Eric Harwell

1
Muscle Tissue

• Eric Harwell
• Growth and Development
• ANSC 590
• Fall 2008

2
Muscle Function

• Serves several purposes
• Basis of all movement of the body.
• Examples
• Locomotion
• Digestion
• Vision
• Circulation
• And many other biological activities
• These are accomplished by the ability of muscle
  to contract and relax.

3
The use of Muscles

• In the body, two vital functions include
• Conversion of chemical energy into mechanical.
• (not very efficient, 75 lost as heat)
• Maintenance of body temperature.
• Other functions of muscle in the body include
• Communication
• via voice related structures
• Various body gestures and movements

4
The use of Muscle

• Muscle is converted to meat.
• Excellent source of protein and many other
  nutrients
• In developing countries, meat animals contribute
  significantly to the quality of the human diet.
• Optimizing muscle growth for meat production is a
  major goal of the meat industry.
• Although many other animal tissues are used for
  consumption, skeletal muscle is the most
  significant component of animal production.

5
Types of Muscle Tissue in the Body

• Three types
• Classified by their microstructure and means in
  which they are stimulated.
• Tissues contain unique set of proteins capable of
  interacting by sliding past each other
  (contraction)
• Smooth, Involuntary
• Arteries, veins, gastrointestinal tract
• Striated, Involuntary
• Cardiac muscle
• Striated, Voluntary
• Skeletal muscle

6
Types of muscle tissue in the body

• Skeletal Muscle
• Cardiac Muscle
• Smooth Muscle

7
Skeletal Muscle

• Many shapes and sizes
• Examples
• Semimembranosus is one of the largest muscles in
  the animal.
• Lower leg flexor muscles are 10,000 times lighter
  than semimembranosus.
• Semitendonosis muscle is long cylindrical
  muscle.
• Massater muscle in jaw is circular shape.

8
Organization of Muscle Tissue

• Large cells bundled together in large network of
  connective tissue.
• Merge with each other to transmit greater
  contractile force to provide movement.

9
Organization of Muscle Tissue

• Connective Tissue
• Basis of all structural integrity of muscles.
• Several layers
• Epimysium outer most layer of connective tissue.
• Seperates muscles into distinct units.
• Provides avenues for nerves and blood vessels to
  enter/exit muscles.

10
Organization of Muscle Tissue

• Connective Tissue
• Perimysium contain a number of smaller muscle
  fiber bundles.
• Several bundles encased within the epimysium
  layer.
• intramuscular fat, marbling, is deposited
  between these bundles.

11
Organization of muscle tissue

• Connective Tissue
• Endomysium surrounds muscle fibers within each
  perymisial bundle.
• Considered the major component of meat tenderness
  and changes with age.
• Lies adjacent to the muscle cell membrane.

12
Muscle Fiber

• Encased in the endomysium layer.
• Multinucleated fiber is the basic cellular
  structure of muscle or meat.
• May extend the entire or partial length of the
  muscle.

13
Muscle Fiber

• Cell Membrane
• Sarcolemma
• Similar functions to other cell membranes of
  other cell types.
• Unique to sarcolemma
• Small invaginations spaced along surface of the
  cell which act as communication channels.

14
(No Transcript)
15
Myofibrils

• The inner making of the skeletal muscle cell.
• Unique microfilamentous organelles of muscle
  fibers.
• Highly organized structures running entire length
  of the cell.
• Bathed in cytoplasm, which is rich in protein.
• Muscle cells contain 1,000-2,000 myofibrils.

16
Sarcomere

• Smallest contractile unit of the muscle.
• Repeated structure represents the organization of
  myofibrils.
• made of many proteins
• that are directly involved in contraction.
• that regulate interactions of filaments
• that are required to stabalize the lattice work
  structure of the cell.
• A sarcomere is measure from Z-line to Z- line and
  mark the boundary or adjacent sarcomeres.
  10,000 sarcomeres make up a myofibril.

17
Sarcomere

• Aligned across entire muscle fiber, altering
  light and dark banding patterns are readily
  apparent microscopically.
• Straited appearance is the hallmark of skeletal
  and cardiac muscle.
• Length of sarcomere is related to tenderness
• Shorter greater overlap of thick and thin
  filaments tougher meat.
• Longer less overlap of thick and thin filaments
  tender meat.

18
Sarcomere

• Illustrated Structure of a sarcomere
• A- Band Dense area in the middle, where thick
  filaments are located.
• H- Zone small area within the A-band where thin
  filaments terminate from each half of the
  sarcomere, and only thick filaments are present.
• I- Band consists of Z-line and thin filaments
  from adjacent sarcomeres.
• Shortens during contraction as a result of
  sliding filaments.

19
(No Transcript)
20
Contractile proteins

• Actin and myosin
• Myosin
• Most abundant contractile protein.
• Occupies 80-87 of volume of muscle fibers.
• Is the real power component of muscle
  contraction because its unique structure allows
  it to pull actin filaments together.
• Actin
• Second most abundant contractile protein.
• Consists of nearly 20 of total myofibrillar
  protein.
• broken down is made of G-actin and F-actin.
• binds to myosin to form actomyosin and contract.

21
(No Transcript)
22
(No Transcript)