Animal anatomy

The mesonephros (Greek: middle kidney) is one of three excretory organs that develop in vertebrates.

Standard anatomical terms of location deal unambiguously with the anatomy of animals, including humans.

Autotomy (from the Greek auto- "self-" and tome "severing") or self amputation is the behaviour whereby an animal sheds or discards one or more of its own appendages, usually as a self-defense mechanism to elude a predator's grasp or to distract the predator and thereby allow escape.

Fins are usually the most distinctive features of a fish.

The anus (from Latin anus, meaning "ring, anus", which is from Proto-Indo-European *h₁eh₂no-, meaning "ring") is an opening at the opposite end of an animal's digestive tract from the mouth.

The blood–brain barrier (BBB) is a highly selective permeability barrier that separates the circulating blood from the brain extracellular fluid in the central nervous system (CNS).

In animal anatomy, a cloaca /kloʊˈeɪkə/ kloh-AY-kə (plural cloacae /kloʊˈeɪsiː/ kloh-AY-see or /kloʊˈeɪkiː/ kloh-AY-kee) is the posterior orifice that serves as the only opening for the digestive, reproductive, and urinary tracts (if present) of certain animals, opening at the vent.

An egg is the organic vessel containing the zygote in which an animal embryo develops until it can survive on its own, at which point the animal hatches.

The lymphatic system is part of the circulatory system and a vital part of the immune system, comprising a network of lymphatic vessels that carry a clear fluid called lymph (from Latin, lympha meaning water) directionally towards the heart.

Muscle is a soft tissue found in most animals.

The skeleton (from Greek σκελετός, skeletós "dried up") is the body part that forms the supporting structure of an organism.

In zoology, a tentacle is a flexible, mobile, elongated organ present in some species of animals, most of them invertebrates.

A tooth (plural teeth) is a small, calcified, whitish structure found in the jaws (or mouths) of many vertebrates and used to break down food.

A horn is a permanent pointed projection on the head of various animals consisting of a covering of keratin and other proteins surrounding a core of live bone.

The pharynx (plural: pharynges) is the part of the throat that is behind the mouth and nasal cavity and above the oesophagus and the larynx, or the tubes going down to the stomach and the lungs.

The vocal tract is the cavity in human beings and in animals where sound that is produced at the sound source (larynx in mammals; syrinx in birds) is filtered.

In human anatomy, the acromion (from Greek: akros, "highest", ōmos, "shoulder", plural: acromia) is a bony process on the scapula (shoulder blade).

In humans and most mammals, the chorion is one of the membranes that exist during pregnancy between the developing fetus and mother (the fetal membranes).

A gonopore, sometimes called a gonadopore, is a genital pore in many invertebrates.

The neck is the part of the body, on many terrestrial or secondarily aquatic vertebrates, that distinguishes the head from the torso or trunk.

In vertebrate anatomy, ribs (Latin: costae) are the long curved bones which form the rib cage.

Sexual dimorphism is the condition where the two sexes of the same species exhibit different characteristics beyond the differences in their sexual organs.

The philtrum (Latin: philtrum, Greek: φίλτρον philtron), or medial cleft, is a vertical groove in the middle area of the upper lip, common to many mammals, extending in humans from the nasal septum to the procheilon.

In arthropod and vertebrate anatomy, the vertex (or cranial vertex) refers to the upper surface of the head.

In animal anatomy, the notochord is a flexible rod made out of a material similar to cartilage.

An otolith (οτο-, oto-, ear + λιθος, lithos, a stone), also called statoconium or otoconium or statolith, is a structure in the saccule or utricle of the inner ear, specifically in the vestibular labyrinth of vertebrates.

Osteosclerosis is a type of osteopetrosis that involves abnormal hardening of bone and an elevation in bone density.

The coelom (/ˈsiːləm/ SEE-ləm, plural coeloms or coelomata /siːˈloʊmətə/ see-LOH-mə-tə) (Greek koilōma, hollow, cavity) refers to the main body cavity in most multicellular animals and is positioned inside the body to surround and contain the digestive tract and other organs.

An eyespot (sometimes ocellus) is an eye-like marking.

The umbilical plane is the transverse plane passing through the umbilicus.

A cuticle /ˈkjuːtɪkəl/, or cuticula, is any of a variety of tough but flexible, non-mineral outer coverings of an organism, or parts of an organism, that provide protection.

The articular capsule of the knee joint (commonly referred to as capsular ligament) is wide and lax; thin in front and at the side; and contains the patella ("knee cap"), ligaments, menisci, and bursae.

The medial compartment of thigh is one of the fascial compartments of the leg and contains the hip adductor muscles and the gracilis muscle.

A carapace is a dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises.

A body cavity is any fluid-filled space in a multicellular organism other than those of vessels (such as blood vessels and lymph vessels).

In anatomy, a suture is a fairly rigid joint between two or more hard elements of an organism, with or without significant overlap of the elements.