Gas Exchanges in the Body Internal & External Respiration Events #2 & 4

Dalton’s Law  Used to determine the individual pressures of each gas in a mixture of gases  Based on % of total of 760 mmHg of total atmospheric pressure

Dalton’s Law  Gas exchanges that occur:  Between the blood and the alveoli AND  Between the blood and the tissue cells  Takes place by simple diffusion  Depends on partial pressures of oxygen & carbon dioxide that exist on opposite sides of the exchange membrane (Dalton’s law of partial pressures)  Always flowing from high to low

Henry’s law  states that the solubility of a gas in a liquid is directly proportional to the pressure of that gas above the surface of the solution (IOW: the higher the pressure of the gas, the more gas will be shoved into the liquid thus increasing solubility)

Henry’s law  Solubility (of a gas) and partial pressure have a direct relationship

Solubility Coefficients  The solubility coefficient of the gas also affects this process – the higher the #, the more the gas “likes” to dissolve into a liquid (based on molecular structure, etc.)  Each gas will dissolve in a liquid in proportion to the ratio between its partial pressure gradient and its solubility coefficient  CO 2 =.57  O 2 =.024  N 2 =.012

2 nd Law of Thermodynamics  Solubility & temperature have an inverse relationship.  Increase in temperature causes increase in kinetic energy causes more molecular motion which allows molecules to break the intermolecular bonds and escape from solution  And vice versa

2 nd Law of Thermodynamics

Factors that Influence: Ratio Relationships  Partial pressure gradients and gas solubilities  Oxygen = has low solubility but steep partial pressure gradient (105 mmHg in alveoli – 40 mmHg in blood = 65 mmHg pressure gradient)  Carbon dioxide = has solubility ~20x greater than oxygen but partial pressure gradient is only 5 mmHg

Factors influencing internal & external respiration  Partial pressure gradients and gas solubilities  Due to the ratios of solubility coefficients and pressure gradients:  ~Equal amounts of gases are exchanged

Factors influencing internal & external respiration  Thickness of respiratory membranes  0.5 to 1.0 micrometers  edematous (swollen) tissue can be caused by congestion and pneumonia - hinders diffusion leading to hypoxia oxygen deprivation

Factors influencing internal & external respiration  Surface Area  square meters for gas exchange  Emphysema or cancer  Walls of alveoli break down  Less surface area for gas exchange

Control of Respiration

Nerves  The phrenic & intercostal nerves transmit impulses to the respiratory muscles  Irritation to phrenic nerve is responsible for hiccups (spasm of diaphragm muscle)  Neural centers are located in medulla & pons

Respiration Rate Terms  Eupnea = normal respiration rate  Approx breaths per min  Hyperpnea = higher than normal rate  Apnea = No rate  Dyspnea = general term for abnormal rate  Physical factors, conscious control, emotional factors, and chemical factors all influence rate & depth of breathing.

Hyperventilation  Deep & rapid respiration, too much CO 2 is vented out of the body so:  Not enough acid production  H 2 O + CO 2 = H 2 CO 3 (carbonic acid)  Respiratory alkalosis results  Treatment: trap the CO 2 and rebreathe it till breathing returns to normal

Hypoventilation  Slow & shallow respiration with not adequate expiration so CO 2 is not vented out of the body  Production of excess acid  H 2 O + CO 2 = H 2 CO 3 (carbonic acid)  Respiratory acidosis results  Usually caused by disease process:  COPD  Asthma  Obesity  Trauma  Pneumonia

Disorders of Respiratory System

Chronic Bronchitis  Symptoms: inflammation of mucosa – chronic mucus production

 Normal  Bronchitis

Emphysema  Breathing is very labored due to lack of alveolar recoil  End stage: Alveolar walls collapse = loss of surface area so less gas diffusion  Membranes thicken so decrease in diffusion eventually

4 features in common  Both emphysema and chronic bronchitis have:  Smoking history  Dyspnea = air hunger due to dysfunctional breathing  Coughing & pulmonary infections  Will develop respiratory failure, hypoxia, acidosis

Lung Cancer  Basic Info  1/3 of all cancer deaths are due to lung cancers  90% have a smoking history  Metastasizes VERY rapidly due to vascularity of lungs

Metastasis

3 types of lung cancer  Read the article in the textbook on page 420 about smoking and lung cancer.  Then continue on to the next slides to learn about:  Squamous cell carcinoma  Adenocarcinoma  Oat cell (small cell) carcinoma  Be sure you learn where these cancers begin and what they look like  (test question diagrams!)

