Chapter 23_AP2 Flashcards
Respiratory System
What are the 5 functions of the respiratory system?
- Regulation of blood pH
- Production of chemical mediators
- Voice production
- Olfaction
- Protection
Ventilation:
Movement of air into and out of lungs
External respiration:
Gas exchange between air in lungs and blood
•Transport of oxygen and carbon dioxide in the blood
Internal respiration:
Gas exchange between the blood and tissues
Upper tract:
nose, pharynx and associated structures
Lower tract:
larynx, trachea, bronchi, lungs and the tubing within the lungs
The nose consists of:
external nose and nasal cavity
Nasal Cavity consists of:
divided by the nasal septum;
anterior vestibule contains hairs that trap debris;
lined with pseudostratified ciliated columnar epithelium that traps debris and moves it to the pharynx
Openings of the nasal cavity:
nares open to the outside, and the choanae lead to the pharynx;
paranasal sinuses and the nasolacrimal duct open into the nasal cavity
Hard palate:
floor of nasal cavity
Nasal septum:
partition dividing cavity; cartilage and bone
Conchae:
bony ridges on lateral walls with meatuses between. Openings to paranasal sinuses and to nasolacrimal duct
What are the functions of the nasal cavity?
- Passageway for air
- Cleans the air
- Humidifies, warms air
- Smell
- Along with paranasal sinuses are resonating chambers for speech
Paranasal sinuses:
frontal, ethmoid, sphenoid, and maxillary
Where does the nasopharynx begin and where does it end?
joins the nasal cavity through the internal choanae
What structures are found within the nasopharynx?
contains the openings to the auditory tube and the pharyngeal tonsils
What type of tissue lines the nasopharynx?
pseudostratified columnar epithelium with goblet cells.
Where does the oropharynx begin and where does it end?
shared with digestive system
What structures are found within the oropharynx?
contains the palatine and lingual tonsils
What type of tissue lines the oropharynx?
Lined with moist stratified squamous epithelium.
Where does the laryngopharynx begin and where does it end?
epiglottis to esophagus
What type of tissue lines the laryngopharynx?
Lined with moist stratified squamous epithelium
Larynx
The cartilage within is connected by muscles and ligament; anchored by its connection to the hyoid bone and the
trachea.
What is the opening within the larynx known as?
Vocal folds (vocal cords)
Thyroid cartilage:
largest, Adam’s apple
Cricoid cartilage:
most inferior, base of larynx
Epiglottis:
attached to thyroid and has a flap near base of tongue. Elastic rather than hyaline cartilage
Arytenoids:
attached to cricoid
Corniculate:
attached to arytenoids
Cuneiform:
contained in mucous membrane
Unpaired cartilage in the larynx:
Thyroid
Cricoid
Epiglottis
Paired cartilage in the larynx:
Arytenoid (2)
Corniculates (2)
Cuneiform (2)
What are the superior ligaments?
extend from the anterior surface of the arytenoid cartilages to the posterior surface of the thyroid cartilage;
How are the vestibular folds (false vocal cords) related to the
superior ligaments?
the superior ligaments are covered by a mucous membrane called the vestibular folds, or false vocal cords
How are the vocal fold (true vocal cords) related to the inferior
ligaments?
The inferior ligaments are covered by a mucous membrane called the vocal folds, or true vocal cords.The vocal folds and the opening between them are called the glottis. The vestibular folds and the vocal folds are lined with stratified squamous epithelium.
Functions of the larynx:
- Maintain an open passageway for air movement:
- Epiglottis and vestibular folds prevent swallowed material from moving into larynx
- Vocal folds are primary source of sound production.
- The pseudostratified ciliated columnar epithelium traps debris, preventing their entry into the lower respiratory tract.
True vocal cords or vocal folds:
sound production. Opening between is glottis
How are sound waves produced?
produced as the vocal folds vibrate when air passes through the larynx. Tightening the folds produces sounds of different pitches by controlling the length of the fold, which is allowed to vibrate.
How is the amplitude of sound (volume) controlled?
Greater the amplitude of vibration, louder the sound.
What is the relationship between frequency and pitch?
higher-frequency vibrations producing higher-pitched sounds and lower-frequency fibrations producing lower-pitched sounds
What changes in the in the vocal folds change the frequency of the
sound produced?
Variations in the length of the vibrating segments of the vocal folds affect the frequency of the vibrations. Higher-pitched tones are produced when only the anterior parts of the folds vibrate, and progressively lower tones result when longer sections of the folds vibrate
How are the length and tension of the vocal folds controlled?
Movement of the arytenoid and other cartilages is controlled by skeletal muscles, thereby changing the position and length of the vocal folds.
Why do males have lower pitched voices?
Because males usually have longer vocal folds than females.
Describe the anatomy and histology of the trachea.
connects the larynx to the main bronchi; Membranous tube of dense regular connective tissue and smooth muscle; supported by 15-20 hyaline cartilage C-shaped rings open posteriorly; divides to form left and right bronchi
Carina:
cartilage at bifurcation. Membrane especially sensitive to irritation and inhaled objects initiate the cough reflex
Explain how the Heimlich maneuver can be used to treat tracheal blockage:
are designed to force an object out of the air passage by the sudden application of pressure to the abdomen.
