The Skeletal System
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The Skelet al System
description
The Skeletal System. FYE: Your Bones…. Bones aren ’ t just pieces of your skeleton. They are a connective tissue impregnated with minerals!. Bones aren ’ t dead!. They have cells, bloody supply & nerves (feelings!). Bones are strong!. - PowerPoint PPT Presentation
Transcript of The Skeletal System
The Skeletal System
FYE: Your Bones… Bones aren’t just pieces of your skeleton
They are a connective tissue impregnated with minerals! Bones aren’t dead!
They have cells, bloody supply & nerves (feelings!)
Bones are strong!
Standing still the force on hip = 3x bodyweight (muscle pull) & a running man exerts a dead wt force of ~590 lbs!
The Skeletal System
Parts of the skeletal system
Some Vocab…• BONE = Osseous Tissue• Osteology = Study of bones• Arthrology = Study of joints• Kinesiology = Study of movement
Bones
Cartilage
Ligaments (connect bone to bone)
Tendons (connect muscle to bone)
Functions of the Skeletal System
Protects internal organs
Storage Calcium & Phosphate Fat cells (in yellow marrow!)
Produces blood= Hematopoiesis Red marrow makes cells Found in: pelvis, ribs, clavicle,
vertebra, skull, ends of long bones
3 million new each second!
Support For wt of entire body Framework for muscle attachment
Bone Classification: Shapes
Figure 6-1
Femur, Phalanges & metacarpals Tarsals
Sternum, scapula, ribs
Clavicle, patella
An Overview of the Skeleto
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An Overview of the Skeleton
Axial Division Forms center axis for everything to attach to Includes: 80 bones
Ribs, Sternum, Vertebra (including sacrum) & Skull (including the hyoid)
Appendicular Division Includes: 126 bones
Upper & lower extremities, Pelvis & Shoulder (clavicles & scapula)
An Overview of the Skeleton
Skeletons differ in shape based on what?
Why is looking at bones important/useful?
An Overview of the Skeleton How are male & female skeletons different?
A. Skull: Frontal bone Cranium Mandible
B. Pelvis: Pelvic outlet Pubic angle
An Overview of the Skeleton The Vertebral Column
A. Cervical: (7) C1 = Atlas – holds head up attaches to skull (nod) C2 = Axis – pivots (no) C7 = Vertebral prominens – prominent landmark
B. Thoracic: (12) Each joins with a rib
C. Lumbar: (5) Holds wt of body, takes most stress = biggest!
D. Sacrum: (1) (5 fused together)
Supports & strengthens pelvis/hips
E. Coccyx: (1) (4 fused together)
Bone Anatomy
Bone Tissue
Two types: Compact & Spongy
Compact Bone Layers of compact cover all
bone surfaces, except at joints
Found where stresses occur
Bone TissueSpongy Bone
Network of bony rods (trabeculae) Found in center & in epiphysis Lighter to decrease
wt of skeleton Spaces filled with
marrow
BONE CELLS
1. Osteocytes Mature bone cells in compact bone
2. Osteoblasts Cells that make new bone (osteogenesis)
3. Osteoclasts Bone eaters - secrete acid that dissolves
matrix (osteolysis) to release stored minerals
= Found in Endosteum & Periosteum
Bone Formation and Growth
Begins ~6wks after fertilization - embryo is ~12mm long
• Continues until 18-25 yrs
• Epiphyseal Plates(discs) in ends of long bone become solid lines when done growing!
Bone Growth
Figure 6-6
Bone Remodeling/Homeostasis
Remodeling - Continuous breakdown and reforming of bone tissue - 18% turned over/year
enables skeleton to adapt to new stresses
inactivity = degeneration FYE: Cast on leg for 6 wks - leg loses 1/3 bone mass!
FYE: your oldest bones are ~7 yrs!
needed for Ca regulation - bones store 2-4 lbs Osteoclasts break down worn-out bone cells & put
Ca in blood as needed
Osteoblasts pull Ca out of blood & build new
FYE: Continues until late 40’s then bone start to get old too!
Disorders in Bone Growth & Remodeling
Osteoporosis = bone mass reduced, can happen at any age
inactivity low Ca age (males - lose 3%/decade starting in 30’s,
females lose 8%)
Disorders in Bone Growth & Remodeling
Osteomalacia (Rickets) = Soft Bones from lack of Vit.D causes low Ca
Disorders in Bone Growth & Remodeling
Osteogenesis Imperfecta = Genetic disorder affecting collagen fiber formation (1 in 20,000)
Disorders in Bone Growth & Remodeling
Achondroplasia (Dwarfism) = Genetic disorder affecting cartilage formation mainly at epiphyses
Disorders in Bone Growth & Remodeling
Acromegaly (Giantism) = Excess growth hormone - most often after epiphyseal plates closed
Disorders in Bone Growth & Remodeling
Marfan’s Syndrome = Defective CT - excess cartilage at epiphyseal plates
The Axial Division: The Skull
Figure 6-10
The Axial Division: The Skull
Figure 6-11(a)
The Axial Division: The Skull
Figure 6-11(b)
