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Questions and Answers
What is the primary function of the alveoli in the respiratory system?
What is the primary function of the alveoli in the respiratory system?
What role does the epiglottis play in the respiratory system?
What role does the epiglottis play in the respiratory system?
Which of the following structures is NOT considered a part of the respiratory system?
Which of the following structures is NOT considered a part of the respiratory system?
What characterizes the right primary bronchus compared to the left?
What characterizes the right primary bronchus compared to the left?
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What happens during the process of expiration?
What happens during the process of expiration?
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What drives the movement of oxygen from the alveoli into the blood?
What drives the movement of oxygen from the alveoli into the blood?
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What is the state of blood leaving the lungs in terms of oxygen and carbon dioxide levels?
What is the state of blood leaving the lungs in terms of oxygen and carbon dioxide levels?
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How does the concentration of carbon dioxide in blood returning from tissues compare to that in the alveoli?
How does the concentration of carbon dioxide in blood returning from tissues compare to that in the alveoli?
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What happens to carbon dioxide in pulmonary capillary blood?
What happens to carbon dioxide in pulmonary capillary blood?
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What is the concentration relationship of oxygen in the alveoli compared to that in pulmonary capillary blood?
What is the concentration relationship of oxygen in the alveoli compared to that in pulmonary capillary blood?
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The respiratory system is responsible for gas exchange primarily in the alveoli.
The respiratory system is responsible for gas exchange primarily in the alveoli.
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The epiglottis is primarily made of muscle tissue.
The epiglottis is primarily made of muscle tissue.
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The left lung has three lobes.
The left lung has three lobes.
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Inspiration is an active process that involves the contraction of the diaphragm.
Inspiration is an active process that involves the contraction of the diaphragm.
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Ciliated mucosa in the trachea helps trap dust and debris before it reaches the lungs.
Ciliated mucosa in the trachea helps trap dust and debris before it reaches the lungs.
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The alveoli contain less oxygen than the blood entering them.
The alveoli contain less oxygen than the blood entering them.
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Oxygen moves from an area of lower concentration to an area of higher concentration during external respiration.
Oxygen moves from an area of lower concentration to an area of higher concentration during external respiration.
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Blood returning from tissues has lower concentrations of carbon dioxide than the air in the alveoli.
Blood returning from tissues has lower concentrations of carbon dioxide than the air in the alveoli.
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Blood leaving the lungs is rich in carbon dioxide and poor in oxygen.
Blood leaving the lungs is rich in carbon dioxide and poor in oxygen.
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Pulmonary capillary blood gives up oxygen to the alveoli.
Pulmonary capillary blood gives up oxygen to the alveoli.
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Gas exchange occurs in the alveoli of the lungs.
Gas exchange occurs in the alveoli of the lungs.
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The process of external respiration involves the exchange of gases between the alveoli and the pulmonary capillaries.
The process of external respiration involves the exchange of gases between the alveoli and the pulmonary capillaries.
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Carbon dioxide diffuses from the pulmonary capillary blood into the alveoli.
Carbon dioxide diffuses from the pulmonary capillary blood into the alveoli.
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Oxygen always moves into the blood regardless of the concentration gradient.
Oxygen always moves into the blood regardless of the concentration gradient.
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Blood that has gained oxygen is described as oxygen-poor.
Blood that has gained oxygen is described as oxygen-poor.
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Study Notes
Respiratory System Overview
- The respiratory system's primary function is gas exchange—taking in oxygen and releasing carbon dioxide.
- This exchange occurs within the lungs, specifically within the alveoli.
- Air passages purify, warm, and humidify incoming air.
Respiratory System Organs
- Nose: Warms, filters, and humidifies incoming air. Includes nasal cavity and external nares (nostrils).
- Pharynx: Muscular passageway for both air and food, divided into the nasopharynx, oropharynx, and laryngopharynx.
- Larynx: Also known as the voice box, responsible for voice production. Built of eight rigid hyaline cartilages and the epiglottis (elastic flap). Contains vocal cords.
- Trachea: Connects the larynx to the bronchi. Lined with ciliated mucosa to remove debris. Reinforced by C-shaped hyaline cartilage.
- Bronchi: Branching tubes that carry air from the trachea to the lungs. Primary bronchi branch into secondary and tertiary bronchi. Bronchi gradually lose cartilage and become bronchioles.
- Lungs – Alveoli: The alveoli are the tiny air sacs in the lungs where gas exchange takes place. The lungs sit in the thoracic cavity, with the apex near the clavicle and base on the diaphragm.
Nasal Cavity Anatomy
- Lateral walls: Have projections called conchae, increasing surface area.
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Palate: Separates the nasal cavity from the oral cavity.
- Anterior hard palate (bone)
- Posterior soft palate (muscle)
- Respiratory mucosa: Lines the cavity, moistening air and trapping foreign particles.
Paranasal Sinuses
- A group of four paired air-filled spaces surrounding the nasal cavity. Named for the facial bones they are in (frontal, maxillary, ethmoid, sphenoidal).
