Bones are made up of two types of tissue: compact bone and spongy bone. Compact bone is the hard, outer layer of the bone, while spongy bone is the inner, porous layer. Within the bone, there is also bone marrow, which is responsible for producing bloodcells.
Functions of Bones
Bones serve several important functions in the body:
Support: Bones provide a framework for the body, allowing us to stand, sit, and move.
There are five main types of bones in the human body:
Long bones: Found in the arms, legs, fingers, and toes. They are longer than they are wide and are responsible for supporting weight and facilitating movement.
Short bones: Found in the wrists and ankles. They provide stability and support in the body.
Flat bones: Found in the skull, ribs, and shoulder blades. They provide protection for internal organs and offer a broad surface for muscle attachment.
Irregular bones: Found in the spine and hips. They have complex shapes and provide support and protection.
Sesamoid bones: These are small, round bones found embedded in tendons. The patella (kneecap) is the largest sesamoid bone in the body.
Common Bone Disorders
There are several common disorders that can affect the skeletal system:
Osteoporosis: A condition characterized by weak, brittle bones that are more prone to fractures.
Osteoarthritis: A degenerative joint disease that can affect the joints in the body, including those in the spine, hands, hips, and knees.
Rickets: A condition that affects bone development in children, often due to a deficiency in vitamin D, calcium, or phosphate.
Now that we've covered the basics of bones, here are some study questions to test your understanding:
What are the two types of tissue that make up bones?
What is the function of bone marrow?
Which type of bone is responsible for supporting weight and facilitating movement?
Use evidence and scientific reasoning to explain how characteristic animal behaviors (e.g., building nests to protect young from cold, herding to protect young from predators, attracting mates for breeding by producing special sounds and displaying colorful plumage, transferring pollen or seeds to create conditions for seed germination and growth) and specialized plant structures (e.g., flower brightness, nectar, and odor attracting birds that transfer pollen; hard outer shells on seeds providing protection prior to germination) affect the probability of successful reproduction of both animals and plants.