Presentation on theme: "The Muscular System Video to Introduce Skeletal & Muscular System"— Presentation transcript:
1The Muscular System Video to Introduce Skeletal & Muscular System
2Interesting Facts You have about 650 muscles in your body. Your muscles make up half of your body weightMuscle cells cannot partially contract. They act on the ‘all or none’ principle. They either contract 100% or do not contract at all.
3You cannot turn fat into muscle by exercising. You cannot ‘spot reduce’. In other words, a person cannot get rid of his/her spare tire by doing sit-ups.When you are cold, your muscles produce rapid contractions to generate body heat (shivering).A cramp is a painful muscle contraction.
4Tetanus is a very severe type of contraction Tetanus is a very severe type of contraction. It is a persistent contraction that can be caused by a bacterial infection. Sometimes you get a ‘tetanus shot’ to prevent this. Tetanus can cause lockjaw.A spasm is rapid involuntary contraction of a muscle. You may have had one in your eye before - tick.
5It takes more muscles to Did you know……..?It takes more muscles tofrownthan tosmile?
6Muscles are important because they… Hold the organs in placeHold the bones together to allow movementGenerate heatPump your bloodAllows you to breatheMaintain postureStabilize joints
8MovementYou are always moving. Even when you are sleeping, your muscles are working. Movement only stops when life stops.Movement within cells is caused by chemical reactions. All other body movements are caused by muscles.
9You have more than 650 muscles. Muscles make up 40% of your body mass.Muscles work by contracting. When a muscle contracts it shortens. Without your muscles, your bones could not move. When a muscle contracts it pulls on a bone, producing movement. Muscles can only pull bone; they cannot push bones.
12Types of MusclesNot all our muscles are used for locomotion. Some allow us to wink, swallow etc. There are three main types of muscles. At the cellular level they all have the same function – to contract. When we move beyond the cellular level we see differences in their functions:
14Type 1: Skeletal Muscle Muscles that move your arms and legs These are the ones that you control – they move when you want them toThey are attached to boneOften called voluntary musclesUnder a microscope they look striped or striated so they are called striated muscles. These are “stringy” muscles (like chicken breasts)
16Type 2: Smooth MuscleOften called involuntary muscles because you cannot control themThese muscles form the wall of most of the digestive tract; they are also found in blood vessels and other internal organsUnder a microscope they look smooth
18Type 3: Cardiac Muscle This is the heart muscle Under a microscope, cardiac muscle appears striated like voluntary muscles BUT cardiac muscle is involuntary – you have no control over your cardiac muscle
20Muscle AttachmentFor one bone to move toward another bone, a muscle is needed. This muscle will have 2 points of attachmentOrigin: The place at which a muscle is attached to the stationary (not moving) boneInsertion: The place at which a muscle is attached to the movable bone
22What are tendons? Most muscles are attached by tendons to bones Tendons are tough, inelastic bands of connective tissue – they are very strongA tendon is the thickness of a pencil and can support a load of several thousand kilos
25As the tendons are small, they can pass in groups over a joint or attach to very small areas for the muscle itself to find room for attachmentAlthough they are very tough, they are subject to wear and tear as they rub across bone surface
27Tendons may become inflamed (tendonitis) when athletes work out in cold weather without adequate warm clothing, or without doing warm ups
28Antagonistic Muscle Pairs Many muscles act in pairsThis is necessary since a muscle can only pull by contractingWhen a bone moves, movement in the opposite direct can occur only if there is another muscle that can pull the bone in that directionThese muscles are called antagonistic pairs
30Exercise Type 1: Isotonic Exercise There are two types of exercise: Results in movementEx) running, lifting weights etc
31Type 2: Isometric Exercise Muscles are pitted against each otherThis is exercise that does NOT result in movementEx) Pushing a wall; hooking fingers together and trying to pull hands apartSuch exercises have been shown to increase strength and muscle size rapidly
32Movement in JointsAbduction: movement away from the side of the trunk or midline of the body (ex. raising arms to the side; swinging leg to the side)Adduction: movement toward the trunk or midline (opposite of abduction)
40Horizontal adduction: movement of humerus from side-horizontal to front-horizontal (ex. pushing a barbell during a bench press)Horizontal abduction: movement of humerus from front-horizontal to side-horizontal (ex. rowing a boat)
52Sternocleidomastoid muscle is a paired muscle in thesuperficial layers of theanterior portion of the neck.It acts to flex and rotate the head.It originates at the sternum andclavicle; and inserts in the mastoidprocess.
53Trapezius muscle the trapezius is a large superficial muscle that extendslongitudinally from the occipitalbone to the lower thoracic vertebraeand laterally to the spine of thescapula (shoulder blade).Its functions are to move thescapulae and support the arm.The trapezius has three functionalregions: the superior region(descending part), which supportsthe weight of the arm; the intermediateregion (transverse part), which retractsthe scapulae; and the inferior region(ascending part), which medially rotatesand depresses the scapulae.
54Rhomboid muscle often simply called the rhomboids, are rhombus-shaped musclesassociated with the scapula andare chiefly responsible for its retraction.
