1. Muscles and Muscle Tissue
LAB 10

2. Muscle Overview Muscle tissue makes up nearly half the body mass.
The most distinguishing functional characteristic of muscles is their ability to transform chemical energy ATP into directed mechanical energy
The three types of muscle tissue are: skeletal, cardiac, and smooth
These types differ in structure, location, function, and means of activation

3. MARTINI
PG 133

4. Muscle Similarities
Skeletal and smooth muscle cells are elongated and are called muscle fibers
Muscle contraction depends on two kinds of myofilaments – actin and myosin
Muscle terminology is similar
Sarcolemma – muscle plasma membrane
Sarcoplasm – cytoplasm of a muscle cell
Prefixes – myo, mys, and sarco all refer to muscle

5. Functional Characteristics of Muscle Tissue
Excitability, or irritability – the ability to receive and respond to stimuli
Contractility – the ability to shorten forcibly
Extensibility – the ability to be stretched or extended
Elasticity – the ability to recoil and resume the original resting length

6. Muscle Function Skeletal muscles are responsible for all locomotion
Cardiac muscle is responsible for coursing the blood through the body
Smooth muscle helps maintain blood pressure, and squeezes or propels substances (i.e., food, feces) through organs
Muscles also maintain posture, stabilize joints, and generate heat

7. Muscle Classification: Functional Groups
Prime movers – provide the major force for producing a specific movement
Antagonists – oppose or reverse a particular movement
Synergists
Add force to a movement
Help stabilize the joint movement
Fixators – synergists that immobilize a bone or muscle’s origin

8. Naming Skeletal Muscles
Location of muscle – bone or body region associated with the muscle
Shape of muscle – e.g., the deltoid muscle (deltoid = triangle)
Relative size – e.g., maximus (largest), minimus (smallest), longus (long)
Direction of fibers – e.g., rectus (fibers run straight), transversus, and oblique (fibers run at angles to an imaginary defined axis)

9. Naming Skeletal Muscles
Number of origins – e.g., biceps (two origins) and triceps (three origins)
Location of attachments – named according to point of origin or insertion
Action – e.g., flexor or extensor, as in the names of muscles that flex or extend, respectively

10. Major Skeletal Muscles: Posterior View
The 27 superficial muscles here are divided into seven regional areas of the body:
1.- Neck
2.- Shoulder
3.-Arm
4.- Forearm
5.- Hip
6.-Thigh
7.- Leg
Figure 10.5b

11. Muscles of the Face
11 muscles are involved in lifting the eyebrows, flaring the nostrils, opening and closing the eyes and mouth, and smiling
All are innervated by cranial nerve VII (facial nerve)
Usually insert in skin (rather than bone), and adjacent muscles often fuse

12. Muscles of the Face
Figure 10.6

13. Muscles of Mastication
There are four pairs of muscles involved in mastication
Prime movers – temporalis and masseter
Grinding movements – pterygoids and buccinators
All are innervated by cranial nerve V (trigeminal nerve)

14. Muscles of Mastication
Figure 10.7a

15. Muscles of Mastication
Figure 10.7b

16. Extrinsic Tongue Muscles
Three major muscles that anchor and move the tongue
All are innervated by cranial nerve XII (hypoglossal nerve)

17. Extrinsic Tongue Muscles
Figure 10.7c

18. Thorax and neck slides