respiratory system

acilitates the intake of oxygen and the removal of carbon dioxide

The passageways leading to the lungs serve to purify, warm, and humidify the incoming air

Houses receptors for the sense of smell

Ventilation involving the inhalation and exhalation of air, moving oxygen and carbon dioxide between the atmosphere and the lungs

the circulatory system transports oxygen from the lungs to body tissues and carries carbon dioxide back from tissues to the lungs.

oxygen diffuses out of capillaries into cells (for cellular respiration in the mitochondria), while carbon dioxide diffuses out of cells into capillaries.

(e.g., amoeba) and simple two-layer animals like Hydra (with a gastrovascular cavity) rely on direct diffusion across their cell membranes because they are thin or small enough (0.15 to 1.5).

use water flow driven by choanocytes through pores (porocytes) to an osculum

utilize a gastrovascular cavity or pharynx for internal/external exchange.

Found in animals like fish, annelid parapodia, and crustaceans.

In fish gills, water flows across the lamellae in the opposite direction to blood flow through the capillaries. This maintains a concentration gradient across the entire length of the capillary, maximizing oxygen uptake from water.

use a network of branching tubes called tracheae that open to the outside through pores called spiracles.

Air travels through tracheae into fluid-filled _____, which deliver oxygen directly to muscle cells.

Spiders possess internal stacked plate-like structures housed in an internal chamber that facilitate gas exchange.

feature lungs coupled with anterior and posterior air sacs, allowing a continuous one-way flow of air rich in oxygen through the lungs during both inhalation and exhalation.

Contains the vocal cords and is protected by the epiglottis, which acts as a lid to keep food out of the airway.

The opening between vocal cords is the

The inner lining of the respiratory tract features ______ (cilia) that sweep mucus and trapped debris upward away from the lungs.

produce surfactant to reduce surface tension and keep alveoli from collapsing.

patrol and engulf foreign debris or pathogens

allow air pressure to equalize between adjacent alveoli.

The diaphragm contracts and moves inferiorly (flattens); External intercostal muscles contract, elevating the ribs; Thoracic volume increases, decreasing internal pressure, which forces air (gases) into the lungs.

The diaphragm relaxes and moves superiorly; External intercostal muscles relax, depressing the rib cage; Thoracic volume decreases, increasing internal pressure and forcing air out of the lungs.

Controlled by respiratory centers in the brain (medulla oblongata and pons); Triggered primarily by an increase of carbon dioxide in the blood (acting directly) and signals from oxygen sensors (located in the aortic arch) indicating an oxygen decrease; Signals travel down via the phrenic nerves (to the diaphragm) and intercostal nerves (to intercostal muscles).

Oxygen diffuses from alveolar spaces into pulmonary capillaries; carbon dioxide diffuses in reverse

Oxygen unloads from hemoglobin to tissue cells