Ch 14 Breathing and exchange of gas Flashcards
How does the mechanism of breathing vary among animals?
The mechanism of breathing varies based on their habitats and levels of organization.
How do lower invertebrates like sponges, coelenterates and flatworms respire?
They exchange oxygen (O₂) with carbon dioxide (CO₂) by simple diffusion over their entire body surface.
What structure do earthworms use for respiration?
Moist cuticle
How do insects transport atmospheric air within their bodies?
Insects use a network of tubes called tracheal tubes for respiration.
What are gills and which organisms use them?
Gills are vascularized structures used for branchial respiration, mainly by aquatic arthropods and molluscs.
What is pulmonary respiration, and who uses it?
Pulmonary respiration involves vascularised bags called lungs, used by terrestrial animals like reptiles, birds, and mammals.
Which vertebrates use gills for respiration?
Fishes use gills for respiration.
How do amphibians like frogs respire?
Frogs respire through their moist skin (cutaneous respiration)
What type of respiration is observed in terrestrial vertebrates?
Terrestrial vertebrates primarily respire through lungs.
What are the external openings of the human respiratory system called?
The external openings are called nostrils, located above the upper lips.
What is the function of the nasal chamber?
The nasal
chamber opens into the pharynx, a portion of which is the common
passage for food and air.
What is the pharynx, and what is its role?
The pharynx is a common passage for food and air.
What is the larynx, and why is it called the “sound box”?
The larynx is a cartilaginous box responsible for sound production, earning it the name “sound box.”
What prevents food from entering the larynx during swallowing?
The epiglottis, a thin elastic cartilaginous flap, covers the glottis to prevent food entry.
What is the trachea, and where does it divide?
The trachea is a straight tube extending to the mid-thoracic cavity and divides into the right and left primary bronchi at the 5th thoracic vertebra.
How are bronchi further subdivided?
Primary bronchi divide into secondary and tertiary bronchi, which further branch into bronchioles and terminal bronchioles.
What supports the trachea and bronchi?
Incomplete cartilaginous rings support the trachea, primary, secondary, and tertiary bronchi, and initial bronchioles.
What are alveoli?
Alveoli are thin, irregular-walled, vascularized bag-like structures where gas exchange occurs.
What is the double-layered membrane covering the lungs called?
It is called the pleura, with pleural fluid between the layers to reduce friction on the lung surface.
What is the difference between the conducting and respiratory parts of the respiratory system? (PYQ 2022)
The conducting part (from external nostrils to terminal bronchioles)
1. Transports the atmospheric air to the alveoli
2. Clears it from foreign particles
3. Humidifies
4. Brings the air to body temperature.
Exchange part is the site of actual diffusion of O2 and CO2
between blood and atmospheric air.
What constitutes the thoracic chamber?
The thoracic chamber is formed dorsally by the vertebral column, ventrally by the sternum, laterally by the ribs, and on the lower side by the dome-shaped diaphragm.
Why is the thoracic chamber’s air-tight nature important?
It allows changes in thoracic volume to be reflected in lung volume, essential for breathing.
(see this question)
What are the main steps involved in respiration?
- Breathing or pulmonary ventilation by which atmospheric air is drawn in and CO2 rich alveolar air is released out.
- Diffusion of gases (O2 and CO2 ) across the alveolar membrane.
- Transport of gases by the blood.
- Diffusion of O2 and CO2 between blood and tissues.
- Utilization of O2 by the cells for catabolic reactions and resultant release of CO2 (cellular respiration as dealt in the Chapter 12).
What is the role of the epiglottis?
The epiglottis prevents food from entering the larynx during swallowing by covering the glottis.