Ch 6. Respiratory System Flashcards
OVERVIEW OF THE RESPIRATORY SYSTEM
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Which organs are in the respiratory system?
Nose. Pharynx. Larynx. Trachea. Primary (or main) Bronchi. Lung The Mouth (can ONLY be apart of the respiratory system if you're breathing with your mouth - usually when you're sick and your nose is clogged)
What is the function/purpose of the respiratory system?
To bring Oxygen into the body and take Carbon Dioxide out. This function allows cellular respiration to occur.
What is cellular respiration?
Cellular Respiration, AKA Aerobic Respiration, is the process by which a cell breaks down a nutrient (such as glucose) to produce large amounts of energy in the form of ATP.
What is the reaction for cellular respiration?
The nutrient molecule (such as glucose). Plus oxygen. Yields carbon dioxide. Plus water. Plus ATP.
How does the respiratory system use inhalation to bring in oxygen that is needed for cellular respiration?
- Oxygen enters the body when you inhale
- Oxygen then diffuses in the blood
- Blood transports the oxygen to the cells of the body
- The body cells, in turn, use the oxygen along with the nutrient molecule for cellular respiration
NOTE: The nutrient molecule broken down for cellular respiration is provided to body cells from the Digestive System!
How does the body get rid of carbon dioxide through exhalation, since it is toxic to cells?
Once carbon dioxide is produced by body cells via cellular respiration, carbon dioxide diffuses into the bloodstream. From the bloodstream, carbon dioxide is transported to the lungs. The carbon dioxide is then removed from the body when you exhale.
Why is the respiratory system important?
The respiratory system is important because it brings in the oxygen needed for cellular respiration to take place and it gets rid of the carbon dioxide that is produced as a waste product of cellular respiration.
Two branches of medicine associated with the respiratory system?
Otorhinolaryngology and Pulmonology.
- Otorhinolaryngology is the study of the structure, function, and disorders of the EARS, NOSE, and THROAT.
- Pulmonology is the study of the structure, function, and disorders of the LUNGS.
RESPIRATORY MUCOSA
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What is the respiratory tract lined with?
The respiratory tract is lined by a mucosa. This means that the part of the wall of the respiratory organs that is closest to lumen consists of a mucosa.
What is a mucosa?
A mucosa, AKA a mucous membrane, consists of a layer of the epithelial cells and an underlying layer of connective tissue. The epithelium contains ciliated cells and goblet cells that secrete mucus. Mucus is a sticky secretion that traps inhaled particles.
- The epithelium contains ciliated cells and goblet cells that secrete mucus
What does cilia do? What is the goal?
The goal of the cilia is to move the mucus toward the pharynx, where the mucus is swallowed, then enters into the esophagus (which is a digestive organ),and is subsequently brought down by gastric juice in the stomach
Which direction does the cilia move mucus towards the pharynx to be swallowed?
- Because the Nose is above the pharynx, the cilia in the nose move the mucus in a DOWNWARD direction toward the pharynx to be swallowed.
- Because the Larynx. Trachea. Primary bronchi. Bronchial tubes of the lungs. Are all below the pharynx. The cilia in these areas move the mucus in an UPWARD direction toward the pharynx to be swallowed
Define Mucociliary Escalator
The term Mucociliary escalator refers to the movement of mucus along the respiratory tract toward the pharynx to be swallowed.
NOSE
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Where does the respiratory system begin?
The nose
What are the two major regions of the nose?
External Nose & Nasal Cavity
- The external nose consists of bone and cartilage covered by skin.
- The nasal cavity is the space within the nose.
Details of the nasal cavity:
- The nasal cavity is surrounded by bones that are lined by a mucosa.
- The epithelium of the mucosa consists of ciliated cells and scattered goblet cells that secrete mucus.
- The anterior region of the nasal cavity opens up to the outside environment as the external nares (or nostrils).
- The singular form is external naris or nostril.
- The posterior region of the nasal cavity joins the pharynx.
- The superior region of the nasal cavity contains the olfactory epithelium.
- The olfactory epithelium consists of sensory receptors that are involved in the detection of smell.
What are the functions of the nose?
- A major function of the nose is to FILTER, WARM, and HUMIDIFY incoming air.
- Another function of the nose is to DETECT OLFACTORY STIMULI.
