Lab Quiz 6 Respiratory Physiology

Respiration (gas exchange) occurs in 3 steps:

1. Pulmonary ventilation (breathing) -the mechanical flow of air into (inhalation) and out of (exhalation) the lungs. 2. External respiration -the exchange of gases between the air spaces of the lungs and the blood in the capillaries. 3.Internal respiration -the exchange of gases between the blood in systemic capillaries and tissue cells. Pulmonary ventilation (breathing) is the process by which gases flow between the atmosphere and the

Lung Cancer

Accounts for 1/3 of all cancer deaths in the U.S. 90% of all patients with lung cancer were smoker The three most common types are: Squamous cell carcinoma (20-40% of cases) arises in bronchial epithelium Adenocarcinoma (25-35% of cases) originates in peripheral lung area Small cell carcinoma (20-25% of cases) contains lymphocyte-like cells that originate in the primary bronchi and subsequently

Pressure Changes During Pulmonary Ventilation

Air moves into the lungs when air pressure in the atmosphere is greater than air pressure in the lungs. Air moves out of the lungs when the pressure inside the lungs is greater than the pressure in the atmosphere.

Transport and Exchange of Carbon Dioxide at tissues

At the tissues: - Bicarbonate quickly diffuses from RBCs into the plasma - The chloride shift occurs to counterbalance the outrush of negative bicarbonate ions from the RBCs, chloride ions (Cl-) move from the plasma into the erythrocytes

Muscles Of Inhalation

Diaphragm (most important) External intercostals.

Breathing Patterns

Eupnea -a normal pattern of quiet breathing. Costal breathing -shallow (chest) breathing. An upward and outward movement of the chest due to contraction of the external intercostal muscles. Diaphragmatic breathing -deep (abdominal) breathing consisting of outward movement of the abdomen from contraction and descent of the diaphragm

Chronic Obstructive Pulmonary Disease (COPD)

Exemplified by chronic bronchitis and obstructive emphysema Patients have a history of: - Smoking - Dyspnea, where labored breathing occurs and gets progressively worse - Coughing and frequent pulmonary infections COPD victims develop respiratory failure accompanied by hypoxemia, carbon dioxide retention, and respiratory acidosis

Active Exhalation

Exhalation becomes active only during forceful breathing such as when playing a wind instrument or during exercise. The muscle of exhalation then contract. Abdominals. Internal intercostals.

External Respiration

External Respiration External respiration or pulmonary gas exchange is the diffusion of O2 from air in the alveoli of the lungs to blood in pulmonary capillaries and the diffusion of CO2 in the opposite direction. External respiration converts deoxygenated blood coming from the right side of the heart into oxygenated blood that returns to the left side of the heart. External respiration occurs only in the lungs

Influence of Carbon Dioxide on Blood pH

The carbonic acid-bicarbonate buffer system resists blood pH changes •If hydrogen ion concentrations in blood begin to rise, excess H+ is removed by combining with HCO3 - •If hydrogen ion concentrations begin to drop, carbonic acid dissociates, releasing H+ Changes in respiratory rate can also: - Alter blood pH - Provide a fast-acting system to adjust pH when it is disturbed by metabolic factors

Boyles Law

The pressure of a gas in a closed container is inversely proportional to the volume of the container. If the size of a closed container increases, the pressure inside the container decreases. If the size of a closed container decreases, the pressure inside the container increases.

tidal volume

Tidal volume (VT)-the volume of one breath.

Transport and Exchange of Carbon Dioxide at lungs

Transport and Exchange of Carbon Dioxide At the lungs: (reversed) - Bicarbonate ions move into the RBCs and bind with hydrogen ions to form carbonic acid - Carbonic acid is then split by carbonic anhydrase to release carbon dioxide and water - Carbon dioxide then diffuses from the blood into the alveo

lung volume capacity

Typically, about 70% of the tidal volume reaches the respiratory portion of the respiratory system. The remaining airways are known as the anatomical dead space (150ml). By inhaling deeply, you can take in additional air (inspiratory reserve volume).

the expiratory reserve volume

is the additional air from a forced exhale.

vital capacity

is the sum of inspiratory reserve volume, tidal volume, and expiratory reserve volume.

the functional residual capacity

is the sum of residual volume and expiratory reserve volume.

inspiratory capacity

is the sum of the tidal volume and the inspiratory reserve volume.

total lung capacity

is the sum of vital capacity and residual volume.

