Most the bones in our body are made of the same materials. Each bone has four main layers. The outside of the bone is called the periosteum. This layer contains nerves and blood vessels that bring nutrients to the bone. Next is the compact bone. It is the hardest part of the bone. Inside the compact bone is the cancellous bone. This part of the bone is light and spongy, but still strong. The innermost layer of bone is called the marrow. This layer is almost like a thick jelly. Bone marrow produces red blood cells, which help to bring oxygen to all the different parts of our body, and white blood cells, which our body uses to fight off diseases and infections. Our skeleton also gives our body its shape and allows us to move. The skeleton is our body’s frame; if we did not have bones, we would all flop around like jellyfish. The special way our bones connect enable movement. The places where our bones meet are called joints. These are the parts of your body that you can bend and move, like your knees, elbows, shoulders, and fingers. For an example, look at one of the legs on the diagram of the skeleton. You will see bones called the femur, the tibia, and the fibula. The place where these bones meet is the knee. The knee is a joint; it is protected by the patella bone (also called the kneecap).

Finally, our bones also protect our most important organs. As you might imagine, bones are much harder than the soft, fragile organs inside of our body. For example, the ribs and sternum protect our heart, lungs, and major blood vessels. The skull protects our brain. The vertebrae in our spine protect the nerves in our spinal column. Without our bones, our bodies’ most vital organs would be much more vulnerable.

The next time you see a skeleton while watching a scary movie or visiting a haunted house, remember: those bones may be creepy, but you would not be able to live without them!
According to the passage, all of the following are protected by a bone EXCEPT

A
the stomach

B
major blood vessels

C
the brain

D
the knee joint

What advantage is the cell wall in relationship to osmotic pressure

Prompt: read the following case study and discuss the questions listed at the end of this page. brittany is a 15-year-old freshman in high school. she is the oldest child in a single parent family. she enjoys sports and participates in volleyball, basketball, track, and softball at school. her usual day consists of breakfast at home, which is usually a pop-tart on the way out of the house. lunch is a fast food meal with friends that often consists of a double cheeseburger, fries, and large regular soda pop after which she often feels stuffed and bloated, but feels she needs the calories for her busy sports schedule. she then doesn’t eat again until later in the evening even if she is hungry after school. supper is either a hot dog or pop at ball games or left-over food in the refrigerator after she gets home from practice. she doesn’t care much for fruits and vegetables other than bananas, corn and lettuce salad, as her mom seldom prepares them for the family or keeps fresh fruit on hand. she is 5’6” and weighs 115 pounds and would like to weigh closer to 100–105 pounds. a weight-for-height table puts her weight range at 125 pounds to 135 pounds. she is worried about gaining weight. a cute guy in her math class that she would like to date was overheard talking to his buddies and making fun of large girls in the class. she feels like she is always stressed for time with games and practices, homework to do in the evenings, and household duties she does for her mom who works to support the family. she feels like she has no leisure time for herself. when feeling extra stressed she will eat an entire large bag of potato chips or three to four cups of ice cream and then feel guilty afterward. questions: 1. name some of the components of brittany’s lifestyle and eating patterns that are contrary to the wellness approach to body size and weight management principles covered in this section. 2. what are some improvements she could make based on these principles? name as many as you can. what are some practical ways you can make improvements or healthy things you are already doing?

Which of these example of a hereditary risk factor? smoking, eating junk food everyday, being a couch potato, having fair skin that is prone to sunburn