspired after a normal tidal expiration

expiratory capacity

maximum amount of air that can be expired after a normal tidal inspiration

functional (forced) residual capacity (FRC)

volume of air remaining in the lungs after a normal tidal expression

hemoglobin

made up of four iron containing heme groups, each bound to a polypeptide chain subunit

oxyhemoglobin form

when each hemoglobin can carry four molecules of oxygen

deoxyhemoglobin

reduced to hemoglobin free of oxygen

affinity

the change in how easily oxygen binds to the hemoglobin

bohr effect

the increasing of partial pressures of carbon dioxide weakening the hemoglobin-oxygen bond

haldane effect

the less hemoglobin is saturated with oxygen the more readily it binds to carbon dioxide and can bind hydrogen ions to buffer carbon dioxide transport as bicarbonate

hypoxia

inadequate oxygen delivery to the body tissues and is classified based on the cause

anemic hypoxia

poor oxygen delivery due to erythrocytes that contain too little or abnormal hemoglobin or from too few erythrocytes

ischemic hypoxia

results from blocked or impaired blood circulation

histotoxic hypoxia

results when adequate oxygen is delivered but the body cells are unable to use it such as is the case when metabolic poisons (cyanides) are administered

hypoxemic hypoxid

when the partial pressure of dissolved oxygen in arteriole blood is low and is commonly caused by disordered ventilation-perfusion coupling, pathological pulmonary ventilation impairment, and breathing air deficient oxygen

carbon monoxide poisoning

form of hypoxemic hypoxia

caused by breathing smoke from fire or inhaling fumes of combustion

carbon monoxide has an astronomically higher affinity for hemoglobin than oxygen does and outcompetes oxygen for binding sites

ventral and dorsal respiratory group

set the rhythm

both medullary respiratory centers of the medulla oblongata

ventral respiratory group

rhythm generating center and integration center for breathing

eupnea

clinical term for a normal breathing rate

about 15 breaths per minute

dorsal respiratory group

integration center for signals from peripheral stretch receptors and chemoreceptors

responds to signaling from ventral respiratory group

pontine respiratory center

modifies and fine-tunes breathing rhythms and specifically smooths the alternating transitions between inspiration and expiration and vice versa

hypercapnia

clinical term for high carbon dioxide levels in the blood

hyperpnea

increase in breathing rate and depth based on metabolic need (a normal increase)

hypocapnia

low blood carbon dioxide levels

what does hyperventilation cause

hypocapnia and alkalosis

hypocapnia and alkalosis

cause cerebral blood vessels to constrict, decreasing perfusion and increasing ischemia to the brain resulting in dizziness or fainting

apnea

clinical term for breathing cessation

spirometry

the method of choice for a fast and reliable screening of patients suspected of having an obstructive pulmonary disease

chronic obstructive pulmonary disease (COPD)

emphysema and chronic bronchitis

involve an irreversible decrease in the ability to move air out of the lungs (and thus decrease RV)

dyspnea

the clinical term for difficult or labored breathing and is a symptom of COPD

hypoventilation

clinical term for inadequate ventilation to meet metabolic needs thus resulting in retained carbon dioxide

emphysema

characterized by permanent enlargement of the alveoli due to destruction of the alveolar walls

asthma

dyspnea, coughing, chest tightness, and/or wheezing accompanied by a sense of panic as the patient will generally feel as though they are about to suffocate

allergic asthma

most common presentation and involves an initial active inflammation of the airways even before bronchospasms set in

t lymphocytes stimulate production of IgE and recruit inflammatory cells in an immune response that causes the inflammation