Pathway of Air/ O2 Nose – external nares → nasal cavity → internal nares  Pharynx – nasopharynx → oropharynx → laryngopharynx Larynx – epiglottis → larynx Trachea – trachea Bronchi – primary bronchi → secondary bronchi → tertiary bronchi → bronchioles Lungs – alveoli → blood stream 3/17/08

Pathway of Air/ O2 Each component is composed of special tissues which aid in their function Passageways & accessory structures in the nose and pharynx = upper respiratory system Nose: external & internal nose Outside: cartilage & skin structure with 2 openings = external nares Directs air into nasal passageways External = object of “vanity’ “nose job” = Rhinoplasty – surgery to repair or alter nose structure – involves addition or removal of tissue Involves inconspicuous incisions & local anesthesia 3/17/08

Pathway of Air/ O2 - Skull Nostrils lead into 2 chambers separated by the nasal septum Right and left chambers of the nasal cavity Walls of the nasal septum = ethmoid & vomer bones Protrusions of the bone = nasal conchae (superior, middle, inferior) Allows air to swirl in the nasal cavity – airborne particles get trapped in mucus Cavity is lined with mucous membrane Mucus is secreted by the paranasal sinuses (=air cavity with epithelium in the skull) Floor of the nasal cavity = hard palate (roof of the mouth) 3/17/08

Function of the Nose Directs air into the nasal passageway Warms air via blood circulation Location for olfaction sensation Traps particles & microbes = non-specific defense These then get swallowed with mucous 3/17/08

Pathway of Air/ O2 – Pharynx and on From the nasal cavity, air enters internal nares then the pharynx (throat) Pharynx Shared by digestive and respiratory systems It is a muscular tube lined with mucous epithelium Just behind the nasal cavity = nasopharynx The oropharynx is located right under the soft palate – base of the tongue at the opening of the throat It is lined with stratified squamous epithelium (b/c it is shared with the digestive system Fig. 21.3 3/17/08

Pathway of Air/ O2 – Pharynx and on Laryngopharynx Below oropharynx = cavity Opening to esophagus & trachea Common area for air & food Stratified squamous epithelium Next air enters the Larynx Top of the trachea Epiglottis = elastic cartilage Allows distinguish food vs. air It closes the glottis (opening of the larynx) if food is passing into the pharynx The ligaments stretch during swallowing to prevent food from entering the nasal passageway Fig. 21.5 Fig. 21.3 3/17/08

Pathway of Air/ O2 – Larynx (& sound) Cylinder made of cartilage, ligaments & skeletal muscle Note large pieces of hyaline cartilage The larynx contains 2 ligaments stretched from cricoid cartilage to thyroid cartilage = vocal ligaments (commonly called “vocal cords” Air brushes against the vocal cords and creates vibrations = sound The Larynx is important for air passage and speech Skeletal muscles lengthen and shorten vocal cords – produces different sounds Fig. 21.4 3/17/08

Pathway of Air/ O2 – Trachea aka “windpipe” Tube made of smooth muscle from larynx to bronchi Supported by cartilage rings C-shaped cartilage – open at back = flexibility & expansion Posterior wall – pseudostratified epithelium Bifurcation at bottom of trachea (into 2) Ridge @ the bifurcation =carina Contains the cough reflex center 2 branches = Primary bronchi (to right and left lung) Cartilage rings support the bronchi Fig. 21.6 3/17/08

Pathway of Air/ O2 – Bronchi Primary bronchi Each Primary bronchi branches into secondary (lobar) bronchi These go to individual lobes of the lung These then branch into the tertiary (segmental) bronchi These are branches within each lobe Branch to bronchioles End in lobules The bronchi regulate the air flow through the lungs Bronchitis = infection/inflammation of the bronchi Acute bronchitis is usually caused by a virus (sometimes by bacteria) Cough, mild fever, yellow/green mucous Fig. 21.9 3/17/08

Pathway of Air/ O2 – Lung Collection of lobules containing alveoli Air sacs = light consistency Whole lung = paired organ - Right and left side Each lung is divided into lobes Right = divided into 3 lobes by fissures Left = divided into 2 lobes (know names of fissures and lobes for lab) The shape of the lungs accommodates neighboring organs Heart is slightly to left = left lung is less broad & has cardiac notch Right side – liver is just below diaphragm = right lung is shorter Fig. 21.7 3/17/08

Pathway of Air/ O2 – Lung Flat base at the bottom, pointed apex at the top Each lung is covered by a pleural membrane on the outside Review characteristics of pleural cavity Medial surface of lungs = surface in middle Entry point for bronchi & blood vessels (Hilus) Primary bronchus and pulmonary arteries & veins Fig. 21.7 3/17/08

