BIOD 151 A&P MODULE 5 Anatomy of the
Muscular System: Introduction & Muscles of
the Head, Neck, and Trunk
Notice: To optimize your learning in this course, we advise that you complete the labs
and modules as indicated in the BIOD 151 Lab Schedule.
The muscular system and the skeletal system work together to provide movement for
the human body. Muscle tissue is found in three distinct types in the body; skeletal,
smooth, and cardiac.
Skeletal muscles must have a blood and nervous supply to provide movement. Skeletal
muscles are under conscious control, meaning that a person can consciously decide to
use these muscles to complete an action. Communication within the body to coordinate
movement starts in the brain with a message that is sent through the spinal cord and
eventually attaches to a muscle. Peripheral nerves carry the signal from the central
nervous system (brain and spinal cord) to a specific muscle destination to provide
movement. Messages from the central nervous system to a muscle are called a motor
actions. Nerves also carry information from the external environment to the central
nervous system, called sensation or sensory input. (see Figure 5.1 and Figure 5.2) Spinal
nerves combine to form complex networks of peripheral nerves throughout the body.
Figure 5.1 Posterior view of the nervous system. The brain and spinal cord (central nervous
,system) connect to the peripheral nervous system. Examples of peripheral nerves are spinal nerves
(cervical, thoracic, and lumbar), the upper trunk of the brachial plexus, and the radial nerve.
Figure 5.2 Peripheral nerves carry the communication from the central nervous system (brain and
spinal cord) to the muscle. Peripheral nerves also carry information from the environment to the
central nervous system.
Tendons are connective tissues that connect skeletal muscle to bone at each end (see Figure 5.3).
Tendons are flexible, can bend at the joints, and help cushion against sudden
movement. Ligaments are connective tissue that connects bone to bone, helping to
stabilize joints where bones meet.
,Figure 5.3 Skeletal muscles attach to bones via tendons at points called the origin and insertion.
The origin is the fixed point while the insertion is the place that is moved during a muscle
contraction.
All skeletal muscles have an origin, insertion, and action. The origin is the bony site of
attachment which is stationary during the movement. The insertion of a muscle is the
bony site of attachment that is moved by the muscle contraction. (see Figure 5.3)
The origin and insertion can be reversed in different types of movement. For this
module, the standard origin and insertion points are referenced from anatomical
position.
The action of the muscle is what effect is produced by the muscle’s contraction. For
example, the triceps is the primary extensor of the forearm. The innervation is the
peripheral nerve that supplies a muscle with the message from the brain. For example,
the innervation of the biceps brachii is the musculocutaneous nerve. (see Figure 5.4)
, Figure 5.4 Anterior view of the musculocutaneous nerve (blue) innervates the biceps brachii muscle.
Muscles are generally studied in groups. The following muscle list is an overview of
some of the major muscles in the body. Study the location of the muscle in the body.
In addition, if listed, study the origin, insertion, innervation and action of these
muscles.
Muscles of Facial Expression: (See Figure 5.5)
The muscles in this grouping help to facilitate all the actions within the face. All the
varied facial expressions are enabled by these muscles. CN is an abbreviation for
cranial nerve. There are twelve pairs of cranial nerves that originate on the ventral
surface of the brain, controlling muscles and functions of several organs and glands.
Orbicularis oculi
Action: eye closure
Innervation: Facial nerve (CN VII)
Orbicularis oris
Action: mouth closure: closes lips, protrudes lips forward, presses lips against teeth
Muscular System: Introduction & Muscles of
the Head, Neck, and Trunk
Notice: To optimize your learning in this course, we advise that you complete the labs
and modules as indicated in the BIOD 151 Lab Schedule.
The muscular system and the skeletal system work together to provide movement for
the human body. Muscle tissue is found in three distinct types in the body; skeletal,
smooth, and cardiac.
Skeletal muscles must have a blood and nervous supply to provide movement. Skeletal
muscles are under conscious control, meaning that a person can consciously decide to
use these muscles to complete an action. Communication within the body to coordinate
movement starts in the brain with a message that is sent through the spinal cord and
eventually attaches to a muscle. Peripheral nerves carry the signal from the central
nervous system (brain and spinal cord) to a specific muscle destination to provide
movement. Messages from the central nervous system to a muscle are called a motor
actions. Nerves also carry information from the external environment to the central
nervous system, called sensation or sensory input. (see Figure 5.1 and Figure 5.2) Spinal
nerves combine to form complex networks of peripheral nerves throughout the body.
Figure 5.1 Posterior view of the nervous system. The brain and spinal cord (central nervous
,system) connect to the peripheral nervous system. Examples of peripheral nerves are spinal nerves
(cervical, thoracic, and lumbar), the upper trunk of the brachial plexus, and the radial nerve.
Figure 5.2 Peripheral nerves carry the communication from the central nervous system (brain and
spinal cord) to the muscle. Peripheral nerves also carry information from the environment to the
central nervous system.
Tendons are connective tissues that connect skeletal muscle to bone at each end (see Figure 5.3).
Tendons are flexible, can bend at the joints, and help cushion against sudden
movement. Ligaments are connective tissue that connects bone to bone, helping to
stabilize joints where bones meet.
,Figure 5.3 Skeletal muscles attach to bones via tendons at points called the origin and insertion.
The origin is the fixed point while the insertion is the place that is moved during a muscle
contraction.
All skeletal muscles have an origin, insertion, and action. The origin is the bony site of
attachment which is stationary during the movement. The insertion of a muscle is the
bony site of attachment that is moved by the muscle contraction. (see Figure 5.3)
The origin and insertion can be reversed in different types of movement. For this
module, the standard origin and insertion points are referenced from anatomical
position.
The action of the muscle is what effect is produced by the muscle’s contraction. For
example, the triceps is the primary extensor of the forearm. The innervation is the
peripheral nerve that supplies a muscle with the message from the brain. For example,
the innervation of the biceps brachii is the musculocutaneous nerve. (see Figure 5.4)
, Figure 5.4 Anterior view of the musculocutaneous nerve (blue) innervates the biceps brachii muscle.
Muscles are generally studied in groups. The following muscle list is an overview of
some of the major muscles in the body. Study the location of the muscle in the body.
In addition, if listed, study the origin, insertion, innervation and action of these
muscles.
Muscles of Facial Expression: (See Figure 5.5)
The muscles in this grouping help to facilitate all the actions within the face. All the
varied facial expressions are enabled by these muscles. CN is an abbreviation for
cranial nerve. There are twelve pairs of cranial nerves that originate on the ventral
surface of the brain, controlling muscles and functions of several organs and glands.
Orbicularis oculi
Action: eye closure
Innervation: Facial nerve (CN VII)
Orbicularis oris
Action: mouth closure: closes lips, protrudes lips forward, presses lips against teeth
