Presentation on theme: "Respiratory System Gas Exchange Introduction What is our atmosphere made of? Nitrogen 78%, Oxygen 21%, Other 1% Why is breathing important? –Exchange."— Presentation transcript:
Respiratory System Gas Exchange
Introduction What is our atmosphere made of? Nitrogen 78%, Oxygen 21%, Other 1% Why is breathing important? –Exchange of O 2 and CO 2 b/t environment and our bodies What is the O 2 used for? –All cells require O 2 for cellular respiration energy Other gasses? –CO 2 + H 2 O –Expelled as waste
General Functions –Intake of oxygen For Cellular Respiration –Exhale carbon dioxide –Preservation of life
Terminology Breathing: to take air into the lungs and let it out again (inhale and exhale). Gas Exchange: the process of diffusion that allows for carbon dioxide to leave the capillaries surrounding the alveoli while facilitating the entrance of oxygen into the capillary. (Carbon dioxide-out: oxygen in)
Cellular Respiration: when cells oxidize organic carbon to obtain energy. This is different from just respiration or the respiratory system. Note: the start product (oxygen) and end product (carbon dioxide) necessitate the need for the respiratory system.
Breathing vs. Respiration (Terminology) Breathing –Intake of O 2 –Exhale CO 2 –Gasses exchanged in alveoli in lungs Respiration –C 6 H 12 O 6 + 6O 2 = 6CO 2 + 6H 2 O –Breakdown of sugar into energy –Takes place in all cells Gas Exchange: –Diffusion allowing for carbon dioxide to leave the capillaries and oxygen to come in. (Carbon dioxide-out: oxygen in)
Respiratory Structures and their Functions Mouth and nostrils –Air enters respiratory system –Allows a larger volume of air to be transferred Nasal cavities –Provide moisture –Filter and trap particles Hair and mucous
Respiratory Structures and their Functions Pharynx –In mouth –connect to the back of the oral and nasal cavities. The pharynx is also connected to the trachea and esophagus –Passage for food and air (digestion and gas exchange –Lined with ciliate epithelial cells to trap fine particles –Contains tonsils and adenoids
Epiglottis –A leaf-like flap of tissue –prevents food from entering the trachea. Respiratory Structures and their Functions
Vocal chords: two elastic ligaments that produce sounds depending on various tensions. Respiratory Structures and their Functions
Adam’s apple –cartilage that protects the larynx.
Respiratory Structures and their Functions Trachea –Windpipe –Takes air into the lungs. –Lined with cilia Mucus Filter extra particles –Cartilage rings Provide support Keep trachea open
Respiratory Structures and Their Function Cilia: small hairs that trap particles. Cilia move upwards to move particles back upwards so that they can be spit out. Trachea Pharynx
Respiratory Structures and their Functions Bronchi –Two branches of the trachea –Contain cartilage –Go to R & L lungs Bronchioles –Smaller branches inside each lung that are less than 1mm in diameter –No cartilage –Rings of muscle – change diameter
Respiratory Structures and their Functions Alveoli –The point of gas exchange –The overall purpose of alveoli is to increase surface area for gas exchange. –Very thin air sacs –Surrounded by capillaries –Site of gas diffusion Concentration gradient –One cell thick –Each lung - ~ 150 million –Film of lipoprotein – prevents alveoli from sticking together
Lungs –Two cone shaped organs –right has 3 lobes –left has 2 lobes shares space with heart –Located in thoracic cavity -base contacts diaphragm and top above the clavicles Respiratory Structures and their Functions
Pleural Membrane –Outer surface of lungs –Inner wall of chest cavity –Reduced friction
Diaphragm –Band of muscle shaped like a dome –Separates thoracic cavity from abdominal cavity –Helps in breathing Respiratory Structures and their Functions
Ribs: bones that protect the thoracic cavity. Respiratory Structures and their Functions
Intercostal muscles –muscles between the ribs that aid in breathing.
Human Gas Exchange System
Section of head and thorax to show respiratory system. left lung (surface) view Right lung (section) 1 Nasal cavity 2 Pharnyx 3 Epiglottis 4 esophagus 5 Cartilage rings 6 Bronchi 7 Lung Diagram Answers 8Heart 9Pleural membranes 10Diaphragm 11Alveoli 12 Pleural membranes 13 Bronchioles 14 Intercostal muscles 15 Ribs 16 Trachea 17 Larynx
Mechanism of Breathing
BREATHING MOVEMENTS Oxygen continuously moves from alveoli into blood Carbon dioxide from blood to alveoli Air in alveoli must, therefore, be continuously replaced with fresh air
INHALATION 1.diaphragm contracts 2.intercostal muscles contract 3.increase in lung volume 4.environmental air pressure is greater than the lung pressure 5.air rushes in to equalize pressure
EXHALATION 1.diaphragm relaxes up 2.intercostal muscles relax 3.decrease in lung volume 4.lung pressure is greater than environmental air pressure 5.air rushes out to equalize pressure
Inhalation and Exhalation
Role of Diaphragm During inhalation –regulates pressure in chest cavity Contract – flattens, moves down Volume increases, pressure decreases Air moves into lungs During exhalation Relaxes – dome shaped, moves up Chest volume decreases, pressure increases Air moves out
Role of the Intercostal Muscles –Intercostal muscles are located between the ribs –Inspiration: Muscles contract, pulls ribs up and out –Expiration: Muscles relax, ribs move down
Diffusion Across Alveoli In LUNGS – –Higher concentration of oxygen than in blood. –Lower concentration of carbon dioxide than in blood.
