Lab 07: Respiratory Air Flow & Volume

Primary Function of Respiratory System

Release CO2 from the body and to acquire oxygen for use by the body.

4 Steps of Respiration

Pulmonary ventilation, external respiration, transport of respiratory gases, and internal respiration.

Pulmonary Ventilation

Movement of air into and out of the lungs so that the gases in the lungs are constantly refreshed with infusions of new air and effusions of old air.

External Respiration

CO2 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. CO2 is transported from the cells of body tissues to the lungs, and oxygen is transported from the lungs to the cells of body tissues.

Internal Respiration

Occurs as oxygen diffuses from blood to the cells of the body, and CO2 diffuses from the cells for the body to the blood.

Nose

Warms and moistens entering air, provides a resonating chamber for vocalizations, cleans and filters air, and houses the olfactory receptors.

Olfactory Mucosa Epithelium

Lines a small portion of the nasal cavity—contains the receptors for smell.

Pseudostratified Ciliated Columnar Epithelium

Lines the majority of the nasal cavity—contains goblet cells & seromucous nasal glands.

Sneeze Reflex

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

Nasal Conchae

Increases surface area and help create turbulence which deflects non-gaseous particles onto the mucus coatings.

Paranasal Sinuses

Located in the frontal, sphenoid, maxillary, and ethmoid bones. Lighten the skull but are prone to inflammation.

What happens to the soft palate and uvula during swallowing?

They move superiorly to block off the nasopharynx, preventing food from entering the nasal cavity

What structure covers the larynx during swallowing to prevent food from entering the lung?

The epiglottis flaps over the larynx

What is the role of cilia in the nasopharynx?

To propel mucus toward the stomach to help clear the airway.

What is the function of the pharyngeal tonsil (adenoid)?

It contains lymphatic tissue that traps and destroys pathogens.

What are the consequences of swollen pharyngeal tonsils?

They can block air passage, force mouth breathing, and reduce air warming, filtering, and humidifying.

What do the pharyngotympanic tubes connect?

They connect the middle ear to the nasopharynx

Oropharynx & laryngopharynx is lined with…

a more protective stratified squamous as these parts of the pharynx receive both food and air.

Respiratory Zone

Site of external respiration and is 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. Here, air is humidified, warmed, and filtered/cleansed.

Vocal Folds

Or vocal cords, are housed in the larynx and are for voice production.

Laryngeal Prominence

This part of the thyroid cartilage can be seen external to the body as the Adam’s apple and is more prominent in males than females because the thyroid cartilage is stimulated by androgens during male puberty to grow larger. Estrogen also stimulates fat deposition in the necks of females that obscure their projection.

Arytenoid Cartilage

Anchor the vocal folds.

Glottis

Vocal folds and openings between them

Laryngitis

An inflammation of the vocal folds causing them to swell and vibrate incorrectly. Results in hoarse tone, and is most common caused by viral infection.

Valsalva Maneuver

Forceful exhalation against a closed airway, used to assess cardiovascular function or equalize ear pressure.

Boyle’s Law

States that pressure of a gas is inversely proportional to its volume when temperature is constant.

Trachea

Similar to other tube structures of the body, such as the GI tract, is composed of a mucosa, a submucosa, and adventitia. Elasticity allows it to move during breathing, but its cartilage rings hold it open so that air can continuously move.

Trachealis Muscle

Lies between the esophagus and trachea and contraction of the trachealis aids in the rapid movement of air and mucus out of the lung and trachea during coughing.

Alveolar Sac

Basically the cluster of alveoli coming off an alveolar duct. A single thin layer of squamous epithelial makes up the walls of the alveoli.

Alveoli

Tiny sacs in the lungs where gas exchange of O2 and CO2 occurs. Densely covered with pulomary capillaries.

Ventilation-Perfusion Coupling

Coordination of airflow (ventilation) and blood flow (perfusion) in the lungs to optimize gas exchange.

Ventilation

The amount of gas reaching the alveoli // Process of moving air in and out of the lungs to facilitate gas exchange.

Perfusion

The blood flow in the pulmonary capillaries // Flow of blood through the pulmonary capillaries allowing gas exchange with the alveoli.

Pulmonary Surfactant

Decrease surface tension in the alveoli.

Elastic Fibers

Surrounds the entire bronchial tree, including the alveoli.

The lungs take up the thoracic cavity except for the —.

mediastinum

Between the two pleural membranes is a space filled with —.

pleural fluid (lubricant secretion)

Pleurisy

Inflammation of the pleura

Pneumonia

Inflammation primarily of the alveoli in the lung.

Cardiac Notch

An indentation on the left lung that accommodates the space taken up by the heart. The left bronchus is longer and the left lung is smaller as a result.

Tertiary Bronchi

Branches of the secondary bronchi that supply air to specific segments within each lung lobe, called bronchopulmonary segments.

