Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Respiratory System Respiratory Function • What do cells need to carry out their vital functions? • Oxygen! • As cells use oxygen they give off carbon dioxide as a waste product. • The respiratory system organs oversee the gas exchanges that occur between the blood and the external environment. • • • • • • Respiratory Organs Nose Pharynx Larynx Trachea Bronchi All serve as conducting passageways that allow air to be purified, humidified, and warmed as the reach the lungs • The lungs contain tiny air sacs called alveoli where gas exchanges with the blood occur. Nose • Also called nasal cavity • Interior is lined with the respiratory mucosa and a network of thin walled veins that warm the air as it flows past. • The sticky mucus also traps incoming bacteria and debris and moistens the air. • The ciliated cells of the mucosa move contaminated mucus toward the throat for digestion. Nose • Conchae- located on lateral walls of nose – Increase the surface area exposed to air • The nasal cavity is separated from the oral cavity by the hard and soft palates. Pharynx • • • • Aka the throat Muscular passageway Food and air both pass through the pharynx. Food is directed to the esophagus when the epiglottis closes. • Air is allowed through the epiglottis into the larynx. Larynx • Voicebox • Formed by 8 rigid hyaline cartilages and the spoon shaped flap of elastic cartilage called the epiglottis. • Thyroid cartilage- largest- Adam’s apple • When we swallow the larynx is pulled upward and epiglottis tips, forming a lid over the larynx. • Place your hand midway on the anterior surface of your neck. • Swallow. • Can you feel the larynx rising as you swallow? Trachea and Bronchi • The trachea is also called the windpipe. • It is lined with ciliated mucosa that beat continuously in a direction opposite to the incoming air. • The right and left bronchi are formed by the division of the trachea and enter the medial depression of the lung. Lungs • The surface of each lung is covered with visceral serosa called the pulmonary or visceral pleura. • The thoracic cavity is lined with the parietal pleura • These two layers cling tightly to one another while still allowing smooth sliding of the lungs across the thorax during breathing. Lungs • After the bronchi enter the lungs they subdivide into smaller and smaller branches until they become bronchioles. • The terminal bronchioles lead to the respiratory zone structures • Respiratory zone structures eventually terminate in the alveoli, or air sacs that serve as the site of air exchange. Respiratory Zone Respiratory Membrane • The external surfaces of the alveoli are covered in a cobweb of pulmonary capillaries. • Together these two structures make up the respiratory membrane (air-blood barrier) Respiratory Membrane Tuesday 5/7/13 • Do Now: • What is tidal lung volume? • What is vital lung capacity? Respiratory Physiology • There are 4 distinct events collectively called respiration. 1. Pulmonary Ventilation (breathing)- air must move in and out of the lungs so that the gases in the air sacs of the lungs are continuously changed and refreshed. Respiratory Physiology 2. External Respiration – gas exchange between the pulmonary blood and alveoli must take place Respiratory Physiology 3. Respiratory Gas Exchange – oxygen and carbon dioxide must be transported to and from the lungs and tissue cells of the body via the blood stream. Respiratory Physiology 4. Internal Gas Exchange – gas exchange at the systemic capillaries between the blood and tissue cells. Mechanism of Breathing • Volume changes lead to pressure changes which lead to the flow of gases to equalize the pressure. • Inspiration: air flowing into the lungs • Expiration: air leaving the lungs. Mechanism of Breathing • Atmospheric Pressure- pressure outside the body • Intrapulmonary Pressure – Pressure inside the lungs • Intrapleural Pressure – Pressure within the Pleural space. (must always be less than the atmospheric pressure or else the lungs will collapse) Gas Exchange • always a higher concentration of oxygen in the alveoli than in the blood • oxygen moves from the alveoli, through the respiratory membrane into the more oxygen poor blood of the pulmonary capillaries. Gas Exchange • As tissue cells remove oxygen from the blood, they release carbon dioxide into the blood. • Because the concentration of carbon dioxide is much higher in the pulmonary capillaries than in the alveolar air, it will move from the blood into the alveoli and be flushed out of the lung on expiration. Wednesday 5/8/13 • Do Now: • Describe pulmonary ventilation Objectives • Control of Respiration • Factors that influence the respiratory system: – Physical factors – Volition (conscious control) – Emotional Factors – Chemical Factors Neural Regulation: Setting the Basic Rhythm • Phrenic and intercostal nerves transmit impulses to control the activity of respiratory muscles, diaphragm, and external intercostals. • Medulla- sets basic rhythm for breathing. • Pons- smooth out the basic rhythm of inspiration and expiration set by the medulla. • Impulses going back and forth between the pons and medulla maintain a rate of 12-15 respirations/minute. – eupnea Neural Regulation: Setting the Basic Rhythm • Bronchioles and alveoli have stretch receptors that respond to extreme over inflation. • Hyperpnea- more impulses sent to respiratory muscles Physical Factors • Talking, coughing, exercising • Increased body temperature causes an increase in the rate of breathing. Volition (Conscious Control) • During singing and swallowing breath control is important. • Hold our breath to swim underwater. • Voluntary control is limited • Respiratory system will ignore messages from the cortex(wishes) if pH is falling or oxygen supply in blood is getting low. Volition (Conscious Control) • Try to run at your fastest speed and then hold your breath- it is impossible Emotional Factors • Watching a horror movie and holding your breath • Watched a horror movie and got so scared that you start panting Chemical Factors • ***most important*** levels of carbon dioxide and oxygen in the blood • Increased carbon dioxide or decreased blood pH are the most important stimuli leading to an increase in respiratory rate. Chemical Factors • Changes in carbon dioxide concentrations in the blood act directly on the medulla centers. • Changes in oxygen concentration detected by aorta and carotid arteries • Although oxygen is important- it is the body’s need to rid itself of carbon dioxide Thursday 5/9/13 • Do Now: How can emotional factors affect respiratory rate and depth? Objectives • Respiratory Disorders –Chronic Obstructive Pulmonary Disease (COPD) • Emphysema • Chronic bronchitis • Lung cancer Respiratory Disorders • Respiratory system is vulnerable to infections because it is open to airborne pathogens. • COPD- Chronic Obstructive Pulmonary Disease • Lung cancer • Living proof of cigarette smoking’s devastating effects on the body. COPD • Examples: chronic bronchitis and emphysema • Major cause of death in the United States • Common features (emphysema and chronic bronchitis) – 1. patients almost always have a history of smoking – 2. dyspnea- difficulty breathing- occurs and becomes more progressively severe – 3. coughing and frequent pulmonary infections – 4. hypoxic, retain carbon dioxide, and have respiratory acidosis Emphysema • Alveoli enlarge- walls of adjacent chambers break through- chronic inflammation promotes fibrosis of the lungs. • Lungs become less elastic • Airways collapse Emphysema • These patients use a lot of energy to exhale and are always exhausted. • Oxygen exchange is surprisingly efficient because air is trapped in the lungs. • People who suffer from the disease – “pink puffers” - overinflation of the lungs leads to an expanded barrel chest. Chronic Bronchitis • Mucosa of the lower respiratory passages becomes severely inflamed and produces excessive amounts of mucus. • Mucus pulls and impairs ventilation and gas exchange. • “Blue bloaters”- hypoxia and carbon dioxide retention occur early in the disease and cyanosis is common