UNIT 3 Flashcards
Ventilation
Gas movement into and out of the lung. (Inhalation and Exhalation).
Different types of gas exhange
Diffusion, Pulmonary and Tissue.
Pulmonary Gas exchange
aka external respiration
Tissue gas exchange
aka internal respiration
Gas transport
gas movement in blood (to the tissues and from the tissues).
Neurologic Control
Regulation of ventilation and thus gas exchange. (Brain, nervous system).
Components of the Upper Airway
Nose, oral cavity, pharynx, larynx.
Larynx
transitional airway (in middle).
Primary functions of Upper Airway
Conduction of air, conditioning of air, preventing foreign material from entering lung, speech (vocal), and smell. No gas exchange occurs.
External nose structure
Anterior nares (choanae), external nares, alar cartilage (wing, lateral structure), septal cartilage (divides into 2 cavities).
Internal Structure of the nose
Choana, turbinates, olfactory region.
Turbinates
bony lateral projections. (superior, middle and inferior location).
What type of flow occurs at the turbinates and what does it help do?
turbulent flow occurs, and it helps get particles out of the air.
Meati
Internal structure of nose, air passageways. formed by the turbinates.
Paranasal Sinuses
Arranged in pairs, drain into nose through openings behind turbinates. Named for bones. (frontal, ethmoid, maxillary, and sphenoid).
Paranasal Sinuses function
lighten skull, resonance chamber for speech.
Two palates
Hard palate and soft palate
Hard Palate
palatine bone. anterior portion, bony.
Soft Palate
posterior portion, tissue.
Uvula
located at palate, terminal end.
Congenital
present at birth
Posterior Nares
opening from nasal cavity into pharynx.
Chanal Atresia
congenital defect in newborns at posterior nares, opening covered by tissue or bone, surgical emergency to open the passageway.
Mucosa (anterior).
Membrane, tissue covering inside of nose. Anterior 1/3. Squamous, nonciliated epithelium.
Mucosa (posterior)
Posterior 2/3. pseudostratified, ciliated, columnar epithelium. Contains numerous serous mucous glands.
Vasculature
Internal and external carotids, nasal mucosa highly vascularized. Increased in blood flow results in congestion and swelling.
Innervation of the nose
7th cranial nerve and 5th cranial nerve.
7th Cranial Nerve
motor innervation to muscles of external nose.
5th cranial nerve
sensory nerve to mucosa.
Primary functions of Nose
Humidification, heating, and filtration.
Secondary functions of Nose
Olfaction, Phonation.
Humidification
1,000 mL/day. Evaporation of H2O from mucous/serous secretions.
75-80% RH body temp.
Heating
heat exchange, heat conduction from mucosa, profuse vascularization.
Filtration
vebrissae, mucocilliary action, and soluble foreign gases and vapors.
Vebrissae
large, coarse hairs inside of external nares. Large particles impact.
Mucociliary Action
mucus blanket, cilia.
top layer of mucous
gel layer, sticky layer.
bottom layer of mucous
sol layer, watery layer.
How many cm do cilia move per hour?
12 cm per hour, 120 mm per hour.
Structure of Pharynx
space behind oral and nasal cavities. has subdivisions.
Subdivisions of Pharynx
Nasopharynx, oropharynx, laryngopharynx.
Nasopharynx parts
eustachian tube, phayngeal tonsils.
Nasopharynx
receives air from the nasal cavity
Eustachian Tube
auditory tube, equalizes air pressure, drainage of fluid from middle ear.
Pharyngeal Tonsils
AKA adenoids, enlargement=otitis media
Adenoids
block drainage of middle ear causing infection
Oropharynx functions
Receives food from oral cavity, receives air from oral cavity and nasopharynx. Includes the palatine tonsils and lingual tonsils.
Laryngopharynx
known as hypopharynx, receives food and air from oropharynx.
