The Respiratory System

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Questions and Answers

What is the primary function of the alveoli in the respiratory system?

To warm and humidify the air we breathe

To produce sound for speech

To facilitate the exchange of oxygen and carbon dioxide (correct)

To filter out dust and bacteria from the air

Which of the following muscles is responsible for separating the chest cavity from the abdominal cavity?

Intercostal muscles

Bronchi muscles

Laryngeal muscles

Diaphragm (correct)

What is the process by which oxygen diffuses from the air we breathe into the blood?

Passive transport

Osmosis

Active transport

Diffusion (correct)

Which part of the brain plays a role in consciously controlling breathing?

Cerebral cortex Signup and view all the answers

What is the function of the bronchi in the respiratory system?

To branch off from the trachea and lead to the lungs Signup and view all the answers

What is the purpose of the pharynx in the respiratory system?

To allow air to pass through Signup and view all the answers

What is the role of the intercostal muscles in breathing?

To expand and contract the chest cavity Signup and view all the answers

What is the primary function of the larynx in the respiratory system?

To produce sound for speech Signup and view all the answers

What is the primary function of the nasal conchae?

To increase surface area for warming and humidifying air Signup and view all the answers

What is the primary function of the olfactory epithelium?

To contain receptors for the sense of smell Signup and view all the answers

What is the primary function of the cricoid cartilage?

To support the larynx Signup and view all the answers

What is the primary function of the thyroid cartilage?

To form the Adam's apple Signup and view all the answers

What is the primary function of the true vocal cords?

To produce sound vibrations as air passes through Signup and view all the answers

What is the primary function of the trachea?

To conduct air to the bronchi Signup and view all the answers

What is the primary function of the C rings in the trachea?

To allow the trachea to expand and contract during breathing and swallowing Signup and view all the answers

What is the primary function of the uvula?

To prevent food from entering the nasal cavity during swallowing Signup and view all the answers

What is the primary function of the epiglottis?

To cover the glottis during swallowing to prevent food from entering the airway Signup and view all the answers

What is the primary function of the right lung?

To have three lobes (superior, middle, and inferior) Signup and view all the answers

Which of the following is responsible for reducing surface tension in the alveoli?

Type II Pneumocytes Signup and view all the answers

What is the term for the maximum amount of air exhaled after a maximal inhalation?

Vital Capacity Signup and view all the answers

Which of the following is NOT a mechanism of carbon dioxide transport?

Attached to red blood cell membranes Signup and view all the answers

What is the normal respiratory rate for an adult?

12-20 breaths per minute Signup and view all the answers

What is the term for the movement of air into and out of the lungs?

Ventilation Signup and view all the answers

Which of the following is responsible for separating the chest cavity from the abdominal cavity?

Diaphragm Signup and view all the answers

What is the term for the absence of breathing?

Apnea Signup and view all the answers

Which of the following is the most important chemical regulator of respiration?

Carbon dioxide (CO₂) Signup and view all the answers

What is the instrument used to measure respiratory volumes?

Spirometer Signup and view all the answers

Which part of the brain is responsible for regulating breathing?

Medulla oblongata and pons Signup and view all the answers

What is the primary function of the visceral pleura?

Covers the lungs Signup and view all the answers

Which of the following respiratory volumes is the amount of air remaining in the lungs after a forced exhalation?

Residual Volume Signup and view all the answers

What is the rate of breathing in a normal adult?

12-20 breaths per minute Signup and view all the answers

Which of the following is responsible for separating the chest cavity from the abdominal cavity?

Diaphragm Signup and view all the answers

What is the term for the absence of breathing?

Apnea Signup and view all the answers

What is the mechanism of quiet exhalation?

Passive process; diaphragm and intercostal muscles relax Signup and view all the answers

Which of the following is NOT a mechanism of carbon dioxide transport?

As oxygen bound to hemoglobin Signup and view all the answers

What is the primary function of the parietal pleura?

