A&P II Unit 3 (Ch. 22) Objectives

Name the muscles primarily responsible for the volume changes during normal breathing & during physical exertion.

1. Inspiration: a. ***sternocleidomastoid (elevates sternum) b. ***scalenes (fix ribs 1-2) c. *external intercostals (elevate ribs 2-12; widen thoracic cavity) d. ***pectoralis minor (elevates ribs 3-5) e. internal intercostals, intercartilaginous part (aid in elevating ribs) f. *diaphragm (descends and increases depth of thoracic cavity) 2. Expiration: (relaxation of inspiratory muscles) a. ***internal intercostals, interosseous part (depress ribs 1-11, narrow thoracic cavity) b. *diaphragm (ascends and reduces depth of thoracic cavity) c. ***rectus abdominus (depresses lower ribs, pushes diaphragm upward by compressing abdominal organs) d. ***external abdominal oblique (same as rectus) *principal respiratory muscles ***during forceful breathing

Know the relationship between pressure/volume related to inspiration/expiration.

An increase in pressure results in a decrease in volume; decrease in pressure results in an increase in volume (Boyle's law: volume of gas varies inversely with pressure, assuming temperature is constant) During inspiration (air flows into the lungs), the thoracic cavity expands, intrapulmonary pressure drops below atmospheric pressure, air flows in, increasing the volume. During expiration (gases exit the lungs), the thoracic cavity contracts, intrapulmonary pressure rises above atmospheric pressure, air flows of of the lungs, decreasing volume. Intrapulmonary pressure always eventually equalizes itself with atmospheric pressure Intrapleural pressure is always less than intrapulmonary and atmospheric

Given an oxygen dissociation curve, determine the percent of hemoglobin saturation with oxygen for a given PO2 & PCO2; discuss the influence of the Bohr effect on hemoglobin saturation.

Bohr effect: active tissue has an increase in CO2, which raises H+ and lowers pH, O2 is released; dissociation curve under normal

Systemic Gas Exchange

CO2 loading -carbonic anhydrase in RBC catalyzes: CO2 + H2O --> H2CO3 --> HCO3-+ H+ -chloride shift: keeps reaction proceeding, exchanges HCO3-for Cl-(H+ binds to hemoglobin) O2 unloading -H+ binding to HbO2 decreases its affinity for O2; Hb arrives 97% saturated, leaves 75% saturated-venous reserve -utilization coefficient; amount of oxygen Hb has released 22%

Recognize &/or give the cause & disease process for the following:

Chronic Obstructive Pulmonary Disease (COPD) ---emphysema: alveolar walls break down; much less respiratory membrane for gas exchange; lungs fibrotic and less elastic; air passages collapse and obstruct outflow of air; air trapped in lungs ---chronic bronchitis: cilia immobilized and decrease in number; goblet cells enlarge and produce excess mucus; sputum formed which is ideal growth media for bacteria; chronic infection and bronchial inflammation develop ---asthma: spasms of smooth muscle in broncial tubes that result in partial or complete clsure of air passageways; inflammation; inflated alveoli; excess mucus production (allergy, emotions, aspirin, exercise, cold air, smoking) pneumonia: acute infection of alveoli; most common cause is pneumococcal bacteria (treatment: antibiotics, bronchodilators, oxygen therapy, chest physiotherapy) cystic fibrosis: inherited disease of secretory epithelia; affects respiratory passageways, pancreas, salivary glands, sweat glands tuberculosis (TB): inflammation of pleurae and lungs produced by M. tuberculosis; communicable; destroys lung tissue leaving nonfunctional fibrous tissue behind bronchiogenic carcinoma: bronchial epithelial cells replaced by cancer cells after constant irritation has disrupted normal grown, division, and function of epithelial cells; airways blocked; metastasis common

Oxygen Transport

Concentration in arterial blood; 20 ml/dl,(98.5% bound to hemoglobin,1.5% dissolved) Binding to hemoglobin; each heme group of 4 globin chains may bind O2; oxyhemoglobin (HbO2 ), deoxyhemoglobin (HHb)

Define partial pressure & compute the partial pressures of gases in a mixture.

Dalton's Law: total atmospheric pressure is a sum of the contributions of these individual gases partial pressure is the separate contribution of each gas in a mixture If atmospheric pressure is 760 mm Hg then PN2 is 0.786 X 760 mm Hg = 597 mm Hg PO2 is 0.209 X 760 mm Hg = 159 mm Hg PH2O is 0.005 X 760 mm Hg = 3.8 mm Hg PCO2 is 0.0004 X 760 mm Hg = 0.3 mm Hg

Name three ways the thorax increases in volume during inspiration & decreases in volume during expiration.

During Inspiration: 1. diaphragm and external intercostals contract and rib cage rises 2. lungs are stretched and intrapulmonary volume increases 3. intrapulmonary pressure drops below atmospheric 4. air flows into lungs, down pressure gradient During Expiration: 1. inspiratory muscles relax and rib cage descend due to gravity 2. thoracic volume decreases 3. lungs recoil passively and intrapulmonary volume decreases 4. intrapulmonary pressure rises above atmospheric 5. gases flow out of lungs down pressure gradient

Recognize four reasons why oxyhemoglobin is induced to release oxygen in tissue capillaries.

Higher conc. of oxygen in hemoglobin than tissue H+ ions make hemoglobin let go of oxygen Higher temps make hemoglobin let go of oxygen Hemoglobin has low affinity for oxygen in first place

List & give the percentage of the main gases of the atmosphere.