- Functions: Lighten the skull, act as resonance chambers for speech, produce mucus that drains into the nasal cavity.
Pharynx (Throat)
- The pharynx acts as a common passageway for air and food divided into three regions:
- Nasopharynx
- Oropharynx
- Laryngopharynx
Larynx (Voice Box)
- The larynx routes air and food into proper channels.
- Plays a role in speech.
- Made of eight rigid hyaline cartilages and a spoon-shaped elastic cartilage (epiglottis).
Structures of the Larynx
- Thyroid cartilage: Largest hyaline cartilage, protrudes anteriorly (Adam's apple).
- Epiglottis: Superior opening of the larynx, routes food to the larynx and air toward the trachea.
- Vocal cords (vocal folds): Vibrate with expelled air to create sound (speech).
- Glottis: Opening between vocal cords.
Trachea (Windpipe)
- Connects larynx with bronchi
- Lined with ciliated mucosa.
- Beats continuously in the opposite direction of incoming air, expelling mucus loaded with dust and debris.
- Walls reinforced with C-shaped hyaline cartilage.
Lungs
- Occupy most of the thoracic cavity.
- Apex is near the clavicle.
- Base rests on the diaphragm.
- Each lung is divided into lobes by fissures.
- Left lung: two lobes
- Right lung: three lobes
Coverings of the Lungs
- Visceral pleura: Covers the lung surface.
- Parietal pleura: Lines the walls of the thoracic cavity.
- Pleural fluid: Fills the area between layers of pleura to allow gliding.
Respiratory Tree Divisions
- Primary bronchi
- Secondary bronchi
- Tertiary bronchi
- Bronchioles
- Terminal bronchiole that lead to alveoli
Primary Bronchi
- Formed via trachea division
- Enter lungs at the hilus (medial depression).
- Right bronchus is wider, shorter, and straighter than the left.
Bronchioles
- The smallest branches of the bronchi.
- All but the smallest branches have reinforcing cartilage.
Respiratory Zone
- The site of gas exchange.
- Structures: alveolar duct, alveolar sac, alveolus.
Respiratory Membrane (Air-Blood Barrier)
- Thin squamous epithelial layer lining alveolar walls.
- Pulmonary capillaries cover external surfaces of alveoli.
Events of Respiration
- Pulmonary ventilation: Moving air in and out of the lungs
- External respiration: Gas exchange between pulmonary blood and alveoli
- Internal respiration: Gas exchange between blood and tissue cells in systemic capillaries.
Mechanics of Breathing (Pulmonary Ventilation)
- A completely mechanical process
- Depends on volume changes in the thoracic cavity.
- Volume changes lead to pressure changes which lead to the flow of gases to equalize pressure.
- Two phases: inspiration (air entering lungs) and expiration (air leaving lungs).
Inspiration
- Diaphragm and intercostal muscles contract.
- The size of the thoracic cavity increases.
- External air is pulled into the lungs due to an increase in intrapulmonary volume.
- Rib elevation
- Diaphragm contraction
Expiration
- Largely a passive process that depends on natural lung elasticity.
- As muscles relax, air is pushed out of the lungs.
- Forced expiration can occur by contracting internal intercostal muscles to depress the rib cage.
- Rib depression
- Diaphragm relaxation
Non-respiratory Air Movements
- Can be caused by reflexes or voluntary actions.
- Examples: Cough, sneeze, laugh, cry, hiccups, yawn.
Factors Influencing Respiratory Rate and Depth
- Physical factors: Increased body temperature, exercise, talking, coughing, volition (conscious control), emotional factors.
- Chemical factors: Carbon dioxide levels (increased CO2 levels stimulate respiration) and oxygen levels (decreased O2 stimulates respiration.) Chemical control through chemoreceptors in the aorta and carotid artery
Neural Regulation of Respiration
- Medulla: Controls respiratory rate and depth.
- Pons: Appears to smooth out respiratory rate.
- Eupnea: Normal breathing patterns.
- Hyperpnea: Increased respiratory rate often due to extra oxygen needs.
Respiratory Volumes and Capacities
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Tidal volume (TV): Normal breathing, moves about 500 ml of air with each breath.
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Many factors affect respiratory capacity: gender, age, physical condition.
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Residual volume: After exhalation, about 1200 ml of air remains in the lungs.
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Inspiratory reserve volume (IRV): Amount of air that can be forcibly taken in over tidal volume. Usually between 2100 and 3200 ml.
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Expiratory reserve volume (ERV): Air that can be forcibly exhaled; approximately 1200 ml.
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Vital capacity: Total exchangeable air (TV + IRV + ERV).
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Dead space volume: Air remaining in conducting zone and that does not reach alveoli.
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Functional volume: Air that reaches the respiratory zone (usually about 350 ml).
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Respiratory capacities are measured with a spirometer.
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Description
Explore the essential functions and organs of the respiratory system in this quiz. From gas exchange to the roles of the nose, pharynx, larynx, trachea, and bronchi, test your knowledge on how we breathe. Perfect for biology students wanting to deepen their understanding of anatomy.
