Locomotion and Support Systems Outline Chapter 20 page

Locomotion and Support Systems Outline Chapter 20 page 402 -415 Diversity of Skeletons Hydrostatic Skeleton Exoskeletons Endoskeletons Human Skeletal System Axial Skeleton Appendicular Skeleton Human Muscular System The Muscles Muscle Contraction 1

Locomotion and Support Systems Hydrostatic Skeleton Functions Supports body form Provides resistance for the contraction of muscles to act against Source Some organisms use their fluid-filled gastrovascular cavity Others use their fluid-filled coelom 2

Locomotion in an Earthworm 3

Locomotion and Support Systems Exoskeletons and Endoskeletons Exoskeleton - External Skeleton Molluscs - composed of calcium carbonate Arthropods - composed of chitin Endoskeleton - Internal Skeleton Echinoderms and vertebrates Mineralized bone and cartilage Grows as the animal grows Does not limit space for internal organs Supports greater weight 4

Exoskeleton 5

The Vertebrate Endoskeleton 6

Locomotion and Support Systems Human Skeletal System Functions Supports and protects the body Permits movement Provides resistive foundation for muscles to act against Bones store calcium and phosphate ions Certain bones produce red blood cells 7

Locomotion and Support Systems 8 Bone Growth and Renewal Cartilage structures in early development act as models for future bones Calcium salts deposited in matrix by cartilage cells and later by osteoblasts Endochondral ossification Osteoclasts Break down bone Remove worn cells Deposit calcium in the blood Work with osteoblasts to heal broken bones

Locomotion and Support Systems Anatomy of a Long Bone Gross Main shank Thick outer cylinder of compact bone Medullary cavity in center Spongy bone at ends Details Compact bone Unit of structure called osteon Concentric lamellae arranged around central canal Osteocytes lie in lacunae at lamellar boundaries Spongy bone Numerous bars and plates separated by irregular spaces Spaces filled with red bone marrow 9

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The Human Skeleton 12

Locomotion and Support Systems The Axial Skeleton Lies in the midline of the body Consists of The skull The vertebral column The sternum, and The ribs 13

Locomotion and Support Systems The Skull Formed by cranium and facial bones Major bones are named after The lobes of the brain, and The facial bones Foramen magnum Opening at base of skull Where spinal cord connects to brain Bones of cranium surround sinuses 14

The Skull 15

Locomotion and Support Systems Vertebral Column Vertebral column Supports the head and trunk Protects the spinal cord and roots of spinal nerves Segments (from superior to inferior) Cervical - Neck Thoracic - Thorax Lumbar - Small of back Sacral - Sacrum Coccyx - Tailbone Intervertebral disks of fibrocartilage act as padding 16

Locomotion and Support Systems Rib Cage Protects the heart and lungs, and assists breathing Support by the thoracic vertebrae Twelve pairs of ribs True ribs w Connect w Seven directly to sternum pairs “False” ribs w Do not connect directly to sternum w Five pairs 17

The Rib Cage 18

Locomotion and Support Systems The Appendicular Skeleton Consists of The bones within the pectoral and pelvic girdles The attached limbs Pectoral girdle – Bones of the shoulder Anterior Supports the arms and hands Pelvic girdle - Bones of the pelvis Posterior Supports the legs and feet 19

Bones of the Pectoral Girdle, the Arm, and the Hand 20

Bones of the Pelvic Girdle, the leg, and the Foot 21

Locomotion and Support Systems Classification of Joints Fibrous Joints Immovable Between cranial bones Cartilaginous Joints Slightly Movable Between vertebrae Synovial Joints Freely Movable Bones separated by a cavity Ligaments bind bones together at joint 22

The Knee Joint 23

Locomotion and Support Systems 24 Human Muscular System Skeletal muscles Attached to the skeleton by cable-like fibrous connective tissue called tendons Arranged in antagonistic pairs Can only contract, cannot push When one muscle contracts, it stretches its antagonistic partner A muscle at “rest” exhibits tone (minimal contraction) A muscle in tetany is at maximum sustained contraction

Antagonistic Muscles 25