Biology Unit Test - The Respiratory System PDF

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Biology Unit Test - The Respiratory System Alveoli: Air sacs in the lung that provide a very large surface area for gas exchange Asthma: A chronic and potentially life-threatening disorder of the respiratory system in which airways become narrowed, making breathing very difficult Breathing: The process of moving air into and out of the lungs; also known as ventilation Bronchi: Air tubes that connect the trachea to the lungs Bronchioles: Finer tubes that connect the trachea to the lungs Bronchitis: A condition in which the trachea become irritated or infected and produce excess mucus; may become chronic when individuals are exposed to cigarette smoke or other harmful air pollutants Chronic obstructive pulmonary disease (COPD): A serious condition that occurs when chronic bronchitis and emphysema are found together and can lead to respiratory failure Cilia: Short, hair-like structures protruding from a cell that move fluid and other particles over the cell’s surface; sometimes used for movement and food gathering Cystic fibrosis: A fatal genetic disease in which abnormally thick mucus blocks the airways and leads to infection that damages the lung tissue Diabetes: A group of diseases in which high levels of blood glucose result from a problem with insulin secretion, insulin action, or both Diaphragm: A large dome-shaped sheet of muscle that forms the bottom wall of the chest cavity Emphysema: A condition that occurs when the cilia lining the airways are damaged, such as by environmental pollutants, and no longer filter and channel particles Gills: Folds in the body surface of fish that are specialized for gas exchange Homeostasis: The state of internal stability maintained in the body Influenza: A common viral infection of the upper respiratory system spread by airborne droplets and contact with contaminated objects; also called the flu Insulin: A chemical produced by the pancreas and that controls the level of blood glucose Larynx: An organ in the neck that contains vocal cords which vibrate, producing sounds; also called the voice box Lungs: Internal, thin walled sacs with a high surface area for gas exchange; found in reptiles, birds, mammals, and some amphibians Pneumonia: A serious infection of the lungs in which the alveoli fill with fluid, preventing oxygen from reaching the blood; can be caused by a variety of viruses, bacteria, fungi and parasites Respiratory surface: Gas exchange membrane in most multicellular organisms Severe acute respiratory syndrome (SARS): A serious pneumonia-like respiratory disease that is caused by a coronavirus and spread through coughing or sneezing Sinusitis: A condition caused by viruses or bacteria in which the sinuses become swollen and irritated Trachea: Airway held open by c-shaped rings of cartilage; also called the windpipe Tracheal system: A system of tubes that extend through an insect’s body for the purpose of gas exchange Tumours: Group of cancer cells

Structure and Function of Respiratory system Transfer of Gases ● Cellular respiration produces energy to fuel all cells which occurs in mitochondria ● Cells need a constant intake of oxygen and outtake of carbon dioxide ● In animals with lungs, transfer of gases from environment has 3 phases: breathing, transport, and exchange Respiratory Surface ● This is the membrane responsible for gas exchange in multicellular organisms ● It has specific characteristics ○ Very thin, moist, permeable membrane ○ Large surface area for diffusion ○ A diffusion gradient must be maintained to move gases from high to low concentration ● Some animals use entire body surface (ex. Earth worm) Exchange in Aquatic Animals ● Gills are folds in body surface that are specialized for gas exchange ● Enable water to flow so gases can diffuse from water and across respiratory membrane ● Oxygen diffused into capillaries and carbon dioxide out into environment Exchange in Terrestrial Animals ● Most insects have a tracheal system, tubes that run through the body where air enters and leaves ● Larger tubes called trachea branch into small tracheoles which extend to every cell ● Small insects use diffusion, larger insects pump air through rhythmic body movement Lungs ● Used by reptiles, birds, mammals, and some amphibians ● They are interna thin walled sacs with large surface area where oxygen diffuses into the blood and CO2 diffuses out Human Respiratory System ● Structure includes: nose, pharynx, larynx, trachea, and lungs Respiratory System Lining ● Lined with moist epithelial tissue ● The trachea and bronchi are also covered with cilia that are short hair-like structures that move fluid and particles over the cell’s surface Breathing ● Also called ventilation, it is the process of moving air in and out of lungs ● Average rate is 15 breaths per minute, with a total lung capacity of 6L