Lines the thoracic cavity Signup and view all the answers

Which of the following muscles is responsible for quiet inhalation?

Diaphragm and external intercostal muscles Signup and view all the answers

What is the location of the respiratory center in the brain?

Medulla oblongata and pons Signup and view all the answers

What is the primary function of the nasal cavity?

To warm, moisten, and filter incoming air Signup and view all the answers

Which structure connects the larynx and trachea to the esophagus?

Laryngopharynx Signup and view all the answers

What is the purpose of the C-shaped cartilage rings in the trachea?

To prevent collapse of the trachea Signup and view all the answers

Which part of the respiratory system consists of the nose, nasal cavity, paranasal sinuses, and pharynx?

Upper Respiratory Tract Signup and view all the answers

What is the correct pathway of air during inspiration?

Nose/Mouth → Pharynx → Larynx → Trachea → Primary Bronchi → Secondary Bronchi → Tertiary Bronchi → Bronchioles → Alveoli Signup and view all the answers

What is the primary function of the olfactory epithelium?

To contain receptors for the sense of smell Signup and view all the answers

How many lobes does the right lung have?

3 Signup and view all the answers

What is the function of the bronchioles?

To control airflow resistance and distribution of air Signup and view all the answers

What is the function of the glottis?

To open and close the airway during breathing Signup and view all the answers

What is the purpose of the auditory tube?

To equalize pressure between the middle ear and nasopharynx Signup and view all the answers

Match the following terms with their definitions:

External Respiration = Gas exchange between the lungs and blood. Internal Respiration = Gas exchange between blood and body tissues. Ventilation = Movement of air into and out of the lungs. Respiratory Center = Location in the brainstem that regulates breathing. Signup and view all the answers

Match the following respiratory volumes with their descriptions:

Tidal Volume = Volume of air moved in and out during a normal breath. Vital Capacity = Maximum amount of air exhaled after a maximal inhalation. Residual Volume = Amount of air remaining in the lungs after a forced exhalation. Inspiratory Reserve Volume = Maximum amount of air inhaled after a normal tidal volume. Signup and view all the answers

Match the following terms with their functions:

Diaphragm = Primary muscle of quiet inhalation. Intercostal Muscles = Accessory muscles of quiet inhalation. Parietal Pleura = Lines the thoracic cavity. Visceral Pleura = Covers the lungs. Signup and view all the answers

Match the following terms with their descriptions:

Apnea = Absence of breathing. Dyspnea = Difficult or labored breathing. Eupnea = Normal, quiet breathing. Hyperpnea = Increased depth and rate of breathing. Signup and view all the answers

Match the following terms with their functions:

Type I Pneumocytes = Thin cells for gas exchange in the alveoli. Type II Pneumocytes = Produce surfactant to reduce surface tension in the alveoli. Pleura = Reduces friction and allows smooth movement of the lungs during breathing. Spirometer = Instrument used to measure respiratory volumes. Signup and view all the answers

Match the following terms with their descriptions:

Medulla Oblongata = Location of the respiratory center in the brain. Pons = Part of the brain involved in regulating breathing. Hemoglobin = Protein in red blood cells that binds to oxygen. Carbaminohemoglobin = Form of hemoglobin bound to carbon dioxide. Signup and view all the answers

Match the following terms with their functions:

Surfactant = Prevents alveoli from collapsing by reducing surface tension. Oxygen = Bind to hemoglobin in red blood cells. Carbon Dioxide = Regulator of respiration. Diaphragm = Muscle of quiet inhalation. Signup and view all the answers

Match the following terms with their descriptions:

Inhalation = Drawing air into the lungs. Exhalation = Expelling air from the lungs. Respiratory Rate = Number of breaths per minute. Left Lung = Has two lobes, including the cardiac notch. Signup and view all the answers

Match the following terms with their functions:

Parietal Pleura = Lines the thoracic cavity. Visceral Pleura = Covers the lungs. Serous Membrane = Reduces friction and allows smooth movement of the lungs during breathing. Lung = Site of gas exchange in the respiratory system. Signup and view all the answers

