Respiratory Physiology Quiz

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary relationship described by Boyle’s law in the context of gas behavior?

Temperature affects pressure and volume

Pressure varies directly with volume

Pressure varies inversely with volume (correct)

Gas does not fill its container

What occurs in the thoracic cavity during normal quiet inspiration?

The lung volume increases by approximately 500 ml (correct)

The thoracic cavity volume decreases

No air flows into the lungs

The pressure in the thoracic cavity rises

Which muscles are primarily involved in forced inspirations during exercise?

Trapezius and latissimus dorsi

Abdominals and internal intercostals

Accessory muscles like scalene and sternocleidomastoid (correct)

Diaphragm and external intercostals

What happens to the pressure in the lungs (Ppul) during normal inspiration compared to atmospheric pressure (Patm)?

Ppul decreases to -1 mm Hg Signup and view all the answers

What is the effect on Pip (intrapleural pressure) during inspiration?

Pip falls to about -6 mm Hg Signup and view all the answers

What is the primary difference in partial pressures of oxygen (PO2) between tissues and arterial blood?

Tissue PO2 is always lower than arterial blood PO2. Signup and view all the answers

How is the majority of oxygen (O2) transported in the blood?

Loosely bound to hemoglobin in red blood cells Signup and view all the answers

What is the composition of hemoglobin in terms of oxygen transport?

Each hemoglobin can bind four O2 molecules. Signup and view all the answers

What happens to carbon dioxide (CO2) during tissue gas exchange?

CO2 diffuses from tissues into blood. Signup and view all the answers

What is the approximate partial pressure of CO2 (PCO2) in venous blood returning to the heart?

45 mm Hg Signup and view all the answers

Which of the following structures is part of the lower respiratory system?

Trachea Signup and view all the answers

What is the primary function of the conducting zone?

Transport air and humidify it Signup and view all the answers

Which structures are included in the respiratory zone?

Alveoli and alveolar ducts Signup and view all the answers

What condition is characterized by inflammation of the larynx?

Laryngitis Signup and view all the answers

Which of the following is a common symptom of smoker’s cough?

Coughing up mucus Signup and view all the answers

The Heimlich maneuver is typically used in what situation?

To expel an obstructed airway Signup and view all the answers

What type of epithelial tissue primarily composes the tracheal wall?

Pseudostratified ciliated columnar epithelium Signup and view all the answers

What do alveoli primarily facilitate?

Gas exchange Signup and view all the answers

What process occurs during quiet expiration?

Relaxation of inspiratory muscles Signup and view all the answers

What role do abdominal wall muscles play during forced expiration?

They increase intra-abdominal pressure Signup and view all the answers

What is the main source of airway resistance during ventilation?

Friction in airways Signup and view all the answers

How does airway resistance affect the flow of air during normal breathing?

Increases the effort needed for breathing Signup and view all the answers

What is the consequence of increased intrapulmonary pressure during expiration?

Air exits the lungs Signup and view all the answers

Which process is NOT considered a nonrespiratory air movement?

Deep breathing Signup and view all the answers

What primarily influences lung compliance?

Alveolar surface tension Signup and view all the answers

What defines the pressure gradient needed for airflow during normal breathing?

1–2 mm Hg Signup and view all the answers

What happens to the arterioles when local alveolar PO is high?

They dilate to increase perfusion. Signup and view all the answers

In which circumstance do bronchioles constrict?

When alveolar PCO is high. Signup and view all the answers

What role do pulmonary arterioles play during low alveolar PCO?

They dilate to increase blood flow. Signup and view all the answers

How do systemic arterioles respond to high oxygen levels?

They constrict to reduce blood flow. Signup and view all the answers

What is the primary purpose of autoregulation in pulmonary gas exchange?

To synchronize ventilation and perfusion. Signup and view all the answers

What effect does poor alveolar ventilation have on local alveolar PO and PCO?

