Respiratory system By: Ellie Conzatti, Kelsey Betteridge, and Michele Short
Functions • Cellular Respiration (obtaining oxygen and removing carbon dioxide) • Removing particles from the air • Transport air to and from lungs • Control temperature and moisture content of air • Produce vocal sounds • Help regulate blood pH and sense of smell
Structures of the Respiratory System • Nose • Nasal cavity • Hard palate • Nostril • Oral cavity • Larynx • Bronchus • Right & left lung • Soft palate • Pharynx • Epiglottis • Esophagus • Trachea
Organs of the Respiratory System Upper Respiratory Tract • Nose, Nasal cavity, paranasal sinuses, and pharynx Lower Respiratory Tract • Larynx, trachea, bronchial tree, and lungs
Nose • Bone and cartilage support the nose • There are two nostrils which air can enter and leave the nasal cavity • Hairs within the nostrils prevent large particles from entering
Nasal Cavity • Hollow space behind the nose • The nasal septum divides the right and left portions of the nasal cavity • Nasal concha are bones that curl away from the lateral walls of the nasal cavity on each side forming passageways within the cavity • Mucous membrane has… * pseudo stratified ciliated epithelium * mucus-secreting goblet cells * network of blood vessels * mucus lining * sticky mucus
Paranasal sinuses • Hollow spaces in certain skull bones which are located in the: • Maxillary • Frontal • Ethmoid • Sphenoid Bones • Reduces weight of skull • Serves as resonant chambers • Affects the sound of the voice
Pharynx • Chamber behind nasal cavity, oral cavity, and larynx • Passageway for air moving from nasal cavity to larynx • Food moves from oral cavity to esophagus
Larynx • Passageway for air and prevents foreign objects from entering trachea • The glotis is the opening between the vocal cords that closes during swallowing. During breathing , they are relaxed and it looks like a triangular slit. • A framework of muscles and cartilages compose the larynx • Thyroid (“Adam’s apple”) • Cricoid • Epiglottic cartilages
Larynx (cont.) • Contains the epiglottis, a flap-like structure that closes downward to cover the opening into the larynx during swallowing. This prevents food and liquids from entering the air passages.
Trachea (Windpipe) • Flexible tube that connects the larynx with the bronchial tree by splitting into left and right bronchi. • Passageway for air • Air is being filtered by a ciliated mucous membrane covering the wall. Filtered air is moved upward into the pharynx where the mucus is swallowed. • Consists of about 20 C-shaped hyaline cartilage pieces which are filled with smooth muscle and connective tissue between the ends.
Bronchial Tree • Branched tubes that lead from the trachea to the lungs • Has a mucous lining that continues to filter incoming air • Divides into the right and left primary bronchi and then each one further divides into secondary bronchi. • Bronchioles are among these smaller tubes and finally break into small tubes called alveolar ducts, which lead to alveolar sacs. Alveolar sacs are surrounded by alveoli.
Bronchial Tree (cont.) The alveoli’s large surface area of epithelial cells allow gases to be exchanged. Oxygen enters nearby capillaries and carbon dioxide enters the alveoli from the blood through these walls.
