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The Respiratory system • Why do we need a respiratory system? To remove CO2 (carbon dioxide) from body. To provide O2 for our cells to carry out cellular respiration C6H12O6 + 6O2 6H2O + 6CO2 +38 ATP + Heat The Respiratory system Oxygen/carbon dioxide exchange: • Air entering the lungs is 21% O2; leaving the lungs is 14% O2 • Air entering the lungs is 0.2% CO2; leaving the lungs is 5.6% CO2 Structures of the Respiratory system When you breathe in, air passes over tissue in the nasal cavity which functions to: – They circulate the air warming – hydrating – & Cleansing it. Structures of the Respiratory system Lined with: • Nasal Mucosa- is epithelial tissue- lines nasal cavity – Has mucous glands and cilia – Nasal passage has irregular shape, so air flow changes direction a lot and particles hit walls of passage and stick to the mucous. – Cilia moves particles to the nasopharynx, which drains into the back of mouth. You swallow about 1 pint of mucous a day. Infection causes more mucous to be produced. Structures of the Respiratory system • Nasal Mucosa- continued – Moist mucous lining also hydrates so lung tissue does not dry out. – Vascular tissue (blood vessels)much is in nasal region to warm incoming air. – Mouth breathing- dries air passages and doesn’t filter air. Membranes then swell and block off, causing more susceptibility to infection. OVERVIEW OF THE RESPIRATORY SYSTEM: FUNCTION: REVIEW: What is the equation for cellular respiration? Explain the oxygen/ carbon dioxide exchange: Histology of the nasal passages: When air enters your nasal cavity three things occur before it enters the lungs: (This is accomplished by the tissue that lines the upper respiratory tract) 1. 2. 3. The tissue that lines the nasal cavity is: Characteristics: function of cavities: function of mucus: function of cilia: function of vessels: Disadvantage of breathing through the mouth? Structures of the Respiratory system Bronchi • – – – – Primary- are two (left and right) As they enter the lungs they branch to form secondary and tertiary bronchi. As they get smaller = bronchioles Same basic structure as trachea, but has less cartilage as they get smaller (bronchioles have none) Structures of the Respiratory system Lungs- elastic, spongy organs made of several lobes. • – – – Enclosed in a sacpulmonary pleura. Lining of the chest cavity is parietal pleura Space between the 2 pleura is pleural cavityfilled with fluid to reduce friction of constant lung movement. (pulmonary) Structures of the Respiratory system • Alveoli- tiny air sacs at the ends of the smallest bronchioles – Millions of them; they resemble bunches of grapes. – Light and spongy; because lungs are mostly air. – Walls made up of a single layer of squamous epithelial cells.- are very thin; much thinner than tissue paper. Structures of the Respiratory system Alveoli- • – – – – External surface is covered with a “cobweb” of pulmonary capillaries, their walls are also only 1 cell thick. The air in the alveoli and the blood in the capillaries is separated by a very thin “double wall”, only 2 cells thick. Blood passes on one side (capillaries) and air on the other (alveoli). Gases pass between the 2 by simple diffusion. Total gas exchange surface area= area of a racquetball court! Structures of the Respiratory system Alveoli- • – – – Macrophages wander around alveoli to pick up bacteria and particles. Alveoli also contain some cuboidal cells that produce a surfactant. It lowers the surface tension of the water droplets in the alveoli and allows them to spread out, so they won’t collapse between each breath. Premature babies don’t have this surfactant and can go into respiratory failure unless put on a life support system. ESSENTIAL STRUCTURES OF THE RESPIRATORY SYSTEM 1. Bronchi- same basic structure as trachea but they do two things: smaller bronchi are called: 2. Lungs Protected by linings: 2. • Pulmonary pleura: • Parietal pleura: • Pleural cavity: Alveoli: characteristicsExplain how their structure influences function- Protection: • Macrophages: • Surfactant: