SLHS 261 Lecture 7 Outline of Last Lecture I. Muscles of Inspiration and ExpirationOutline of Current Lecture II. Forces can cause movementsA. Rib Cage Wall Movementsi. Pump handle movement increase the front to back dimension of the rib cageii. Bucket handle movement increase the side to side dimension of the rib cage B. Diaphragm Movementsi. The diaphragm flattens when it contracts and domes when it relaxesii. The diaphragm flattens by descent of the central tendon andor by the elevation of the ribs iii. At the top of deep breathing, the diaphragm is flativ. When the rib cage is kept still, the diaphragm pushesthe abdomen out v. The diaphragm pushes the rib cage lifts the rib cagewhen the abdomen is kept stillvi. The domes when the abdomen is pulled inC. Abdominal Wall Movementsi. Abdominal muscles are only expiratoryii. When the abdominal wall moves in, the diaphragm domes,and the rib cage wall enlargesD. Rib cage movements compared to Abdominal Wall Movementsi. The rib cage is much more efficient in changing the volume of thelungs and pressure inside the lungs than the abdomen, because the rib cage covers a greatersurface (3/4) of the pulmonary apparatusIII. Lung capacities A. Resting Tidal Volume: Allows us to ventilate (move air in and out of the alveoli) andengage in gas exchange (at the level of the alveoli)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.i. Alveolar pressure becomes negative (up to about -1 cmH2O) during inspiration andbecomes positive (up to about +1 cmH2O) during expiration ii. This is because the lungs expand during inspiration and the air molecules are fartherspread apart. The positive pressure has to do with the lung volume decreaseB. Vital Capacity- the total amount of air you can use. Measured by breathing in the biggestbreath possible and exhaling as much as possibleC. Residual Volume- Volume that is left over after vital capacity and can not be exhaled(unless you’re run over a truck or your lungs collapse)IV. Chest Wall ShapesA. Inverted Pear- Rib Cage is out and Abdomen is in- this is the chest wall shape used during conversational speech Current