55Deltoid muscle The deltoid muscle is the muscle forming the rounded Back viewThe deltoid muscle is themuscle forming the roundedcontour of the shoulder. Thedeltoid is the prime mover ofarm abduction along the frontalplane. The deltoid muscle alsohelps the pectoralis major inshoulder flexion and the latissimusdorsi in shoulder extension.Front viewSide view
56Latissimus dorsi muscle is the larger, flat, dorso-lateral muscleon the trunk, posterior to the arm, andpartly covered by the trapezius on itsmedian dorsal region. It adducts,extends and internally rotates the arm.
57Pectoralis major muscle is a thick, fan-shaped muscle,situated at the chest (anterior)of the body. It makes up the bulkof the chest muscles in the maleand lies under the breast in the female.Actions: flexes the humerus, extendsthe humerus. As a whole, adducts andmedially rotates the humerus.
58Biceps brachii muscle is a muscle located on the upper arm. The term biceps brachii is a Latin phrasemeaning "two-headed [muscle] of the arm",The biceps has several functions,the most important being to rotatethe forearm (supination) and toflex the elbow.
59Brachioradialis is a muscle of the forearm that acts to flex the forearm at theelbow. It is also capable of bothpronation and supination, dependingon the position of the forearm.
60Brachialis The brachialis is the Strongest flexor of the elbow. Unlike the biceps,the brachialis does notinsert on the radius, andtherefore cannot participatein pronation and supinationof the forearm.
61Triceps brachii muscle The triceps brachii muscle(Latin for "three-headed arm muscle")is the large muscle on the back of theupper limb of many vertebrates. It isthe muscle principally responsiblefor extension of the elbow joint(straightening of the arm).
62Rectus abdominis muscle is a paired muscle running verticallyon each side of the anterior wall ofthe human abdomen. There are twoparallel muscles, separated by a midlineband of connective tissue called thelinea alba (white line). The rectus isusually crossed by three fibrous bands.The rectus abdominis is an importantpostural muscle. It is responsible forflexing the lumbar spine, as whendoing a "crunch".
63Gluteus maximus muscle The gluteus maximus is the largestand most superficial of the threegluteal muscles. It makes up a largeportion of the shape and appearanceof the buttocks. Its large size is one ofthe most characteristic features of themuscular system in humans, connectedas it is with the power of maintaining thetrunk in the erect posture. The gluteusmaximus extends the femur and brings thebent thigh into a line with the body.
64Gluteus Medius and Gluteus Minimus With the leg in neutral (straightened),the gluteus medius and gluteus minimusfunction together to pull the thigh awayfrom midline, or "abduct" the thigh. Helpsbalance the body on one leg when walking.
65Hamstring the hamstring refers to posterior thigh muscles, the semitendinosus, thesemimembranosus and thebiceps femoris. The hamstrings crossand act upon two joints –the hip and the knee.Semitendinosus and semimembranosusextend the hip when the trunk is fixed;they also flex the knee and medially(inwardly) rotate the lower leg whenthe knee is bent.The long head of the biceps femorisextends the hip as when beginning towalk; both short and long heads flexthe knee and laterally (outwardly)rotates the lower leg when the knee is bent.The hamstrings play a crucial role inmany daily activities, such as, walking,running, jumping, and controlling somemovement in the trunk. In walking,they are most important as anantagonist to the quadriceps in thedeceleration of knee extension.
66Quadriceps is a large muscle group that includes the four prevailing muscles on the frontof the thigh. It is the great extensor muscleof the knee, forming a large fleshy masswhich covers the front and sides ofthe femur. It is the strongest and leanestmuscle in the human body. It is made upthe vastus intermedius, vastus lateralis,vastus medialis, and rectus fermoris.All four quadriceps are powerfulextensors of the knee joint. Theyare crucial in walking, running,jumping and squatting. Becauserectus femoris attaches to the ilium, it isalso a flexor of the hip.
67Sartorius muscle The Sartorius muscle – the longest muscle in the human body – is a longthin muscle that runs down the lengthof the thigh. Assists in flexion, abductionand lateral rotation of hip, and extensionof knee. Looking at the bottom of one'sfoot, as if checking to see if one hadstepped in gum, demonstrates all fouractions of sartorius.
68Tibialis anterior is a muscle that originates in the upper two-thirds of the lateral surfaceof the tibia and inserts into the medialcuneiform and first metatarsal bonesof the foot. Its acts to dorsiflex andinvert the foot.
69Gastrocnemius is a very powerful superficial pennate muscle that is in the back part of thelower leg. It runs from its two headsjust above the knee to the heel, andis involved in standing, walking, runningand jumping. Along with the soleusmuscle it forms the calf muscle. Itsfunction is plantar flexing the foot atthe ankle joint and flexing the leg atthe knee joint.
70Soleus is a powerful muscle in the back part of the lower leg (the calf). Itruns from just below the knee tothe heel, and is involved in standingand walking. The action of thecalf muscles, including the soleus,is plantarflexion of the foot.
71Muscle Labeling Assignment Label the following muscles on the handout provided in class:TrapeziusDeltoidTricepsBicepsPectoralis majorQuadricepsGastrocnemiusBrachioradialisGluteus maximusHamstring musclesSteroncleidomastoidRectus abdominis