Lungs • Soft, cone-shaped organs that occupy a large portion of the thoracic cavity • Contains air passages, alveoli, blood vessels, connective tissues, lymphatic vessels, and nerves of the lower respiratory tract. • The visceral pleura, which is a serous membrane, attaches to each lung surface. It folds back to become the parietal pleura, a part of the mediastinum, a layer of the inner wall of the thoracic cavity. The potential space between these two layers is the pleural cavity. • The right lung is larger than the left • The right is divided into three parts • The left is divided into two parts
Breathing Mechanism • The movement of air coming from the outside of the body and going into and out the bronchial tree and alveoli • Inspiration- inhaling • Expiration- exhaling
Inspiration • When the pressure in the lungs and alveoli decreases, the pressure pushes outside the air into the pathways • This is normal inspiration. While the external intercostal muscles between the ribs are contracting, this is what raises the ribs and the sternum, causing the thoracic cavity to enlarge • When a person needs to take a bigger and deeper breath, the diaphragm and external intercostal muscles contracts even more to help with the breathing
Expiration • To get back to the normal shape, the abdominal organs bounce back pushing the diaphragm up again • When a person needs to exhale more than normal, the posterior internal intercostal muscles are contracting • This causes the ribs and sternum down and in which increases the pressure inside the lungs
Respiratory Center • Respiratory muscles are voluntary whereas normal breathing is involuntary • The respiratory center controls both inspiration and expiration • It is a group of neurons • The neurons are scattered throughout the medulla oblongata and the pons • The dorsal respiratory group controls the rhythm of inspiration • This impulses the diaphragm and the other inspiratory to contract • It begins weak, strengthens for two seconds and decreases again • The muscles that contract, increase the air that enters the lungs • The ventral respiratory group is quiet when the breathing is normal, but when more force is needed, this impulses an increase in the inspiratory movement.
Respiratory Membrane • The aveolus consists of inner lining of simple squamous epithelium and capillaries as well • Thin basement membranes separate these layers and in the spaces between, the elastic and collagenous fibers support the alveolar wall • Composed of the alveolar wall and the capillary wall through which air exchanges gases
Air and Blood Exchange Gases Across Alveoli To Capillaries • Diffusion occurs from areas of higher pressure to areas of lower pressure. • Ordinary air consists of 78% nitrogen, 21% oxygen, and .04% carbon dioxide. • The pressure each gas gives is the partial pressure. • Gas concentration is proportional to its partial pressure • PCO2 in capillaries is 45 mm Hg while in alveolar air it is 40 mm Hg • PO2 in blood is 40 mm Hg while in alveolar air it is 104 mm Hg
Gas Transport By Blood Oxygen • Oxygen binds to an iron protein, called hemoglobin, to form oxyhemoglobin. • Since oxygen and hemoglobin molecules are unstable, oxyhemoglobin releases oxygen into nearby cells. • More oxygen is released when: • Po2decreases • Carbon Dioxide concentration increases • Blood becomes increasingly acidic • Blood temperature increases • Hypoxia is a deficiency of oxygen reaching the cells.
Gas Transport By Blood • As carbon dioxide dissolved in plasma • If the partial pressure of the carbon dioxide is higher in the tissues, more will dissolve in the plasma. • As a compound bonded to hemoglobin • Carbon dioxide binds to the protein part of hemoglobin, not the iron, and therefore does not compete with the binding of oxygen. This bond creates carbaminohemoglobin. • In the form of a bicarbonate ion • Carbon dioxide and water react to create carbonic acid. • Carbonic anhydrase is an enzyme in red blood cells that speeds up the reaction. • Carbonic acid splits to become a hydrogen ion and bicarbonate ion. Carbon Dioxide is transported to the lungs in 1 of 3 ways: As carbon dioxide dissolved in plasma. As a compound bonded to hemoglobin. In the form of a bicarbonate ion
Factors that Affect Breathing • Central chemoreceptors sense changes in the cerebrospinal fluid of carbon dioxide and hydrogen ions • When more carbon dioxide is being exhaled, the blood and CSF causes the breathing rate to decrease • Hyperventilation is when someone is breathing really deep and rapidly • This causes an increase in breath
Diseases • Laryngitis • Hoarsness or lack of voice • The mucus membrane of the larynx becomes inflamed and swollen due to infection or an irritation from inhaled vapors • Prevents the vocal chords from vibrating freely
Emphysema • Progressive and pregenerative disease that destroys alveolar walls • As a result, surface area decreases and the volume of gases exchanged through the membrane reduces • Expiration becomes more difficult • Caused by repeated exposure to respiratory irritants like tobacco and pollution
Lung Cancer • Division of cells that take the nutrients and oxygen out of normal cells • It can sometimes be developed from other cancer cells in different parts of the body • Cancer cells form tumors that block air passages and decrease the exchange of gas
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