Diaphragm ● Large dome-shaped muscle that forms the bottom of the chest cavity ● It contracts when you inhale, lung volume increases ● It relaxes when you exhale and lung volume decreases Regulation of Breathing ● Ventilation and gas exchange must be effective ○ Controlled by the medulla oblongata which sends nerve signals to diaphragm and rib muscles to contract and relax ● CO2 dissolves in plasma forming carbonic acid lowering pH, which is then sensed by the brain sending signals to the diaphragm and rib muscles to increase breathing ● Carbon dioxide is exhaled, pH returns to normal and homeostasis is maintained Parts of the Respiratory System Nasal cavity: Air enters through nostrils, filters impurities, warms air. Used for smell, draining sinus and tear ducts, proper speech and pronunciation Pharynx: 3 parts (nasopharynx, orthopharynx, laryngopharynx). Serves in swallowing process Larynx: AKA voice box. Serves in voice production, prevents food from entering respiratory tract along with epiglottis Trachea: AKA windpipe. Used for passage of air and divides into two bronchi (left and right bronchioles) Left bronchus: Enters the wing and divides and subdivides into bronchioles (same as right) Bronchioles: Tiny subdivisions of the bronchi that branch into alveolar ducts and alveoli (air sacs) Left lung: 2 lobes, same function as right lung but has a cardiac notch for the heart Right lung: 3 lobes that transport air into the blood and removes gases out of blood Diaphragm: Large dome-shaped muscle that contracts and moves downward and allows air to enter the body The Respiratory System in Greater Detail UPPER RESPIRATORY TRACT Nose - The purpose of the nasal passage is increased by the presence of numerous thin bones called turbinates f ound in the nasal chambers; the turbinates are covered with the mucus secreting cells, as well and are also well supplied with capillaries. - Air enters through nostrils, filters impurities, warms air, moisturizes air, used for smell, draining sinus and tear ducts, proper speech and phonation. As air enters the nasal passageway it is conditioned in three ways... 1. cleaned  by hairs that remove large particles (snot). 2. moistened  by mucus that is secreted by cells lining the nasal cavity. The cilia in these cells trap dust and bacteria. 3. warmed by capillaries directly below the mucus membrane.

*all serve to protect the delicate lung tissue; note that by breathing through the mouth, all the below advantages are lost* Tongue ● muscle in oral cavity. Pharynx ● Function = passageway for air during respiration, and food during swallowing. ● It is the empty space of the oral cavity. ● It is divided into three sections... 1. Nasopharynx: above the soft palate, takes in air from nose. 2. Orthopharynx: at the back of the mouth, takes in air from mouth. 3. Laryngopharynx: right before larynx. ● Houses the adenoids and tonsils, part of the immune system which fights disease and infection. Glottis ● The opening of the trachea. Epiglottis ● The flap of cartilage that covers the glottis while swallowing, thus protecting the respiratory tract. Larynx ● Also known as the voice box, serves in voice production, stops food from entering respiratory tract along with epiglottis. ● Function = to conduct air from the pharynx to the trachea; also houses the vocal cords. ● Made of cartilage. ● In front of the larynx is the hyoid bone  which is aka the Adam's Apple. Vocal Cords ● Normal breathing = large gap between the cords. ● Prepare to speak = muscles around the larynx contract. ● As exhaled air travels across this narrower space the vocal cords vibrate, producing sound that is shaped into words by the tongue and lips. ● Pitch of sound varies with length of the cords (long cord = low sound, short cord = high sound) ● At puberty the vocal cords of males grow quickly; voice cracks. Esophagus ● tube used in digestion. Trachea ● also known as the windpipe, used for passage of air and divides into two bronchi (left and right bronchus). ● 2.5 cm in diameter, 10-12 cm in length. ● Extends from larynx to top of lungs where it then forks into left and right bronchi. ● Kept from collapsing by surrounding tissues and cartilaginous rings. ● Inside is lined with ciliated goblet cells that produce and secrete mucus.

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The cilia beat upwardly to move any trapped particles and mucus upward.

Left Bronchus: enters the lung and divides and subdivides into bronchioles. Left lung: 2 lobes, same function as right (cardiac notch). Right lung: 3 lobes, transports air (oxygen) into the blood and removes gases (carbon dioxide) out of the blood. Bronchioles: Tiny subdivisions of the bronchi that branch into alveolar ducts and in alveoli (air sacs). Diaphragm: large dome-shaped muscle that contracts, moves downward, and allows air to enter the body. **Ribs, Sternum, and clavicles are bones that protect the lungs and provide support for thoracic cavity. LOWER RESPIRATORY TRACT ● Begins where the trachea branches out into the left and right bronchi Right Lung Superior Middle Inferior ● ● ● ● ●

Left Lung Superior Inferior Cardiac notch

Surrounded by the rib cage, sternum, and spine which offer protection but can be harmful if ribs break, could puncture lung. Fill the thoracic cavity except for the mediastinum, which is the heart and adjoining major blood vessels) The lobes of the lungs are not symmetrical. The left lung is longer and thinner than the right lung because the heart takes up space on the left side (cardiac notch) and the liver bulges up somewhat on the right side. Each lobe is further subdivided into 10 bronchopulmonary segments, which are serviced by individual bronchioles which makes it possible to remove one diseased portion of the lung without shutting down the rest of the lung.

