Answer:
1. tiny sacs within the lungs which increase the surface available for gas exchange (Answer: alveoli)
Explanation: The alveoli are the endpoint of the respiratory system, in which thin walls Oxigen and Carbon Dioxide are diffused between the atmosphere and the bloodstream.
2. a digestive enzyme that breaks down starches and glycogen into sugars (Answer: amylase)
Explanation: The amylase enzyme is produced by the salivary glands and the pancreas. It catalyzes the hydrolysis of starch into more simple forms of sugars (disaccharides and trisaccharides, for example).
3. the two thin-walled chambers that receive blood into the heart from the veins (Answer: atria).
Explanation: In mammals, birds and some reptilia, the heart is a tetracameral organ (two atria, which receives the blood from the body, and two ventricles, that pumps the blood through the body systems).
4. the two tubes into which the trachea divide to go into each lung (Answer: bronchi).
Explanation: The trachea divides into two bronchi to enter the lungs through the hilum (the root of the lungs), where it successively divided and ends up forming the alveoli.
5. a tiny vessel through which diffusion takes place between the blood and the body tissues (Answer: capillary)
Explanation: The capillary are small blood vessels wich walls are of a one endothelial cell thick, that facilitates gas diffusion between the bloodstream and surrounding tissue.
6. a mass of nerve tissue not part of the brain (Answer: ganglia).
Explanation: A ganglion is a neuronal cell cluster located generally outside the central nervous system. There are two types of ganglia: Dorsal root ganglion and autonomic ganglion.
