The Muscular System

1. The Muscular System

2. Muscle System Functions • Provides voluntary movement of body • Enables breathing, blinking, and smiling • Allows you to hop, skip, jump, or do push-ups • Maintains posture • Produces heat

3. Functions Continued • Causes heart beat • Directs circulation of blood • Regulates blood pressure • Sends blood to different areas of the body

4. Functions Continued • Provides movement of internal organs • Moves food through digestive tract • Enables bladder control • Causes involuntary actions • Reflex actions • Adjusts opening of pupils • Causes hair to stand on end ( )

5. Is made up of contractile fibers Provides movement Controlled by the nervous system Voluntary- consciously controlled Involuntary- not under conscious control Examples Skeletal Smooth Cardiac Muscle Tissue Characteristics Skeletal Smooth Cardiac

6. Types of Muscle Tissue • There are three main types of muscle tissue • Skeletal(striated) • Cardiac(heart) • Smooth(visceral)

7. Long + slender Branching Spindle shape Comparison of Muscle Types Muscle Type Skeletal Cardiac Smooth Attached to bone Walls of internal organs + in skin Heart Location Movement of bone Movement of internal organs Beating of heart Function Control Mode Voluntary Involuntary Involuntary Shape Striated- light and dark bandsMany nuclei StriatedOne or two nuclei Non-striatedOne nucleus(visceral) Characteristics

8. External Obliques Deltoid Masseter Rectus abdominis Quadriceps Group biceps brachii Quadriceps group Pectoralis Major Brachioradialis Frontalis Tibialis Anterior Location of Muscles • SkeletalMuscles • Anterior view

9. Trapezius Latissimus dorsi Gluteus maximus Triceps brachii Gastrocnemius Hamstring group Hamstring group Locationof Muscles • SkeletalMuscles • Posteriorview

10. Location of Muscles • InvoluntaryMuscles • Diaphragm • Digestive organs • Arrector pili • Heart • Urinary bladder • Muscles aroundblood vessels

11. bundle of muscle fibers – fascicle Muscle Tissue Anatomy

12. Muscle TIssue • Muscles are made up of bundlesof muscle fibers, called fascicles • Fascicle is a bundle of muscle fibers • A muscle fiber is a muscle cell….made up of many small myofibrils • Myofibrils contain filaments • Two types ofprotein filaments Anatomy Muscle Fascicle Muscle Fibers Myofibrils Filaments

13. Sarcomere Myofibril Thin Filaments • Contain two types of protein filaments • Actin- thinproteinfilaments • Myosin- thickprotein filaments • Z disc- point of anchor of actin • Sarcomere- functional unit of a myofibril, region between Z discs, ActinMolecule Sarcomere Z Disc Thick Filaments Myosin Molecule

14. A motor unit Mechanics of a Muscle Contraction • What stimulates a muscle to contract? • Your nervous system • What cells are involved? • Muscle cells and a motor neuron • Motor neuron sends impulse to muscle cells • One neuron will form synapses with many muscle cells • What is this called? • A motor unit • Let’s take a look under the microscope.…

15. Neurotransmitters Mechanics of a Muscle Contraction • Where does stimulation occur? • Neuromuscular junction • How do motor neurons communicate with muscle cells? • Neurotransmitters (typicallyacetylcholine) carryimpulse signal across the gap • What happens when a muscle cell is stimulated? • Calcium ions are released into the muscle cell

16. Mechanics of a Muscle Contraction • What do calcium ions do? • Cause interaction between actin and myosin • How do actin and myosin interact? • Actin filaments slide over the myosin filaments. • What model explains this? • Sliding Filament Model

17. Mechanics of a Muscle Contraction • What provides the energy to swivel the head of myosin? _____ • How exactly does the sliding filament model work? • In the sliding filament model of muscle contraction, the (thin) actin filaments[red] (that are attachedto the Z-line) slide (areactually pulled) inward along the (thick)myosin filaments [blue], and the sarcomere (measuredfrom one Z line to thenext) is shortened. ATP

18. How long does a muscle cell remain contracted? Until the release of acetylcholinestops. How strongly does a muscle fiber contract? To it’s fullest extent. All-or-none response So what controls the strength of a contraction? Number of muscle cells recruited To get a stronger contraction, more cells are stimulated A single cell can’t contract harder Control of a Muscle Contraction

19. MuscleFiber Deltoid muscle Myofibril Actin sarcomere Myosin A Closer Look at Muscle Contraction

20. Belly ofBiceps Macroscopic Structure of Muscle Tendon • _________- attaches muscle to bone • _______- attachment of muscle to immovable (fixed) bone (anchors muscle) • ________- attachment to bone that moves when muscle contracts • _____- bulging middle part of the muscle Origin Insertion Belly

21. Muscles originate on a _____bone in our body, cross over a ______, and insert onto a ______ bone. It is important to understand that all muscles move from the ________ point going toward the __________ point. It is because of the placement of the muscles that we can move. Muscle Movement fixed moving joint insertion origination

