Week 9: Respiratory Function Flashcards
What is the function of the Respiratory system?
- Provide oxygen to body tissues for cellular respiration.
- Removes waste product carbon dioxide (CO2).
- Maintains acid-base balance.
- Sense odors.
- Speech production.
What are the two zones of the Respiratory system?
Conducting and Respiratory zones
What does the Conducting zone do?
- Provides route for incoming/outgoing air
- Removes debris and pathogens
- Warms/humidifies incoming air
- Aids in detecting odours, metabolizing airborne
carcinogens
What does the Respiratory zone do?
It is where gas exchange occurs
What parts make up the Conducting zone?
Nose, nasal cavity, pharynx, larynx, trachea, bronchi/brochioles.
What parts make up the Respiratory zone?
Respiratory brochioles, alveolar ducts, alveoli.
What is the External nose?
Surface/skeletal structures that result in appearance and function
Name the different parts of the Nose
Root
Bridge
Dorsum nasi
Apex
Philtrum
Where is the Root of the nose located?
Located between the eyebrows
What is the Bridge of the nose?
Connects the root to the rest of the nose
What is the Dorsum nasi of the nose?
The length of the nose
What is the Apex of the nose?
Tip of the nose
What are the nostrils of the nose made up of?
Alae (ala=singular) which are cartilaginous structure forming lateral side of each nare (nostril opening).
What is the Philtrum of the nose?
A concave surface connecting apex of nose to upper lip
Which parts of the nose consist of bone?
Root and bridge
The protruding portion of the nose consists of what?
Cartilage
What is the Nasal bone?
A pair of bones lies under root/bridge, articulates superiorly with frontal bone and laterally with maxillary bones
What is Septal cartilage?
It is flexible, connected to nasal bone forming forum nasi
What is Alar cartilage?
It consists of the apex of the nose/surrounds the naris (nares)
What are the nares?
They open into nasal cavity-separated into L/R sections by nasal septum
What is the Nasal Septum?
Wall composed of bone and cartilage that separates the left and right nasal cavities
What is the nasal cavity?
Lateral wall has 3 bony projections called conchae
What do Conchae do?
Increase surface area of nasal cavity-helps direct air flow in nose along epithelium where it is cleaned and warmed, also traps water during exhalation
What are Meatuses?
Attached to conchae (there are also 3) provide similar function to the conchae
What is the Hard Palate?
Anterior region of nasal cavity composed of bone
What is the Soft Palate?
Posterior portion of nasal cavity consists of muscle tissue
What are Paransal Sinuses?
Warm up and humidify incoming air, also produce mucus and lighten weight of skull
Sinuses are lined with what?
Mucosa
How are Sinuses named?
According to associated bones
What are the 4 Sinuses?
Frontal
Maxillary
Sphenoidal
Ethmoid
Nares and anterior nasal cavities are lined with what?
Mucous membranes, as well as sebaceous glands, hair follicles, and olfactory epithelium
What are hair follicles responsible for?
Preventing passage of large debris
What is the Olfactory epithelium responsible for?
Involved in detecting odours
Conchae, meatuses, paranasal sinuses lined by respiratory epithelium composed of…
pseudostratified (single layer) ciliated columnar epithelium
The respiratory epithelium contains Goblet cells to do what?
To produce mucous and trap debris
The respiratory epithelium contains Cilia to do what?
Help remove mucus & debris that help sweep materials towards throat to be swallowed
**Cold air slows movement of cilia (contributes to runny nose in winter)
How do the capillaries beneath the epithelium warm the air?
Convection
Serous and mucus producing cells secrete what?
Lysozyme and proteins (defensins) that have antibacterial properties
What is the Pharynx?
Tube formed by skeletal muscle, lined with mucous membrane that is continuous with nasal cavities
What are the 3 regions that the Pharynx is divided into?
Nasopharynx
Oropharynx
Laryngopharynx
What is the Nasopharynx?
Serves only as an airway, top of nasopharynx is the pharyngeal tonsils.
What is the Uvula?
