Muscular System Chapter 7 Pages 118 – 142

Functions of Muscular System Page 119 Functions of Muscular System Three main responsibilities: Body movement Body form and shape to maintain posture Body heat to maintain body temperature

Page 119 Types of Muscles Skeletal muscle – voluntary; Striated; Attached to bone Sarcolemma – cell membrane Sarcoplasm – cytoplasm Fascia – a band of muscular fibers (muscle cells) that envelops, separates, or binds muscles or groups of muscles Smooth muscle – involuntary; Non-striated; Controlled by the autonomic nervous system Cardiac muscle – In the heart only; Involuntary; Striated & branched Under conscious control (voluntary) Not under conscious control (involuntary) **** Sphincter muscles or dilator muscle are special circular muscles in the openings between the esophagus & stomach, & the stomach & small intestine. Found in the anus, the urethra, & the mouth

Characteristics of Muscles Page 120 Characteristics of Muscles Contractibility – Shorten in response to a stimuli Excitability (irritability) – the ability to respond to stimuli Action potentials – Electrical signals Extensibility – ability to be Stretched Elasticity – Return to original length when relaxing

Muscle Attachments & Functions Page 121 Muscle Attachments & Functions Over 650 muscles in the body Muscles must be attached to bones for leverage Muscles only pull, never push Attached to bone by tendons Muscles are attached at both ends Attachments may be to bones, cartilage, ligaments, tendons, skin, or to each other Origin and insertion Origin = the part of the of a skeletal muscle that is attached to a fixed structure or bone; it moves the least during muscle contraction Insertion = the other end, attached to a movable part; it is the part that moves most during a muscle contraciton

Muscle Attachments & Functions Pages 121 – 122 Muscle Attachments & Functions Prime mover – Movement in a single direction Antagonist – Pulls from the opposite direction Synergists – Steady the movement or stabilize the joint Muscles of the upper arm: Biceps – one end is attached to the scapula & humerus (its origin & remian stationary) other end attach to the radius of the lower arm (it’s insertion & moves when the muscle is flexed) Triceps is antagonist to the bicep

Sources of Energy & Heat Page 122 Sources of Energy & Heat Narrow range of normal body temperature (98.6° F to 99.8° F) Major source of energy is ATP (adenosine triphosphate) Production of ATP requires oxygen, glucose, & other materials By-product is lactic acid

Contraction of Skeletal Muscles Page 122 – 123 Contraction of Skeletal Muscles Movement of muscles is a result of two major events: Myoneural stimulation Stimulation by a nerve impulse causes contraction (muscle twitch) Motor unit consists of a nerve cell plus the muscle fiber it stimulates neuromuscular junction = junction between the nerve cell axon & the muscle cell membrane Contraction of muscle proteins Begins with an action potential Requires energy

Effects of Aging Page 123 SB Muscle atrophy Fibrous tissue replaces the muscle tissue Decrease in muscular strength & endurance Loss of energy storage (Fatigue)

Page 123 Muscle Fatigue Caused by accumulation of lactic acid in the muscles When not enough oxygen can be transported to oxidize all the glucose in the muscle Muscles contract anaerobically (without oxygen) Excess lactic acid causes fatigue & cramps Need to rest & repay oxygen debt to change the lactic acid back to glucose

Pages 123 – 124 Muscle Tone Muscle tone = slightly contracted & ready to pull. Achieved through proper nutrition & regular exercise Isotonic = When muscles contracts and shorten Isometric = When the tension increases but the muscle does not shorten Atrophy (weak & shrink from disuse) & hypertrophy (enlarged from over use)

Principle Skeletal Muscles Page 124 Principle Skeletal Muscles Skeletal or voluntary muscles = These move the skeleton Naming of Skeletal Muscles Named by Location, Size, Direction, Number of origins, Location of origin & insertion, & action Not all muscles are named by this method Also control movement of the eyeballs, eyelids, lips, tongue, & skin

Page 125 Muscles 656 muscles 327 antagonistic muscles & two unpaired muscles Orbicularis oris & Diaphragm Head muscles Neck muscles Trunk & extremity muscles

Muscles of the Head & Neck Page 125 Muscles of the Head & Neck Control expressions Mastication Movement of the head

Important to you

Trunk & Extremities Pages 126 – 130 Muscles of the upper extremities – Shoulder, arm, & hand movements Muscles of the trunk – Breathing & movement of the abdomen & pelvis Muscles of the lower extremities – Thigh, leg, ankle, foot, & toes

Page 129 Figure 7 – 11

Page 130 Figure 7 – 12

Page 131 Figure 7 – 13

Exercise Page 131 Alters the size, structure, & strength of a muscle Atrophy – Shrinking of muscle size Hypertrophy – Enlargement of muscle size Muscles can regenerate only to a limited degree If damage is extensive scars will form Improved coordination Improved respiratory & circulatory system Elimination or reduction of excess fat Improved joint movement

Training & Strength Pages 131 – 132 Increased Strength (capacity to do work) Increase in muscle size Improved antagonistic muscle coordination Improved functioning in the cortical brain region, where the nerve impulses that start muscular contraction originate

Message Muscles Page 132 – 134 Potential health benefits Terms used in massage therapy to describe type of massage Location of surface body muscles Physiotherapy and general massage Physiotherapy physical therapy

Electrical Stimulation Page 114 Electrical Stimulation Passing electrical currents through the skin into the body for therapeutic uses Stimulate nerve tissue Do not produce heat or cold Used in physical therapy

Intramuscular Injections Page 114 Intramuscular Injections Deltoid (upper arm) Vastus lateralis (anterior thigh) Dorsal gluteal or ventral gluteal (buttocks)

Musculoskeletal Disorders Page 134 Musculoskeletal Disorders Muscle atrophy – occur to muscles used infrequently Muscle strain – the overstretching or tearing of a muscle. A strain is less serious than a sprain. Muscle spasm (cramp) – a sustained contraction of the muscle Myalgia – a term used to describe muscle pain Dystonia – a condition characterized by involuntary muscle contractions that cause repetitive movements or abnormal pictures. The cause is unknown.

Musculoskeletal Disorders Page 134 – 135 Musculoskeletal Disorders Hernia – occurs when an organ protrudes through a weak muscle Flatfeet (talipes) – the arch of the foot is lower than normal Tetanus (lockjaw) – an infectous disease characterized by continuous spasms of the voluntary muscles. Torticollis (wry neck) – a condition in which the head becomes persistently turned to one side, often associated with painful muscle spasms

Musculoskeletal Disorders Page 135 Musculoskeletal Disorders Muscular dystrophy – a group of diseases in which the muscle cells deteriorate. Myastenia gravis – occurs when the connection between the nerves & muscle is lost. Heel spur – a calcium deposit in the plantar fascia near its attachment to the calcaneus bone can cause plantar fasciitis Plantar fasciitis – inflammation of the plantar fascia on the sole of the foot

Recreational Injuries Page 136 Recreational Injuries Tennis elbow – the tendon that connects the arm muscles to the elbow becomes inflamed because of repetitive use of the arm & underconditioning Shin splints – injury to the muscle tendon in the front of he shin (usually from jogging) Rotator cuff injury – inflammation of a group of tendons that act together to stabilize the shoulder joint.

Chapter 7 Treatment Short-term treatment for sprains, tears, pulls, & other minor muscle or joint injuries RICE R = Rest I = Ice C = Compression E = Elevation