Muscular system notes

Warm up:How many muscles do we have?

• over 600

Facts about your muscular system:

• there are muscles in the root of your hair that give you goosebumps (arrector pilli)

• it takes 17 muscles to smile and 42 muscles to frown

• the hardest working muscle is the heart

• the largest muscle in our body is the gluteus Maximus and the smallest muscles are in the inner ear and are the tensor tympani and stapedius

Muscular system:

• contains over 600 muscles

• 40% of body weight

Functions:

• movement

• supports posture

• produces heat and energy

• protects internal organs

• moves blood, food, and waste products through the body

• opens and closes body openings

Muscle traits:

• 5 common traits:

  • excitability or irritability: the ability to respond to stimuli, such as a nerve or hormone

  • intractability: the ability to shorten/move when stimulated

  • extensibility: the ability to be stretched and lengthen

  • elasticity: the ability to return to original shape after contracting

  • muscle tone: contracted at all times and readiness to act

Warm up: what does each muscle have?

• its own nerve, vein, and artery

• Cardiac: muscle forms the walls of the heart

visceral or smooth muscle, are found in hollow organs, walls of blood vessels and eyes

• skeletal muscles is attached to the bone

Warm up: name the 5 functions of the muscular sysem

• movement, generates heat, supports posture, protects internal organs, stabilizes joints, moves blood, food, and waste

Voluntary and involuntary muscle

• cardiac and visceral muscles are involuntary, which means that they are not controlled by a person’s conscious thought

• most skeletal muscles are voluntary, which means they are controlled

Types of Muscle

Shapes of muscle

• triangular- shoulder, neck

• spindle- arms, legs

• flat- diaphragm, forehead

• circular - mouth, anus

Attachment of skeletal muscles

• while ligaments attach bone to bone, muscles are attached to bones by bands of fibrous tissue called tendons

• fascia is a sheet of tough fibrous tissue that wraps around an individual muscle fiber

• the end of muscle that is connected to the bone that does not move is called the origin

• the end connected to the bone that moves when muscle contracts is called the insertion

  • ex: biceps brachii:

    • origin- scapula

    • insertion- radius

Warm up 3/20: what are the 4 shapes of muscle and give example

triangular: shoulder

spindle: arms, legs

flat: forehead

circular: mouth

Types of body movements

• types of body movements made by skeletal muscles include:

  • flextion : bending a body part, which decreases the angle of the joining

  • extension: straightening a body part, which increases the angle of the joint

  • abduction: moving a body part away from the midline

  • adduction: moving a body part toward the midline

  • circumduction: turning body part in a circular motion

  • pronation: turning downwards or posteriorly

  • supination: turning upwards or forward

Sarcomers- basic unit of striated muscle tissue

• structure- muscle fibers are made of units called myofibrils

  • 2 protein fibers

• thick filaments: are made of bonded units of proteins. myosin is the thick filament protein that enables muscles to contract

• thin filaments. 3 proteins

  • actin makes up the bulk of thin filament mass

  • contains myosin-binding sites that allow it to move actin during muscle contraction (sliding filament theory)

  • tropomyosin- long protein fiber that wraps around actin and covers myosin binding sites

  • troponin- moves tropomyosin away from myosin binding sites

Exercise and muscles

• isotonic- muscles contract and movement occurs (bench press, curls, etc)

• isometric- tension in muscles increases, no movement occurs (planks, wall sits etc)

Warm up 3/21: what are the proteins that make up the thin and thick filaments and what do they allow muscles to do?

muscles always pull

Muscles:

sternocleidomastoideus: flexes and rotates head

masseter: elevate jaw, origin: zygomatic arch, insertion: mandible

temporalis and orbicularis oris: orbicularis oris= moves lips and mouth “kissing muscle”, temporalis: helps with chewing

trapezius: extend head, adduct, elevate or depress scapula

latissimus dorsi: extend, adduct, and rotate arm, origin: scapula, vertebrae, ilium, insertion: humerus

deltoid: origin: clavicle insertion: humerus, abduct, flex ,and extend the arm

pectoralis major: flexes, adducts, and rotates arm, origin: clavicle, insertion: humerus

biceps brachii: flexes elbow join, origin: scapula, insertion: radius

triceps brachii: extend elbow joint

rectus abdominous: flexes abdomen, origin: pubis, insertion: ribs and xiphoid process

external oblique: compress abdomen

intercostals: elevate and depress ribs

diaphragm: respiration (inspiration)

forearm muscles: flexor carpi ulnaris- flexes wrist, extensor carpi ulnaris- extends wrist

extensor and flexor digitorums: metacarpal and phalange muscles

Gluteus maximus and medius: extends and rotates thigh laterally, origins: ilium, sacrum and coccyx, insertion: femur

rectus femoris, vastus lateralis, vastus medialis: flexes thigh, extends lower leg

adductors and gracilis: adducts and flexes thigh and hip

sartorius (longest muscle):

biceps femoris and semitendinosus (hamstring muscles): extends thigh and flex

gastrocnemius and soleus- plantar flexes foot and flex lower leg, gastrocnemius- origin: femur Insertion: calcaneus

tibialis and fibularis: flexes and inverts foot

Warm up 3/24: define tendon and ligament and give examples

• tendon: a band of fibrous tissue that attaches muscle to bone ex: Achilles tendon

• ligament: bone-to-bone

Diseases and disorders

• loss of muscle tone

  • - usually caused by an underlying disease or injury like cerebral palsy, muscular dystrophy, or paralysis)

• atrophy- reduction in size and strength of the muscle

• contracture- severe tightening of muscle resulting in permanent bending of a joint

diseases and disorders of the muscular system

• muscle strains- torn/stretched muscles or tendons. grades I, II, III (III being the worst)

• cause: fatigue, injury or overuse

• symptoms: pain/ swelling from bleeding inside the muscle

• treatment- rest, elevation, muscle relaxants, and alternating hot and cold

• fibromyalgia- muscle disorders with chronic pain in specific muscle sites

• can be affected by stress, weather, and poor physical fitness

• symptoms include fatigue, headache, and feelings of numbness and tingling but no inflammation

• muscular dystrophy- an inherited disease in which muscles gradually deteriorate

• symptoms: painless, progressive muscle weakness

• no cure

• treatment- medication, physical therapy, and surgery

Warm up 3/25: describe the 3 types of muscle (indicate the # of nuclei, striations, locations, voluntary/involuntary)

-smooth: lines the organs, involuntary, one nucleus

-skeletal: striated, voluntary, multinucleated

-cardiac:

Warm-up: define the following terms and what they allow the muscles to do.

1. fascia- sheet of tough fibrous tissue that wraps around an individual muscle fiber, sustainability and protect

2. myofibrils- muscle fibers, allow for contraction of muscles

3. sarcomeres- basic unit made up of myosin and actin, sliding filament theory