Exam 2: Chap 23 Flashcards
two systems that cooperate to supply O2 and eliminate CO2?
cardiovascular and respiratory systems
what does the respiratory system provide for?
gas exchange
what does the cardiovascular system do?
transports the respiratory gasses (O2 and CO2)
respiration
the exchange of gases between the atmosphere, blood, and cells. takes place in four steps.
4 steps of respiration
pulmonary ventilation, external respiration, transport of respiratory gases, internal respiration
pulmonary ventilation
movement of air in and out of lungs so that alveoli are continuously refreshed
external respiration
gas exchange between air in lungs and blood in capillaries
transport of respiratory gases
O2 to tissues, CO2 from tissues
internal respiration
gas exchange between blood and tissue cells
what does the respiratory system consist of?
nose, pharynx, larynx, trachea, bronchi, and lungs
upper respiratory system
refers to the nose, pharynx, and associated structures
lower respiratory system
refers to the larynx, trachea, bronchi, lungs
conducting zone
consists of nose, pharynx, larynx, trachea, bronchi, bronchioles, respiratory muscle, and terminal bronchioles; functions to cleanse, humidify, and warm incoming air
respiratory portion
consists of respiratory, bronchioles, alveolar ducts, alveolar sacs, and alveoli; actual site of gas exchange
about how many alveoli are in your lungs?
enough to fill a tennis court
bony framework of the nose is formed by
frontal bone, nasal bones, maxillae, and is covered by hyaline cartilage
interior structures of nose; 4 critical functions?
specialized; 1. filter out foreign material 2. moistens and warms air that is inspired 3. location of olfactory receptors 4. resonating chamber to modify speech sounds
internal portion of nose contains what? and communicates with ________ and ________ through the _______.
3 conchae; paranasal sinuses and nasopharynx; internal nares (posterior nasal aperture)
3 conchae
superior (ethmoid bone), middle (ethmoid bone), inferior (inferior nasal conchae bone); function: increase mucosal surfaces of conchae exposed to the air and enhance turbulence in the nasal cavity
nasal cavity
inside of both the external and internal nose
histology of the mucous membranes lining the nasal cavity
respiratory epithelium; secretes premucin and enzymes called lysozyme. also secretes defensins, which are a natural antibiotic
defensins
natural antibiotic
paranasal sinuses located in what 4 cranial bones?
- ethmoid
- frontal
- sphenoid
- maxilla
function of sinuses
lighten skull, warm, and moisten incoming air, loaded with goblet cells
pharynx (throat)
muscular tube lined by a mucous membrane; 5 in long
anatomic regions of pharynx
nasopharynx, oropharynx, laryngopharynx
nasopharynx
functions in respiration only; contains the uvula, pharyngeal tonsils, eustachian tubes and respiratory epithelium
eustachian tube
equalizes pressure between atmosphere/internal ear AKA auditory tube
respiratory epithelium
ciliated pseudostratified columnar with goblet cells
oropharynx and laryngopharynx
function in digestion and in respiration; lined with non-keratinized stratified squamous epithelium
larynx (voice box)
passageway that connects the pharynx with the trachea
3 major functions of the larynx
- voice production
- patent (open) airway
- switching mechanism to send air/food in proper direction
what is the larynx lined with?
non-keratinized stratified squamous epithelium superior and respiratory epithelium inferior to the vocal cords
what does the larynx contain?
thyroid cartilage (Adam’s apple is the laryngeal prominence), epiglottis, cricoid cartilage
epiglottis
elastic cartilage, covered in taste buds, prevents food from entering the larynx
cricoid cartilage
what you cut into during a tracheotomy; connects the larynx and the trachea
what does the larynx contain to produce sound?
vocal ligaments that fold to form the true and false vocal cords, which produce sound
taunt vocal cords
produce high pitches
relaxed vocal cords
produce low pitches
what 5 other structures are necessary to convert sound (which originates from vocal fold vibrations) into recognizable speech?
- pharynx
- tongue
- soft palate
- lips
- teeth
trachea (windpipe) extends from where to where?
from larynx to primary bronchi
2 major functions of trachea
- provide a patent (open) airway
- further cleanse, warm, moisten, incoming air.
mucosa of trachea
respiratory epithelium: cilia of the epithelium beat in a wave like fashion towards the pharynx to sweep debris away from lungs
submucosa of trachea
connective tissue layer: glands produce premucin
adventitia or fibrosa
numerous C-shaped rings of hyaline cartilage (about 16-20)
trachealis muscle
smooth muscle whose contraction decreases the diameter of the trachea; allows the trachea to stretch and remain open while swallowing. if not, you’d choke or suffocate while eating
the carina
most inferior of the tracheal cartilage rings; VERY sensitive cough reflex
which bronchi are you more likely to get something lodged in?
