SLHS 11500 Chapter Notes - Chapter Unit 2: Serratus Anterior Muscle, Sternocleidomastoid Muscle, Alveolar Pressure
25 Aug 2016
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SLHS 115 Notes U2
Ch. 3 Anatomy and Physiology
• Anatomy: structure
•Physiology: function
• Respiratory System:
• Primary Function: supply oxygen to the blood and remove excess carbon dioxide
• Secondary Function: generates potential energy source for sound production
• Structures:
• lungs: air-filled sacs that change in size and shape to allow us to breathe
•trachea: “wind pipe”, how air moves to and from lungs
• Muscles:
• inspiratory muscles: found above diaphragm
•diaphragm: dome-shaped structure composed of a thin, flat,
nonelastic central tendon and a broad rim of muscle fibers that radiate
up to the edges, contacts during inspiration and pulls down drawing
air into the lungs
• expiratory muscles are located below the diaphragm (see diagram pg. 45)
• pectoralis muscles (minor and major)
• sternocleidomastoid muscle
• scalenes muscle
• serratus anterior muscle
• muscular involvement may change due to body position, pathological
state and environmental conditions
•Resting Tidal Breathing: quiet breathing or breathing to sustain life
•alveolar pressure: pressure within the lungs
• inspiration: contraction of the diaphragm leads to expansion of the rib
cage which causes expansion of the lungs which causes an increase
in lung volume and decrease in alveolar pressure making it lower than
atmospheric pressure, thus drawing in air
• expiration: decrease in the size of the rib cage which compresses the
lungs which increases the alveolar pressure which causes air to rush
out of the lungs to reach equilibrium, does NOT require muscular
contraction, it is achieved by gravity and muscles returning to relaxed
state
• Speech Breathing:
• contraction of the diaphragm produces rapid, forceful inspirations
• time spent inhaling is short relative to time spent exhaling
• active muscle contraction of both inspiratory and expiratory muscles is
needed during speech production
• Lifespan Issues:
• number of alveoli increase as you age, allowing for shorter and less frequent
breaths
• lung capacity also increases with age
• respiratory function is affected by: age, exercise, health and smoking
• Phonatory System:
•larynx: air valve composed of cartilages, muscles and other tissue, principal sound
generator for speech production, “voice box” (sits on top of trachea and opens up
into the pharynx)
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