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Questions and Answers
Which process involves gas exchange between the blood and the body's tissues?
Which process involves gas exchange between the blood and the body's tissues?
The respiratory system only functions to exchange gases.
The respiratory system only functions to exchange gases.
False
What are the main respiratory surfaces in the human body responsible for gas exchange?
What are the main respiratory surfaces in the human body responsible for gas exchange?
Alveoli
The area of the respiratory system that directs air and filters, warms, and humidifies it is known as the ________ zone.
The area of the respiratory system that directs air and filters, warms, and humidifies it is known as the ________ zone.
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Match the following parts of the respiratory system with their descriptions:
Match the following parts of the respiratory system with their descriptions:
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What is the primary function of the nasal conchae?
What is the primary function of the nasal conchae?
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The epiglottis prevents food from entering the larynx during swallowing.
The epiglottis prevents food from entering the larynx during swallowing.
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What separates the left and right halves of the nasal cavity?
What separates the left and right halves of the nasal cavity?
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The trachea is kept ____________ by C-shaped rings of cartilage.
The trachea is kept ____________ by C-shaped rings of cartilage.
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Match the following structures to their descriptions:
Match the following structures to their descriptions:
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What is the main function of pleural fluid?
What is the main function of pleural fluid?
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The left lung is larger than the right lung due to the space required for the heart.
The left lung is larger than the right lung due to the space required for the heart.
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What is the term for the area where bronchi, blood vessels, nerves, and lymphatic vessels enter the lungs?
What is the term for the area where bronchi, blood vessels, nerves, and lymphatic vessels enter the lungs?
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The fissures divide the lung into lobes.
The fissures divide the lung into lobes.
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Match the following parts of the respiratory system to their functions:
Match the following parts of the respiratory system to their functions:
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What is the main function of the diaphragm during inhalation?
What is the main function of the diaphragm during inhalation?
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Exhalation is an active process that requires energy expenditure.
Exhalation is an active process that requires energy expenditure.
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What is the term for the pressure difference between the pleural cavity and the atmosphere?
What is the term for the pressure difference between the pleural cavity and the atmosphere?
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The process by which gases diffuse from areas of high partial pressure to areas of low partial pressure is called _________.
The process by which gases diffuse from areas of high partial pressure to areas of low partial pressure is called _________.
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Match the factors affecting respiration with their descriptions:
Match the factors affecting respiration with their descriptions:
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Study Notes
Introduction to Respiration
- Respiration is the process of acquiring oxygen and eliminating carbon dioxide.
- Three steps in the human body:
- Pulmonary ventilation: Gas exchange between the atmosphere and lung tissues.
- External respiration: Gas exchange between lung tissues and blood.
- Internal respiration: Gas exchange between blood and body tissues.
- Functions of the respiratory system:
- Exchange gases.
- Regulate blood pH.
- Permit vocal sounds and sense of smell, filter inhaled air, and excrete wastes during exhalation.
- Oto(rhino)laryngology is the scientific and medical study of the respiratory system.
- Cells need oxygen for aerobic cellular respiration.
Anatomy of the Respiratory System
- Structurally divided into:
- Upper respiratory system: Nose, nasal cavity, pharynx, and associated structures.
- Lower respiratory system: Larynx, trachea, bronchi, and lungs.
- Functionally divided into:
- Conducting zone: Directs air to the respiratory zone, filters, warms, and humidifies air.
- Respiratory zone: Site of gas exchange, includes respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.
Upper Respiratory System
- Nose: Made of bone, cartilage, and connective tissue; contains the nasal cavity. Air enters via external nares (nostrils).
- Nasal cavity: Interior and anterior space of the nose; bounded by the oral cavity and nasal bones, maintains unobstructed passages. Divided into left and right halves by the nasal septum. Contains:
- Paranasal sinuses: Lined with mucous membranes, vibrate for singing/speech.
- Nasal conchae: Swirl inhaled air.
- Olfactory epithelium: Ciliated, contains sensory receptors for smells (lacks goblet cells).
- Pharynx: Tube of skeletal muscle lined with mucous membrane, starts at internal nares and continues to the cricoid cartilage; subdivided into:
- Nasopharynx: Lined with ciliated pseudostratified columnar epithelium; sweeps mucus into the pharynx.
- Oropharynx: Opening from mouth (fauces); common passage for air and food; lined with non-keratinized stratified squamous epithelium; contains tonsils (trap pathogens).
- Laryngopharynx: Similar structure to oropharynx; inferior to the oropharynx.
- Larynx: Tube comprising nine rings of cartilage.
- Thyroid cartilage: Hyaline cartilage; forms anterior surface; Adam's apple; larger growth in males.
- Epiglottis: Flap of elastic cartilage that covers the larynx entrance during swallowing.
- Cricoid cartilage: Ring of hyaline cartilage at the inferior portion of the larynx; landmark for tracheotomies.
- Vocal folds (true vocal cords): Made of non-keratinized stratified squamous epithelium; form elastic ligaments; vibrate to produce sounds; tension on ligaments changes pitch.
- Vestibular folds (false vocal cords): Come together when holding breath.
Lower Respiratory System
- Trachea: 2.5 cm wide x 12 cm long tube; 16-20 rings of hyaline cartilage; connects larynx to bronchi; cartilage keeps trachea patent (open); anterior to the esophagus; lined with ciliated pseudostratified epithelium.
