Chapter 15 Skeletal, Muscular, and Nervous Systems

Skeletal System Functions What role does the skeletal system play for our bodies? Structure Types of bones Types of joints Cartilage Care of What can we eat and drink to build strong bones? Problems of Fractures Osteoporosis Scoliosis Joint Injuries Repetitive Motion Injury

Functions of the Skeletal System Support upper body and head Provides strong, stable framework on which muscles can act Protects internal tissues and organs Bones store minerals needed for strong skeleton and other essential processes in the body Bone marrow produces new red and white blood cells

Structure of the Skeleton: Skeletal Groups 206 bones in the body split into two main groups Axial skeleton: 80 bones of the skull, spine, ribs, vertebrae, and sternum Appendicular skeleton: 126 bones of the upper/lower limbs, shoulders and hips

Structure of the Skeleton: Types of Bones All bones have compact bone (hard, densely packed) on the outside and spongy bone (less dense with cavities filled with bone marrow) on the inside Bones are categorized by shape Long bones Short bones Flat bones Irregular bones

Long Bones Diaphysis is the main column of a long bone Epiphysis is the end of a long bone Examples: femur, humerus, tibia, fibula, ulna, radius

Short Bones Almost equal in length and width Examples: carpals, tarsals, patella

Flat Bones Somewhat thinner and much flatter than other bones Examples: skull, scapula, ribs, sternum, hip bones

Irregular Bones Unusual shapes and do not fall into other categories Examples: facial bones, vertebrae

Cartilage Strong, flexible connective tissue Acts as a cushion, reducing friction and allowing smooth motion As an embryo, we are made up of mostly cartilage Ossification occurs in which the cartilage hardens and bones are formed, renewed, and repaired

Joints Ball and socket joint: rounded head of one bone fits into rounded cavity of an adjoining bone Allow widest range of movement in all directions Example: hip, shoulder joint Hinge joint Allow a joint to bend and straighten, promoting rotation Example: elbow, knee, ankle, fingers Pivot joint Allow limited rotation or turning of the head Ellipsoidal joint: oval-shaped part that fits into a curved space Allow bones to slide over one another

Joints Ball and Socket Joint Hinge Joint

What holds them all together? Ligaments: connective tissues that attaches bone to bone Stabilizes the movements of bones at a joint Tendon: fibrous cord that attached muscle to bone Movement is produced because muscles are attached to bones by tendons and ligaments

Care of the Skeletal System What we eat/drink Foods that contain calcium, vitamin D, and phosphorus Dairy products, beans, whole grains, green leafy vegetables What we do Regular physical activity Wearing protective gear

Problems of the Skeletal System: Fractures Fracture: any break in a bone Compound fracture: broken end of bone protrudes through skin Simple fracture: bone does not protrude Hairline fracture: fracture is incomplete, and two parts of the bone did not separate Transverse fracture: fracture complete across bone Comminuted fracture: bone shatters into more than two pieces

Problems of the Skeletal System Osteoporosis: condition in which progressive loss of bone tissue occurs Bones are weak and brittle, causing them to break easily Scoliosis: lateral curvature of the spine Can exist at birth or develop during childhood Treatment consists of wearing a brace to help straighten the spine Repetitive Motion Injury: damage to tissues caused by prolonged, repetitive movements (assembly line work, computer work, tennis swing)

Problems of the Skeletal System: Joint Injuries Dislocation: results when ligaments that attach to bone are born as the bone slips out of place Torn cartilage: resulting from sharp blow or twisting of a joint Bursitis: inflammation of a fluid-filled sac called the bursa Bunion: painful swelling of the bursa in the first joint of the big toe Arthritis: inflammation of a joint

Muscular System Functions What role does it play for our body? Structure Types of muscle Care of Problems of

Functions of the Muscular System Certain muscles are being used at all times in your body Muscles are used when sleeping, eating, breathing, etc. These processes are involuntary and happen without us consciously controlling them Our body would not be able to perform any activities without the use of voluntary or involuntary muscles

Structure of the Muscular System Muscles work by means of two complementary, or opposing, actions Contraction: shortening of a muscle Extension: stretching of a muscle Three types of muscle Smooth muscle: act on the lining of the passageways and internal organs Involuntary control Found in lining of blood vessels, digestive tract, passageways that lead into lungs, and bladder Skeletal muscle: attached to bone and cause body movements Voluntary control Typically two muscles work together, undergoing opposite actions to produce movement Flexor: muscle that closes a joint Extensor: muscle that opens a joint Cardiac muscle: type of striated muscle that forms the wall of the heart Involuntary control Responsible for contraction of your heart

Care of the Muscular System Regular physical activity is the best way to keep muscles strong and healthy This will also keep muscles toned and healthy Muscles unused over a long period of time will atrophy (decrease in size and length)

Problems of the Muscular System Bruise: area of discolored skin that appears after an injury causes blood vessels beneath the skin to rupture and leak Muscle strain: stretched or partially torn as result of overexertion Muscle sprain: injury to the ligament in a joint Tendonitis: inflammation of a tendon caused by injury, overuse, or aging Hernia: organ or tissue protrudes through an area of weak muscle Muscular dystrophy: inherited disorder in which skeletal muscle fibers are progressively destroyed

Nervous System Function Transmit message back and forth between every organ, tissue, and cell Structure Two main divisions Neurons Central Nervous System Peripheral Nervous System

Functions of Nervous System Coordinates all of the activities in your body Nerves transmit messages back and forth to every organ, tissue, and cell Two main divisions: Central Nervous System (CNS) Consists of the brain and spinal cord Receives messages from the nerves in the PNS, interprets them and sends out response Peripheral Nervous System (PNS) Includes nerves that extend from the brain, spinal cord, and sensory receptors Gathers information from inside and outside the body and sends messages to the CNS

Structure of the Nervous System Neurons (nerve cells): messengers that transmits to and from the spinal cord and brain Classified by their function: sensory neuron, motor neuron, and interneuron Neuron consists of three main parts: Cell body: contains nucleus (control center of cell), regulates production of proteins within the cell Dendrites: branched structures that extend from cell body, receive information from other neurons and transmits impulses toward cell body Axons: transmit impulses away from cell body and toward anther neuron Axon terminal: branches of the axon Myelin Sheath: surrounds the axon and facilitates in transmission of nerve impulses Neurotransmitters: chemical messengers

Central Nervous System Spinal Cord: long column of nerve tissue about the thickness of the index finger extending down your back Vertebrae: bones that make up your spine Cerebrum: largest and most complex part of the brain, center for conscious thought, learning, and memory Cerebellum: second largest part of the brain, coordinates the movement of the skeletal system Brain Stem: stalk of nerve cells and fibers that connects the spinal cord to the rest of the brain

Peripheral Nervous System Carries messages between the CNS and the rest of the body Divided into two categories Autonomic Nervous System Controls involuntary functions such as digestion and heart rate During periods of rest and relaxation, it slows down your heartbeat and lowers blood pressure In control of the “flight or fight” response and reflexes Somatic Nervous System Relays messages from receptors in the eyes, ear, nose, tongue, and skin to the CNS Motor neurons that carry impulses from the CNS to skeletal muscle

Candy Neuron!!! AND Candy CNS and PNS!!!