LECTURE SIX :- PHYSIOLOGY OF THE MUSCULAR SYSTEM
Muscle physiology is the study of muscle function. A muscle is a bundle of fibers
that contract to produce heat, posture, and motion, either of internal organs or of the
organism itself. Muscle physiology studies the physical, mechanical, and biochemical
aspects of muscles in development, fiber structure, muscle structure, contraction, and
strength-building.
The body has three types of muscle:
cardiac, smooth, and skeletal.
Skeletal muscle is a voluntary muscle, or a muscle that can be consciously controlled,
characterized by even striations, or stripes. Skeletal muscle attaches to bones to effect
movement of the skeleton for purposes such as posture and locomotion.
Smooth muscle is an involuntary muscle, marked by a lack of striations, that effects
movement in the internal organs.
Cardiac muscle is an involuntary, unevenly striated muscle that composes the heart
and causes its contractions, or the beating of the heart.
Functions of the Muscular System
, Producing movement is a common function of all muscle types, but skeletal muscle
plays three other important roles in the body as well.
1. Producing movement. Mobility of the body as a whole reflects the
activity of the skeletal muscles, which are responsible for all locomotion;
they enable us to respond quickly to changes in the external environment.
2. Maintaining posture. We are rarely aware of the skeletal muscles that
maintain body posture, yet they function almost continuously, making one
tiny adjustment after another so that we can maintain an erect or seated
posture despite the never-ending downward pull of gravity.
3. Stabilizing joints. As the skeletal muscles pull on bones to cause
movements, they also stabilize the joints of the skeleton; muscle tendons
are extremely important in reinforcing and stabilizing joints that have
poorly fitting articulating surfaces.
4. Generating heat. The fourth function of muscle, generation of body heat,
is a by-product of muscle activity; as ATP is used to power muscle
contraction, nearly three-quarters of its energy escape as heat and this heat
is vital in maintaining normal body temperature.
Muscle physiology is the study of muscle function. A muscle is a bundle of fibers
that contract to produce heat, posture, and motion, either of internal organs or of the
organism itself. Muscle physiology studies the physical, mechanical, and biochemical
aspects of muscles in development, fiber structure, muscle structure, contraction, and
strength-building.
The body has three types of muscle:
cardiac, smooth, and skeletal.
Skeletal muscle is a voluntary muscle, or a muscle that can be consciously controlled,
characterized by even striations, or stripes. Skeletal muscle attaches to bones to effect
movement of the skeleton for purposes such as posture and locomotion.
Smooth muscle is an involuntary muscle, marked by a lack of striations, that effects
movement in the internal organs.
Cardiac muscle is an involuntary, unevenly striated muscle that composes the heart
and causes its contractions, or the beating of the heart.
Functions of the Muscular System
, Producing movement is a common function of all muscle types, but skeletal muscle
plays three other important roles in the body as well.
1. Producing movement. Mobility of the body as a whole reflects the
activity of the skeletal muscles, which are responsible for all locomotion;
they enable us to respond quickly to changes in the external environment.
2. Maintaining posture. We are rarely aware of the skeletal muscles that
maintain body posture, yet they function almost continuously, making one
tiny adjustment after another so that we can maintain an erect or seated
posture despite the never-ending downward pull of gravity.
3. Stabilizing joints. As the skeletal muscles pull on bones to cause
movements, they also stabilize the joints of the skeleton; muscle tendons
are extremely important in reinforcing and stabilizing joints that have
poorly fitting articulating surfaces.
4. Generating heat. The fourth function of muscle, generation of body heat,
is a by-product of muscle activity; as ATP is used to power muscle
contraction, nearly three-quarters of its energy escape as heat and this heat
is vital in maintaining normal body temperature.