Reduces PO and increases PCO. Signup and view all the answers

What causes regional variations in ventilation and perfusion?

The effect of gravity on blood and air flow. Signup and view all the answers

What prevents balanced ventilation-perfusion in all alveoli?

Unventilated areas due to plugged alveolar ducts. Signup and view all the answers

How is the majority of carbon dioxide transported in the blood?

As bicarbonate ions in plasma Signup and view all the answers

What reaction does carbonic anhydrase primarily catalyze in red blood cells?

Formation of bicarbonate from carbon dioxide and water Signup and view all the answers

What is the process referred to when bicarbonate ions diffuse out of red blood cells and chloride ions move in?

Chloride shift Signup and view all the answers

How does the Haldane effect influence the transportation of carbon dioxide?

Encourages CO2 exchange at tissues when hemoglobin is less saturated Signup and view all the answers

What effect does CO2 entering the blood have in tissues?

Causes more O2 to dissociate from hemoglobin Signup and view all the answers

What occurs in the pulmonary capillaries in relation to bicarbonate ions?

Bicarbonate ions are converted back into carbon dioxide Signup and view all the answers

What is the role of reduced hemoglobin in the context of carbon dioxide transport?

It enhances the formation of carbaminohemoglobin Signup and view all the answers

What type of binding occurs between carbon dioxide and hemoglobin?

Chemically binds to globin molecules Signup and view all the answers

Study Notes

Introduction to the Respiratory System

The respiratory system absorbs oxygen and excretes carbon dioxide.
Its primary function is gas exchange, supplying cells with oxygen and disposing of carbon dioxide from cellular respiration.
To achieve this, the respiratory and cardiovascular systems work together.
Respiration is a collective term for four processes, carried out by both systems.

Four Processes of Respiration

Pulmonary Ventilation (Breathing): The process of moving air into and out of the lungs (inspiration and expiration).
Pulmonary Gas Exchange: Oxygen diffuses from the lungs into the blood, while carbon dioxide diffuses from the blood into the lungs.
Transport of Respiratory Gases: The cardiovascular system transports respiratory gases in the blood. Oxygen is transported from the lungs to the tissue cells, and carbon dioxide is transported from the tissue cells to the lungs.
Tissue Gas Exchange: Oxygen diffuses from the blood to the tissue cells, while carbon dioxide diffuses from the tissue cells to the blood. The cells then use oxygen to produce carbon dioxide.

Major Respiratory Organs and Structures

Nose: Supported by bone and cartilage; internal nasal cavity, nasal septum, olfactory epithelium.
Paranasal Sinuses: Mucosa-lined, air-filled cavities in cranial bones, surrounding nasal cavity, function to lighten the skull and warm, moisten, and filter incoming air.
Pharynx: Passageway connecting the nasal cavity, larynx, and oral cavity, to the esophagus; has three subdivisions (nasopharynx, oropharynx, and laryngopharynx). Houses tonsils (lymphoid tissue masses) for protection against pathogens.
Larynx: Connects the pharynx to the trachea and prevents food from entering the lower respiratory tract; houses vocal folds (true vocal cords). Includes epiglottis, cartilage, and vocal folds.
Trachea: Flexible tube connecting the larynx to the bronchial tree; contains C-shaped cartilages.
Bronchial Tree: A branching system of tubes within the lungs: right and left main bronchi, which subdivide into lobar and segmental bronchi and bronchioles. Bronchioles have smooth muscle, affecting expiration.
Alveoli: Microscopic air sacs where gas exchange occurs. Walls are thin simple squamous epithelium, and are associated with pulmonary capillaries (an extensive network of tiny blood vessels). Alveolar cells produce surfactant to reduce surface tension, preventing alveolar collapse
Lungs: Paired composite organs that flank the mediastinum in the thorax. Composed of alveoli and respiratory passageways. Stroma is elastic connective tissue, allowing recoil during expiration.
Pleurae: Serous membranes; parietal pleura lines the thoracic cavity, and visceral pleura covers the external lung surfaces. Produce lubricating fluid within compartmentalized lungs

