Respiratory System cells need oxygen to release energy

Respiratory System

�cells need oxygen to release energy from food �without energy, cells cannot carry out their main functions �respiration ensures that the body gets the energy needed to function

Respiration involves: �External respiration (breathing) � inhaling oxygen from the air and exhaling to expel carbon dioxide from the lungs � O 2 is taken up by capillaries of lung alveoli and CO 2 is released from blood �Internal respiration � metabolic process O 2 is released to tissues /cells and CO 2 is transferred to the blood �Cellular respiration � O 2 is used by cells for producing energy ATP (adenosine triphosphate)

Image from: http: //web. carteret. edu/keoughp/LFreshwater/CPAP/Circulatory/circulatory_class_notes_files/image 012. jpg

Respiratory System Structures

nasal cavity pharynx epiglottis larynx trachea lung bronchus bronchiole diaphragm

Nasal Cavity �separated from the mouth cavity by a bony platform called the hard palate �nasal cavity warms, moistens, and cleans the air before it hits the lungs �many blood vessels help warm the air (surface area is important!) �epithelial cells provide moisture and mucus Image from: http: //www. medart. plus. com/Artwork_GIFs/nasalcav. GIF

Pharynx �forms a tube common to respiratory and digestive systems �extends from back of nasal cavity to the larynx (voice box) �nasopharynx (top part) � have ciliated epithelial cells that trap fine particles � contains the tonsils and adenoids (lymphoid tissue) �oropharynx and laryngopharynx (bottom part) � behind the mouth – passage for food and air � epithelial cells here are tough because of the wear and tear from food passage �divides into two tubes: esophagus (food) and larynx (air)

Image from: http: //www. cedars-sinai. edu/Patients/Programs-and-Services/Head-and-Neck-Cancer-Center/Treatment/Images/pharynx_openmouth_web-80182. jpg

uvula : What is it for? __________________ Image from: http: //mentalfloss. com/article/30806/what-does-dangly-thing-back-your-throat-do

Larynx �box-like structure at the opening of the airway �formed by cartilage structures to prevent collapse �thyroid cartilage is largest – makes the Adam’s apple �leaf-like flap is called the epiglottis �prevents food from entering airway Images from: http: //www. cedars-sinai. edu/Patients/Programs-and-Services/Head-and-Neck-Cancer-Center/Treatment/Images/larynx_model_web-80443. jpg http: //0. tqn. com/d/np/singing/41 -1. jpg

vocal cords – air passage causes them to vibrate and produce sounds (VIDEO: http: //www. youtube. com/watch? v=-XGds 2 GAv. GQ ) �muscles tighten or loosen the flaps to control pitch �thickness and length of the vocal cords also affect sound �we shape the mouth and position the tongue to modify the sounds (some languages also use uvula) Images from: http: //www. cancer. gov/publications/patient-education/wyntk-larynx/All. Pages

Trachea �tube, about 12 cm, made of smooth muscle with “C” shaped cartilage rings to support it �gap in rings is at back against esophagus rings support the trachea while allowing esophagus to expand during swallowing Image from: http: //bastianmedicalmedia. com/wp-content/gallery/trachea/6 -trachea. jpg

Bronchi, Bronchioles, and Alveoli �trachea splits into two bronchi (also have rings) for the left and right lungs �bronchi branch into more tubes called bronchioles , and these continue to branch into subsequently smaller tubes (smaller ones lack rings) �alveolar ducts on the ends of the branches lead into chambers (air sacs) called alveoli Image from: http: //www. abpischools. org. uk/res/coresourceimport/resources 04/asthma/images/5 c 2 Alv. Brjpg. gif

Lungs �each bronchus plus all of its bronchioles and alveoli make up a lung �lungs have no muscles �are elastic and can respond passively to the action of the rib muscles and diaphragm Image from: http: //guardianlv. com/wp-content/uploads/2014/02/Human-Lungs-Being-Grown-in-Fish-Tanks-State-Texas-Scientists. jpg

�we have two lungs – the right has three lobes and the left has two (why is the left smaller? ) �well-protected by the ribs and supported by the diaphragm GIF from: http: //stream 1. gifsoup. com/view 6/4645075/lungs-breathing-o. gif

�many of the epithelial cells of the entire respiratory tract secrete mucus and have cilia to trap and remove particles �cilia beat upwards so that the mucus can be swallowed (yum!) or discharged by coughs and sneezes Image from: https: //elcaminogmi. dnadirect. com/img/content/tests/pcd/trachea. jpg

�this gets rid of potentially dangerous material, including bacteria �not always successful – people get diseases like emphysema and lung cancer – especially smokers (nicotine paralyses the cilia ) Image from: http: //media-cache-ak 0. pinimg. com/736 x/ed/00/44/ed 004490 d 4 fbfb 3 b 27 ebec 88 c 261 ab 6 b. jpg

Pleura �two membrane sacs that contain the lungs �outer sac is stuck to the inner thoracic cavity �inner sac is stuck to the lungs �are close together with a thin film of fluid between them Image from: http: //mesothelioma-navy. com/wp-content/uploads/2012/10/Pleural-mesothelioma-diagram-of-lung-Converted-300 x 300. png

The fluid is important! �isolates each lung �lubricates lungs for less friction, and the fluid tension adheres the lungs to the thoracic cavity �the fluid cannot be compressed, so the lungs follow the fluid when breathing in and out �disrupt the pleura and you can get a collapsed lung Image from: http: //www. primehealthchannel. com/wp-content/uploads/2013/03/Collapsed-lung-Picture. gif

Mechanics of Breathing

How breathing works… �we must force air in and out of the system to get air fast enough to live (diffusion is not enough) �ordinary breathing is involuntary – we do not think about it but we do have some voluntary control �the diaphragm is a dome-shaped muscle that bulges upward (located right under the lungs) �it flattens somewhat when contracted �works in unison with the intercostal muscles of the 12 pairs of ribs

Image from: https: //www. xtremepapers. com/images/gcse/biology/the_respiratory_system/inhalation_exhalation. png

Inhalation/inspiration (active) �the diaphragm and external intercostal muscles contract �diaphragm is dome-shaped when relaxed, but contracts and lowers during inhalation �intercostals pull the ribs up and outward �the volume inside lungs increases �air pressure inside the alveoli decreases, creating a partial vacuum (negative pressure) the difference in pressure between the alveoli and the atmosphere causes air to rush into the alveoli **air comes in because the lung opens up** **the lungs do not open up because air is forced in! ** �inspiration is active (contraction), but the flow of air is passive (negative pressure)

Exhalation/expiration �is usually passive no effort is required (relaxing) �the thoracic cavity is elastic – diaphragm relaxes and it recoils back into place �intercostals relax and the rib cage moves down and inward �air pushes out, lung volume drops �active expiration is possible – the inner layer of intercostal muscles can contract and force the rib cage downward and inward �also, the abdominal wall muscles can push on the viscera, and push up the diaphragm, expelling more air

OVERVIEW �diaphragm and intercostal muscles contract �ribs pull up and forward �volume of chest goes up due to negative pressure � inhale �diaphragm and intercostal muscles relax �ribs move down and inward �the volume drops because air is physically forced out � exhale