Skeletal System Physiology
Dieting Eating Healthy eating pyramid Nutritional rating systems Lists: The third iron-containing pigments, the hemerythrins , are violet. The FNP has developed a series of tools to help families participating in the Food Stamp Program stretch their food dollar and form healthful eating habits including nutrition education. Many tiny cells called osteocytes live in small spaces in the matrix and help to maintain the strength and integrity of the compact bone. Simple carbohydrates may be single sugar molecules called monosaccharides or two monosaccharides joined together called disaccharides. The second most abundant mineral in the human body, it is found in practically every cell.
The lower arm bones form the wrist joint with the carpals, a group of eight small bones that give added flexibility to the wrist. The carpals are connected to the five metacarpals that form the bones of the hand and connect to each of the fingers.
Each finger has three bones known as phalanges, except for the thumb, which only has two phalanges. Formed by the left and right hip bones, the pelvic girdle connects the lower limb leg bones to the axial skeleton. The femur is the largest bone in the body and the only bone of the thigh femoral region. The femur forms the ball and socket hip joint with the hip bone and forms the knee joint with the tibia and patella.
Commonly called the kneecap, the patella is special because it is one of the few bones that are not present at birth. The patella forms in early childhood to support the knee for walking and crawling. The tibia and fibula are the bones of the lower leg. The fibula is mainly a muscle attachment point and is used to help maintain balance. The tibia and fibula form the ankle joint with the talus, one of the seven tarsal bones in the foot. The tarsals are a group of seven small bones that form the posterior end of the foot and heel.
The tarsals form joints with the five long metatarsals of the foot. Then each of the metatarsals forms a joint with one of the set of phalanges in the toes. Each toe has three phalanges, except for the big toe, which only has two phalanges. Living bone cells are found on the edges of bones and in small cavities inside of the bone matrix. Although these cells make up very little of the total bone mass, they have several very important roles in the functions of the skeletal system.
The bone cells allow bones to:. All of the bones of the body can be broken down into five types: The long bones of the body contain many distinct regions due to the way in which they develop. At birth, each long bone is made of three individual bones separated by hyaline cartilage.
The epiphyses and diaphysis grow towards one another and eventually fuse into one bone. Once the long bone parts have fused together, the only hyaline cartilage left in the bone is found as articular cartilage on the ends of the bone that form joints with other bones.
The articular cartilage acts as a shock absorber and gliding surface between the bones to facilitate movement at the joint. Looking at a bone in cross section, there are several distinct layered regions that make up a bone. The outside of a bone is covered in a thin layer of dense irregular connective tissue called the periosteum.
The periosteum contains many strong collagen fibers that are used to firmly anchor tendons and muscles to the bone for movement. Stem cells and osteoblast cells in the periosteum are involved in the growth and repair of the outside of the bone due to stress and injury.
Blood vessels present in the periosteum provide energy to the cells on the surface of the bone and penetrate into the bone itself to nourish the cells inside of the bone. The periosteum also contains nervous tissue and many nerve endings to give bone its sensitivity to pain when injured. Deep to the periosteum is the compact bone that makes up the hard, mineralized portion of the bone.
Compact bone is made of a matrix of hard mineral salts reinforced with tough collagen fibers. Many tiny cells called osteocytes live in small spaces in the matrix and help to maintain the strength and integrity of the compact bone. Deep to the compact bone layer is a region of spongy bone where the bone tissue grows in thin columns called trabeculae with spaces for red bone marrow in between. The trabeculae grow in a specific pattern to resist outside stresses with the least amount of mass possible, keeping bones light but strong.
Long bones have a spongy bone on their ends but have a hollow medullary cavity in the middle of the diaphysis. The medullary cavity contains red bone marrow during childhood, eventually turning into yellow bone marrow after puberty. An articulation, or joint, is a point of contact between bones, between a bone and cartilage, or between a bone and a tooth. Synovial joints are the most common type of articulation and feature a small gap between the bones.
This gap allows a free range of motion and space for synovial fluid to lubricate the joint. Fibrous joints exist where bones are very tightly joined and offer little to no movement between the bones.
Fibrous joints also hold teeth in their bony sockets. Finally, cartilaginous joints are formed where bone meets cartilage or where there is a layer of cartilage between two bones. These joints provide a small amount of flexibility in the joint due to the gel-like consistency of cartilage. The bones of the axial skeleton act as a hard shell to protect the internal organs—such as the brain and the heart —from damage caused by external forces.
The bones of the appendicular skeleton provide support and flexibility at the joints and anchor the muscles that move the limbs. The bones of the skeletal system act as attachment points for the skeletal muscles of the body. Almost every skeletal muscle works by pulling two or more bones either closer together or further apart. Joints act as pivot points for the movement of the bones. The regions of each bone where muscles attach to the bone grow larger and stronger to support the additional force of the muscle.
In addition, the overall mass and thickness of a bone increase when it is under a lot of stress from lifting weights or supporting body weight. Red bone marrow produces red and white blood cells in a process known as hematopoiesis. Red bone marrow is found in the hollow space inside of bones known as the medullary cavity. The amount of red bone marrow drops off at the end of puberty, replaced by yellow bone marrow.
The skeletal system stores many different types of essential substances to facilitate growth and repair of the body. Proper levels of calcium ions in the blood are essential to the proper function of the nervous and muscular systems. If the sock had the same closure at the toe end, then it could better represent a stomach or a very short bowel. Name Description and Function. Their purpose is to rip, grind, mash and generally pulverize all that food we put into our mouths.
So that it fits down our throats. Swallowing triggers its closing over the trachea to prevent food and fluids from draining into our lungs. Concentrated bile is released into the duodenum as needed to break down fats into an absorbable form. This duct collects donations from the liver and the gall bladder bile as it passes along to the duodenum of the small bowel. There are many sections to the large bowel — the appendix, caecum, ascending rising colon, transverse across colon, descending going down colon, sigmoid colon, the rectum and the anus.
The main purposes of the large intestine is to pass remaining essential nutrients into the bloodstream and the storage and elimination of waste left-overs. As the nutritional fluids are absorbed and transfered out to the bloodstream, the contents get more solid and compact. Sometimes a piece of food gets stuck in here like bubblegum causing an infection.
This fluid enzyme helps to soften up the food, the first chemical action along the digestive trail. It starts at the pyloric sphincter of the stomach and runs about 10 inches. The duodenum is largely responsible for the continuing food breaking-down process fats are bombarded with bile , with the jejunum and ileum mainly responsible for the transfer of nutrients into the bloodstream.
Both insulin and glucagon are produced by the pancreas. The duodenum is responsible for continuing to break down of food into liquid form and the jejunum and ileum mainly responsible for absorption of nutrients into the bloodstream. When the rectum becomes full, it triggers nerves that carry that message to the brain.
Make a Purse-string Sphincter or Valve In the digestive system, there are a number of places along the way that are designed to help regulate when, what direction, and how fast, food travels.