Explain how Intubation can be used to treat tracheal blockage:
a tube is passed through the mouth or nose into the pharynx and then through the larynx to the trachea.
Explain how a Tracheostomy can be used to treat tracheal blockage:
an operation performed to make an opening into the trachea, commonly between the second and third cartilage rings. Usually, the opening is intended to be permanent, and a tube is inserted into the trachea to allow airflow and provide a way to remove secretions.
Explain how a Cricothyrotomy can be used to treat tracheal blockage:
The preferred point of entry in emergency cases is through the membrane between the cricoid and thyroid cartilages
Right and left primary bronchi
Main bronchi
Secondary bronchi
Lobar bronchi
Tertiary bronchi
Segmental bronchi
Ventilation refers to the
movement of air into and out of the lungs.
Internal respiration refers to
gas exchange between the blood and body tissues
Whenever people cry, their nose runs. This is because the _____ drain tears into the nose.
nasolacrimal ducts
A molecule of air enters the nose through the external nares. What is the correct pathway to the trachea?
nasal cavity, pharynx, larynx, trachea
What is the passageway for both air and food?
pharynx
The largest of the laryngeal cartilages is the
thyroid cartilage
The ring of cartilage that forms the base of the larynx is the
cricoid cartilage.
During swallowing, the opening into the larynx is covered by the
epiglottis
When air passes through the glottis, which structures vibrate to produce sound?
vocal folds (cords)
The pitch of the sound produced by the vocal cords is controlled by the
frequency of the vibrations
Each lobe of each lung is supplied by a
secondary bronchus
The diameter of bronchioles can change because their walls contain
smooth muscle
Gas exchange between the air in the lungs and the blood takes place in the
alveoli
Constriction of smooth muscle in the bronchioles does what?
restricts the flow of air into the lungs
Which of the following muscles increases the volume of the thorax during a normal inhalation?
1) diaphragm
2) external intercostals
3) internal intercostals
4) rectus abdominis
1) diaphragm
2) external intercostals
Expiration during quiet breathing occurs when:
the diaphragm and external intercostal muscles relax
Oxygenated blood is carried to the walls of the bronchi and tissues of the lungs via the
bronchial arteries
When the inspiratory muscles contract:
thoracic volume increases
For air to flow into or out of the lungs, there must be:
a pressure gradient established between the atmosphere and the alveoli.
During expiration, the alveolar pressure must be:
greater than atmospheric pressure.
Surfactant facilitates alveolar ventilation by
decreasing the surface tension between water molecules on the lining of the alveoli
Air in the pleural cavity is called
a pneumothorax
Mr. Huff and Puff exhales normally; then, using forced expiration, he exhales as much air as possible. The volume of air still remaining in his lungs is called
residual volume
Oxygen and carbon dioxide are exchanged across the respiratory membrane by the process of
diffusion
Oxygen diffusion from the alveolus to the pulmonary capillary occurs because
alveolar PO2 is greater than capillary PO2
The Bohr effect refers to the
effect of pH on the oxygen-hemoglobin dissociation curve
How does an increase in the acidity of the blood affect the ability of hemoglobin to bind oxygen?
As blood acidity increases, hemoglobin binds less oxygen
What is normal blood pH?
7.4
Most carbon dioxide is transported in the blood in the form of:
bicarbonate ions
The chloride shift refers to
the exchange of chloride ions for bicarbonate ions across the red blood cell membrane
If there is an accumulation of acidic products in the plasma, one would expect
an increase in respiration rate
The ventral respiratory group stimulates
the intercostal and abdominal muscles
After hyperventilating for several minutes, a person may develop short periods of apnea because
the level of CO2 decreases below the level necessary to stimulate the inspiratory center
The Hering-Breuer reflex
helps prevent overinflation of the lungs.
When one is exercising, their respiratory rate increases due to:
increased blood carbon dioxide levels stimulating the chemoreceptors
Expiratory Reserve Volume
The amount of air that can be forcefully expired after expiration of the normal tidal volume
Vital Capacity
Sum of the expiratory reserve, inspiratory reserve, and tidal volumes
Residual Volume
Volume of air remaining in lungs after the most forceful expiration
Total lung capacity
Sum of the inspiratory reserve, expiratory reserve, tidal, and residual volumes
layers of the respiratory membrane :
- A thin layer of fluid lining the alveolus
- The alveolar epithelium composed of simple squamous epithelium
- The basement membrane of the alveolar epithelium
- A thin interstitial space
- The basement membrane of the capillary endothelium
- The capillary endothelium, composed of simple squamous epithelium
What is the significance of the respiratory membrane?
It is the
area where oxygen and carbon dioxide are exchanged.
Tracheobronchial Tree
divides to form two main bronchi, which extend to the lungs. The main bronchi divide to form lobar bronchi, which divide to form segmental bronchi, which divide to form bronchioles, which divide to form terminal bronchioles.
