the skeletal system the general framework of the body is built up mainly of a series of bones,...
TRANSCRIPT
The SkeletalSystem
THE GENERAL framework of the body is built up mainly of a series of bones, supplemented, however, in certain regions by pieces of cartilage; the bony part of the framework constitutes the skeleton.
The skeleton supports the body, protects vital organs, and works in conjunction with the muscles to cause movement.
Functions of the Skeletal System
________________________________ strong structural frame; every other part of the body is
“hung” on bones like a hanger
________________________________ internal organs (brain by cranium, heart & lungs by ribs &
sternum, spinal cord by spinal column)
________________________________ attachment for muscles that move us; lever systems; bones
are hinged with muscles crossing the joints
Functions of the Skeletal System
________________________________ red marrow produces blood cells within internal
structures of long bones
________________________________ calcium & phosphate storage; needed for muscle
contraction, nerve cell function, & movement of materials across cell membranes
________________________________ relatively unique shape to organisms;
height/weight/width; structure sub-serves function
The Sexes A baby's skeleton has 350 bones, but many of these fuse to
give an adult a total of 206 bones.
________________________________has broader shoulders than a woman's, a longer ribcage, and a narrow pelvic girdle optimized for walking/running/jumping.
________________________________has the same bone complement as a man's but is slightly smaller (lighter) and less robust, with a wider pelvic opening to assist childbirth.
There is a list of the major criteria shown in the chart on the following page to further distinguish between the sexes.
Male Female
Skull is heavy and rough Lighter and smoother
Forehead is usually sloping More vertical
Sinuses are large Smaller
Cranium is large Smaller (by about 10%)
Mandible is large and robust Lighter and smaller
Teeth are large Smaller
PELVIS
Narrow, robust, heavy, rough Broad, light, smooth
Pelvic inlet is heart shaped Oval to round shape
Iliac fossa is deep Relatively shallow
Ilium extends further above the sacrum More vertical, less above the sacroiliac
Angle under the symphysis is usually much less than 90 degrees
Angle is often greater than 100 degrees
Sacrum is long, with a pronounced sacral curvature
Broad, short less curvature
Coccyx points anteriorly Points inferiorly
Bone weight is heavy Lighter
Bone markings are prominent Less prominent
Axial & Appendicular Skeleton
________________________________ the joints make it possible for a considerable degree of
freedom for the upper and lower limbs. includes the pectoral and pelvic girdles and the bones of
the arms, forearms, wrists, hands, thighs, legs, and feet. Fractures and dislocations are more common in this part
of the skeleton.
__________________ principle supportive structure of the body and is oriented
along its medial longitudinal axis. includes the skull, vertebrae, sternum, ribs, and hyoid
bone.
The skeletal system accounts for about 14% of our body weight. In the adult skeleton the 206206 distinct bones, are allocated as follows:
Axial Skeleton
Vertebral column
Skull
Hyoid Bone
Ribs & Sternum
Appendicular Skeleton Upper Extremities
Lower Extremities
Auditory OssiclesTOTAL
BONES
Skeletal actually means “________________________”, bones appear lifeless but are living systems that grow, mature, repair & recycle (remodel)
Bones are composed of living tissue (bone cells, fat cells, blood vessels) and non-living tissue (H2O and minerals)
Bones are classified into 5 main types based on shape
• Long bones
• Short bones
• Flat bones
• Irregular bones
• Sesamoid bones
________________________________
Greater in length than width Designed to absorb stress from body & leverage
(used in locomotion & weight bearing) – STRUCTURE SUBSERVES FUNCTION!
Diaphysis (shaft) and epiphyses (ends of bone) Bone marrow activity (production of blood cells)
________________________________
Equal in length & width Form a shape roughly equal to a cube No bone marrow activity Examples –
________________________________
Thin & flat Offer protection & considerable
surface area for muscle attachment No bone marrow activity Examples –
________________________________
Complex shapes Not easily grouped into other 3
categories No bone marrow activity Examples –