The Muscular System

1. The Muscular System Support Systems Unit 2

2. Functions of the Muscular System • Heat Production (thermogenesis) • Breaking of ATP during muscle contraction • Movement Facilitation • Muscles pull on the skeletal levers • Structure (postural support) • Muscles hold parts of the skeleton in place • Protection of Internal Organs • The abdominal muscles are thick and protect the abdominal and pelvic cavity organs

3. Types of Contractibility Voluntary- contractions controlled by conscious thought or will Involuntary- contract due to unconscious impulses sent by the autonomic nervous system or certain specialized cells or hormones

4. Muscle Appearance Striated- stripes, muscles that on a microscopic level have cross fiber stripes Non-striated- Not having stripes, muscles cells that microscopically have a smooth appearance

5. Cardiac Muscle • Forms the bulk of heart wall (Myocardium) • Striated • Involuntary (typically) • Cardiac fibers typically have a centrally located nucleus • Intercalated discs • Strengthens cardiac muscle tissue • Allows for special wringing muscle contraction

6. Cardiac Muscle Tissue

7. Smooth Muscle • Located in walls of hollow internal surfaces such as: • blood vessels - stomach • urinary bladder - intestines • Non-striated in appearance • Involuntary (typically) • Contractions usually move things along, from point A to point B (peristalsis)

8. Smooth Muscle Tissue

9. Skeletal Muscle • Attached to bones • Striated appearance under a microscope • Voluntary control (conscious control) • Allow for postural support and movement of body parts, both axial and appendicular

10. Skeletal Muscle Tissue

12. Connecting Tissues Tendon–muscle to bone Ligament- bone to bone

13. Motions Peristalsis- a wave like motion by smooth muscle to advance substances Abduction- movement away from midline Adduction- movement towards midline Flexion- decreasing a joint angle Extension- increasing a joint angle Hyperextension- extension past normal extension, or past anatomical position

14. Motions Plantarflexion- specific to ankle motion, pointing the toes Dorsiflexion- specific to ankle motion, pulling the toes towards the shin Supination- turning palm up Pronation- turning palm down Rotation- movement around an axis

15. Biceps brachii- anterior surface of arm between the shoulder and elbow, flexes the elbow Triceps brachii- posterior aspect of arm between the shoulder and elbow, extends the elbow Trapezius- attaches to the spine from the occiput through the thoracic region and to the spine of the scapula, extends or hyperextends the head and neck, (also helps with shoulder retraction and elevation and depression) Deltoid- covers the cap of the shoulder, abducts the arm Diaphragm- connects to the lower ribs and runs through the entire body, deflects the diaphragm inferiorly increasing volume of the thoracic cavity Location and Function of Skeletal Muscles

16. Location and Function of Skeletal Muscles Pectoralis major- attaches to the upper ribs along the sternum and to the humerus, adducts the arm Latissimus dorsi- attaches along mid to lower spine and pelvic and to the humerus, extends a flexed arm or hyperextends the arm from the anatomical position Rectus abdominus- attaches to the lower ribs and to the pelvic anteriorly, flexes the lumbar spine Gastrocnemius-attaches to the tibia and lower femur and uses the achilles tendon to attach to the calcaneous (heel bone), plantar flexes the ankle when the knee is in extension

17. Soleus- attached deep to the gastrocnemius on the tibia and uses the achilles tendon to attach to the calcaneous, plantarflexes the ankle when the knee is bent Hamstrings- posterior thigh between the hip and knee, flexes the knee Quadriceps- anterior thigh between the hip and knee, extends the knee Gluteus maximus- posterior pelvis, extends a flexed thigh or hyperextends the thigh from the anatomical position Location and Function of Skeletal Muscles

18. Anterior Skeletal Muscles

19. Posterior Skeletal Muscles

20. Diseases and Disorders of the Muscular System

21. Tendonitis • Tendonitis is characterized by Inflammation of the tendons due to overuse or age-related changes of the tendon. • It is common in individuals who begin a new exercise or increase their level of exercise. • Age-related tendonitis is due to the loss of elasticity and the ability of the tendon to glide smoothly. • Treatment includes: rest, ice, compression, and elevation (RICE).

22. Sprain • A sprain is an injury to a ligament, which is the fibrous tissue that connects bones to other bones. • There are three grades of sprains: • 1st Degree Sprain = stretching of ligaments • 2nd Degree Sprain = partial tearing of ligaments • 3rd Degree Sprain = complete tear of ligaments

23. Three Degrees of Sprains

24. Strains • Muscle strain or muscle pull or even a muscle tear implies damage to a muscle or its attaching tendons. • This can occur due to excessive pressure on muscles during the course of normal daily activities, with sudden, quick heavy lifting, during sports, or while performing work tasks.

25. Degrees of Muscle Strains First degree strain - a mild strain when only a few muscle fibers are stretched or torn. The injured muscle is tender and painful, but has normal strength. Second degree strain - a moderate strain with a greater number of injured fibers. There is more severe muscle pain and tenderness. There is also mild swelling, some loss of strength, and a bruise may develop. Third degree strain - this strain tears the muscle all the way through. There is a total loss of muscle function.

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31. Vocabulary- word parts • My/o- muscle (myofibril is a muscle fiber) • Ab- prefix, away (abduction) • Ad- prefix, towards (adduction) • Bi- prefix, two (biceps) • Tri- prefix, three (triceps) • Quad- prefix, four (quadriceps) • Contra- prefix, opposite or against (contralateral- pertaining to the other side) • Dys- prefix, bad, difficult, or painful (dysphagia- difficulty swallowing) • -algia- suffix, pain (myalgia- muscle pain)

32. Vocabulary Ligament- connective tissue that holds bone to bone Tendon- connective tissue that hold muscle to bone Tendonitis- inflammation of a tendon Sprain- stretch or tear of a ligament Strain- stretch or tear of a muscle or tendon Myocardium- heart muscle Thermogenesis- heat production Striations- stripes MRI- Magnetic Resonance imaging