Respiratory System Flashcards
anticlinal vertebrea
11th thoracic vertebrae,, straight vertical, identifying landmark on radiographs
diagphragm
chief inspiratory muscle, innervated by C3-C5, (phrenic nerve)
thorax vs thoracic cavity
thorax is all structure from 1st to 13th rib, even those in the abdomen
What are the cranial and caudal boundaries of the diaphragm?
7th to 13th rib
significance of the cupula?
The pleural sac extends beyond the first rib and injury to this area can lead to collapse of the pleural cavity and collapse of lung
pleural cavity
potential space between visceral and parietal/costal pleura
directionality of the external and internal intercostal muscles
external intercostal is caudoventral internal intercostal is cranioventral
Muscles of expiration
expiration is normally passive but in disease cases the internal intercostal muscles can assist expiration (Heaves in horses, causing heaves line)
function of external intercostal muscle
inspiration
when should the thymus regress by?
6 months
boundaries for Auscultation of the lungs
triangle between 5th to 11th rib
Where is the proper location to tap for thoracocentesis?
7th to 10th intercostal space, cranial to ribs not caudal to avoid blood vessels, angle down towards body wall so you don’t hit the lungs
Components of the conducting portion of the respiratory system
nose and mouth, nasopharynx, larynx, trachea, bronchi, bronchiole, terminal bronchiole,
components of the respiratory portion of respiratory system
respiratory bronchiole, alveolar duct, alveolar sac, alveolus
significance of the conducting portion
contributes to dead space. When dead space is increased, gas exchange becomes more difficult
TRE on turbinate bones
coiled bones slows down the air to create laminar (slow) flow to warm it and add moisture
(air should be humidified with endotracheal tube)
TRE
typical respiratory epithelium: pseudostratified ciliated columnar epithelium
occupies bulk of the respiratory system
how might heartworms impact breathing?
Because the heart is closely associated with the lungs, heartworms can cause disrupted breathing
costodiaphragmatic recess
area where the longs will not go even when fully extended
line of pleural reflection
where the pleura turns back on itself, location differs depending on species
Cell Junctions
Tight junctions: seal
Adherens: attachment (contact inhibition)
Desmosomes: hold cells together (lightly)
Hemidesmosome: hold cells lightly to basal lamina
clinical significance of the cell junctions?
Pathogens and autoimmune diseases affect the cell junctions
contact inhibition
adherens junctions, cells grown in a lab will stop growing if they are touching
How do hydrogen sulfide and ammonia damage the epithelium?
disruption of tight junctions
5 cell types and functions in TRE
goblet cells secrete mucus, basal cells repair, ciliated cells move mucus/ escalator, neuroendocrine: sensing and growth brush cells: connected with trigeminal nerve endings to activate sneezing and sense fumes
structure of goblet cells
mucus located toward apic side, nucleus pushed toward the basal side, microvilli present
neuroendocrine cells
no ducts, produce hormones transported by blood flow
how does goblet cell concentration change in response to an irritant (like smoking)?
Goblet cells increase for more mucus production
microscopic anatomy of nasal vestibule
keratinized stratified squamous epithelium with hair transitioning to non keratinized, hyaline cartilage, serous and sweat glands, hair follicles, few nerve fibers, blood vessels and immune cells in propria submucosa
microscopic anatomy of nasal cavity
(respiratory portion but no gas exchange) TRE responsible for humidification and warming with mucus secreting goblet cells,
thin walled veins and glands present
alpha adrenergic stimulation via sympathetic stimulation (constriction)
nerves, lymphatic nodules
P450 enzymes and detoxification (formalin)
Trigeminal and autonomic efferent innervation
microscopic anatomy of the olfactory region
thick high, pseudostratified epithelium
olfactory cells with bipolar neurons
supporting cells, basal cells (tight junctions),
20-30 cilia per cell longer than in TRE, nonmotile, have receptors for odorant molecules
Olfactory/ Bowman’s glands in propria submucosa
lipofuscin pigmentation makes this region darker
absence of goblet cells because mucous is antagonistic to olfaction,
serous glands in lamina propria, abundant olfactory nerves
supporting cells
sustentacular cells, protective, glial like, occluding/ tight junctions
oval shaped nuclei compared to rounder nuclei of olfactory cells
How is the olfactory anatomy different in dogs?
