Download 1. Muscles

LECTURE №6
MYOLOGY
(section of anatomy)
total body cover
locomotor apparatus
passive part
active part
MUSCULAR SYSTEM - A SET OF SKELETAL
MUSCLES OF DEVELOPING COMMON GERMS MYOTOMES (DORSAL MESODERM), BUILT MAINLY OF
STRIATED MUSCLE TISSUE, CAPABLE OF ARBITRARY
REDUCTION, WHICH LEADS TO MOVEMENT OR
MAINTENANCE OF POSES.
Functions:
- movement in space by acting on bone levers (locomotion),
- maintenance of posture, balance (static), manipulation,
breathing and swallowing movements, oculomotor
function and others,
- participated in the formation of the walls of the cavities of
the body,
- metabolic,
- at a part in kinesthesia (perception of the position and
body movements).
The human body has more than 400 skeletal muscles that have
a specific position. Muscles are about 35-40% of total body
weight.
1. Muscles are attached to the skeleton.
2. As a muscle contracts, it pulls on the skeleton,
causing movement.
3. Muscles are attached to bones by tough
connective tissues called tendons.
a. Tendons connect muscle to bones.
Movement: Vertebrates and Arthropods
4. Muscle attachment sites to bone:
a. Origin: During contraction there is no
movement.
b. Insertion: During contraction the bone
movement.
5. Paired Muscles
a. Muscles that cause locomotion work in pairs
(or at least in two opposing groups)
b. Example: The biceps (flexion/bending) and
triceps (extension/straightening) work
opposite each other to cause motion.
Types of Vertebrate Muscles
1. Striated Skeletal Muscle
a. Striped appearance when viewed
under a microscope.
b. Each skeletal muscle fiber is
stimulated by just one nerve.
Types of Vertebrate Muscles
c. Importance for locomotion/movement.
d. Under voluntary control.
Types of Vertebrate Muscles
2. Nonstriated Smooth Muscle
a. Moves many of the internal parts of
the body.
Types of Vertebrate Muscles
b. Makes up the walls of the hollow organs of
the body, such as the digestive tract.
(Peristalsis)
c. Also seen in blood vessels.
d. Under involuntary control.
Types of Vertebrate Muscles
3. Cardiac Muscle (The Heart)
a. The heart is composed of this type of muscle.
b. Under involuntary control (contracts
rhythmically)
Contraction of Vertebrate
Skeletal Muscle
1. Muscles consist of bundles of fibers
that are made up of smaller fibrils.
Meaning of endomysium and
perimysium
1. Stroma forms a body;
2. Muscle fibers are formed into bundles, the
bundles in the muscle;
3. Since endomysium surrounding sarcolemma and
grow together with it, while reducing the muscle
fiber, which shortens and thickens, prevents tearing
fibers, and thus regulates the contraction.
Contraction of Vertebrate
Skeletal Muscle
2. Fibrils are made up of two types of
protein filaments:
(1) Actin (Thin Filaments)
(2) Myosin (Thick Filaments)
Contraction of Vertebrate
Skeletal Muscle
3. The thin filaments are anchored to vertical
bands called Z lines.
4. The part of a fibril from one Z line to the next
Z line to next is called a sarcomere.
The Sliding Filament Hypothesis
1. Actin and myosin filaments slide
over one another to shorten the
fibrils during muscle contractions.
Development of the musculoskeletal system
Formation of somites
Isolation myotomes
composed somites
Myotome differentiation (3-5 weeks)
somites
myoblasts
dermatome
myotome
sclerotome
Formation of somites
Myoblast migration (give rise
to the muscles of
extremities)
Isolation in the somites
dermatome, sclerotome,
myotome
Each myotome (and dermatome) in the moment their separation
corresponds portion of the neural tube - nevromer from which to him
are suitable fibers future spinal nerves. Each follows the nerve muscle
during its movements and changes. Therefore, the nature of innervation
of muscles depending on where it devolopment.
Sources muscle development
1. Preotic myotomes
2. Mesoderm of
branchial arches
3. Occipital myotomes
4. Trunk myotomes
Formation located ventral muscles
• In the process of
development is an
increase in the ventral
myotomes direction,
divide them into
groups, splitting into
individual muscles, the
formation of long
muscles by intergrowths
of neighboring
myotomes.
MUSCLES
Truncifugal
Autochthonous
(from the trunk
(proper)
to the limbs)
Truncipetal
(from the
limbs to the
trunk)
Muscle movement during embryonic development
Muscle as an organ:
- has a position in the body
- has its own, distinct other forms of
- consists of muscle and other tissues, - has its own nerve
and blood supply - - develops from myotome
- motor and performs other functions
Auxiliary apparatus
- Fascia;
- Musculo-fascial sheath;
- Bursa;
- Synovial tendon sheath;
- Muscular blocks;
- Sesamoid bones.
Hurry
to learn
Muscles!