Respiratory System EXAM III Flashcards
Why is it necessary to move CO2 out of the blood?
because it makes the blood acidic.
What is the purpose of the airways in the body?
to transmit, warm and humidify inspired air.
What are the airways lined with?
ciliated pseudostratified columnar epithelium with goblet cells.
What is the purpose of the cilia in the airways?
help to remove particles.
What is the purpose of the goblet cells in the airways?
to produce mucus that entraps and helps to remove debris.
What are the airways held open with?
bone in the upper airways and cartilage in the lower airways.
What is the path of air through the respiratory system?
a) nasal cavity
b) pharynx
c) larynx
d) trachea
e) Bronchus
f) Bronchioles
g) alveoli
What does the larynx include?
epiglottis, vocal cords, and glottis.
What does the trachea include?
cartilaginous rings, trachealis muscle.
ends in a bifurcation or split.
When is the trachea closed off?
during swallowing.
When is the esophagus closed off?
during breathing.
Why is there a sphincter at the top of the esophogus?
to reduce air flow to the stomach.
Describe the bronchi.
have cartilage, are a continuation of the trachea into the lungs.
Describe the bronchioles.
smooth muscle with no cartilage that are innervated by the autonomic nervous system.
Continuation of the bronchi.
Last place where the gas exchange does not occur.
What are the alveoli?
sac-like structures where gas exchange occurs. the functional portion of the lung.
What are the pores of Kohn?
pores that keep the alveoli from collapsing.
Describe the type I alveolar cells/pneumocytes.
made up of simple squamous epithelium.
used for gas exchange.
very thin.
Describe the type II alveolar cells/pneumocytes.
produce surfactant–a phospholipoprotein that reduces surface tension, keeps . the alveoli from collapsing, breaks H2O association.
What are alveolar macrophages?
found in the lumen of the alveolus and can wander.
perform nonspecific immunity.
Describe the diaphragm.
the primary muscle for inspiration. The phrenic nerves (C3-C5) stimulate the diaphragm.
What are the external intercostal muscles?
located between the ribs. Elevate the ribs upward and outward to expand.
What are the scalenus and sternocleidomastoid?
raise the sternum and elevate the ribs. Only used in strenuous breathing.
Describe the function of the abdominal muscles.
increase abdominal pressure and pressure on the thorax by pushing the abdomen.
What are the internal intercostal muscles?
pulls the ribs down and in, decreasing the volume of the thoracic cavity. Used only in active expiration.
What is the atmospheric pressure at sea level?
760 mmHg
How does the atmospheric pressure change as the altitude increases?
the pressure decreases.
What is the intrapulmonary pressure (intra-alveolar pressure)?
pressure within the alveoli. Equal to the atmospheric pressure. 760 mmHg
What is the intrathoracic pressure (intrapleural pressure)?
pressure within the thoracic cavity. Located between the lungs and teh chest wall.
usually around 756 mmHg.
What is the transmural pressure gradient?
the difference between the alveolar and pleural pressure.
What is the gist of Boyle’s law?
volume and pressure are inversely related.
Describe intrapleural fluid cohesiveness.
keeps teh thoracic walls and lungs in close proximity and lubricates.
What is ventilation an example of?
bulk flow of gases.
What conditions must be met for air to flow into the lungs?
the pressure at the alveolar level must be less than the atmospheric pressure.
What conditions must be met for air to flow out of the lungs?
the alveolar pressure must be greater than atmospheric pressure.
What do the muscles of respiration alter?
the volume of the thoracic cavity, which in turn alters the volume of the lungs.
What kind of process is inspiration?
an active process, meaning that the activity of muscles is required.
What happens when the thoracic cavity expands?
the volume in the interpleural space increases, decreasing the pressure to 754 mmHg, which also decreses the intra-alveolar pressure to 759 mmHg, so air flows down the pressure gradient.
Inspiration.
What kind of process is expiration?
a passive process, in the resting state.
What does expiration rely on?
the elastic fibers in the lungs for recoil. The alveolar pressure is 761 mmHg, which is greater than atmospheric pressure, 760 mmHg.
What is the pressure difference at the end of inhalation?
the alveolar pressure is equal to the atmospheric pressure.
What does a decrease in radius do to the air flow?
it diminishes the flow.
Describe asthma.
a smooth muscle problem in which the resistance to flow increases.
Describe bronchitis.
inflammation of the lining of the bronchi, in which the resistance to flow increases.
Describe emphysema
the collapse of smaller airways.
breakdown of alveolar walls leading to larger alveoli, but fewer alveoli. (less total surface area).