Match the following structures of the respiratory system with their functions:

Nasal Cavity = Warms, moistens, and filters incoming air. Auditory Tube (Eustachian Tube) = Equalizes pressure between the middle ear and nasopharynx. Thyroid Cartilage = Forms the Adam's apple; protects the vocal cords. Cricoid Cartilage = Provides support to the larynx. Signup and view all the answers

Match the following components of the respiratory system with their descriptions:

Upper Respiratory Tract = Nose, nasal cavity, paranasal sinuses, pharynx. Lower Respiratory Tract = Larynx, trachea, bronchi, bronchioles, lungs. Primary Bronchi = Branch from the trachea into the lungs; right and left primary bronchi. Bronchioles = Smaller branches of the bronchi; control airflow resistance and distribution of air. Signup and view all the answers

Match the following structures with their functions in the respiratory system:

True Vocal Cords/Folds = Produce sound by vibrating as air passes through. Trachea = Windpipe; conducts air to the bronchi; supported by C-shaped cartilage rings. C Rings = Prevent collapse of the trachea while allowing flexibility. Glottis = Opening between the vocal cords. Signup and view all the answers

Match the following components of the respiratory system with their functions:

Oropharynx = Passageway for air and food; contains the palatine and lingual tonsils. Laryngopharynx = Passageway for air and food; connects to the esophagus and larynx. Epiglottis = Covers the glottis during swallowing to prevent food from entering the airway. Uvula = Prevents food from entering the nasal cavity during swallowing. Signup and view all the answers

Match the following components of the respiratory system with their locations:

Alveoli = Site of gas exchange in the lungs. Nasopharynx = Air passageway; houses the pharyngeal tonsils. Olfactory Epithelium = Contains receptors for the sense of smell in the nasal cavity. Nasal Conchae = Increase surface area for warming and humidifying air in the nasal cavity. Signup and view all the answers

Match the following components of the respiratory system with their functions:

Bronchi = Branch into smaller bronchioles; control airflow resistance and distribution of air. Bronchioles = Smaller branches of the bronchi; control airflow resistance and distribution of air. Larynx = Produces sound through the vocal cords. Trachea = Conducts air to the bronchi; supported by C-shaped cartilage rings. Signup and view all the answers

Match the following components of the respiratory system with their features:

Right Lung = Has 3 lobes (superior, middle, inferior). Cricoid Cartilage = Provides support to the larynx. Thyroid Cartilage = Forms the Adam's apple; protects the vocal cords. Trachea = Has C-shaped cartilage rings preventing collapse during breathing and swallowing. Signup and view all the answers

Match the following components of the respiratory system with their functions:

Nasopharynx = Air passageway; houses the pharyngeal tonsils. Oropharynx = Passageway for air and food; contains the palatine and lingual tonsils. Laryngopharynx = Passageway for air and food; connects to the esophagus and larynx. Auditory Tube (Eustachian Tube) = Equalizes pressure between the middle ear and nasopharynx. Signup and view all the answers

Match the following components of the respiratory system with their functions:

Nasal Cavity = Warms, moistens, and filters incoming air. Nasal Conchae = Increase surface area for warming and humidifying air. Olfactory Epithelium = Contains receptors for the sense of smell. Pharynx = Passageway for air and food; divided into nasopharynx, oropharynx, and laryngopharynx. Signup and view all the answers

Match the following components of the respiratory system with their descriptions:

C Rings = Prevent collapse of the trachea while allowing flexibility during breathing and swallowing. Epiglottis = Covers the glottis during swallowing to prevent food from entering the airway. Glottis = Opening between the vocal cords. Uvula = Prevents food from entering the nasal cavity during swallowing. Signup and view all the answers

Study Notes

Respiratory System

Functions:

Bring oxygen into the body
Remove carbon dioxide from the body
Regulate pH levels by removing excess hydrogen ions

