Chapter 21- Respiratory System Flashcards
What is included in the anatomy of the respiratory system?
blood vessels of the pulmonary circuit
rib cage and respiratory muscles
both lungs and the respiratory tract
What are the hollow passages that the respiratory tract consists of?
Nose Pharynx Larynx Trachea Bronchial Tree (bronchi, bronchioles)
What is included in the upper respiratory tract?
passageways from the nasal cavity to the larynx
What is included in the lower respiratory tract?
Passageways from the trachea to the respiratory tracts terminal structures– the alveoli
What are alveoli?
Tiny air sacs arranged in grape-like clusters where gases are exchanged
Describe the conducting zone
Conduits through which air travels on its way in and out of the body as it is inhaled and exhaled
Nose and nasal cavity through the bronchioles
Describe the respiratory zone
Where gases are exchanged
structures that contain alveoli
What is respiration?
Process that provides the body’s cells with oxygen and removes CO2
4 separate processes
What are the 4 processes of respiration?
Pulmonary ventilation
Pulmonary gas exchange
Gas transport in the blood
Tissue gas exchange
Functions besides respiration that the respiratory system is involved with to maintain homeostasis
Speech
Detecting odors
Helping to expel contents of the abdominopelvic cavity
Assisting in flow of venous blood and lymph in the abdomen
Maintaining acid base homeostasis
Assisting in production of angiotensin II for maintenance of blood pressure and fluid homeostasis
Summarize the functions of the nose and nasal cavity as the entryway to the respiratory system
Warm and humidify inhaled air
Filter out debris from inhaled air
House olfactory receptors
Enhance the resonance of the voice
What is the area just inside the nostril that contains bristle-like hairs?
The vestibule
What are the bones that fill out the space in the nasal cavity? What are the passages they curl around?
Superior and middle and inferior conchae
Curl around the: Superior, middle and inferior nasal meatuses
What do we call the hollow cavities found within the frontal, ethmoid, sphenoid and maxillary bones?
Paranasal sinuses
What type of tissue is the vestibule lined with?
Stratified squamous epithelium– which resists mechanical stress
Beyond the vestibule the epithelium changes from stratified squamous to:
Olfactory mucosa
and
Respiratory mucosa
What type of cells is the rest of the nasal cavity lined with?
Pseudostratified columnar epithelium and goblet cells
What are goblet cells?
glands that secrete mucous
Common name for the pharynx
Throat
Common name for the larynx
voice box
What are the three anatomical divisions of the pharynx?
Nasopharynx
Oropharynx
Laryngopharynx
What is the function of the larynx?
Keeps food and liquid out of the respiratory tract
Houses vocal cords involved in sound production
Common name for the trachea
windpipe
What is the shape of the cartilage rings of the trachea, what are they made of?
C-shaped and make of hyaline cartilage
What is the name of the last tracheal cartilage ring before the trachea splits to the bronchi?
Carina
Where do the bronchi enter the lungs?
At the hilum
What do the primary bronchi branch into?
Secondary bronchi
What do the secondary bronchi branch into?
10 smaller tertiary bronchi
After the primary bronchi, what happens to the cartilage rings?
Changes from c-shaped to complete rings
Amount of smooth muscle also increases
What are bronchioles and what are they made of?
Smallest airways in the bronchial tree
Made of simple cuboidal epithelium
How many alveolar ducts do each respiratory bronchiole branch into?
Two or more
3 types of cells in alveolus
Type I alveolar cells
Type II alveolar cells
Alveolar macrophages (dust cells)
Structure and function of Type I alveolar cells
Squamous cells- make up 90% of alveolar wall
Very thin, permitting rapid exchange of gases across plasma membrane
Structure and function of Type II alveolar cells
Small cuboidal cells- 10% of alveolar wall
Contain surfactant which helps reduce surface tension on the alveoli
Structure and function of alveolar macrophages
Phagocytes from bone marrow.
Move around alveoli cleaning up debris not filtered in bronchial tree
How many lobes does the right lung have?
three
How many lobes does the left lung have?
Two
What are the lobes of the lungs further divided into?
