EXAM 3: SEC2/Breathing Flashcards Preview

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Flashcards in EXAM 3: SEC2/Breathing Deck (32):

Resp system functions

- bring atmospheric air into body and provide opportunity for diffusion of O2 and CO2 across resp. membrane
- blood carries O2 to tissues and CO2 away from


Specialized Functions of Resp

- controlled ventilatory movements with fine control of oval muscles allow for taling
- mucociliary lining of conduction system helps prevent harmful matter into body and infectious organism
- endothelial lining activates/deactivates certain chemical messengers
- pulmonary capillary bed traps emboli from legs or other regions may prevent clots from reaching brain and heart
- diaphragm is primary muscle for quiet breathing


Airway in order

- trachea
- bronchi
- bronchioles
- terminal bronchiolea
- resp bronchioles
- alveolar ducts
- alveolar sacs



- pulmonary artery and branches = deoxygenated
- pulm arteries = deoxygenated
- pulm veins = oxygenated
- systemic arteries = oxygenated
- systemic veins = deoxygenated



- pleura membrane protects
- intrapleura fluid inbetween
- lungs not symmetrical
- left lung = 2 lobes
- right lung = 3 lobes



- purpose = bring ambient air into close contact with pulonary capillary blood to exchange O2/CO2
- flow through tubule structures is directly proportional to the pressure difference to the ends of the tubes and inversely proportional to the resistance of flow from radi and length of tubes
- when atmo pressure is greater than alveolar pressure, air flows into lungs
- intrapleural pressure always = 3mmHg less than atmospheric pressure


Ventilation Equation

(Alveolar pressure - atmospheric pressure) / resistance to airflow
= force promoting air flow
- 1 mmHg is all needed to move normal breath


Events of Inspiration

- diaphragm and inspiratory inercoastals contract
- thorax expands
- interpulmonary pressure becomes more subatmospheric
- increase transpulmonary pressure
- lungs expand
- alveolar pressure becomes subatmospheric
- air flows into alveoli


Lung Compliance

- measure of stiffness of the lung
- compliance is the difference in lung volume/ transpulmonary pressure difference
- as trasnpulmonary pressure increases, lung pressure increases
- increase compliance = lung is less stiff = easier to inflate
- if decrease compliance, takes greater change in pressure



- measures breathing
- nose clip
- breath normal, then big in and big out
- tidal volume = 500 ml in average person at rest
- dead space = air that does not participate in gas exchange


Gas exchange and transport

- O2 moves from alveolar gas to capillary down concentration gradient
- CO2 moves from capillary blood into alveolar gas down its concentration gradient
- gas exchange ratio 200/250 = 0.8


Partial Pressures of Gas

- diffuse capacity of the lung for CO2 is higher than for O2, so smaller partial pressure is enough


Gas Exchange

- as blood passes along pulmonary capillary, PO2 rises until is same as alveolar PO2
- rises pretty rapidly
- usually reaches alveolar PO2 1/4 way through capillary
- systemic venous PO2 is starting point because it is what is ended within systemic circulation and therefore what it starts with in the pulmonary system
- blood flow and ventilation needs to match to keep correct amounts of air/O2 in the body to avoid too much CO2
- O2 is transported via blood bound to hemoglobin
- O2 atoms bind reversibly to iron


Venous pressures

- PO2 = 40 mmHg
- PCO2 = 46 mmHg


Arterial pressures

- PO2 = 100 mmHg
- PCO2 = 40 mmHg


Alvoli pressures

- PO2 = 105 mmHg
- PCO2 = 40 mmHg


Atmospheric pressures

- PO2 = 160 mmHg
- PCO2 = 0.3 mmHg


Transport of O2

- hemoglobin has 4 groups --> 2 alpha/2beta
- normal hemoglobin molecule can bind 4 molecules of O2
- amount of O2 bound is dependent on partial pressure
- increase partial pressure = greater binding sites for O2 = greater percent saturation
- 1.34 ml O2 per gram of hemoglobin
- total content O2 blood = sum dissolved O2 content and hemoglobin bound O2 content
- 25% of O2 in hemoglobin delivered to the tissues in healthy subject at rest
- up to 75-80% can be delivered if need by
- systemic venous PO2 = 40mmHg
- systemic arterial PO2 = 100 mmHg


Effects on hemoglobin saturation

- increase concentration of 23DPG decreases O2 affinity of hemoglobin and shifts curve to the right
- increase temperature = decrease O2 affinity = curve to right
- increase acidity = decrease O2 affinity = curve shifts to right
- facilitating O2 release to tissues of body
- increase CO2 by RBC facilitates release O2 to body


Neural generation of Rhythmical breathing

- an OD of morphine, barbituates, or alcohol suppresses the neurons in the ventral resp group and stops respiration
- regions in CNS regulate breathing
- in medella: 2 main components DRG (dorsal resp. group) and VRG (ventral resp group)
- DRG fires during inspiration stimulating diapragm
- VRG fires in both inspiration and expiration
- pons provides input to respiratory center


Peripheral Chemoreceptors

- sensory feedback related to level of ventilation is provided by chemoreceptors
- peripheral receptors deal with PCO2
- hypoxcemia is low arterial CPO2
- peripheral chemoreceptors are in aortic bodies and carotid bodies



- can happen at high altitude
- occurs when decrease PO2, decrease alveolar PO2, decrease PO2 therefore increase chemoreceptor firingl, increase resp muscle contractions and therefore increase ventilation
- big contributor increase alveolar PCO2
- increase ventilation also increase with acid (lactic acid) to help decrease PPCO2 (called metabolic acidosis)



- ventilation increases and decreases abruptly at start and finish of exercise
- arterial PO2 and PCO2 and H+ don't change much
- hormones may have influence ventilation


Arterial Hypoxemia

- respiratory disease
- low arterial PO2


5 main causes of hypoxemia

- ambient hypoxia. low O2 in atmosphere
- alveolar hypoventilation b/c takes in less O2
- diffusion impairment because equilibrium may never be achieved
- physiologic shunt. blood doesn't pick up O2
- ventilation/perfusion mismatching b/c blood w/low PO2 is added to blood w/well ventilation, loweing overall



- inadquete O2 delivery to tissues
- pathology of emphysema is major cause of hypoxia


Anemic Hypoxia

- poor O2 delivery b/c of too few RBCs or abnormal hemoglobin


Ischemic Hypoxia

- blood circulation is impaired


Histotoxic Hypoxia

- body's cells are unable to use 2 (cyanide causes)


Hypoxemic Hypoxia

- reduced arterial O2 (can be cause by lack of oxygenated air, pulmonary problems, lack of ventilation perfusion coupling)


Carbon Monoxide Poisoning

- type of a hypoxemic hypoxia
- leading cause of death from fire
- CO = odorless, colorless gas competes with oxygen for binding sites and has 200X greater affinity for hemoglobin than O2
- symptoms: confusion, resp distress, skin becomes red
- no cyanosis is detectable
- treated with hyperbarics or 100% O2


Functions of Respiratory System

- provides O2
- eliminates CO2
- regulates blood's hydrogen ion concentration (pH) w/kidney
- forms speech sounds (phonation)
- defends against microbes
- influences aarterial concentrations of cemical messengers by removing some pulmonary capillary blood and producing and adding others to this blood
- traps and dissolves blood clots arising from systemic veins such as those in legs