More olfactory epithelium, cribriform plate has more holes
Bowman’s gland
located in propria submucosa, initiates olfaction by producing watery secretion that solubilizes odorant molecules for the receptors on the cilia so the action potential can be initiated, these glands also cleanse the receptors for new smells
vomeronasal organ structure
joins the incisive duct and opens caudal to the central upper incisors, located in the mucosa of ventral portion of nasal septum, tubular blind-ended and paired structure
vomeronasal duct is crescent shaped
J-shaped hyaline cartilage support,
opens at incisive papilla,
medial epithelium containing neuro-sensory cells, sustentacular cells, basal cells,
vomeronasal gland,
Flehmen’s response
means bearing upper teeth in German to sense pheromones and urine particles in the air
functions of vomeronasal organ
chemoreception of liquid borne substances like pheromones, sexual behavior, maternal instinct, fetal interaction with amniotic fluid.
How does the mucociliary escalator work?
the cilia bend when moving backward so that the mucus moves in only one direction
structure of cilia
9 doublets of microtubules surrounding a central doublet Nexi protein binds tubules together dynein arm (inner and outer) have sliding motion to propel cilia, fueled by ATP
primary ciliary dyskinesia
PCD, immotile ciliary syndrome/ Kartagener syndrome
Respiratory and middle ear infections, mucus gets in middle ear canal and causes ear infections, situs inversus totalis, situs ambiguous or heterotaxy syndrome, reproductive failures, rhino-sinusitis, bronchitis
defect in genes coding dynein protein seen in some dog breeds,
autosomal recessive genetic disorder
absence of dynein arm leads to defective or absent ciliary motility
diagnosed electron microscopy of bronchial biopsy
advise not to use in breeding because there is no effective treatment
diagnosis of situs inversus
auscultation and palpation
clinical conditions impacting the pharynx and larynx
collapse of pharynx, long soft palate of horses can cover the epiglottis in dorsal displacement of soft palate (DDSP), laryngeal hemiplegia
histology of nasopharynx and larynx
typical respiratory epithelium, propria submucosa: loose connective tissue, seromucous glands
histology of epiglottis and vocal folds
non keratinized stratified squamous transitioning to TRE at trachea, glands are absent, elastic cartilage
Why do the vocal folds have stratified squamous epithelium?
Because of the wear and tear that occurs in this area during vocalization
What type of epithelium is present at the alveoli?
simple squamous
Are goblet present in alveolar tissue?
No because mucus would inhibit respiration like during pulmonary edema, disappear in bronchioles
histology of trachea
TRE, C-shaped hyaline cartilages, trachealis muscle, longitudinal elastic fibers, most glands, seromucous glands, tunica adventitia (loose connective tissue), very little smooth muscle, goblet cells
trachealis muscle
allows flexibility as food moves along the esophagus next to it, supplies support, trachealis can be slightly inside or inside depending on species
composition of hyaline cartilage
chondrocytes, matrix, and type II collagen fibers
What happens when cartilage is defective?
tracheal collapse, presenting with goose honk coughing, common in toy breeds, but can occur in large dogs and cats, collapse inside thoracic cavity, 50% collapse of trachea increases airway resistance by 16 times the normal, medical management is temporary fix, surgical treatment is best option by placing a stent.
histology of bronchi
TRE, C shaped hyaline cartilage has broken into plates/pieces, goblet cells are present, many mixed glands, more smooth muscle, more associated blood vessel, pulmonary arteries and veins,
histology of bronchiole
simple columnar to simple cuboidal (ciliated and non ciliated), cartilage and glands absent, few goblet cells, most smooth muscle which is arranged in circular and oblique fascicles
Club cells
bronchiolar exocrine cells, club shaped, devoid of cilia, secrete glycosaminoglycan, metabolize xenobiotics like cytochrome P450, club cell secretory protein (similar to surfactant) is a biomarker/ marker for injury of these tissues, contain tryptase and activate hemagglutinin of Influenza A, act as stem cell for bronchiolar epithelium
surfacant
produced by type II alveolar cells
pulmonary trunk
from right ventricle dividing into right and left pulmonary artery and enter the lung at the hilus. Follows the branching of the major airways so visible in lung sections. Pulmonary veins go away from alveoli to heart
Pulmonary artery blood has low pressure from right side of heart but bronchial artery is from left side of heart has higher pressure like the systemic pressure
nutritional vs functional blood
Functional blood goes from right atrium and returns to left atrium
Nutritional blood includes bronchial artery to supply the cells of the major airways. Comes from bronchoesophageal artery from the aorta. then shunts to the pulmonary vein
Capillaries don’t need nutritional blood, they just use normal blood gas exchange
pulmonary artery
thin and carries deoxygenated blood. low pressure compared to systemic arteries, both internal and external elastic laminae
bronchial artery
thick walls, carries oxygenated blood, has only internal elastic laminae
pulmonary vein
carry oxygenated blood to left atrium, has only external elastic laminae and thinner tunica media
6 to 8 in number depending on the number of lung lobes
pulmonary arterial hypertension
can be due to chronic hypoxia or inflammation, seen in humans and animals, hypertension caused by effusion of pulmonary vessels and arteries become occluded.
