Flashcards in Skeletal System Deck (67)
5 Skeletal Functions
1) Supports the body
2) Protects soft body parts
3) Produces blood cells (in red bone marrow)
4) Stores minerals (calcium and phosphate) and fat (yellow bone marrow)
5) Permits flexible body movement (via attached muscles)
5 Types of Bones
Longer than they are wide - e.g., femur
Generally cube-shaped, e.g. carpals
Thin bones consisting of spongy bone sandwiched between two parallel layers of compact bone (e.g. skull bones)
Embedded in tendons and increase muscle leverage (e.g., patella)
Bones that don't fit into any other category
A long bone is comprised of...
Compact bone and spongy bone
End of a bone
Shaft of a bone
Space in compact bone, especially in the diaphysis (shaft)
Living tissue composed of tubular units called osteons
Bone cells, housed in the lacunae.
Spaces in which osteocyte reside
Layer of matrix made with calcium phosphate and collagen fiberfs
Lighter than compact bones, but still strong. Composed of numerous thin plates called trabeculae, separated by uneven spaces, which often contain red bone marrow.
Not as strong as bone, but more flexible, composed of many collagenous and elastic fibers. Lack of nerves allows for suitable "padding", but a lack of blood vessels results in slow healing.
Cartilage forming cells that lie within lacunae
Firm but somewhat flexible; found in ends of long bones, nose, larynx, trachea
Stronger than hyaline; found in disks between vertebrae
More flexible than hyaline cartilage. Found in ear flaps.
Formation of bone
Bone development between sheets of fibrous connective tissue (used in flat bones)
Cartilage provides a "template" that is replaced by bone (used by most bones)
Undifferentiated connective tissue
Growth plate via which bones grow and lengthen
Males stop growing around age...
Females stop growing around age...
A chemical messenger (protein or steroid) that is produced in one part of the body and acts on another.
Stimulates general bone growth and growth of the epiphyseal plates.
Increases growth during adolescence by stimulating osteoblast activity (estrogen is essential for bone maintenance in adult females and males).
Converted to a hormone to allow calcium absorption in intestines.
Role of bone in homeostasis
Calcium, important in cell signaling, nerve and muscle function, and blood clotting, stored in bones. Body regulates calcium levels in the blood via hormones - parathyroid hormone and calcitonin.
Increases blood calcium by accelerating bone recycling, stimulates osteoclast.
Decreases blood calcium by stimulating osteoblast.
Weakening of bones due to decreased bone mass.
Bone absorption exceeds formation by when?
Age 40, usually.
Risk factors for osteoperosis
Woman, white or Asian, thin, family history, smoking, diet low in calcium, excessive caffeine or alcohol consumption, sedentary lifestyle.
Four stages of bone repair
2) Fibrocatilaginous callus
3) Bony callus
Blood clot; forms between 6-8 hours after a bone break
Forms between broken bones, about 3 weeks after a break
The fibrocartilaginous callus is converted into bone, about 3-4 months after a break.
Bony callus is replaced by new compact bone tissue. Osteoclasts absorb spongy bone to create the medullary cavity.
Where bone meets bone (aka "joint")
Types of Articulations
Usually immovable, such as the sutures between cranial bones
Tend to be slightly movable such as the intervertebral disks
Freely movable joints - several classes - including the knee joint, ball and socket joint (shoulder, hip), and hinge joints (elbow).
Joint angle decreases
Joint angle increases
Body part moves toward midline
Body part moves away from midline
Body part moves around its own axis
Body part moves in a cone shape
Sole of foot turns inward
Sole of foot turns outward
Lies in the mid-line of the body
Lies away from the mid-line axis
Anchors the tongue; attachment point for muscles used in swallowing