ch2 respiratory system 2025

What are the major functions of the respiratory system?

To supply the body with O2 for cellular respiration and dispose of CO2, a waste product of cellular respiration.

How are the respiratory and circulatory systems related?

They are closely coupled.

What are the four processes involved in respiration?

1. Pulmonary ventilation (breathing) 2. External respiration 3. Transport of O2 and CO2 in blood 4. Internal respiration.

What structures comprise the upper respiratory system?

Nose, nasal cavity, paranasal sinuses, and pharynx.

What structures comprise the lower respiratory system?

Larynx, trachea, bronchi and branches, lungs, and alveoli.

What are the functions of the conducting airways?

To conduct air to the lungs, humidify, and cleanse the air.

What are the main sites of gas exchange in the respiratory system?

Respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.

What is the external part of the nose called?

The external nose, which includes the nostrils or nares.

What is the function of the respiratory mucosa in the nasal cavity?

It secretes mucus to trap and destroy bacteria, and helps warm, moisten, and filter the air.

What is the role of the olfactory mucosa?

It contains olfactory epithelium with receptors for the sense of smell.

What is the pharynx and its primary function?

A funnel-shaped muscular tube that connects the nasal cavity and mouth to the larynx and esophagus, serving as a passageway for air and food/liquids.

What are the three regions of the pharynx?

Nasopharynx, oropharynx, and laryngopharynx.

What are the three functions of the larynx?

1. Provides a patent airway 2. Routes air and food into proper channels 3. Voice production.

What is the larynx commonly referred to as?

The voice box.

What is the structure of the larynx primarily composed of?

Nine hyaline cartilages connected by membranes and ligaments.

What is the thyroid cartilage and its significance?

It is a large, shield-shaped cartilage that resembles an upright open book; the laryngeal prominence (Adam's apple) is part of it.

What is the cricoid cartilage?

A ring-shaped cartilage that forms part of the larynx.

What is the role of the tonsils located in the pharynx?

They are involved in the immune response.

What is the function of the nasal conchae?

To increase the surface area of the nasal cavity, enhancing air filtration and humidification.

What is the significance of the paranasal sinuses?

They surround the nasal cavity, lighten the skull, and moisten the air.

What type of epithelium lines the respiratory mucosa?

Ciliated columnar epithelium containing Goblet cells.

What is the function of vibrissae in the nasal cavity?

They are hairs that help trap larger particles from entering the respiratory system.

What type of cartilage is the epiglottis made of?

Elastic cartilage.

What are the vocal ligaments?

They form the core of the vocal folds, also known as true vocal cords.

What is the glottis?

The opening between the vocal folds.

How is sound produced in the larynx?

Sound is produced as the vocal folds vibrate when air rushes up from the lungs.

What are vestibular folds?

Also known as false vocal cords, they are superior to the vocal folds and help close the glottis during swallowing.

What determines the pitch of the voice?

Pitch is determined by the length and tension of the vocal cords.

What factors influence the loudness of the voice?

Loudness depends on the force of air.

How do the chambers of the pharynx and oral, nasal, and sinus cavities affect sound?

They amplify and enhance sound quality.

What is the trachea commonly referred to as?

The windpipe.

How long and wide is the trachea?

About 4 inches long and 3/4 inch in diameter.

What are the three layers of the tracheal wall?

Mucosa, submucosa, and adventitia.

What is the function of the trachealis muscle?

It connects the posterior parts of the cartilage rings and contracts during coughing to expel mucus.

What is the carina?

The last tracheal cartilage that is expanded and found at the point where the trachea branches into two main bronchi.

What happens if a foreign object contacts the mucosa of the carina?

It triggers violent coughing.

What is the Heimlich maneuver?

A procedure in which air in a victim's lungs is used to expel an obstructing piece of food.

What is the bronchial tree?

The branching structure formed by the trachea dividing into primary bronchi, which further divide into secondary and tertiary bronchi, and then into bronchioles.

What are the two zones of the respiratory system?

The conducting zone (nose to terminal bronchioles) and the respiratory zone (respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli).

What is the primary function of alveoli?

They are the sites of actual gas exchange.

What is the respiratory membrane?