Small bulbous structure at apex of soft palate, moves like a pendulum during swallowing, swing upward to close off nasopharynx to prevent ingested materials from entering nasal cavity
What are the Eustachian (auditory) tubes?
Tubes that connect each middle ear opening into nasopharynx
*Why colds often lead to ear infections
What is the Oropharynx?
Passageway for both air and food, contains 2 sets of tonsils: palatine and lingual
What is the Fauces?
The opening at the connection between the oral cavity and oropharynx
What are the Palatine tonsils?
Lateral to the oropharynx in the areas of fauces
What are the Lingual tonsils?
Located at the base of the tongue
What is the Laryngopharynx?
Continues route for ingested material and air until its inferior end where digestive and respiratory systems diverge; opens to the larynx and esophagus
What is the Larynx?
Connects pharynx to trachea; Helps regulate volume of air that enters/leaves lungs, also known as the voice box (houses vocal cords)
What are the 3 large cartilage pieces that make up the larynx?
Thyroid cartilage
Epiglottis
Cricoid cartilage
What is the Thyroid cartilage?
Anterior, largest piece, Consists of laryngeal prominence (“Adam’s apple)-more prominent in males
What is the Epiglottis?
Superior, three small-paired cartilages (arytenoids, corniculates, cuneiforms) attach to epiglottis and vocal cords to produce speech
What is the Cricoid cartilage?
Inferior, thick, forms a ring with wide posterior and thin anterior region
What does the Epiglottis do?
Flexible piece of elastic cartilage (attached to thyroid cartilage);
Covers opening of trachea;
When closed, unattached end of epiglottis rests on the glottis
What is the Glottis?
Composed of the false vocal cords and the true vocal cord, inner edges are free, allowing for oscillation to produce sound.
What are the False Vocal cords?
One of a pair of folded sections of mucous membrane
What is the True Vocal cord?
One of the white, membranous folds attached by muscle to the thyroid and arytenoid cartilages of larynx on outer edges
What does swallowing do to the pharynx and larynx?
It causes them to swing downwards and close the opening to the trachea, producing a larger area for food to pass through.
What is the Trachea?
Extends from the larynx towards the lungs, made up of 16-20 c-shaped pieces of hyaline cartilage.
What is the Fibroeleastic membrane do?
Composed of trachealis muscle and elastic connective tissue, that closes posterior surface of trachea.
It connects C-shaped cartilages-provide structural support preventing tracheal collapse, and allows trachea to stretch/expand
Where does the Trachea branches split?
Trachea branches into the R/L primary bronchi at the carina
What is the Carina?
Raised structure containing specialized nervous tissue, induces violent coughing if a foreign body (food) is present
What are the Bronchi?
Provides passageway for air in/out of lungs; Primary bronchi enters lungs at the hilum (concave region where blood vessels, lymphatic vessels and nerves enter the lungs)
What are the further/smaller branches of the Bronchi?
Secondary bronchi, Tertiary bronchi, Bronchioles
What is the Respiratory zone?
Includes structures directly involved in gas exchange
Where does the Respiratory zone begin?
Begins where terminal bronchioles of conduction zone join a respiratory bronchiole (smallest type of bronchiole)
What do Respiratory bronchioles lead to?
They lead to an alveolar duct opening to a cluster of alveoli
What is an Alveolar duct?
Tube composed of smooth muscle and connective tissue, opens to cluster of alveoli
What are Alveolus?
One of many small, grape-like sacs attached to alveolar ducts
What are Alveolar Sacs?
- Cluster of many individual alveoli responsible for gas exchange
- ~200 μm in diameter
- Elastic walls allow alveolus to stretch during air intake (increases surface area for gas exchange
How do Alveoli connect to one another?
By alveolar pores that maintain equal air pressure throughout alveoli/lung
What are the 3 major types of alveolar cells?
Type 1
Type 2
Alveolar Macrophages
What type of Alveolar cells make up 97% of alveolar surface area, are 25 nm (thin), composed of squamous epithelial cells that border capillary membrane, and highly permeable to gases?