Organs:

Nose and mouth: air enters the body
Pharynx: air passes through
Larynx: contains vocal cords, air passes through
Trachea: air tube that leads to lungs
Bronchi: air tubes that branch off from trachea
Bronchioles: smaller air tubes that branch off from bronchi
Alveoli: tiny air sacs where gas exchange occurs
Lungs: organs that contain alveoli
Diaphragm: muscle that separates chest cavity from abdominal cavity
Intercostal muscles: muscles between ribs that aid in breathing

Mechanism of Breathing:

Inhalation:
- Diaphragm contracts and flattens
- Intercostal muscles contract and ribs move outward
- Air enters through nose or mouth, passes through pharynx and larynx
- Air enters trachea and bronchi, and then bronchioles
- Air reaches alveoli and oxygen diffuses into blood
Exhalation:
- Diaphragm relaxes and rises
- Intercostal muscles relax and ribs move inward
- Air is pushed out of alveoli and into bronchioles
- Air passes through bronchi, trachea, pharynx, and larynx
- Air exits through nose or mouth

Gas Exchange:

Oxygen diffuses from alveoli into blood
Carbon dioxide diffuses from blood into alveoli
Oxygen binds to hemoglobin in red blood cells
Carbon dioxide is transported to lungs and exhaled out of body

Control of Breathing:

Brainstem: regulates automatic breathing
Pons: helps regulate breathing rate
Medulla oblongata: helps regulate breathing rate
Cerebral cortex: can consciously control breathing
Feedback mechanisms: sensors in body monitor oxygen and carbon dioxide levels, sending signals to brain to adjust breathing rate

Respiratory System

The respiratory system's main functions are to bring oxygen into the body, remove carbon dioxide, and regulate pH levels by removing excess hydrogen ions

Organs

Air enters the body through the nose and mouth
The pharynx is the passage air goes through after entering the nose or mouth
The larynx contains vocal cords and air passes through it
The trachea is the air tube that leads to the lungs
Bronchi are air tubes that branch off from the trachea
Bronchioles are smaller air tubes that branch off from bronchi
Alveoli are tiny air sacs where gas exchange occurs
Lungs are organs that contain alveoli
The diaphragm is the muscle that separates the chest cavity from the abdominal cavity
Intercostal muscles are the muscles between the ribs that aid in breathing

Mechanism of Breathing

During inhalation, the diaphragm contracts and flattens, and the intercostal muscles contract and the ribs move outward
During exhalation, the diaphragm relaxes and rises, and the intercostal muscles relax and the ribs move inward
Air enters through the nose or mouth, passes through the pharynx and larynx, and then enters the trachea and bronchi
Air then enters the bronchioles and reaches the alveoli where oxygen diffuses into the blood
During exhalation, air is pushed out of the alveoli and into the bronchioles, and then passes through the bronchi, trachea, pharynx, and larynx before exiting through the nose or mouth

Gas Exchange

Oxygen diffuses from the alveoli into the blood
Carbon dioxide diffuses from the blood into the alveoli
Oxygen binds to hemoglobin in red blood cells
Carbon dioxide is transported to the lungs and exhaled out of the body

Control of Breathing

The brainstem regulates automatic breathing
The pons helps regulate breathing rate
The medulla oblongata helps regulate breathing rate
The cerebral cortex can consciously control breathing
Feedback mechanisms involving sensors in the body monitor oxygen and carbon dioxide levels, sending signals to the brain to adjust breathing rate

