Muscular System Objective 1 04 The Muscular System

Muscular System Objective 1. 04

The Muscular System • Comprises nearly half our weight. • Over 650 muscles. • Each muscle is made up of hundreds or thousands of muscle fibers. 1. 04 Remember the structures of the muscular system 2

The Muscular System: Muscle Fibers • Bundles of threadlike structures called myofibrils – Composed of: • Myosin • Actin – Form overlapping pattern called sarcomere muscle fiber sarcolemma sarcomere functional unit of muscle movement 1. 04 Remember the structures of the muscular system 3

Structures of the muscular system Muscles Connective tissue § Skeletal § Tendons § Smooth § Fascia § Cardiac § Sphincter 1. 04 Remember the structures of the muscular system 4

Structures of the muscular system Types of Muscle Skeletal muscles § Attached to bone § Striated (striped) appearance § Voluntary § Multinucleated muscle cell bundles 1. 04 Remember the structures of the muscular system 5

Structures of the muscular system Types of Muscle Smooth muscles § Also known as visceral muscles § Involuntary § Located in walls of digestive system, uterus & blood vessels 1. 04 Remember the structures of the muscular system 6

Structures of the muscular system Types of Muscle Cardiac muscle § § Found only in the heart Striated, branched Involuntary Cells are fused- when one contracts, they all contract, creating the heartbeat 1. 04 Remember the structures of the muscular system 7

Structures of the muscular system Types of Muscle Sphincter muscles § § § Also called dilator muscles Special, circular muscles Located in the § digestive system § urinary system 1. 04 Remember the structures of the muscular system 8

Structures of the muscular system Types of Muscle § Skeletal § Smooth § Cardiac § Sphincter 1. 04 Remember the structures of the muscular system 9

Structures of the muscular system Connective tissue § Tendons dense bands that connect skeletal muscle to the bone 1. 04 Remember the structures of the muscular system 10

Structures of the muscular system Connective tissue § Fascia Fibrous connective tissue sheets that wrap around muscle bundles 1. 04 Remember the structures of the muscular system 11

How do skeletal muscles get their names? • Location • Size • Location of origin and insertion • Direction • Action flexor • Number of origins • Extensor • Depressor • However, not all muscles are named by the above methods! 1. 04 Remember the structures of the muscular system 12

Head & Neck Muscles 1. 04 Remember the structures of the muscular system 13

Torso/Trunk (anterior) 1. 04 Remember the structures of the muscular system 14

Torso/Trunk (anterior) 1. 04 Remember the structures of the muscular system 15

Torso/Trunk (posterior) 1. 04 Remember the structures of the muscular system 16

Upper extremities 1. 04 Remember the structures of the muscular system 17

Lower extremities 1. 04 Remember the structures of the muscular system 18

The muscular system review Anterior view 1. 04 Remember the structures of the muscular system 19

The muscular system review Posterior view 1. 04 Remember the structures of the muscular system 20

Characteristics of Muscles Contractibility Excitability Extensibility Elasticity 1. 05 Understand the functions and disorders of the muscular system 21

Characteristics of Muscles Contractibility 1. 05 Understand the functions and disorders of the muscular system 22

Characteristics of Muscles Contractibility Myoneural stimulation + contraction of muscle proteins = movement and heat 1. 05 Understand the functions and disorders of the muscular system 23

Characteristics of Muscles Excitability 1. 05 Understand the functions and disorders of the muscular system 24

Characteristics of Muscles Extensibility 1. 05 Understand the functions and disorders of the muscular system 25

Characteristics of Muscles Elasticity 1. 05 Understand the functions and disorders of the muscular system 26

Characteristics of Muscles Contractibility Excitability Extensibility Elasticity 1. 05 Understand the functions and disorders of the muscular system 27

Characteristics of Muscles Contractibility 1. 05 Understand the functions and disorders of the muscular system 28

Characteristics of Muscles Contractibility Myoneural stimulation + contraction of muscle proteins = movement and heat (side effect) 1. 05 Understand the functions and disorders of the muscular system 29

Characteristics of Muscles Contractibility Neurotransmitter at site of muscle stimulus. The sodium-potassium pump of the membrane of a muscle cell. The purpose of this slide is to illustrate the complexity of the process of movement. 1. 05 Understand the functions and disorders of the muscular system 30