Type 1 Alveolar cells
What type of Alveolar cells are interspersed among type I cells, secrete pulmonary surfactant (Substance composed of phospholipids/proteins that reduces surface tension/friction of alveoli)?
Type 2 Alveolar cells
What type of Alveolar cells roam alveolar wall, phagocytic cell removes debris/pathogens?
Alveolar Macrophages
What is the Respiratory membrane?
0.5 μm thick, consists of the alveoli and capillary membranes, allows simple diffusion of gases (where gas exchange happens)
What is Asthma?
A chronic disease affecting children/adults; characterized by airway inflammation, excessive mucus secretion, edema and bronchospasm (constriction of bronchioles)
Describe the shape of the lungs.
Pyramid-shaped, paired organs, connected to trachea by right and left bronchi
What are the lungs bordered by inferiorly?
The Diaphragm
What is the Diaphragm?
A dome shaped muscle
What are the lungs enclosed by?
Pleurae
Which lung is bigger?
The right lung.
Right lung is shorter and wider, left lung occupies a smaller volume
What is the Cardiac notch?
Indentation on surface of left lung (allows space for heart)
Describe the location of the lungs?
Apex of lung is in superior region
Base of lung is near diaphragm
Costal surface borders the ribs
Mediastinal surface faces midline
How many lobes does each lung have?
Right = 3
Left = 2
What separates the lobes of the lungs?
Fissures
What is the Bronchopulmonary segment?
- Division of a lobe
- Each lobe houses multiple bronchopulmonary segments
- Each segment receives air from its own tertiary bronchus and has its own arterial supply
What are Pulmonary Lobule?
- Subdivision formed as bronchi branch into bronchioles
- Each lobule receives its own large bronchiole that has multiple branches
- Has interlobar septum-separates lobules from one another
What is Pulmonary Circulation?
Contains deoxygenated blood, travels to lungs where erythrocytes (RBCs) pick up O2 to be transported to tissues throughout body
What is the Pulmonary Artery?
Arises from pulmonary trunk, carries deoxygenated blood to alveoli
One arteriole and venule drain and supply one….
Pulmonary lobule
Bronchoconstriction is controlled by which nervous system?
Parasympathetic
Bronchodilation is controlled by which nervous system?
Sympathetic
Reflexes such as coughing, ability of lungs to regulate O2/CO2 levels also result from the….
Autonomic nervous system
What is the Pulmonary Plexus?
Region on the lung root formed by entrance of nerves at the hilum; Nerves follow bronchi in lungs and branch to innervate muscle fibers, glands, blood vessels
What is the Pleura?
A serous membrane surrounding each lung
What are the R&L Pleurae separated by?
The Mediastinum
What are the 2 layers of the Pleura?
Visceral and Parietal
What is the Visceral pleura?
Superficial to lungs and extends into/lines lung fissures
What is the Parietal pleura?
Outer layer, connects to thoracic wall, mediastinum, diaphragm; Visceral/parietal pleura connect to each other at the hilum
What is the space between the visceral and parietal layers?
The Pleural cavity
What are the 2 main functions of the Pleura?
- Produce pleural fluid
- Create cavities that separate major organs
Where is Pleural Fluid secreted?
It is secreted by mesothelial cells from both pleural layers.
What is the function of Pleural Fluid?
Lubrication and reducing friction between the two layers, create surface tension to help maintain position of the lungs against the thoracic wall.
Why does the Pleura separate major organs?
Prevent interference due to movement of other organs and prevents the spreading of infection
What is the function of the Conducting zone?
Provides route for incoming/outgoing air, Removes debris and pathogens, Warms/humidifies incoming air, Aids in detecting odors, Metabolizing airborne carcinogens
What is the function of the Respiratory zone?
Gas exchange, where respiration occurs
What is the function of the Goblet cells?
Produce mucus to trap debris
Why does the Left Lung only have 2 lobes?
Because of the space required for the heart
What kind of blood does the pulmonary artery contain?
