These are the main parts of the disposable camera and what their functions are:
This is the casing of the camera. The casing protects the inside of the camera and holds the parts of the camera in place. the casing also prevents light from coming in contact with the film.
This is the sutter if the camera. The shutter opens and closes between the lens and film when a picture is being taken. When it's release is clicked the curtain slides, opens and exposes the film.
This is the lens of the camera. The lens redirects the beams of light bouncing off the object so they come together and form an image.
This is the film of the camera. When the light is rejected off the objects in the camera's field of view, comes through and strikes the emulsion which is the part of the film that allows it to record images. This all happens when the shutter opens.
This is the flash circuit of the camera. The flash circuit makes a short flash of bright light when the shutter is released which causes the room to light up for a fraction of a second which helps with a lack of light inside.
This is the gas discharge tube of the camera. The gas discharge tube is to conduct an electrical current by moving one electrode to another. As the electrons move, they energize the xenon atoms, causing them to emit visible light photons, which is the flash.