- The nose also MODIFIES SPEECH VIBRATIONS as they pass through the sinuses, which are large, hollow resonating chambers of the head.
POWERPHYS ACTIVITY
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What can be used to monitor air flow in the respiratory system?
A Spirograph
What is the Tidal Volume & Breathing Rate of resting adults?
- Tidal Volume, TV: Resting adults inhale and exhale 500 mL of air on average with each breath
- Breathing Rate, BR: Resting adults breathe about 12 times per minute
How do you measure Minute Ventilation?
The product of tidal volume and breathing rate indicates the amount of air that moves into and out of the lungs each minute (minute ventilation, MV = TV × BR)
- Minute ventilation INCREASES when the body is using more oxygen and producing more carbon dioxide, as occurs in exercising.
What’s a Spirometer? What’s a Spirogram?
- A Spirometer is an instrument used to measure lung volumes and capacities.
- The record resulting from the tests is called a Spirogram. The spirometer used in this experiment measures both inspiratory and expiratory volumes.
What are the Lung Volumes in Healthy Adults?
Lung Volumes of a Healthy Adult:
Tidal Volume (TV) — Tidal volume is the amount of air inhaled or exhaled in one breath. Resting tidal volume is normally about 500 milliliters.
Inspiratory reserve volume (IRV) — Volume of air that can be forcibly inhaled after normal, quiet inhalation (about 3100 mL or 3.1L)
Expiratory reserve volume (ERV) — Volume of air that can be forcibly exhaled after normal, quiet exhalation (about 1200mL or 1.2L)
Residual volume (RV) — Volume of air that remains in the lungs after a maximal exhalation (about 1200mL or 1.2L)
*** Residual Volume (females 19-99 yrs)
RV = (0.0813 × height in inches) + (0.009 × age in yrs.) – 3.9
Note: All studied subjects are females 25 years old and 65 inches tall
What are the Lung Capacities of a Healthy Adult?
Lung capacities can be calculated by adding two or more lung volumes.
Inspiratory capacity (IC) = TV + IRV = about 3600 mL or 3.6L
Functional residual capacity (FRC) = ERV + RV = about 2400 mL or 2.4L
Vital capacity (VC) = TV + IRV + ERV = about 4800mL or 4.8L
Total lung capacity (TLC) = TV + IRV + ERV + RV = about 6000 mL or 6L
Minute Ventilation
Multiply the breathing rate (breaths/min) by tidal volume.
PRE LAB QUESTIONS:
.
The volume of air remaining in lungs after normal expiration is the:
Functional Residual Capacity
The maximum amount of air that can be exhaled after a normal expiration is the:
Expiratory Reserve Volume
Lung volumes are measured:
FOR ALL REASONS LISTED BELOW:
- to examine if pulmonary functions are improving
- to observe if pulmonary functions are deteriorating
- for diagnosis of respiratory disease
The lung volume or capacity that is equal to IC - IRV is the:
Tidal Volume
The value for this volume is about 500 mL:
Tidal Volume
If you breathe in as deeply as you can and then exhale as deeply as possible, which lung capacity have you demonstrated?
Vital Capacity
The lung volume or capacity that is equal to IC - TV is the:
Inspiratory Reserve Volume
The lung volume or capacity that is equal to FRC - ERV is the:
Residual Volume
BACK TO POWERPHYS ACTIVITY
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Dependent Variable
Respiratory Volumes
Independent Variable
Level of Physical Activity [resting or exercising]
Controlled Variables
Sex
Age
Height
QUESTION SET 8 QUESTIONS:
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In this experiment, the breathing rate after exercise:
increased approximately 150%
In this experiment, the tidal volume after exercise:
increased approximately 220%
In this experiment, the expiratory reserve volume after exercise:
decreased approximately 60%
In this experiment, inspiratory reserve volume after exercise:
decreased approximately 17%
In this experiment, residual volume after exercise:
stayed the same, did not change
In this experiment, which of the following lung capacities showed the increase with exercise?
IC
In this experiment, minute ventilation after exercise
Increased by approximately 680%
THE PHARYNX
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What is the pharynx?
The pharynx, aka throat, is what connects your nasal cavity with the larynx and esophagus
What two systems do the pharynx belong to?
The Digestive and Respiratory system
What 3 regions are in the pharynx?
Nasopharynx, Oropharynx and Laryngopharynx
Nasopharynx - The upper portion of the pharynx that is continuous with the nasal cavity.