Pathway of Air/ O2 – Lung Bronchus divides further inside the lungs – to each lobe Divided into segments within each lobe Bronchopulmonary segment Visceral pleura extends into the lung – divides segments into smaller sections Each section = Pulmonary lobule Each lobule Contains a cluster of alveoli Receives air from the Bronchioles Lymph vessel circulation Pulmonary arteries and venules Each alveolus within each lobule Hollow air sac Two or more air sacs may share a common opening = alveolar sac Recall what you saw in lab… Fig. 21.9 3/17/08

Alveoli In Pulmonary Lobule Fig. 21.9 3/17/08

Pathway of Air/ O2 – Alveoli Alveoli = location of gas exchange Each alveolus – is confined – consists of a layer of simple squamous epithelium Epithelium also contains Macrophages- to engulf any escaped pathogens Septal cells – special cells that secrete a liquid called surfactant A surfactant keeps alveoli from collapsing shut There is a continuous capillary adjacent to each alveolus These are connected by fused basement membranes of epithelial cells & endothelial cells Gas crosses 3 layers CO2 enters alveolus & O2 enters capillary 3/17/08

Respiratory System Chapter 21 – Day 3 3/17/08

Alvioli – Capillary Interface Fig. 21.11 3/17/08

Mechanics of Respiration Ventilation = mechanical process involves the diaphragm and skeletal muscles (intercostal muscles) Breathing consists of 2 phases: Inspiration air is taken into the lungs Expiration Air passes out of the lungs 3/17/08

Mechanics of Respiration Air is moving in & out because of pressure gradients Air flows from high pressure to low pressure… For air to enter the lungs, pressure should be low in the lungs EXPANSION of lungs lowers pressure The Diaphragm contracts – pushed down = opens space in the lungs External intercostal muscles contract – elevates chest Pulls on parietal pleura Pulls on visceral pleura Expands space into the lung The pressure gradient forces air into the lungs (insp) ACTIVE process – powered by muscle 3/17/08

Mechanics of Respiration Inspiration = ACTIVE process – powered by muscle Expiration = PASSIVE process Objective = increase pressure in lungs to create high pressure gradient in TO out… The diaphragm and intercostals relax Pushes against pleura – close in on lungs Imagine a full balloon with hands pushing against it Increased pressure in lungs forces air out Process of regular breathing Deep breathing & forced expiration require additional muscles – abdominal muscles 3/17/08

Mechanics of Respiration The amount of air entering during breathing depends on several factors COMPLIANCE – degree of expandability of lungs Large compliance – more air enters Elastic fibers surround alveoli & surfactant in alveoli contribute to compliance & mobility of thoracic cage Less surfactant – alveoli collapse – decreases comp. Less elasticity = increases compliance Emphysema Shortness of breath, weak at exertion Destruction of alveolar surface = loss of elasticity Merged alveoli = larger space, but not enough capillary support, so gas exchange does not support demand Skeletal disorders Arthritis or rib injuries reduce compliance 3/17/08

Lung mechanics Fig. 21.13 3/17/08

Lung mechanics Fig. 21.14 3/17/08

Lung mechanics Fig. 21.15 3/17/08

Lung mechanics Fig. 21.16 3/17/08

Ventilation Occurs at a programmed rhythm Inspiration every ___ seconds Normal breathing is called Eupnea This rhythm (a.k.a. your breathing) is controlled by the pons & medulla in the brain Fig. 21.26 3/17/08

Ventilation Medulla Rhythmicity area 2 centers Control neurons of diaphragm & intercostals Quiet breathing = Eupnea inspiration every 5 sec. Centers are activated then inhibited Also involved in forced breathing (hyperpnea) – other controls are also involved here Fig. 21.26 3/17/08

Ventilation Pons Pneumotaxic & apneustic areas Adjust activity of the respiratory centers Adjusts rate & depth of respiration Fig. 21.26 3/17/08

Ventilation Other, additional controls can change rhythm Conscious control Cerebrum sends action potential to respiratory centers Stretch receptors in chest Chemoreceptors Sense change in blood CO2/O2 concentration Autonomic nervous system Accelerates or slows down breathing Problems with neural control in ventilation can result in apnea = breathing stops for long periods (sleep apnea) 3/17/08

