Download Cellular Biology

Structure and Function of
the Musculoskeletal
System
Chapter 41
1
Skeletal System





Forms the body
Supports tissues
Permits movement by providing points of
attachment for muscles
Site of blood cell formation
Mineral storage
2
Mosby items and derived items © 2006 by Mosby, Inc.
Bone


Rigid connective tissue
Constituents



Cells
Fibers
Ground substance
3
Mosby items and derived items © 2006 by Mosby, Inc.
Bone Tissue

Osteoblasts





Derived from mesenchymal cells
Produce type I collagen
Respond to parathyroid hormone
Produce osteocalcin
Synthesize osteoid

Nonmineralized bone matrix
4
Mosby items and derived items © 2006 by Mosby, Inc.
Bone Tissue

Osteocytes


A transformed osteoblast that is surrounded in
osteoid as it hardens from deposited minerals
Osteoclast



The major reabsorptive cell of the bone
Large, multinucleated cells
Contain lysosomes filled with hydrolytic enzymes
5
Mosby items and derived items © 2006 by Mosby, Inc.
Bone Matrix





35% organic and 65% inorganic
Collagen fibers
Calcium and phosphate minerals
Proteoglycans
Glycoproteins
6
Mosby items and derived items © 2006 by Mosby, Inc.
Bone Tissue

Compact (cortical) bone


85% of the skeleton
Haversian system


Spongy (cancellous) bone



Haversian canal, lamellae, lucunae, osteocyte, and
canaliculi
Lack haversian systems
Trabeculae
Periosteum
7
Mosby items and derived items © 2006 by Mosby, Inc.
Compact Bone
8
Mosby items and derived items © 2006 by Mosby, Inc.
Bone


206 bones
Axial skeleton

80 bones


Skull, vertebral column, thorax
Appendicular skeleton

126 bones

Upper and lower extremities, the shoulder girdle, the
pelvic girdle
9
Mosby items and derived items © 2006 by Mosby, Inc.
Skeleton
10
Mosby items and derived items © 2006 by Mosby, Inc.
Bones

Long bones



Diaphysis
Metaphysis
Epiphysis




Epiphyseal plate
Epiphyseal line
Medullary cavity
Endosteum
11
Mosby items and derived items © 2006 by Mosby, Inc.
Long Bone
12
Mosby items and derived items © 2006 by Mosby, Inc.
Bones



Flat bones
Short bones (cuboidal bones)
Irregular bones
13
Mosby items and derived items © 2006 by Mosby, Inc.
Bone Remodeling



Bone-remodeling units
Repairs microscopic injuries and maintains
bone integrity
Phases



Activation of the remodeling cycle
Reabsorption
Formation of new bone
14
Mosby items and derived items © 2006 by Mosby, Inc.
Bone Remodeling
15
Mosby items and derived items © 2006 by Mosby, Inc.
Bone Wound Healing





Hematoma formation
Procallus formation
Callus formation
Callus replacement
Remodeling
16
Mosby items and derived items © 2006 by Mosby, Inc.
Joints


Site where two or more bones meet
Promote stability and mobility to the skeleton
17
Mosby items and derived items © 2006 by Mosby, Inc.
Joints

Joint classifications based on movement



Synarthrosis
Amphiarthrosis
Diarthrosis
18
Mosby items and derived items © 2006 by Mosby, Inc.
Joints

Joint classifications based on structure

Fibrous


Cartilaginous


Suture, syndesmosis, gomphosis
Symphysis and synchondrosis
Synovial

Joint capsule, synovial membrane, joint cavity,
synovial fluid, articular cartilage
19
Mosby items and derived items © 2006 by Mosby, Inc.
Joints
20
Mosby items and derived items © 2006 by Mosby, Inc.
Joints
21
Mosby items and derived items © 2006 by Mosby, Inc.
Joints
22
Mosby items and derived items © 2006 by Mosby, Inc.
Joints
23
Mosby items and derived items © 2006 by Mosby, Inc.
Joints
24
Mosby items and derived items © 2006 by Mosby, Inc.
Skeletal Muscles






Millions of individual muscle fibers that
contract and relax to facilitate movement
75% water, 20% protein, 5% organic and
inorganic compounds
350 named muscles (most are paired)
2 to 60 cm long
Fusiform muscles
Pennate muscles
25
Mosby items and derived items © 2006 by Mosby, Inc.
Skeletal Muscles
26
Mosby items and derived items © 2006 by Mosby, Inc.
Skeletal Muscles
27
Mosby items and derived items © 2006 by Mosby, Inc.
Skeletal Muscles

Whole muscle






Fascia
Epimysium
Tendon
Perimysium
Fascicles
Endomysium
28
Mosby items and derived items © 2006 by Mosby, Inc.
Skeletal Muscle
29
Mosby items and derived items © 2006 by Mosby, Inc.
Muscle

Skeletal muscle


Voluntary
Striated


Motor unit



Sarcomeres
Lower motor neurons
Innervation ratios
Sensory receptors
30
Mosby items and derived items © 2006 by Mosby, Inc.
Motor Units
31
Mosby items and derived items © 2006 by Mosby, Inc.
Muscle Fibers





Myofibrils
Myoblasts
White muscle (type II fibers)
Red muscle (type I fibers)
Muscle membrane


Sarcolemma and basement membrane
Sarcoplasm
32
Mosby items and derived items © 2006 by Mosby, Inc.
Muscle Fibers

Sarcotubular system



Transverse tubules
Sarcoplasmic reticulum
Sarcomere



Actin
Myosin
Troponin-tropomyosin complex
33
Mosby items and derived items © 2006 by Mosby, Inc.
Myofibrils
34
Mosby items and derived items © 2006 by Mosby, Inc.
Myofibrils
35
Mosby items and derived items © 2006 by Mosby, Inc.
Muscle Fibers


Creatine and creatine kinase
Phosphate, chloride, calcium, magnesium,
sodium, potassium
36
Mosby items and derived items © 2006 by Mosby, Inc.
Muscle Contraction

Activation



Coupling
Contraction


Muscle fiber action potential
Cross-bridge theory
Relaxation
37
Mosby items and derived items © 2006 by Mosby, Inc.
Muscle Contractions and
Movement

Types of muscle contractions


Isometric contraction
Isotonic contraction



Eccentric
Concentric
Muscle movement


Agonist
Antagonist
38
Mosby items and derived items © 2006 by Mosby, Inc.
Test of Bone Function





Gait analysis
Serum calcium and phosphorus
X-rays
Angiography
Bone scanning
39
Mosby items and derived items © 2006 by Mosby, Inc.
Test of Joint Function




Arthrography
Arthroscopy
MRI
Synovial fluid analysis
40
Mosby items and derived items © 2006 by Mosby, Inc.
Test of Muscular Function



Serum creatine kinase
Myoglobin
EMG
41
Mosby items and derived items © 2006 by Mosby, Inc.
Aging and the Musculoskeletal
System

Bones




Bone loss
Stiff, brittle, decreased strength
Bone remodel time is lengthened
Joints


Cartilage becomes more rigid, fragile, stiff
Decreased range of motion
42
Mosby items and derived items © 2006 by Mosby, Inc.
Aging and the Musculoskeletal
System

Muscles



Sarcopenia
Decrease in muscle strength and bulk
Reduced oxygen intake, basal metabolic rate, and
lean body mass
43
Mosby items and derived items © 2006 by Mosby, Inc.