Oropharynx - The portion of the pharynx that is continuous with the oral cavity.
Laryngopharynx - The portion of the pharynx that is continuous with the larynx anteriorly and the esophagus inferiorly.
What two layers does the wall of the pharynx consist of?
Skeletal muscle and Mucosa.
- Skeletal muscle forms the outer layer of the pharynx.
- Mucosa forms the inner layer that lines the lumen of the pharynx.
What does the epithelium of the mucosa consist of?
What is the function of the pharynx?
- Ciliated Cells and Scattered Goblet Cells that secrete mucus.
- In terms of function, the pharynx serves as a passageway for air and food and acts as a resonating chamber for speech sounds.
THE LARYNX
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What is the larynx?
The larynx, aka voice box, is a passageway that connects the pharynx with the trachea.
What does the larynx consist of?
- Cartilage, Skeletal Muscle, and Mucosa
- Several pieces of cartilage form the outer layer of the larynx.
- The skeletal muscle forms the middle layer of the larynx.
- The mucosa forms the inner layer of the larynx closest to the lumen.
What are the important laryngeal cartilages?
Thyroid Cartilage, Cricoid Cartilage, and Epiglottis
- The Thyroid Cartilage, aka adam’s apple, forms the anterior wall of the larynx. It is usually larger in males than in the females because testosterone stimulates its growth during puberty.
- The Cricoid Cartilage is a ring of cartilage that is inferior to the thyroid cartilage.
- The Epiglottis is a spoon-shaped piece of cartilage that is attached to the thyroid cartilage at one end, while the other end is free to move up and down. The epiglottis allows air, but not food or liquid, to enter into the rest of the respiratory tract.
How does the Epiglottis allow air into the respiratory tract, but not food or liquid?
- When only AIR is moving into the nose and pharynx, the free end of the epiglottis is POINTING UPWARD and the larynx is open, allowing air to travel into the rest of the respiratory tract.
- During SWALLOWING, the free end of the epiglottis MOVES DOWN to COVER the larynx like a lid. This prevents food and liquids from entering the larynx, thereby forcing these substances into the esophagus.
What happens if anything other than air finds it’s way into the layrnx?
A vigorous coughing reflex will occur.
- This reflex is coordinated by the coughing center in the
medulla oblongata
What are the 2 pairs of folds (connective tissue strings) in the larynx?
- Superior pair of vestibular folds ( false vocal cords )^ these are called false vocal cords because they are
NOT involved in vocalization. - Inferior pair of vocal folds ( true vocal cords )
^ these are the only ones involved in vocalization, this is
why they’re called true vocal cords
Define Vocalization.
How does vocalization happen/what causes it?
What determines the volume of the sound?
What determines the pitch of the sound?
What causes men to have deeper voices than women?
- Vocalization is the production of sounds.
- When air strikes the vocal folds, the vocal folds vibrate
and sound is produced. - The loudness is determined by how vigorously air
strikes the vocal folds. When air strikes the vocal folds
forcefully, a loud sound is produced. When air strikes
the vocal folds mildly, a soft sound is produced. - The pitch is determined by the tautness (tightness) of
the vocal folds. Tight vocal folds produce a high-
pitched sound, whereas loose vocal folds produce a
low-pitched sound. - Testosterone
- When air strikes the vocal folds, the vocal folds vibrate
What gives the voice a more quality sound to it, when it starts off sounding artificial.
- The sounds produced by the larynx sound somewhat artificial, but as the sounds resonate or BOUNCES off of the PHARYNX and the sinuses of the head, the voice then takes on a richer, more natural QUALITY.
THE TRACHEA
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What/where is the trachea?
- The trachea, aka windpipe, is a tube that extends from
the larynx.
What does the trachea consist of?
- “C-shaped” Rings of Cartilage that form the outer
anterior and lateral walls.AND
- Smooth Muscle called the Trachealis muscle that forms
the outer posterior wall. Mucosa that lines the lumen.
- Smooth Muscle called the Trachealis muscle that forms
PURPOSES OF THESE THINGS:
- The Cartilages provide support to the trachea and
prevent it from collapsing. - Contraction or relaxation of the trachealis muscle
changes the diameter of the trachea, which alters
airflow. - The epithelium of the mucosa consists of ciliated cells
and scattered goblet cells that secrete mucus.