Homeostatic controls (response to changes in PCO2) Fig. 21.27 3/17/08

Gas Exchange Very important activity in the lungs = gas exchange between the alveoli & capillaries O2 enters blood vessel whileCO2 enters alveolus Driving force = pressure gradient Partial pressure of individual gases… Know what is high/low in lungs vs. tissues What will move? which way? where? O2 & CO2 uptake is different Fig. 21.19 3/17/08

Gas Exchange O2 uptake in the lungs The next step is transportation O2 enters blood by simple diffusion because of the concentration gradient & the partial pressure gradient The next step is transportation RBCs contain hemoglobin = high affinity for O2 When O2 enters blood: 98.5% binds to hemoglobin 1.5% remains in plasma Remember each Hb has 4 heme groups = 4 Fe2+ Max. of 4 O2 can bind to one Hb protein but…. There are 280 million Hb in one RBC! Fig. 21.24 3/17/08

Saturation If all hemoglobin molecules are bound to full capacity = 100% saturation of O2 in the blood Partial saturation = not all Hb has O2 Thus the blood is not carrying up to it’s maximum Why would that ever happen? Saturation is affected by many factors Fig. 21.20 3/17/08

Saturation Partial pressure of O2 Higher PO2, more saturation Even at 60mg Hg At higher altitudes you get low PO2, so the body produces more RBCs to compensate Saturation is affected by many factors Fig. 21.18 3/17/08

Saturation pH of blood Bohr effect High pH – blood is more alkaline More O2 binding = more saturation Low pH – blood is more acidic O2 is released from Hb = less saturation Bohr effect CO2 makes blood more acidic When CO2 is high, O2 is low O2 goes to tissues as CO2 enters blood The Bohr Effect is an adaptation in animals to release oxygen in the oxygen starved tissues in capillaries where respiratory carbon dioxide lowers blood pH. When blood pH decreases, the ability of hemoglobin to bind to oxygen decreases. Hemoglobin binds to oxygen in the oxygen-rich atmosphere of the lungs, and releases it in the oxygen-poor environment of the tissues. The primary function of hemoglobin is to carry oxygen from the lungs to tissues. The Bohr Effect aids in this function by releasing oxygen to the tissues when the concentration of hydrogen ions becomes large. At low pH the Bohr Effect allows the blood to unload oxygen for use by the muscles. Therefore, the Bohr Effect is necessary for the body to function. Fig. 21.21 3/17/08

Saturation Temperature Reaction products Higher temp. = less saturation General property of gases in solution O2 is released to tissues If O2 levels are low in the blood the amount that is released is reduced by vasoconstriction This is the response during shock Reaction products O2 is used for glycolysis More consumption of O2 = higher concentration of glycolysis products = lower saturation in blood and more O2 needed in cells The Bohr Effect is an adaptation in animals to release oxygen in the oxygen starved tissues in capillaries where respiratory carbon dioxide lowers blood pH. When blood pH decreases, the ability of hemoglobin to bind to oxygen decreases. Hemoglobin binds to oxygen in the oxygen-rich atmosphere of the lungs, and releases it in the oxygen-poor environment of the tissues. The primary function of hemoglobin is to carry oxygen from the lungs to tissues. The Bohr Effect aids in this function by releasing oxygen to the tissues when the concentration of hydrogen ions becomes large. At low pH the Bohr Effect allows the blood to unload oxygen for use by the muscles. Therefore, the Bohr Effect is necessary for the body to function. Fig. 21.21 3/17/08

Saturation Exercise Other influences Combined effect ↑ exercise - ↓ saturation ↑ respiration rate, but… Temperature is increased Lactic acid lowers pH – lower pH = less O2 bound to Hb – releasing at tissues Other influences Surface area of alveoli exposed to capillaries Rate of respiration (inhaling & exhaling) b/c also affects blood pH The Bohr Effect is an adaptation in animals to release oxygen in the oxygen starved tissues in capillaries where respiratory carbon dioxide lowers blood pH. When blood pH decreases, the ability of hemoglobin to bind to oxygen decreases. Hemoglobin binds to oxygen in the oxygen-rich atmosphere of the lungs, and releases it in the oxygen-poor environment of the tissues. The primary function of hemoglobin is to carry oxygen from the lungs to tissues. The Bohr Effect aids in this function by releasing oxygen to the tissues when the concentration of hydrogen ions becomes large. At low pH the Bohr Effect allows the blood to unload oxygen for use by the muscles. Therefore, the Bohr Effect is necessary for the body to function. 3/17/08

