Download The Respiratory System

PET 3322 Test 3 In-­‐ Class Review The Respiratory System •
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Ventilation: Movement of air into and out of lungs External respiration: Gas exchange between air in lungs and blood Transport of oxygen and carbon dioxide in the blood Internal respiration: Gas exchange between the blood and tissues Nasal cavity à Pharynx à Larynx à Trachea à Primary bronchi à Secondary bronchi à Tertiary bronchi àBronchioles à Alveoli Parts of Respiratory System • Nasal Cavity –interior part of nose • Pharynx –passageway for air/food, resonating chamber, stores tonsils • Larynx –Passage way for air between the pharynx and trachea -­‐includes the unpaired thyroid cartilage (aka Adam’s Apple) • Trachea –“Windpipe” • Primary bronchi –each extend to a lung (right is bigger than left) Carina triggers the cough reflex. • Secondary bronchi –lobar bronchi –within the lung (2 in left 3 in right) supply the lobes and segments of each lung • Tertiary bronchi –Segmental Bronchi • Bronchioles -­‐end in terminal bronchioles • Alveoli –Gas exchange between blood and air Where does gas exchange occur? • In the alveoli -­‐where gas exchange between the air and blood takes place. • All the branches from the trachea to the terminal bronchioles are conducting airways (they do not participate in gas exchange) What part of the upper respiratory system is used in digestion? • Pharynx –passage way for air and food. What happens at the Respiratory Membrane? • The respiratory membrane of the respiratory zone in the lungs is where gas exchange between the air and blood takes place. • It is formed mainly by the alveolar walls and surrounding pulmonary capillaries, with some contribution by respiratory bronchioles and alveolar ducts. • The respiratory membrane is very thin to facilitate diffusion of gases. • O2 and CO2 get across respiratory by SIMPLE DIFFUSION • Respiratory membrane has several layers o A thin layer of fluid lining the alveolus o The alveolar epithelium composed of simple squamous epithelium o A thin interstitial space o The basement membrane of the capillary endothelium o The capillary endothelium, composed of simple squamous epithelium Explain the gas exchange process –Respiration • External respiration (pulmonary) is gas exchange between the alveoli and the blood. PET 3322 Test 3 In-­‐ Class Review Internal respiration (tissue) is gas exchange between the systemic capillaries and the tissue of the body. Breathing during Expiration: • Quiet: Relaxation of the diaphragm, with/without contraction of the internal intercostal, decrease size of the thorax, increases the air pressure What causes how air flows in and out of lungs? Pressure gradient • Surface tension –causes the alveoli to assume the smallest possible diameter and accounts for 2/3 of lung elastic recoil • Lung compliance –high lung compliance means the lungs and chest wall expand easily • Airway resistance –the less airway resistance, the greater airflow Laws • Boyle’s Law –Volume and pressure are inversely related. Applies to containers with flexible walls (thoracic cage) o If there is an decrease in volume –there will be a increase in pressure • Dalton’s Law –Each gas is a mixture of gases exerts its own pressure as if no other gases were present • Henry’s Law –Quantity of a gas that will dissolve in a liquid is proportional to the partial pressures of the gas and its solubility o A higher partial pressure of a gas (O2) over a liquid (blood) means more of the gas will stay in the solution. • HOW EACH RELATES TO Oxygen–hemoglobin dissociation curve o The Bohr Effect and how it relates to respiration o Bohr Effect –The effect of pH on the oxygen-­‐hemoglobin dissociation curve. o As blood flows from the lungs toward the tissues, the increasing acidity (decrease of pH) increases H+ which decreases the hemoglobin’s ability to bind to oxygen. SHIFTS RIGHT. Enhancing unloading of O2 o Conversely, and increase in blood pH (less acidic) increases the hemoglobin’s ability to bind to oxygen. o With the Bohr effect, more oxygen is released because a(n) decrease in pH (acidosis) weakens the hemoglobin-­‐oxygen bond. The Haldane Effect and how it relates to respiration • Haldane Effect –As hemoglobin releases oxygen, the hemoglobin gains an increased ability to pick up carbon dioxide. • At the lungs, oxygenated blood has a reduced capacity to carry CO2, and it is unloaded as we exhale • The smaller the amount of oxygen bound to hemoglobin, the greater the amount of carbon dioxide able to bind to it, and vice versa. Know major regulator of respiration • Plasma concentration of CO2 • The most powerful respiratory stimulus for breathing in a healthy person is •
PET 3322 Test 3 In-­‐ Class Review increase of carbon dioxide. Oxygen movement in blood • Dissolved in blood plasma, bound to hemoglobin What effect does aging have on Respiration? Decreases: • Gas exchange across respiratory membrane • Ability to remove mucus from respiratory passageways • Vital capacity & maximum minute ventilation Increases: • Residual volume and dead space What are the receptors that are stimulated by extra CO2? • Peripheral chemoreceptor Carbon dioxide is transported as bicarbonate ions (70%) in combination with blood proteins (23%: primarily hemoglobin) and in solution with plasma (7%) Protective function of respiratory system is • Against microorganisms by preventing entry and removing them from respiratory surfaces. Know during exercise: how the oxygen and hemoglobin dissociation curve • Carotid bodies respond rapidly to changes in blood pH because of exercise • Ventilation increases abruptly o At onset of exercise o Movement of limbs has strong influence o Learned component • Ventilation increases gradually o After immediate increase, gradual increase occurs (4-­‐6 minutes) o Anaerobic threshold: highest level of exercise without causing significant change in blood pH. If exceeded, lactic acid produced by skeletal muscles