Respiratory Sounds

1. Bronchial sounds -produced by air rushing through the trachea and the bronchi 2. Vesicular breathing sounds -produced by air filling the alveolar sacs and resembles the sound of a rustling or muffled breeze.

spirogram

A spirogram is the record of this volume.

spirometer

A spirometer or respirometer are utilized to measure the volume of air used.

Inhalation

Breathing in is called inhalation (inspiration). Increasing the volume of the lungs causes inhalation. Contraction of the diaphragm and the external intercostals expands the lungs

Exhalation

Breathing out is called exhalation or expiration Elastic recoil of the chest wall and lungs causes exhalation. Recoil of the elastic fibers that were stretched during inhalation. The inward pull from surface tension of the film of alveolar fluid.

Asthma

Characterized by dyspnea, wheezing, and chest tightness Active inflammation of the airways precedes bronchospasms Airway inflammation is an immune response caused by release of IL-4 and IL-5, which stimulate IgE and recruit inflammatory cells Airways thickened with inflammatory exudates magnify the effect of bronchospasms

Chemoreceptor Regulation

Chemoreceptors regulate the levels of O2 and CO2. Central chemoreceptors are located in the medulla oblongata. Peripheral chemoreceptors are located in the aortic bodies and carotid bodies.

Tuberculosis

Infectious disease caused by the bacterium Mycobacterium tuberculosis Symptoms include fever, night sweats, weight loss, a racking cough, and splitting headache Treatment entails a 12-month course of antibiotics

Internal Respiration

Internal respiration or systemic gas exchange is the exchange of CO2 and O2 between the systemic capillaries and tissue cells. Internal respiration occurs in tissues throughout the body.

minute ventilation

Minute ventilation (MV) is the volume of inhaled and exhaled air in one minute. It is determined by multiplying the respiratory rate by the tidal volume.

Oxygen Transport

Oxygen does not dissolve easily in water. Most of the blood O2 is bound to hemoglobin. Oxygen and hemoglobin bind in an easily reversible reaction to form oxyhemoglobin

Partial Pressure Gradients and Gas Solubilities

Partial Pressure Gradients and Gas Solubilities •The partial pressure oxygen (PO2) of venous blood is 40 mm Hg; the partial pressure in the alveoli is 104 mm Hg - This steep gradient allows oxygen partial pressures to rapidly reach equilibrium (in 0.25 seconds), and thus blood can move three times as quickly (0.75 seconds) through the pulmonary capillary and still be adequately oxygenated •Although carbon dioxide has a lower partial pressure gradient: - It is 20 times more soluble in plasma than oxygen - It diffuses in equal amounts with oxygen

Respiratory Center

Respiratory Center The respiratory center in the brain stem controls the basic rhythm of respiration. 3 areas: Medullary rhythmicity area -controls the basic rhythm. Inspiratory and expiratory areas. Pneumotaxic area -impulses turn off the inspiratory area before the lungs become too full. Apneustic area -activates the inspiratory center and prolongs inspiration.

Factors Affecting Pulmonary Ventilation

Surface tension of alveolar fluid. A deficiency in surfactant in premature infants causes respiratory distress syndrome. Compliance of lungs refers to how much effort is required to stretch the lungs. Decreased compliance results from scar tissue (TB), excess fluid (pulmonary edema), a deficiency in surfactant, or paralysis of muscles of inspiration. Airway resistance -any condition that narrows or obstructs airways increases resistance. - Can prevent life-sustaining ventilation - Can occur during acute asthma attacks which stops ventilation • Epinephrine release via the sympathetic nervous system dilates bronchioles and reduces air resistance

residual volume.

even after a forced breath, some air remains.

Carbon Dioxide Transport

•Carbon dioxide is transported in the blood in three forms - Dissolved in plasma -7 to 10% - Chemically bound to hemoglobin -20% is carried in RBCs as carbaminohemoglobin - Bicarbonate ion in plasma -70% is transported as bicarbonate (HCO3 -) ione