THE RESPIRATORY SYSTEM Ch 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. atmospherelungsbloodcells 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 = 4600 mL Inspiratory capacity = maximum amount of air someone can inhale following a resting expiration TV + IRV = 3500 mL

AIR CAPACITIES Functional residual capacity = Volume of air still in lungs after a resting expiration ERV + RV Total lung capacity RV + ERV + TV + IRV = 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 CO 2 levels in CSF Strechiness of the lungs Inlfation reflex Emotions Physical activity

ALVEOLI Alveoli are the last stop for O 2 molecules before they are put into the blood and the spot where CO 2 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.