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The Muscular System
Support Systems
Unit 2
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
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
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
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
Cardiac Muscle Tissue
Smooth Muscle
• Located in walls of hollow internal
surfaces such as:
– blood vessels
– urinary bladder
- stomach
- intestines
• Non-striated in appearance
• Involuntary (typically)
• Contractions usually move things
along, from point A to point B
(peristalsis)
Smooth Muscle Tissue
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
Skeletal Muscle Tissue
Connecting Tissues
Tendon – muscle to bone
Ligament- bone to bone
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
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
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
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
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
Anterior Skeletal Muscles
Posterior Skeletal Muscles
Diseases and
Disorders of the
Muscular System
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).
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
Three Degrees of Sprains
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.
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.
Careers
•
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Orthopedic Surgeon
Certified Athletic Trainer
Medical Illustrator
Massage Therapist
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
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
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
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
Vocabulary- word parts
• My/o- muscle (myofibril is a muscle fiber)
•
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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 (dysphagiadifficulty swallowing)
• -algia- suffix, pain (myalgia- muscle pain)
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