A + P Respiratory System Flashcards
respiratory system main purposes
delivery of O2 to blood
removal of CO2 from blood
maintain acid-base balance in blood
respiratory system parts
passage of air into the lungs
lungs
muscles
passage of air into the lungs
air enters the nostrils and passes through the nasopharynx
and/or
air enters the mouth and passes through the pharynx
air travels through the larynx (voice box)
air passage continued
air travels through the trachea down to the lungs
trachea divides into right and left bronchi, each of which extend into a respective lung
each bronchus divides into smaller bronchioles
each bronchiole contains several alveolar sacs
alveolar sacs
- visual characteristics
- function
visual
-membranous sacs surrounded by pulmonary capillaries
function
-serve as sites for gas exchange (O2 and CO2) with pulmonary circulation
larynx primary structures
epiglottis
glottis
epiglottis
- visual characteristics
- function
visual
-flap of elastic cartilage
function
-guards the entrance of the glottis to prevent food/drink/objects from entering the airway
glottis
a combination of the vocal folds/cords and the space between the folds
lung “tissue” characteristic
- composition
- -composition
fairly elastic
composition
-bronchioles and alveoli
–contain specialized epithelium and smooth muscle
bronchioles
-tissue composition
tissue
-mostly cartilaginous to provide rigidity to the airway
large vs. small bronchioles
large
-lined with ciliated simple columnar cells
small
-lined with simple cuboidal cells
goblet cells and seromucous glands
- location
- function
location
-present in all bronchioles
function
-produce mucous that capture foreign substances
bronchiole epithelium
- surrounded by…
- function of surroundings
surrounded by bands of smooth muscle
constrict to help force air out of the lungs or relax to allow air into the lungs
alveoli tissue
simple squamous epithelial cells
macrophages
- location
- function
location
-within alveoli
function
-engulf, digest, and remove foreign and/or harmful substances
right vs. left lung structure
right lung is separated into three lobes (superior, middle, inferior) by the horizontal and oblique fissures
the left lung is separated into two lobes (superior and inferior) by the oblique fissure
the left lung has a cardiac notch along its medial border to accommodate the heart
how does each lobe receive its air supple
via bronchioles
how are lobes divided
divided into small sections and lobules
pleurae
-divisions
double-walled sac that each lung is enveloped in divisions -visceral pleura -parietal pleura -pleural cavity
visceral pleura
- location
- function
the inner wall
covers lungs
parietal pleura
- location
- function
the outer wall
adheres to the thoracic wall (ribs, diaphragm)
pleural cavity
- location
- function
between each membrane
contains serous fluid (created by each membrane) that helps adhere lungs to thoracic wall
muscles
diaphragm
internal intercostals
external intercostals
diaphragm
- divides…
- contraction…
- relaxation
divides thoracic cavity from abdomen
contraction of diaphragm depresses to bottom wall of the thoracic cavity, thereby expanding the volume of the thoracic cavity for inhalation
relaxation of diaphragm elevates the bottom wall of the thoracic cavity, thereby reducing the volume of the thoracic cavity for exhalation
intercostals
- location
- function
attached to ribs
assist lung ventilation (breathing)
external intercostals
-function
elevate ribs during resting and forced inhalation
internal intercostals
-function
depress ribs during forced exhalation
resting exhalation
passive, elastic process that should not require contraction of the internal intercostals
movement of air depends on
pressure differences between the atmosphere and the spaces inside the lungs
what are the two pressures
intrapleural pressure
intrapulmonary pressure
intrapleural pressure
air pressure within the pleural cavity
intrapulmonary pressure
