Unit 3 - Bio 180-271 - Muscular System: Slides 48-118 (Excludes Tables)

Define Muscle Hypertrophy

The enlargement of stimulated muscle

In what (4) ways does muscle hypertrophy affect the muscles?

Increases diameter of muscle fiber

Increases the number of myofibrils

Increases mitochondria number

Increases glycogen reserves

Define Muscle Atrophy

The reduction in muscle size, tone, and power

How can muscle atrophy be prevented/reduced?

Through electrical stimulation, which acts as a replacement for neuronal stimulation (when the body is unable).

How are skeletal muscles classified?

Based on fascicle organization

Name the four classifications of skeletal muscles

1. Parallel muscles

2. Convergent muscles

3. Pennate muscles

4. Circular muscles

Define Parallel Muscles

Muscles that contain muscle fibers that are parallel to the long axis of the muscle;

contains a central, spindle shaped, muscle body;

Tendons at the ends of muscle are moving parallel with one another

Define Convergent Muscles

Broad areas of muscle fiber converge on a tendon, aponeurosis, or raphe

Define Pennate Muscles

Muscles that form an angle with the tendon;

contain more myofibrils and develop more tension than parallel muscles;

Tendons at the ends of the muscle are moving perpendicular

Define Circular Muscles

Sphincter muscles;

Muscles that guard body entrances

Define Origins

The fixed point of attachment of a muscle

Define an Insertion

One moving point of attachment of a muscle

What are the origins and attachments of muscles typically attached to?

Most origins and insertions attach to the skeleton

Where are origins and insertions typically located in relation to one another?

Typically, origins are proximal to insertion

Define Action and name an example

Movement produced by muscle contraction;

ie. flexion, extension, adduction, abduction, etc.

Why do different muscle groups work together?

To maximize efficiency

Which muscles reach tension first: smaller or larger muscles?

Smaller muscles

Define an agonist

The prime mover;

produces a particular movement

Define Antagonist

Opposes movement of a particular agonist

Provide an example of agonist and antagonist

When you contract the biceps brachii, the triceps brachii may oppose the movement

Define Synergist

A smaller muscle that assists a large agonist

Name the two possible roles of a synergist and an example of each

A synergist may...

1. act as a fixator by stabilizing the agonist muscle (ie. deep low back muscles)

2. act as an initiator by starting a movement (ie. brachialis)

What is the platysma known as?

"The shaving muscle"

Name the six extrinsic eye muscles

1. Inferior rectus

2. Medial rectus

3. Superior rectus

4. Lateral rectus

5. Inferior oblique

6. Superior oblique

What are the extrinsic eye muscles collectively responsible for?

The movement of both eyes

True or False: The Levator palpebrae superioris is an extrinsic eye muscle.

False

What is the role of the Trochlea?

The Trochlea "holds onto" the superior oblique.

Define Mastication

The process by which found is ground and crushed up by teeth;

chewing

Name the four muscles of Mastication

1. Masseter muscles (elevates AND closes)

2. Temporalis muscles (elevates)

3. Medial Pterygoid muscles

4. Lateral Pterygoid muscles

Define lateral excursion

Rocking the jaw side to side;

A unique action to the pterygoid muscles

What is the role of the pterygoid muscles in mastication?

To align teeth during mastication by tensing to prevent lateral excursion

How are the muscles of the tongue named?

According to origin and insertion.

What are the muscles of the tongue called?

Extrinsic Tongue Muscles

What does "-glossus" mean?

"Tongue"

What does "-genio" refer to?

The inner portion of the mandible

Name the Pharyngeal constrictor muscles

• Superior constrictor

• Middle constrictor

• Inferior constrictor

Role of the pharyngeal constrictor muscles

move food into the esophagus

Define Laryngeal elevator muscles

Muscles that elevate the larynx (to close the epiglottis)

Name the Palatal muscles

• Levator veli palatini (elevates the soft palate)

• Tensor veli palatini (tenses the soft palate)

Role of the Palatal Muscles

To lift the soft palate

What is the name for the spinal extensor muscles?

Erector Spinae

What is the role of most muscles of the back?

Extension

Name the Superficial Spinal Extensors (agonist) of the back

• Iliocostalis - most lateral

• Longissimus - in the middle

• Spinalis - most medial

Name the Deep Spinal Extensors of the back

• Semispinalis group

• Multifidus muscle

• Interspinalis muscles

• Intertransversarii muscles

• Rotatores muscles

Where are the spinal flexors located?

In the neck (cervical) and lumbar region

Name the Neck Flexor muscles

• Longus capitis

• Longus coli

Name the Lumbar Flexors

Quadratus lumborum

True or False: The external anal sphincter is a muscle

False

True or False: The external anal sphincter is made up of muscle fibers

True

What kind of muscles does the coccyx attach to?

Muscles that have to do with voluntary defecation

Which set of muscles wraps around the ribs?

Serratus Anterior

Name the three major regions of the trapezius

• Upper Trapezius (1)

• Mid-trapezius (2 & 3)

• Lower Trapezius (4)

Which muscles are underneath the Trapezius?

The Rhomboids

Name the four muscles of the Rotator Cuff

• Teres minor

• Subscapularis

• Infraspinatus

• Supraspinatus

Which two rotator cuff muscles work closely together?

The Teres Minor and the Infraspinatus:

Both act as lateral rotators

Role of the Biceps Brachii

Acts as the agonist to flexion at the elbow

How many branches of the facial nerve are there?

Five