Air=
larynx
Food=
esophagus
Motor nerve=
pharyngeal muscles
Larynx structure
anterior part of neck, level of 4th, 5th and 6th cervical vertebrae, glottis.
what is the glottis
opening between the vocal cords, opening in larynx, narrowest point of upper airway in adults.
Where is the narrowest part for newborns
below the glottis.
Cartilage
connected by muscles, membrane.
Thyroid cartilage
largest cartilage in the larynx, known as adam’s apple, larger in males than females.
Cricoid cartilage
complete ring, narrowest point in newborns/small children. below the glottis.
Cricothyroid membrane
ligament between cricoid and thyroid cartilage. can provide emergency airway access if needed.
Arytenoids
significant role in vocal cord movement.
Epiglottis
attached to thyroid cartilage, covers glottis during swallowing.
Vocal cords
ligamentous, extend from arytenoids to thyroid.
Function of Larynx
gas conduction, protect lower airway, coughing, and speech.
The lower airway protects what in the larynx?
epiglottis
Are vocal cords important for coughing?
yes
Swallowing
involuntary and voluntary responses.
Voluntary response of swallowing
food moves from mouth to pharynx.
Involuntary response to swallowing
tongue elevates (seals mouth), soft palate elevates (seals nasopharynx), epiglottis folds back (blocks glottis).
Coughing
Voluntary and involuntary responses.
Involuntary response to coughing
stimulus, cough receptors (larynx, trachea, carina, and larger bronchi).
Phase of coughing: Deep inspiration
glottis closes, epiglottis, cords.
Phases of coughing
abdominal muscles contract (increase intrapulmonary pressure) expulsion (sudden opening of glottis). 100 mph.
Pharyngeal Reflex
“gag reflex” “swallowing reflex”, protective reflex.
9th cranial nerve
sensory
10th cranial nerve
motor
Laryngeal Reflex
“laryngospasm” vocal cords snap shut. Vagus nerve.
Vagus Nerve
sensory and motor. Vagovagal.
Tracheal Reflex
Cough reflex. Vagovagal.
Carinal Reflex
Cough reflex (nerve cough receptors in carina). Vagovagal. Lower respiratory tract.
What order do you lose your reflexes in?
Descending order. (top to bottom).
How do you gain your reflexes back in?
Ascending order. (bottom to top).
Tracheobronchial Tree subdivisions
large airways, and small airways.
Large airways are made up of
bronchi
Small airways are made up of
Bronchioles. no cartilage.
Tracheobronchial Tree
System of conducting tubes.
What does the tracheobronchial tree allow
gas to move to and from lung parenchyma, and gas exchange.
Epithelium
pseudostratified, ciliated, columnar epithelium. Numerous mucous and serous secreting glands.
Lamina Propria
submucousa. Loose, fibrous. Contains blood vessels, lymphatic vessels, nerves. Network of smooth muscle.
Cartilaginous Layer
Varying amounts of cartilage. Cartilage disappears in tubes less than 1 mm in diameter.
Trachea adult length
11-13 cm/ 1.5-2.5 cm diameter
Carina
area where trachea branches into 2 mainstem bronchi.
Position of trachea
directly infront of esophagus, flanked by great vessels of neck.
Trachea
16-20 C shaped cartilages. Posterior wall composed of flat membrane, separated from anterior esophogeal wall by loose connective tissue.
Main stem bronchi length
1 cm diameter
Main stem bronchi structure
trachea divides into right and left main stem bronchi. similar to trachea biologically.
Right main stem bronchus
wider, shorter than left side. appears to be an extension of trachea. does not branch off at such a heavy angle as left. 20-30 degree angle.
Left main stem bronchus
Narrower, longer than right. looks more like branch than continuation of trachea. 45-55 degree angle.
Lobar Bronchi
Right main stem bronchus divides into 3 lobar bronchi.
Upper, Middle, Lower.