What is the purpose of the trachea?
To convey air from the larynx to the primary bronchi.
THE PRIMARY BRONCHI
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What are the two primary bronchi?
hint: the end of the trachea branches into two large
primary (or main) bronchi, a blank and a blank.
- Right primary (or main) bronchus, which goes to the
right lung.- Left primary (or main) bronchus, which goes to the left
lung.
- Left primary (or main) bronchus, which goes to the left
Where are the bronchi?
Outside of the lungs
What does the Primary Bronchi consist of?
- The wall of each primary bronchus is similar to that of the trachea: “C-shaped” rings of cartilage form the outer Anterior and Lateral walls, smooth muscle forms the outer posterior wall, and a mucosa lines the lumen.
- The epithelium of the mucosa consists of ciliated cells and scattered goblet cells that secrete mucus.
What is the purpose of the Primary Bronchi?
To convey air from the trachea to the smaller bronchi and bronchioles of the lungs.
THE LUNGS
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What/where is the lungs?
The lungs are cone-shaped organs located in the thoracic cavity
What surrounds the lungs?
What are the two layers of the pleura?
- A connective tissue sac called the Pleura.
The 2 layers of the pleura are the Parietal & Visceral
- Parietal layer, also known as the parietal pleura. The
parietal layer lines the wall of the thoracic cavity. - Visceral layer, also called the visceral pleura. The
visceral layer covers the lung itself.
What is between the two layers of the pleura?
- The pleural cavity. Which is also known as the
Intrapleural cavity or Intrapleural space. This space
contains a fluid called intrapleural fluid or pleural fluid.
How many lobes does the lungs have?
- The Right Lung has three lobes.
- The left lung has only two lobes in order to
accommodate the position of the heart.
- The left lung has only two lobes in order to
Nevertheless, the left lung is still roughly about the same size as the right lung.
Lung branches of a primary bronchus:
Note: Each lung consists of the branches of a primary bronchus. These branches become sequentially smaller and smaller.
- The secondary bronchi continue to branch to form
tertiary (or segmental) bronchi. The TERTIARY
BRONCHI divide many times, eventually giving rise to
bronchioles.- The tertiary bronchi divide many times, eventually
giving rise to BRONCHIOLES. - Bronchioles, in turn, branch to form TERMINAL
BRONCHIOLES. Although terminal bronchioles are
called terminal, there is nothing terminal about them.
The party has just gotten started. There are many more
branches to go! - The terminal bronchioles branch to
give rise to RESPIRATORY BRONCHIOLES. Respiratory bronchioles have a few alveoli that extend from their walls. - Respiratory bronchioles divide to give rise to ALVEOLAR DUCTS Alveolar ducts contain even more alveoli.
- The alveolar ducts give rise to ALVEOLAR SACS. Aveolar sacs contain large numbers of alveoli arranged in clusters. An alveolar sac is comparable to a bunch of grapes, with each grape being an alveolus.
- The tertiary bronchi divide many times, eventually
The lungs bronchi, bronchioles, and aveoli details:
The larger bronchi of the lungs (such as a secondary bronchus and a tertiary bronchus) consist of.
Outer layer of cartilage.
Middle layer of smooth muscle.
Inner layer of mucosa.
As the bronchi give rise to bronchioles, the cartilage disappears. In other words, a bronchiole consists of smooth muscle and a mucosa, but no cartilage. As the bronchioles give rise to alveoli, the smooth muscle disappears. So, an alveolus essentially only has a mucosa that comprises its wall.
By the time the bronchial tree has give rise to alveoli, structural components such as cartilage and smooth muscle are no longer present because they would impede gas exchange. In addition, the epithelium of the mucosa of the alveolus consists of thin, flat cells that lack cilia, and no mucus-secreting goblet cells are present. The presence of thin, flat cells and the lack of cilia and mucus also facilitate gas exchange in the alveolus.
AVEOLI - Recall that alveoli are present in the respiratory bronchioles, alveolar ducts, and alveolar sacs. The alveoli are the sites of gas exchange. An alveolus consists of little more than an epithelium supported by a basement membrane. In other words, the wall of the alveolus is essentially a thin mucosa. The cells of the alveolar epithelium are flat and lack cilia, and there are no mucus-secreting goblet cells. In addition, no smooth muscle and cartilage are present in the wall of the alveolus. If cilia, mucus, smooth muscle, and cartilage were present, they would all impede gas exchange. The epithelium of an alveolus consists of two types of cells.
