Skeletal System 1. Skeletal System. First Name Last Name. Biology, Period 4. Mr. Lord

Transcription

1 Skeletal System 1 Skeletal System First Name Last Name Biology, Period 4 Mr. Lord May 20, 2011

2 Skeletal System 2 Abstract The skeletal system is what supports, protects, and helps to move the human body. The bones that make up the skeleton are complex, and very strong. Joints, ligaments, tendons and cartilage all assist the bones of the skeleton in carrying out the tasks it needs to, by attaching either muscle to bone, or bone to bone. These attachments help to flex or extend muscles in the body. The human skeleton can be broken up into two main sections; the Axial Skeleton and the Appendicular Skeleton. The Axial Skeleton consists of 80 bones. This includes all the bones of skull, mandible, ribs, and the vertebral column. The Appendicular Skeleton consists of about 126 bones, including those of the shoulders, upper limbs (arm, forearm, hand, and wrist), the pelvic girdle, and the lower limbs (thigh, leg, ankle, foot). This part of the skeleton helps the human body to move and manage objects. Along with being beneficial to the human species, various diseases or conditions related to bones can cause much pain and difficulty. Some of these are Osteoporosis, Arthritis, Spina Bifida, and Scoliosis. Although both males and females have skeletons, they are not completely the same. There are many gender-based differences of the human skeleton.

3 Skeletal System 3 Introduction Bones are what make up the human skeleton. Whether the bones are fused or just individual bones, they are what serve as the scaffolding for our bodies. This scaffold supports the organs, anchors the muscles, and protects the organs of our bodies (Reynolds). Our skeleton protects organs such as the brain, lungs, and heart; all things we need to live. Framework is provided by the skeleton to support the body and help maintain its shape. The joints between our bones is what permits movement. Different joints allow wider ranges of movement, such as the ball and socket joint, rather than the pivot joint. Movement of our skeleton is powered by various skeletal muscles which are attached to different sites of various bones. Two main sections make up the human skeleton: the axial skeleton, and the appendicular skeleton. The axial skeleton, which is formed by the vertebral column, the rib cage, and the skull, consists of eighty bones, while the appendicular skeleton consists of 126 bones. What Bones are Made of, and Development of Bones Bones are not just solid and the same throughout; there are different layers allowing bones to be as strong as they are. Hard or compact bone is what typically makes up the outer layer of bones, and is very dense, strong and tough. A layer of spongy bone is next, which is lighter and slightly flexible, almost like honeycomb. Inside both the compact and spongy layers comes a jelly-like substance called bone marrow. This is where new cells are continuously being made for blood. At birth, newborns have over 300 bones, which over time fuse together, decreasing the number of bones, eventually to get to the average number of 206. Regular exercise is important in keeping bones as strong as possible. Activities such as basketball, soccer, gymnastics, running, dancing, and even walking, help to keep bones strong and healthy. Calcium is also important to keep bones strong. Joints, Ligaments, Tendons, and Cartilage Joints are what make it possible for the human body to move. Different joints such as the balland-socket, hinge, gliding, and even saddle joints are spread out throughout the body to help it move. Ball-and-socket joints allow the most range of movement for our joints. This is when the spherical head of one bone fits into the spherical cavity of another. An example of a ball-and-socket joint is like that of the shoulder joint, in which the humerus fits into the socket of the shoulder blade (innerbody.com). Hinge joints are the simplest type of joint and are found in places like the elbows, the joints of fingers and toes, along with the knee. These types of joints only allow movement in one direction. The knee joint is the largest in the body and is somewhat unusual because it can swivel on its axis, allowing the foot to turn from side to side. Gliding joints permit a wide range of sideways movement, as well as some movement

