Skeletal, Muscular, & Nervous System Chapter 15

Functions of the skeletal system Provides a living structure for your body Supports your upper body and head Plays a crucial role in movement Protects internal tissues and organs from trauma Store minerals

Structure of the skeleton You have 206 bones in your body Axial Skeleton – the 80 bones of the skull, spine, ribs, vertebrae, and sternum or breastbone Appendicular skeleton – the remaining 126 bones of the upper and lower limbs, shoulders, and hips

Types of bones Long Bones – your arms and legs Humerus is the bone in your upper arm Diaphysis main column of a long bone Epiphysis is the end of a long bone

Types of bones Short Bones – are almost equal in length and width Small bones in the wrist & ankles

Types of bones Flat Bones – somewhat thinner and much flatter than other bones The skull, scapula, or shoulder blade are all examples

Types of bones Irregular Bones – are irregularly shaped Some facial bones & vertebrae are examples

Cartilage Cartilage – a strong, flexible connective tissue Found at the ends of long bones End of the nose Within the outer ear In some joints like the knee & acts like a cushion

Cartilage Ossification – is the process by which bone is formed, renewed, & repaired This happens early in the embryonic developmental stage

Joints Joints are points at which bones meet

Types of Joints Ball-&-socket joint – formed when the rounded head of one bone fits into the rounded cavity of an adjoining bone Hinge joint – found at the elbow, knee, ankle & fingers Pivot joints – allow limited rotation or turning of the head

Types of Joints Ellipsoidal joints – such as the ones in your wrist, have an oval-shaped part that fits into a curved space Ligament – a band of fibrous, slightly elastic connective tissue that attaches bone to bone Tendon – a fibrous cord that attaches muscle to the bone

Care & Problems of the Skeletal System Lesson 2

Problems of the skeletal system Fractures – any type of break in a bone They can be either compound or simple Compound – one in which the broken bones protrudes through the skin Simple – one in which the broken bone does not protrude

Types of Fractures Hairline fracture –the fracture is incomplete & the two parts of the bones do not separate Transverse fracture – the fracture is completely across the bone Comminuted fracture – the bone shatters into more than 2 pieces

Osteoporosis You can only develop bone now while you are growing. Your habits now will affect you later in life Osteoporosis – a condition in which progressive loss of bone tissue occurs Usually affects millions of older Americans & has no warning signs

Scoliosis Scoliosis – is a lateral, or side-to-side, curvature of the spine This may exist at the time of birth, or it can develop during childhood Treatments include wearing braces to help straighten the spine and possibly even surgery in severe cases

Injuries to Joints Dislocation – results when the ligaments that attach the bone at the joint are torn as the bone slips out of place Torn cartilage – can result from a sharp blow or the twisting of a joint Bursitis – results from the inflammation of a fluid-filled sac called the bursa

Injuries to Joints Bunion – is a painful swelling of the bursa in the first joint of the big toe Arthritis – is the inflammation of a joint Repetitive motion injury – is damage to tissue caused by prolonged, repeated movements such as in computer work, sewing or assembly line work

The Muscular System Lesson 3

Functions of the muscular system Help you to breathe, make your heart beat, and move food through your digestive system Voluntary muscles – muscles you knowingly move Involuntary muscles – muscles that move without your conscious control

Structure of the Muscular System Muscles are made up of hundreds of long cells called fibers Muscles work by means of two complementary or opposing actions Contraction – shortening of the muscles Extension – lengthening of the muscles

Types of Muscles Smooth muscles – act on the lining of passageways and internal organs (they are involuntary) Skeletal Muscles – are attached to bone and cause body movements (they are voluntary) Flexor – the muscle that close a joint Extensor – the muscle that opens a joint

Types of Muscles Cardiac muscles – a type of striated muscle that forms the wall of the heart (it is an involuntary muscle)

Care of the Muscular System Muscle tone – the natural tension in the fibers of a muscle Regular physical activity can help to keep your muscles toned

Problems of the Muscular System Bruise – is an area of discolored skin that appears after an injury causes the blood vessels beneath the skin to rupture and leak Muscle sprain or strain – a strained muscles results when a muscle is stretched or partially torn as a result of overexertion

Problems of the Muscular System Muscles strains are treated using the Rest Ice Compression Elevation Or RICE method

