Muscular System

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Muscular System

• Mrs. Hammac
• Health

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What Muscles Do

• The muscular system allows for voluntary and
  involuntary movements.

• Your muscular system allows you to move.

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How Muscles Work

• When bundles of muscles are stimulated by nerve
  impulses, or signals, they contract, or shorten.
• When they relax, the bundles extend, or stretch.

Functions Movement Stability Control of body
openings and passages Heat production
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Skeletal Muscle
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Types of Muscles
Three Types of Muscle Tissue
Smooth Muscle
Skeletal Muscle
Cardiac Muscle
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What Muscles Do

• Involuntary muscle movements help you breathe,
  make your heart beat, and move food through your
  digestive system.

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Functions of Muscle Stability

• Hold bones tightly together
• Stabilize joints
• Small muscles hold vertebrae together
• Stabilize the spinal column

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Functions of Muscle Control of Body Openings and
Passages

• Sphincters
• Valve-like structures formed by muscles
• Control movement of substances in and out of
  passages
• Example
• A urethral sphincter prevents or allows urination

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Functions of Muscle Heat Production

• Heat is released with muscle contraction
• Helps the body maintain a normal temperature
• Moving your body can make you warmer if you are
  cold

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Types of Muscles

• Smooth muscles are involuntary muscles.

Smooth muscles
Muscles that act on the lining of the bodys
passageways and hollow internal organs
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Types of Muscle Tissue Smooth Muscle

• Multi-unit smooth muscle
• In the iris of the eye and walls of blood vessels
• Responds to neurotransmitters and hormones
• Visceral smooth muscle
• In walls of hollow organs
• Responds to neurotransmitters AND
• Stimulate each other to contract so that muscle
  fibers contract and relax together in a rhythmic
  motion peristalsis

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Types of Muscle Tissue Smooth Muscle (cont.)

• Peristalsis rhythmic contraction that pushes
  substances through tubes of the body
• Neurotransmitters for smooth muscle contraction
• Acetylcholine
• Norepinephrine
• Will cause or inhibit contractions, depending on
  smooth muscle type

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Types of Muscles

• Cardiac muscle is involuntary and is responsible
  for the contraction of your heart. Your heart
  beats 100,000 times each day.

Cardiac muscle
A type of striated muscle that forms the wall of
the heart
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Types of Muscle Tissue Cardiac Muscle

• Intercalated discs
• Connect groups of cardiac muscle
• Allow the fibers in the groups to contract and
  relax together
• Allows heart to work as a pump
• Self-exciting does not need nerve stimulation
  to contract
• Nerves speed up or slow down contraction

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Types of Muscles

• Most of your muscle tissue is skeletal, and
  almost all skeletal muscles are under voluntary
  control.

Skeletal muscles
Muscles attached to bone that cause body
movements
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Types of Muscle Tissue Skeletal Muscle

• Muscle fibers respond to the neurotransmitter
  acetylcholine
• Causes skeletal muscle to contract
• Following contraction, muscles release the enzyme
  acetylcholinesterase
• Breaks down acetylcholine
• Allows muscle to relax

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Apply Your Knowledge
True or False ___ Skeletal muscles are attached
to bones by ligaments. __ Contractions of smooth
muscle produce movement of organ contents. ___
Cardiac muscle produces atrial and ventricular
contractions. ___ Sphincters control movement of
substances out of passages. ___ Heat is released
as muscles relax.
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Apply Your Knowledge
ANSWER
True or False ___ Skeletal muscles are
attached to bones by ligaments. __ Contractions
of smooth muscle produce movement of organ
contents. ___ Cardiac muscle produces atrial and
ventricular contractions. ___ Sphincters control
movement of substances out of passages. ___ Heat
is released as muscles relax.
tendons
F
T
T
in and out
F
contract
RIGHT!
F
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What Muscles Do

• Skeletal muscles work in pairs to produce
  movement.

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Caring for Your Muscles
Get regular exercise.
Eat high protein foods to build muscle.
Practice good posture to strengthen back muscles.
Use proper equipment and wear appropriate
clothing to protect muscles during any physical
activity.
Warm up properly and stretch before exercising,
and cool down after exercising to prevent injury.
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Understanding Muscular Problems

• Bruises are areas of discolored skin that appear
  after an injury that causes the blood vessels
  beneath the skin to rupture and leak.
•  
• Large bruises can be treated with an ice pack to
  reduce initial swelling.

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Understanding Muscular Problems

• Muscle strains or sprains result when muscles are
  stretched or partially torn from overexertion.
• Apply ice to strains to reduce swelling, and rest
  the affected area.

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Understanding Muscular Problems

• Tendinitis can be caused by injury, overuse, or
  natural aging.

Tendinitis
The inflammation of a tendon
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Understanding Muscular Problems

• Hernias commonly occur in the abdomen from
  straining to lift a heavy object. Surgery can
  usually repair hernias.

Hernia
An organ or tissue protrudes through an area of
weak muscle
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Understanding Muscular Problems

• Muscular dystrophy is an inherited disorder in
  which skeletal muscle fibers are progressively
  destroyed.
• There is no cure, but with early detection,
  muscle weakness can be delayed through exercise
  programs.

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Muscle Strains and Sprains

• Strains injuries due to over-stretched muscles
  or tendons
• Sprains more serious injuries that result in
  tears to tendons, ligaments, and/or cartilage of
  joints
• RICE is recommended treatment for either
• Rest
• Ice
• Compression
• Elevation

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Muscle Strains and Sprains (cont.)

• Prevention
• Warm up muscles
• A few minutes before an intense activity raises
  muscle temperature and makes muscle more pliable
• Stretching
• Improves muscle performance and should always be
  done after the warm-up or after exercising
• Cooling down or slowing down
• Before completely stopping prevents pooling of
  blood in the legs and helps remove lactic acid
  from muscles

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Aging and the Musculoskeletal System

• Contractions become slower and not as strong
• Dexterity and gripping ability decrease
• Mobility may decrease
• Assistive devices helpful
• Routine exercise
• Swimming
• Physical therapy

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Apply Your Knowledge
The doctor has told your patient that his son has
muscular dystrophy disorder. What is muscular
dystrophy?
ANSWER Muscular dystrophy is an inherited
disorder characterized by muscle weakness and a
loss of muscle tissue.
Good Job!
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In Summary

• Skeletal muscles
• Voluntary control
• Produce movement in conjunction with skeletal
  system
• Help stabilize joints
• Participate in heat production

• Smooth muscles
• Involuntary control
• Control body openings and passages
• Cardiac muscles
• Involuntary control
• Responsible for pumping action of the heart

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Sources

• http//graphics8.nytimes.com/images/2007/08/01/hea
  lth/adam/19917.jpg
• http//www.sport-fitness-advisor.com/images/muscle
  _anatomy.jpg
• http//images.encarta.msn.com/xrefmedia/sharemed/t
  argets/images/pho/t790/T790539A.jpg
• http//clcpages.clcillinois.edu/home/bio567/pages/
  newtissues/Skeletal20muscle2003a.jpg
• http//www.sciencelearn.org.nz/var/sciencelearn/st
  orage/images/contexts/see_through_body/sci_media/c
  ardiac_muscle/8558-1-eng-NZ/cardiac_muscle_full_si
  ze_landscape.jpg