air pressure within the alveoli
Boyle’s Law
increased volume = decreased pressure
decreased volume = increased volume
Boyle’s Law and ventilation
-2 parts
inspiration
expiration
inspiration
- diaphragm and external intercostals contract, increasing volume of the thoracic cavity
- intrapleural pressure decreases which drops intrapulmonary pressure
- atmospheric air pressure is now higher than intrapleural and intrapulmonary pressures creating a vacuum inside the lung
- atmospheric air is sucked inside, inflating the lungs - O2 supply
expiration
elastic nature of lungs and thoracic cavity, relaxation of diaphragm, and possibly contraction of internal intercostals decrease volume of the thoracic cavity
intrapleural and intrapulmonary pressures increase
atmospheric pressure is now lower than intrapleural and intrapulmonary pressures
air is consequently forced out of lungs
inspired air composition
N2 = 79% O2 = 20.9% CO2 = CO2 = 0.03% H2O = the rest (0.5%)
expired air composition
N2 = 75% O2 = 15% CO2 = 4% H2O = 6%
inspired air partial pressures
PlO2 = 150 mmHg PlCO2 = 0 mmHg
alveolar blood partial pressures
PAO2 = 102 mmHg PACO2 = 40 mmHg
Arterial blood partial pressures
PaO2 = 102 mmHg PaCO2 = 40 mmHg
mixed venous blood partial pressures
PvO2 = 40 mmHg PvCO2 = 46 mmHg
title volume (Vt)
- resting
- aerobic
the volume of air inspired/expired each breath resting -about 0.5 L/breath aerobic exercise -2-4 L/breath
frequency (f)
- resting
- aerobic exercise
the number of breaths taken per minute resting -8-12 bpm aerobic exercise -50-60 bpm
(minute) ventilation (Ve)
- resting
- aerobic exercise
the volume of expired air per minute (Ve = Vt x f) resting -6 L/min aerobic exercise -150-200 L/mind
total lung capacity
-average
the maximum lung volume (not entirely usable, however)
average
-5-6 L
residual volume (RV) -average
the amount of air left in the lungs after a maximum exhalation (i.e. a reserve air supply
average
-1.0 L
forced vital capacity
- also known as
- affected by
the largest volume of air you can possibly expire in a single exhalation (FVC = TLC - RV) also know as Vital Capacity (VC) greatly affected by -gender -age -height -restrictive pulmonary diseases
forced expiration volume in 1, 2, or 3 seconds (FEV1.0, FEV2.0, FEV3.0)
-affected by
the volume of your FVC that can be expired in 1, 2, or 3 seconds greatly affected -gender -age -height -obstructive pulmonary diseases
expiratory reserve volume (ERV)
the maximum expired volume after normal expiration
inspiratory reserve volume (IRV)
the maximum inspired volume after normal inspiration
inspiratory capacity (IC)
the volume between normal expiration and the upper limits of TLC
-many pulmonary diseases affect this
functional reserve capacity(FRC)
the remaining lung volume after normal expiration
gas exchange and transport are…
integrated processes that sustain metabolism
- loading O2 into the blood on Hemoglobin (Hb) at the alveoli
- removing CO2 from the blood at the alveoli
- trasporting O2 to the tissues and unloading it
- loading CO2 from the tissues into the blood and transporting it to the alveoli
factors that affect gas exchange
partial pressure gradients barriers to diffusion diffusion distance molecule size and viscosity of medium RBC transit time ventilation (Va)/Perfusion (Q) ratio
barriers to diffusion
surfactant alveolar epithelium interstitial space capillary basement membrane capillary endothelium
diffusion distance
further O2 has to go, the longer it takes and less will be loaded
molecule size and viscosity of medium
CO2 diffuses 2x faster than O2 because it’s more soluble in H2O, even though O2 is smaller
RBC transit time
within capillary, transit time is 0.75 seconds at rest, down to 0.25 seconds with maximal exercise
ventilation (Va)/perfusion (Q) ratio
represents the relative efficiency of gas exchange from alveoli to blood
-ideal score is 1.0 (unit-less number)
lung blood flow is much greater in lower portion than upper portion, so Va/Q changes depending on the anatomical section of the lung