Problems of the Muscular System Tendonitis – or the inflammation of a tendon Caused by injury, overuse, or natural aging Hernia – when an organ or tissue protrudes through an area of weak muscle

Problems of the Muscular System Muscular Dystrophy – is an inherited disorder in which skeletal muscle fibers are progressively destroyed

The Nervous System Lesson 4

Functions of the nervous system It coordinates all of the activities in your body including Breathing Or digesting food to sensing pain or feeling fear

Functions of the nervous system The brain, spinal cord, and nerves all work together The nervous system has 2 main divisions Central Nervous System Peripheral Nervous System

Functions of the nervous system Central Nervous System – consists of the brain and spinal cord Peripheral Nervous System – gathers information from inside and outside your body

Neurons Neurons – are nerve cells

Neurons Cell body – the cell body of a neuron contains the nucleus, the control center of the cell Neuron cells have limited ability to repair damage or replace destroyed cells

Neurons Dendrites – are branched structures that extend from the cell body in most neurons They receive information from other neurons or sensory receptors and transmit impulses toward the cell body

Neurons Axons – transmit impulses away from the cell body and toward another neuron, muscle cell, or gland Axons that are covered by a myelin sheath can transmit impulses faster than those without a cover

Central Nervous System Parts of the central nervous system include the spinal cord & the brain Brain – the main job of the brain is to integrate & control the activities of the nervous system

Parts of the brain Cerebrum – the largest and most complex part of the brain, its job is to focus on thought, learning and memory Frontal lobe – controls voluntary movements & has a role in the use of language Parietal lobe – is involved with sensory information such as heat, cold, pain, touch a, & body position

Parts of the brain Occipital lobe – controls the sense of vision Temporal lobe – controls the senses of hearing & smell; it is also involved with memory, thought, and judgment

Parts of the brain Cerebellum – the second largest part of the brain, its job is to coordinate the movement of skeletal muscles

Parts of the brain Brain stem – is a 3” stalk of nerve cells & fibers that connects the spinal cord to the rest of the brain Medulla oblongata – is the lowest part of the brain stem, helps to regulate heartbeat & respiratory rate as well as reflexes such as sneezing, coughing, & vomiting

Medulla oblongata Has 3 parts to it Pons – located just above the medulla. This is the pathway connecting nerve impulses to other areas of the brain. Helps regulate breathing Midbrain – the highest portion of the brain stem. Controls eyeball movement

Medulla oblongata Thalamus – an important relay center for incoming sensory impulses. Receives information through the eyes and the ears Hypothalamus – controls balance and various body processes to regulate body temperature, appetite awareness, and regulates sleep Pituitary gland – controls metabolism, sexual development & emotional responses

The Peripheral Nervous System Includes all the nerves that are not part of the Central Nervous System (CNS) The Peripheral Nervous System can be divided into 2 parts Autonomic Nervous System Somatic Nervous System

Autonomic Nervous System Controls involuntary actions such as digestion & heart rate The Autonomic nervous system is broken down into 2 parts Sympathetic nervous system Parasympathetic nervous system

Sympathetic nervous system Cause your heart rate to increase and blood vessels leading to your muscles to dilate Reflex – s spontaneous response of the body to a stimulus

Parasympathetic nervous system During rest it opposes the actions of the sympathetic system by slowing body functions Slows down heartbeats, opens blood vessels, and lowers blood pressure

Somatic Nervous System Consists of sensory neurons that relay messages from receptors in the eyes, ear, nose, tongue, & skin to the CNS & motor neurons that carry impulses from the CNS to the skeletal muscles

Care & Problems of the Nervous System Lesson 5

Problems of the Nervous System Drug & alcohol use can destroy brain cells & cause nervous system disorders

Degenerative Disease Parkinson’s Disease – is the destruction of nerve cells in an area of the brain that helps coordinate skeletal muscle movement Multiple Sclerosis – the destruction of the myelin sheath that surrounds the axons of neurons in the CNS. Voluntary control of your muscles gradually decreases. The body basically attacks its own tissues

Degenerative Disease Alzheimer’s Disease – when neurons are destroyed. They are then unable to transmit impulses. Resulting in loss of memory & confusion

Other disorders & problems Epilepsy – a disorder of the nervous system that is characterized by recurrent seizures Cerebral palsy – a group of nonprogressive neurological disorders that are the result of damage to the brain before, during, or just after birth or in early childhood