Protection, Support, and Movement

1
Protection, Support, and Movement

• Chapter 6

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Integumentary System

• An animals outer covering
• Examples
• Chitin-hardened cuticle of many invertebrates
• Vertebrate skin and its derivatives

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Endoskeleton

• All vertebrates
• Fins or limbs attach to skeleton at pectoral and
  pelvic girdles

Generalized mammal
Figure 37.10cPage 650
pelvic girdle
pectoral girdle
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Functions of Bone

• Interact with muscle to enable movement
• Support and anchor muscles
• Enclose and protect internal organs
• Store calcium and phosphorus
• Produce blood cells

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Human Skeleton
Stepped Art
Figure 37.11Page 651
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Long Bone Structure

• Compact bone
• Spongy bone
• Central cavity contains yellow marrow

nutrient canal
contains yellow marrow
compact bone tissue
spongy bone tissue
Fig. 37.12 (1)Page 652
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Compact Bone Structure

• Mature compact bone consists of many cylindrical
  Haversian systems

Haversian system
blood vessel
outer layer of dense connective tissue
spongy bone tissue
Fig. 37.12 (2)Page 652
compact bone tissue
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Bone Marrow

• Yellow marrow
• Fills the cavities of adult long bones
• Is largely fat
• Red marrow
• Occurs in spongy bone of some bones
• Produces blood cells

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Bone Remodeling

• In adults, bone building and bone breakdown
  continue constantly
• Osteoblasts deposit bone
• Osteoclasts secrete enzymes that degrade it
• Remodeling adjusts bone strength and helps
  maintain blood calcium levels

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Bone Density

• Exercise can increase bone density
• Osteoporosis is a decrease in bone density
• May occur when the action of osteoclasts outpaces
  that of osteoblasts
• May also occur as a result of inability to absorb
  calcium

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Joints

• Areas of contact or near contact between bones
• Fibrous joints
• Short connecting fibers join bones
• Synovial joints
• Move freely ligaments connect bones
• Cartilaginous joints
• Straps of cartilage allow slight movement

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Tendons Attach Muscle to Bone
muscle
tendon
bursae
synovial cavity
Figure 37.15Page 654
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Skeletal Muscle

• Bundles of striped muscle cells
• Attaches to bone
• Often works in opposition

biceps
triceps
Figure 37.17Page 654
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Major Human Muscles
triceps brachii
biceps brachii
deltoid
pectoralis major
trapezius
serratus anterior
external oblique
latissimus dorsi
rectus abdominus
gluteus maximus
adductor longus
biceps femoris
sartorius
quadriceps femoris
gastrocnemius
tibialis anterior
Figure 37.18Page 655
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Muscle Tension

• Mechanical force a contracting muscle exerts on
  an object
• For a muscle to shorten, muscle tension must
  exceed the load that opposes it
• The load may be the weight of an object or
  gravitys pull on the muscle

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Two Types of Contraction
contracted muscle cant shorten
contracted muscle can shorten
isotonic contraction
isometric contraction
Figure 37.24Page 660