Muscular System PDF

 Identify the three Label and Identify what is main parts of describe the muscular system. muscular system. functions of the main muscles.  The muscular system is an organ system...

 Identify the three Label and Identify what is main parts of describe the muscular system. muscular system. functions of the main muscles.  The muscular system is an organ system in the body. It consists of skeletal, smooth and cardiac muscle. Its role is to help the body to move, maintain posture and circulate blood through the body.  1. Movement 2. Maintenance of posture and muscle tone 3. Heat production 4. Protects the bones and internal organs.  muscles move bones by pulling, not pushing. ⚬ Synergists – any movement is generally accomplished by more than one muscle. All of the muscles responsible for the movement are synergists. the one that is most responsible for the movement is the PRIME MOVER (agonist).  Antagonists–muscles and muscle groups usually work in pairs ⚬ example the biceps flex your arm and ts part ner the triceps extend your arm. The two muscles are antagonists, i.e. cause opposite actions. ⚬ when one contracts the other relaxes. Levators– muscle that raise a body part. We are able to maintain our body position because of tonic contractions in our skeletal muscles. These contractions don’t produce movement yet hold our muscles in position. contraction of muscles produces most of the heat required to maintain body temperature.  Involuntary muscles are muscles 1. Smooth muscle –an involuntary which are not under our conscious muscle found in the internal control. organs and blood vessels 2. Cardiac muscle – an involuntary Voluntary muscles are muscles which muscle found only in the heart are under our conscious control, so we 3.Skeletal muscle – a voluntary can move these muscles when we muscle attached to the skeleton choose to.  Fibers are thin and spindle shaped. No striations Single nuclei Involuntary Contracts slowly They fatigue… but very slowly 1. Found in the circulatory system 3.Found in the respiratory system Lining of the blood vessels Controls breathing Helps in the circulation of the blood 4.Found in the urinary system 2.Found in the digestive system Urinary bladder Esophagus, stomach, intestine Controls urination Controls digestion Cells are branched and appear fused with one another Has striations Each cell has a central nuclei Involuntary  Found ONLY in the heart Contractions of the heart muscles pump blood throughout the body and account for the heartbeat. Healthy cardiac muscle NEVER fatigues  Fibers are long and cylindrical Has many nuclei Has striations ⚬ have alternating dark and light bands Voluntary  Attached to skeleton by tendons Causes movement of bones at the joints. And yes… they do fatigue  Bursae– small fluid filled sacs that lie between some tendons and the bones beneath them. They are made of connective tissue and are lined with synovial membrane that secretes synovial fluid.  The membrane that surrounds the muscle cell is called the sarcolemma. Muscle cells are filled with 2 types of fine thread like proteins: MYLOFILAMENTS lmyosin(thick) lactin(thin).  TYPE 1 TYPE II Type IIa (oxidative) - pink muscle which are red muscle which produces a small produces a medium amount of force, amount of force, contracts slowly and contracts quickly and has a medium resistance to fatigue resists fatigue well Type IIx (glycolitic) - white muscle which produces a large amount of force, contracts very quickly but fatigues quickly The deltoid is responsible for the abduction of the shoulder (moving the arm out and away from the body). The pectoralis major is responsible for the adduction of the shoulder (moving the arm towards the body) and the shoulder horizontal flexion (moving the arm forwards in front of the body).  Biceps are responsible for flexing the elbow (bending the arm).  The external obliques are responsible for trunk rotation (twisting the body).  The hip flexors are responsible for hip flexion (moving the knee up to the chest). The quadriceps are responsible for extending the knee (straightening it).  The tibialis anterior is responsible for dorsiflexion of the ankle (bringing the toes up in the direction of the shin). Triceps are responsible for extending the elbow (straightening it).  The Latissimus dorsi are responsible for shoulder adduction (moving the arm towards the body).  The gluteus maximus is responsible for hip extension (moving the leg backwards).  The hamstrings are responsible for flexing the knee (bending the leg).  The gastrocnemius is responsible for plantar flexion of the ankle (pointing the toes downwards).  Isotonic contractions- this includes concentric contraction, where the muscle shortens and fattens, as well as eccentric contraction where the muscle lengthens and flattens. Isometric contraction – this involves a muscle staying the same length despite building tension. This occurs when the body remains in one position.  Antagonistic pairs are pairs of muscles which work together by one contracting (shortening) and one relaxing (lengthening). The contracting muscle is an agonist and the relaxing muscle is an antagonist. 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 upward ROTATOR Rotates a bone along its axis SPHINCTER Constrict an opening 1.Size: vastus (huge); maximus (large); longus (long); minimus (small); brevis (short). 2.Shape: deltoid (triangular); rhomboid (like a rhombus with equal and parallel sides); latissimus (wide); teres (round); trapezius (like a trapezoid, a four-sided figure with two sides parallel).  3. Direction of fibers: rectus (straight); transverse (across); oblique (diagonally); orbicularis (circular). 4. 4.Location: pectoralis (chest); gluteus (buttock or rump); brachii (arm); supra- (above); infra- (below); sub- (under or beneath); lateralis (lateral). 5.Number of origins: biceps (two heads); triceps (three heads); quadriceps (four heads).  6.Origin and insertion: sternocleidomastoideus (origin on the sternum and clavicle, insertion on the mastoid process); brachioradialis (origin on the brachium or arm, insertion on the radius). 7. Action: a. abductor (to abduct a structure); b. adductor (to adduct a structure); c. flexor (to flex a structure); d. extensor (to extend a structure); e. elevator (to lift or elevate a structure); f. masseter (a chewer). ,