What happens to the arterioles when the bronchioles dilate?
they also dilate.
What does CO2 control?
the dilation of bronchioles. As blood flow increases, CO2 in the alveoli increases, which leads to increased dilation of bronchioles to improve airflow.
What is compliance?
how stretchy or willing to expand the lung is. Helps to determine recoil.
the more elastic the tissue, the more likely the alveoli will collapse.
What influences compliance?
the alveolar surface tension.
What does surface tension of water normally do?
would cause the alveoli to collapse.
How does the alveolar surface tension affect compliance?
it opposes expansion.
What does surfactin do?
helps to prevent the collapsing of alveoli.
Breaks water interactions and surface tension.
What is surfactant produced by?
type II alveolar pneumocytes.
When are type II alveolar pneumocytes produced?
at 8 months of gestation.
What is the law of laplace?
P=2T/r, where P=inward collapsing pressure, T=surface tension, r=radius of alveoli.
What does the law of laplace state?
the tendency to collapse is directly related to the surface tension and inversely related to the radius of the alveolus. **Surfactant reduces tension.
What does it mean that alveoli are interdependent?
if one starts to collapse, the other help to hold it open by equalizing the pressures.
What happens if babies are born before 8 months of gestation?
they suffer newborn respiratory distress syndrome.
How much of the body’s energy is used for resting breathing?
3%
What happens when there is a decrease in pulmonary compliance?
there is an increase in the work required.
up to 30% of energy consumption.
What happens if there is an inrease in airway resistance?
there is an increase in the work required.
Up to 30%
What happens if there is a decrease in elastic recoil?
there is an increase in the work required
Up to 30% of energy consumption.
involved in exhale.
Describe the increased need of energy with exercise.
increase in work required.
up to 30% of energy consumption.
energy needed for breathing larger volumes of air at a faster rate.
What is the normal volume of air in the lungs?
2 to 2.5 liters
What is the maximum capacity of air in the lungs?
males: 5.7 Liters.
Females: 4.2 liters.
What is the tidal volume?
the volume of air entering or leaving the lungs during a single breath.
Under resting conditions: 500mL.
What does an obstruction to air flow cause?
a reduction in the maximum air flow.
What is the inspiratory reserve volume (IRV)?
the extra air that can be inspired after a normal quiet inspiration
3000mL
What is the inspiratory capacity (IC)?
the maximum volume of air that can be inhaled after a normal quiet expiration.
IC=TV+IRV=3500mL
What is the expiratory reserve volume (ERV)?
the maximum volume of air that can be breathed out after a normal quiet exhalation.
1000mL
What is the residual volume (RV)?
the volume of air remaining after maximal expiration.
1200 mL
What is the functional residual capacity (FRC)?
the volume of the air remaining in the lungs after a passive expiration. FRC=ERV+RV
22mL
What is the vital capacity (VC)?
the volume of air that can be moved out of the lungs following maximal inspiration
VC=IRV+TV+ERV
4500 mL
What is the total lung capacity (TLC)?
the maximum volume of the lungs
TLC=VC+RV
5700mL
What is teh forced expiratory volume in one second (FEV1)?
the volume of air that is exhaled in the first second when determining VC. Measure maximal airflow rate that is possible from the lungs.
80% of VC.
needed to determine is there is obstructive lung disease or restrictive lung disease.
What is the pulmonary (minute) ventilation?
the amount of air breathed in or out in one minute.
TV*Respiratory Rate.
What is the pulmonary ventilation in an average resting adult?
500mL/breath*12 breaths/min= 6000ml/min
What is the alveolar ventilation?
the amount of air actually available for gas exchange per minute.
What is the anatomical dead space?
the volume of respiratory tract that does not participate in gas exchange.
150 mL
What is the equation for the volume of the lung that actually participates in gas exchange?
tv-dead space.
500-150=300mL of fresh air moves into the alveoli with each quiet breath.
What is the equation for alveolar ventilation?
(TV-dead space)*RR
350mL*12 breaths/min=4200 mL/min
What are partial pressures?
based upon the percentages of gas in air and atmospheric pressures.
What is the partial pressure of nitrogen?
600mmHg
What is the partial pressure of oxygen?
160mmHg
What is the partial pressure of carbon dioxidee?
0.23mmHg.
What is the amount of gas dissolved in blood dependent on?
the solubility of gas in blood.
the partial pressure of the gas in the liquid portion of blood.
What is the partial pressure of water?
47mmHg
What does saturation of air with water reduce the partial pressure of nitrogen to?
