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Questions and Answers
What is the first step in the process of respiration?
What is the first step in the process of respiration?
The respiratory system only functions to exchange gases.
The respiratory system only functions to exchange gases.
False
Name one function of the respiratory system aside from gas exchange.
Name one function of the respiratory system aside from gas exchange.
Regulates blood pH or allows for vocal sounds or sense of smell.
The __________ zone filters, warms, and humidifies air as it enters the body.
The __________ zone filters, warms, and humidifies air as it enters the body.
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What is the primary site of gas exchange in the lungs?
What is the primary site of gas exchange in the lungs?
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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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Air enters the body through the __________ or nostrils.
Air enters the body through the __________ or nostrils.
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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 is made of hyaline cartilage.
The epiglottis is made of hyaline cartilage.
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What are true vocal cords also known as?
What are true vocal cords also known as?
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The nasal cavity is divided into left and right halves by the nasal _______.
The nasal cavity is divided into left and right halves by the nasal _______.
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Match the following structures with their functions:
Match the following structures with their functions:
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Which structure is responsible for trapping pathogens in the throat?
Which structure is responsible for trapping pathogens in the throat?
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The cricoid cartilage is a landmark for tracheotomies.
The cricoid cartilage is a landmark for tracheotomies.
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What type of epithelium lines the nasopharynx?
What type of epithelium lines the nasopharynx?
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The trachea is ____ cm wide and ____ cm long.
The trachea is ____ cm wide and ____ cm long.
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What is the function of pleural fluid in the lungs?
What is the function of pleural fluid in the lungs?
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The right lung contains a middle lobe, while the left lung does not.
The right lung contains a middle lobe, while the left lung does not.
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What is the term for the space between the two serous membranes of the lungs?
What is the term for the space between the two serous membranes of the lungs?
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The ________ separates the two lungs.
The ________ separates the two lungs.
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Match the parts of the lung to their descriptions:
Match the parts of the lung to their descriptions:
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What is the primary function of Type II alveolar cells?
What is the primary function of Type II alveolar cells?
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The pulmonary arteries carry oxygenated blood from the lungs to the heart.
The pulmonary arteries carry oxygenated blood from the lungs to the heart.
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How many segmental bronchi are found in the right lung?
How many segmental bronchi are found in the right lung?
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The ________ is the ability of a passageway to remain unobstructed.
The ________ is the ability of a passageway to remain unobstructed.
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During inhalation, how does the pressure inside the lungs compare to atmospheric pressure?
During inhalation, how does the pressure inside the lungs compare to atmospheric pressure?
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What percentage of hemoglobin saturation occurs at a partial pressure of oxygen (PO2) of 60–100 mm Hg?
What percentage of hemoglobin saturation occurs at a partial pressure of oxygen (PO2) of 60–100 mm Hg?
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High temperatures increase the affinity of hemoglobin for oxygen.
High temperatures increase the affinity of hemoglobin for oxygen.
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What is the primary form in which carbon dioxide is transported in the blood?
What is the primary form in which carbon dioxide is transported in the blood?
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In the presence of high partial pressure of carbon dioxide, blood pH will become _____ (1), leading to _____ (2) of hemoglobin for oxygen.
In the presence of high partial pressure of carbon dioxide, blood pH will become _____ (1), leading to _____ (2) of hemoglobin for oxygen.
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What is the primary function of surfactant in the lungs?
What is the primary function of surfactant in the lungs?
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Exhalation is an active process that requires muscles to contract.
Exhalation is an active process that requires muscles to contract.
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What percentage of inhaled air is attributed to the contraction of the diaphragm?
What percentage of inhaled air is attributed to the contraction of the diaphragm?
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The diaphragm depresses by ________ cm during normal inhalation.
The diaphragm depresses by ________ cm during normal inhalation.
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Match the following pressures with their descriptions:
Match the following pressures with their descriptions:
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Which condition is characterized by an accumulation of pleural fluid?
Which condition is characterized by an accumulation of pleural fluid?
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Carbon dioxide is more soluble in water than oxygen.
Carbon dioxide is more soluble in water than oxygen.
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What is the term for the force required to change the volume of the chest wall and lungs?
What is the term for the force required to change the volume of the chest wall and lungs?
