Respiratory Review

Alveoli

Alveoli

stores O2 from the air; composed of simple squamous epithelial that allows for rapid diffusion of CO2 out and O2 into the blood; allows for evaporation of water out of the blood

Bronchioles

order of secondary, tertiary, and terminal; lead to alveolar ducts which leads to alveolar sacs to alveoli

Epiglottis

fold of cartilage that closes the trachea during swallowing

Ciliated Epithelia

lines interior surfaces of the nasal cavity; moves mucus and trapped contaminants to the back of the throat where they are swallowed and digested in the stomach

Conchae

occur laterally from the lateral walls of the nasal cavity; covered in mucosa and highly vascular to keep air warm and distribute WBCs; traps particles that may be inhaled; if it’s cold, it dries out the airways

Larynx

provides a switching mechanism between inspiration and swallowing; houses vocal cords for speech

Pharynx

connects nasal cavity and mouth

Nasopharynx

only serves to transport air; superior to level of the soft palate

Oropharynx

both swallowed food and air pass through; posterior to oral cavity

Laryngopharynx

serves to separate food and air; merging of esophagus and trachea

Glottis

the space between the vocal cords where air moves

Trachea

passageway for air into the lungs from the pharynx; rings of cartilage prevent collapse under the negative pressure of inhalation (rigid, but flexible); lined with mucosa and cilia which propels particles towards the throat to be swallowed

Alveolar duct

serve as passageways connecting the alveolar sacs and bronchioles; collect and direct the oxygen entering the alveoli and the carbon dioxide exiting the lungs

Alveolar sac

tiny air sacs at the end of the bronchioles; alveoli are where the lungs and the blood exchange oxygen and carbon dioxide during the process of breathing

Diffusion

oxygen going into the blood and CO2 leaving the blood to go into the lungs; happens at the alveoli

Intercostal Muscles

muscle between the ribs; contraction lifts the rib cage up to open it up and decrease the pressure inside the chest, causing air to rush in; gives the lungs more space to expand

Diaphragm

sheet of muscle that separates the thoracic and abdominal cavities; flexing causes it to drop and increase the empty volume of the thoracic cavity; negative pressure causses air to rush in and fill negative space; increase in volume = decrease in pressure

Visceral pleura

the outside of the lung; attached via pleural fluid to the parietal pleura

Pleural fluid

attaches lung to the parietal pleura to keep them from collapsing

Parietal pleura

inside surface of the pleural cavity

Alveolar surfactant

decreases the tension between water molecules (breaks the cohesiveness between molecules); reduces the force trying to pull individual alveolar walls together; since the alveoli are moist, the surface tension tries to collapse them

Respiratory volumes

volume of gas in the lungs at a given time during the respiratory cycle

Tidal

amount of air moved in and out under normal resting conditions

Inspiratory reserve

amount of air that can be inspired forcibly beyond the tidal volume

Expiratory reserve

volume that can be forcibly expired beyond the tidal volume

Residual Volume

air left in lungs, even after forced expiration

Dalton’s Law of Partial Pressures

gases exert a pressure in proportion to its concentration in a mixture; eg the more oxygen you’re getting in your lungs, the higher the pressure of the oxygen trying to force its way into your blood

Oxyhemoglobin

the oxygen-loaded form of hemoglobin

Deoxyhemoglobin

form of hemoglobin without oxygen

Henry’s Law

gas will dissolve into a liquid at a rate proportional to its partial pressure and vice-versa; concentration of a gas can increase its pressure (Dalton) which increases its ability to dissolve into a liquid (Henry)

Saturation

the amount of oxygen on binding sites of hemoglobin; partial pressure of O2, blood pH, and temperature affects it

Bohr Effect

increasing acidity (lower pH or presence of CO2) weakens the bond between hemoglobin and O2; when blood gets acidic, eg from exercising, it weakens the bonds so that more O2 can get to the hardest working muscle

COPD

Chronic obstructive pulmonary disease; a group of diseases that cause airflow blockage and breathing-related problems

Ventilation-perfusion coupling

must be an efficient match between the volume of air reaching alveoli and the blood flow in pulmonary capillaries; if you have a clogged alveoli or there’s not enough oxygen in a specific area, your vessels will constrict because it wants to be efficient and only send blood to parts where there will be enough O2 for the blood and will dilate in parts where there’s sufficient O2

inflation reflex

stretch receptors prevent lung over-inflation (inspiring too much air)

What influences respiratory rate? Know both higher brain and reflexive inputs that affect breathing

Chemoreceptors monitor blood pH and O2 levels. If there’s too much CO2, breathing rate will go up. Hypothalamus processes sensory input or limbic input (emotions); cortical controls (brain control) can consciously control respiration rate but will be overridden by brain stem when CO2 gets too high; reflexive would be coughing and sneezing, inflation reflex

What are the risk factors for lung cancer? COPD?

Smoking, air pollutants, asthma, and genetics

What factors can affect the diffusion of O2 into the blood?

Pressure gradients (vary with altitude), ventilation-perfusion coupling, thickness and surface area of respiratory membrane (thickening of this membrane can lead to respiration issues)

How is O2 carried from the lungs to body tissues? What about CO2?

O2 is pulled into the airways because of negative pressure, travelling into the alveoli. The capillary beds surrounding the individual alveolar sacs carry deoxygenated blood from the heart until oxygen diffuses into it. Oxygenated blood branches into the pulmonary veins, returning oxygenated blood into the heart. The heart will send blood to the body, except for the lungs, via the aorta; CO2, moving in the concentration gradient, is diffused out the capillaries into the alveoli to be exhaled. Pressure of CO2 is higher in capillaries than in the alveoli. CO2 is exhaled since partial pressure is higher in alveoli than the environment.

What forces prevent lungs from collapsing? What might cause them to collapse?

The pleural fluid attaches the visceral pleura to the parietal pleura to keep them from collapsing. Their elastic nature causes them to contract inwards. If there’s a puncture in the parietal pleura, it can cause the fluid to leak.

How might trauma or disease affect lung function in terms of respiratory volumes?

It can prevent the lungs from fulling expanding or the ability to inhale to the greatest capacity. flow