Muscle Tone Discuss muscle tone. • Atrophy: a- ____ -trophy _nourishment / development___ • Hypertrophy: hyper- _______ -trophy _nourishment / development__ 1. 05 Understand the functions and disorders of the muscular system 31

Muscle Tone John just got a cast off his leg. His calf muscle on the affected leg is 1” smaller in diameter than his other calf muscle. • What happened? • How do you explain this to him? 1. 05 Understand the functions and disorders of the muscular system 32

Muscle Fatigue Discuss muscle fatigue: – What causes muscle fatigue? – How does the body correct muscle fatigue? – Is muscle fatigue dangerous? Why / why not? – Discuss aerobic and anaerobic exercise. • Give examples of each. 1. 05 Understand the functions and disorders of the muscular system 33

Functions of the Muscular System What are the functions of the muscular system? 1. 05 Understand the functions and disorders of the muscular system 34

Movement: Skeletal Muscle • Receptors in muscles provide the brain with information about body position and movement. • The brain controls the contraction of skeletal muscle. 1. 05 Understand the functions and disorders of the muscular system 35

Movement As your muscle contracts, one of the bones will move with the other will remain stationary. Point of origin (end of the muscle that is attached to the stationary bone) Point of insertion (end of muscle that is attached to the moving bone) Prime mover or agonist Antagonist – muscles that cause movement in the opposite direction Synergists – assist primary mover All movement is a result of contraction of primary movers and relaxation of opposing muscles.

Movement: Digestive System The nervous system regulates the speed at which food moves through the digestive tract. 1. 05 Understand the functions and disorders of the muscular system 37

Movement: Circulatory System Heartbeat The nervous system and hormones regulate the speed at which the heart beats. 1. 05 Understand the functions and disorders of the muscular system 38

Posture • How does the muscular system effect posture? 1. 05 Understand the functions and disorders of the muscular system 39

Body Heat What is the body’s response to cold? Why? How is this response helpful? How does the body respond to exercise? Why? 1. 05 Understand the functions and disorders of the muscular system 40

Fibromyalgia Discuss the pictures and how they relate to fibromyalgia. Cause - unknown Symptoms – chronic pain, fatigue, depression Diagnosis – location of pain Treatment – symptom mgt Prognosis – good…management 1. 05 Understand the functions and disorders of the muscular system 41

Hernia Weakness in the muscles of the abdominal wall that allows loops of intestine to balloon outward Causes – muscle weakness, excessive internal pressure Locations – groin, abd Symptoms – protrusion, pain Diagnosis – palpation, mri Treatment - surgery Prevention – abd exercises 42

Muscle Spasms (Involuntary hypertonicity) Symptoms – severe pain Diagnosis – hx, physical exam Treatment – rest, stretching, exercise Prognosis - good 1. 05 Understand the functions and disorders of the muscular system 43

Muscular Dystrophy Cause – genetic defect…progressive weakness and degeneration of skeletal muscle Symptoms – muscle weakness, drooling, falling, eyelid drooping (ptosis) Diagnosis – physical exam, genetic test Treatment – no treatment to stop or reverse MD…treat symptoms Prognosis - variable 44

Myasthenia Gravis Cause - Autoimmune attack at neuromuscular junction…affects voluntary muscles…problem with how nerves stimulate muscles to contract Symptoms – progressive, fluctuating muscle weakness and fatigue Diagnosis – blood tests, EMG Treatment – steroids, immunosuppressant drugs Prognosis – with treatment may lead a normal, active life…remission possible 1. 05 Understand the functions and disorders of the muscular system 45

Strain • Overstretching of the tendons or the muscles themselves (“pulled muscle”). • Treatment = RICE 1. 05 Understand the functions and disorders of the muscular system 46

Tendonitis • Usually from chronic injury, overuse • Pain and inflammation are common • Treatment = (P)RICE 1. 05 Understand the functions and disorders of the muscular system 47

Tetanus (Lockjaw) Caused from a bacterial infection of clostridium tetani usually after puncture wound. Symptoms include progressive muscle spasms, paralysis, stiffness and pain especially in jaw. Diagnosis - physical exam, lab tests, history of wound Treatment – wound hygiene, tetanus vaccine, pain management Prognosis – without treatment 1 in 4 die…with treatment less than 10% infected die 48