1. Chapter 10—The Muscular System

2. I. Introduction & connective tissues of a muscle

3. § Introduction of Muscles
600 Human skeletal muscles
The study of muscles– Myology

4. § The Functions of Muscles
Movement of body parts and body contents– Examples
Maintain posture and prevent unwanted movement— resist the gravity etc.
Communication – Nerves communicate with the brain to move body
Control of openings and passageways– Examples-- eyelids, sphincters, mouth
Heat production– 85% of our body heat is from skeletal muscle contraction

5. § Connective Tissues of a Muscle
5. Tendon
4. Deep fascia
3. Epimysium
2. Perimysium
Muscle fascicle
1. Endomysium
Muscle fiber

6. Connective Tissues of a Muscle
Endomysium
thin areolar tissue around each muscle fiber
allows room for blood vessels and nerves
Perimysium
slightly thicker layer of connective tissue
surrounds bundle of cells called a fascicle
Epimysium
covers whole muscle belly
blends into CT sheets called fascia (next slide)

7. Location of Fascia Deep Fascia Femur Skin Deep fascia
found between adjacent muscles; no fat
Superficial fascia (adipose tissue; hypodermis)
between skin and muscles
Superficial Fascia
Deep Fascia
Femur
Skin

8. § Ways of Muscle Attachments
To bone directly--
epimysium is continuous with periosteum of a bone
Ex.– intercostal muscles
To bone indirectly--
epimysium continues as tendon that merges into periosteum
Ex.-- many including biceps brachii to scapula
To fascia or tendon of another muscle--
To collagen fibers (dermis)--
Ex.--muscles for facial expression
To a broad sheetlike tendon, aponeurosis--
Ex.--certain abdominal muscles (Fig )

10. II. General anatomy of skeletal muscles and classification of muscles

11. § Anatomy of Skeletal Muscles
Origin—
stationary end of a muscle when contracts
Belly--
thicker, middle region of muscle
Insertion—
mobile end of muscle
Detail fig. next slide
Biceps brachii

13. § Muscle types based on fascicle direction-1

14. Skeletal Muscle types —based on fascicle direction-2
Fusiform muscles
Features:
biceps brachii m., gastrocnemius of the calf
Parallel muscles; long, uniform width, having parallel fascicles
rectus abdominis m., sartorius of the thigh, zygomaticus major
Convergent muscle; fan-shaped, broad at origin and tapering to a narrower insertion
pectoralis major of the chest
Fig

16. Skeletal Muscle type—based on fascicle direction-3
Pennate muscles (feather-shaped)
fascicles insert obliquely on a tendon, like the shaft of the feather
Unipennate—fascicles approach the tendon from one side; palmar interosseus (hand) (Fig.)
Bipennate—fascicles approach the tendon from both sides; rectus femoris (thigh) (Fig.)
Multipennate--like feathers with their quills on a single point; deltoid (shoulder) (Fig.)
Circular muscles (sphincters)
Features:
orbicularis oculi (eyelids), orbicularis oris, urethral and anal sphincters
10-16

17. Figure 10.29c

18. Fig a

19. Fig a

20. III. Action of muscle groups and muscle innervation

21. § 4 categories of muscles based on actions
Action— movement produced by a muscle
Prime mover or agonist
produces . . .
Example: in flexing the elbow, the prime mover is the brachialis
Synergist aids the prime mover
May stabilize the nearby joint
Or modify the direction of movement
Example: works with brachialis, biceps brachii as a synergist to flex the elbow
* In some textbooks 1 and 2 are opposite.

22. § 4 categories of muscles based on actions
Antagonist is a muscle that . . .
opposes the _____________
Moderates the speed or range of the agonist; preventing excessive movement and injury
Example: Triceps brachii
Fixator is a muscle that . . .
prevents _______________
Elbow flexion– the rhomboids holds the scapula in place (Fig )
10-22

24. In-class activity Question--Muscle Actions during Elbow Flexion
ID which specific muscle of the upper arm is responsible for the above action. (based on the text)
Prime mover (agonist) = ?
Synergist = ?
Antagonist = ?
Fixator = ?

25. § Skeletal Muscle Innervation
Cranial nerves arising from the brain
exit the skull through foramina
numbered I to XII (Fig )
Innervate muscles of the ______________
Spinal nerves arising from the spinal cord
Muscles elsewhere are supplied by these nerves
From spinal cord and exit the vertebral column through intervertebral foramina (Fig. 13.1, 8.23b)

27. Oh Olfactory (I)
Once Optic (II)
One Oculomotor (III)
Takes Trochlear (IV)
The Trigeminal (V)
Anatomy Abducens (VI)
Final Facial (VII)
Very Vestibulocochlear (VIII)
Good Glossopharyngeal (IX)
Vacations Vagus (X)
Are Accessory (XI)
Heavenly Hypoglossal (XII)

28. Figure 13.1b; posterior view

29. Figure 8.23b

30. § How Muscles are Named Terminologia Anatomica
system of Latin names developed in 1895
updated since then
English names for muscles are slight modifications of the Latin names.
Table 10.1 = terms used to name muscles; Examples:
Major = large (Criteria: ____); pectoralis major
Deltoid = triangular (Criteria: _____); Deltoid
Quadriceps = having 4 heads; quadriceps femoris etc.

31. § Learning Strategy (start with Fig. 10.4a and b)
Explore the location, origin, insertion and innervation of 160 skeletal muscles
use tabular information in this chapter.
Increase your retention
examining models and atlases
palpating yourself (atlas B)
observe an articulated skeleton
say the names aloud and check your pronunciation

32. Quadriceps femoris