RESULTS Diffusion Across Alveoli Oxygen moves from the air in the lungs across the alveoli and into the capillary where it becomes attached to hemoglobin. Carbon dioxide moves from the blood across the alveoli and into the air of the lungs.
Alveoli Characteristics that facilitate diffusion: –have thin walls –kept moist –richly supplied with blood vessels –large surface area
REGULATION & CONTROL –Medulla Oblongata -- breathing center controls rate and depth of breathing the medulla is sensitive to CO 2 levels in the blood If CO 2 (carbonic acid) level too high... –medulla tells diaphragm and intercostals to increase activity once CO 2 levels drop into normal range... –medulla stops sending “increase activity” message
REGULATION & CONTROL Chemoreceptors – –If stimulated – Diaphragm begins breathing movements More breathing, lower CO 2 levels Can be controlled –Medulla will take over if CO 2 builds up
QUANTITIES OF AIR normalTIDAL VOLUME – amount air exchanged with each normal breath inhaledINSPIRATORY RESERVE – additional air that can be inhaled over and above the tidal volume exhaledEXPIRATORY RESERVE – extra air that can be forcibly exhaled in excess of the tidal volume
maximumVITAL CAPACITY – the maximum amount of air that can be forcibly exchanged remainsRESIDUAL VOLUME – amount of air that remains in lungs after forceful expiration. QUANTITIES OF AIR
Transport of Gases OXYGEN TRANSPORT –hemoglobin transports about 97% of the oxygen –3% will diffuse into the plasma –the hemoglobin molecule is composed of 4 peptide chains with an iron center –oxygen attaches to hemoglobin to form oxyhemoglobin –oxygen is released in the tissues
Carbon Dioxide in the Blood Approximately –64% of CO 2 – bicarbonate ion in plasma –27% of CO 2 – combines with hemoglobin –9% of CO 2 – is dissolved in plasma
Transport of Gases CARBON DIOXIDE TRANSPORT CO 2 moves away from muscle –CO 2 continually diffuses into the blood plasma. –an enzyme (carbonic anhydrase) in red blood cells converts some CO 2 and water (from plasma) into carbonic acid –carbonic acid breaks into H + and bicarbonate ions (hydrogen carbonate) –the H + combines with hemoglobin helps avoid significant pH change in blood –the bicarbonate ion stays in the plasma
Transport of Gases When this blood reaches lungs: –new O 2 will combine with hemoglobin displacing H + into plasma. –H + recombines with bicarbonate ion producing H 2 O and CO 2 which diffuses into alveoli to be exhaled
Factors Affecting Breathing Rate
1. Exercise When exercise occurs carbon dioxide levels accumulate faster than normal. As a result, your breathing rate and depth increase.
2. Hormones Hormones such adrenaline increases breathing rate
3. High Altitude At higher altitudes there is less oxygen present in the atmosphere. This does not have a great effect on carbon dioxide receptors. Receptors in the arteries will increase the breathing rate.
4. Carbon Monoxide CO acts as a competitive inhibitor in the red blood cell CO attaches to the hemoglobin molecule 200 times stronger (and faster) than O 2 or CO 2 This makes the hemoglobin unavailable for O 2 or CO 2
Holding Your Breath When you hold your breath carbon dioxide levels begin to build. As a result, when breathing is resumed it occurs at a faster rate and with greater depth than normal.
Hyperventilation When you hyperventilate your carbon dioxide levels temporarily decrease. This temporary carbon dioxide decrease would allow you to hold your breath for longer periods of time.
Disorders Bronchitis –Inflammation of bronchioles –Air passages get smaller –Excess mucus –Harder to exhale than inhale –Can lead to asthma and emphysema
Emphysema –Increased resistance to airflow –Over-inflation of the lungs –Alveoli cannot handle pressure Rupture Less SA for gas exchange Lowers O 2 levels
Lung Cancer –Uncontrolled growth of cells –Less surface area for diffusion –Blockages may occur
Tobacco People have smoked tobacco for centuries How is related to this class? Lung cancer –Most common type of death from cancer –50% OF SMOKERS WILL DIE FROM SMOKING RELATED CAUSES
Healthy vs. Unhealthy
The effects of chewing tobacco on a Man.
1.hair loss 2.cataracts 3.wrinkling 4.hearing loss : 6. tooth decay : 7. lung ailments : 9. heart disease : 16. cancer : a)of the lungs b)of the tongue c) of the mouth, salivary glands and pharynx. Other Effects of Smoking