Broncopulmonary segments
What are bronchopulmonary segments further divided into?
hexagonal structures called lobules
What vessels are responsible for supplying the tissues of the lung with blood and nutrients?
Bronchial arteries
What is the name of the membrane that surrounds the lungs and attaches to the rib cage and diaphragm?
Parietal pleura
What does the parietal pleura become when it folds over on itself at the hilum?
Visceral pleura
What is the function of pleural fluid and where does it come from?
Secreted by the pleural membranes
Lubricates the lungs as they expand and contract, reducing friction
Pulmonary ventilation is the first process of respiration. What are the two phases it consists of?
Inspiration (inhalation)
Expiration (exhalation)
What is required to move gas molecules in the body during pulmonary ventilation when additional energy is not used?
Gradients
Describe Boyle’s law
When temp and # of molecules are constant, pressure and volume of gas are inversely related
As volume of container increases, pressure gas exerts on its container decreases
How are pressure gradients created?
volume changes in the thoracic cavity
Since lungs cannot change volume on their own, what do they rely on to do it for them? What are two types?
Inspiratory muscles
Diaphragm and external intercostal muscles
What are the three pressures at work during ventilation?
Atmospheric
Intrapulmonary
Intrapleural
What are the three primary physical factors of the respiratory tracts and lungs that influence overall effectiveness of pulmonary ventilation?
Airway resistance
Alveolar surface tension
Pulmonary compliance
Instrument that produces a graph that records normal inhalation and exhalation
Spirometer
What is tidal volume?
The amount of air inspired or expired during normal quiet ventilation– 500 ml in a normal adult
What is inspiratory reserve volume?
The volume of air that can be forcibly inspired after a normal tidal volume inspiration
IRV averages 2100-3300 ml of air
What is expiratory reserve volume?
Opposite of IRV, the amount of air that can be forcibly expired after normal tidal volume expiration
ERV averages 700-1200ml air
What is residual volume?
air remaining in the lungs after even the most forceful expiration
What is the inspiratory capacity?
total volume of air that a person can inspire after a tidal volume
TV+IRV=inspiratory capacity
What is the functional residual capacity?
Amount of air normally left in the lungs after tidal expiration
ERV+RV=functional residual volume
What is the vital capacity?
total amount of exchangeable air or the amount of air that can move in and out of the lungs
TV+IRV+ERV=vital capacity
What is the total lung capacity?
Sum of all 4 pulmonary volumes– represents the total amount of exchangeable and nonexchangeable air in the lungs
IRV+TV+ERV+RV=TLC
What happens during pulmonary gas exchange?
Exchange of gases between the alveoli and blood
What happens during tissue gas exchange?
Exchange of gases between the blood in systemic capillaries and the body’s cells
Describe Dalton’s Law of partial pressures
Each gas in a mixture exerts its own pressure (partial pressure). So the total pressure of a gas mixture is a sum of the partial pressures of its gases
Discuss Henry’s law
Degree to which a gas dissolves in a liquid is proportionate to both its partial pressure and its solubility in the liquid
What is the PO2 of blood in the capillaries and alveoli air?
40mmHg and 104 mmHg
Favors diffusion of O2 INTO the blood
What is the PCO2 in the capillaries and alveoli air?
45 mmHg and 40 mmHg
Not as high as PO2 but is aided by CO2’s high solubility in water
What is the surface area of the respiratory membrane? Quantity of blood in pulmonary capillaries?
1000 square feet
75-100 ml
What is hypoxemia?
Low level of oxygen in the blood
What is hypercapnia?
High level of CO2 in the blood
What is the “thickness” of the respiratory membrane?
The distance a gas must diffuse
What is ventilation-perfusion matching?
Coupling
Degree of match between the amount of air reaching the alveoli (ventilation) and the amount of blood flow (perfusion), in the pulmonary capillaries
What is tissue gas exchange?
The exchange of oxygen and CO2 between the blood and tissues.
Factors that affect efficiency of tissue gas exchange
Surface area availability
Distance for diffusion
Perfusion of the tissue
How is oxygen transported through the blood?
Hemoglobin
What is hemoglobin?
Protein found in erythrocytes consisting of 4 subunits, each containing a heme group.
Each heme group contains one iron atom that can bind to one molecule of oxygen– so each hemoglobin can carry 4 oxygen molecules
How does hemoglobin bind and release oxygen?
Loading and unloading
What happens during loading?
Oxygen fromalveolibinds to hemoglobin in the pulmonary capillaries which converts deoxyhemoglobin to oxyhemoglobin
What does it mean when Hb is partially saturated?
It only has 1-3 molecules O2 bound to it
What does it mean when Hb is fully saturated?
It has 4 molecules O2 bound to it
What happens during unloading?
Hb in the systemic capillaries releases O2 to the cells of the tissues
What two factors does Hb’s ability to load or unload O2 depend on?
Percent O2 saturation of Hb
Blood PO2
What are the three ways CO2 is transported from the tissues back to the lungs?
Dissolved in plasma
Bound to Hb as carbaminohemoglobin
As bicarbonate ions
What is the carbonic acid-bicarbonate buffer system?
Homeostatic mechanism involving the balance of carbonic acid, bicarbonate ion and CO2 to maintain pH in the blood
What is hyperventilation?
Situation where the rate and/or depth of breathing increases.
Increases the amount of CO2 expired from the lungs which decreases PCO2 in the blood
Less carbonic acid is formed, less H+ formed and pH of blood increases and becomes more basic.
More oxygen may be dissolved in the blood
What is hypoventilation?
Rate and/or depth of breathing decreases.
Causes retention of CO2 and an increase in PCO2.
Carbonic acid is formed leading to more H+ formation and blood becomes more acidic.
Oxygen levels drop leading to hypoxemia.
What is respiratory alkalosis?
Can occur if hypoventilation continues, where hypocapnia (relative lack of CO2) results in blood pH increase
What is respiratory acidosis?
Can occur if hypoventilation continues, where hypercapnia, as increase in CO2 level, causes blood pH to decrease
What is Dyspnea?
Feeling of shortness of breath
What is eupnea?
Normal breathing
What is the part of the brainstem that controls ventilation?
Medulla oblongata and pons
What is the respiratory rhythm generator (RRG)?
Group of neurons that creates the basic rhythm for breathing, found within the superior, anterior medulla
What is the ventral respiratory group (VRG)?
Contains both inspiratory and expiratory neurons. Sends impulses to the spinal cord and eventually trigger action potentials in the phrenic nerve
What is the phrenic nerve?
Innervates the diaphragm and intercostals nerves that innervate the external intercostal muscles
What is the dorsal respiratory group (DRG)?
Primarily involved in integrating sensory info
Sends impulses along the same pathways as the VRG
What are chemoreceptors?
Specialized cells that respond to changes in the concentration of a specific chemical
Function of central chemoreceptors
initiate a feedback loop cycle by detecting changes in both CO2 and H+ concentrations by monitoring H+ levels in the cerebrospinal fluid
What are peripheral chemoreceptors and where are they found?
Specialized group of cells that detect PCO2 and H+ concentration. When arterial PCO2 falls below 70mmHg (100 is normal), these receptors send signals to the DRG along the glossopharyngeal and vagus nerves
Found in the carotid arteries and aorta
What is the response of the DRG when PCO2 falls below 70mmHg?
Rate and depth of ventilation increases
What do restrictive lung diseases do?
Decrease pulmonary compliance and reduce the effectiveness of inspiration by increasing alveolar surface tension and destroying elastic tissue in lungs
What effect do restrictive lung diseases have on inspiratory capacity, vital capacity and total lung capacity?
It decreases them and makes effective pulmonary ventilation difficult
Common restrictive lung diseases?
idiopathic pulmonary fibrosis
pneumoconiosis
neuromuscular diseases
chest wall deformities
What do obstructive lung diseases do?
Increase airway resistance which decreases the efficiency of expiration.
This resistance can lead to the collapse of airways after expiration due to otherwise normal recoil of elastic tissue
traps O2 poor, CO2 rich air in the alveoli
Residual volume increases and vital capacity decreases
Common obstructive lung diseases?
Emphysema
Asthma
Lung cancer
