4. Respiratory system Flashcards
Describe the route of oxygen from the air into the alveoli
nostrils > nasal cavity > the pharynx > the larynx > the glottis > the trachea > the bronchi > bronchioles > alveoli
How does oxygen get from the alveoli to the blood?
Oxygen diffuses through the membrane from the alveoli to the blood and carbon dioxide diffuses from the blood to the alveoli
What is the air presssure at the end of inhalation in the alveoli om mammas?
about 101 kPa, equal to atmospheric pressure
What are the two membranes that surround each lung?
Each lung is surrounded by the pleura. The parietal pleura is attached to the inside of the chest wall, the visceral pleura is attached to the surface of the lungs. Van buiten naar binnen: eerst parietal, dan visceral
What is the mediastinum?
Separating the two lungs is a region of tissue that contains the oesophagus, trachea, aorta, vena cava and lymph nodes. This is called the mediastinum.
Which regions control the rate of breathing?
Two regions in the hindbrain called the medulla oblongata and pons control the rate of breathing. –> called respiratory centres
How do the respiratory centres control the rate of breathing?
The pons and medulla oblongata respond to the concentration of carbon dioxide in the blood. When this concentration rises during a bout of activity, for example, nerve impulses are automatically sent to the diaphragm and rib muscles that increase the rate and the depth of breathing. Increasing the rate of breathing also increases the amount of oxygen in the blood to meet the needs of this increased activity.
What is the conductal zone of the respiratory system?
The part of the lungs that is distal from the trachea and before the alveoli i.e. the brochien and such
What is the function of the cilia on the cells that line the bronchial tree?
The beating of the cilia moves mucus lying on the surface of the epithelium of the conducting zone, and any contained dust, up out of the bronchial tree.
What term is applied to the volume of air that moves into the lungs while breathing at rest?
Tidal volume
What is the difference between external respiration and internal respiration?
External respiration: gas exchange between alveolar air and blood in pulmonary capillaries
Internal respiration: gas exchange between blood and tissues
How is the diaphragm innvervated?
The diaphragm is innervated by the phrenic nerves (not thoracic spinal nerves) which arise from the C3–C5 vertebrae. So, if the spinal cord is severed/damaged between these vertebrae, the organism won’t be able to breathe
The goal of respiration is to control the concentration of which substances dissolved in the blood?
oxygen, carbon dioxide and hydrogen ions
What constitutes the respiratory membrane?
The cells lining the alveoli and the capillaries and their fused basement membrane, along with the fluid (surfactant) lining the alveoli together are the membrane.
What is the “cribriform plate”?
The cribriform plate of the ethmoid bone has many foramina through which pass olfactory nerves that transmit sensory information from inhaled air to the olfactory bulbs.
Describe the structures in the bronchial tree, big to small
Brochii - secondary brochi - secondary bronchiole - terminal bronchiole - respiratory bronchiole - alveoli
Which structures constitute the “upper respiratory tract”?
The upper respiratory tract includes the larynx and superior structures.
Where are the conchae located?
The conchae are adjacent to the external nares (neusvleugels)
What passes through the foramina of the cribriform plate of the ethmoid bone?
nerve fibres associated with the sense of smell. The olfactory bulbs rest upon the cribriform plate and nerves from the bulbs descend through it to the top of the nasal cavity.
In what form is the majority of carbon dioxide that is generated by cellular respiration, transported to the lungs?
CO2 leaves cell as dissolved gas. About 7 % is transported in solution in plasma, 23 % bound to haemoglobin (HbCO 2) in rbc, while 70 % reacts
with water to form carbonic acid, which forms bicarbonate ions.
What happens when carbon dioxide levels in the blood decrease to below normal?
Carbon dioxide reacts with water to form carbonic acid and thence hydronium ions. So a decrease in CO 2 will decrease the concentration of hydronium ions (and pH will increase).
In a healthy person, which of these lung volumes should be the largest?
Vital capacity = expiratory reserve volume + tidal volume + inspiratory reserve capacity. So VC is the largest (RV is ~1.2 L).
With regard to lung ventilation, what does “dead space” refer to?
air in the conducting zone of the bronchial tree. Dead space refers to air that is inhaled into the airways but does
not reach the alveoli, hence is exhaled again without participating in gas
exchange.
What are the cells that produce surfactant called?
Type II pneumocytes produce the surface active agent (surfactant) that reduce the surface tension of the water that lines the alveoli.
