The Muscular system Class Notes

MUSCLES Muscles are specialized tissues that enable the body and its parts to move. There are 640 muscles in the human body. Muscles make up 40% of the bodies.

Muscle Trivia The longest muscle in the body is the sartorins which is located on the outer leg. The shortest muscle in the body is the stapedius which is located in the ear. The biggest muscle in the body is the gluteus maximus (rear end).

Muscle Functions The primary function of muscles is movement. Other functions include: 1) Maintain posture. 2) Maintain muscle tone. 3) Heat production. 4) Protect the bones and internal organs.

Muscles There are voluntary muscles and involuntary muscles. Voluntary muscles we have control over; involuntary we do not.

Muscles Muscles can be striated with lines going through them or smooth.

Types of Muscles 1) Skeletal 2) Smooth 3) Cardiac

Smooth Muscles 1) Smooth muscles are thin and spindled shaped. 2) Have no striations. 3) Involuntary muscles. 4) Contract slowly. Examples: Line blood vessels, esophagus, stomach, intestines, bladder; control digestion, breathing and urination.

Skeletal Muscles 1) Long and cylindrical. 2) Have striations. 3) Voluntary muscles. 4) Fatigue. 5) Cause movement of bones at joint.

Tendons and Joints (Skeletal) Tendons anchor muscle to the bone. Ligaments connect bone to bone.

Major Skeletal Muscles 1) Deltoids 9) Gluteals 2) Biceps 10) Hamstrings 3) Abdominals 11) Gastrocnemius 4) Quadriceps 5) Pectorals 6) Latissimus dorsi 7) Trapezius 8) Triceps

Major Skeletal Muscles 1) Deltoid: Raises your arm sideways at the shoulder. 2) Biceps: Bends your arm at the elbow 3) Abdominals: Pulls in your abdomen. Flexes your trunk so you can bend forward. 4) Quadriceps: Straightens your leg at the knee and keep it straight when you stand. 5) Pectorals: Raises your arm at the shoulder. Draws it across your chest. 6) Latissiumus dorsi: Pulls your arm down at the shoulder. Draws it behind your back.

Major Skeletal Muscles 7) Trapezius: Holds and rotates your shoulder. Moves your head back and sideways. 8) Triceps: Straightens your arm at the elbow. 9) Gluteals: Pulls your leg back at the hip. Raise it sideways at the hip. 10) Hamstrings: Bends your leg at the knee. 11) Gastrocnemius: Straightens the ankle joint so you can stand on tiptoes.

Major Skeletal Muscles

Cardiac Muscle 1) Branched 2) Striations 3) Involuntary 4) Found only in the heart 5) Pump Blood

Muscle Contraction 1) Isotonic and Concentric 2) Isotonic and Eccentric 3) Isometric

Muscle Contraction Isotonic and Concentric: - muscles shorten as they contract. - the ends of the muscle move closer together. Example: Bicep Curl

Muscle Contraction Isotonic and Eccentric: - muscles lengthen as they contract under tension. - the ends of the muscles move further apart. Example: biceps when lowering down from a pull up.

Muscle Contraction Isometric: - muscles stay the same length as they contract. Example: tug of war

Muscles Muscles always work in pairs. Muscles are made up of muscle fibers packed togther in bundles.

Types of Muscle Fibers 1) Slow Twitch 2) Fast Twitch

Fast Twitch 1) Do not have a good oxygen supply. 2) Tire very quickly. 3) Are stronger than slow twitch. 4) Contract very quickly. 5) Fast and powerful movements. 6) High intensity exercise. 7) Anaerobic activities. The more fast twitch fibers you have the more suited you are for sprinting.

Slow Twitch 1) Good oxygen supply. 2) Work for a long time. 3) Take longer to contract. 4) All types of exercise. 5) Aerobic activities.

Muscle Tone Muscle Hypertrophy – muscle increases in size. Muscle Atrophy – muscle decreases in size.