Muscular & Skeletal Systems

1. Muscular & Skeletal Systems

2. Muscular System • Muscles are the motors that move body parts. • Bones and joints have no power to move on their own. • More than 600 muscles in the body • 35–40% of body mass ismuscle

3. Muscular System • Muscle—organ that contracts and becomes shorter orexpandsandbecomeslonger • Result = Body parts move, energy is used, and work is done.

4. Muscular System • Two Groups of Muscles • Voluntary—You can control these. • Arms, legs, hands, face 2. Involuntary—You can’t control these; you don’t have to decide to make these muscles work. • Muscles around the heart

5. Muscular System • Three Types of MuscleTissue 1. Skeletal Muscle • Most numerous in body • Looks striped (striated) • Attached to the bones by tendons • Tendons—thick bands that pull on the bone as the muscle contracts • Voluntary • Contract quickly, tire easily

6. Muscular System • Three Types of MuscleTissue (cont.) 2. Smooth Muscle • Involuntary • Found in: walls of stomach, intestine, uterus, etc. • Contracts and relaxes slowly • No striations

7. Muscular System • Three Types of MuscleTissue (cont.) 3. Cardiac Muscle • Only found in heart • Involuntary • Has striations • Contracts 70 times per minute (heartbeat)

8. Muscles at Work • Skeletal muscle movements are results of pairs of muscles working together. • One musclecontractswhile the other musclerelaxes. • Muscles alwayspull; theynever push.

9. Muscles at Work • Results of Muscle Action • Muscles contract • This producesthermalenergy, and it uses chemical energy. • Thermal energy produces heat that helps keep body temperature constant. • Chemical energy is from glucose. (When glucose is used up, muscles are tired and need to rest.)

10. Muscles at Work • Resultsof Muscle action (cont.) • Over time, muscles become larger or smaller, depending on how much work they do.

11. Skeletal System • Made up of all of the bones in your body, it is the framework of the body. • Each bone in your body is a livingorgan, made of differenttissues. • Cells in bones take in food and use energy.

12. Skeletal System • Made up of all of the bones in your body, it is the framework of the body. - Five Functions of Skeletal System 1. Framework gives shape & support to the body.

13. Skeletal System • Made up of all of the bones in your body, it is the framework of the body. • Five Functions of Skeletal System 1. Framework gives shape and support to the body. 2. Bones protect the internal organs.

14. Skeletal System • Made up of all of the bones in your body, it is the framework of the body. • Five Functions of Skeletal System 1. Framework gives shape & support to the body. 2. Bones protect the internal organs. 3. Major muscles of the body are attached to the bones.

15. Skeletal System • Made up of all of the bones in your body, it is the framework of the body. • Five Functions of Skeletal System 1. Framework gives shape & support to the body. 2. Bones protect the internal organs. 3. Major muscles of the body are attached to the bones. 4. Blood cells are formed in red marrow of some bones.

16. Skeletal System • Made up of all of the bones in your body, it is the framework of the body. • Five Functions of Skeletal System 1. Framework gives shape & support to the body. 2. Bones protect the internal organs. 3. Major muscles of the body are attached to the bones. 4. Blood cells are formed in red marrow of some bones. 5. Skeleton is a place where major quantities of calcium and phosphorus compounds are stored.

17. Bones • Theadult skeleton has 206 bones (baby has 270).

18. Joints • Any place where two or more bones meet • Ligaments: tough bands of tissue that hold bones together at the joints