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During vigorous exercise, the diaphragm can be depressed by up to ________ cm.
During vigorous exercise, the diaphragm can be depressed by up to ________ cm.
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What happens to the partial pressure of oxygen (PO2) in the alveoli during exercise?
What happens to the partial pressure of oxygen (PO2) in the alveoli during exercise?
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What percentage saturation of hemoglobin is observed when each Hb on average has two O2 atoms bound?
What percentage saturation of hemoglobin is observed when each Hb on average has two O2 atoms bound?
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The affinity of hemoglobin for oxygen increases with a decrease in blood pH.
The affinity of hemoglobin for oxygen increases with a decrease in blood pH.
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Which form accounts for the majority of carbon dioxide transport in the blood?
Which form accounts for the majority of carbon dioxide transport in the blood?
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The binding of hemoglobin with carbon dioxide produces __________.
The binding of hemoglobin with carbon dioxide produces __________.
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Match the following factors affecting hemoglobin saturation with their effects:
Match the following factors affecting hemoglobin saturation with their effects:
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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:
- Exchanges gases.
- Regulates blood pH.
- Permits vocal sounds and the sense of smell, filters inhaled air, and excretes wastes during exhalation.
- Oto(rhino)laryngology is the study of the respiratory system.
- Cells need oxygen for aerobic cellular respiration.
Anatomy of the Respiratory System
- Structurally divided into upper and lower respiratory systems.
- Upper: Nose, nasal cavity, pharynx, and associated structures.
- Lower: Larynx, trachea, bronchi, and lungs.
- Functionally divided into conducting and respiratory zones.
- Conducting zone: Directs air, filters, warms, and humidifies air.
- Respiratory zone: Site of gas exchange (respiratory bronchioles, alveolar ducts, alveolar sacs).
Upper Respiratory System
- Nose: Made of bone, cartilage, and connective tissues. Air enters through external nares.
- Nasal Cavity: Interior space of the nose, divided by the nasal septum. Contains:
- Paranasal sinuses: Lined with mucous membranes.
- Nasal conchae: Swirl inhaled air.
- Olfactory epithelium: Sensory receptors for smells (no goblet cells).
- Pharynx: Tube of skeletal muscle, lined with mucous membrane, subdivided into:
- Nasopharynx (superior): Lined with ciliated pseudostratified columnar epithelium, sweeps mucus to the pharynx.
- Oropharynx (intermediate): Common passage for air and food, lined with non-keratinized stratified squamous epithelium, contains tonsils (trap pathogens).
- Laryngopharynx (inferior): Similar to oropharynx.
Larynx
- Tube of nine cartilages, including the thyroid cartilage (Adam's apple), epiglottis (flap of cartilage), and cricoid cartilage (landmark for tracheotomies).
- Vocal folds (true vocal cords): Form elastic ligaments, vibrate to produce sound, pitch controlled by skeletal muscles on cartilages.
- Vestibular folds (false vocal cords): Come together when holding breath.
Trachea
- 2.5 cm wide x 12 cm long tube.
- 16-20 rings of hyaline cartilage, connected by dense connective tissue, keeping trachea patent (open).
- Anterior to the esophagus. Lined with ciliated pseudostratified epithelium.
Bronchi
- Trachea splits into right and left bronchi.
- Carina: Ridge at branchpoint, sensitive mucous membrane.
- Branch into a bronchial tree, smaller tubes called terminal bronchioles, ending in lung sacs.
- Mucous membrane changes throughout the bronchial tree. The supporting cartilage and proportion of smooth muscle also change throughout the bronchial tree.
Lungs
- Wrapped in pleural membrane (two serous membranes).
- Pleural fluid reduces friction and surface tension.
- Separated by the mediastinum and its organs.
- Extend from clavicles to diaphragm.
- Base (inferior portion), apex (superior portion), concave shape conforms to the dome-shape of the diaphragm.
- Medial surfaces include:
- Hilum: Permits passage of bronchi, blood vessels, nerves, lymphatic vessels.
- Cardiac notch: Provides space for the heart, decreases size of the left lung.
- Fissures divide the lungs into lobes:
- Oblique fissure separates superior and inferior lobes.
- Horizontal fissure borders the middle lobe superiorly (right lung only).
