3. MUSCULAR TISSUE
The contractile capacity (ie shortening) of some specialized cells derives from the MOTIVE FORCE that arises from the interaction of the
contractile proteins ACTIN and MYOSIN.
UNICELLULAR contractile units:
- myoepithelial cells: glands, around acini glands, help secretion
- pericytes: around the vessels
- myofibroblasts: cells with contractile capacity and secretory function
MULTICELLULAR contractile units: distributed in the three types of muscle tissue
- SKELETAL muscle cells: they are responsible for the movement of the skeleton, the eyeball and the tongue
- SMOOTH muscle cells: give life to smooth muscle
- CARDIAC muscle cells: they have intermediate functional and structural characteristics compared to the previous ones and are
responsible for the continuous and rhythmic contractility of the heart, autonomous contraction
these three tissues are united by streaks and have the same functional unit (sarcomere)
The contractile capacity, i.e. the capacity to shorten, of the muscle cells gives the body the following functions:
- locomotion
- contraction
- pumping and other propulsive movements
specific terms for muscle cells
SKELETAL MUSCULATURE:
The skeletal muscle cell is derived from the somatic mesoderm. The muscle FIBERS are arranged parallel to each other, while the
capillaries are located in the intercellular spaces.
The FUNCTIONS are:
- voluntary movements of the different parts of the skeleton
- maintenance of posture
- litigation and protection of internal bodies
- orifice check
The MUSCULAR SKELETAL cell is: - elongated - cylindrical - multinucleated - striated
Depending on:
- of the fibers (the single fiber is covered by endomysium)
- myoglobin content (protein that binds O2)
- number of mitochondria
- concentration of various enzymes
- speed of contraction
muscle fibers can be:
RED. slow twitch fibers: they are small in diameter, high in myoglobin (proteins that carry oxygen), can sustain prolonged and intense
contractions (high fatigue tolerance) without these fibers we would not be able to follow simple movements such as sitting, walking, standing
standing. Oxidative metabolism
WHITE. fast, are thicker fibers and have higher growth potential, low myoglobin content, and few mitochondria. support short and intense
contractions. generate ATP by anaerobic glycolysis, glycogen is the main form of energy
INTERMEDIATE. they are intermediate in diameter, contain a lot of myoglobin, have a high glycogen content and generate a lot of ATP.
they are extremely adaptable fibers, both in the short and long term
Most skeletal muscles are made up of all three fiber types.
The muscle fibers of any motor unit are all of the same type and there is activation of a certain unit based on the type of physical effort to
which
the body meets.
Muscle contractions are of two types. depends on the variation in muscle length.
, stante
BAVAAI BANDA I BANDAI
AA H
accorciata
A
ARCOMERO
The contractile capacity (ie shortening) of some specialized cells derives from the MOTIVE FORCE that arises from the interaction of the
contractile proteins ACTIN and MYOSIN.
UNICELLULAR contractile units:
- myoepithelial cells: glands, around acini glands, help secretion
- pericytes: around the vessels
- myofibroblasts: cells with contractile capacity and secretory function
MULTICELLULAR contractile units: distributed in the three types of muscle tissue
- SKELETAL muscle cells: they are responsible for the movement of the skeleton, the eyeball and the tongue
- SMOOTH muscle cells: give life to smooth muscle
- CARDIAC muscle cells: they have intermediate functional and structural characteristics compared to the previous ones and are
responsible for the continuous and rhythmic contractility of the heart, autonomous contraction
these three tissues are united by streaks and have the same functional unit (sarcomere)
The contractile capacity, i.e. the capacity to shorten, of the muscle cells gives the body the following functions:
- locomotion
- contraction
- pumping and other propulsive movements
specific terms for muscle cells
SKELETAL MUSCULATURE:
The skeletal muscle cell is derived from the somatic mesoderm. The muscle FIBERS are arranged parallel to each other, while the
capillaries are located in the intercellular spaces.
The FUNCTIONS are:
- voluntary movements of the different parts of the skeleton
- maintenance of posture
- litigation and protection of internal bodies
- orifice check
The MUSCULAR SKELETAL cell is: - elongated - cylindrical - multinucleated - striated
Depending on:
- of the fibers (the single fiber is covered by endomysium)
- myoglobin content (protein that binds O2)
- number of mitochondria
- concentration of various enzymes
- speed of contraction
muscle fibers can be:
RED. slow twitch fibers: they are small in diameter, high in myoglobin (proteins that carry oxygen), can sustain prolonged and intense
contractions (high fatigue tolerance) without these fibers we would not be able to follow simple movements such as sitting, walking, standing
standing. Oxidative metabolism
WHITE. fast, are thicker fibers and have higher growth potential, low myoglobin content, and few mitochondria. support short and intense
contractions. generate ATP by anaerobic glycolysis, glycogen is the main form of energy
INTERMEDIATE. they are intermediate in diameter, contain a lot of myoglobin, have a high glycogen content and generate a lot of ATP.
they are extremely adaptable fibers, both in the short and long term
Most skeletal muscles are made up of all three fiber types.
The muscle fibers of any motor unit are all of the same type and there is activation of a certain unit based on the type of physical effort to
which
the body meets.
Muscle contractions are of two types. depends on the variation in muscle length.
, stante
BAVAAI BANDA I BANDAI
AA H
accorciata
A
ARCOMERO
