Respiratory System Flashcards
(42 cards)
Explain why humans need a respiratory system
Humans have a low surface area to volume ratio and a high metabolic rate, which increases the demand for oxygen for aerobic respiration. The respiratory system facilitates efficient gas exchange to meet these demands.
Describe the process of ventilation
Ventilation is the exchange of air between the lungs and the surrounding environment. It involves inhalation, where air enters the lungs, and exhalation, where air exits the lungs.
State the function of the pulmonary arteries and pulmonary veins
Pulmonary arteries carry deoxygenated blood from the right ventricle to the lungs, while pulmonary veins carry oxygenated blood from the lungs to the left atrium.
Describe the role of ciliated epithelium in the respiratory system
Ciliated epithelium contains goblet cells that secrete mucus to trap debris and pathogens. The cilia waft the mucus upwards to the throat, where it can be swallowed, preventing harmful substances from reaching the lungs.
Explain the importance of cartilage in the trachea and bronchi
Cartilage provides structural support, keeping airways open during breathing. Its āCā shape in the trachea allows flexibility for the oesophagus to expand when swallowing food.
State the main function of bronchioles
Bronchioles transmit air to and from the alveoli and help regulate airflow through smooth muscle contraction and relaxation.
Describe the features of alveoli that make them efficient for gas exchange
Alveoli have a large surface area, thin walls made of squamous epithelial cells, and are surrounded by a dense capillary network. They are also moist and maintain a steep concentration gradient for efficient diffusion of gases.
Explain the role of surfactant in the alveoli
Surfactant reduces surface tension within the alveoli, preventing their walls from sticking together and collapsing, thereby maintaining open airways.
Describe the mechanism for inspiration
During inspiration, external intercostal muscles contract, pulling the rib cage up and out, and the diaphragm flattens. This increases the volume of the thoracic cavity, decreases pressure in the lungs, and draws air in.
Explain how the concentration gradient is maintained during gas exchange in the lungs
The concentration gradient is maintained by constant blood flow removing oxygenated blood and bringing deoxygenated blood, along with regular ventilation replacing air in the alveoli.
state the role of elastic fibers in the respiratory system
Elastic fibers allow the airways to stretch and recoil during breathing, ensuring that the airways return to their original shape after stretching.
explain how changes in CO2 levels affect breathing rate
Increased CO2 lowers blood pH, which is detected by chemoreceptors in the carotid artery and aorta. These send signals to the ventilation center, which adjusts the rate of breathing to restore pH balance.
Describe the role of the pleural membranes during ventilation
The pleural membranes and pleural fluid create surface tension, ensuring the lungs move with the thoracic cavity during breathing. This allows changes in chest cavity volume to affect lung volume directly.
Explain why the trachea has C-shaped cartilage rings instead of complete rings
The C-shaped cartilage provides structural support to keep the airway open while allowing flexibility for the oesophagus to expand during swallowing.
state the function of smooth muscle in the respiratory system
Smooth muscle controls airflow by contracting to narrow airways and relaxing to widen them. This helps regulate the flow of air to and from the alveoli.
describe how oxygen is transported in the blood
Oxygen diffuses into red blood cells in the alveoli and binds to haemoglobin, forming oxyhaemoglobin. It is transported to tissues where it diffuses into cells for respiration.
explain the role of the diaphragm in ventilation
During inspiration, the diaphragm contracts and flattens, increasing the volume of the thoracic cavity and reducing lung pressure, drawing air in. During expiration, it relaxes and returns to a dome shape, reducing thoracic volume and forcing air out.
state the structural differences between bronchi and bronchioles
Bronchi have cartilage rings, ciliated epithelium, and glandular tissue, while bronchioles lack cartilage rings and are smaller in diameter, with smooth muscle and elastic fibers instead.
describe the role of the nasal cavity in respiration
The nasal cavity warms, moistens, and filters incoming air. Its blood supply warms the air, mucus traps particles, and hairs filter out debris.
explain the significance of thin alveolar walls in gas exchange
Thin alveolar walls, made of squamous epithelium, create a short diffusion pathway, enabling efficient gas exchange between the alveoli and capillaries.
State the differences in oxygen and carbon dioxide concentrations between alveoli and blood during gas exchange
Oxygen concentration is higher in alveoli and lower in blood, causing oxygen to diffuse into the blood. Carbon dioxide concentration is higher in blood and lower in alveoli, causing carbon dioxide to diffuse into the alveoli.
describe how moisture in the alveoli aids gas exchange
Moisture in the alveoli dissolves gases, making it easier for oxygen to diffuse into the blood and for carbon dioxide to diffuse into the alveoli.
explain the role of elastic fibers in alveoli
Elastic fibers allow alveoli to stretch during inspiration and recoil during expiration, aiding efficient air movement in and out of the lungs.
state the function of chemoreceptors in controlling ventilation
Chemoreceptors detect changes in blood pH caused by CO2 levels. They send signals to the ventilation center to adjust breathing rate and depth to restore pH balance.
