1. The Muscular and Skeletal Systems
By: Ezzy & Laura

2. 5 Teaching points
1.There are 5 functions of the skeletal system such as protection, shape, support, movement and blood cell production and storage.
2. The basic structure includes 3 types of cells, osteocytes, osteoclasts, osteoblasts and 4 types of bone tissues.
3. Homeostasis in the Skeletal and Muscular System.
4. There are 3 types of muscle tissue in the muscular system
5. The sliding Filament Theory explains how muscle fiber contracts.

3. Functions of the Skeletal System
1)Protection- of internal organs
2)Shape- the skeletal system determines height, width and other functions. (Hand size, feet size)
3)Movement- allows walking, sitting, standing, and any other movements.
4)Blood cell production- maintains mineral homeostasis.
5)Support-keeps your internal organs in their proper place.

4. Ossification

5. Ossification
Skeleton is made entirely of cartilage, in early development of fetus.
Soft cartilage turns to hard bone through ossification.
Mineral deposits, replace cartilage.
Ossification of long bones,(Ex. Arms & Legs) begin at center of bone continuing toward the end.
Cartilage grows as long bones grow.

6. The Basic Structure of bones includes 3 different types of bone cells and 4 main bone tissues

7. Types of bone cells
• Osteoblasts- make new bone cells by taking up minerals from the blood.
• Osteocytes regulate mineral homeostasis. They direct the uptake of minerals from the blood
• Osteoclasts dissolve minerals in bone matrix and release them back into the blood

8. 4 Main Bone Tissues
Compact bone makes up the dense outer layer of bone. It's hard and strong.
Spongy bone is found inside bones. Is lighter and dense
Bone marrow- connective tissue that produces blood cells. Found inside the pores of spongy bone.
Periosteum- Tough Membrane. Protects the outsides of bone.

9. The 3 types of Muscle Tissues & their functions

10. Muscle Tissues
Skeletal muscle is muscle tissue that is attached to bones. Skeletal muscle is the most common type of muscle in the human body.
Cardiac muscle is found only in the walls of the heart.
Smooth muscle is found in the walls of internal organs such as the stomach and intestines.

11. Sliding Filament Theory

12. The Sliding Filament Theory
The most widely accepted theory explaining how muscle fibers contract.
Myosin filaments use ATP energy to “walk” along the actin filaments with their cross bridges.
This pulls actin filaments closer together.
Movement of actin filaments pull Z lines closer together,shortening the sarcomere.
When all sarcomeres in muscle fiber shorten, fiber contracts.
Muscle fiber either contracts fully or not at all.

13. Homeostasis in the Skeletal & Muscular systems

14. Homeostasis in the muscular system
Homeostasis in the muscular system ensures nutrition.
Homeostasis- Makes sure heart rate and delivery of blood and oxygen from the heart circulates into muscles in the body.
Smooth muscle- maintains blood pressure and cardiac muscle circulates blood.
Without oxygen and blood delivery, the muscles would fail.

15. Homeostasis in the Skeletal System
Maintaining Mineral homeostasis is very important for the human body.
Calcium and other minerals inside the blood are needed so the body can function.
Bones circulate blood, take out minerals and put new minerals back into blood.
This blood is pumped through body by muscles.

16. Vocab: Types of joints
Immovable: a joint that is fixed in place or holds something in place. ex: skull
Partly movable: a joint that moves when you want it to
Movable: a join that moves without thinking. ex: fingers