4 Skeletal System 4 in one direction. This type of joint allows the wrist and ankle to twist, along with allowing the head to turn and bend. A more versatile joint than that of a hinge or gliding joint, is called a saddle joint. This joint allows movement in two directions and is what gives the human thumb the ability to cross-over the palm. Ligaments are an essential part of skeletal joints that bind bone-ends together to prevent dislocation and excessive movement that could cause the bones to break. A ligament is a tough band of white, fibrous, slightly elastic tissue. Sometimes ligaments, especially those in the ankle and knee, are often damaged by injury (innerbody.com). Ligaments also have the ability to be torn. A torn ligament is the result from twisting stress when the knee is turned while weight is on the particular leg. Unlike ligaments which attach bone to bone, tendons attach bone to muscle. Tendons are tough, but flexible, and are the structures that transmit the forces which a muscle exerts. Due to the thickness of its fibrous tissue, tendons provide joint stability at the meeting of two bones. The Achilles tendon, which is the strongest tendon in the body, and the Patellar tendon, which is located at the knee joint, are both common tendons in the body. Fingers, toes, and elbows also have various extensor and flexor tendons. Extensor tendons are normally visible through the skin in hands and feet. They have jobs such as unclenching a fist or extending the toes. Flexor tendons, on the other hand, pull on the bones to make a fist, or to curl the toes. In the elbow, the bending, or flexion, is a result of the biceps muscle pulling on its tendon in the upper arm, which is across the elbow joint to the forearm (Wikipedia.org). Tendonitis is a common injury and is defined as an inflammation of the tendon. Cartilage is a flexible, connective tissue found in many parts of the human body. This connective tissue is found in the joints between bones, rib cage, ear, nose, and other parts of the body. Cartilage works as a cushion between joints in the body, so that rubbing of bones against each other doesn t occur (Wikipedia.org). Axial Skeleton The human skeleton is split into two main sections. First is the axial skeleton, and second is the appendicular skeleton. The axial skeleton consists of a total of 80 bones in the head and the trunk, (the sternum and ribs) of the human body. It also provides structural support for the body, protects the brain, spinal cord and other major organs of the chest, along with being attachment points for ligaments and muscles. There a couple main parts of the axial skeleton: skull, rib cage/sternum (breastbone), and vertebral column.

5 Skeletal System 5 The Cranium (or Skull) The skull can be categorized into two groups. First is the Neurocranium, and second is the Splanchnocranium. The frontal, parietal, temporal, occipital, ethmoid, sphenoid, and palatine bones all make up the Neurocranium. The frontal bone is what makes up the forehead part of the skull, while the parietal bones form the roof, or the top of the skull (or cranium). Temporal bones are the bones on either side of the pariental bones, and occipital bones are what form the back and floor of the skull. Forming the front part of the cranial floor is the ethmoid bone; the sphenoid bone contains the sphenoidal sinus cavity. The palatine bones are the bones that are able to be felt at the back of the roof of the mouth. They form the wall of the nasal cavities. The skull is what protects the bodies eyes and brain. Bones of the Face Along with bones of the skull, there are also bones of the face. This is second part of the skull and is called the Splanchnocranium. There are fourteen total bones in the face and they break down as follows: two nasal, two maxilla, two zygomatic, two lacrimal, the mandible, two palatine, and two inferior nasal conchae and vomer. The only bone in the skull that moves is the mandible, or the lower jaw, and is the strongest bone of the face. Maxilla bones are the largest of the face; they are what form together to make the upper jaw (rapidlearningcenter.com). A triangular shaped bone that forms part of the nasal septum is the vomer, and the lacrimal- which are the smallest bone of the face, which is part of the inside wall of the eye orbit. Nasal bones and nasal conchae form the nose and the nasal cavity. Bones of the Ear After the neurocranium and splanchnocranium, (face and cranium) come the bones of the ear. Together, the bones of the ear function to transmit sound waves from the external environment to the fluid filled cochlea (rapidlearningcenter.com). The first bone of the ear is called the malleus, (or hammer), a hammer-shaped bone that is attached to the incus, and attached to the eardrum. The incus (or anvil), is an anvil-shaped bone place in between the malleus and the stapes. This is what connects the incoming sounds waves to the inner ear. The stapes, also known as the stirrup, transmits the sound vibrations from the incus to an oval window. This oval window connect the all the inner ear bones to the cochlea (rapidlearningcenter.com). The Ribs The rib cage, also known as the thoracic cage, is a bony and cartilaginous structure which surrounds the thoracic (chest) cavity and supports the pectoral (shoulder) girdle, forming a core portion of

