Chap 8 The muscular system Memmler’s A&P Chap 8 The muscular system

Functions of muscular system p161 Movement of skeleton Maintenance of posture Generation of heat

Types of muscle p160

Structure of muscle p161 p 162 Table 8-2 Endomysium Perimysium Epimysium

Neuron

Neuromuscular junction (NMJ) p162 Acetylcholine: neurotransmitter that works at the NMJ Muscle fibers have the property of excitability. The nerve impulse is an electrical current that is called an action potential.

Contraction of muscle p162 Contractility Role of calcium in muscle contraction When a muscle cell is stimulated, contraction is always the result.

Energy sources p 165 Energy sources for muscle contraction ATP Myoglobin Glycogen Creatine phosphate

Oxygen consumption p165-166 Aerobic function Anaerobic function Lactic acid Oxygen debt

Effects of exercise on muscle p166 Increase in capillaries Increase in mitochondria Increase in reserves of myoglobin, glycogen, creatine phosphate Prevent muscle atrophy and contractures

Types of muscle contractions p167 Isotonic contraction: produces movement. Ex: walking, lifting weights, running Isometric contraction: increase in muscle tension. Ex: Pushing against an immovable object Most body movements are a combination of both isotonic and isometric contractions.

Movement p167 Origin Insertion Muscles work together to accomplish skeletal movement. Prime mover Antagonist

Anterior muscles p170 Deltoid Quadriceps femoris Vastus lateralis (p178)

Posterior muscles p171 Deltoid Gluteus maximus and gluteus medius Gastrocnemius Notice the Achilles tendon Most common injury in nurses is lumbar muscle strain p175

Muscles of respiration p175

Muscular disorders 179 Spasm Strain Sprain Atrophy

Muscular diseases 179-180 Myalgia Myositis Bursitis Tendinitis Shinsplints Carpal tunnel syndrome