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.