Anatomy of Earthworm, Crab, Squid, and Frog

prostomium

Lobe above the mouth that functions as a sensory device to "feel" their way through the soil

Mouth

Opening that takes in material from the surrounding environment

Setae

Small bristles that stick outwards to grip to the surround surface and provide traction

Clitellum

A swelling located around 1/3 of the way down the earthworm and contains materials required for reproduction

Anus

Opening that extrudes waste material

Pseudohearts/aortic arches

Help pump blood through the blood vessels

Dorsal blood vessel

Collects blood from the body and pushes it into the Pseudohearts

Ventral blood vessel

Distributes blood from the Pseudohearts to the rest of the body

Pharynx

Muscular organ that is responsible for swallowing and forcing material through the digestive system

esophagus

Narrow tube that transports material from the pharynx to the crop

crop

Serves as a temporary storage organ for material

gizzard

Organ filled with gravel and sand that grinds food by contracting

Intestine/stomach

Organ where uptake of nutrients occurs through secreted enzymes

Seminal receptacles

Stores sperm

Seminal vesicles

Produces sperm

Typhlosole

Flaps within the intestine that increases surface area for absorption

Carapace

The hard shell that covers and protects the body of the crab

Cephalothorax

The body of the crab that contains both the head and thorax

Pereopods

The five pairs of appendages that vary in function from providing locomotion, grabbing objects/prey, and swimming through the water

Chelipeds

The pair of appendages located closest to the anterior end of the body; they end in claws which allow the crab to handle objects

Dactyl

The movable finger of the claw that allows the crab to grab and crush objects

Manus (aka propodus)

The immovable portion of the claw serves as the base of the claw that objects are crushed against

Maxillipeds

Outer appendages that surround the mouth help shovel food from the claws into the mouth

Mandibles

Jaws of the mouth that help to crush food

Apron/abdomen

Located on the lower part of the body, serves as a protective layer for the reproductive organs

Male pleopods

Located under the front of the abdomen and are used to transfer spermatophores

Female pleopods (Swimmerets)

Used to excrete stored sperm into a mass of eggs known as a sponge

Gonopores

Genital pores on the female that accept spermatophores from the pale pelopods

Gills

Located under the shell and utilized for respiration

Heart

Located in the body cavity and pumps hemolymph through the body

Ostia

Openings located within the body that have valves to prevent backflow of hemolymph

Stomach

Contains hard plates that aid in breaking down food for further digestion

Digestive glands/Hepatopancreas

Produces digestive enzymes and filters hemolymph

Testes and ovaries

Areas where sperm is produced and eggs are stored

Gill cleaners

Ensure water flow over the gills by removing debris and other organisms

Brain

Location of sensory processing and actions for the crab

Compound eye

Located on stalks that can extend out from the main body of the crab and provide a wide range of vision

Mantle

Outer body that protects and houses the internal organs

Fins

Used for steering the squid and for forward/backward movement

Chromatophores

Allow the squid to change color for camouflage and avoiding predators

Siphon

Main structure responsible for movement through expelling large amounts of water in a short amount of time, creating a form of underwater jet propulsion.

Eyes/lens

Allow for vision underwater

Arms

Shorter tentacles that are used to hold and manipulate objects

Feeding Tentacles

Longer tentacles that are equipped with suckers in order to catch and capture prey

Buccal mass/mouth

Point of entry for food into the digestive system and helps to physically breakdown food

Ctenidia (gills)

Exchanges oxygen from water into the blood in order to oxygenate it

Branchial heart

Pumps blood to the gills to be oxygenated

System heart

Pumps oxygenated blood to the rest of the body

Reproductive Organs

Produce sperm or egg depending on the gender of the squid

Siphon retractor muscles

Allows control of the direction in which the water jet is pointed

caecum

Absorbs nutrients from food before passing it along to the intestine

stomach

Structure that holds food for digestion and helps break down food through digestive enzymes

Esophagus

Small tube that connects the mouth to the stomach and allows food to pass through

Ink sac

Gland that produces ink for defensive purposes

pen

Hard Feather shaped structure that runs along the mantle of the squid

Maxillary Teeth

Row of teeth located on the upper jaw that help to grip prey

Vomerine Teeth

Set of teeth located at the tip of the mouth that help to grip prey

Tongue

Help to catch prey by rapidly flicking out the posterior sticky end

Nares

Openings for air that extends from the exterior of the frog to the interior of the mouth

Eustachian Tubes

Equalize pressure in the inner ear when the frog is under water

Glottis

Slit in the neck that allows air to travel from the mouth to the lungs

Thumb pad

Enlarged thumb that helps male frogs to latch onto and hold down female frogs when mating

Tympanic Membrane

Transmit acoustic vibrations from the external environment to the inner ear

Fat bodies

Allows for storage of fats that store energy and provide buoyancy in water

Liver

Produces bile for digestion

Gallbladder

Stores excess bile until it is released into the small intestine

Stomach

Breaks down food into smaller chunks through the contraction of muscles

Small Intestine

Food is digested and nutrients are absorbed

Large Intestine/Colon

Absorption of water and ions

Cloaca

Opening that allows for secretion of waste and reproductive cells

Lungs

Site of gas exchange where blood is oxygenated and carbon dioxide is expelled

Spleen

Filters out old red blood cells and replaces them with new red blood cells

Pancreas

Secrete digestive enzymes into the small intestine

Kidneys

Filters waste out of the blood stream and produces urine

Heart

Pumps deoxygenated blood to the lungs and oxygenated blood to the rest of the body