Skeletal and Muscular System

Tissue A tissue is considered a collection of cells that are similar in structure and work together to perform a certain function. There are different types of tissue: – Muscle Tissue – Nervous Tissue – Epithelial Tissue – Connective Tissue

Muscle Tissue Muscle tissue is composed of cells that can contract. Contraction is their main function. There is three types of muscle tissue: – Skeletal muscle: Moves your bones – Smooth muscle: Movement of bodily functions we don’t consciously control (Example: our bowels) – Cardiac Muscle: Pumps the heart and has cells that can send out an electrical impulse.

Nervous Tissue Nervous Tissue is made up of cells that can send and receive chemical signals. Nervous Tissue is made up of neurons.

Epithelial Tissue Epithelial Tissue is designed as a covering. It’s main function is to protect and give support. It lines your blood vessels, holds up your organs and covers the outside of your body.

Connective Tissue These tissues are meant to connect and support structures. They can be solids, liquid or in between. These tissues include: – Ligament – Tendons – Bone – Cartilage – Fat – Blood

Muscle Cells Each single muscle cell is elongated and is called a fiber. Put the muscle fibers together and you have a fascicles.

Muscle Movement Muscle movement is either voluntary or involuntary. Contractions that can be consciously controlled are called voluntary muscle movements. Contractions that can NOT be consciously controlled are called involuntary muscle movement.

How do the muscles contract With in each muscle fiber there are filaments. There is a set of Myosin filaments which have little hooks and a set of Actin filaments that look like strands of beads. Along the fiber there is a section where Actin filaments attach. This region is called the Sarcomere.

How Do muscles Contract When nerves in the muscle receive a signal to contract it stimulates the muscle. The Myosin use their little hooks to pull the Actin Filaments together.

Force When a single muscle fiber is stimulated is contracts fully. If more force is needed more fibers are activated. More Fibers more force.

Tendons Skeletal Muscles are generally attached directly to the bone. The muscles itself can attach or a tough fibrous cord called a Tendon attaches to the muscle and the bone.

Ligaments/Cartilage Ligaments are also hard connective tissue, but their main purpose is to hold together joints. Cartilage is another sturdy tissue, but in this case it is made to either protect or replace bone.

The skeleton The Skeleton has two main parts, the Axial and the Appendicular. The Axial Skeleton is your skull, ribs, spine, and sternum. Appendicular is the arms, legs and all the bones that join them to the trunk of your body.

Bones The Skeletal system provides protection and support, but bones are not completely solid all the way through. Bones have layers……….just like ogres.

Bone Structure The surface of a bone has a tough membrane that is full of blood vessels and nerves. This outer layer is called the Periosteum.

Bone Structure Under the Periosteum is the hard thick layer called the Compact Bone. This is the part of the bone that gives it its rigidity and strength. It’s made of Proteins and Minerals (calcium)

Bone Structure In between the layers of protein are actual bone cells called Osteocytes.

Bone Structure With in the compact bone are channels. Each Channel carries a blood vein and an artery. These Channels are called Haversian Canals

Bone Structure Beneath the compact bone is the Spongy Bone. You would think it was soft, but it’s not. It’s hard and is another form of support and strength.

Bone Structure With in the Spongy Bone is the Bone Marrow. Bone Marrow is a softer tissue that produces red blood cells, platelets, and white blood cells. This is where new blood cells are made.

Bone Development In the second month of fetal development the skeleton is mostly cartilage. In the third month minerals start to grow in between the cells of the cartilage turning the cartilage to bone. This process is called Ossification.

Bone Growth After you are born (and through out your teenage years) your bones continue to grow. The growth occurs at the end of your long bones in an area called the Epiphyseal Plate (growth plate) The plate produces cartilege cells that push against the shaft of the bone there by elongating it.

Bone Growth. The plate produces cartilage cells that push against the shaft of the bone there by elongating it. The older cartilage cells die off and are replaced by bone.

Class work Write a paragraph describing the largest muscle group on your animal as well as why those muscles are the most developed. After you have written your paragraph go to a lab table and begin the lab.