The blood-air barrier consisting of alveolar and capillary walls along with their fused basement membranes.

What is the role of type II alveolar cells?

They secrete surfactant and antimicrobial proteins.

What is surfactant and why is it important?

A detergent-like lipid and protein complex that reduces surface tension of alveolar fluid, preventing alveolar collapse.

What condition can result from insufficient surfactant in premature infants?

Infant respiratory distress syndrome (IRDS).

What is Boyle's Law?

The relationship between pressure and volume of a gas, stating that pressure varies inversely with volume.

What occurs during inspiration?

Gases flow into the lungs due to the contraction of inspiratory muscles, increasing thoracic volume and decreasing pressure.

What happens during quiet expiration?

It is normally a passive process where inspiratory muscles relax, thoracic cavity volume decreases, and lungs recoil.

What is spirometry?

A measure of pulmonary function that assesses the volume of air exchanged during breathing and respiratory rate.

What are the four respiratory volumes used to assess respiratory status?

Tidal volume (TV), inspiratory reserve volume (IRV), expiratory reserve volume (ERV), and residual volume (RV).

What is tidal volume (TV)?

The amount of air moved into and out of the lung with each breath, averaging ~500 ml.

What is inspiratory reserve volume (IRV)?

The amount of air that can be inspired forcibly beyond the tidal volume, typically ranging from 2100 to 3200 ml.

What is expiratory reserve volume (ERV)?

The amount of air that can be forcibly expelled from the lungs, typically ranging from 1000 to 1200 ml.

What is residual volume (RV)?

The amount of air that always remains in the lungs, necessary to keep alveoli open.

What are respiratory capacities?

Combinations of two or more respiratory volumes that provide information on a person's respiratory status.

What is inspiratory capacity (IC)?

The sum of tidal volume (TV) and inspiratory reserve volume (IRV).

What is functional residual capacity (FRC)?

The sum of residual volume (RV) and expiratory reserve volume (ERV).

What is vital capacity (VC)?

The sum of tidal volume (TV), inspiratory reserve volume (IRV), and expiratory reserve volume (ERV).

What is total lung capacity (TLC)?

The sum of all lung volumes: tidal volume (TV) + inspiratory reserve volume (IRV) + expiratory reserve volume (ERV) + residual volume (RV).

What is anatomical dead space?

The portion of the respiratory system that does not contribute to gas exchange, consisting of air that remains in passageways, approximately 150 ml out of 500 ml tidal volume.

What is alveolar dead space?

The space occupied by nonfunctional alveoli, which can occur due to collapse or obstruction.

What is total dead space?

The sum of anatomical dead space and alveolar dead space.

What does Dalton's law of partial pressures state?

The total pressure exerted by a mixture of gases is equal to the sum of the pressures exerted by each gas in the mixture.

What is Henry's law in relation to gas mixtures?

Each gas will dissolve in a liquid in proportion to its partial pressure; higher partial pressure leads to more gas dissolving.

Which gas is more soluble in water, CO2 or O2?

CO2 is 20 times more soluble in water than O2.

What happens to nitrogen (N2) under high pressure?

Under high pressure, nitrogen can enter the blood, which can lead to decompression sickness if a diver ascends too rapidly.

What is the purpose of a hyperbaric chamber?

To increase pressure to cause more oxygen to dissolve in the blood, used for conditions like decompression sickness and carbon monoxide poisoning.

What is external respiration?

The diffusion of gases between blood and lungs, driven by partial pressure gradients.

What is internal respiration?

The diffusion of gases between blood and tissues, also driven by partial pressure gradients but in the opposite direction of external respiration.

How do partial pressures of oxygen and carbon dioxide differ in internal respiration compared to external respiration?

In internal respiration, tissue PO2 is lower than arterial blood PO2, causing oxygen to move from blood to tissues, while tissue PCO2 is higher than arterial blood PCO2, causing CO2 to move from tissues to blood.

How is molecular O2 carried in blood?

In two ways: 1.5% is dissolved in plasma and 98.5% is loosely bound to hemoglobin in red blood cells.

What is the composition of a hemoglobin (Hb) molecule?

Each Hb molecule is composed of four polypeptide chains, each with an iron-containing heme group, allowing it to transport four oxygen molecules.

