1. The Muscular System

2. How many muscles do you have in the body?
Approximately 640 muscles!
Muscles make up
approximately 40% of your
body weight

3. Types of Muscles
Voluntary muscles – muscles you can control by will or thinking
What is an example?
Involuntary muscles – muscles you cannot
control at will, but work automatically

4. Different Kinds of Muscles
Skeletal muscle (voluntary)
Smooth (involuntary)
Cardiac (involuntary)

5. Skeletal Striated muscles Holds the skeleton together
Gives the body shape
Helps with everyday movements

6. Smooth Controlled by nervous system automatically
Examples of smooth muscles are the walls of the stomach and intestines, which help break up food and move it through the digestive system.
Smooth muscle is also found in the walls of blood vessels, where it squeezes the stream of blood flowing through the vessels to help maintain blood pressure

7. Cardiac Found in the heart
The walls of the heart's chambers are composed almost entirely of muscle fibers.
Its rhythmic, powerful contractions force blood out of the heart as it beats.

8. How does movement occur?
The motor cortex sends an electrical signal through the spinal cord and peripheral nerves to the muscles, causing them to contract
The motor cortex on the right side of the brain controls the muscles on the left side of the body and vice versa

9. The cerebellum coordinates the muscle movements ordered by the motor cortex

10. Movement continued
Sensors in the muscles and joints send messages back through peripheral nerves to tell the cerebellum and other parts of the brain where and how the arm or leg is moving and what position it's in
Muscles move body parts by contracting and then relaxing. Your muscles can pull bones, but they can't push them back to their original position.
They work in pairs of flexors and extensors

11. What is the longest muscle?
Sartorius
(Quadricep muscle)

12. What is the smallest muscle?
Stapedius
(Inside the ear)

13. What is the widest muscle?
External oblique
(Runs around the side of the upper body)

14. What is the biggest muscle?
Gluteus maximus
(In your buttock)

15. Sternocleidomastoid Location: Side of the neck
Function: Pulls head back and rotates head

16. Pectoralis Major
Location: Chest
Function: Brings arms toward chest

17. Trapezius Location: Upper back and neck
Function: Moves shoulders up and down
Notes: Shrugs shoulders

18. Deltoid Location: Surrounds the shoulder joint
Function: Lifts arm away from body

19. Biceps Location: Front of the upper arm
Function: Pulls lower arm up (flexion)

20. Triceps Location: Back of upper arm
Function: Pulls lower arm down (extension)
Notes: extends arm back

21. Latissimus Dorsi Location: Down the spine and across the back
Function: Pulls arm toward the back

22. External Oblique Location: Outside part of trunk
Function: Trunk rotation

23. Rectus Abdominus Location: Center of stomach
Function: Stabilize the trunk area

24. Gluteus Medius
Location: Hip area
Function: Lift leg out to the side

25. Gluteus Maximus Location: Buttocks Function: Straightens hip
Notes: Sitting to standing

26. Sartorius Location: Inner side of upper thigh
Function: Pulls leg inward

27. Rectus Femoris Location: Front center thigh
Function: Straightens knee and bends hip

28. Vastus Lateralis Location: Front outside part of thigh
Function: Straightens knee

29. Vastus Medialis Location: Front inner part of thigh
Function: Straightens knee

30. Biceps Femoris Location: Back outside thigh
Function: Bends knee and straightens hip

31. Semitendonosus Location: Back inside thigh
Function: Bends knee and straightens hip

32. Gastrocnemius Location: Outside lower back of leg
Function: Raises heel

33. Soleus
Location: Inside back of lower leg
Function: Raises heel

34. Tibialis Anterior
Location: Front of lower leg
Function: Pulls toes up