Lung Compliance

The “stretchiness” of the lung

Renin Angiotensin Aldosterone Pathway

Hormone cascade that helps regulate blood pressure and fluid balance by increasing sodium retention and vasoconstriction

Intrapulmonary Pressure

Pressure in the alveoli—changes as we breathe to move gases between the lungs and blood and between the lungs and the atmosphere

Intrapleural Pressure

Pressure in the pleural space or cavity

Intrapulmonary Pressure

Air pressure within the alveoli that rises and falls during breathing but always equalizes with atmospheric pressure

Intrapleural pressure is — than intrapulmonary pressure.

less

Transpulmonary Pressure

Difference between the intrapulmonary and intrapleural pressures.

Atelectasis

Collapse of part of all of a lung, leading to reduced or absent gas exchange in the affected area.

Resistance

The opposite to airflow in the respiratory passages, mainly influenced by airway diameter

Tidal Volume

The amount of air inhaled or exhaled during a normal, quiet breath.

Expired Minute Volume (MV or VE)

Total volume of air exhaled in one minute, calculated as tidal volume multiplied by respiratory rate.

Residual Volume (RV)

The amount of air remaining the lungs after a maximum exhalation, preventing lung collapse

Vital Capacity

Obtained by inspiring as deeply and rapidly as possible.

Forced Vital Capacity (FVC)

Expiring deeply and rapidly as possible.

Forced Expiratory Volume (FEV1)

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

Dalton’s Law of Partial Pressures

States that the total pressure exerted by a mix of gases will equal the sum of the partial pressures exerted independently by each of the gases of the mix.

Henry’s Law

States that the amount of gas that dissolves in a liquid is proportional to its partial pressure and solubility in that liquid

Amount of air expelled with each normal resting breath.

Tidal Volume (V_T or TV)

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

Inspiratory Reserve Volume (IRV)

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

Expiratory Reserve Volume (ERV)

Amount of air remaining in the lungs after a max forced expiration.

Residual Volume (RV)

Max amount of air contained in the lungs after a max inspiration.

Vital Capacity (VC)

Maximum amount of air contained in the lungs after a max inspiration.

Total Lung Capacity (TLC)

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

Inspiratory Capacity (IC)

Max amount of air that can be expired after normal tidal expiration

Expiratory Capacity (EC)

Volume of air remaining in the lungs after a normal tidal expiration

Function (Forced) Residual Capacity (FRC)

Hyperbaric Oxygen

Medical treatment that involves breathing pure oxygen in a pressurized chamber to enhance oxygen delivery to tissues

Hemoglobin

Made up of four iron-containing heme groups each bound to a polypeptide chain subunit // Protein in red blood cells that binds to oxygen and transports it from the lungs to the tissues.

Affinity

How easily oxygen binds to the hemoglobin

Bohr Effect

The phenomenon where increased CO2 or decreased pH reduced hemoglobin’s affinity for oxygen, promoting oxygen release to tissues

Haldane Effect

Phenomenon where oxygen binding to hemoglobin reduced its ability to carry CO2, enhancing CO2 release in the lungs

Hypoxia

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

Anemic Hypoxia

Poor oxygen delivery 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 O2 is delivered but the body cells are unable to use it such as is the case when metabolic poisons (cyanide) are administered.

Hypoxemia Hypoxia

Indicated when the partial pressure of dissolved O2 in the arteriole blood is low and is commonly caused by disordered ventilation-perfusion coupling, pathological pulmonary ventilation impairment, and breathing air deficient in O2.

Carbon Monoxide Poisoning

Type of hypoxemic hypoxia often caused by breathing smoke from fire or inhaling fume of combustion.

Ventral Respiratory Group

Cluster of neurons in the medulla that controls forced breathing by stimulating accessory respiratory muscles

Dorsal Respiratory Group

Medullary center that primarily controls the basic rhythm of quiet breathing by stimulating the diaphragm and external intercostals.

Eupnea

Clinical term for a normal breathing rate (about 15 breaths per minute)

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 CO2 levels in the blood

Hyperpnea

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

Hypocapnia

Low blood CO2 levels

Alkalosis

High blood pH

Hypocapnia & alkalosis cause…

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

Apnea

Clinical term for breathing cessation

Spirometry

Pulmonary function test that measures lung volumes and airflow to assess respiratory health and diagnose conditions like asthma or COPD

Chronic Obstructive Pulmonary Disease (COPD)

Progressive respiratory disorder characterized by airflow limitation, commonly caused by chronic bronchitis or emphysema

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 CO2

Emphysema

Characterized by permanent enlargement of the alveoli due to destruction of the alveolar walls.

Asthma

Characterized by dyspnea, coughing, chest tightness, and/or wheezing accompanied by a sense of panic & feeling of suffocation.

Allergic Asthma

Most common presentation and involves an initial inflammation of the airways even before bronchospasm set in.

How to identify obstructive lung disease from FVC/FEV1?

Low FEV1 and low FEV1/FVC ratio (<70%)

Where to place markers on the spirometry graph with FVC?

Start of tidal exhalation and end of forced exhalation

Normal capacities but very low tidal volume—what’s wrong?

Likely a neuromuscular issue or restricted chest movement