The Pleurae ● Two continuous membranes that line the lungs and the chest cavity ● The inner visceral pleura adheres to and lines the surface of the lungs ● The outer parietal pleura lines the chest cavity ● Between the membranes is a thin film of liquid that acts as a lubricant ● With each breath the visceral pleura slides on the parietal pleura and because of the lubricant no heat due to friction is created. ● The pleura have 3 functions: 1. Acts a lubricant for the lungs to ensure no friction 2. Aid in the mechanics of breathing to make it easier because of no  friction 3. Separates the lungs from the rest of the thoracic organs.

INNER ANATOMY OF THE LUNGS ● Organs made up of bronchi, bronchioles, alveoli, connective and elastic tissue, nerves, and pulmonary capillaries ● The trachea divides into the left and right bronchi leading into the left and right lobes of the lungs. ● The bronchi branch again (22x) into even smaller bronchioles ● The outside walls of the bronchi and larger bronchioles are also supported by cartilaginous rings ● The tiniest bronchioles lead to the alveolar sacs are terminal bronchioles ● The system looks like an upside down tree ● The inner surfaces of the lung are kept moist by mucus secreting cells to facilitate gas exchange The alveoli ● Each lung contains over 350 million alveoli (singular=alveolus) ● Each is 25 um in diameter and 4um thick (micrometers) ● They are the functional units of the lungs and increase the surface area available for gas exchange thus maximizing rate. ● The total surface area of the lungs is 70 to 90 meters squared. 1. Endothelial cells : these cells allow the diffusion of O2 through them to the capillaries and CO2 through them to the lumen of the alveoli. 2. Secretory cells : secrete SURFACTANT which is a liquid (consists of lipoprotein) that helps to keep alveoli inflate by reducing the surface tension created by the moist environment, otherwise each alveolus would collapse onto itself. ● Alveoli also contain macrophages which are white blood cells belonging to the immunes system that ingest and destroy microorganisms and other foreign particles that have gotten by the defense of the nasal cavity and bronchial tree. ● Alveoli are surrounded by pulmonary capillaries that each alveolus is no more than 1um away from a capillary which decreases diffusion distance thus maximizing rate of gas exchange. ● The entire arrangement of bronchioles and alveoli are kept in position by elastic, connective tissue. **There is a high oxygen concentration inside the capillaries, compared to a low pressure inside the tissue cells. The carbon dioxide level inside the cells of the tissues is high, while the carbon dioxide level is low inside the capillary. Carbon dioxides diffuses out and the oxygen diffuses into the cells.**

The Mechanics of Breathing/Ventilation Inhalation/inspiration 1. The external intercostal muscles contract (pulling ribs closer together). The diaphragm contracts and flattens (moves downward), and the abdominal muscles relax 2. Ribs move up and out 3. Volume of thoracic cavity increases 4. Internal air pressure decreases 5. Air moves in to equalize the pressure imbalance Exhalation/Expiration 1. External intercostal muscles and diaphragm relax, the internal intercostal muscles and abdominal muscles contract 2. Ribs move down and in 3. Volume of thoracic cavity increases 4. Air moves out of lungs to equalize the pressure imbalance ●

This is during normal breathing. During forced expiration the internal intercostal muscles contract reducing the thoracic cavity size even more. The internal intercostal muscles run at right angles to the external intercostal muscles

Mechanics of Breathing Lungs: breathing takes place as air enters and leaves Thoracic cavity: Closed environment bounded along the right and left sides by the ribs and intercostal muscles Intercostal muscles: Receive nerve impulses by medulla oblongata when CO2 is sensed in blood Diaphragm: Dome-shaped muscle that contracts, moves downward, and allows air to enter the lungs by expanding thoracic cavity. Lungs are attached to wall by the parietal pleura membrane and therefore expand Trachea: Windpipe of passageway of air Inhaled air: Flow of air inward, known as inhalation Exhaled air Gas exchange ● Arteries lead away from the heart, carrying oxygenated blood BUT the only exception is the pulmonary artery ● Veins carry blood towards the heart, carrying deoxygenated blood with the exception of the pulmonary vein