6 Skeletal System 6 the human skeleton. (wkipedia.org). In total, a normal human rib cage consists of 24 ribs, twelve thoracic vertebrae, and the sternum. The rib cage, along with the skin and associated muscles, makes up the thoracic wall, and provide attachments for muscles of the neck, thorax, upper abdomen, and back. The rib cage protects the lungs and encloses the thoracic cavity. Most ribs are attached in the back to the thoracic vertebrae, while some are attached to the sternum by means of costal cartilage. Due to the ribs elasticity, they allow movement when inhaling and exhaling (Wikipedia.org). The Vertebral Column The vertebral column, also known as backbone or spine, is a column that usually consists of about 24 vertebrae, and protects the spinal cord. Vertebrae are the bones or segments that make up the spinal- or vertebral column. Normally there are 33 vertebrae in humans. Five of the 33 are fused together to form the sacrum (this is the sacral region), which is the base of the spine. Another group of a number of four bones forms the tailbone; these are called coccygeal bones. (wikipedia.org). The remaining 24 vertebrae make up the upper three regions of the vertebral column. These regions are grouped under the names cervical (7 vertebrae), thoracic (12 vertebrae) and lumbar (5 vertebrae), according to the regions they occupy (wikipedia.org). These regions can vary in number depending on additional vertebrae in one area. Small, delicate bones make up the 7 vertebrae of the cervical region. These vertebrae are what allow the neck and head a certain amount of movement. They also allow the skull to move up and down, and the upper neck to twist left and right. Conversely, the twelve thoracic bones support only some rotation. The lumbar region of the vertebral column has the responsibility to support more weight than other vertebrae, due to the fact that they allow significant side-bending and a small amount of rotation. Appendicular Skeleton The word appendicular describes the noun appendage, which means a part that is joined to something larger. These parts are involved in locomotion (lower limbs) of the axial skeleton and handling of objects in the environments (upper limbs) (Sherk). Unlike the bones of the axial skeleton, which are fused, the bones of the appendicular skeleton are not fused. Bones which are not fused allow a much greater range of motion. In total, there are 126 bones in this part of the skeleton. Sixty-four of these are part of the shoulders and upper limbs, and 62 are part of the pelvis and lower limbs. There are four main regions of the appendicular skeleton. These regions are: the pectoral girdle, upper limbs, pelvic girdle, and the lower limbs.

7 Skeletal System 7 There are four total bones in the pectoral girdle; they are the clavicle and scapula, on both the left and right side. The clavicle connects the upper limb to the trunk. The scapula is a bone that lies on the back of the trunk. The upper limbs consist of the arm, forearm, hand, and wrist. The humerus (or arm), ulna, and radius (forearm), are six of the 64 bones of the upper limbs; one of each, on each side of the body. Fiftyeight of the bones make up the hand. These bones are: the left and right carpals (16 bones, also known as wrist); the metacarpals (10 bones), proximal phalanges (10), middle phalanges (8), distal phalanges (10), and sesamoid (4 bones) are all part of the hand. The hand and arm allow objects to be moved, picked up, and manipulated by the human body. Two bones make up the pelvic girdle. These bones are the hip bones, or os coxa (innominate bone). The hip bone is made up by the fusion of three different bones; the ilium, ischium, and the pubis. The pelvic girdle protects vital lower organs such as the bladder, and reproductive organs. Lastly, the lower limbs are also part of the appendicular skeleton. The thigh and leg, which consist of eight bones total, are part of the lower limbs. The femur, tibia, patella, and fibula are the bones that make up the thigh and leg. There is one of each of these bones, on each side of the body, adding up to the total of eight bones. The feet consist of 56 bones and break down a lot like the hands. There are 14 tarsal bones (the ankle), ten metatarsal bones, ten proximal phalanges, ten distal phalanges, and eight middle phalanges, along with four sesamoid bones. The lower limbs are what help the human body to walk and move around. Diseases/Conditions, Occupations Osteoporosis is the most common type of bone disease (Eckman). It is the thinning of bone tissue and loss of bone density over time and occurs when the body fails to form enough new bone. To ensure proper bone formation, calcium and phosphate are essential. When a person has osteoporosis, they might feel pain in the bone, or tenderness of the bone. They may also experience loss of height over time, back pain, and neck pain. There are different tests and treatments that can be done if one has osteoporosis. Bone mineral density testing, a special type of spine CT scan, or even a spin or hip x-ray, can all help to show bone fractures or collapses. Treatment and medication used to prevent and treat osteoporosis include things like: bisphosphates, calcitonin, raloxifene, and exercise. Diet is also an important part of preventing, or treating osteoporosis. Foods with calcium, vitamin D3, and phosphate are all beneficial to bones.

