The Muscular System Flashcards
The muscular system is responsible for…
The muscular system is responsible for the movement of the human body. Attached to the bones of the skeletal system are about 700 named muscles that make up roughly half of a person’s body weight. Muscle tissue is also found inside of the heart, digestive organs, and blood vessels.
Muscle Types
- Visceral
- Cardiac
- Skeletal
Visceral Muscle
Visceral muscle is found inside of organs like the stomach, intestines, and blood vessels.
The weakest of all muscle tissues, visceral muscle makes organs contract to move substances through the organ. it is known as involuntary muscle-it cannot be directly controlled by the conscious mind.
Visceral: smooth or striated
The term “smooth muscle” is often used to describe visceral muscle because it has a very smooth, uniform appearance when viewed under a microscope. This smooth appearance starkly contrasts with the banded appearance of cardiac and skeletal muscles.
Cardiac Muscle
Found only in the heart, cardiac muscle is responsible for pumping blood throughout the body. INVOLUNTARY. cardiac muscle stimulates itself to contract. Because of its self-stimulation, cardiac muscle is considered to be autorhythmic or intrinsically controlled.
Cardiac: smooth or striated
The cells of cardiac muscle tissue are striated
striated
they appear to have light and dark stripes when viewed under a light microscope. Striations indicate that a muscle cell is very strong
Skeletal Muscle
Skeletal muscle is the only voluntary muscle tissue in the human body-it is controlled consciously. The function of skeletal muscle is to contract to move parts of the body closer to the bone that the muscle is attached to.
Skeletal: smooth or striated
Striated. skeletal muscle fibers are very strong.
Gross anatomy of skeletal muscle
Most skeletal muscles are attached to two bones through tendons. Muscles move by shortening their length, pulling on tendons, and moving bones closer to each other.
Tendon
attach muscle to bone
Names of Skeletal muscles
Skeletal muscles are based on…
based on many different factors, including their location, origin and insertion, number of origins, shape, size, direction, and function.
Location
The rectus abdominis and transverse abdominis, for example, are found in the abdominal region. Some muscles, like the tibialis anterior, are named after the part of the bone (the anterior portion of the tibia) that they are attached to.
Other muscles use a hybrid of these two, like the brachioradialis, which is named after a region (brachial) and a bone (radius).
Origin and Insertion
Some muscles are named based upon their connection to a stationary bone (origin) and a moving bone (insertion). These muscles become very easy to identify once you know the names of the bones that they are attached to. Examples of this type of muscle include
the sternocleidomastoid (connecting the sternum and clavicle to the mastoid process of the skull) and the occipitofrontalis (connecting the occipital bone to the frontal bone).
Number of Origins
Some muscles connect to more than one bone or to more than one place on a bone, and therefore have more than one origin. A muscle with two origins is called a biceps. A muscle with three origins is a triceps muscle. Finally, a muscle with four origins is a quadriceps muscle.
Shape, Size, and Direction.
We also classify muscles by their shapes. For example, the deltoids have a delta or triangular shape.
The muscles whose fibers run straight up and down are the rectus abdominis, the ones running transversely (left to right) are the transverse abdominis, and the ones running at an angle are the obliques.
Function
Muscles are sometimes classified by the type of function that they perform. For example, the flexor group of the forearm flexes the wrist and the fingers. The supinator is a muscle that supinates the wrist by rolling it over to face palm up. In the leg, there are muscles called adductors whose role is to adduct (pull together) the legs.
Groups Action in the Skeletal Muscle
The muscle that produces any particular movement of the body is known as an agonist or prime mover. The agonist always pairs with an antagonist muscle that produces.
Synergists are muscles that help to stabilize a movement and reduce extraneous movements.
They are usually found in regions near the agonist and often connect to the same bones.
agonist
The muscle that produces any particular movement of the body is known as an agonist or prime mover. The agonist always pairs with an antagonist muscle that produces
Synergists
Synergists are muscles that help to stabilize a movement and reduce extraneous movements.
They are usually found in regions near the agonist and often connect to the same bones.
