Presentation on theme: "The Muscular System Unit 3 Objectives:"— Presentation transcript:
1 The Muscular System Unit 3 Objectives: Be able to explain the differences between the 3 types of muscles in the human bodyBe able to describe common muscle actions and how muscle contractions are initiatedBe able to name the major skeletal muscles of the body (human and cat) as well as their origin/insertion points
2 Identify the 8 muscles above. Group 1 Muscles85567678Warm- Up 10/6/11:Identify the 8 muscles above.
3 The Muscular SystemMuscles are responsible for all types of body movementMuscle Functions:MovementMaintain postureStabilize jointsHeatThree basic muscle types found in the body:Smooth muscleCardiac muscleSkeletal muscle
4 Characteristics of Muscles Muscle cells are elongatedContraction of muscles is due to the movement of microfilaments – many cells contracting at the same timeAll muscles share some terminologyPrefix myo refers to muscle
5 Smooth Muscle Characteristics: How blood and food move No striationsSpindle-shaped cellsSingle nucleusInvoluntary – no conscious controlFound mainly in the walls of hollow organs (blood vessels, intestines)Figure 6.2a
6 Cardiac Muscle Characteristics: What makes your heart beat? StriationsUsually only one nucleusCells joined to each other at an intercalated discInvoluntaryFound only in the heartFigure 6.2b
7 Skeletal Muscle Characteristics: Moving your bones! Most are attached by tendons to bonesRemember “tendons tug”Cells have more than one nucleusStriated – have visible bandingVoluntary – subject to conscious controlCells are surrounded and bundled by connective tissue
8 Connective Tissue Wrappings of Skeletal Muscle Endomysium – around single muscle fiberPerimysium – around a bundle of fibersEpimysium – covers the entire skeletal muscleFascia – on the outside of the epimysiumFigure 6.1
10 Skeletal Muscle Attachments Epimysium blends into a connective tissue attachment; the tendon – a cord-like structureSites of muscle attachmentBonesCartilagesConnective tissue coveringsAnimation:
11 Contraction of a Skeletal Muscle VideoMuscle fiber contraction is “all or none”Within a skeletal muscle, not all fibers may be stimulated during the same intervalDifferent combinations of muscle fiber contractions may give differing responsesGraded responses – different degrees of skeletal muscle shorteningMust have ATP in order to contract
12 Muscle Response to Strong Stimuli Muscle force depends upon the number of fibers stimulatedMore fibers contracting results in greater muscle tensionMuscles can continue to contract unless they run out of energy (ATP)
13 Energy for Muscle Contraction Initially, muscles used stored ATP for energy – aerobic activitiesBonds of ATP are broken to release energyOnly 4-6 seconds worth of ATP is stored by musclesAfter this initial time, other pathways must be utilized to produce ATP – anaerobic activities and lactic acid build-up
14 Muscle Fatigue and Oxygen Debt When a muscle is fatigued, it is unable to contractThe common reason for muscle fatigue is oxygen debtOxygen must be returned to tissue to remove oxygen debtOxygen is required to get rid of accumulated lactic acidIncreasing acidity (from lactic acid) and lack of ATP causes the muscle to contract less
15 Muscles and Body Movements Movement is attained due to a muscle moving an attached boneMuscles are attached to at least two pointsOrigin – attachment to an immoveable boneInsertion – attachment to a movable boneFigure 6.12
16 Ordinary Body Movements Flexion – decreases the angle between two adjacent body segmentsExtension – increases the angle between two adjacent body segmentsRotation – the bone distal to the joint is moved either toward (medial) or away from (lateral) the midlineAbduction – movement of a body part away from the midlineAdduction – movement of a body part back toward the midlineCircumduction – a combination of flexion, abduction, extension, and adduction
20 Naming of Skeletal Muscles Direction of muscle fibersExample: rectus (straight)Relative size of the muscleExample: maximus (largest)Location of the muscleExample: many muscles are named for bones (e.g., temporalis)Number of originsExample: triceps (three heads)
21 Naming of Skeletal Muscles Location of the muscle’s origin and insertionExample: sterno (on the sternum)Shape of the muscleExample: deltoid (triangular)Action of the muscleExample: flexor and extensor (flexes or extends a bone)
29 Movement Worksheet p.1Standing on your toes as in ballet is (1) of the foot. Walking on your heels is (2) . Winding up for a pitch (as in baseball) can properly be called (3) . To keep your seat when riding a horse, the tendency is to (4) your thighs. In running, the action at the hip joint is (5) in reference to the leg moving forward and (6) in reference to the leg in the posterior position. When kicking a football, the action at the knee is (7) . In climbing stairs, the hip and knee of the forward leg are both (8) .
30 You have just touched your chin to your chest; this is (9) of the neck You have just touched your chin to your chest; this is (9) of the neck. Using a screwdriver with a straight arm requires (10) of the arm. Consider all the movements of which the arm is capable. One often used for strengthening the upper arm and shoulder muscles is (11) . Moving the head to signify “no” is (12) . Action that moves the distal end of the radius across the ulna is (13) . Raising the arms laterally away from the body is called (14) of the arms.When you are cupping your hands in order to hold a bowl of soup, the position is called __(15)__.
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