Bones and Muscles Study Guide

The body has cells, tissues, and organs.

  • The cell is a basic unit of life, and the human body has many specialized cells that perform functions. A tissue is a group of cells that function together.
  • Types of tissues:
  • Epithelial-forms boundaries
  • Muscle-allows for movement
  • Nerve-carries messages
  • Connective-supports, protects, pads, insulates, and stores energy
  • Organs- two or more types of tissues that work together to perform a function. These organs can work together in an organ system.

The Body’s Systems interact with one another.

  • All of these systems work together to reach an internal balance called homeostasis. Example: Maintaining body temperature

Bones are living tissues.

  • The skeletal system is composed of bone tissue. Bones are mainly calcium.
  • Compact bone: dense tissue that gives bone strength
  • Spongy bone: strong and lightweight
  • Marrow: takes up space in the spongy bone and produces red blood cells
  • Blood vessels: supply oxygen and nutrients to bone and carries away new blood cells
  • The skeleton has two main divisions.
  • Axial Skeleton- runs top to bottom it contains the skull, vertebrae, and ribs.
  • Appendicular Skeleton- runs side to side it contains the bones of the shoulder, arms, hips, and legs.
  • The skeleton changes as the body develops and grows.
  • As an infant the skeleton allows for rapid growth and development. The skeleton has an opening in the head at birth. The skull grows together as the baby ages. The bones of the arms and legs have long bones which have growth plates at their ends. The plates allow bones to grow longer until puberty. Bones are constantly being broken down and replaced, but older adults see the replacement not keeping up with loss. Bone density may decrease as you age.

Joints Connect parts of the skeletal system

  • Immovable joints lock bones together at places called sutures. The skull has immovable joints.
  • Tissues called ligaments hold bones together at freely movable joints.

The muscular system makes movement possible

  • Muscles move the body.
  • Muscles help maintain the body’s temperature by generating heat.
  • Muscles maintain upright posture.

There are three types of muscle.

  • Skeletal or voluntary muscles- allow the body to move when you want it to
  • Smooth or involuntary- found inside organs and allow the body perform automatic movements
  • Cardiac-heart muscle. Its cells are arranged in webs that contract without conscious control

Skeletal muscles and tendons allow bones to move

  • Tendons attach muscles to bone.
  • One Muscle contracts, pulling the bone while the other lengthens.