Exam 2- Chapter 22 Flashcards
-body tissues supplied with oxygen, and CO2 waste must be disposed of
-most important function of the respiratory system
gas exchange
four processes involved with gas exchange
pulmonary ventilation, external respiration, transport of respiratory gases to/from tissues, internal respiration
pulmonary ventilation
breathing, bringing air into and out of the lungs
gas exchange occurring in the lungs; oxygen brought in, carbon dioxide removed
external respiration
function of the cardiovascular system, not respiratory system
transport of respiratory gases to/from tissues
gas exchange occurring in the tissues; removing oxygen from the blood to enter body tissues and pushing carbon dioxide into the lungs to be removed- not part of the respiratory system
internal respiration
two zones of the respiratory system
conducting zone, respiratory zone
-respiratory passages leading from nose to the respiratory bronchioles
-transports air to and from the lungs
conducting zone
-actual site of gas exchange
-found in respiratory bronchioles, alveolar ducts, and alveoli
respiratory zone
major site of gas exchange
alveoli
makes up the upper conducting zone
nasal cavity and pharynx (nasopharynx, oropharynx, laryngopharynx)
air is warmed and humidified as it passes through this cavity before it gets to the lungs
nasal cavity
composed of goblet cells and seromucous nasal glands
respiratory mucosa in the mucous membranes of the nasal cavity
mucous-producing cells
goblet cells
-mucous portion traps particles and debris
-serous portion secretes watery fluid containing lysozyme- destroy pathogens stuck by mucous
-become overactive when you have a cold –> why you get stuffy
seromucous nasal glands
invading debris triggers a sneezing reflex to force it out
purpose of nerve endings in mucous membrane of nasal cavity
vascularization of mucous membranes of nasal cavity
capillaries and veins are located superficially to help warm air as it passes through
cause of nosebleeds
capillaries and veins sitting just under the mucous membrane of nasal cavity close to blood source
three regions of the pharynx
nasopharynx, oropharynx, laryngopharynx
-contains pharyngeal tonsil and tubal tonsil
-closes during swallowing by soft palate and uvula
nasopharynx
-meets oral cavity at isthmus of the fauces
-contains palatine tonsils and lingual tonsils
oropharynx
where nasal passages and oral cavity first meet
isthmus of the fauces
where respiratory and digestive passages split
laryngopharynx
divides the laryngopharynx from the respiratory passages; prevents food and fluid from entering the respiratory system
lower conducting zone
three parts of the lower conducting zone
larynx, trachea, bronchi
cartilage flap that closes off the lower conducting zone; prevents things from “going down the wrong pipe”
epiglottis
-voice box
-composed of cartilage –> thyroid and circoid cartilage
-contains vocal cords
larynx
controls size and thickness of thyroid cartilage
hormones- testosterone causes it to become larger and thicker –> adam’s apple
sound production in larynx
-contains the glottis
-ligaments composed of elastic fibers that vibrate as we exhale to produce sound
vocal cords
open passageway surrounded by vocal cords
glottis
higher pitch/frequency
vocal cords are tight, vibrate faster
hormonal control of voice pitch/frequency
testosterone causes deeper pitch/lower frequency voice
increases loudness of voice
air passing across vocal cords with greater force –> higher amplitude
-composed of elastic fibers and cartilage rings
trachea (windpipe)
provide flexibility to trachea so it can stretch and relax while breathing
elastic fibers
importance of cartilage rings in trachea
-allow trachea to remain open all the time- important for breathing/ventilation
-prevents trachea from collapsing on itself after each exhale
smooth muscle tissue of trachea
trachealis
when the trachealis contracts
-diameter of trachea decreases
-trachea becomes more narrow
-forces air up and out of the body –> coughing reflexes
allow air to reach the respiratory zone
the bronchi
the trachea branches to form how many bronchi
2 main bronchi
bronchioles
bronchi branch about 20-25 times
terminal bronchioles
smallest of the bronchioles in conducting zone- actual exchange into lung tissue
organ where external gas exchange occurs
lungs
hilum
each lung has this- point at which the bronchi and any blood/nerve supply enter/leave the lung
composition of lungs
air space and elastic connective tissue
pulmonary artery brings oxygen-poor blood to lungs
- artery branches in a similar pattern as bronchi
pulmonary circulation
immediately surrounds alveoli
-where gas exchange actually occurs
pulmonary capillary network
moves oxygenated blood away from the lungs and back to the heart
pulmonary vein
bronchial arteries supply lung tissue with oxygenated systemic blood
-lung tissue cells get everything they need–> gas exchange, nutrients, etc.