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Air is inhaled from trachea Pulmonary artery: brings blood from the heart to alveoli (deoxygenated blood, high [CO2], low [O2]) Pulmonary vein: venules with oxygenated blood unite together to form pulmonary vein which leads to the heart (high [O2], low [CO2]) Arterioles: branches of pulmonary artery Alveolus: contain thin membrane that allow gas exchange to occur between the lungs and bloodstream Capillaries: sub-branches of arterioles that contain blood with CO2. The location of gas exchange Venules: CO2 from capillaries diffuses into alveoli and is exhaled; oxygen is diffused into capillaries leading to venuoles which carry oxygenated blood into the heart

Spirograph: The Amounts of Air in the Lungs ● The events of breathing can be described by subdividing the amount of air in the lungs into 4 volumes and 4 capacities Definition Tidal Volume

The volume of air inhaled or exhaled during ordinary breathing at rest

Inspiratory Reserve Volume

The volume of air taken in beyond the TV when the deepest possible breath is taken

Expiratory Reserve Volume

The volume of air that can be forcibly exhaled after a normal TV is exhaled

Residual Volume

The volume of air remaining in the lungs after a forceful expiration

Inspiratory capacity

The amount of air that can be inhaled, Beginning from a normal exhalation and then filling the lungs to their maximal amount IC = TV + IRV

Functional Residual Capacity

The amount of air that remains in the lungs at the end of normal expiration FRC = ERV + RV

Vital Capacity

The maximal amount of air that a person can expel from the lungs after the lungs have been filled to their maximum extent VC = IRV + TV + ERV

Total lung capacity

The maximum volume of air that can be held in the lungs at any given time TLC = VC + RV

Common Disorders of the Respiratory System ● Regular exercise results in the healthiest respiratory systems. The structure and function of the respiratory system can be altered by disease, exposure to viruses, or environmental pollutants ● The common cold is caused by viruses passing through the protective lining of the nose and throat ○ Can be accompanied by sinusitis (sinuses become swollen, irritated and infected); air spaces around the nose and eyes ● Influenza is a viral disease that affects the upper respiratory system ○ Can lead to pneumonia (infection of the lungs), where the alveoli fill with fluid (prevents oxygen from reaching blood) Asthma ● Chronic condition where airways become narrow. ● Difficult breathing. ● Caused by pollutants, smoking, infections, drugs. ● No real cure; bronchodilator  (in a puffer) can relax muscles around the bronchi and bronchioles to alleviate symptoms. Bronchitis ● Infections of the bronchioles; excess mucus is produced ● Coughing and difficulty breathing. ● Can be chronic is there is exposure to cigarette smoke ● Heart must work harder to get oxygen to the body. Emphysema ● Damage to cilia lining the lungs; they can no longer filter and channel particles that are lining the bronchioles. ● Less air reaches the alveoli for gas exchange with the blood. ● Air pressure builds the lungs appear inflated, walls of the alveoli become deprived of oxygen. ● Caused by smoking and long time exposure to chemicals. Chronic Obstructive Pulmonary Disease (COPD) ● Chronic bronchitis and emphysema together. ● You might need extra oxygen (canister) if suffering. ● Bronchodilators can be used. ● This condition can lead to respiratory failure. Cystic Fibrosis ● fatal genetic disease where mucus blocks the airways. ● Mucus hots bacteria, leading to lung infections. ● Daily physical therapy is needed to ease the flow of air. ● No cure. Severe Acute Respiratory Syndrome (SARS) ● Pneumonia-like disease caused by the coronavirus.

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Difficulty breathing. Hospitalization or death may follow.

Lung Cancer ● Cells reproduce abnormally in the lungs; forming tumours. ● Symptoms: lung infections, chronic coughing, difficulty breathing. ● One type can be treated with surgery. ● The other type is treated with drugs or radiation. ● 85% of lung cancer is caused by smoking. Technologies used to Treat and Diagnose Respiratory Disorders Respirometer ● Used to measure a patient's breathing movements and lung capacity. ● Samples of blood and mucus are observed so that the presence of abnormalities can be observed. Endoscope/Bronchoscope ● Can remove obstructions in the nasal passages. ● If it appears to be in the trachea or lungs, a bronchoscope may be inserted through the nose or throat. Imaging Technologies ● X-ray, CT Scan, MRI: can reveal the size/shape of airways and tumours. Surgery ● This might be a decision influenced by info. received from imaging technologies. ● Lasers can be used in surgery to destroy obstructions. Fluorescent Dyes + Two-photon Imaging Microscope ● Researchers can investigate/examine the molecular ...