TYPES OF CELLS IN THE AVEOLUS: Type I alveolar cells. Type II alveolar cells. Type I alveolar cells form a nearly continuous lining of the alveolar wall. They are the main sites of gas exchange. Type II alveolar cells, also known as septal cells, secrete alveolar fluid that contains surfactant. Surfactant is a mixture of lipids and proteins that lowers the surface tension of alveolar fluid, which reduces the tendency of alveoli to collapse. Associated with the alveolar epithelium are alveolar macrophages. These cells phagocytize debris and any microbes that may be present.
PULMONARY CAPILLARIES IN THE AVEOLI: Surrounding the alveoli is a network of pulmonary capillaries. During gas exchange, oxygen in inhaled air diffuses from the lumen of the alveolus across the wall of the alveolus into pulmonary capillary blood. And carbon dioxide diffuses from pulmonary capillary blood into the lumen of the alveolus to be exhaled. The wall of an alveolus and pulmonary capillary together form the respiratory membrane.
4 LAYERS OF THE RESPIRATORY MEMBRANE: Extending from the alveolar air to the blood, the respiratory membrane consists of four layers. (1) Alveolar epithelium. (2) Epithelial basement membrane. (3) Capillary basement membrane. (4) Capillary endothelium. Again, all four of these layers make up the respiratory membrane. One more time, these layers are as follows. (1) Alveolar epithelium. (2) Epithelial basement membrane. (3) Capillary basement membrane. (4) Capillary endothelium. All four of these layers make up the respiratory membrane. Despite having several layers, the respiratory membrane is very thin to allow rapid diffusion of gases.
THE AIRWAY
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Basic details about the airway
- The components of the respiratory system are
considered to be one continuous airway.- The components of the airway that are located outside
the lungs include the following: Nose. Pharynx. Larynx.
Trachea. Right and left primary bronchi. - The components of the airway that are within the lungs
Include the secondary bronchi all the way down to the
alveoli.
- The components of the airway that are located outside
What are the zones and functions of the airway?
- Two zones are:
CONDUCTION ZONE & RESPIRATORY ZONE. - The conducting zone Is the part of the airway from the
nose to the terminal bronchioles. Although in this
figure, it seems as if the conducting zone starts with the
trachea, realize that in actuality it starts with the nose.
The other parts of the conducting zone (in other words,
the nose, pharynx, and larynx) are not shown in this
figure in order to save space. Again, the conducting
zone is from the nose to the terminal bronchioles.THE FUNCTION of the CONDUCTION ZONE: to filter,
warm, and humidify air and also to conduct the air into
and out of the lungs. No gas exchange takes place in
the conducting zone because alveoli are not present.
The conducting zone also removes microbes and
debris from the respiratory tract. This occurs via the
mucociliary escalator. - The respiratory zone is the part of the airway that
contains alveoli. It includes the. Respiratory
bronchioles. Alveolar ducts. Alveolar sacs. The function
of the respiratory zone is to carry out gas exchange.
AUTONOMIC INNERVATION OF THE RESPIRATORY SYSTEM
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Smooth muscle in the walls of the bronchi details
- The smooth muscle in the walls of the bronchi and
many bronchioles of the lungs are innervated by both
divisions of the autonomic nervous system.- Parasympathetic nerves (via the vagus nerves) cause
the smooth muscle of the bronchi and bronchioles to
contract, resulting in bronchoconstriction. This means
that the lumen of the bronchial tube become more
narrow. - Sympathetic nerves cause the smooth muscle of the
bronchi and bronchioles to relax, resulting in
bronchodilation. This means that the lumen of the
bronchial tube become wider. During the
parasympathetic mode, the bronchi and bronchioles are
partially bronchoconstricted because not as much air is
needed. During the sympathetic mode, the bronchi and
bronchioles bronchodilate to bring more air into the
lungs.
- Parasympathetic nerves (via the vagus nerves) cause
THE BREATHING CYCLE:
.
What is breathing?
The mechanical flow of air in and out of the lungs
What are the 3 pressures that are important to the process of breathing?
ATMOSPHERIC PRESSURE. ALVEOLAR PRESSURE. INTRAPLEURAL PRESSURE.