Left main stem bronchus divides into 2 lobar bronchi. Upper and Lower.
Cartilage lose horseshoe shape. provides rigidity.
Segmental Bronchi
Lobar bronchi branch into segmental bronchi. Name according to lung segments they supply.
Sub-segmental Bronchi
4-11 divisions from trachea. Diameters decrease from approx. 4 mm to 1 mm.
Function of arrangement of sub-segmental bronchi
number of airways increase with each generation. Total cross sectional area of respiratory tract at each level increases.
Bronchioles diameter
< 1-2 mm
Bronchioles
total cross sectional area increases. resistance to air flow in small airways is individually greater, but overall resistance of network is less. It is believed velocity of air steps. By the time you get to the last terminal bronchiole gas steps and gets the lungs by diffusion.
Law of Continuity
Fluids. As cross sectional area increases of a branching network of tubes, the velocity decreases.
Primary Lobule
functional unit of gas exchange in the lung.
Bronchioles cont.
contribute 10-20% total airway resistance due to the network being bigger. contributes to blood supply, arterial circulation.
Where is most resistance?
In the large airways.
Terminal bronchioles
last airway of tracheobronchial tree. diameter avg. 0.5 mm. Mucus glands and cilia disappear.
Terminal bronchioles mucus production?
mucus at this level is produced by Clara cells.
130,000 terminal bronchioles, bring air to primary lobule.
Clara cells
glands in epitheleal layers, produce mucus, look different than goblet cells under microscope.
how much % is the normal amount you inhale?
30-40% of tidal volume is the amount you normally inhale.
Mucus Blanket (Respiratory Tract).
Rate of mucus production= 100 mL/day. Continuous, uninterrupted covering. (layer over the most you swallow).
Function of Secretions
diminish/regulate H2O loss, protect cells and mucus membranes, mucociliary clearance mechanism, bacteriocidal or static activity.
What does excessive production of mucus mean?
infection, allergy, dehydration, chemical irritation, increased gas flow/velocity.
Cystic Fibrosis
defect that occurs in the pancreas, effects excretion glands in the lungs. (viscous mucus) affects water and ion exchange.
Cilia
lie within sol layer. when beat the tip of cilia stick out of gel layer and help move mucus along.
Gland
produce mucus that collects above epithelial cells.
Mast cells
involved in an allergic response that occurs in the airway.
Lung Parenchyma
2 functions: gas exchange and nourishing the tissue.
Types of Alveolar cells
Type I, Type II, and Type III.
Type I cells
epithelium, most of the structure.
Type II cells
produce a chemical surfactin. (surface-active agent). reduces surface tension in alveoli, helps so alveoli does not collapse.
Type III cells
alveolar macrophages, ingest foreign material, have mobility, and deposit foreign material.
Primary Lobule
Diameter 3.5 mm, supplied by single pulmonary arteriole.
Alveolar Ducts
arise from respiratory bronchioles, walls composed of alveoli separated by septal walls, about 1/2 alveoli arise from ducts, about 35% exchange, other 65% would be in the sacs.
Alveolar sacs
last generation of airway, functionally same as alveolar ducts, but are blind passages (dead ends), sacs exist in clusters of 15-20 with common walls, 50% alveoli, 65% gas exchange.
Macrophages
Type III alveolar cells, arise from bone marrow or Type II cells.
Surfactant
Fluid, continuously produced by Type II cells, 1/2 life of 24 hr. Detergent-like substance, chemically a phospholipid (lecithin, primary one), reduces surface tension in lungs, (prevents alveolar collapse).
Components of AC membrane
surfactant, alveolar epithelium, interstitium, and capillary endothelium.
Right lung
55% by weight and volume.
3 Lobes
Transverse and Oblique Fissures
Right lung lobes
Upper- apical, posterior, anterior.
Middle- Lateral, medial
Lower- Superior, Anterior basal, medial basal, lateral basal, posterior basal.