Oxygenated OR Deoxygenated
Pulmonary artery is the only artery in the body that contains deoxygenated blood.
What kind of blood does the pulmonary vein contain?
Oxygenated OR Deoxygenated
Pulmonary vein is the only vein in the body that contains oxygenated blood.
What is Pulmonary Ventilation?
Pulmonary ventilation is the act of breathing (movement of air into and out of lungs)
What are the 3 mechanisms that drive Pulmonary Ventilation?
- Atmospheric pressure (Patm)
- Air pressure within alveoli, called intra-alveolar pressure (Palv)
- Pressure within pleural cavity, called intrapleural pressure (Pip)
Inspiration (air in) and expiration (air out) is dependent on what?
The differences in pressures between the atmosphere and the lungs
What is Boyle’s Law?
P1V1=P2V2
What happens if volume or pressure, increases or decreases?
If volume increases, pressure decreases
If volume decreases, pressure increases
What is Atmospheric Pressure?
Amount of force exerted by gasses in the air surrounding any given surface, such as the body.
What does a negative pressure mean?
Negative pressure=pressure lower than atmospheric pressure
What does a positive pressure mean?
Positive pressure=pressure higher than atmospheric pressure
How is a pressure that is equal to Atmospheric pressure expressed?
As 0 (zero)
What is Intra-alveolar Pressure?
Pressure of air within the alveoli.
(Also known as intrapulmonary pressure)
When does Intra-alveolar Pressure change?
During different phases of breathing
T or F: intrapulmonary pressure of alveoli always equalizes with atmospheric pressure due to the alveoli being connected to the atmosphere via tubing of the airways.
True
What is Intrapleural Pressure?
Pressure of air within pleural cavity, b/w visceral and parietal pleurae
T or F: Intrapleural pressure is always lower than (or negative to) intra-alveolar pressure, meaning it is negative to atmospheric pressure.
True
What causes the Negative Intrapleural pressure?
Negative pressure is caused by competing forces within thorax
What is Transpulmonary pressure?
The difference between intrapleural and intra-alveolar pressures
What does the Transpulmonary Pressure do?
Determines the size of the lungs.
High pressure = larger lung
In addition to pressure, breathing also depends on…
The contraction/relaxation of muscle fibers of diaphragm and thorax
Are the lungs passive or active during breathing?
Passive
What causes the active action of breathing?
Contraction/relaxation of diaphragm and external intercostal muscles (b/w ribs)
What other lung characteristics that influence ventilation?
Resistance
Thoracic wall compliance
What are the 2 major steps that make up Pulmonary Ventilation?
Inspiration
Expiration
What is the Respiratory cycle made up of?
1 sequence of inspiration and expiration
Rank the 3 pressures of Pulmonary Ventilation in order of positive to negative to atmospheric.
Atmospheric
Intrapleural
Intra-Alveolar
Atmospheric > Intra-Alvelolar- Intrapleural
What are the 2 muscle groups used during Inspiration?
The diaphragm and the external intercostal muscles
How does the Diaphragm work during Inspiration?
Contraction of the diaphragm; it moves inferiorly toward abdominal cavity, increasing thoracic cavity/space for lungs
How does the External Intercostal Muscles work during Inspiration?
Contraction of external intercostal muscles; it moves ribs upward/outward causing rib cage to expand increasing volume of thoracic cavity
How does Pleural Fluid aid in Inspiration?
Its adhesive force forces the lungs to stretch and expand
Is Inspiration an Active or Passive process?
Active
Is Expiration an Active or Passive process?
Passive
What is Expiration?
The elasticity of lung tissues causes lung to recoil as diaphragm and external intercostal muscles relax following inspiration
What are the 4 types of breathing?
Quiet
Diaphragmatic
Shallow
Forced
What is Quiet Breathing?
(eupnea);
Occurs at rest, does not require cognitive thought of individual, diaphragm and intercostals contract
What is Diaphragmatic Breathing?
Only diaphragm contracts, air passively leaves as diaphragm relaxes
What is Shallow Breathing?
