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Photo shows a human skeleton riding a bucking horse skeleton.
The skeletons of humans and horses are examples of endoskeletons. (credit: Ross Murphy)

The human skeleton is an endoskeleton that consists of 206 bones in the adult. It has five main functions: providing support to the body, storing minerals and lipids, producing blood cells, protecting internal organs, and allowing for movement. The skeletal system in vertebrates is divided into the axial skeleton (which consists of the skull, vertebral column, and rib cage), and the appendicular skeleton (which consists of the shoulders, limb bones, the pectoral girdle, and the pelvic girdle).

Visit the interactive body site to build a virtual skeleton: select "skeleton" and click through the activity to place each bone.

Human axial skeleton

The axial skeleton    forms the central axis of the body and includes the bones of the skull, ossicles of the middle ear, hyoid bone of the throat, vertebral column, and the thoracic cage (ribcage) ( [link] ). The function of the axial skeleton is to provide support and protection for the brain, the spinal cord, and the organs in the ventral body cavity. It provides a surface for the attachment of muscles that move the head, neck, and trunk, performs respiratory movements, and stabilizes parts of the appendicular skeleton.

On a human skeleton, the parts of the axial skeleton are highlighted.
The axial skeleton consists of the bones of the skull, ossicles of the middle ear, hyoid bone, vertebral column, and rib cage. (credit: modification of work by Mariana Ruiz Villareal)

The skull

The bones of the skull    support the structures of the face and protect the brain. The skull consists of 22 bones, which are divided into two categories: cranial bones and facial bones. The cranial bones are eight bones that form the cranial cavity, which encloses the brain and serves as an attachment site for the muscles of the head and neck. The eight cranial bones are the frontal bone, two parietal bones, two temporal bones, occipital bone, sphenoid bone, and the ethmoid bone. Although the bones developed separately in the embryo and fetus, in the adult, they are tightly fused with connective tissue and adjoining bones do not move ( [link] ).

The eight cranial bones of the skull are shown.
The bones of the skull support the structures of the face and protect the brain. (credit: modification of work by Mariana Ruiz Villareal)

The auditory ossicles of the middle ear transmit sounds from the air as vibrations to the fluid-filled cochlea. The auditory ossicles consist of six bones: two malleus bones, two incus bones, and two stapes on each side. These are the smallest bones in the body and are unique to mammals.

Fourteen facial bones form the face, provide cavities for the sense organs (eyes, mouth, and nose), protect the entrances to the digestive and respiratory tracts, and serve as attachment points for facial muscles. The 14 facial bones are the nasal bones, the maxillary bones, zygomatic bones, palatine, vomer, lacrimal bones, the inferior nasal conchae, and the mandible. All of these bones occur in pairs except for the mandible and the vomer ( [link] ).

Illustration shows a front-end view of a skull. The frontal bone is the prominent bone that makes up most of the top of the skull. The parietal bone sphenoid bones make up the side of the skull. Two nasal bones make up the bridge of the nose. The zygomatic bone is the cheek bone. The vomer is a single bone in the middle of the nose. The maxilla makes up the upper jaw, and the mandible is the lower jaw. The lacrimal is a bone on the inner center of they eye. The nasal conchae are bones inside the nose.
The cranial bones, including the frontal, parietal, and sphenoid bones, cover the top of the head. The facial bones of the skull form the face and provide cavities for the eyes, nose, and mouth.

Questions & Answers

what are structure of the cell
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what did Darwin say about evolution
Hope Reply
effect of planning beans of using fertilizer
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what do we mean by transgenic organisms?
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They are the regions of the pancreas that contains the endocrine cell
Iyadi
is the studly of life
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Asunta Reply
is the study of living organism and their interection with one another and their environment.
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the top layer of the earth in which plant's, tree's
Ahmad
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Asunta
function of cell wall
Nthati Reply
function of cell wall
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To protect the cell from bursting
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to protect the cell from bursting
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to protect all other internal components of the cell
Olaoye
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sex cells
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hlo
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procryotic cell and some eucaryotic cell
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hello guys what's the difference between prokaryotes and eukaryotes
Nwachukwu Reply
hlo what are the applications of biology?
Namawejje
eukaryotic cells have DNA in their nucleus while prokaryotic cells have their DNA present freely in their cytoplasm.
FADILAT
deviation from mendelian
Ogali Reply
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Ogali
a lethal allele is an allele that can cause poor development or even death of an organism
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Source:  OpenStax, Biology. OpenStax CNX. Feb 29, 2016 Download for free at http://cnx.org/content/col11448/1.10
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