Biology: Chapter 6 Flashcards
External nares of the nose
where air enters into the respiratory tract
Nasal cavity
-filters air with mucous membranes and nasal hairs
-where air is transported after the external nares of the nose
Pharynx
-resides behind the nasal cavity and at the back of the mouth
-pathway for air and food
Larynx
-lies below the pharynx
-pathway for air
-contains two vocal cords
Epiglottis
-covers the opening of the larynx (glottis) during swallowing so food doesn’t pass through
Trachea
airway that leads from the larynx to the bronchi
Air passages of the lungs
-Bronchi (largest)
-Bronchioles
-Alveoli (where gas exchange occurs) (smallest)
Surfactant
coats each alveolus which lowers the surface tension and prevents the alveolus from collapsing on itself
Organs of the thoracic cavity
heart, lungs, esophagus, trachea, and thymus
Pleurae
-surround each lung
-form a closed sac against which the lung expands
Visceral pleura
surface adjacent to the lung (touches the lung)
Parietal pleura
outer pleura (touches other organs)
Intrapleural space
-space between visceral and parietal pleura that contains a thin layer of fluid
-helps lubricate the two pleural surfaces
Diaphragm
thin, muscular structure that divides the thoracic (chest) cavity from the abdominal cavity
Inhalation
-active process
-use diaphragm and external intercostal muscles to expand thoracic cavity
-The lungs will expand into the intrapleural space, and the pressure in the lungs will drop
-Air will then be sucked in from a higher-pressure environment
Exhalation
-not an active process
-Relaxation of the external intercostal muscles will reverse the process of inhalation
-As the diaphragm and external intercostals relax, the chest cavity decreases in volume
-This causes pressure in the intrapleural space to increase to a higher concentration than the pressure in the lungs and air will be pushed out
Speeding up exhalation
-the use of internal intercostal muscles and abdominal muscles which oppose the external intercostals and pull the rib cage down
-Decreases the volume of the thoracic cavity
Total lung capacity (TLC)
the maximum volume of air in the lungs when one inhales completely
Residual volume (RV)
the volume of air remaining in the lungs when one exhales completely
Vital capacity (VC)
the difference between the minimum and maximum volume of air in the lungs (TLC - RV)
Tidal volume
the volume of air inhaled or exhaled in a normal breath
Expiratory reserve volume (ERV)
the volume of additional air that can be forcibly exhaled after a normal exhalation
Inspiratory reserve volume (IRV)
the volume of additional air that can be forcibly inhaled after a normal inhalation
Ventilation center
-collection of neurons in the medulla oblongata that regulates ventilation
-contain chemoreceptors that are sensitive to CO2 concentration
-As the partial pressure of CO2 rises in the blood, the respiratory rate will increase so that more CO2 is exhaled
Gas exchange
-Each alveolus is surrounded by a network of capillaries
-The capillaries bring deoxygenated blood from the pulmonary arteries (originate from the right ventricle of the heart)
-The oxygenated blood returns to the left atrium of the heart via the pulmonary veins
-When it initially arrives at the alveoli, blood has low oxygen and high CO2, facilitating transfer of each down its respective concentration gradient
-No energy is required
Thermoregulation (respiratory system)
-As capillaries expand, more blood can pass through these vessels, and a larger amount of thermal energy can be dissipated
-As capillaries contract, less blood can pass through them, conserving thermal energy
Nasal cavity (immune function)
-has small hairs that help to trap particulate matter and potentially infectious particles
-contains enzymes, lysozyme, which are found in tears and saliva and is able to attack bacteria
Internal airways (immune function)
-lined with mucus which traps particulate matter and larger invaders
-underlying cilia then propel mucus up the respiratory tract to the oral cavity where it can be expelled or swallowed
Immune function of the lungs
-contain numerous immune cells including macrophages
-Mast cells have preformed antibodies on their surfaces and when the right substances attaches to the antibody, the mast cell releases inflammatory chemicals into the surrounding area to promote an immune response
Respiratory response to pH changes
-When the pH is lower and hydrogen ion concentration is higher (acidic), acid-sensing chemoreceptors just outside of the blood-brain barrier send signals to the brain to increase the respiratory rate
-An increasing hydrogen ion concentration will cause a shift in the bicarbonate buffer system, generating additional carbon dioxide which also promotes respiratory rate
-When pH is higher and hydrogen ion concentration is lower (basic), respiratory rate is slowed so more CO2 can be retained
