The Muscular System

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The Muscular System

• Support Systems
• Unit 2

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Functions of the Muscular System

• Heat Production (thermogenesis)
• Breaking of ATP during muscle contraction
• Movement Facilitation
• Muscles pull on the skeletal levers
• Structure (postural support)
• Muscles hold parts of the skeleton in place
• Protection of Internal Organs
• The abdominal muscles are thick and protect the
  abdominal and pelvic cavity organs

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Types of Contractibility

• Voluntary- contractions controlled by conscious
  thought or will
• Involuntary- contract due to unconscious impulses
  sent by the autonomic nervous system or certain
  specialized cells or hormones

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Muscle Appearance

• Striated- stripes, muscles that on a microscopic
  level have cross fiber stripes
• Non-striated- Not having stripes, muscles cells
  that microscopically have a smooth appearance

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Cardiac Muscle

• Forms the bulk of heart wall (Myocardium)
• Striated
• Involuntary (typically)
• Cardiac fibers typically have a centrally located
  nucleus
• Intercalated discs
• Strengthens cardiac muscle tissue
• Allows for special wringing muscle contraction

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Cardiac Muscle Tissue
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Smooth Muscle

• Located in walls of hollow internal surfaces such
  as
• blood vessels - stomach
• urinary bladder - intestines
• Non-striated in appearance
• Involuntary (typically)
• Contractions usually move things along, from
  point A to point B (peristalsis)

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Smooth Muscle Tissue
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Skeletal Muscle

• Attached to bones
• Striated appearance under a microscope
• Voluntary control (conscious control)
• Allow for postural support and movement of body
  parts, both axial and appendicular

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Skeletal Muscle Tissue
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Connecting Tissues

• Tendon muscle to bone

• Ligament- bone to bone

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Motions

• Peristalsis- a wave like motion by smooth muscle
  to advance substances
• Abduction- movement away from midline
• Adduction- movement towards midline
• Flexion- decreasing a joint angle
• Extension- increasing a joint angle
• Hyperextension- extension past normal extension,
  or past anatomical position

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Motions

• Plantarflexion- specific to ankle motion,
  pointing the toes
• Dorsiflexion- specific to ankle motion, pulling
  the toes towards the shin
• Supination- turning palm up
• Pronation- turning palm down
• Rotation- movement around an axis

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Location and Function of Skeletal Muscles

• Biceps brachii- anterior surface of arm between
  the shoulder and elbow, flexes the elbow
• Triceps brachii- posterior aspect of arm between
  the shoulder and elbow, extends the elbow
• Trapezius- attaches to the spine from the occiput
  through the thoracic region and to the spine of
  the scapula, extends or hyperextends the head and
  neck, (also helps with shoulder retraction and
  elevation and depression)
• Deltoid- covers the cap of the shoulder, abducts
  the arm
• Diaphragm- connects to the lower ribs and runs
  through the entire body, deflects the diaphragm
  inferiorly increasing volume of the thoracic
  cavity

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Location and Function of Skeletal Muscles

• Pectoralis major- attaches to the upper ribs
  along the sternum and to the humerus, adducts the
  arm
• Latissimus dorsi- attaches along mid to lower
  spine and pelvic and to the humerus, extends a
  flexed arm or hyperextends the arm from the
  anatomical position
• Rectus abdominus- attaches to the lower ribs and
  to the pelvic anteriorly, flexes the lumbar spine
  
• Gastrocnemius-attaches to the tibia and lower
  femur and uses the achilles tendon to attach to
  the calcaneous (heel bone), plantar flexes the
  ankle when the knee is in extension

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Location and Function of Skeletal Muscles

• Soleus- attached deep to the gastrocnemius on the
  tibia and uses the achilles tendon to attach to
  the calcaneous, plantarflexes the ankle when the
  knee is bent
• Hamstrings- posterior thigh between the hip and
  knee, flexes the knee
• Quadriceps- anterior thigh between the hip and
  knee, extends the knee
• Gluteus maximus- posterior pelvis, extends a
  flexed thigh or hyperextends the thigh from the
  anatomical position

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Anterior Skeletal Muscles
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Posterior Skeletal Muscles
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Diseases and Disorders of the Muscular System
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Tendonitis

• Tendonitis is characterized by Inflammation of
  the tendons due to overuse or age-related changes
  of the tendon.
• It is common in individuals who begin a new
  exercise or increase their level of exercise.
• Age-related tendonitis is due to the loss of
  elasticity and the ability of the tendon to glide
  smoothly.
• Treatment includes rest, ice, compression, and
  elevation (RICE).

