### body part | organ:

Gill
* Most gills act as lungs.
* Most gills have appearances
  - functions
  - serve for respiration
* Some gill slits have exchanges
  - gas exchanges
  - gills absorb oxygen
* Some gills have fins
  - overall shapes
  - surfaces
* absorb dissolved gasses from water.
* adapts to a wide range of conditions.
* also begin to develop
  - excretory in some species
  - give off carbon dioxide
* appear redder than normal, and the gill covers, stand out so that the gills are visible.
* are also common in certain land animals, such as spiders and scorpions
  - average sized, with a lot of little ones
  - body parts
  - both off of the body and off of limbs
  - chracteristic of many aquatic animals, include fish, aquatic insects, and mollusks
  - delicate and full of blood vessels
  - designed to function in water, lungs in air
  - feathery organs full of blood vessels
  - highly branched and folded to provide a large surface area for gas exchange
  - like a filter they keep the water in and keep the germs out
  - located posterior to the heart
  - made of filaments which help increase surface area for oxygen exchange
  - more efficient with greater surface area
  - much more complex than just a slit in the cheeks of a fish
  - normally low in carbon dioxide and high in oxygen
  - only one pair
  - out-foldings of the body surface that are suspended in the water
  - paired, filibranchs and used for respiration as well as filter feeding
  - part of cups
  - present on either side of the head and are supplied by rich blood vessels
  - present, at least during some early stages of development
* are respiratory organs in most animals that breathe under water
  - that absorb oxygen from water as it flows over the gill surface
* are retained for a few days after hatching
  - throughout life
  - solid objects
* are the exchange point
  - respiratory organs for fishes
  - therefore very efficient at absorbing oxygen from water
  - tissues which consist of threadlike protein structures called filaments
  - used to exchange oxygen and carbon dioxide in respiration
* assist the ones that reside in water.
* can collect dissolved oxygen from the water and release carbon dioxide.
* consist of thin sheets of tissue containing blood vessels.
* do the same job for fish that lungs do for many other kinds of animals, including humans.
* expel water.
* extract oxygen from surrounding water
  - the oxygen from the water, and they move by jet propulsion
* fall off within a couple days of the birth.
* function to digest food
  - exchange gases betweeen a fish and the water
* greatly increase the surface area for gas exchange.
* have a lot of blood vessels
  - less surface area than lungs
* help a fish breathe.
* includes corpi
  - lobes
* is an unit
* make fishes vulnerable to loss of heat and loss of water
  - jaws make ears make room for a big brain
* obtain oxygen from water.
* occur on or close to the bases of the thoracic appendages.
* perform the gas exchange between the water and the fish's blood.
* produce the basidiospores of A. bisporus
  - spore-bearing structures known as basidia
* sit under the operculum.
* slits allow water to pass into the chambers, which helps break down the food even more
  - are, at some stage of life, found in all chordates
  - develop into gills in fish and into ears of mammals
  - form gills in fish
* slits, eyes and mouths come into focus.
* take dissolved oxygen from water as the water flows over the surface of the gill
  - oxygen out of the water and let water carry away carbon dioxide
* work because oxygen very small molecule
  - better when there is more oxygen in the surrounding water
+ Guppy: Ray-finned fish
  * Guppies have a tongue, teeth, a pharynx, gill slits, an esophagus, a stomach, intestines, and an anal opening. Digestion begins in the mouth. First, the food is mashed up into small pieces by the teeth. Then, the food travels down the pharynx. On either side of the pharynx, there are gill slits. Gill slits allow water to pass into the chambers, which helps break down the food even more. The food must pass through the esophagus in order to enter the stomach. Inside the stomach, the intestines move food so it can be digested quickly. The remains of the food is then sent out through the anal opening.