22. Muscle Movement • Tendons • attach _________ to bone • are inelastic • don’t stretch when the force of the muscle acts on them • When muscle contracts, it pulls on the _______ • Individual muscles can only ____ in ____ direction • Muscles work in opposing ______ muscle bone pull one pairs

23. Muscle Movement Flexor • ______- Muscle that bends the joint when contracted. • ________- Muscle that straightens the joint when contracted. • __________ muscleis short, firm, tight and thicker around. • _______ muscle is stretched, long, loose and thinner around. Extensor Contracted Relaxed

24. When the biceps in the arm contracts the triceps ________ causing ________ of the arm. When the triceps in the arm _________ the bicepsrelaxes causing ____________ of the arm. ______ of muscles are needed because the only active _________ of a muscle is to _______- to lengthen it must be _________ by the action of an opposing _______. Muscle Movement bending relaxes contracts straightening Pairs movement contract stretched muscle

25. Categories of skeletal muscle actions • CategoriesActions • Extensor Increases the angle at a joint • Flexor Decreases the angle at a joint • Abductor Moves limb away from midline of body • Adductor Moves limb toward midline of body • Levator Moves insertion upward • Depressor Moves insertion downward • Rotator Rotates a bone along its axis • Sphincter Constricts an opening

27. Naming Skeletal Muscles • Location of the muscle • Shape of the muscle • Relative Size of the muscle • Direction/Orientation of the muscle fibers/cells • Number of Origins/attachments • Location of the Attachments • Action of the muscle

28. Muscles In Action HYPERMUSCLE: MUSCLES IN ACTION • Click above to get to this multimedia interactive HTML document which will help you learn the muscle actions of the human body.

29. A is a wrenching, twisting or stretching injury to a ligament. Sprains often affect theankles, knees, or wrists. Muscle Disorders Sprain Result in pain, swelling, redness, bruising, and difficulty using injured joint.

30. A strain is an injury to a muscle or tendon, and is often caused by overuse, force, or stretching. Injured area experiences: pain and soreness swelling warmth, bruising, or redness difficulty using or moving the injured area in a normal manner Muscle Disorders Strain

31. Muscle Disorders Muscle Ruptures • There are three degrees of muscle ruptures • A muscle tear may be partial or complete and caused either by a direct blow or by overexertion. • A first-degree strain involves less than 5 percent of the muscle. • mild pain and not much loss of strength or range of motion. • Mild tears referred to as pulled muscles. • A second-degree tear is a greater rupture that stops short of a complete tear. • Any contraction of the torn muscle will cause pain. • There may be a defect of the muscle - a bump or an indentation - at the site of the most pain. • You should be able to partially contract the muscle, but not without pain • A third-degree rupture is a complete tear across the width of the muscle • You will be unable to contract the muscle. • This is what happens when someone suddenly drops while sprinting. • The torn end of the muscle may ball up and form a large lump under the skin, and a great deal of internal bleeding occurs. • Severely torn muscles may require surgery to heal properly.

32. Muscle Tears Muscle Disorders Muscle Pull Muscle Tear • Muscle pull- very slight tear • Chronic tear- gradual onset of pain • Acute tear- sudden dramatic pain

33. Muscle Disorders Shin splints • Shin splints is pain resulting from damage to the muscles along the shin. Pain is felt in different areas, depending on which muscles are affected. Shin splints represent an "overuse injury" and occur most commonly in runners.

34. Muscle Disorders Treatment for Muscle Injuries • R.I.C.E. • Rest: Stop all activities whichcause pain. • Ice: Helps reduce swelling. Never ice more than 10-15 min. at a time. Protect the skin. • Compression: Wrap the strained area to reduce swelling. • Elevation: Keep the strained area as close to the level of the heart as is conveniently possible to keep blood from pooling in the injured area.

35. Muscle spasm- when A muscle (or even a few fibers of a muscle) involuntarily contract Muscle cramp- involuntarily + forcibly contracted muscle that does not relax A forceful + sustained spasm Nick named charley horse Muscle feels tied up in knots Muscle Disorders Spasms Cramps • Can last anywhere from a few seconds to a quarter of an hour • Caused by strain or injury

36. Tetanus is a preventable disease through vaccination Caused by bacteria that enters the body through the skin Found in soil, dust and manure Toxin bacteria produces interferes with nerve transmission to your muscles and causes them to seize up in painful spasms. Tetanus typically starts in the jaw and muscles of the face, quickly spreading to the arms and legs. “Lockjaw” Difficulty swallowing Intestines often seize up Bladder fails to empty Asphyxiation Cardiac arrest Muscle Disorders Tetanus

37. Produced naturally by the body to support such functions as fighting stress and promoting growth and development People use steroid pills, gels, creams, or injections to improve their sports performance or the way they look. Anabolic steroids cause many different types of problems Side effects/problems premature balding or hair loss dizziness mood swings problems sleeping nausea and vomiting high blood pressure aching joints urinary problems shortening of final adult height increased risk of heart disease,stroke, and some cancers Muscle Disorders Anabolic Steroids