- Bronchi: Trachea splits into right and left bronchi; carina (ridge) is the branch point; sensitive to triggering cough reflex. Branch into the lungs (bronchial tree); end in terminal bronchioles. Mucosal membrane changes throughout the bronchial tree.
- Lungs: Wrapped in pleural membrane (two serous membranes with a pleural cavity separating them); fluid reduces friction and provides surface tension; separated by mediastinum; extend from above clavicles to diaphragm; concave base conforms to diaphragm; superior apex. Contains:
- Hilum: Permits passage of bronchi, blood vessels, nerves, and lymphatic vessels.
- Cardiac notch: Space for heart, decreases size of left lung relative to right lung.
- Fissures: Divide lungs into lobes. Oblique fissure separates superior and inferior lobes, horizontal fissure borders middle lobe of right lung.
- Lobar bronchi: Named after lobes they branch into.
- Segmental bronchi: Each supports one bronchopulmonary segment (13 in right lung, 8 in left); damaged segments can be surgically removed.
- Lobules: Smaller compartments containing a branch of terminal bronchiole, arteriole, venule, lymphatic vessel, and elastic connective tissue.
- Respiratory bronchioles: Microscopic bronchial branches; lined with simple cuboidal epithelium that branch into alveolar ducts.
- Alveoli: Air sacs where pulmonary and external respiration occur; extensive surface area; consist of type I (simple squamous epithelium) and type II (nonciliated cuboidal epithelium at septa between alveoli) alveolar cells; secrete surfactant (phospholipids + lipoproteins) to decrease surface tension and prevent alveolar collapse. Associated with capillaries, forming respiratory membrane that facilitate gas diffusion.
- Blood supply to lungs:
- Pulmonary arteries: Bring deoxygenated blood for oxygenation; constrict in response to low oxygen; ventilation-perfusion coupling.
- Bronchial arteries: Branch from aorta; deliver oxygenated blood to lung tissue.
Gas Exchange and Ventilation
- Pulmonary ventilation: Inhalation and exhalation; regulated by pressure changes in the thoracic cavity; requires respiratory muscle contraction.
- Mechanics of inhalation: pressure inside lungs lowered below atmospheric pressure; diaphragm contracts to increase thoracic cavity volume; external intercostal muscles elevate ribs and further increase volume; intrapleural pressure remains negative to keep pleural membrane suctioned to thoracic wall.
- Mechanics of exhalation: passive process; respiratory muscles relax; elastic recoil; increased pressure in lungs relative to outside.
- Factors affecting pulmonary ventilation:
- Surfactant: Prevents alveolar collapse.
- Compliance: Lung distensibility; high compliance = low effort. Low compliance = high effort (e.g. fibrosis, injury).
- Resistance: Airway diameter, smooth muscle, obstruction/collapse.
Lung Volumes and Capacities
- Lung volumes: Specific measures of air inhaled, exhaled, or stored. Measured using a spirometer; output is a spirogram.
- Lung capacities: Sums of specific lung volumes.
Principles of Gas Exchange
- Passive diffusion from high to low partial pressure; consider gas solubility (CO2 is more soluble than O2); external respiration: maximizes oxygenation; internal respiration: oxygen moves from blood to tissues, CO2 moves from tissues to blood.
- Factors affecting rate of diffusion:
- Partial pressure gradient.
- Surface area.
- Diffusion distance.
- Molecular weight and solubility.
Oxygen Transport
- 98.5% of O2 transported by hemoglobin (Hb); rest dissolved in plasma. Hb consists of 4 protein subunits; 1 heme molecule per subunit. Hb binds O2 reversibly. Factors affecting Hb saturation:
- PO2: ~100% saturation at 60-100 mm Hg; lower at working muscles.
- Hb affinity for O2:
- Acidity (increased H+ decreases affinity).
- PCO2 (high PCO2 decreases affinity).
- Temperature (higher temperature decreases affinity).
- BPG (intermediate product of glycolysis decreases affinity).
- Type of Hb (fetal Hb has higher affinity).
Carbon Dioxide Transport
- Three forms:
- Dissolved in plasma (7%).
- Bound to proteins (23%, carbamino compounds).
- Transported as bicarbonate (70%). Chloride shift maintains electrical balance. Reverse chloride shift at pulmonary capillaries.
Regulation of Breathing
- Respiratory center: Cluster of neurons in the medulla oblongata and pons.
- Medullary respiratory group (DRG, VRG).
- Pontine respiratory group: affects normal breathing.
- Cortical influences: Voluntary control.
- Other influences:
- Chemoreceptors: Central (medulla) sense changes in PCO2/H+ in CSF; Peripheral (aortic/carotid) detect changes in blood.
- Hyperventilation: response to low blood pH. Hypocapnia can result; hypoxia may occur.
- Inflation reflex: prevents overinflation; stretch receptors in bronchi/bronchioles; inhibit further inhalation.
- Other factors: emotions, temperature, pain, airway irritation, increased blood pressure.
Exercise and Respiratory System
- Pulmonary perfusion increases during exercise.
- Ventilation increases due to limbic + proprioceptors.
- Chemoreceptors detect increased [H+] leading to increased breathing rate/depth.
Homeostatic Imbalances of the Respiratory System
- COPD: Increased mucus secretion impairs ciliary function; emphysema (destruction of alveolar walls).
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Description
This quiz covers the essentials of respiration, including the processes of gas exchange and the functions of the respiratory system. It also delves into the anatomical division of the respiratory system, highlighting both the upper and lower respiratory structures. Test your knowledge on these fundamental concepts of respiratory physiology and anatomy.
