Part 1 – The Upper Respiratory Tract RESPIRATORY SYSTEM Part 1 – The Upper Respiratory Tract

Primary Functions Gas Exchange (oxygen and CO2) Voice Production Olfaction - Sense of smell Control blood pH (using CO2)

Gas Exchange – Main Steps Move air into lungs External respiration – exchange O2 & CO2 with blood and air Move gases through blood flow Internal respiration – exchange O2 & CO2 with body cells and blood

Main Players Upper Tract: Lower Tract: Nose Nasal Cavity Pharynx Larynx Trachea Bronchial Tubes Lungs alveoli

The Nose Nasal Cavity – hollow space behind nose Warms Air Filters Air Divided into two nostrils by nasal septum The inside of your nose is lined with mucosa that produces sticky mucus Nose Job…

ParanasalSinuses Spaces within the facial bones Makes the skull lighter Helps with speech Produces mucus The bones… Maxillary Frontal Ethmoid sphenoid

Nasal Conchae The conchae increase surface area so more air is filtered and warmed The filtered particles (dust, etc.) are swallowed

Rhinitis Rhinitis is excessive mucus production caused by… Cold viruses allergens Sinusitis or sinus infection can lead to temporary changes in your voice and headaches called sinus headaches

Pharynx The common passage way for food and air The tonsils are located here

Larynx Just below the pharynx The top of the trachea Contains the vocal cords Protected by muscles and cartilage. Also called…the Adam’s Apple See Steve Tyler Video Clip

Glottis – triangular slit that opens during breathing/talking, and closes during swallowing  Epiglottis – flaplike structure that stands upright, allows air to enter larynx, during swallowing it presses downward and prevents food from entering air passages

The Respiratory System Part 2 – Lower Tract

The Big Picture

The Main Players: Trachea > Primary bronchi--> bronchioles --> alveolar ducts -->  alveoli                                                                        

Alveoli & Lungs

ALVEOLI

The Trachea About 10 cm or 4” in length Is also called the “windpipe” Is reinforced by C-shaped cartilaginous rings that prevent the trachea from collapsing during each breath Is lined with pseudostratified ciliated columnar epi

Primary Bronchi The trachea has a “fork in the road” and splits to become the right & left main or primary bronchi The right primary bronchus is wider, shorter, and bit straighter than the left – food can get caught here if inhaled

LUNGS - spongy tissue that sit within the pleural cavity

Serous fluid lubricates lungs during breathing Right Lung          = 3 lobes Left Lung           = 2 lobes Serous fluid lubricates lungs during breathing Apex Base

Bronchi to Alveoli The main bronchi subdivide into smaller and smaller tubes eventually entering the smallest tubes called bronchioles Terminal bronchiole lead into respiratory bronchioles that lead into the blind air sacs called alveoli

Gas Exchange Respiratory Zone: the only site of exchange of O2 and CO2 The area where you find the respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli All the other passages are called conducting zones

The Respiratory Membrane This membrane is the alveolar and capillary walls The walls of the alveoli are a single layer of squamous epi cells – so thin that gas exchange is by simple diffusion Most of your lungs are made up of this membrane Alveolar macrophages, white blood cells that “sweep” up dust and foreign invaders You also have cuboidal cells that produce a fat called a surfactant that keeps the membrane moist to facilitate diffusion

Breathing Mechanics Breathing is a completely mechanical process It works by changing the volume and thus the pressure of the thoracic cavity There are two phases in breathing: inspiration, air flowing in and expiration, air flowing out

1.  Diaphragm moves down, forcing air into airways 2.  Intercostals contract, enlarging cavity even more 3.  Membranes move with the contractions 4.  Surface tension in alveoli and surfactant keep them from collapsing 5.  Other muscles (pectoralis minor and sternocleidomastoid) can force a deeper breath 6.  The first breath in newborns is the hardest due to low surfactant

ATMOSPHERIC PRESSURE = 760 Hg Pressure is necessary for breathing, which is why it is difficult to breathe in high altitudes and also why a punctured lung can be dangerous. A hole in the pleural cavity can cause the lung to collapse or deflate

EXHALATION As the diaphragm and other muscles relax, ELASTIC RECOIL from surface tension forces air out.     Muscles can force extra air out or in

NON-RESPIRATORY MOVEMENTS Coughing, sneezing, laughing, crying Hiccup - spasm of the diaphragm Yawn - possibly causes by low oxygen levels

Also check out this procedure where  fluid is drained from the lungs - not for those with a weak stomach!

The Respiratory System Part 3: Respiratory Volumes to Control of Respiration

Respiratory Air Volumes Spirometry - measures the amount (volume) of air moving in and out of the lungs Respiratory Cycle - 1 inspiration and 1 expiration

Measured by Spirometry: Tidal Volume (TV)  -  amount of air that enters the lungs during one cycle during a normal breath Expiratory Reserve Volume (ERV) – air that can be exhaled after a normal exhalation Inspiratory Reserve Volume (IRV) – the amount of air that can be inhaled after a normal inhalation   Using a spirometer

Human lung size is determined by genetics, gender, and height Maximum capacity of an average lung is around 6 liters of air – though your lungs rarely operate at maximum capacity Air in the lungs is measured in terms of lung volumes and lung capacities Volume measures the amount of air for function (like TV) and capacity is any two or more volumes Ex., Vital Capacity (ERV + TV + IRV), Inspiratory capacity (TV + IRV), Functional Residual Capacity (ERV + RV), and total lung capacity (RV + ERV + TV + IRV) Residual Volume (RV) is a lung volume of the amount of air left in the lungs after a forced exhalation – it can’t be measured, only calculated

Capacities

Normal Lung Capacities

Image adapted from http://www.arthursclipart.org/

(based in the medulla and the pons) Breathing is involuntary, but muscles are under voluntary control Respiratory Center – groups of neurons in the brain that control inspiration and expiration (based in the medulla and the pons)

Medulla Rhythmicity Area   Dorsal Respiratory Group       (rhythm)    Ventral Respiratory Group       (forced) Pneumotaxic Area (pons) - inhibit 

Factors Affecting Breathing *Chemosensitive areas – detect concentrations of chemicals like carbon dioxide and hydrogen 1. Rise in CO2 2. Low blood oxygen (peripheral chemoreceptors, carotid and aortic bodies, sense changes) 3. Inflation reflex – regulates the depth of breathing, prevents overinflation of the lungs 4. Emotional upset, fear and pain

Hyperventilation - increase breathing, lower CO2 concentration Breathing into a bag can restore CO2 concentrations

Hypoxia is a disease in which there is an overall lack of oxygen content within the body's tissue and vital human organs (specifically the brain). Hypoxia has several potential causes, including: cardiac arrest, severe head trauma, carbon monoxide poisoning, suffocation, strangulation, and choking, as well as any instance in which oxygen supply is deprived from the body. Asphyxia is a condition of severely deficient supply of oxygen to the body that arises from being unable to breathe normally. An example of asphyxia is choking. Asphyxia causes generalized hypoxia, which primarily affects the tissues and organs.

ILLNESSES RELATED TO THE RESPIRATORY SYSTEM 1. Cystic Fibrosis (genetic) 2. Asthma 3. Bronchitis 4. Apnea 5. Emphysema 6. Lung Cancer 7. Altitude Sickness 8. Chronic Obstructive Pulmonary Disease (COPD) 9. Sinusitis 10. Bacterial or Viral Infections (cold, flu, pneumonia)