Conducting vs. Respiratory Zones

Conducting Zone: Conduits that transport air. They contain structures that cleanse, warm, and humidify incoming air (nose, nasal cavity, pharynx, larynx, trachea, bronchial tree).
Respiratory Zone: Sites of gas exchange (alveolar ducts, respiratory bronchioles, and alveoli)

Pressure Relationships in the Thoracic Cavity

Atmospheric pressure (P_atm): Pressure exerted by air surrounding the body (at sea level, 760 mm Hg).
Intrapulmonary pressure (P_pul): Pressure within the alveoli, fluctuating during breathing. Equalizes with P_atm at the end of each breath (inspiration and expiration).
- Inspiration: P_pul < P_atm to suck air into lungs.
- Expiration: P_pul > P_atm to push air out of lungs.
Intrapleural Pressure (P_ip): Pressure within the pleural cavity, always negative relative to atmospheric and intrapulmonary pressures. This negative pressure keeps the lungs expanded against the chest wall.

Pulmonary Ventilation

Inspiration: Active process, requires muscle contraction to enlarge thoracic cavity and lower lung pressure below atmospheric pressure to pull air into the lungs. Primarily involves diaphragm and external intercostal muscles.
Expiration: A passive process, involves relaxation of inspiratory muscles, elastic recoil of the lungs, and surface tension. Also involves active process of expelling a larger volume of air in deep/forced expiration (e.g., forced exhalation, exercise). These involve more muscles, including abdominal muscles and internal intercostals.

Pulmonary Gas Exchange

Factors include: partial pressure gradients (O2 and CO2), membrane thickness and surface area.
Partial pressure gradients promote diffusion of O2 into blood, and CO2 into lungs.
Thickness is very thin (0.5-1 µm).
Large surface area due to millions of alveoli.

Tissue Gas Exchange

Partial pressure gradients dictate diffusion from blood into tissues (O2) and from tissues into blood (CO2).
Partial pressures reversed compared to pulmonary gas exchange, pushing oxygen from the blood into tissues and pulling CO2 from tissues to blood.

Oxygen Transport

Oxygen is carried in two ways: dissolved in plasma and loosely bound to hemoglobin.
Hemoglobin carries 98.5% of oxygen in blood.
Factors affecting Hb saturation include temperature, pH, partial pressure of carbon dioxide (PCO2), and 2,3-bisphosphoglycerate (BPG) concentration

Carbon Dioxide Transport

CO2 is transported in three forms: dissolved in plasma, chemically bound to hemoglobin (carbaminohemoglobin), and as bicarbonate ions (HCO3-).

Ventilation-Perfusion Coupling

Ventilation = amount of air reaching alveoli
Perfusion= amount of blood flow through pulmonary capillaries.
Matching required for efficient gas exchange. Controlled by local autoregulation mechanisms (e.g., changes in Po2 or Pco2 affecting arteriolar or bronchiolar diameters).

Respiratory Centers in the Brain Stem

Control breathing rate and depth.
Respond to chemical stimuli (O2, CO2, pH) and neural input.
Include Dorsal Respiratory Group (DRG) and Ventral Respiratory Group (VRG).

Neural and Chemical Influences on Respiratory Centers

Other receptors and stimuli (emotional stimuli, pain, receptors in muscles and joints). Peripheral and central chemoreceptors detect changes in Po2, Pco2, and pH.

Factors Influencing Breathing Rate and Depth

Chemical factors: arterial Pco2, Po2, and pH.
Influence of Po2 is less powerful than Pco2 in influencing breathing rate and depth. pH also affects respiratory rate and depth, though not as directly as CO2.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on the principles of respiratory physiology, including Boyle's Law, gas exchange, and the mechanics of breathing. This quiz covers the role of pressure changes in the thoracic cavity, as well as oxygen and carbon dioxide transport mechanisms in the body.