Organs and Functions of the Respiratory System

Nasal cavity warms, moistens, and filters incoming air
Nasal conchae increase surface area for warming and humidifying air
Auditory tube (Eustachian tube) equalizes pressure between the middle ear and nasopharynx
Olfactory epithelium contains receptors for the sense of smell
Nasopharynx serves as an air passageway and houses pharyngeal tonsils
Oropharynx is a passageway for air and food, containing palatine and lingual tonsils
Laryngopharynx is a passageway for air and food, connecting to the esophagus and larynx
Primary bronchi branch from the trachea into the lungs (right and left primary bronchi)
Bronchioles are smaller branches of the bronchi, controlling airflow resistance and air distribution
Thyroid cartilage forms the Adam's apple, protecting the vocal cords
Cricoid cartilage provides support to the larynx
True vocal cords/folds produce sound by vibrating as air passes through
Trachea (windpipe) conducts air to the bronchi, supported by C-shaped cartilage rings
C rings prevent tracheal collapse while allowing flexibility
Uvula prevents food from entering the nasal cavity during swallowing
Epiglottis covers the glottis during swallowing, preventing food from entering the airway
Glottis is the opening between the vocal cords

Gas Exchange

Takes place in the alveoli of the lungs

C Rings in Trachea

The open posterior part allows the trachea to expand and contract during breathing and swallowing without collapsing

Upper and Lower Respiratory Tracts

Upper Respiratory Tract: nose, nasal cavity, paranasal sinuses, pharynx
Lower Respiratory Tract: larynx, trachea, bronchi, bronchioles, lungs

Order of Respiratory Structures During Inspiration

Pathway: nose/mouth → pharynx → larynx → trachea → primary bronchi → secondary bronchi → tertiary bronchi → bronchioles → alveoli

Lung Lobes and Cardiac Notch

Right Lung: 3 lobes (superior, middle, inferior)
Left Lung: 2 lobes (superior, inferior), containing the cardiac notch

Serous Membrane of the Lung

Name: Pleura
Layers:
- Parietal Pleura: lines the thoracic cavity
- Visceral Pleura: covers the lungs
Function: reduces friction and allows smooth movement of the lungs during breathing

Function of Cells in Alveoli

Type I Pneumocytes: thin cells for gas exchange
Type II Pneumocytes: produce surfactant to reduce surface tension

Importance of Surfactant

Prevents alveoli from collapsing by reducing surface tension

Definitions

External Respiration: gas exchange between the lungs and blood
Internal Respiration: gas exchange between blood and body tissues
Ventilation: movement of air into and out of the lungs
Inhalation: drawing air into the lungs
Exhalation: expelling air from the lungs

Respiratory Volumes

Tidal Volume: volume of air moved in and out during a normal breath
Vital Capacity: maximum amount of air exhaled after a maximal inhalation
Residual Volume: amount of air remaining in the lungs after a forced exhalation

Instrument for Measuring Respiratory Volumes

Name: Spirometer

Oxygen Transport

Mechanism: oxygen binds to hemoglobin in red blood cells and is transported to tissues

Carbon Dioxide Transport

Mechanisms:
- Dissolved in plasma
- Bound to hemoglobin as carbaminohemoglobin
- As bicarbonate ions (HCO₃⁻) in plasma

Normal Adult Respiratory Rate

Rate: 12-20 breaths per minute

Most Important Chemical Regulator of Respiration

Regulator: carbon dioxide (CO₂) levels

Muscles of Quiet Inhalation

Muscles: diaphragm and external intercostal muscles
Mechanism: diaphragm contracts (flattens) and external intercostals lift the ribcage, reducing pressure in the thoracic cavity and allowing air to flow in

Normal Quiet Exhalation

Mechanism: passive process; diaphragm and intercostal muscles relax, increasing thoracic pressure and forcing air out

Respiratory Center in the Brain

Location: medulla oblongata and pons

Definitions

Apnea: absence of breathing
Dyspnea: difficult or labored breathing
Eupnea: normal, quiet breathing
Hyperpnea: increased depth and rate of breathing