CO poisoning Hb has a high affinity for O2,BUT it also has a high affinity for CO (carbon monoxide) Problem is CO binds but cannot be released from Hb as easily as O2 CO poisoning CO bound to Hb Therefore less O2 saturation Less O2 delivered Condition = HYPOXIA Symptoms: headache, dizziness, gasping Another cause for hypoxia is atelectasis Collapsed alveoli Blockage (internal) of bronchiole or bronchus (tumor, lymph node, mucus plug) The Bohr Effect is an adaptation in animals to release oxygen in the oxygen starved tissues in capillaries where respiratory carbon dioxide lowers blood pH. When blood pH decreases, the ability of hemoglobin to bind to oxygen decreases. Hemoglobin binds to oxygen in the oxygen-rich atmosphere of the lungs, and releases it in the oxygen-poor environment of the tissues. The primary function of hemoglobin is to carry oxygen from the lungs to tissues. The Bohr Effect aids in this function by releasing oxygen to the tissues when the concentration of hydrogen ions becomes large. At low pH the Bohr Effect allows the blood to unload oxygen for use by the muscles. Therefore, the Bohr Effect is necessary for the body to function. 3/17/08

Transport of CO2 in the blood Very different from O2 transport O2 is mostly bound to Hb Only 23% of CO2 is bound to hemoglobin 7% is in plasma as CO2 – as dissolved gas The majority of CO2 (70%) is converted to carbonic acid = H2CO3 … The Bohr Effect is an adaptation in animals to release oxygen in the oxygen starved tissues in capillaries where respiratory carbon dioxide lowers blood pH. When blood pH decreases, the ability of hemoglobin to bind to oxygen decreases. Hemoglobin binds to oxygen in the oxygen-rich atmosphere of the lungs, and releases it in the oxygen-poor environment of the tissues. The primary function of hemoglobin is to carry oxygen from the lungs to tissues. The Bohr Effect aids in this function by releasing oxygen to the tissues when the concentration of hydrogen ions becomes large. At low pH the Bohr Effect allows the blood to unload oxygen for use by the muscles. Therefore, the Bohr Effect is necessary for the body to function. Fig. 21.23 3/17/08

Transport of CO2 in the blood The Bohr Effect is an adaptation in animals to release oxygen in the oxygen starved tissues in capillaries where respiratory carbon dioxide lowers blood pH. When blood pH decreases, the ability of hemoglobin to bind to oxygen decreases. Hemoglobin binds to oxygen in the oxygen-rich atmosphere of the lungs, and releases it in the oxygen-poor environment of the tissues. The primary function of hemoglobin is to carry oxygen from the lungs to tissues. The Bohr Effect aids in this function by releasing oxygen to the tissues when the concentration of hydrogen ions becomes large. At low pH the Bohr Effect allows the blood to unload oxygen for use by the muscles. Therefore, the Bohr Effect is necessary for the body to function. Fig. 21.23 3/17/08

Transport of CO2 in the blood This process alone would create a high “-” charge in the plasma To balance the charge a chloride shift occurs Cl- is exchanged for HCO3- This keeps ions balanced KCl is formed = buffer effect HCO3-, CO2 in plasma, CO2 on Hb are all transported to the lungs The H+ in the blood makes it acidic, low pH At the alveoli HCO3- has to be changed back to CO2 The Bohr Effect is an adaptation in animals to release oxygen in the oxygen starved tissues in capillaries where respiratory carbon dioxide lowers blood pH. When blood pH decreases, the ability of hemoglobin to bind to oxygen decreases. Hemoglobin binds to oxygen in the oxygen-rich atmosphere of the lungs, and releases it in the oxygen-poor environment of the tissues. The primary function of hemoglobin is to carry oxygen from the lungs to tissues. The Bohr Effect aids in this function by releasing oxygen to the tissues when the concentration of hydrogen ions becomes large. At low pH the Bohr Effect allows the blood to unload oxygen for use by the muscles. Therefore, the Bohr Effect is necessary for the body to function. Fig. 21.23 3/17/08

Transport of CO2 – at the alveoli HCO3- has to be changed back to CO2 HCO3- re-enters the RBC where it reacts with H+ ions CO2 and H2O are produced Cl- splits from K+ - returns to plasma As a result of all of this The pH of the blood increases (= more basic) High pH favors O2 saturation CO2 gas leaves the blood vessel - CO2 in plasma & on HB diffuse out Good general overview of O2 and CO2 transport Fig. 21.24 The Bohr Effect is an adaptation in animals to release oxygen in the oxygen starved tissues in capillaries where respiratory carbon dioxide lowers blood pH. When blood pH decreases, the ability of hemoglobin to bind to oxygen decreases. Hemoglobin binds to oxygen in the oxygen-rich atmosphere of the lungs, and releases it in the oxygen-poor environment of the tissues. The primary function of hemoglobin is to carry oxygen from the lungs to tissues. The Bohr Effect aids in this function by releasing oxygen to the tissues when the concentration of hydrogen ions becomes large. At low pH the Bohr Effect allows the blood to unload oxygen for use by the muscles. Therefore, the Bohr Effect is necessary for the body to function. 3/17/08

