Bell Ringer Number crunch: There are _____ pairs of ribs There are _____ bones in the skull There are _____ vertebrae There are _____ bones in the human body

LESSON #3 SKELETAL SYSTEM

Functions of Bones Support – provides a hard framework that supports the body an cradles its soft organs Protection – Examples: skull protects brain; vertebrae protects spinal cord

Functions of Bones Movement Bodily movement is carried out by the interaction of the muscular and skeletal systems. For this reason, they are often grouped together as the musculo-skeletal system. Muscles are connected to bones by tendons. Bones are connected to each other by ligaments. Where bones meet one another is typically called a joint. Muscles which cause movement of a joint are connected to two different bones and contract to pull them together. An example would be the contraction of the biceps and a relaxation of the triceps. This produces a bend at the elbow. The contraction of the triceps and relaxation of the biceps produces the effect of straightening the arm.

Functions of Bones Mineral Storage – Bones serve as a reservoir for minerals, the most important of which are calcium and phosphate. These minerals can be released into the bloodstream for the rest of the body. *Blood cells are produced by the marrow located in some bones. An average of 2.6 million red blood cells are produced each second by the bone marrow to replace those worn out and destroyed by the liver.* Blood cell formation – occurs within the marrow cavities of certain bones.

Four Types of Bones Long Bones Long bones are longer than they are wide and work as levers. The bones of the upper and lower extremities (ex. humerus, tibia, femur, ulna, metacarpals, etc.) are of this type.

Four Types of Bones Short Bones Short bones are short, cube-shaped, and found in the wrists and ankles

Four Types of Bones Flat Bones Flat bones have broad surfaces for protection of organs and attachment of muscles (ex. ribs, cranial bones, bones of shoulder girdle).

Four Types of Bones Irregular Bones Irregular bones are all others that do not fall into the previous categories. They have varied shapes, sizes, and surfaces features and include the bones of the vertebrae and a few in the skull.

Is there a difference between the male and female skeletons? ANSWER: Yes, female skeletons are wider across the pelvis and male skeletons are wider across the top of the shoulders.

What is a joint? When a bone meets another bone and there is movement.

What is the purpose of cartilage? The purpose of cartilage is to cushion bones. Cartilage is found at the ends of bones.

Tendons and Ligaments Tendons & Ligaments Attachment Muscle/Bone Attachment Bone/Bone

Answer to Bell Ringer: Number crunch: There are 12 pairs of ribs There are 22 bones in the skull There are 33 vertebrae There are 206 bones in the human body

REMEMBER… Homework is due at the beginning of next class for full credit The test is NEXT CLASS You must bring your own pencil to the test or you will lose points DON’T FORGET TO STUDY!!!