THE RESPIRATORY SYSTEMCh 16 Notes
IDENTIFY THE FUNCTIONS OF THE RESPIRATORY SYSTEM.
• Obtaining oxygen and removing carbon dioxide.• Cellular Respiration: carbs + O2 -> CO2 + H2O + 36
ATP
• Filters incoming air; control water content and temperature of incoming air; produce vocal sounds, regulate blood pH, aid in the sense of smell.
WHAT IS RESPIRATION?
• Gas exchange between the atmosphere and cells.
atmosphere
lungs
blood
cells
blood
lungs
LOCATE THE ORGANS OF THE RESPIRATORY SYSTEM.
• Upper respiratory – nose, nasal cavity, paranasal sinuses, and pharynx.
• Lower respiratory – larynx, trachea, bronchial tree, and lungs.
DESCRIBE THE FUNCTION OF EACH ORGAN.
• Nose – air entry/exit; hairs filter particles
• Nasal septum – separates left from right
• Nasal conchae – bones that curl on wall of nasal cavity; support mucous membrane – mucous-secreting goblet cells • Traps dust and particles• Warms air to body temp as it enters
MOVEMENT OF AIR FROM ATMOSPHERE TO BLOOD
• Nose/Moutth – over the nasal conchae
• Pharynx
• Larynx – through the glottis
• Trachea
• Bronchial tree
• Primary bronchi
• Lobar bronchi
• Bronchioles
• Alveolar ducts
• Alveolar sacs
• Alveoli
BREATHING MECHANISM
• Atmospheric pressure outside vs inside determines air movement
• Atmospheric pressure > air pressure in lungs = inspiration
• Atmospheric pressure < air pressure in lungs = expiration
INSPIRATION
• Diaphragm moves downward.
• External intercostal muscles may contract, raising the ribs and sternum.
• Thoracic cavity enlarges.
• Pressure on lungs is relieved.
• Air rushes inward.
• For deeper breaths, add in the pectoralis minor and sternocleidomastiod muscles.
• Inspiration Video
EXPIRATION
• Tissue experiences elastic recoil.
• Everything goes back to its original shape, restoring the original air pressure in the lungs, which pushes air out.
• Normal resting expiration is a passive process.
• Exhaling more than normal – internal intercostal muscles contract pulling ribs and sternum inward and downward. Abdominal wall muscles can also pull abdomen inward, pushing diaphragm upward.
AIR VOLUMES
• Respiratory cycle = 1 inspiration + 1 expiration
• Spirometry – Test that measures air volumes
• Tidal volume = amount of air that enters or leaves in one respiratory cycle
• Resting tidal volume (normal) = about 500 mL
AIR VOLUMES
• Inspiratory Reserve Volume = extra amount of air taken in during forced inspiration. (max = about 3,000 mL)
• Expiratory Reserve Volume = extra amount of air breathed out during forced expiration (max = about 1,100 mL)
• Residual Volume = amount of air left in lungs after a forced expiration.
AIR CAPACITIES
• Vital capacity = maximum amount of air someone can exhale after taking the deepest breath possible• TV + IRV + ERV• 500 + 3000 + 1100 = 4600 mL
• Inspiratory capacity = maximum amount of air someone can inhale following a resting expiration• TV + IRV• 500 + 3000 = 3500 mL
AIR CAPACITIES
• Functional residual capacity = Volume of air still in lungs after a resting expiration• ERV + RV• 1100 + 1200
• Total lung capacity• RV + ERV + TV + IRV• 1200 + 1100 + 500 + 3000 = 5800 mL
RESPIRATORY VOLUMES AND CAPACITIES
CONTROL OF BREATHING
• Respiratory areas - Groups of neurons in the brainstem control breathing
• Medullary Respiratory Center• Ventral respiratory group –
controls basic rhythm• Dorsal respiratory goup –
stimulates inspiratory muscles; processes sensory information about respiratory system
• Pontine Respiratory Group• May contribute by limiting
inspiration
FACTORS AFFECTING BREATHING
• Respiratory areas affect breathing rate and depth.
• Factors• Chemicals
• CO2 levels in CSF• Strechiness of the lungs
• Inlfation reflex• Emotions• Physical activity
ALVEOLI
• Alveoli are the last stop for O2 molecules before they are put into the blood and the spot where CO2 enters back into the respiratory system for exhalation.• Video
• Walls made of simple squamous epithelium.
• Covered by walls of capillaries – which also have simple squamous epithelium.
• Respiratory membrane – space inbetween where gases are exchanged.
GAS EXCHANGE
• In the alveoli, the partial pressure of oxygen is greater than that of the blood.
• The partial pressure of carbon dioxide is lower than that of the blood.
• So...oxygen moves from alveloli to blood and carbon dioxide moves from blood to alveoli.
GAS EXCHANGE
OXYGEN TRANSPORT
• Blood carries oxygen from the lungs to the cells and carries carbon dioxide back.
• It’s transported by hemoglobin in red blood cells.
• Hypoxia – a deficiency of oxygen in cells
• Carbon dioxide is transported dissolved in plasma, bonding to hemoglobin, or as a bicarbonate ion.
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