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Sprain

• A sprain is an injury to a ligament, which is the
  fibrous tissue that connects bones to other
  bones.
• There are three grades of sprains
• 1st Degree Sprain stretching of ligaments
• 2nd Degree Sprain partial tearing of ligaments
• 3rd Degree Sprain complete tear of ligaments

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Three Degrees of Sprains
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Strains

• Muscle strain or muscle pull or even a muscle
  tear implies damage to a muscle or its attaching
  tendons.
• This can occur due to excessive pressure on
  muscles during the course of normal daily
  activities, with sudden, quick heavy lifting,
  during sports, or while performing work tasks.

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Degrees of Muscle Strains

• First degree strain - a mild strain when only a
  few muscle fibers are stretched or torn. The
  injured muscle is tender and painful, but has
  normal strength.
• Second degree strain - a moderate strain with a
  greater number of injured fibers. There is more
  severe muscle pain and tenderness. There is also
  mild swelling, some loss of strength, and a
  bruise may develop.
• Third degree strain - this strain tears the
  muscle all the way through. There is a total loss
  of muscle function.

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Careers

• Orthopedic Surgeon
• Certified Athletic Trainer
• Medical Illustrator
• Massage Therapist

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Orthopedic Surgeon

• Medical Doctor who specializes in musculoskeletal
  ailments including acute, chronic, traumatic and
  overuse injuries
• Performs surgeries on musculoskeletal disorders
  such as ACL tears, Knee replacements, Scoliosis
  surgery
• Attends 4 year undergrad 4 year medical school
  5 year orthopedic residency program 1 year
  fellowship
• Salary- 300,000
• Arthroscopic surgery

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Certified Athletic Trainer

• Responsible for prevention, recognition,
  evaluation, immediate care and rehabilitation of
  injuries
• Work at high schools, universities, professional
  sports, gyms, industry, military, hospitals and
  clinics
• Bachelors Degree
• 35,000
• Athletic Training- Smooth Professional

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Medical Illustrator

• Artists who have detailed knowledge of the human
  body
• Create graphic representations of medical or
  biological subjects for textbooks, pamphlets,
  exhibits, films, legal procedures, teaching
  models
• Pre-med/ Art Major
• Masters of Medical Illustrating
• Salary - 33,000-60,000
• Job outlook is small and competitive, BUT growing
  because of technology

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Massage Therapist

• Manipulate patients body with pressure, tension
  or vibration manually or with mechanical aids
• Work in hospitals, nursing homes, sports and
  fitness centers, spas, beauty salons, cruise
  ships, private offices
• Graduate from accredited Massage school (8 months
  to 12 months)and pass License exam
• Can specialize in pediatric massage, sports
  massage.
• Salary varies widely
• Where do MT work and how much do they make
• Sports Massage

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Vocabulary- word parts

• My/o- muscle (myofibril is a muscle fiber)
• Ab- prefix, away (abduction)
• Ad- prefix, towards (adduction)
• Bi- prefix, two (biceps)
• Tri- prefix, three (triceps)
• Quad- prefix, four (quadriceps)
• Contra- prefix, opposite or against
  (contralateral- pertaining to the other side)
• Dys- prefix, bad, difficult, or painful
  (dysphagia- difficulty swallowing)
• -algia- suffix, pain (myalgia- muscle pain)

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Vocabulary

• Ligament- connective tissue that holds bone to
  bone
• Tendon- connective tissue that hold muscle to
  bone
• Tendonitis- inflammation of a tendon
• Sprain- stretch or tear of a ligament
• Strain- stretch or tear of a muscle or tendon
• Myocardium- heart muscle
• Thermogenesis- heat production
• Striations- stripes
• MRI- Magnetic Resonance imaging