33 1 Skeletal System KEY CONCEPT The skeletal

33. 1 Skeletal System KEY CONCEPT The skeletal system includes bones and tissues that are important for supporting, protecting, and moving your body.

33. 1 Skeletal System Your skeletal system is made up of the appendicular and axial skeletons. • The skeletal system protects, supports, and moves the body.

33. 1 Skeletal System • The appendicular skeleton includes legs, arms, feet and hands. – allows for movement – includes bones called girdles that connect limbs to body

33. 1 Skeletal System • The axial skeleton includes the skull, rib cage, and spinal column. – supports body and protects skull tissues – allows for limited movement rib breastbone vertebra

33. 1 Skeletal System • Cartilage is connective tissue between bones. – cushions bones – allows for smooth movement – connect two bones cartilage

33. 1 Skeletal System Bones connect to form joints. • Joints are places were two bones meet. • There are three types of joints. – fibrous, which does not fibrous joint allow for movement

33. 1 Skeletal System Bones connect to form joints. • Joints are places were two bones meet. • There are three types of joints. – cartilaginous, which allows partial movement cartillage

33. 1 Skeletal System Bones connect to form joints. • Joints are places were two bones meet. • There are three types of joints. – synovial, which allows for greater movement

33. 1 Skeletal System • Ligaments are long bands of tissue that connect bones across a joint. ligament

33. 1 Skeletal System • There are several types of synovial joints. – gliding – pivot GLIDING JOINT – ball-and-socket PIVOT JOINT – saddle BALL-AND-SOCKET JOINT – hinge SADDLE JOINT HINGE JOINT

33. 1 Skeletal System Bones are living tissue. • Bone is made of compact bone tissue and spongy bone tissue. Compact bone Spongy bone

33. 1 Skeletal System • Compact bone is hard and dense. – Osteocytes (bone cells) maintain compact bone rings. – Haversian canals allow blood vessels in the bone. osteocytes blood vessel Haversian canals

33. 1 Skeletal System • 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

33. 1 Skeletal System • Calcification is the process of building hard bone. – combines collagen and calcium phosphate – transforms cartilage into hard bone during childhood osteocyte compact bone

33. 1 Skeletal System KEY CONCEPT 33. 2 Muscles are tissues that can contract, enabling movement.

33. 1 Skeletal System 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

33. 1 Skeletal System • There are three types of muscle tissue. – skeletal muscle – smooth muscle – cardiac muscle SKELETAL MUSCLE SMOOTH MUSCLE CARDIAC MUSCLE

33. 1 Skeletal System • Skeletal muscle attaches to the skeleton by tendons. – Tendons connect muscle to bone. – Skeletal muscles are mostly voluntary. SKELETAL MUSCLE

33. 1 Skeletal System • 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

33. 1 Skeletal System • Cardiac muscle is found only in the heart. – pumps blood throughout body – controlled by pacemaker – contains more mitochondria than skeletal muscle cells CARDIAC MUSCLE

33. 1 Skeletal System Muscles contract when the nervous systems causes muscle filaments to move. • Muscle fibers are cells of the muscular system. muscle fiber muscle

33. 1 Skeletal System • Myofibrils are long strands of protein in the muscle fiber. myofibril muscle fiber muscle

33. 1 Skeletal System • Each myofibril is divided into sarcomeres. • Sarcomeres contain filaments that cause contraction. muscle fiber myofibril sarcomere muscle

33. 1 Skeletal System • Each myofibril is divided into sarcomeres. • Sarcomeres contain filaments that cause contraction. – Actin filaments are pulled during contraction. – Myosin filaments pull actin during contraction. RELAXATION M line CONTRACTION myosin Z line

33. 1 Skeletal System • Neuron stimulates muscle at the neuromuscular junction neuron MUSCLE

33. 1 Skeletal System • Neuron stimulates muscle at the neuromuscular junction. – Neurotransmitters cause calcium regulatory protein channels in the sarcomere to open. – Calcium exposes binding sites. – Myosin binds to actin and pulls it. – As the sarcomere shortens, the muscle contracts. actin myosin Z line

33. 1 Skeletal System KEY CONCEPT 33. 3 The integumentary system has many tissues that protect the body.

33. 1 Skeletal System The integumentary system helps maintain homeostasis. • The integument is the body system that surrounds all your other organ systems.

33. 1 Skeletal System The integumentary system helps maintain homeostasis. • The integumentary system consists of many parts. – skin – hair – nails – oil glands – sweat glands – proteins, such as keratin

33. 1 Skeletal System • Integumentary system removes substances from the body. – water – salts – urea pore sweat glands

33. 1 Skeletal System The integumentary system consists of many different tissues. • The outermost layer of the skin is the epidermis. – dead skin cells – oils epidermis – pores pore

33. 1 Skeletal System • Cells in the epidermis produce keratin and melanin. – Keratin makes cells waterproof and tough feeling. – Melanin is a dark pigment that absorbs UV rays.

33. 1 Skeletal System • The dermis contains most of the tissues in the skin. – sweat glands – oil glands – pressure receptors – blood vessels – hair follicles hair follicle oil gland dermis pressure receptors sweat gland

33. 1 Skeletal System • 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.

33. 1 Skeletal System • Beneath the dermis is a layer of fat layer