bronchial circulation
nerve fibers enter the lungs here (at the hilum and bronchi)
pulmonary plexus
causes the air tubes in the lungs to dilate/become wider
sympathetic fibers of the lungs
causes the air tubes in lungs to constrict- become more narrow
parasympathetic fibers in lungs
covers thoracic wall and upper portion of diaphragm
parietal pleura
thin, double-layered serous membrane
pleurae
covers external lung features
visceral pleura
pleural fluid
fills cavity between visceral and parietal layers
creates chambers for each lung
each lung has its own pleura
benefits of each lung having its own pleura
-as organs move/shift with breathing –> pleural layers “slide over” one another- prevents abrasion
-prevents spread of infection from one organ to another
-first true structure of respiratory zone
-branch from the terminal bronchioles of the conducting zone
-lead into alveolar sacs composed of multiple alveoli
respiratory bronchioles
make up the walls of the alveoli
simple squamous epithelia- single layer of flattened cells helps for quick and efficient gas exhcnage
cover alveoli
capillary beds where gas exchange happens via diffusion down concentration gradient
connect neighboring individual alveoli
alveolar pores
three cell types of alveoli
type 1 alveolar cells, type 2 alveolar cells, alveolar macrophage
squamous epithelial cells
-function- create walls of alveoli –> where gas exchange occurs
type 1 alveolar cells
cuboidal cells scattered among type1 cells
function- secrete surfactant and antimicrobial proteins
type 2 alveolar cells
surfactant
slippery detergent-like substance
-prevents walls of alveoli from sticking together each time you exhale
innate immunity in alveoli
antimicrobial proteins
mobile cells
function- consume debris, pathogens, etc. –> protect internal alveolar surfaces
alveolar macrophage
2 processes involved with respiratory physiology
pulmonary ventilation, gas exchange
the flow of air into and out of the lungs
- air flows according to a pressure gradient (high to low)
pulmonary ventilation
the exchange of respiratory gases across the alveolar wall (external gas exchange- perfusion)
gas exchange
3 gas laws that influence respiratory physiology
Boyle’s law, Dalton’s law of partial pressures, Henry’s law
Boyle’s Law
the volume of a gas is inversely proportional to the pressure exerted by the gas on the walls of its container
atmospheric pressure at sea level
760 mmHg
pressure in the lungs is described relative to __ __
atmospheric pressure
pressure in the alveoli, changes as you inhale or exhale
-always equalizes Patm at some point
intrapulmonary pressure (Ppul)
initiated by contraction of inspiratory muscles- change in volume of thoracic cavity
inspiration
flattens during contraction and pulls down, accommodates for the increase in lung volume during inhalation
-skeletal muscle tissue
diaphragm
pull ribs up and outward during contraction
-skeletal muscle tissue
-thoracic cavity becomes larger
intercostal muscles
intrapulmonary pressure when the lungs increase in size
intrapulmonary pressure decreases relative to atmospheric pressure
when inspiration ends because there is no longer a gradient
Ppul = Patm
-mostly due to lung elasticity
-respiratory muscles relax and return to resting length
-elastic fibers of lungs recoil and lungs become smaller in size
expiration
the amount of air that can be pushed into/out of lungs during ventilation
respiratory volumes
normal volume of air that moves into and out of lungs during normal breathing
-in healthy individuals ~500 ml air
tidal volume (TV)
amount of air that can be inspired forcibly past the tidal volume
-until you can’t get anymore air in
-~2100-3000 ml air
inspiratory reserve volume (IRV)
amount of air that can be forcibly exhaled past the tidal volume
-until you can’t expire anymore
-~1000-1200 ml air
**not equal to the IRV because even when you breath out all the way there is still air left over
expiratory reserve volume (ERV)
amount of air left in the lungs after forced expiration
~1200 ml air
residual (reserve) volume (RV)
the sum of two or more respiratory volumes
-better medical indication of respiratory capabilities
respiratory capacities
total amount of air that can be inspired after a normal tidal volume expiration
= TV + IRV