Right, because it is shorter and more vertical
what happens to the bronchi at the inferior part of the trachea, at the level of the carina?
trachea divides into right and left primary (principal) bronchi
what happens to each primary bronchus?
subdivides into 3 right and 2 left secondary or lobar bronchi
what happens to the secondary bronchi?
branch into tertiary or segmental bronchi, bronchioles and terminal bronchioles
how many total orders of branching?
23
structural changes along the bronchial tree
- The walls of the primary bronchi contain rights of cartilage.
- The walls of the bronchioles contain smooth muscle.
- Epithelium changes (Clara cells are simple cuboidal cells that secrete Clara cell lipoprotein); cilia are sparse, and mucus is absent (no dust cells) as passageways become smaller
Clara cell lipoprotein
secreted by Clara cells; prevent bronchial walls from collapsing in
alveolar ducts transition into
alveolar sacs
alveoli
spherical structures located at the terminal ends of the alveolar sacs composed of simple squamous epithelium
alveolar walls consist of
type 1 alveolar cells, type 2 alveolar (septal) cells, alveolar macrophages (dust cells)
type 1 alveolar cells
simple squamous, thin as tissue paper, main site of gas exchange, secrete ace (angiotensin converting enzyme)
alveolar macrophages (dust cells)
engulfs pollen, bacteria, etc.
type II alveolar cells (septal cells) (type II pneumocytes)
secrete alveolar fluid containing surfactant
surfactant
reduces surface tension, prevents collapse of alveoli during expiration
lungs
paired organs in the thoracic cavity; they are enclosed and protected by the pleural (double layered) membrane
parietal pleura
outer layer - lines the pleural cavity; simple squamous
visceral pleura
inner layer - sits on top of lungs (aka pulmonary pleura)
pleural cavity
small potential space between the pleurae, that contains a lubricating fluid (pleural/serous fluid)
pleural effusion
the pleural cavities may fill with air or blood. may cause a partial or complete collapse of the lung; usually from wounds to the chest
pneumothorax
pleural cavities fill with air
hemothorax
pleural cavities fill with blood
pleurisy
occurs when the pleural membranes become inflamed; less fluid produced, tissue becomes dry and rough, breathe=excruciating pain, sounds like two pieces of leather rubbing together (friction rub)
the lungs extend from ____ to _____
diaphragm, superior to the clavicles
each lung contains
a root, a costal (rib) surface, an apex, a base, and a hilus
hilus
indentation in surface of lung; blood vessels and the primary bronchi enter and leave the lungs at the hilus
right lung
3 lobes separated by the horizontal and oblique fissures.
left lung
2 lobes separated by the oblique fissure and a depression (cardiac notch/depression)
what do the tertiary bronchi supply?
segments of lung tissue called bronchopulmonary segments; 10 segments in each lung
bronchopulmonary segment
pyramid or triangle shaped part of lung
what are bronchopulmonary segments subdivided into?
lobules: each lobule contains 5 structures; wrapped in elastic CT
5 structures in a lobule
- lymphatic vessel
- venule (small vein)
- arteriole (small artery)
- terminal bronchiole
- respiratory bronchiole.
how does the blood enter the lungs?
through the pulmonary arteries (pulmonary circulation) and the bronchial arteries. Most of the blood leaves by the pulmonary veins, but some blood drains into the bronchial veins.
pulmonary arteries
come from the heart to the lungs to get oxygenated
pulmonary circulation
blood being brought to the lungs to get oxygenated
bronchial arteries
a branch of descending aorta (thoracic aorta) - feeds blood to lung tissue
where does most blood leave through?
pulmonary veins (oxygenated) - empties into left atrium
what else are the lungs innervated by?
pulmonary plexus of the ANS; mainly parasympathetic (dilating); rarely sympathetic
3 steps of respiration
pulmonary ventilation, external respiration, internal respiration
inspiration
the process of bringing air into the lungs
Boyle’s Law
governs the movement of air into and out of the lungs; pressure of gas varies inversely with its volume, assuming temperature is constant; p1v1=p2v2
quiet inhalation
first step requires the contraction of the diaphragm (mainly) and external intercostals to increase the size of the thoracic cavity
inhalation
occurs when alveolar pressure falls below atmospheric pressure and the thoracic volume increases.
forced inhalation
4 accessory muscles of inspiration are utilized: SCM, scalene muscles, pectoralis minor, external intercostals; all muscles increase the height of the thoracic cavity by lifting the ribcage and pulling sternum forward
exhalation
occurs when the alveolar pressure is higher than the atmospheric pressure and the diaphragm and external intercostal muscles relax; the rib cage lowers and the lungs recoil
why is exhalation a passive process?
