![]() To date, nearly 2 million species of invertebrates have been identified. Nevertheless, invertebrates are also found in a vast range of habitats, from forests and deserts, to caves and seabed mud. ![]() The highly developed nervous system and internal skeletons of vertebrates allow them to adapt to land, sea, and air. This includes animals who move in search of food.īoth types of animals live in a variety of habitats, but vertebrates can essentially suit themselves in all habitats easily. Invertebrates have two basic body plans: one is the radial symmetry plan (a circular shape arranged around a central mouth, similar to the way spokes radiate out from the hub of a wheel), which includes animals who spend their adult lives fastened in one place and the bilateral symmetry plan (right and left halves that mirror each other and typically have a definite front and back end). While most vertebrates can move and are heterotrophic (i.e., cannot make their own food), some invertebrates may be able to make their own food.ĭue to lack of a supportive system, a majority of invertebrates are small. Vertebrates are divided into two groups: animals without jaws ( Agnatha) and animals with jaws ( Gnathostomata). Vertebrates have well-developed sensory organs, a respiratory system with either gills or lungs, and a bilateral symmetry with an advanced nervous system that further distinguishes them from invertebrates. A nerve cord is enclosed by vertebrae - individual bones that make up a vertebrate's spine. Invertebrates have no backbone, while vertebrates have a well-developed internal skeleton of cartilage and bone and a highly developed brain that is enclosed by a skull. Red marrow functions in the formation of red blood cells, white blood cells and blood platelets.Vertebrates have a skeletal structure with a spinal column or backbone. In adults, red marrow is limited to the spongy bone in the skull, ribs, sternum, clavicles, vertebrae and pelvis. With age, it is largely replaced by yellow marrow for fat storage. In infants, red marrow is found in the bone cavities. Hematopoiesis, the formation of blood cells, mostly takes place in the red marrow of the bones. The dynamic process of releasing and storing calcium goes on almost continuously. When blood calcium levels are increased, the excess calcium is stored in the bone matrix. When blood calcium levels decrease below normal, calcium is released from the bones so that there will be an adequate supply for metabolic needs. The intercellular matrix of bone contains large amounts of calcium salts, the most important being calcium phosphate. ![]() Vertebrae surround and protect the spinal cord and bones of the rib cage help protect the heart and lungs of the thorax.īones work together with muscles as simple mechanical lever systems to produce body movement.īones contain more calcium than any other organ. The fused bones of the cranium surround the brain to make it less vulnerable to injury. The skeleton also protects the soft body parts. The large bones of the lower limbs support the trunk when standing. The skeleton supports the body against the pull of gravity. They contain active tissues that consume nutrients, require a blood supply and change shape or remodel in response to variations in mechanical stress.īones provide a rigid framework, known as the skeleton, that support and protect the soft organs of the body. The living bones in our bodies use oxygen and give off waste products in metabolism. The human skeletal system consists of bones, cartilage, ligaments and tendons and accounts for about 20 percent of the body weight. They rely on a sturdy internal frame that is centered on a prominent spine. Humans are vertebrates, animals having a vertabral column or backbone. Acknowledgements Introduction to the Skeletal System
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |