The Respiratory System

Respiration Respiration is the interchange of gases between an organism and the medium in which it lives. Internal respiration is the exchange of gases between the bloodstream and nearby cells. External respiration is the exchange of gases between the lungs and bloodstream.

Purpose of the Respiratory System To provide a constant supply of oxygen to keep your body cells functioning To remove carbon dioxide from the body cells

Internal Respiration Exchange of O2 and CO2 between the Capillary and the Body Cell

Organs of the Respiratory System Trachea Bronchus (bronchi) Bronchioles Alveoli Pleura Diaphragm Nose / mouth Nasal cavity Pharynx Epiglottis Larynx Trachea Lungs

Organs of Respiration Mouth & Nose Nasal Cavity Brings air into the body Nasal hairs in nostrils trap dust Nasal Cavity Warms & moistens air Glands that produce sticky mucus line the nasal cavity traps dust, pollen, and other materials that were not trapped by nasal hairs .

Cont… Pharynx Tube-like passageway used by food, liquid, and air . At the lower end of the pharynx is a flap of tissue called the epiglottis(a thin piece of tissue behind the tongue that prevents food or drink form entering the lungs) . Larynx “Voice box” The airway to which two pairs of horizontal folds of tissue, called vocal cords, are attached .

Cont… Trachea Air-conducting tube Connects the larynx with the bronchi Lined with mucous membranes and cilia Contains strong cartilage rings cartilage the strong white tissue that is important in support and especially in joints prevent the bones rubbing each other

Cont… Bronchi Bronchioles Two short tubes that branch off the lower end of the trachea Carry air into the lungs. Singular – bronchus Bronchioles Tiny branches of air tubes in the lungs Connect bronchi to alveoli.

Cont… Alveoli Tiny, thin-walled, grapelike clusters at the end of each bronchiole Surrounded by capillaries Where carbon dioxide and oxygen exchange take place Singular – alveolus Pleura Membrane lining the lungs and chest cavity

Cont…. Diaphragm Muscle wall between the chest and the abdomen that the body uses for breathing

Block Diagram of Air Pathway

Lung Volumes and Capacities

Lung Volumes and Capacities Important volumes to consider are shown in Figure. They are for a standard 70-kg male breathing at rest. Tidal Volume (TV) 500 mL, is the depth of breathing or the volume of gas inspired or expired during each respiratory cycle. Inspiratory Reserve Volume (IRV) 3600 m L, is the maximal amount of gas that can be inspired from the end-inspiratory position (extra inspiration from the high peak tidal volume). Expirarory Reserve Volume (ERV) 1200 mL, is the maximal amount of gas chat can be expired from end-expiratory level (extra expiration from the low peak tidal volume). Residual Volume (RV) 1200 mL, is the amount of gas remaining in the lungs at the end of maximal expiration (amount that cannot be squeezed out of the lung). Even a collapsed lung contains 500 to 600 mL.

Lung Volumes and Capacities Important capacities (addition of various lungs volumes) to consider are also shown in the figure. Total Lung Capacity (TLC) 600 mL, is the amount of gas contained in the lungs at the end of maximal inspiration and is the sum of inspiratory capacity (IC) and functional residual capacity (FRC). Vital Capacity (VC) 4800 mL, is the maximal amount of gas that can be expelled from the lungs by forceful effort from maximal inspiration. Inspiratory Capacity (IC) 3600 mL, is the maximal amount of gas that can be inspired from the resting expiratory level and is the sum of TV and IRV. Functional Residual Capacity (FRC) 2400 mL, is the amount of gas remaining in the lungs at the resting expiratory level (end-expiratory position is used as a base because it varies less than the end-inspiratory state). It is the sum of ERV and RV.

Relationship to digestive system Cellular respiration requires glucose and oxygen to release energy to the body Oxygen is provided by the respiratory system Glucose is provided by the digestive system (glucose is made during photosynthesis)