Nitrogen = 79% (78.6) Oxygen = 21% (20.9) Carbon Dioxide = 0.04% Water Vapor = 0.5%

Name the ways carbon dioxide & oxygen are transported by the blood.

Oxygen binds to the 4 globin chains of a heme group (oxyhemoglobin HbO2; deoxyhemoglobin HHB); after binding oxygen, hemoglobin changes shape to facilitate further uptake (positive feedback cycle) Oxyhemoglobin dissociation curve is the relationship between hemoglobin saturation and PO2; it is not linear. PO2 in the systemic tissues is about 40 mm Hg, about 75% saturated; PO2 in the alveoli is about 100 mm Hg, 100% saturated Carbon dioxide can be transported as carbonic acid (*70%), carbaminohemoglobin (HbCO2)(*23%)(binds to amino groups of Hb (and plasma proteins)) and dissolved gas (7%) *alveolar exchange of CO2

Explain & interpret the movement of gases between alveolar spaces, blood & cells due to differences in partial pressure.

Partial pressures determine the rate of diffusion of gas and gas exchange between the blood and alveolus. Atmospheric PP: ---N2 = 597 ---O2 = 159 ---H2O = 3.7 ---CO2 = 0.3 Alveolar Air PP: ---N2 = 569 ---O2 = 104 ---H2O = 47 ---CO2 = 40 Blood PP: ---O2 = 40 ---CO2 = 46 Henry's Law: amount of gas that dissolves in water is determined by its solubility in water and its partial pressure in air Time required for gases to equilibrate = 0.25 seconds (O2 loading: more O2 in air than in blood; air moves down pressure gradient; reaches equilibrium) (CO2 unloading: more CO2 in blood than in air; CO2 moves down pressure gradient; reaches equilibrium) Factors affecting exchange: concentration gradients; gas solubility (CO2 is 20 times as soluble as O2); membrane thickness; membrane surface area; ventilation-perfusion coupling (vasodilation)

Carbon Dioxide Transport

carbonic acid: CO2 + H2O --> H2CO3 --> HCO3-+ H+ carbaminohemoglobin (HbCO2): binds to amino groups of Hb (and plasma proteins) dissolved gas alveolar exchange of CO2: carbonic acid - 70%; carbaminohemoglobin - 23%; dissolved gas - 7%

Recognize or define the following; analyze how each affects the respiratory system:

eupnea: normal variation in breathing rate and depth hyperventilation: carbon dioxide decreases in blood and raises pH; leads to respiratory alkalosis (caused by strong emotions of pain, anxiety, fear, panic; brain tumor or injury) apnea: breath holding hypoventilation: carbon dioxide builds up in blood (more acid (H+) ) and decreases pH; leads to respiratory acidosis (any condition that impairs breathing; impaired lung function (chronic bronchitis, cystic fibrosis, emphysema); impaired lung movement (chest injury, extreme obesity); narcotic or barbiturate overdose or injury to brain stem(depression of respiratory centers); most common cause of acid-base imbalance) Injuries to the chest wall that let air enter the intrapleural space ---causes pneumothorax ---atelectasis: collapse of lung (or part of lung) ---surface tension and recoil of elastic fibers causes the lung to collapse dyspnea: painful or difficult breathing anoxia: total depletion of tissue oxygen shortness of breath (SOB): "feeling thirsty for air"

***Write reactions to show the formation of each of the following in the blood; define & discuss the functional significance of each:

oxyhemoglobin carbonic acid carboxyhemoglobin carbaminohemoglobin bicarbonate ion

Distinguish between pulmonary ventilation, external & internal respiration.

pulmonary ventilation: moving air into and out of the lungs external respiration: gas exchange between the lungs and the blood internal respiration: gas exchange between the systemic blood vessels and tissues

Alveolar Gas Exchange

reactions are reverse of systemic gas exchange CO2 unloading: -as Hb loads O2 its affinity for H+ decreases, H+dissociates from Hb and bind with HCO3- -CO2 + H2O <-- H2CO3 <-- HCO3-+ H+ -reverse chloride shift -HCO3-diffuses back into RBC in exchange for Cl-, free CO2 generated diffuses into alveolus to be exhaled

Identify each of the following & indicate their normal values for an adult as given in the text & calculate the value of each using a spirogram:

tidal volume (TV): amount of air inhaled and exhaled in one cycle during quiet breathing (500 mL) (peak - valley of 3rd normal breath) residual volume (RV): amount of air remaining in the lungs after maximum expiration; the amount that can never voluntarily be exhaled (1300 mL) (lowest point of deep expiration) inspiratory reserve volume (IRV):amount of air in excess of TV that can be inhaled with maximum effort (3000 mL) (peak of deep inspiration - peak of last normal breath) vital capacity (VC): the amount of air that can be inhaled and then exhaled with maximum effort; the deepest possible breath (ERV+IRV+TV) (4700 mL) (peak of deep inspiration - valley of deep expiration) respiratory minute volume (RMV): total volume of air taken in during one minute (TVx12 breaths/min) (6000 mL/min) total lung capacity (TLC): maximum amount of air the lungs can contain (RV+VC) (6000 mL) (peak of deep inspiration) expiratory reserve volume (ERV): amount of air in excess of tidal volume that can be exhaled with maximum effort (1200 mL) (lowest point of normal breath - lowest point of deep expiration) respiratory rate (RR): breaths per minute (12 bpm)