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Jul 21, 2024 · Human skeleton, the internal skeleton that serves as a framework for the body. This framework consists of many individual bones and cartilages. There also are bands of fibrous connective tissue—the ligaments and the tendons—in intimate relationship with the parts of the skeleton.
- The Skeletal System Consists Of More Than Bones. When you look at the human skeleton the 206 bones and 32 teeth stand out. But look closer and you’ll see even more structures.
- The Adult Human Skeleton Is Made Up of 206 Bones. These bones provide structure and protection and facilitate motion. Bones articulate to form structures.
- The Skeleton Protects Vital Organs. The brain is surrounded by bones that form part of the skull. The heart and lungs are located within the thoracic cavity, and the vertebral column provides structure and protection for the spinal cord.
- Interactions Between the Skeleton, Muscles, and Nerves Move the Body. How does the skeleton move? Muscles throughout the human body are attached to bones.
Learn about the different types of skeletons in animals, such as exoskeletons, endoskeletons, pliant skeletons and hydrostatic skeletons. Find out how skeletons support, protect and enable movement and function in various organisms, from vertebrates to invertebrates.
The human skeleton is the internal framework of the human body. It is composed of around 270 bones at birth – this total decreases to around 206 bones by adulthood after some bones get fused together. [1]
- Overview
- Comparative study of skeletal systems
- Principal types of skeletal elements
skeleton, the supportive framework of an animal body. The skeleton of invertebrates, which may be either external or internal, is composed of a variety of hard nonbony substances. The more complex skeletal system of vertebrates is internal and is composed of several different types of tissues that are known collectively as connective tissues. This ...
In addition to its supportive function, the animal skeleton may provide protection, facilitate movement, and aid in certain sensory functions. Support of the body is achieved in many protozoans by a simple stiff, translucent, nonliving envelope called a pellicle. In nonmoving (sessile) coelenterates, such as coral, whose colonies attain great size, it is achieved by dead structures, both internal and external, which form supporting axes. In the many groups of animals that can move, it is achieved either by external structures known as exoskeletons or by internal structures known as endoskeletons. Many animals remain erect or in their normal resting positions by means of a hydrostatic skeleton—i.e., fluid pressure in a confined space.
The skeleton’s protective function alone may be provided by structures situated on the body surface—e.g., the lateral sclerites of centipedes and the shell (carapace) of crabs. These structures carry no muscle and form part of a protective surface armour. The scales of fish, the projecting spines of echinoderms (e.g., sea urchins), the minute needlelike structures (spicules) of sponges, and the tubes of hydroids, all raised from the body surface, are similary protective. The bones of the vertebrate skull protect the brain. In the more advanced vertebrates and invertebrates, many skeletal structures provide a rigid base for the insertion of muscles as well as providing protection.
The skeleton facilitates movement in a variety of ways, depending on the nature of the animal. The bones of vertebrates and the exoskeletal and endoskeletal units of the cuticle of arthropods (e.g., insects, spiders, crabs) support opposing sets of muscles (i.e., extensors and flexors). In other animal groups the hydrostatic skeleton provides such support.
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In a limited number of animals, the hard skeleton transmits vibrations that are sensed by the hearing mechanism. In some forms—e.g., bony fishes and fast-swimming squids—it aids in the formation of buoyancy mechanisms that enable the animal to adjust its specific gravity for traveling at different depths in the sea.
Certain types of skeletons usually characterize particular animal phyla, but there are a limited number of ways in which an animal can form its skeleton. Similar modes of skeleton formation have evolved independently in different groups to fulfill similar needs. The cartilaginous braincase of the octopus and the squid, which are invertebrates, has a microscopic structure similar to the cartilage of vertebrates. The calcareous (i.e., calcium-containing) internal skeleton of the echinoderms is simply constructed but is essentially not far different from the much more elaborate bones of vertebrates. Skeletal fibres of similar chemical composition occur in unrelated animal groups; for example, coiled shells of roughly similar chemical composition are present in gastropods (e.g., snails), brachiopods (e.g., lamp shells), and cephalopods (e.g., chambered nautilus). The mechanical properties of different skeletal types vary considerably according to the needs of animals of particular size ranges or habits (e.g., aquatic, terrestrial).
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Skeletal elements are of six principal types: hard structures, semirigid structures, connective tissue, hydrostatic structures, elastic structures, and buoyancy devices.
Aug 30, 2018 · Learn about the skeletal system, which consists of bones, cartilage, tendons, and ligaments. Find out how it supports, protects, moves, and produces blood cells in the body.
May 23, 2023 · Learn about the skeletal system, which consists of 206 bones and other structures that support, protect, and move the body. Find out how the skeletal system can be affected by various diseases and injuries, and what tests can diagnose them.