562mmHg.
What does the saturation of air with water reduce the partial pressure of oxygen to?
150mmHg.
What does the mixing of inhaled air with stale air in the alveoli lower the partial pressure of oxygen to?
100mmHg.
What is the partial pressure of oxygen in the pulmonary arteries prior to gas exchange?
40mmHg
What is normal alveolar partial pressure of carbon dioxide?
40mmHg
What is the normal capillary partial pressure of carbon dioxide?
46mmHg
What happens after oxygen diffuses in the blood down the partial pressure gradient?
100mmHg in the alveoli causes the partial pressure of oxygen in the blood to increase from 40 mmHg to 100 mmHg
What happens after carbon dioxide diffuses into the alveoli?
the partial pressure of carbon dioxide falls from 46mmHg in the blood entering the pulmonary capillaries to 40mmHg partial pressure in the blood leaving the capillaries of the lungs.
What happens if more oxygen is utilized, during exercise for example?
partial pressure of oxygen in the blood decreases even further, increasing the partial pressure gradient, and increasing the exchange of oxygen in the pulmonary capillaries. Similarly, more carbon dioxide is transported from the blood into the alveoli.
Describe the change of surface area during exercise.
during exercise, blood flow increases and additional alveoli are utilized and alveoli expand, increasing the total surface area for gas exchange.
Describe the solubilities of carbon dioxide and oxygen.
carbon dioxide is 20 times more sluble than oxygen and diffuses far more rapidly than oxygen.
What diseases can cause increased membrane thickness?
pneumonia
pulmonary edema
pulmonary fibrosis.
What diseases can cause a reduction in surface area?
emphysema pulmonary atelectases (collapsed regions).
Describe oxygen in gas transport.
dissolved in plasma.
poorly soluble, 1.5% of oxygen in the blood is dissolved.
only about 3 ml of oxygen in 1 liter of blood.
the resting body needs 250mL/min and 25X more whe exercising.
What is the amount of oxygen bound to hemoglobin determined by?
the partial pressure of oxygen.
How much of the oxygen in blood is bound to hemoglobin?
98.5%
What is reduced hemoglobin?
hemoglobin that is not combined with oxygen.
What is oxyhemoglobin?
hemoglobin that is combined with oxygen.
Where does oxygen bind to hemoglobin?
to the iron containing portion (heme group).
What is hemoglobin saturation?
the percentage of hemoglobin in the blood that is oxyhemoglobin.
What is the hemoglobin saturation determined by?
the PO2 law of mass action:
Hb+O2–>HbO2.
What is an O2-Hb dissociation (saturation) curve?
plots the relationship between PO2 and %Hb saturation.
What is the saturation at PO2 of 100mmHg?
97.5%
What is the saturation at PO2 of 60mmHg?
90%–Plateau phase.
Where is the curve the steepest and what does this allow for?
between 20 and 60mmHg.
allows for release of oxygen to the tissues.
What does hemoglobin store?
oxygen to be diffused into the tissues.
What happens as blood PO2 falls?
more oxygen is released from hemoglobin and diffuses into the tissues.
What happens when PCO2 increases?
the pH increases.
What is the affinity of O2 for hemoglobin influenced by?
temperature amount of CO2 present Hydrogen ion concentraion The Bohr effect 2,3-bisphosphoglycerate Carbon monoxide
how does temperature affect the affinity of O2 for hemoglobin?
as temperature increases, the curve shifts to the right, so that Hb saturation decreases. As temperature decreases, the curve shifts to the left, so that Hb saturation increases.
How does the amount of carbon dioxide present affect the affinity of O2 for Hb?
increases in PCO2 shift the curve to the right, so that Hb saturation decreases, making it easier to unload oxygen.
How does hydrogen ion concentration affect the affinity of O2 for Hb?
as the blood becomes more acidic, the affinity decreases, shifting the curve to the right.
How does the Bohr effect affect the affinity of O2 for Hb?
bohr effect: Co2 and acidity shift the curve to the right.
at the tissue level, metabolic wastes are high, causing a shift to the right, releasing more oxygen into the tissues.
How does 2,3-bisphosphoglycerate (BPG) affect the affinity of oxygen for Hb?
BPG is a metabolite of RBC’s that can bind to Hb and reduce affinity for oxygen (shifts to the right).
What happens as Hb is chronically undersaturated?
BPG production increases.
How does carbon monoxide affect the affinity of oxygen for Hb?
CO binds 240X more readily to Hb than O2 does to form HbCO. This makes Hb unavailable for binding to O2 and shifts the curve to the left, which diminishes release of oxygen to the tissues.
