Unit 3.5 The Skeletal & Muscular Systems

Functions of Bones  Support of the body  Protection of soft organs  Movement due to attached skeletal muscles  Storage of minerals and fats  Blood cell formation

Types of Bones Human skeleton has 206 bones

Microscopic Anatomy of Bone

Types of Bone Cells  Osteocytes  Mature bone cells  Osteoblasts  Bone-forming cells  Osteoclasts  Bone-destroying cells

Stages in the Healing of a Bone Fracture

The Axial Skeleton  Forms the longitudinal part of the body  Divided into three parts  Skull  Vertebral column  Bony thorax

The Skull  Two sets of bones  Cranium  Facial bones  Bones are joined by fused joints  Only the mandible is attached by a freely movable joint

The Skull

Bones of the Skull

The Fetal Skull  The fetal skull is large compared to the infants total body length  Gaps allow the brain to grow over the next 2 years

The Vertebral Column  Cervical vertebrae comprise the neck - 7  Thoracic vertebrae have ribs growing off of them - 12  Lumbar vertebrae comprise the lower back - 5

The Bony Thorax  Forms a cage to protect major organs  Made-up of three parts  Sternum  Ribs  Thoracic vertebrae

The Appendicular Skeleton  Limbs (appendages)  Pectoral girdle  Pelvic girdle

The Pectoral Girdle  Composed of two bones  Clavicle – collarbone  Scapula – shoulder blade  Allow arms to have exceptionally free movement

Bones of the Upper Limb  The arm is formed by a single bone  Humorous

Bones of the Upper Limb The forearm has two bones Ulna – pinky side Radius – thumb side

Bones of the Upper Limb  The hand  Carpals – wrist  Metacarpals – palm  Phalanges – fingers

Bones of the Pelvic Girdle  Hip bones  Composed of three pair of fused bones  Ilium  Ischium  Pubic bone

Bones of the Lower Limbs  The thigh has one bone  Femur – thigh bone

Bones of the Lower Limbs  The leg has two bones  Tibia – front leg  Fibula – back leg

Bones of the Lower Limbs  The foot  Tarsals – ankle  Metatarsals – sole  Phalanges – toes

The Muscular System  Three basic muscle types are found in the body  Smooth muscle  Cardiac muscle  Skeletal muscle

Smooth Muscle Characteristics  Involuntary – no conscious control  Found mainly in the walls of hollow organs  Also line blood vessels  Slow, sustained and tireless

Cardiac Muscle Characteristics  Involuntary  Found only in the heart  Beat 100,000 times a day, 35 million times a year, and over 2.5 billion times in a lifetime

Skeletal Muscle Characteristics  Produce movement  Maintain posture  Stabilize joints  Generate heat

The Sliding Filament Theory

Ventral Trunk Muscles

Dorsal Trunk Muscles

Muscles of the Pelvis, Hip, and Thigh

Muscles of the Lower Leg