KEY CONCEPT The skeletal system includes bones and tissues that are important for supporting, protecting, and moving your body.

Your skeletal system is made up of the appendicular and axial skeletons. The skeletal system protects, supports, and moves the body.

The appendicular skeleton includes legs, arms, feet and hands. allows for movement includes bones called girdles that connect limbs to body

The axial skeleton includes the skull, rib cage, and spinal column. supports body and protects tissues allows for limited movement skull rib breastbone vertebra

Cartilage is connective tissue between bones. cushions bones allows for smooth movement connect two bones cartilage

Bones connect to form joints. Joints are places were two bones meet. There are three types of joints. fibrous, which does not allow for movement fibrous joint

Bones connect to form joints. Joints are places were two bones meet. There are three types of joints. cartilaginous, which allows partial movement cartillage

Bones connect to form joints. Joints are places were two bones meet. There are three types of joints. synovial, which allows for greater movement

Ligaments are long bands of tissue that connect bones across a joint.

There are several types of synovial joints. gliding pivot ball-and-socket saddle hinge GLIDING JOINT PIVOT JOINT BALL-AND-SOCKET JOINT SADDLE JOINT HINGE JOINT

Bones are living tissue. Bone is made of compact bone tissue and spongy bone tissue. Compact bone Spongy bone

Compact bone is hard and dense. Osteocytes (bone cells) maintain compact bone rings. Haversian canals allow blood vessels in the bone. blood vessel osteocytes Haversian canals

Spongy bone protects red or yellow bone marrow. Red bone marrow produces blood cells. Yellow bone marrow is mostly fat. Periosteum A layer of connective tissue that covers bone Red bone marrow

Calcification is the process of building hard bone. combines collagen and calcium phosphate transforms cartilage into hard bone during childhood osteocyte compact bone

KEY CONCEPT 33.2 Muscles are tissues that can contract, enabling movement.

Humans have three types of muscle. The muscular system moves substances throughout the body. bones of the skeletal system food through digestive system blood through circulatory system fluids through excretory system

There are three types of muscle tissue. skeletal muscle smooth muscle cardiac muscle SKELETAL MUSCLE SMOOTH MUSCLE CARDIAC MUSCLE

Skeletal muscle attaches to the skeleton by tendons. Tendons connect muscle to bone. Skeletal muscles are mostly voluntary. SKELETAL MUSCLE

Smooth muscle lines organs and is involuntary. move food through digestive organs empty liquid from the bladder control width of blood vessels Smooth muscle around this artery allows the artery to regulate blood flow by shrinking and expanding. SMOOTH MUSCLE

Cardiac muscle is found only in the heart. pumps blood throughout body controlled by pacemaker contains more mitochondria than skeletal muscle cells CARDIAC MUSCLE

Muscle fibers are cells of the muscular system. Muscles contract when the nervous systems causes muscle filaments to move. Muscle fibers are cells of the muscular system. muscle muscle fiber

Myofibrils are long strands of protein in the muscle fiber.

Each myofibril is divided into sarcomeres. Sarcomeres contain filaments that cause contraction. myofibril muscle fiber muscle sarcomere

Each myofibril is divided into sarcomeres. Sarcomeres contain filaments that cause contraction. Actin filaments are pulled during contraction. Myosin filaments pull actin during contraction. CONTRACTION RELAXATION M line myosin Z line

Neuron stimulates muscle at the neuromuscular junction.

Neuron stimulates muscle at the neuromuscular junction. Neurotransmitters cause calcium channels in the sarcomere to open. regulatory protein Calcium exposes binding sites. Myosin binds to actin and pulls it. As the sarcomere shortens, the muscle contracts. myosin actin Z line

KEY CONCEPT 33.3 The integumentary system has many tissues that protect the body.

The integumentary system helps maintain homeostasis. The integument is the body system that surrounds all your other organ systems.

The integumentary system helps maintain homeostasis. The integumentary system consists of many parts. skin hair nails oil glands sweat glands proteins, such as keratin

Integumentary system removes substances from the body. water salts urea pore sweat glands

The integumentary system consists of many different tissues. The outermost layer of the skin is the epidermis. dead skin cells oils pores epidermis pore

Cells in the epidermis produce keratin and melanin. Keratin makes cells waterproof and tough feeling. Melanin is a dark pigment that absorbs UV rays.

The dermis contains most of the tissues in the skin. sweat glands oil glands pressure receptors blood vessels hair follicles dermis hair follicle oil gland pressure receptors sweat gland

A hair follicle is pit of cells that produces hair. The dermis also produces elastin and collagen. Elastin makes skin flexible. Collagen gives skin its shape.

Beneath the dermis is a layer of fat. fat layer