importance of lymphatics
left atrioventricular valve defect could back up blood into pulmonary vein, lymphatic remove extra fluid, blood cells are not usually seen in lymphatics
terminal bronchiole
simple columnar (ciliated and nonciliated) no glands and no cartilages, smaller than normal bronchiole
respiratory bronchiole
simple cuboidal, few cilial and outpocketing of alveoli, continuation of terminal bronchiole, transitional portion between conducting and respiratory portion, both respiratory and conducting
alveoli
surrounded by capillaries, squamous (type 1) and cuboidal (type 2), alveolar macrophages
alveolar sac
several alveoli make one sac
pneumocytes
alveolar epithelial cells, type I is squamous and type II cuboidal
nucleated red blood cells
present in birds and reptiles, also in developing mammals and in cancer
blood gas exchange area
respiratory membrane, thickness of one hair
Type I Alveolar epithelial cells
squamous cells, only the nuclei are well seen, cover 95% of alveolar area, very thin blood-gas barrier, tight junctions hold them
Type II Alveolar epithelial cells
round and large cells, appear granular, produce surfactant, mostly in the corner of alveoli, cover 5% of the area, act as stem cells for Type I cells (most important ,function), can be phagocytic like macrophages
surfactant
produced by type II AEC, contained in osmiophilic lamellar bodies, disrupts surface tension to keep alveoli open
respiratory membrane
formed by fusion of basolamina of endothelial cells in capillaries and type I AEC
less than 1 micron thick, unless edema increases thickness and disrupts diffusion, thick in some areas and thin in others for support and for gas exchange
alveolar macrophages
found in the interstitial lumen, can have dark vacuoles with ingested toxins, can be viewed with a transtracheal wash/ lung labage, 20-80 microns in size, larger than type II AEC, do not confuse these, pulmonary intravascular macrophages are more inflamed compared to monocytes
pleura
thin, glistening, serous membrane, pleural cavity is very small with then film of fluid
pathologic conditions in pleura
pleuritis: inflammation, thoraco-abdominal or sholder pain), crackling noise as lungs rub against wall
pneumothorax and pleural effusion
primary vs secondary bronchi
secondary are within the lung
clinical significance of smooth muscle
causes heaves in horses, exploited for treatment of these conditions
Name the corresponding physiological concept for each clinical condition: Artificial ventilation pneumoconiosis lung fibrosis lung function tests gaseous anaesthetics asthma/ heaves in horses respiratory distress diagnosis sarcoidosis
Artificial ventilation: heat of vaporization
pneumoconiosis: turbulence
lung fibrosis: elasticity
lung function tests: gas laws
gaseous anaesthetics: vapor pressure
asthma/ heaves in horses: airway resistance
respiratory distress: surface tension/ surfactant
diagnosis: partial pressure
sarcoidosis: diffusion
respiration
O2 is acquired and CO2 is eliminated, involves forces to create a vacuum such as contraction of diaphragm and processes such as ventilation (movement of air), diffusion (blood gas exchange), transportation, and tissue delivery and return
What value can be used to assess if an endotracheal tube is placed correctly?
Use metabolism because all CO2 that is exhaled is a product of metabolism since there is none in the atmosphere
What is the atmospheric composition at sea level? Ames (1,000 ft above sea level)?
78% nitrogen, 21% oxygen, 0.93% argon, 0.04% CO2 and 1% H2O. These percentages are the same everywhere even though there is less total air at higher elevations
diffusion
blood-gas exchange, relies on concentration of gases across a membrane (concentration gradient) and the thickness of the membrane
hypoxia vs hypoxemia
hypoxia is less oxygen in the lungs or a particular region. Hypoxemia is less oxygen in the blood
path of upper respiratory tract
nares, nasal conchae, pharynx, larynx, trachea, principle bronchi
species with the most pliable nostrils
horse, helpful when exercising
Which anatomic feature is responsible for 90% of air humidification?
upper respiratory system
guttural pouches
extension of auditory tube in horses
what causes gunky eyes in the morning?