- Lobar bronchi named after lobes (superior, middle, inferior).
- Bronchopulmonary segments: 13 in the right lung; 8 in the left.
- Lobules: Smaller compartments containing a terminal bronchiole, arteriole & venule, lymphatic vessel, and elastic connective tissue.
Respiratory Bronchioles and Alveoli
- Microscopic branches of bronchial branches.
- Lined with simple cuboidal epithelium, branching into alveolar ducts (simple squamous epithelium).
- Alveoli: Air sacs for gas exchange.
- Two types of alveolar cells:
- Type I: Simple squamous epithelium, facilitates gas diffusion.
- Type II: Nonciliated cuboidal epithelium at septa between alveoli, secretes surfactant (phospholipids + lipoproteins) to prevent sticking.
- Respiratory membrane: Alveoli + associated capillaries (very thin, 0.5 µm).
Blood Supply to the Lungs
- Pulmonary arteries: Bring deoxygenated blood from the right ventricle for oxygenation.
- Bronchial arteries: Branch from the aorta, supply oxygenated blood to lung tissue.
Gas Exchange and Ventilation
- Pulmonary ventilation: Inhalation & exhalation, regulated by pressure changes in the thoracic cavity.
- Inhalation (inspiration):
- Lungs lower pressure below atmospheric pressure.
- Diaphragm contracts and depresses, assisted by intercostal muscles to increase thoracic cavity volume.
- Intrapleural pressure is negative (lower than atmospheric pressure) and keeps the pleural membrane suctioned to the thoracic cavity wall.
- Exhalation (expiration):
- Passive process.
- Respiratory muscles relax, and elastic recoil of lung tissues increases pressure inside the lungs.
- Gases diffuse out of the body.
- Factors affecting pulmonary ventilation:
- Surfactant (insufficient surface tension can lead to respiratory distress syndrome).
- Compliance (distensibility of elastic tissues, high compliance = low effort; low compliance = high effort);
- Resistance (airway diameter, obstruction).
Lung Volumes and Capacities
- Lung volume: Measured by spirometer, output is spirogram.
- Lung capacity: Sums of specific lung volumes.
Principles of Gas Exchange
- Gases move from high to low partial pressure.
- CO2 is more soluble than O2.
- External respiration: Gas exchange between alveoli and blood (maximizes oxygenation during exercise, blood flow increases to keep up with oxygen demand)
- Internal respiration: Gas exchange between blood and tissues (CO2 constantly leaves tissues and goes into blood).
Oxygen Transport
- 98.5% of O2 carried on hemoglobin (Hb) in erythrocytes, rest is dissolved in plasma.
- Hb binds O2 reversibly.
- Affecting saturation:
- PO2 (high PO2 favors Hb-O2 formation).
- Hb affinity (affected by acidity, PCO2, temperature, 2,3 BPG, and type of hemoglobin).
Carbon Dioxide Transport
- Three main forms:
- Dissolved in plasma.
- Bound to proteins (carbamino compounds).
- Transported as bicarbonate.
- Chloride shift maintains electrical balance.
Regulation of Breathing
- Respiratory center: Medulla oblongata and pons.
- Medullary respiratory group (DRG: normal breathing, VRG: forceful breathing ).
- Pontine respiratory group influences normal breathing by affecting the DRG.
- Cortical influences: Voluntary control via cerebral cortex.
- Other influences: Chemoreceptors (central and peripheral) respond to changes in PCO2 and pH.
- Hyperventilation: Response to low blood pH, increases blood pH. Hypocapnia (low PCO2) can result, and may cause hypoxia (insufficient oxygen).
- Inflation reflex: Prevents overinflation of lungs. Baroceptors in bronchi and bronchioles, inhibiting the DRG to relax respiratory muscles.
- Other factors affecting breathing: emotions, temperature, pain, airway irritation, blood pressure.
- Exercise: Increased pulmonary perfusion, ventilation, and chemoreceptor stimulation.
Homeostatic Imbalances of Respiratory System
- Smoking can cause COPD, 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 discusses the anatomical structure of the upper and lower respiratory systems. Test your knowledge on how oxygen is utilized by the body and the significance of respiration in maintaining homeostasis.
