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Respiratory System

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icer215's version from 2016-08-18 01:46

Section 1

Question Answer
VentilationSimple movement of air into and out of the lungs
RespirationExchange of gases (O2 and CO2) between either the lungs and the blood or the blood and the other tissues of the body
pH regulationIn blood, CO2 is converted to carbonic acid by the RBC enzyme carbonic anhydrase CO2 is exhaled by the lungs, the amount of carbonic acid in the blood is decreased, and as a result the increase in pH of the blood (more alkaline)
Hyperventilationtoo much breathing causes alkalinzation of the blood known as “respiratory alkalosis”
Hypoventilationtoo less breathing causes acidification of the blood known as “respiratory acidosis”
ThermoregulationBreathing causes important heat loss.Ex: Dogs depend on panting for dissipation of excess heat because they cannot sweat
Protection from disease and particular matterLungs (mucociliary escalator and alveolar macrophages) provide a large moist surface where chemicals and pathogens can do no harm
LungsPair of organs (left and right) with spongy structure filled with air Located on the chest Covered by tissue layer called pleura
TracheaConduct inhaled air into the lungs through its tubular branches Passageway that must remain open to permit air flow Rings of cartilage prevent its collapse Branches into two primary bronchi, each supplies one lung Each bronchus branches repeatedly to supply the entire lung
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Section 2

Question Answer
Respiratory zoneparts that participate in actual gas exchanges
Alveolus (alveoli for plural)Where gases diffuse At the end of each alveolar duct The wall is only one cell think, except where capillaries pass across its outer surface.
Alveolar ductsThe duct leading to the alveoli and its walls are entirely made of alveoli
Respiratory bronchioleA tube made of smooth muscle (similar to terminal bronchiole.s) but the respiratory bronchioles has a few alveoli scattered in its walls, which allows it to perform gas exchange.Contain no cartilage The walls are made of smooth muscle which allows their diameter to be regulated to adjust airflow into the system
Terminal bronchiolessmallest and final branches of the conduction zone
Smooth muscles of the walls is too thick to allow adequate diffusion of gases, so no gas exchange occurs; only for ventilation
Inhaled air pathway goesNose ➙ nasal cavity ➙ pharynx ➙ larynx ➙ trachea ➙ bronchi ➙ terminal bronchioles ➙ respiratory bronchioles ➙ alveolar ducts ➙ alveoli
Noseimportant for warming, humidifying, and filtering inhaled air
Nasal hairs and sticky mucusact as filters.They filter foreign particles from entering the nasal cavity and collecting moisture The airways is lined with sticky mucus that trap any particles like dust, pollutants, bacteria, and more Cilia, small hairs, weeps mucus from the nasal cavity into the back of the throat to be swallowed into the stomach We produce 2 to 4 cups of mucus per day
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Question Answer
Nasal cavityopen space within the nose
Pharynxthroat, a common pathway for air and food, at the bottom of which is the larynx
Larynxmade entirely of cartilage and keeps the airway open, contains the epiglottis that seals the trachea during swallowing to prevent the entry of food, and it contains vocal cords that are folds of tissues positioned to partially block the flow of air and vibrate in producing sound
DiaphragmMuscle right below the lungs
During inhalationdiaphragm contracts, moving down
During exhalationdiaphragm relaxes, moving up
Rib cageBones that protect and provide structure for lungs
During inhalationrib cage expands and rib muscles contract
During exhalation rib cage gets smaller and rib muscles relax
Differential pressurebetween inside and outside the lungs
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Section 3

Question Answer
Intrapulmonary pressureThe pressure within the alveoli When this pressure is lower than atmospheric pressure, air moves into the alveoli = inhalation When this pressure is greater than atmospheric pressure, air moves out of the alveoli = expiration
Intrapleural pressureThe pressure within the pleural cavity (lungs) Always negative to keep the lungs inflated Always less than the intrapulmonary pressure
ResiliencyLungs are elastic, so the stretch and relax
Surface tension effectsWhen alveoli are as fine and delicate as tissue paper, and they too tend to collapse due to surface tension. Thus soapy substance (mixture of phospholipids, proteins, and ions) called surfactant solves the problem by coating the alveoli
Breathing causes significant heat loss
Evaporation at the capillary beds (moist)Mechanism to lose heat
Panting increases respiratory rateLoses carbon dioxide from the body, so loses heat
DiffusionMain mechanism of gas and solute exchange Molecules will move from higher concentration to lower concentration (down the gradient) Larger the surface area, the faster the speed of diffusion
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Question Answer
OxygenLower in the alveoli when compared to the external environment Allows diffusion of oxygen into the alveoli
Carbon dioxideHigher in the capillaries than in the alveoli Allows for diffusion into the alveoli to be exhaled
Henry’s LawSays that when gas is in contact with the surface of a liquid, the amount of the gas will go into the solution is proportional to the partial pressure of that gas
Concentration (c) = P/KHKH: constant with the dimensions of pressure divided by concentration P: partial pressure of the solute in the gas
The pH of blood can be controlled by respiration systemIncrease in carbon dioxide concentration leads to decrease in the pH of blood because carbon dioxide becomes carbonic acid in an aqueous environment
When decrease in blood pH is recognized by central chemoreceptors
Central chemoreceptorsare found on the ventrolateral surface of medulla oblongata
Chemoreceptorsensory receptor that detects the levels of carbon dioxide in the blood
Respiratory center in the medulla sends nervous impulse to the external intercostal muscles and the diaphragm to increase breathing rate and the volume of the lungs during inhalation
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Section 4

Question Answer
Proper regulation of the rate of breathing is essential
Respiratory control centerAlthough breathing can be voluntarily controlled for short periods of time, it is normally an involuntary process directed by this control center in the medulla of the brain stem
The stimuli affectsventilation rate that are both mechanical and chemical
Chemical stimuliCO2 + H2O ⇌ H2CO3 ⇌ H+ + HCO3– Ventilation rate are increase PCO2 (partial pressure of gas CO2), decreased pH, and decrease PO2, which are monitored by special autonomic sensory receptors
Mechanical stimuliAffect ventilation rate include physical stretching of the lungs and irritants
Bronchoconstrictioncontraction of smooth muscle (of wall of bronchi and large bronchioles)
Irritant receptorstrigger coughing and/or bronchoconstriction when an irritation chemical is detected
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