Bell RingerBell RingerNumber crunch:

There are _____ pairs of ribs

There are _____ bones in the skull

There are _____ vertebrae

There are _____ bones in the human body

LESSON #3LESSON #3SKELETAL SYSTEMSKELETAL 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

• 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.

Functions of Bones

Four Types of Bones

1. 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.

• Short BonesShort bones are short, cube-shaped, and found in the wrists and ankles

Four Types of Bones

• Flat BonesFlat 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 BonesIrregular 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.

Four Types of Bones

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…

1. Homework is due at the beginning of next class

for full credit

2. The test is NEXT CLASS

3. You must bring your ownpencil to the test or you

will lose points

4. DON’T FORGET TO STUDY!!!