-indicates inability to bring air into the lungs
inspiratory capacity (IC)
amount of air remaining in the lungs after a normal tidal volume expiration
= RV + ERV
higher value means you can’t expel as much air from the lungs
functional residual capacity (FRC)
total amount of exchangeable air
= TV + IRV + ERV
vital capacity (VC)
sits in lungs- is not exchangeable
why residual volume does not contribute to vital capacity
the total amount of air the lungs can hold after a maximum inhalation
= IRV + TV + ERV + RV
healthy ~6 liters of air
total lung capacity (TLC)
air that fills the conducting zone, but never contributes to gas exchange
dead space
~150 ml air for a healthy individual
-1 ml air per pound of ideal body weight
anatomical dead space
total volume of air used for gas exchange
~350 ml
dead space in the respiratory zone
-air reaches the alveoli, but no gas exchange occurs due to damage or collapse of alveoli (respiratory diseases)
alveolar dead space
anatomical dead space + alveolar dead space
“non-useful volumes”
total dead space
the total pressure exerted by a mixture of gases is the sum of the pressures exerted independently by each gas in the mixture
Dalton’s law of partial pressures
account for 99% of Patm
nitrogen (79%, 597 mmHg) and oxygen (20.9%, 159 mmHg)
the pressure of each individual gas in a mixture
partial pressure (PP)
partial pressure of oxygen in alveoli
13.7% = 104 mmHg
partial pressure of CO2 in alveoli
5.25% = 40 mmHg
importance of knowing partial pressures of gases
see the pressure gradients that drive diffusion into or out of the blood
a gas will dissolve in a liquid in proportion to its partial pressure
Henry’s Law
higher partial pressure (henry’s law)
more gas dissolves in liquid
best conditions for gas to dissolve
high pressure, low temperature, high solubility
ex- carbonated drink
partial pressure of oxygen (henry’s law)
higher in the alveoli (gas) compared to the blood (liquid)
-first factor affecting rate/efficiency of gas exchange between alveoli and capillaries
-Po2 in alveoli > Po2 in lung capillaries –> oxygen moves from alveoli into blood
partial pressure gradients and gas solubility
why equal amounts of CO2 and O2 are exchanged between alveoli and blood
carbon dioxide is more soluble but oxygen is a smaller gas molecule and moves more quickly
2nd factor affecting rate/efficiency of gas exchange between alveoli and capillaries
-respiratory membrane is very thin –> gas exchange occurs quickly
thickness and surface area of respiratory membrane
greater surface area
greater amount of gas that can diffuse in a given amount of time
alveolar surface area (HUGE)
~70m^2 = ~750 sq. ft.
3rd factor affecting rate/efficiency of gas exchange between alveoli and capillaries
-optimal gas exchange results from equal amounts of gas reaching alveoli (via ventilation) and blood supply to pulmonary capillaries (via perfusion)
ventilation-perfusion coupling
flow of blood through blood vessels
perfusion
influence of Po2 on perfusion (occurring at the lungs)
low local Po2 –> local arterioles of those alveoli constrict
high local Po2 –> local arterioles of those alveoli dilate
why low local Po2 makes arterioles constrict
blood is redirected to respiratory areas with high Po2 to ensure adequate O2 uptake
why high Po2 makes arterioles dilate
area is flooded with blood –> takes up maximum amount of O2
influence of Pco2 on ventilation
high local Pco2 –> bronchioles dilate
low local Pco2 –> bronchioles constrict
why bronchioles dilate with high local Pco2 levels
CO2 is eliminated by the body faster
-important because increased CO2 affects blood pH
alveolar gases are mostly made up of __ and __ __
CO2 and water vapors (composition)
atmospheric gases are mostly made up of __ and __
nitrogen and oxygen (composition)
why the composition of atmospheric and alveolar air are different
1- gas exchange occurring in alveoli
2- conducting passages humidify air
3- mixture of air in alveoli (reserve volume)
diffusion of CO2 and O2 happen in __ directions
opposite directions
transports oxygen (4 O2 per molecule)
hemoglobin
arterial blood is __% saturated
98%
venous blood is __% saturated
75%
venous oxygen reserve
body tissue cells never use all the oxygen in arterial blood