- Atmospheric pressure: the pressure of the air in the
atmosphere, which at sea level is about 760 mmHg or 1
atmosphere. - Alveolar pressure: the pressure of air within the alveoli
of the lungs. Depending on the stage of the breathing
cycle, alveolar pressure may be lower or equal to or
higher than atmpospheric pressure. - Intrapleural pressure: the pressure within the pleural cavity. Each lung is surrounded by a pleura. This pressure comes from intrapleural fluid. This pressure is ALWAYS LOWER than atmospheric pressure.
- Intrapleural pressure -
During the resting phase: 756mmHg.
During inspiration phase: 754mmHg
During the expiration phase: 756mmHg
- Intrapleural pressure -
How does air flow in and out of the lungs?
- Air flows into or out of the lungs because a pressure gradient exists between the atmosphere and the aveoli.
Air moves into the lungs when alveolar pressure is lower than atmospheric pressure. This occurs during the INSPIRATION PHASE of the breathing cycle.- Atmospheric pressure is 760mmHg
- Alveolar pressure is 758mmHg
pressure, air moves into the lungs.
When does air move out of the lungs?
Air moves out of the lungs when alveolar pressure is higher than atmospheric pressure. This occurs during the EXPIRATION PHASE of the breathing cycle
- Atmospheric pressure is 760mmHg
- Alveolar pressure is 762mmHg
What happens if there is no pressure gradient between atmospheric and alveolar pressures?
Then there is no movement of air. This occurs during the resting stage of the breathing cycle.
- This is when atmoshperic and alveolar pressure is both
760 mmHg.
What is a negative pressure?
Anytime a pressure is lower than atmospheric pressure and functions like a vacuum that has a suction like force. The suction of the vacuum couples the lungs to the chest wall via the pleura to form the lung-chest wall system. As a result, if the thoracic cavity increases in size, the lungs also expand. If it decreases, the lungs recoil or become smaller.
The changes in volume caused by alterations in thoracic cavity size in turn cause a change in alveolar pressure.
What are the two pressures that determine if your will inhale, exhale, or rest?
Atmospheric & Alveolar pressure.
Why does intrapleural pressure not affect your breathing?
In normal circumstances, air never gets into intrapleural space. So intrapleural pressure does NOT affect your breathing.
HOWEVER
Intrapleural pressure indirectly affects breathing because it is responsible for causing the lung-chest wall system which makes the lung volume change with changes of the size of the thoracic cavity. These changes in lung volume in turn cause the changes in alveolar pressure that will in turn allow you to inhale or exhale or rest.
How does this happen?
in Boyles Law, if you have a gas located in a container, then the gas in that container is inversely proportional to the size of the container. Ex: if the gas is air and the container is an alveolus, the alveolar pressure is inversely proportional to the size of the alveolus. So if the volume of the alveolus increases, the alveolar pressure decreases. and vice versa.
SUMMARY *** In order for you to breathe, the alveolar pressure must decrease from 760 mmHg to 758 mmHg. According to Boyle’s Law, to get the pressure to decrease is by increasing the volume of the alveolus
How do you increase the volume of the alveoli?
If the lungs expand, the aveoli becomes larger, making the alveolar pressure decrease to 758 mmHg and then inhalation occurs.
How did you make the thoracic cavity get bigger in order to make the lungs expand?
In order for inspiration to occur, certain chest muscles contract that in turn makes the thoracic cavity get bigger. When the thoracic cavity gets bigger, the lungs expand. When the lungs expand, the alveoli expand, alveolar pressure decreases and then inhalation occurs.
How do you exhale?
In order to exhale, alveolar pressure has to increase to 762mmHg, which is above the atmoshperic pressure of 760mmHg.
According to Boyle’s Law, the way that you get the alveolar pressure to increase is by decreasing the volume of the alveolus.
How do you decrease the volume of the alveoli?
If the chest wall recoils, the lungs get smaller. If the lungs get smaller, the alveoli gets smaller, making the alveolar pressure increase to 762mmHg, and then exhalation occurs.
How did you make the chest wall get smaller in order to make the lungs get smaller?
For expiration to occur, certain chest muscles relax which cause the thoracic cavity to get smaller. When the thoracic cavity gets smaller, the lungs get smaller. When the lungs get smaller, the alveoli gets smaller, alveolar pressure increases, and then expiration occurs.
What regulates the muscles in the chest to start this whole process?
