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Respiratory System
Review of Physiology & Basic Anatomy
60
Anatomy
Undergraduate 2
03/10/2008

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Cards

Term
What is respiration?
Definition
Gas exchange between atmosphere, blood, and cells.
Term
What is pulmonary ventilation?
Definition
The movement of air into and out of lungs, breathing.
Term
What is external respiration?
Definition
Gas exchange between blood and the lungs.
Term
What is internal respiration?
Definition
The gas exchange between blood and tissue in the body.
Term
What is the function of pleural fluid?
Definition
Allows lungs to slide within thorax during breathing, separation between pleurae creates surface tensions so lungs cling to thoracic wall.
Term
Where do lungs extend?
Definition
From the diaphragm to slightly superior of clavicles.
Term
What is the general anatomy of the right lung?
Definition
3 lobes (superior, middle, and inferior), with an oblique and horizontal fissure.
Term
What is the general anatomy of the left lung?
Definition
2 lobes (superior and inferior), with one oblique fissure and a depression for the heart.
Term
What is the ordering of bronchi?
Definition
Primary, secondary, and tertiary (segmental).
Term
Each segmental bronchi supplies how many of what?
Definition
Bronchopulmonary segments (about 10), which contain many small lobule compartments - the smallest visible unit.
Term
What are alveoli?
Definition
Small sacs where gas exchange occurs, surrounded by elastic fibers.
Term
What connects alveoli?
Definition
Alveolar pores.
Term
What engulfs pathogens in the lungs?
Definition
Alveolar macrophages, dust cells.
Term
What are type I cells in the lungs?
Definition
Simple squamous endothelial cells of the alveoli.
Term
What does the respiratory membrane allow for?
Definition
Gas exchange between air on the alveolar side, and blood on the capillary side.
Term
What are type II cells in the respiratory cells?
Definition
Cuboidal cells that secrete fluid (surfactant) which prevents collapse of alveoli during expiration.
Term
What are the two phases of pulmonary ventilation?
Definition
Inspiration and expiration.
Term
What is intrapulmonary pressure?
Definition
Pressure within the alveoli, rises and falls with breathing, but always equalizes with atmospheric pressure.
Term
What is intrapleural pressure?
Definition
The pressure within the pleural cavity, fluctuates with breathing but ALWAYS ~ 4 mmHg less than alveolar pressure.
Term
Why is the intrapleural pressure always less than alveolar pressure?
Definition
Because of the natural elasticity of lungs and their tendency to recoil to smallest size, surface tension of alveolar fluid that draws alveoli into smallest position.
Term
What is transpulmonary pressure?
Definition
The difference between intrapulmonary and intrapleural pressure, keeps the lungs from collapsing.
Term
What is the technical term for a collapsed lung?
Definition
Ateletasis.
Term
What are the two steps of inspiration?
Definition
The diaphragm contracts, followed by intercostal muscles which lift rib cage and sternum to expand thoracic volume even more.
Term
What other muscles become involved during forced inspiration?
Definition
Sternocleidomastoid, scalenes, and pectoralis minor all act to increase thoracic volume.
Term
What muscles aid in forced expiration?
Definition
Obliques and transversus abdominis, as well as internal intercostals.
Term
What must alveolar overcome in order to expand?
Definition
Surface tension within them. Surfactant is a mixture of lips and proteins that reduces surface tension.
Term
What occurs in infant respiratory distress syndrome?
Definition
Too little surfactant, requires ventilation and surfactant replacement.
Term
What is compliance of the lungs?
Definition
Distensibility, the ease with which lungs and thoracic wall expand.
Term
What is Henry's Law?
Definition
A mixture of gases in contact with a liquid will dissolve in such a way that it is proportionate to its partial pressures.
Term
What is the most soluble gas?
Definition
CO2!
Term
What is an insoluble gas?
Definition
N2
Term
What is nitrogen narcosis?
Definition
N2 accumulation in lipids, esp. the CNS fatty tissue - causes dizziness.
Term
CO2 is how many times more soluble than O2 in the blood?
Definition
20 times more soluble than O2
Term
What occurs in a high alveolar O2?
Definition
Arterioles dilate to increase uptake of O2.
Term
At rest how much of available oxygen from blood enters cells?
Definition
About 25 % enters tissue cells.
Term
What happens to hemoglobin as the pressure of O2 is increased?
Definition
It is loaded with oxygen until its maximum potential is reached.
Term
What factors effect hemoglobin's affinity for O2?
Definition
Increased temperature, H+ content, and pressure of CO2.
Term
What occurs in an acidic environment?
Definition
The Bohr shift - O2 readily splits from hemoglobin because a decreased pH weakens O2-Hemoglobin bond.
Term
What happens to hemoglobin as temperature is increased?
Definition
The amount of O2 released from hemoglobin increases.
Term
What is the problem with CO and hemoglobin?
Definition
It's affinity for hemoglobin is 200x stronger than oxygen's - can severely reduce oxygen carrying capacity of the protein.
Term
How is CO2 transported in blood?
Definition
Dissolved in plasma (least), carbaminohemoglobin (bound to globin, middle), and bicarbonate ions which dissociate into H+ and HC03- (most of all).
Term
What happens as CO2 is converted to bicarbonate?
Definition
The chloride shift, as HCO3 leaves Cl enters RBC's, maintaining ionic balance between plasma and RBC
Term
What happens as CO2 enters the blood?
Definition
Causes O2 to split from hemoglobin, lowers blood pH as H+ increases.
Term
What happens as O2 binds to hemoglobin with respect to CO2?
Definition
CO2 is released from the blood.
Term
Where is the respiratory center of the brain?
Definition
In the reticular formation of the medulla and pons.
Term
What is the inspiration pacesetter?
Definition
The dorsal respiratory group.
Term
What suppresses the medullary respiratory center?
Definition
Sleeping pills, alcohol, and morphine, supress this center.
Term
What are expiratory area neurons?
Definition
Inactive during most quiet respiration, activated during high ventilation, causes contraction of forced expiration muscles.
Term
What is the ventral respiratory center responsible for?
Definition
Expiratory mechanisms.
Term
What are the pons respiratory centers responsible for?
Definition
Smoothing transitions between inspiration and expiration, fine tuning of rhythm.
Term
What is the pneumotaxic center?
Definition
Inhibits medullary inspiratory center to prevent lung overinflation.
Term
What is the apneustic center?
Definition
Stimulates medullary inspiratory center to prolong inspiration.
Term
How does chemical regulation occur to regulate H+, CO2, and O2 levels in arterial blood?
Definition
Central chemoreceptors (medulla), and peripheral chemoreceptors (aortic arch and carotid arteries)
Term
What are central chemoreceptors?
Definition
Respond to changes in H+ / pressure of CO2 in CSF.
Term
What is hypercapnia?
Definition
CSF pH decreased, stimulates respiratory center.
Term
What are peripheral chemoreceptors?
Definition
Respond to changes in O2 pressure in arteries.
Term
What is the most important stimulus for breathing in a healthy person?
Definition
Getting rid of CO2
Term
What happens if the pressure of CO2 is too low?
Definition
Hypocapnia, CO2 must accumulate to trigger respiration.
Term
What is a long term adjustment to high altitude?
Definition
Kidneys produce more erythropoietin to stimulate RBC production.
Term
What is emphysema?
Definition
Alveoli lose elasticity, causes lung fibrosis.
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