Skeletal System Flashcards
Functions of the Skeletal System
Support
Storage of Minerals (Calcium)
Storage of lipids (Yellow Marrow)
Blood Cell Production (Red Marrow)
Protection
Leverage (Force of motion)
Axial Skeleton
The Skull
The Vertebral Column
The Thoracic Cage
Appendicular Skeleton
The bones of the limbs
* Arm and Leg Bones
The Girdles
* Pectoral and Pelvic
Bone Classification
Shape
Internal Tissues
Bone Markings
Bone Shapes
- Long Bones
- Flat Bones
- Irregular Bones
- Short Bones
- Based on Formation
- Sesamoid bones
- Wormian
Long Bones
Are long and thin
Are found in arms, legs, hands, feet, fingers, and toes
Short Bones
Are small and thick
Ex. Ankle, Carpals
Flat Bones
Are thin with parallel surfaces
Are found in the skull, sternum, ribs, and scapula
Irregular Bones
Have Complex shapes
Ex. Spinal vertebrae, pelvic bones
Sesamoid Bones
Are small and flat
Develop inside tendons or ligaments near joints of knees, hands, and feet
Wormian Bones
Are small, irregular bones. Function to fuse two other bones together.
Are found between the flat bones of the skull
Long Bones
The Femur
Diaphysis - The Shaft
Epiphysis - Wide part at each end. Articulates with other bones
Metaphysis - Where diaphysis and epiphysis meet
Diaphysis
A heavy wall of compact bone, or dense bone
A central space called marrow cavity
The Epiphysis
Mostly Cancellous (Spongy) Bone
Covered with compact bone (Cortex)
Flat Bones
What the bone looks like inside
Resembles a sandwhich of spongy bone
Between 2 layers of compact bone
Characteristics of Bone Tissue
Dense matrix, Containing deposits of calcium salts
Bone cells (Osteocytes) within lacunae organized around blood vessels
Bone Tissue
Dense, supportive connective tissue
Contains specialized cells
Produces solid matrix of calcium salt deposits
Around collagen fibers
Canaliculi
Little grooves in the matrix
Form pathways for cell processes
Exchange nutrients and wastes
Periosteum
Covers outer surfaces of bones
Consists of outer fibrous and inner cellular layers
Osteon Haversion System
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The basic unit of mature compact bone
Osteocytes are arranged in concentric lamellae
Around a central canal containgin blood vessels
Perpendicular to the central canal
Prependicular to the central canal
Carry blood vessels into bone and marrow
Allow connection of osteons
Cancellous (Spongy) Bone
Does not have osteons
The matrix forms an open network of trabeculae
Trabeculae have no blood vessels
Red Marrow
The space between trabeculae is filled with red bone marrow:
Which has blood cessels
Forms red blood cells (Hematopoiesis)
and supplies nutrients to osteocytes
Yellow Marrow
In some bones, spongy bone holds yellow bone marrow:
is yellow because it stores fat
Bone Development
Human bones grow until about age 25
Osteogenisis - Bone Formation
Ossification - The process of replacing other tissues with bone
2 forms of bone growth
Endochondral Growth
Appositional Growth
Endochondral Growth
Bone grows in length
Appositional Growth
Bone grows in width
Epiphyseal Lines
When long bone stops growing, after puberty:
Epiphyseald cartilage disappears (epiphyseal plate)
In visible on X-Rays as an epiphyseal line
Bone Remodeling Process
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Effects of exercise on Bone
Meneral recycling allows bones to adapt to stress
Heavily stressed bones becom thicker and stronger
Bone Degeneration
Bone degenerates quickly
Up to 1/3 of bone mass can be lost in a few weeks of inactivity
Fractures
Cracks or breaks in bones
Caused by physical stress
Types of Fractures
Pott’s Fracture - Ankle and affects both bones of the leg
Comminuted Fractures -Shatter into fragments
Transverse Fractures - Break across its long axis
Spiral Fractures - Twisting Stress spread along length of the bone
Displaced Fractures - produce new and abnormal bone arrangements
Colles’ fracture - Break in the distal portion of the radius (Reaching out to catch a fall)
Greenstick Fracture - Only one side is broked and the other is bent
Epiphyseal Fractures - Breaks at the epiphyseal lines
Compression Fractures - Occur in vertebrae subjected to extreme stresses
Age and Bones
Bones become thinner and weaker with age
Osteopenia begins between ages 30 and 40
Women lose 8% of bone mass per decade, men 3%
Effects of Bone Loss
The epiphyses, vertebrae, and jaws are most affected:
Resulting in fragile limbs
Reduction in height
Tooth Loss
Osteoporosis
Sever bone loss
Affects normal function
Over age 45, occurs in:
29% of women
18% of men
Hormones and Bone Loss
Estrogens and androgens help maintain bone mass
Bone loss in women accelerates after menopause
Cancer and Bone Loss
Cancerous tissues release osteoclast-activation factor:
That stimulates osteoclasts
And produces severe osteoporosis
Classification of Joints
Synarthrosis - immoveable = sutures
Amphiarthrosis - somewhat moveable = distal tibia-fibula, vertebral discs
Diarthrosis (Synovial) - freely moveable = 6 Subtypes
6 Synovial Joints
Gliding
Hinge
Pivot
Ellipsoidal
Saddle
Ball-and-socket
Gliding Joints
Flattened or slightly Curved faces
Limited motion (nonaxial)
Hinge Joints
Angular Motion in a single plane (Monaxial)
Pivot Joints
Rotation only (Monaxial)
Ellipsoidal Joints
Oval articular face within a depression
Motion in 2 Planes (Biaxial)
Saddle Joints
2 concave faces, straddled (biaxial)
Ball-and-Socket Joints
Round articular face in a depression (Triaxial)
Bone Remodelling Process
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