The respiratory center in the brain.
It correlates the muscles of breathing
Details of the breathing cycle:
The breathing cycle has 3 phases: rest, inspiration, and expiration
- REST: during the resting phase, alveolar pressure is
equal to atmospheric pressure (both 760mmHg). since there’s no pressure gradient, no air moves in or out. - INSPIRATION: external intercostal muscles contract. The contraction of the diaphram causes this muscle to drop from it’s arched position and flatten out. The contraction of the external intrercostal muscles pull the ribcage upwards. This has the mass effect of increasing the volume of the thoracic cavity. Decreases from 760 to 758mmHg and air flows from the atmosphere to the alveoli of the lungs.
What are the accesory muscles of inspiration?
Sternocleidomastoid muscles, scalenes, and pectoralis minor muscles, diaphram, external intracostal muscles.
EUPNEA & TIDAL VOLUME
.
What is eupnea? aka normal quiet breathing
The main pattern of respiratory movement
When does eupnea occur?
What does a normal tidal volume mean?
- Eupnea occurs when a person exhibits a normal tidal
volume.- A normal tidal volume means that 500 mL of air are
inhaled and then are exhaled her breath (or breathing
cycle). - Tidal volume is so-named because it is similar to the
movements of a tidal wave. The 500 mL volume of air
that goes into the lungs during inspiration is like the
tidal wave when it moves toward the shore. And the
500 mL volume of air that leaves the lungs during
expiration is like the tidal wave when it moves away
from the shore, going back into the ocean.
- A normal tidal volume means that 500 mL of air are
RESPIRATORY RATE
.
What is the respiratory rate?
- The number of breathing cycles per unit of time,
usually expressed in breaths per minute.
What is the average respiratory rate in an adult?
12 breaths per minute (with each breath being the equivalent of one breathing cycle).
SPIROMETRY
.
What is spirometry?
When is spirometry preformed/used?
- Spirometry is the process by which lung volumes and
capacities are measured.
- Spirometry is performed in order to determine if lung function is normal.
What is the apparatus used to measure the volumes of air inspired and expired called?
- Spirometer.
What does the spirometer consist of/how does it work?
- The spirometer consists of a tube that the patient
breathes into. - The tube is connected to a reservoir filled with water
and a bell that floats within the water. - The floating bell moves down as the person inhales
and moves up as the person exhales. - As the floating bell moves up or down, an attached
pen recorder graphs the lung volumes and capacities
on a piece of paper located on a moving drum. - Once the procedure is completed, the drum and pen recorder are turned off, and the paper is removed and analyzed.
What is a spirogram?
The paper that graphically shows the lung volumes and capacities of the patient.
Lung volumes are shown on the left & lung capacities are shown on the right.
Difference between a lung volume & a lung capacity?
- A lung volume is a single volume
- A lung capacity is a combination of lung volumes
With the exception of tidal volume, lung volumes and lung capacities differ between men and women because men typically usually have larger bodies and larger lung volumes and capacities. The mL for men is shown first on the spirogram, and the women are shown in parentheses.
IMPORTANT: FOR THE EXAM YOU SHOULD KNOW
DEFINITIONS:
- Inspiratory Reserve Volume: The maximum volume of
air that can inspired AFTER a normal inspiration is the
IRV. (The extra volume of air that can be inspired with maximal effort after reaching the end of a normal, quiet
inspiration.
Men: 3100mL Women: 1900mL - Tidal Volume: Volume of air inspired or expired during
a single breathing cycle under resting conditions. (The
amount of air that moves in or out of the lungs with each
respiratory cycle).
500mL per breath in Men AND Women - Expiratory Reserve Volume: The maximum volume of air that can be expired after a normal expiration.
Men: 1200mL Women: 700mL - Residual Volume: the amount of air that remains in a
person’s lungs after maximum expiration.
Men: 1200mL Women: 1100mL - Functional Residual Capacity: the volume of air in the
lungs at the end of a normal expiration. So, after this
you still have the ERV / wind left. FRC is the sum of the
ERV + RV
Men: 2400mL Women: 1800mL
Why does the IRV and ERV have different mL numbers of air volume in the last flashcard?
- Because it is easier for air to enter the lungs than it is
to leave the lungs because the respiratory tract has a
lot of branches and these branches temporarily trap
some of the air. Kind of like when people easily enter a
cornmaze and then they get kind of lost.