Organs and Functions of the Respiratory System

Nasal cavity warms, moistens, and filters incoming air
Nasal conchae increase surface area for warming and humidifying air
Auditory tube (Eustachian tube) equalizes pressure between the middle ear and nasopharynx
Olfactory epithelium contains receptors for the sense of smell
Nasopharynx serves as an air passageway and houses pharyngeal tonsils
Oropharynx is a passageway for air and food, containing palatine and lingual tonsils
Laryngopharynx is a passageway for air and food, connecting to the esophagus and larynx
Primary bronchi branch from the trachea into the lungs (right and left primary bronchi)
Bronchioles are smaller branches of the bronchi, controlling airflow resistance and air distribution
Thyroid cartilage forms the Adam's apple, protecting the vocal cords
Cricoid cartilage provides support to the larynx
True vocal cords/folds produce sound by vibrating as air passes through
Trachea (windpipe) conducts air to the bronchi, supported by C-shaped cartilage rings
C rings prevent tracheal collapse while allowing flexibility
Uvula prevents food from entering the nasal cavity during swallowing
Epiglottis covers the glottis during swallowing, preventing food from entering the airway
Glottis is the opening between the vocal cords

Gas Exchange

Takes place in the alveoli of the lungs

C Rings in Trachea

The open posterior part allows the trachea to expand and contract during breathing and swallowing without collapsing

Upper and Lower Respiratory Tracts

Upper Respiratory Tract: nose, nasal cavity, paranasal sinuses, pharynx
Lower Respiratory Tract: larynx, trachea, bronchi, bronchioles, lungs

Order of Respiratory Structures During Inspiration

Pathway: nose/mouth → pharynx → larynx → trachea → primary bronchi → secondary bronchi → tertiary bronchi → bronchioles → alveoli

Lung Lobes and Cardiac Notch

Right Lung: 3 lobes (superior, middle, inferior)
Left Lung: 2 lobes (superior, inferior), containing the cardiac notch

Serous Membrane of the Lung

Name: Pleura
Layers:
- Parietal Pleura: lines the thoracic cavity
- Visceral Pleura: covers the lungs
Function: reduces friction and allows smooth movement of the lungs during breathing

Function of Cells in Alveoli

Type I Pneumocytes: thin cells for gas exchange
Type II Pneumocytes: produce surfactant to reduce surface tension

Importance of Surfactant

Prevents alveoli from collapsing by reducing surface tension

Definitions

External Respiration: gas exchange between the lungs and blood
Internal Respiration: gas exchange between blood and body tissues
Ventilation: movement of air into and out of the lungs
Inhalation: drawing air into the lungs
Exhalation: expelling air from the lungs

Respiratory Volumes

Tidal Volume: volume of air moved in and out during a normal breath
Vital Capacity: maximum amount of air exhaled after a maximal inhalation
Residual Volume: amount of air remaining in the lungs after a forced exhalation

Instrument for Measuring Respiratory Volumes

Name: Spirometer

Oxygen Transport

Mechanism: oxygen binds to hemoglobin in red blood cells and is transported to tissues

Carbon Dioxide Transport

Mechanisms:
- Dissolved in plasma
- Bound to hemoglobin as carbaminohemoglobin
- As bicarbonate ions (HCO₃⁻) in plasma

Normal Adult Respiratory Rate

Rate: 12-20 breaths per minute

Most Important Chemical Regulator of Respiration

Regulator: carbon dioxide (CO₂) levels

Muscles of Quiet Inhalation

Muscles: diaphragm and external intercostal muscles
Mechanism: diaphragm contracts (flattens) and external intercostals lift the ribcage, reducing pressure in the thoracic cavity and allowing air to flow in

Normal Quiet Exhalation

Mechanism: passive process; diaphragm and intercostal muscles relax, increasing thoracic pressure and forcing air out

Respiratory Center in the Brain

Location: medulla oblongata and pons

Definitions

Apnea: absence of breathing
Dyspnea: difficult or labored breathing
Eupnea: normal, quiet breathing
Hyperpnea: increased depth and rate of breathing