it doesn’t rely on pressure changes; it relies on elastic recoil
what does exhalation become active?
during labored breathing and when air movement out of the lungs is impeded (asthma)
forced expiration
employs the contraction of 5 muscles that increase intra-abdominal pressure: latissimus dorsi, internal intercostals, abdominal oblique (internal/external), and transverse abdominis
air flows from ___ to ____
high to low
alveolar surface tension
causes the alveoli to assume the smallest diameter possible; must be overcome
surfactant allows alteration of
allows alteration of the surface tension of the alveoli
compliance
the ease with which the lungs and thoracic wall can be expanded; determined by lowered surface tension of the alveoli and surfactant
high compliance
healthy lungs
low compliance
diminished expansion
resistance
resistance to the normal flow of air into the bronchi and bronchioles; acute asthma increases resistance
asthma
disease of immune system; allergic asthma, smoke induced, exercise induced, frigid air exposure, stress induced
what can dilate the airways?
bronchodilators (albuterol, epinephrine)
what 2 gas laws govern the exchange of oxygen and co2 between the blood and alveoli?
Dalton’s law and henry’s law
Dalton’s law of partial pressures
each gas in a mixture of gases exerts its own pressure independent of other gases; each gas’ pressure is directly proportional to its percentage in the total gas mixture
how is the partial pressure of a gas symbolized?
Px
Nitrogen narcosis and decompression sickness
conditions explained by Henry’s law; Nitrogen is more soluble in lipids than water, it tends to concentrate in the CNS. Rapid ascent decreases the partial pressure of nitrogen abruptly, diffusing it out of the blood stream and trapping it in the interstitial fluid- can cause shocks, seizures, dyspnea, and death
gangrene
severe infection, bacteria are anaerobic, so oxygen kills them
for each 100 ml of oxygenated blood, how is the O2 used?
1.5% is dissolved into the plasma, 98.5% is carried with hemoglobin as oxyhemoglobin
hemoglobin
consists of a protein portion called globin and a pigment called heme, which contains 4 atoms of iron
fully saturated
all 4 heme groups are bound to oxygen
partially saturated
1,2, or 3 heme groups are bound to oxygen
cooperation and affinity
after the first O2 molecule binds to iron, the Hb molecule changes shape to allow it to more readily take on additional O2.
what is the most important factor that determines how much oxygen combines with hemoglobin?
the partial pressure of O2
the greater the PO2, the ____ oxygen will combine with hemoglobin
more
Bohr effect
in an acid (low pH) environment, O2 affinity for Hb is decreased and O2 splits more readily from hemoglobin
what does low blood pH result from?
(acidic) - high PCO2
what happens as temperature increases?
the amount of O2 released from hemoglobin increases
general relationship for O2 affinity with acid and temp?
as you increase acidity and temperature, you decrease the affinity of O2 and less of it binds to Hb
BPG (biphosphoglycerate)
formed in red blood cells during glycolysis and it effects oxygen release from Hb; the greater the level of BPG the lower the affinity of O2 for Hb and more O2 is released from Hb
3 hormones that increase BPG formation
testosterone, thyroxine, HGH —> all enhance O2 delivery to tissues
how is CO2 carried in the blood?
in the form of dissolved CO2 (7%) bound to hemoglobin (carbaminohemoglobin) or converted into bicarbonate ions (70%)
what maintains the ionic balance between plasma and red blood cells?
the conversion of CO2 to bicarbonate ions and the related chloride shift
carbonic anhydrase
contained in RBCs that catalyzes the conversion of CO2 and H2O to carbonic acid H2CO3
respiratory center
in the brain, consists of a medullary rhythmicity area (inspiratory and expiratory areas), pneumotaxic area, and apneustic area
medullary rhythmicity area
the function of the medullary rhythmicity area is to control the basic rhythm of respiration (14-16/min)
pneumotaxic area
upper pons; helps coordinate the transition between inspiration and expiration
apneustic area
sends impulses to the inspiratory area that activate it and prolong inspiration, inhibiting expiration
asthma
characterized by spasms of smooth muscle in the bronchial tubes that result in partial or complete closure of the passageways, inflammation, inflated alveoli, and excess mucus production. common triggers are allergy, emotional upset, aspirin, exercise, and breathing cold air or cigarette smoke
chronic obstructive pulmonary disease (COPD)
respiratory disorder characterized by chronic and recurrent obstruction of air flow, which increases airway resistance; principal types are emphysema and chronic bronchitis
bronchitis
inflammation of the bronchial tubes, the main symptom of which is a productive (raising mucus or sputum) cough
sputum
mucus plus blood
danger of a high salt diet
salt is a bronchoconstrictor and enhances formation of mucus.