ERV: the people in the cornmaze take a while to find their way out
RV: the people get STUCK in the cornmaze. RV is a constant volume but the air inside of it periodically changes.
Residual Volume Details:
- There are certain equations you can use to calculate
the residual volume- Although residual volume does not normally come out
of the body, The residual volume can leave the body if
you get the wind knocked out of you / a blow to the
chest. - Residual Volume helps to keep the alveoli open
- Although residual volume does not normally come out
Lung Capacities Details:
- Lung capacities are combinations of lung volumes
- Functional Residual Capacity: the volume of air in the
lungs at the end of a normal expiration. So, after this
you still have the ERV / wind left. FRC is the sum of the
ERV + RV
Men: 2400mL Women: 1800mL - The Inspiratory Capacity: the maximum volume of air
that can be inspired after a normal expiration.
IC is the Sum of the TV + IRV
Men: 3600mL Women: 2400mL
- Functional Residual Capacity: the volume of air in the
- if you are administering spirometry, you’d tell your patient to breathe out normally and then maximally breath in as much as possible.
- Vital Capacity: the maximum volume of air that can be expired after a maximum inspiration. So if you maximally inspire, your lungs bring in a TD + IRV. These will add to your ERV and residual volume already in the lungs. Then you can blow out the IRV, TD, and ERV. VC is theSum of the IRV, TD, and ERV
Men: 4800mL Women: 3100mL
- Vital Capacity: the maximum volume of air that can be expired after a maximum inspiration. So if you maximally inspire, your lungs bring in a TD + IRV. These will add to your ERV and residual volume already in the lungs. Then you can blow out the IRV, TD, and ERV. VC is theSum of the IRV, TD, and ERV
- If you are preforming spirometer you’d tell the patient to maximally inhale and then maximally exhale.
- The Total Lung Capacity: the total volume of air in the lungs after a maximum inspiration. This is the sum of all four lung volumes. TLC is the sum of the VC and RV
Men: 6000mL Women: 4200mL
TLC can not be determined with spirometry.
- The Total Lung Capacity: the total volume of air in the lungs after a maximum inspiration. This is the sum of all four lung volumes. TLC is the sum of the VC and RV
RESIDUAL MINUTE VOLUME:
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What is the residual minute volume?
What does this equal to?
- The respiratory minute volume, also known as the minute ventilation, is the amount of air that flows into and out of the entire respiratory system per minute.
- The respiratory minute volume (or V dot) equals the product of the tidal volume (or V sub T) and the respiratory rate (or RR). Under normal resting conditions, tidal volume equals 500 mL per breath, and the respiratory rate equals 12 breaths per minute. Therefore, the normal respiratory minute volume equals 6000 mL per minute, which is the equivalent of 6 L/min. This means that each minute, 6 liters of air go into and out of the entire respiratory system.
ALVEOLAR MINUTE VOLUME
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How do you get thealveolar minute volume?
As you just learned in the previous video, the respiratory minute volume (or minute ventilation) tells you how much air goes into and out the entire respiratory system per minute. HOWEVER, the respiratory minute volume does NOT tell you how much of that air actually undergoes gas exchange.
- If you want to know how much air undergoes gas exchange, you have to calculate the alveolar minute volume. The alveolar minute volume, also known as the alveolar ventilation, is the volume of air that reaches the respiratory zone per minute. In other words, it is the volume of air that undergoes gas exchange per minute. To calculate the alveolar minute volume (or V dot sub A), take the tidal volume (or V sub T) and subtract from the anatomical dead space (or V sub D) and then multiply the result by the respiratory rate (or RR). The anatomical dead space is the volume of air that does not undergo gas exchange. The anatomical dead space is equal to the conducting zone, the part of the respiratory system from the nose to the terminal bronchioles. The volume of the conducting zone is about 150 mL/breath. So, the anatomical dead space is 150 mL/breath. By subtracting the anatomical dead space from the tidal volume, you are left with the volume of air that enters the respiratory zone. That volume is about 350 mL of air per breath under resting conditions. If you take the 350 mL volume per breath and multiply that times the respiratory rate of 12 breaths per minute, then you end up with an alveolar minute volume of 4200 mL/min, which is the equivalent of 4.2 L/min. This means that each minute, 4.2 L of air undergo gas exchange in the respiratory system.