clogged nasolacrimal duct
Epithelium of epiglottis on oropharynx side vs tracheal side
stratified squamous epithelium (non-keratinized) on oral side and on the tip of the epiglottis. But epiglottis facing towards trachea is covered with TRE because of different locating needed different wear or breathing functions
inspiration
conduction of air, warm air to body temperature, add water vapor, saturate to 100% humidity, inhaled substances trapped in mucous
gutteral pouches
extension of auditory tube in horses
What causes gunky eyes in the morning?
clogged nasolacrimal duct
dry eye
can be caused by lost tears due to a nasolacrimal duct that is too large or open more
nasolacrimal duct
can be flushed
ways to improve respiration
mix oxygen with helium or nitrogen so the patient can breathe easier
surface area in airways
branching causes increased total surface area, and decreased resistance
blood supply to the alveoli
each alveolus is completely covered in capillaries
ventilation
Process of inhaling and exhaling so that the animal acquires O2 and eliminates CO2.
Involves: mechanical forces: respiratory muscles, pressure differences, negative and positive pressure ventilation
positive pressure ventilation
external force using a ventilator
tidal volume
volume of each breath, 0.5 L in humans
v (dot) E
minute ventilation, total volume of air breathed per minute
= tidal volume times respiratory frequency
respiratory frequency in humans
12-16 times per minute
dead space
VD, ventilation wasted, air that does not come in contact with the blood gas exchange area
1. equipment
2. Anatomic
3. Alveolar
Alveolar dead space adds to anatomic dead space
anatomic dead space can change eg. mucus
necessary so that air can be humidified but an increase in dead space ventilation is not desired
mixes fresh and used air so amount of oxygen delivered to the alveoli is less than that in the atmosphere, inhalation of old air so the concentrations of O2 and CO2 do not change very quickly
Assume that anatomic dead space is 150 mL
causes of alveolar dead space
hydrostatic pressure failure, embolus, emphysema, pre-capillary constriction due to tumor or foreign obstruction
emphysema
widening of alveoli and they don’t inflate and deflate properly, results in destroyed capillaries, can be caused by smoke, increased compliance
alveolar ventilation
not the same as minute volume/ minute ventilation
= total ventilation- dead space ventilation
physiologic (total) dead space
=anatomic dead space + alveolar dead space (functional dead space)
minute ventilation
=alveolar ventilation rate + dead space ventilation rate (important for thermoregulation)
tissue saturation of O2
can be represented by peripheral concentration of O2 in blood
rapid shallow breathing
ineffective because of less tidal volume and constantly reusing dead space air
v dot divided by q dot
ventilation- perfusion ratio
Ve
expired volume of gas
define these primary respiratory symbols:
P, V, S, F, Q, R, D
P: Pressure, partial pressure, or tension of a gas V: volume of gas S: saturation of hemoglobin with O2 F: fractional concentration of a gas Q: Blood volume R: Resistance D: Diffusing Capacity
bar above primary respiratory symbol
mean or mixed sample
prime sign after secondary symbol
end of a structure, eg. PE’CO2 refers to end tidal CO2
MRV
minute respiratory volume (total volume of gas moved in or out of airways and alveoli in 1 minute)
respiratory cycle
inspiration and expiration
respiratory pattern or waveform
smooth and symmetrical, horses have 2 phases of inspiration and 2 of expiration
complementary breathing cycle
sigh, deep rapid inspiration and expiration, not seen in horses, created using breathing bag
What happens to breathing pattern during peritonitis?
use of costal breathing
What happens to breathing pattern during pleuritis?
Just abdominal breathing
Which breathing pattern is the predominant one?
abdominal breathing
Eupnea
normal breathing
apnea
temporary cessation of breathing, can result in headache
tachypnea
fast breathing
bradypnea
slow breathing
dyspnea
labored and difficult breathing
hypernea
increased depth and rate
polypnea
rapid, shallow breathing (panting)
respiratory frequency
number of respiratory cycles/minute, excellent indicator of health status, varies depending on certain conditions
factors that increase respiratory frequency
pregnancy, digestive tract fullness, lying down, diseases (usually)
factors that decrease frequency
low temperature, sleeping
breath sound
due to air movement through the tracheobronchial tree (turbulent air flow)
adventitious sound
extrinsic to normal breath sounds, abnormal sounds superimposed on breath sounds, could be due to pleural disease or lung parenchyma, crackles due to edema or exudates, wheezes due to airway narrowing
Can you hear the sound of air passing through bronchioles?
no because the bronchioles offer almost no resistance unless there is a disease condition