Organs and Functions of the Respiratory System

Nasal cavity warms, moistens, and filters incoming air
Nasal conchae increase surface area for warming and humidifying air
Auditory tube (Eustachian tube) equalizes pressure between the middle ear and nasopharynx
Olfactory epithelium contains receptors for the sense of smell
Nasopharynx is an air passageway and houses the pharyngeal tonsils
Oropharynx is a passageway for air and food, and contains the palatine and lingual tonsils
Laryngopharynx is a passageway for air and food, and connects to the esophagus and larynx
Primary bronchi branch from the trachea into the lungs, with right and left primary bronchi
Bronchioles are smaller branches of the bronchi, controlling airflow resistance and distribution of air
Thyroid cartilage forms the Adam's apple and protects the vocal cords
Cricoid cartilage provides support to the larynx
True vocal cords/folds produce sound by vibrating as air passes through
Trachea is the windpipe, conducting air to the bronchi, and is supported by C-shaped cartilage rings
C rings prevent collapse of the trachea while allowing flexibility
Uvula prevents food from entering the nasal cavity during swallowing
Epiglottis covers the glottis during swallowing to prevent food from entering the airway
Glottis is the opening between the vocal cords

Gas Exchange

Gas exchange occurs in the alveoli of the lungs

C Rings in Trachea

The open posterior part of the C rings allows the trachea to expand and contract during breathing and swallowing without collapsing

Upper and Lower Respiratory Tracts

Upper respiratory tract includes the nose, nasal cavity, paranasal sinuses, and pharynx
Lower respiratory tract includes the larynx, trachea, bronchi, bronchioles, and lungs

Order of Respiratory Structures During Inspiration

Pathway: nose/mouth → pharynx → larynx → trachea → primary bronchi → secondary bronchi → tertiary bronchi → bronchioles → alveoli

Lung Lobes and Cardiac Notch

Right lung has 3 lobes (superior, middle, inferior)
Left lung has 2 lobes (superior, inferior) and contains the cardiac notch

Serous Membrane of the Lung

The pleura consists of two layers: parietal pleura lining the thoracic cavity, and visceral pleura covering the lungs
Function: reduces friction and allows smooth movement of the lungs during breathing

Functions of Cells in Alveoli

Type I pneumocytes are thin cells for gas exchange
Type II pneumocytes produce surfactant to reduce surface tension

Importance of Surfactant

Prevents alveoli from collapsing by reducing surface tension

Definitions

External respiration: gas exchange between the lungs and blood
Internal respiration: gas exchange between blood and body tissues
Ventilation: movement of air into and out of the lungs
Inhalation: drawing air into the lungs
Exhalation: expelling air from the lungs

Respiratory Volumes

Tidal volume: volume of air moved in and out during a normal breath
Vital capacity: maximum amount of air exhaled after a maximal inhalation
Residual volume: amount of air remaining in the lungs after a forced exhalation

Instrument for Measuring Respiratory Volumes

Spirometer

Oxygen and Carbon Dioxide Transport

Oxygen binds to hemoglobin in red blood cells and is transported to tissues
Carbon dioxide is transported through:
- Dissolved in plasma
- Bound to hemoglobin as carbaminohemoglobin
- As bicarbonate ions (HCO₃⁻) in plasma

Normal Adult Respiratory Rate

12-20 breaths per minute

Most Important Chemical Regulator of Respiration

Carbon dioxide (CO₂) levels

Muscles of Quiet Inhalation

Diaphragm and external intercostal muscles
Mechanism: diaphragm contracts (flattens) and external intercostals lift the ribcage, reducing pressure in the thoracic cavity and allowing air to flow in

Normal Quiet Exhalation

Mechanism: passive process; diaphragm and intercostal muscles relax, increasing thoracic pressure and forcing air out

Respiratory Center in the Brain

Located in the medulla oblongata and pons

Additional Definitions

Apnea: absence of breathing
Dyspnea: difficult or labored breathing
Eupnea: normal, quiet breathing
Hyperpnea: increased depth and rate of breathing

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Description

Learn about the functions and organs of the respiratory system, including bringing oxygen into the body, removing carbon dioxide, and regulating pH levels.