December 3, 2013 Name five bones in your body. Are bones living or dead? Explain. What is the function of bone marrow?
Skeletal, Muscular, and Integumentary Systems Chapter 36: Biology II
The Skeleton Supports the body Protects internal organs Humans have 206 bones!!! Provides for movement Site for blood cell formation
The Axial Skeleton Supports the central axis of the body Skull, vertebral column and rib cage
The Appendicular Skeleton Arms and legs, pelvis and shoulder area
Structure of Bones Solid networks of living cells and protein fibers Surrounded by deposits of calcium salts
Structure of Bones Compact bone Tough outer layer of bone Spongy bone Found beneath the layer of compact bone Adds strength without adding mass
Tough layer of connective tissue surrounding a bone Periosteum
Haversian Canal One of a network of tubes running through compact bone that contains blood vessels and nerves
Bone Cells Osteocytes Mature bone cells Osteoblasts Produce bone (osteocytes) Osteoclasts Break down bone Osteoblasts and osteoclasts line the Haversion canals & surfaces of compact and spongy bone
Bone Marrow Soft tissue inside cavities within bones Yellow Marrow Fat cells Red Marrow Produces red blood cells, white blood cells, platelets
Development of Bones Skeleton of a newborn baby is almost entirely cartilage Cartilage: strong connective tissue that supports the body Softer and more flexible than bone No blood vessels
Ossification Process of bone formation Osteoblasts secrete mineral deposits to replace cartilage When osteoblasts are surrounded by bone tissue they become osteocytes
December 4, 2013 What are the three types of bone cells and their functions? How does bone development occur? What are the types of bone marrow and their functions?
A place where one bone attaches to another bone Joint
Types of Joints Immovable/Fixed Joints: skull bones Slightly movable: bones of lower leg, between adjacent vertebrae Freely movable: movement in one or more directions
Freely Moveable Joints Ball-and-socket: circular movement Hinge: back and forth movement
Freely Moveable Joints Pivot: rotation of one bone around another Saddle: one bone can slide in two directions
Structure of Freely Movable Joints Ligament: strip of tough connective tissue in a joint that holds bones together
Structure of Freely Movable Joints Synovial fluid: a substance which forms a thin film within the bone surfaces of a joint Allows bones to slip past each other more smoothly
Structure of Freely Movable Joints Bursae: small sacs of synovial fluid that form in some freely-movable joints Reduce the friction between bones of a joint and act as a tiny shock absorber Bursitis: too much fluid fills the bursae, causing painful swelling more serious arthritis
Osteoporosis Effects mostly elderly women Loss of calcium in bones Weakens bones Can lead to serious fractures
December 5, 2013 List three types of freely moveable joints. What is an example of a fixed joint? What is the purpose of bursae? What happens with bursitis?
The Muscle System A skeleton cannot move by itself!
The Muscle System Muscles provide the forces that put the body into motion More than 40% of the mass of the average human is muscle
Types of Muscle Skeletal: attached to bones, responsible for voluntary movements Smooth: responsible for most involuntary movements Cardiac: found in the heart
Muscle Contraction Myofibrils: make up skeletal muscles Made of smaller structures called filaments (thick and thin) Myosin: protein that makes up the thick filaments in skeletal muscle cells Actin: protein that makes up the thin filaments in striations in skeletal muscle cells
Muscle Contraction A muscle contracts when actin filaments slide over myosin filaments Energy for muscle contraction is supplied by ATP Cellular respiration
Muscle Contraction Actin and myosin are arranged in units called sarcomeres. Each sarcomere is separated by a Z line
Muscle Contraction
Control of Muscle Contraction Motor neurons control muscle movements Neuromuscular junction Neuron secretes acetylcholine into synapse which triggers Ca 2+ to be released Ca 2+ release triggers the actin-myosin interactions
Control of Muscle Contraction Muscle stays contracted until release of acetylcholine stops which causes Ca 2+ release to stop
Muscles and Bones Skeletal muscles are joined to bones by tough connective tissue called tendons. Tendons pull on the bones and they work like levers. Muscles provide force to move the lever
December 9, 2013 What two fibers make up a myofibril? What are the three types of muscle and where are they found? Explain how muscle contraction occurs.
Integumentary System Integument means to cover in Latin This system includes the skin, hair, nails, and a variety of glands Serves as a barrier against injury and infection, helps regulate body temperature, protects against the sun, and removes waste products.
Skin Two main layers: Epidermis Dermis Beneath the dermis is the hypodermis Layer of fat and connective tissue that helps insulate the body
Skin Epidermis Outer layer of dead cells and an inner layer of living cells Keratin provides a tough, flexible waterproof covering on the skin surface Melanocytes produce melanin a dark brown pigment that absorbs UV rays. No blood vessels
Skin Dermis Contains collagen, blood vessels, nerve endings, glands, sensory receptors, smooth muscle, and hair follicles Sweat Glands Sebaceous glands Secretes oil called sebum to help keep epidermis flexible and waterproof
Hair and Nails Mostly made of keratin Hair Provides insulation & prevents dirt and other particles from entering eyes, ears, and nose Produced from hair follicles in the dermis Rapid cell growth at the follicle gives length to hair Follicles in close contact with sebaceous glands
Hair and Nails Nails Nail roots at the tip of each finger and toe have rapidly dividing cells that produce a tough, platelike nail filled with keratin. Grow at an average rate of 3 mm per month; fingernails grow four times as fast as toenails
December 10, 2013 What are sebaceous glands and why are they important? Explain the differences between the dermis and epidermis. What cells produce melanin and what is the function of melanin?