Left Lung
45% by weight and volume
2 Lobes
Oblique fissure
Left lung lobes
Upper- apico-posterior, anterior, superior lingular, inferior lingular.
Lower- superior, antero-medial basal, lateral basal, posterior basal.
Albuterol
stimulates sympathetic system.
Aorta- systemic circulation
right atrium.
Arteries systemic circulation
capillaries –> veins
Arteries
conduct blood away from heart
Capillaries
site of gas exchange
Veins
conduct blood back to heart
Bronchial circulation
nutritional supply to T-B tree, bronchial artery (1st branch off descending aorta, enters lung at hilum.)
Bronchial veins
anatomical shunt, mixing of oxygenated with unoxygenated blood.
PaO2 can never be as high as PAO2
Pulmonary circulation Pulmonary artery ->
left atrium
Pulmonary circulation pulmonary artery –>
pulmonary capillaries –> pulmonary veins
Functions of pulmonary circulation
gas exchange, nutritional supply to lung parenchyma.
Resistance formula
R= deltaP/V (flowrate)
Lymphatics
drain fluid from lungs,
Ventilation Perfusion relationship in lungs
ratio of amount of ventilation to amount of blood flow. V/Q ratio.
Normal V/Q ratio
4/5=0.8
4 liters ventilation to 5 liters perfusion.
Alveolar Units: Normal unit
normally ventilated, perfused.
Alveolar Units: Dead space unit
ventilated, not perfused.
Alveolar units: shunt unit
perfused, not ventilated.
Alveolar Unit: Silent Unit
neither ventilated, nor perfused.
V/Q in Apices
Better ventilated than perfused. PAO2 increases. (more O2 coming into alveoli).
PACO2 decrease. (more CO2 leaving alveoli, less CO2 coming into alveoli.
V/Q in Bases
Better perfused than ventilated. decrease PAO2. increase PACO2
Visceral pleura
lines outside of lungs
Parietal pleura
lines inside of rib cage
potential space for air, blood, pus.
normally contains few drops of lubricating type fluid.
nemothorax
air in thorax
hemothorax
blood in thorax
empymea
puss in thorax
What are the lungs separated by?
mediastinum
bony part of ribs
costae
How many pairs of ribs are there?
12 pairs, 7 attached to the sternum
Thoracic cage
cone shaped.
protects C-P organs, supports shoulder attachment for muscles (upper limb, vertebrae, skull).
Sternum
composed of three flat elongated bones. 3 parts: manubrium, body, xiphoid process.
addlexrisis
collapsed lung
Rib 11-12
floating ribs. they float inward to provide protection for the kidneys. retroparitheal space.
Costae condral junction
where bony rib meets cartilage from sternum
Muscles of Ventilation
responsible for changing size (volume) of thorax. Diaphragm, Intercostasl muscles, accessory muscles, abdominal muscles.
Accessory muscles help during
inspiration
Abdominal muscles are muscles are
expiration
Diaphragm
separates thoracic and abdominal cavities. made of two “hemidiaphragms.
dome shaped, major muscle of ventilation
What happens with the diaphragm during contraction?
causes each half to be pulled down, thus increasing volume of thorax. decrease pleural space.
Intercostal muscles
2 layers of muscle fibers connecting ribs. External and internal.
Contraction of External Intercostal muscles
pulls up rib below, upward and outward. Increases A-P diameters and transverse diameter of thorax.
Contraction of Internal intercostals
pulls down rib above.
Accessory Muscles
Elevate and stabilize chest wall. capable of providing reasonable degree of inspiratory activity. muscles of inspiration.
Major Accessory Muscles
Sternocleidomastoid, Pectoralis Major, Trapezius.
Abdominal muscles
Muscles of expiration
Normally passive.
occurs due to elastic recoil of lung.
Abdominal muscles play role in active expiration
external oblique, internal oblique, rectus abdominus, transverse abdominus.