- The trachea to the terminal bronchioles is a passageway for
air movement
Gas exchange occurs between:
the respiratory bronchioles and the alveoli
- The components of the respiratory membrane are:
a film of water, the walls of the alveolus and the capillary, and an interstitial space
Terminal bronchioles divide to form:
respiratory bronchioles, which give rise to alveolar ducts
Lungs
are divided into lobes, bronchopulmonary segments, and lobules
Respiratory zone:
site for gas exchange
Three types of cells in respiratory membrane:
- Type I pneumocytes
- Type II pneumocytes
- Dust cells
Type I pneumocytes
Thin squamous epithelial cells, form 90% of surface of alveolus. Gas exchange.
Type II pneumocytes
Round to cube-shaped secretory cells. Produce surfactant
Dust cells
(phagocytes)
Anatomy of the lungs:
2; Base sits on diaphragm, apex at the top, hilus on medial surface where bronchi and blood vessels enter. All the structures in hilus called root
Right Lung:
three lobes. Lobes separated by fissures
Left Lung:
Two lobes, and an indentation called the cardiac notch
Lobes are supplied by:
secondary bronchi
lobules are supplied by:
bronchioles and separated by incomplete partitions
List the structures which form the thoracic wall.
•Thoracic vertebrae, ribs, costal cartilages, sternum and associated muscles; Thoracic cavity; Diaphragm
Thoracic cavity
space enclosed by thoracic wall and diaphragm
Diaphragm
separates thoracic cavity from abdominal cavity
Inspiration:
diaphragm, external intercostals, pectoralis minor, scalenes
Expiration:
muscles that depress the ribs and sternum: abdominal muscles and internal intercostals
Labored breathing:
all inspiratory muscles are active and contract more forcefully. Expiration is rapid
Pleural cavity
surrounds each lung and is formed by the pleural membranes. Filled with pleural fluid.
Visceral pleura:
adherent to lung. Simple squamous epithelium, serous.
Parietal pleura:
adherent to internal thoracic wall.
Pleural fluid:
acts as a lubricant and helps hold the two membranes close together (adhesion).
Mediastinum:
central region, contains contents of thoracic cavity except for lungs.
Two sources of blood to lungs:
Pulmonary artery & bronchial arteries
Where do the pulmonary arteries come from and what type of blood do they
carry?
brings deoxygenated blood to lungs from right side of heart to be oxygenated in capillary beds that surround the alveoli. Blood leaves via the pulmonary veins and returns to the left side of the heart.
Where do the pulmonary veins go and what type of blood do they carry?
Blood going to left side of heart via pulmonary veins carries primarily oxygenated blood, but also some deoxygenated blood from the supply of the walls of the conducting and respiratory zone.
Ventilation
Movement of air into and out of lungs;
Air moves from area of higher pressure to area of lower pressure
Boyle’s Law:
P = k/V, where P = gas pressure, V = volume, k = constant at a given temperature
Lung recoil causes alveoli to collapse resulting from
Elastic recoil
Surface tension
Elastic recoil:
elastic fibers in the alveolar walls
Surface tension:
film of fluid lines the alveoli. Where water interfaces with air, polar water molecules have great attraction for each other with a net pull in toward other water molecules. Tends to make alveoli collapse.
Surfactant:
Reduces tendency of lungs to collapse by reducing surface tension. Produced by type II pneumocytes
Respiratory distress syndrome (hyaline membrane disease).
Common in infants with gestation age of less than 7 months. Not enough surfactant produced.
Pneumothorax
an opening between pleural cavity and air that causes a loss of pleural pressure
Spirometry:
measures volumes of air that move into and out of respiratory system.
Tidal volume:
amount of air inspired or expired with each breath. At rest: 500 mL
Inspiratory reserve volume:
amount that can be inspired forcefully after inspiration of the tidal volume (3000 mL at rest)
Expiratory reserve volume:
amount that can be forcefully expired after expiration of the tidal volume (100 mL at rest)
Residual volume:
volume still remaining in respiratory passages and lungs after most forceful expiration (1200 mL)
Minute ventilation:
total air moved into and out of respiratory system each minute; tidal volume X respiratory rate
Respiratory rate (respiratory frequency):
number of breaths taken per minute
Diffusion of gases through the respiratory membrane depends upon four factors
- Membrane thickness. The thicker, the lower the diffusion rate
- Diffusion coefficient of gas (measure of how easily a gas diffuses through a liquid or tissue). CO2 is 20 times more diffusible than O2, surface areas of membrane, partial pressure of gases in alveoli and blood
- Surface area. Diseases like emphysema and lung cancer reduce available surface area
- Partial pressure differences. Gas moves from area of higher partial pressure to area of lower partial pressure. Normally, partial pressure of oxygen is higher in alveoli than in blood. Opposite is usually true for carbon dioxide
Shunted blood:
blood that is not completely oxygenated
Apnea.
Cessation of breathing.
Hyperventilation.
Causes decrease in blood PCO2 level.
Hypoxia:
decrease in oxygen levels below normal values
Hering-Breuer Reflex
Limits the degree of inspiration and prevents overinflation of the lungs
