External Respiration takes place in the Trachea. When oxygen and co2 "switch" its where they connect and making this external respiration!
I hope this helps you!
Paneth cells are specialized immune cells that are found in the gastrointestinal tract. Paneth cells act as anti-microbial defence for our bodies. It is found in the crypts of the intestine. It is also responsible for the renewal of epithelial layer cells which keep bacteria from entering the intestines.
Octopus and squid have little suction cups on their tentacles. It helps with sticking onto food (so it doesn't get away) and also helps with sticking into things. If it wanted to camouflage into some rocks, it can use its tentacles to cling to to the rock.
Tentacles can also grab and carry things. Scientists have made tests where they would put a clam in a jar with the lid screwed on. The octopus would grab onto the jar and use its tentacles to twist the lid off.
Without tentacles, octopuses and squids would be pretty helpless and probably couldn't survive in the deep ocean.
The thyroid is a butterfly-shaped gland that lies in front of the windpipe (trachea), just below the voice box. The parathyroid glands are four tiny glands located behind the thyroid gland. The parathyroid glands produce a substance (parathyroid hormone) that helps control the amount of calcium in the blood.
