respiratory structure & function

respiration

exchange of gas between organism and environment

process of respiration

provides energy for speech

skeletal framework

protects and anchors respiratory system
upper: ribs, sternum, shoulder/pectoral girdle (clavicles and scapulae)
lower: hips and pelvis
vertebral column serves as a post at the midline holding the framework together

respiratory system

made up of the pulmonary apparatus and chest wall

pulmonary appartus

consists of: lower airway and lungs

passive air reservoir

chest wall

consists of: rib cage wall, diaphragm, abdominal wall, and abdominal content

active pump that moves air in/out

lower airways

complex network of tubes that moves air in and out of the lungs

lungs

porous and spongy
5 lobes, 3 on the right and 2 on the left (gas exchange occurs)
covered by thin membrane called visceral pleura (acts as lubrication; allows for fluid motion)
inner chest wall covered by thin membrane called parietal pleura
“pleural linkage” connects lungs to chest wall

rib cage wall

surrounds the lungs

barrel shaped

includes the thoracic segments of the vertebral column, the ribs, costal cartilage, sternum, and pectoral girdle

diaphragm

forms the floor of the thorax and roof of the abdomen

dome shaped, inverted “bowl”

made of muscle and a central tendon

moves down with inhalation and up with exhalation

abdominal wall

consists of 15 vertebrae (lumbar, sacral, coccygeal), pelvic girdle, muscles, and connective tissue (abdominal aponeurosis and lumbodorsal fascia)

abdominal content

includes stomach, intestines, etc.

suspended from undersurface of diaphragm by suction force

the unit

the partnership between the pulmonary apparatus and the chest wall make breathing and speech possible

passive force

comes from the natural recoil of lungs, rib cage, and tissues

always present

active force

comes from muscle contractions of the chest wall

requires effort

muscles of inspiration

diaphragm, external intercostals, sternocleidomastoid, scalenes (anterior, middle, posterior), pectoralis major & minor, serratus anterior & posterior superior

diaphragm

the main muscle of inspiration (contracts down to expand the thoracic cavity)

external intercostals

lift and expand the rib cage

sternocleidomastoid

elevates sternum

scalenes

elevate upper ribs

pectoralis major & minor

helps lift ribs

serratus anterior & posterior superior

elevate ribs

muscles of expiration

internal intercostals, serratus posterior inferior, abdominal muscles: rectus abdominus, external obliques, internal obliques, transversus abdominis

internal intercostals

pulls ribs/thoracic cavity down

serratus posterior inferior

pulls lower ribs down

abdominal muscles: rectus abdominus, external obliques, internal obliques, transversus abdominis

together they push abdominal contents up against the diaphragm and pull ribs down, decreasing thoracic volume

lung volume

the amount of air in the lungs at a given point in time

alveolar pressure

the air pressure within the alveoli (tiny air sacks in the lung). this is the pressure that drives air out of the lungs

chest wall shape

the relative configuration of the rib cage wall, abdominal wall, and diaphragm

tidal volume (TV)

the amount of air exchanged in one quiet breath (-500 mL in adults)

inspiratory reserve volume (IRV)

the extra air you can inhale beyond a normal tidal inspiration 2500mL

expiratory reserve volume (ERV)

the extra air you can exhale after a normal tidal expiration 1500mL

residual volume (RV)

air that always remains in the lungs (cannot be exhaled, prevents lung collapse) 1500mL

vital capacity

VC = IRV + TV+ ERV

max voluntary air in and out

functional residual capacity

FRC = ERV + RV

air remaining after normal expiration

inspiratory capacity

IC = TV + IRV

max air inhaled after normal expiration

total lung capacity

TLC = IRV + TV + ERV + RV

maximum lung air possible

alveolar pressure

the air pressure within the alveoli (tiny air sacs in the lungs)

the pressure that actually drives air out of the lungs

directly related to loudness: more pressure = louder speech; less pressure = softer speech

chest wall shape

determines how forces are distributed between the lungs and chest wall

crucial for maintaining a steady, regulated air stream for connected speech rather than a burst of uncontrolled air

quadripeligia

lung volume: severely reduced; paralysis of abdominal and intercostal muscles limits both inhalation and exhalation

alveolar pressure: weaker pressure generation because expiratory muscles can’t contract well

chest wall shape: shape altered because rib cage muscles can’t stabilize expansion

dyspraxia

lung volume: normal

alveolar pressure: not well controlled

chest wall shape: normal structurally, but movement patterns may be uncoordinated

two forms of speech breathing

extended steady utterances

running speech activities

variables influencing respiratory structure and function

body position, body type, age, s3x, ventilation (activity), cognitive-linguistic load, social factors