8 Skeletal System 8 Rheumatoid Arthritis is another condition dealing with bones of the body. It is defined as inflammation of one or more joints, which will result in pain, swelling, stiffness, and limited movement. Cartilage normally protects the joint, allowing easy movement, but when it breaks down is when one might experience arthritis. This is because without any cartilage, the bones rub against each other, causing pain and swelling. X-rays can often show where a person has arthritis and what is causing it. Treatment for arthritis can vary depending on severity, which joints are affected, and age. Medications and various treatments can be used to eliminate arthritis, along with exercise. Exercise is necessary to maintain healthy joints, relieve stiffness, reduce pain and fatigue, and improve muscle and bone strength (Borigini). Surgery is also an approach in rebuilding a joint with arthritis. This is call arthroplasty, but knee joint replacement sometimes is the better choice because it helps maintain a more normal lifestyle. Bursitis is inflammation of the fluid-filled sac (bursa) that lies between a tendon and skin, or between a tendon and bone. Bursae are fluid-filled cavities near joints that assist movement and reduce friction between moving parts (Vorvick). This condition can be caused by arthritis, gout, infection, and even over-use. It most commonly appears in joints such as the shoulder, knee, elbow, and hip. Ibuprofen, an anti-inflammatory drug may relieve any pain and swelling that comes with Bursitis. Sometimes, when Bursitis is caused by infection, the infected bursa must be drained surgically. Spina Bifida and Scoliosis are both conditions that have to do with the spine. Spina Bifida is a birth defect in which the backbone and spinal canal do not close before birth (Zieve). Scoliosis is the curving of the spine which may be present at birth, or may be developed. If the curve of the spine is severe, surgery that involves correcting the curve and fusing the bones together may be required. Part of this surgery is holding the bones in place with one or two metal rods that are held down with hooks and screws until the bone heals together (Zieve). Spina Bifida can also fixed by surgically closing the opening of the spine after birth. Before a woman becomes pregnant, it could be beneficial to take daily folic acid supplements; this could decrease the incidence of spina bifida by up to 75%. Unfortunately, there is no known cure for the nerve damage that is caused by spina bifida. Pediatric Neurosurgeons do have the ability though to prevent infection by operating to close the opening of the back. Apart from a Pediatric Neurosurgeon, Chiropractors, Orthopedic Surgeon, and Rheumatologists are all types of occupations that deal specifically with parts of the skeleton (or musculoskeletal system). A Chiropractor usually treats injuries of the back, neck or spine, joint pain and headaches. Orthopedic Surgeons are generally focused on anything that has to do with treatment of bone or skeleton-related problems. The neck, back, arms, elbows, hands, hips, knees, and spine are all involved in things in which

9 Skeletal System 9 they specialize. A Rheumatologist is a pediatrician that specializes in treatment of arthritis and other diseases of the joints, bones and muscles. History In 1741, Nicholas Andry, a professor of medicine at the University of Paris, published a work that described different methods of preventing and correcting deformities in children. On November 8, 1895, Wihelm Conrad Rontgen discovered the x-ray.jean-andre Venel is credited as the father of orthopedics, which is the study of the musculoskeletal system in the 18 th century. He established the first hospital for the treatment of children s skeletal deformities in 1780 (Anderson). In the 1890s, D.D. Palmer, a magnetic healer, founded chiropractic practice and later his son, B.J. Palmer helped to expand it. Gender-bases Differences Comment [j1]: d Although the main structure of the skeleton is the same in both male and female bodies, there are some specific differences. The main difference is the pelvis. In females, the pelvis is flatter, and somewhat larger. This enables the head of a fetus to pass when a female is having a child. Another difference is the coccyx of female s pelvis is oriented more inferiorly whereas the man s coccyx is usually oriented more anteriorly (Wikipedia.org). This difference is better for a developing fetus. Other differences of male and female skeletons are things like men have thicker and slightly larger limbs, and bigger teeth. Females tend to have more rounded shoulder blades, along with narrower rib cages.

10 Skeletal System 10 References Anthony, Catherin Parker; DeLisa, Joel; Stolov, Walter C.; Thibodeau, Gary A. The Skeleton: Skeletal System. (2000, Oct.) PATTS. Callaway, Everett. List of Tendons in the Body. (2011, Mar. 9). Wikimedia Foundation, Inc. Eckman, Ari S. Osteoporosis (2010, Aug. 8) A.D.AM., Inc. Sherk, Stephanie Dionne. Skeletal Development. (2011) Unknown Author. Skeletal System 2: Axial Skeleton. (2011) Rapid Learning, Inc. Skeleton.html Unknown Author. Human Rib Cage. (2011, Mar. 9) Wikimedia Foundation, Inc. Unknown Author. Spina Bifida (2011, May 13) Wikimedia Foundation, Inc. Unknown Author. Chiropractic (2011, May 20) Wikimedia Foundation, Inc. Unknown Author. Human Skeleton. (2011, May 19) Wikimedia Foundation, Inc.

11 Skeletal System 11 Unknown Author. Ligaments (An Overview). (2001) HowToMedia, inc. Zieve, David. Scoliosis (2009, Sep. 17) A.D.A.M., Inc. Comment [j2]: Be careful with Wikipedia sites anyone can add or delete information not used as a formal reference paper.

12 Skeletal System 12 References.