oxygen transport
O2 diffuses from alveoli into RBC
-within RBC, O2 binds to hemoglobin
95% of O2 is carried by Hb within RBC
-remaining 5% O2 is dissolved in solution (PO2)
–although small, this is important because it is used to monitor ventilation
increases in 2,3-Bisphosphoglycerate (2,3-BPG), H+, CO2, and temperature induce O2 loading in the muscles
O2 unloaded into muscles on Myoglobin (Mb) for use in mitochondrial respiration
carbon dioxide transport
CO2 diffuses from muscle into RBC
5% dissolved in solution (PCO2)
-very important because it is what is monitored for purposes of ventilation
5% carried by Hb
-called carbaminohemoglobin
-remaining CO2 converted to H+ and bicarbonate (HCO3-)
how is CO2 converted
CO2 + H2O –> H+ + HCO3
HCo3 binds to Hb for transport to lungs
H+ “buffered” via binding to proteins in plasma and Hb in RBC
-important because sizeable amounts of CO2 can be transported in blood to lungs without substantially altering pH
at lungs, above reaction is reversed to produce CO2 and H2O, which diffuses into alveoli and is expired
ventilation regulation
- controlled by
- modified by
controlled by
-ventilatory centers (medulla oblongata and pons) in brain (feed-forward system)
modified by
-sensory receptors in periphery (feedback system)
ventilatory centers
-primarily responsible for
primarily responsible for “Anticipatory Rise” in Ve
SNS (Epi and Norepi) elicits bronchodilation to increase airflow into lungs
PSNS elicits bronchoconstriction to decrease airflow into lungs
feedback system
- mechanoreceptors
- chemoreceptors
mechanoreceptors in muscles often dictate rapid rises or sudden drops in Ve due to increase or absence of muscle contraction
chemoreceptors in vessels are responsible for gradual increases, decreases, and plateaus in Ve due to changes in PCO2, pH, lactate, glucose, and catecholamines
what is the primary feedback variable used to dictate Ve
PCO2
homeostatic imbalances
pneumonia cyctic fibrosis asthma/bronchitis emphysema chronic bronchitis
pneumonia
an infection of the alveoli caused by bacteria or viruses tissue fluids (due to the inflammatory response) accumulate in the alveoli, which reduces the surface area exposed to air and ultimately, inhibits the intake of O2 and removal of CO2 from the blood
cystic fibrosis
a defective gene can cause the lungs and pancreas to produce abnormally thick and sticky mucus
this mucus builds up in the bronchi and bronchioles in the lungs and in the pancreas, which provides a fertile breeding ground for pathogenic fungi and bacteria
restrictive lung disease
asthma/bronchitis
an inflammatory constriction of the bronchi and bronchioles that inhibits airflow into and out of the lungs
asthma attacks can be triggered by airborne irritants such as chemical fumes and smoke, airborne allergens, and possibly the turbulence of airflow through the bronchi and bronchioles
emphysema
degredation of the alveolar epithelium, which reduces the surface area of the lungs that can participate in gas exchange
the immediate cause of emphysema seems to be the release of proteolytic enzymes as part of the inflammatory process that follows irritation of the lungs
the condition develops slowly and is seldom a direct cause of death
however, the gradual loss of gas-exchange area forces the heart to pump ever-larger volumes of blood to the lungs in order to satisfy the body’s needs
the added strain can lead to heart failure
chronic bronchitis
any irritant that reaches the bronchi and bronchioles will stimulate an increased secretion of mucus
in chronic bronchitis the air passages become clogged with mucus, which leads to a persistent cough
chronic bronchitis is usually associated with cigarette smoking
vocal cord dysfunction
can be mistaken for asthma
same S/S
combo of asthma, chronic bronchitis, and emphysema
knows as chronic obstructive pulmonary disorders (COPD)
smoking is the #1 cause of COPD