Hyperventilation Hyperventilation = Rapid breathing Air is moving in & out of the lungs very fast HCO3- leaves blood faster at the lungs as CO2 Results in an increase in pH = Alkalosis, b/c PCO2 is low At a high pH O2 remains bound to Hb, not released at tissues Can result in dizziness, unconsciousness So, how does breathing into a bag help? Breathing in the bag, you breath in CO2 Which decreases blood pH – thus you release O2 at tissues… The Bohr Effect is an adaptation in animals to release oxygen in the oxygen starved tissues in capillaries where respiratory carbon dioxide lowers blood pH. When blood pH decreases, the ability of hemoglobin to bind to oxygen decreases. Hemoglobin binds to oxygen in the oxygen-rich atmosphere of the lungs, and releases it in the oxygen-poor environment of the tissues. The primary function of hemoglobin is to carry oxygen from the lungs to tissues. The Bohr Effect aids in this function by releasing oxygen to the tissues when the concentration of hydrogen ions becomes large. At low pH the Bohr Effect allows the blood to unload oxygen for use by the muscles. Therefore, the Bohr Effect is necessary for the body to function. 3/17/08

Hypoventilation Hypoventilation Slow breathing Results in low pH = acidosis HCO3- remains in the blood O2 is released before it can be transported to the tissues BECAUSE – high pH = low saturation of O2 on Hb – released and not reaching tissues The Bohr Effect is an adaptation in animals to release oxygen in the oxygen starved tissues in capillaries where respiratory carbon dioxide lowers blood pH. When blood pH decreases, the ability of hemoglobin to bind to oxygen decreases. Hemoglobin binds to oxygen in the oxygen-rich atmosphere of the lungs, and releases it in the oxygen-poor environment of the tissues. The primary function of hemoglobin is to carry oxygen from the lungs to tissues. The Bohr Effect aids in this function by releasing oxygen to the tissues when the concentration of hydrogen ions becomes large. At low pH the Bohr Effect allows the blood to unload oxygen for use by the muscles. Therefore, the Bohr Effect is necessary for the body to function. 3/17/08

Respiratory Disorders Common cold Affects upper respiratory region Rhinovirus & adenovirus Pneumonia Inflammation of lobules Fluid leaks into alveoli Constricts bronchi Usually occurs when defense system is weak Pathogens escape “filtering” process Typically caused by bacteria, fungi The Bohr Effect is an adaptation in animals to release oxygen in the oxygen starved tissues in capillaries where respiratory carbon dioxide lowers blood pH. When blood pH decreases, the ability of hemoglobin to bind to oxygen decreases. Hemoglobin binds to oxygen in the oxygen-rich atmosphere of the lungs, and releases it in the oxygen-poor environment of the tissues. The primary function of hemoglobin is to carry oxygen from the lungs to tissues. The Bohr Effect aids in this function by releasing oxygen to the tissues when the concentration of hydrogen ions becomes large. At low pH the Bohr Effect allows the blood to unload oxygen for use by the muscles. Therefore, the Bohr Effect is necessary for the body to function. 3/17/08

Respiratory Disorders Cystic fibrosis Dense, viscous mucus production Cannot be moved efficiently through respiratory passageway Respiratory defense is not efficient Risk for infection is very high It is largely a genetic disorder Tuberculosis Affects a large population globally It is a bacterial infection of the lungs (Notes from lab) Responsible for many deaths world-wide and once was quite bad in U.S. – new antibiotic-resistant strains of TB… Emphysema, Lung cancer – in book, page 649… The Bohr Effect is an adaptation in animals to release oxygen in the oxygen starved tissues in capillaries where respiratory carbon dioxide lowers blood pH. When blood pH decreases, the ability of hemoglobin to bind to oxygen decreases. Hemoglobin binds to oxygen in the oxygen-rich atmosphere of the lungs, and releases it in the oxygen-poor environment of the tissues. The primary function of hemoglobin is to carry oxygen from the lungs to tissues. The Bohr Effect aids in this function by releasing oxygen to the tissues when the concentration of hydrogen ions becomes large. At low pH the Bohr Effect allows the blood to unload oxygen for use by the muscles. Therefore, the Bohr Effect is necessary for the body to function. 3/17/08