Describe fetal hemoglobin.
has a much stronger affinity for oxygen in order to move more oxygen to the baby in the blood.
How much Co2 is transported as bicarbonate?
60%.
How is the transport of CO2 as bicarbonate accomplished?
by carbonic anhydrase enzymes present within the RBCs
Which is more soluble: HCO3- or CO2?
HCO3-
What is the chloride shift?
The RBC membrane has a HCO3- Cl- carrier that exchanges HCO2- for Cl- to maintain the electrochemical balance across the membrane.
What percentage of CO2 combines with hemoglobin?
30%.
forms carbamino hemoglobin (HbCO2).
Where does CO2 bind to the hemoglobin?
on the globin portion.
What is the haldane effect?
reduced Hb has a higher affinity for CO@ than HbO2, so once oxygen has been released, CO2 is more readily taken up.
Where does the remaining 10% of carbon dioxide go?
dissolved in the plasma membrane.
this is the portion that physically crosses the membranes.
What is the most important buffer in the body?
HCO3-
What is hypoxia?
insufficient oxygen at the cellular level.
What is hypoxic hypoxia?
decreased oxygen from respiratory sources.
high altitude.
What is anemic hypoxia?
too little oxygenated blood, low Hb levels, or CO poisoning, which reduced oxygen carrying capacity.
What is circulatory hypoxia?
circulatory failure.
What is histotoxic hypoxia?
the inability of cells to utilize the oxygen. KCN poisoning.
What is hyperoxia?
increased oxygen.
What is hypercapnia?
increased CO2 by hypoventilation.
results in a build up of carbonic acid and a respiratory acidosis
What is hypocapnia?
decreased CO2.
true hyperventilation–blows off too much CO2.
results in respiratory alkalosis.
How are rhythmic breathing patterns always controlled?
extrinsically
Describe the function of the medullary respiratory center.
area of pacemaker for regular breathing patterns and control of breathing during increased demand.
What is the Dorsal respiratory group?
located in the medullary respiratory center.
contains inspiratory neurons.
Believed to act as a pacemaker for inspiration.
stimuli from these neurons initiates inspiration.
lack of stimuli initiates passive expiration.
What is the Ventral respiratory group?
located in the medullary respiratory center.
interconnects with the DRG and contains both inspiratory and expiratory neurons. This center remains inactive during quiet breathing, but is activated during times of increased demand.
What do respiratory centers in the pons control?
fine tuning of respiratory pattern.
What is the pneumotaxic center?
respiratory center located in the pons.
limits the duration of inspiration by inhibiting the DRG.
What is the apneustic center?
respiratory center located in the pons.
Prevents inhibition of DRG.
How do the pneumotaxic center and apneustic center work together?
balance each other out to maintain even respiratory patterns.
What is the phrenic nerve?
the major motor neuron of respiration.
exits spinal column higher than expected.
comes from C3-C5
How is arterial PO2 regulated?
medullary respiratory center receives input from carotid bodies and aortic arch bodies that sense changes in PO2.
these are relatively insensitive, because the arterial PO2 must fall below 60mmHg before respiration is reflexively increased.
does not play a role in normal everyday respiration.
How is arterial PCO2 regulated?
the respiratory control center is very sensitive to changes.
What does an increase in PCO2 stimulate?
the medullary respiratory centers and increases breathing.
What does a fall in PCO2 stimulate?
inhibition of the respiratory centers and breathing diminishes.
Where are receptors for CO2 located?
the brain stem.
respond to changes in hydrogen concentration that are induced in the CSF by changes in CO2.
What happens when there is an increased need for oxygen?
PO2 does not decrease, but may slightly increase due to increased perfusion and gas exchange.
PCO2 does decrease, although more CO2 is being produced. it is rapidly removed from the blood by increased ventilation.
Hydrogen does not increase in moderate exercise as CO2 is readily removed. In heavy exercise, hydrogen ions increase due to both lactic acid and increased CO2.
What cause indirect increases in ventilation.
body movements.
increased body temperature
epinephrine release
cortical stimulation
What is apnea?
transient cessation of breathing.
Describe sleep apnea.
the DRG is less sensitive to PCO2 and apnea commonly occurs during this time. can last for a few seconds or minuts and occurs 500X a night.
What is respiratory arrest?
cessation of breating.
What is SIDS
sudden infant death syndrome.
a form of sleep apnea that can lead to respiratory arrest.
What is dyspnea?
shortness of breath. sometimes psychological.
