Good to talk to you earlier! We can answer your tongue question more here. The toungue is made of a set of muscles so that we can move and sense things by touch and taste. It has multiple muscles that anchor it in place from the base of the tongue (extrinsic muscles), letting us move it up and down, left and right, and front to back. Then there are another set of muscles (intrinsic) within the toungue that let us make it bigger and softer, or smaller and tenser, and generally to control movement within the toungue – like if you roll the tip back.
So the main part of the tongue is muscle and on the lining are taste cells and sense nerves. There are special cells that have special hairs protruding from them that interact with the food and our siliva. This sets off a sensory and chemical reaction that the taste cell then communicates to nerve cells that send the message of taste to your brain. At which point we comment “yum!”.
I work on parasites and there is only particular fish parasite infamous for it’s tounge-related behaviour. It’s called Cymothoa exigua, basically a small sea insect. It swims into the gills of fish and eventually lodges at the tounge base muscles. It starts eating the tounge, and gradually grows to replace it. In fact, it replaces the entire tounge! And of course we all need our tounge for taste/swallowing/sensing, so the fish now use the parasite sea insect as their tounge. See below for a picture of it!
The interesting thing about the tongue is that is is the only muscle in the body that is only attached at one end. All the other muscles are attached to something at both ends and so allow us to move. The average human tongue is about 10cm long.
The little round things on your tongue are your taste buds. That whole thing about you tasting different things in different areas is nonsense I’m afraid. There’s an easy way to see you taste buds: eat a lolly that changes the colour of your tongue. The skin on your tongue will change colour but the the taste buds will still be pink.