(costal breathing); Contraction of intercostal muscles, air passively leaves as intercostals relax
What is Forced Breathing?
(hypernea);
Occurs during exercise/actions that require manipulation of breathing (singing)
What muscles are involved in Forced Breathing?
Diaphragm, intercostals, accessory muscles
During inspiration = scalenes
During Forced expiration = obliques, internal intercostals
What does Boyle’s law tell us about the relationship between pressure and volume of a gas?
As volume increases-pressure decreases; as volume decreases-pressure increases
What is normal atmospheric pressure (i.e. what is the measurement)?
760mmHg
Contraction and relaxation of what muscle fibers controls normal breathing?
External intercostal muscles
Internal intercostal muscles
Trapeziums muscle
Diaphragm
External Intercostal Muscles
Diaphragm
What is Respiratory Volume?
Various volumes of air moved by the lungs in the respiratory cycle
What are the 4 types of Respiratory Volumes?
Tidal
Expiratory Reserve
Inspiratory Reserve
Residual
What is Tidal Volume (TV)?
Amount of air entering lungs during quiet breathing (500ml)
What is Expiratory Reserve Volume (ERV)?
Amount of air you can forcefully exhale past a normal tidal expiration (up to 1200mls for males)
What is Inspiratory Reserve Volume (IRV)?
Produced by deep inhalation, past tidal inspiration; is the extra volume that can be brought into lungs during forced inspiration
What is Residual Volume (RV)?
Air left in the lungs if you exhale as much air as possible; makes breathing easier by preventing alveoli collapse
What is Respiratory Capacity?
Combination of two or more selected volumes, further describes amount of air in lungs during a given time.
What are the 4 types of Respiratory Capacity?
Total Lung (TLC)
Vital (VC)
Inspiratory (IC)
Functional Residual (FRC)
What is Total Lung Capacity (TLC)?
Sum of all lung volumes (TV, ERV, IRV, RV), represents total amount of air person can hold in lungs after forceful inhalation (6000mL for males, 4200mL for females)
What is Vital Capacity (VC)?
Amount of air a person can move into/out of lungs; sum of all volumes (TV, ERV, IRV) except residual volume (4000-5000mL)
What is Inspiratory Capacity (IC)?
Maximum amount of air that can be inhaled past normal tidal expiration; is the sum of tidal volume and inspiratory reserve volume
What is Functional Residual Capacity (FRC)?
Amount of air remaining in lung are normal tidal expiration; is the sum of expiratory reserve volume and residual volume
What is Anatomical Dead Space?
Air that is present in airway that never reaches alveoli or participates in gas exchange
What is Alveolar Dead Space?
Air found within alveoli that are unable to function (i.e. those affected by disease or abnormal blood flow)
What is Total Dead Space?
Anatomical dead space AND alveolar dead space together (Represents all air in the respiratory system not being used in gas exchange)
What are the major brain centres involved in Respiration?
Medulla oblongata
Pontine respiratory group (in the pons)
What does the Medulla Oblongata do for the Respiratory system?
Helps to establish respiratory rhythm
What is the Ventral respiratory group (VRG)?
Involved in maintaining breathing rhythm by stimulating diaphragm/external intercostal muscles to contractinspiration
What happens when VRG activity ceases?
Diaphragm/external intercostals aren’t stimulated resulting in relaxation of muscles = expiration
What is the Dorsal respiratory group (DRG)?
Receives input from sensors such as lung stretch receptors and peripheral chemoreceptors, then communicates to the VRG to modify respiratory rhythm
What does the Pontine Respiratory group do?
Helps to establish respiratory depth & rate
What centres make up the Pontine Respiratory group?
Apneustic center
Pneumotaxic center
What is the Apneustic center?
Double cluster of neuronal cell bodies that stimulate neurons in the DRG; controls depth of inspiration (esp. for deep breathing)
What is the Pneumotaxic center?
Network of neurons that inhibits activity of neurons in the DRG; allows relaxation after inspiration controlling rate
