Respiratory System Flashcards
Nares
Nostrils; where gas enters the nose
Nasal Cavity
Mucous membranes and nasal hair filter air
Pharynx
Warms and humidifies the air; also separates food and air pathways
Larynx
Opening is termed the glottis and is covered by the epiglottis during swallowing
Trachea
Air from the larynx moves through here on its way to the bronchus
Bronchus
Bronchus divides into smaller branches of bronchioles
Alveoli
- Tiny balloon like structures at the end of the bronchioles where gas exchange occurs
- Surrounded by a network of capillaries to carry O2 and CO2
Attractant
Detergent that lowers surface tension and prevents the Alveoli from collapsing on itself
Pleurae
Membranes the surround each lung ; a closed sac against which the lungs expand
Interpleural Space
Space within sac filled with fluid to lubricate pleural surfaces
Diaphragm
Thin muscular structure that divides thoracic (chest) cavity and abdominal cavity generating negative pressure for expression
Inhalation
Active Process where the diaphragm flattens and the external intercostal muscles expand the thoracic cavity, increasing volume of interpleural space thus decreasing the intrapleural pressure
Negative Pressure Breathing
Pressure differential (lungs @ higher than 1 atm) so the lungs expand into the space dropping their pressure and drawing in air from the environment
**Remember Boyle’s Law P is inversely related to volume
Passive Exhalation
Relaxation of muscles of inspiration and elastic recoil of lungs allow the chest cavity to decrease in volume, reversing the pressure differentials see in inhalation
- Pressure in interpleural space is higher than pressure in lungs (1 atm) so air is pushed out
Active Exhalation
Internal Intercostal Muscles and Abdominal Muscles pull the rib cage down by opposing the External Intercostal Muscles and forcibly decreases the volume in the thoracic cavity ; speeding up the process of ventilation and pushing air out
Spirometer
Used to measure lung capacities and volume
Total Lung Capacity (TLC)
Max volume of air in the lungs when one inhales completely (6-7L)
Residual Volume (RV)
Minimum volume of air in lungs when one exhales completely
Vital Capacity (VC)
Difference between min and max volumes
VC =(TLC - RV)
Tidal Volume (TV)
Volume of air exhaled or inhaled in a normal breath
Expiratory Reserve Volume (ERV)
Volume of additional air that can be forcibly exhaled after normal exhalation
Inspiratory Reserve Volume (IRV)
Volume of additional air that can be forcibly inhaled after normal inhalation
Ventilation Center
Neurons in the medulla oblongata that fire rhythmically to cause regular contraction of respiratory muscles; contain chemo-receptors sensitive to [CO2]
Hypercarbia
Abnormally elevated CO2 levels; causing the respiratory rate to increase to expel the excess CO2
Cerebrum
Allows limited control of our own breathing
Functions of Respiratory System
- Gas Exchange
- Thermoregulation
- Immune Function
- pH Control
Gas Exchange Function of Respiratory System
Deoxygenated blood from right ventricle of the heart goes into pulmonary arteries and then travels to the alveoli through capillaries. Oxygenated blood returns to the left atrium of the heart via the pulmonary veins
Thermoregulation Function of Respiratory System
Vasodilation (capillary expand and more blood passes through causing thermal energy to dissipate)
- Vasoconstriction (capillary contract, less blood passes through to preserve thermal energy)
Immune Function of Respiratory System
- Vibrissae (nasal hairs) can trap particulate matter and infectious particles
- Lysozyme attacks bacteria
- Mucus lines internal airways to trap particulate matter and larger invaders
- Cilia propel mucus up respiratory tract to oral cavity where it can be expelled or swallowed
Vibrissae
Small hairs that line the nasal cavity
Lysozyme
Attack peptidoglycan walls of gram + bacteria
Mast Cells
Pre-formed antibodies which can release inflammatory chemicals in surrounding area to create immune response
Bicarbonate Buffer System
CO2 (g) + H2O (l) H3CO3 (aq) H+ (aq) + HCO3 (aq)
- Keeps the blood pH around 7.4
Acidemia
Low pH (increased [H+] )
- Shifts bicarbonate system to generate additional CO2
- Respiratory rate increases
Alkalemia
High pH (decreased [H+] )
- Shifts bicarbonate system to the right
- CO2 is retained
- Respiratory rate is slowed