Squamous cell carcinoma Begins in larger bronchi & bronchioles Forms masses that have bleeding cavities within them

Adenocarcinoma Nodules that develop in peripheral areas of lung Develop from alveolar cells & bronchial glands

Small cell carcinoma Originate in primary bronchi Grow into small grape like clusters in mediastinum Very aggressive cancer

Treatments  Resection of diseased portion of lung (thoracotomy)  Radiation therapy  Chemotherapy

Thoracotomy/lung resection

Cystic Fibrosis Genetic disorder – recessive Genetic disorder – recessive Causes oversecretion of thick mucus that clogs respiratory passages Causes oversecretion of thick mucus that clogs respiratory passages Impairs food digestion by clogging ducts that secrete enzymes Impairs food digestion by clogging ducts that secrete enzymes Multiple other organs are affected Multiple other organs are affected

Cystic Fibrosis

SIDS - Sudden Infant Death Syndrome Sudden, unexplained death of an infant less than 1 year old Sudden, unexplained death of an infant less than 1 year old Possibly caused by brain abnormalities that control respiration, heart rate, or consciousness Possibly caused by brain abnormalities that control respiration, heart rate, or consciousness Environmental factors to reduce risks – sleep on back not on stomach, firm crib with no blankets or stuffed animals or pillows Environmental factors to reduce risks – sleep on back not on stomach, firm crib with no blankets or stuffed animals or pillows Sudden infant death syndrome (SIDS): Risk factors - MayoClinic.com Sudden infant death syndrome (SIDS): Risk factors - MayoClinic.com Sudden infant death syndrome (SIDS): Risk factors - MayoClinic.com Sudden infant death syndrome (SIDS): Risk factors - MayoClinic.com

Asthma Chronically inflamed hypersensitive bronchial passageways Chronically inflamed hypersensitive bronchial passageways Bronchoconstriction of passageways in response to allergen, temperature changes, & exercise Bronchoconstriction of passageways in response to allergen, temperature changes, & exercise Can be managed with medication Can be managed with medication

Hyperbaric Conditions  Hyperbaric oxygen chambers – designed to force greater amounts of oxygen into patient’s blood  Treats tissues affected by poor circulation

How Hyperbaric Treatment Works  Patient breathes in regular air while body is under pressure  Increased pressure means increased solubility of gases (incl oxygen)  More oxygen in blood benefits treatment of certain conditions

HBOT used to treat: TetanusGangreneMigraines Slow healing wounds Burns/skin grafts StrokeAutism Traumatic Brain Injury Decompression Sickness Cerebral Palsy Multiple Sclerosis Fibromyalgia Many other conditions

Scuba Diving The Physics of Diving - Scuba Gas Laws The Physics of Diving - Scuba Gas Laws As you go down in depth, the water puts pressure on your bodyAs you go down in depth, the water puts pressure on your body Increased pressure = increased solubility of inhaled gases into the bloodIncreased pressure = increased solubility of inhaled gases into the blood

Scuba Diving As you come up at the correct rate, the pressure decreases slowlyAs you come up at the correct rate, the pressure decreases slowly So the solubility decreases slowlySo the solubility decreases slowly So the gases come out of the bloodSo the gases come out of the blood And you can exhale themAnd you can exhale them

Scuba Diving If you come up too rapidly, the pressure decreases rapidlyIf you come up too rapidly, the pressure decreases rapidly So the solubility decreases rapidlySo the solubility decreases rapidly So the gases come out of the blood too fast to exhale them properlySo the gases come out of the blood too fast to exhale them properly The excess gas bubbles can collect in joint spaces, arteries, tissues, etc. causing coronary, pulmonary, or brain embolismsThe excess gas bubbles can collect in joint spaces, arteries, tissues, etc. causing coronary, pulmonary, or brain embolisms

Nitrogen Narcosis As you descend under the water, the pressure on your body increases, so more nitrogen and oxygen dissolve in your blood. Most of the oxygen gets consumed by your tissues, but the nitrogen remains dissolved. Excess nitrogen causes a feeling of euphoria similar to laughing gas – impairs judgement

Decompression Sickness DCS arises when the pressure gradient for nitrogen leaving the tissues is so great that large bubbles form in venous circulation DCS symptoms are wide-ranging: from skin mottling to mild tingling in the hands or feet to shock and death Recompression in hyperbaric chamber is only effective treatment

High Altitude Sickness The higher the altitude, the less the amount of oxygen present in the air.The higher the altitude, the less the amount of oxygen present in the air. Headache and difficulty breathing are initial symptoms.Headache and difficulty breathing are initial symptoms. HA pulmonary edema and HA cerebral edema are life threatening symptoms.HA pulmonary edema and HA cerebral edema are life threatening symptoms. Body responds over time by increasing erythropoiesis to give body greater oxygen carrying capacity.Body responds over time by increasing erythropoiesis to give body greater oxygen carrying capacity.