What is oxyhemoglobin?

Oxyhemoglobin (HbO2) is the combination of hemoglobin and oxygen.

What is reduced hemoglobin?

Reduced hemoglobin (deoxyhemoglobin, HHb) is hemoglobin that has released oxygen.

What factors influence hemoglobin saturation with oxygen?

The most important factor is the partial pressure of oxygen (PO2), along with temperature, blood pH, and PCO2.

What happens to hemoglobin's oxygen affinity when temperature, blood pH, or PCO2 increases?

An increase in any of these factors decreases hemoglobin's oxygen affinity, shifting the oxygen-hemoglobin dissociation curve to the right, leading to more oxygen unloading.

What are the three forms of carbon dioxide transport in blood?

1. Dissolved in plasma (7 to 10% as PCO2), 2. Chemically bound to hemoglobin (over 20% as carbaminohemoglobin), 3. As bicarbonate ions in plasma (about 70%).

How is bicarbonate formed in the blood?

Bicarbonate is formed when CO2 combines with water to create carbonic acid (H2CO3), which quickly dissociates into bicarbonate and hydrogen ions.

What is carbon monoxide poisoning and its effects on hemoglobin?

Carbon monoxide (CO) is a colorless, odorless gas that binds to hemoglobin with a higher affinity than oxygen, displacing O2 and reducing the amount of oxygen transported by hemoglobin.

What is the treatment for carbon monoxide poisoning?

The treatment is to administer pure oxygen.

What regulates respiratory rhythms?

Respiratory rhythms are regulated by higher brain centers, chemoreceptors, and other reflexes, involving neurons in the medulla and pons.

What role does the cerebral cortex play in respiration?

The cerebral cortex allows for voluntary control of breathing to a certain extent.

What are the chemical factors affecting the depth and rate of inspiration?

Changing levels of PCO2, PO2, and pH are the most important chemical factors.

Where are central chemoreceptors located?

Central chemoreceptors are located throughout the brain stem.

Where are peripheral chemoreceptors found?

Peripheral chemoreceptors are found in the aortic arch and carotid arteries.

What is the most powerful respiratory stimulant?

Increased levels of CO2 are the most powerful respiratory stimulant.

What is the significance of the oxygen-hemoglobin dissociation curve?

It illustrates the proportion of hemoglobin saturated with oxygen, which depends on the partial pressure of oxygen.

What happens to hemoglobin in pulmonary capillaries?

In pulmonary capillaries, the partial pressure of oxygen (pO2) is high, leading to a lot of O2 binding to hemoglobin.

What occurs in tissues regarding oxygen and hemoglobin?

In tissues, the partial pressure of oxygen (pO2) is low, resulting in oxygen being unloaded from hemoglobin.

What percentage of oxygen is unloaded from hemoglobin at rest?

At rest, only 25% of oxygen unloads from hemoglobin, which serves as a reserve.

What happens to oxygen unloading during muscle contraction?

During muscle contraction, more oxygen is unloaded from hemoglobin.

What happens to respiratory rate when CO2 levels increase?

The respiratory rate increases.

What altitude can trigger acute mountain sickness (AMS)?

Quick travel to altitudes above 2400 meters (8000 feet) may trigger AMS.

What are common symptoms of acute mountain sickness (AMS)?

Headaches, shortness of breath, nausea, and dizziness.

What severe conditions can occur due to acute mountain sickness (AMS)?

Lethal cerebral and pulmonary edema may occur.

What is acclimatization in relation to high altitude?

Acclimatization involves respiratory and hematopoietic adjustments made with long-term moves to high altitude.

How much does minute ventilation increase during acclimatization to high altitude?

Minute ventilation increases by 2-3 L/min higher than at sea level.

How do chemoreceptors respond to changes in PO2 at high altitudes?

Chemoreceptors become more responsive to PCO2 when PO2 declines.

What stimulates increased RBC production at high altitudes?

A decline in blood O2 stimulates the kidneys to produce erythropoietin (EPO).

What is asthma characterized by?

Chronic airway inflammation, coughing, wheezing, and chest tightness.

What percentage of the population in the USA is affected by asthma?

Asthma affects 3-5% of the population in the USA, more commonly in children.