-this allows us to have small changes in respiratory rate and HR without affecting body cells too much
three ways carbon dioxide is transported
1- dissolved in plasma
2- bound to Hb
3- as bicarbonate ions in plasma
how carbon binds to Hb
amino acids of globulin
most influential/frequently used system to transport CO2
as bicarbonate ions (HCO3-) in plasma
formation of bicarbonate ions
-CO2 diffuses into erythrocyte and combines with H2O to form carbonic acid (H2CO3)
-carbonic acid leaves erythrocytes and split to form H+ and HCO3- (bicarbonate)
causes the release of H+
-normally buffered by red blood cells which maintain the 7.35-7.45 pH of blood
conversion of CO2 to bicarbonate
causes the blood pH to decrease
increase in CO2 in the blood
respiratory acidosis
caused by slow, shallow breathing
causes blood pH to increase
decrease in CO2 in the blood
respiratory alkalosis
caused by rapid, deep breathing (hyperventilation)
two areas that set the normal respiratory rhythm- determines rate and depth of breathing
-central nervous system control
Medullary respiratory center
ventral respiratory group (VRG)
-concerned with changing the size of the thoracic cavity
-some neurons in this group fire during inspiration, others fire during expiration but they cannot fire at the same time
-modifies rhythm set by VRG
-integrates information from other structures and delivers it to VRG
-communication center
dorsal respiratory group (DRG)
interacts with medullary respiratory centers to “smooth” the respiratory pattern
-balances out transitions from inspiration to expiration
Pontine respiratory center (PRC)
most potent and closely controlled factor measured by the CNS to determine breathing rate and depth
CO2
an increase in Pco2 levels in blood
-decreases blood pH (respiratory acidosis)
hypercapnia
a decrease in Pco2 levels in blood
-causes blood pH to increase (alkalosis)
hypocapnia
stimulates increased ventilation
Po2 of arterial blood drops substantially
strong emotion and pain send information from the hypothalamus and limbic system to respiratory centers
hypothalamic control
excitation __ respiratory control
stimulates respiratory control
we can override the respiratory centers to control our own breathing depth/rate- the conscious brain
-this only goes so far –> you cannot hold your breath forever
cortical controls
adjustment to normal respiration during exercise
active muscles need large amounts of oxygen and produce large amounts of waste
-increase respiratory rate and depth
ventilation increases 10-20x during exercise
hyperpnea
group of conditions characterized by a physiological inability to expel air from the lungs
-is irreversible
chronic obstructive pulmonary disease (COPD)
permanent enlargement of the alveoli and eventual destruction of their walls
-lungs lose elasticity
emphysema
barrel chest
hyperinflation of alveoli
chronic production of excess mucous due to inhaled irritants
-lower respiratory passages become inflamed over time and eventually fibrose
chronic bronchitis
mucous not removed from lungs
bacteria and microorganisms thrive in stagnant mucous
cause of frequent infection in chronic bronchitis
-similar to COPD
-temporary bronchospasm attacks followed by symptom-free periods
asthma
most common form of asthma
-allergen causes inflammation of airways
allergic asthma
causes inflammation in allergic asthma
IgE antibodies (histamine)
treatment for asthma
inhaled corticosteroids (decrease inflammation) and or/ bronchodilators
bacterial disease spread (primarily) by inhaled air
-mostly affects lungs but can spread to other organs too
-immune response contains bacteria to hardened nodules in lungs –> bacteria cannot cause infection
tuberculosis
symptoms of active tuberculosis
fever, night sweats, weight loss, racking cough, coughing up blood
characterized by temporary cessation of breathing during sleep
-results in constant fatigue –> leads to increased susceptibility to hypertension, heart disease, stroke, etc.
sleep apnea
common forms of sleep apnea
obstructive sleep apnea
central sleep apnea
occurs when upper airways collapse during sleep
-pharynx muscles relax during sleep –> airway sags and closes
obstructive sleep apnea
respiratory centers of the brain “slack” during sleep –> breathing rhythm/rate not maintained
central sleep apnea
