Chapter 11
The skeletal system helps support the body, protect soft body parts, produces blood cells, stores mineral and fat. It also permits flexible body movement. Compact bones are really organized and have tubular units called osteons. Bone cells called osteocytes are tiny chambers. The matrix fills the space between. Spongy bones are very different from compact bones; spongy bones are lighter but are designed for strength. Spaces between the spongy bones are filled with red bone marrow. Red bone marrow is a special kind of tissue that produces all different types of blood cells. Cartilage isn’t as strong as bones but it is a lot more flexible. It has no nerves, which is why it’s great for padding joints where stress movement are harder.
Three different types of cartilage: Hyaline, which is firm and kind of flexible. Fibeocartilage is stronger than hyaline cartilage because the matrix contains wide rows of thick, collagen fibers. Elastic cartilage is more flexible than hyaline cartilage because the matrix contains mostly elastic fiber.
There are many different types of cells that are involved in bone growth, remodeling and repairing. Osteoblasts are bone forming cells. They secrete organic matrix of bone and promote the deposition of calcium salts into the matrix. Osteocytes are mature bone cells formed from osteoblasts and they maintain the structure of bone.
Hormones have a major involvement in bone growth. A hormone is a chemical messenger, produced by one part of the body that acts on a different part of the body. Vitamin D is converted to a hormone that acts on the intestinal tract and it’s chief function is intestinal absorption of calcium. Growth hormone stimulates bone growth, however it will be somewhat ineffective if the metabolic activity of cells in not promoted. Particularly the thyroid hormone promotes the metabolic activity of cells. Due to an increased level of sex hormones, adolescents usually experience a dramatic increase in height. This is called the growth spurt.
Bones repairing after they break or fracture is very important and takes place over several months. Here are the four steps.
Hematoma: which is a mass of clotted blood. Blood escapes from ruptured blood vessels after the fracture and forms a hematoma in the space between the broken bones. This happens within 6-8 hours after the fracture.
Fibrocartilaginous callus: Tissue repair begins and the fibro cartilaginous fills the space between the ends of the bone. This goes on for about three weeks after the bone is broken.
Bony callus: spongy bone is converting to fibro cartilage callus to a bony callus. This then joins the broken bones together and lasts about three to four months.
Remodeling: Osteoblasts build new compact bone and osteoclasts absorb the spongy bone.
Bones of the skeleton are classified where they occur in the axial or appendicular skeleton. The axial skeleton consists of the skull, hyoid bone, vertebral column and rib cage. The axial skeleton lies in the midline of the body. The appendicular skeleton is portion forming the pectoral girdles and upper extremities and the pelvic girdle and lower extremities. Included in the appendicular skeleton bones are the shoulder, hip, arm, left and right pectoral girdles.
The skull is formed by brain case and facial bones.
Hyoid bones are attached to the temporal bones by muscles and ligaments.
The Vertebral column has 4 curvatures that aid in more resilience and strength for the upright position.
The rib cage contains the thoracic vertebral, the rib and their associated cartilages and sternum.
In the appendicular it holds pectoral and pelvic girdles and their limbs. These are bones from the shoulder and the hip.
Chapter 12
The different types of muscles that are in the muscular system are smooth muscles, cardiac muscles and skeletal muscles.
Smooth has a single nucleus or the cells are arranged in parallel lines. These muscles are located in the walls of hollow internal organs that make its wall contract.
Cardiac muscles form a wall around the heart. The fibers in it allow it to interlock at the intercalated disks.
Skeletal muscles have fibers that are tubular. These make the skeletal muscles attach to the skeleton. These muscles can be very long and run the length of the muscles.
The functions of the skeleton muscles:
Skeletal muscles support the body, make bones move, help maintain a constant body temperature, contraction assists movement in cardiovascular and lymphatic vessels and help protect internal organs and stabilize joints.
We have different types of muscles for different types of exercise. For those different activities we have muscles known as fast and slow twitch muscles. Fast twitch muscles are most helpful in sports such as sprinting, weight lifting, swinging a golf club, or throwing a shot. Fast twitch muscles are much lighter then slow twitch muscles because they lack mitochondria; they also have little or no myoglobin and have fewer blood vessels than slow twitch.
Slow twitch muscles are mostly used in sports such as long distance running, biking, jogging and swimming. These muscles tire only when they run out of energy. The reason they are so much darker then fast twitch is because they have manly mitochondria.
The skeletal system helps support the body, protect soft body parts, produces blood cells, stores mineral and fat. It also permits flexible body movement. Compact bones are really organized and have tubular units called osteons. Bone cells called osteocytes are tiny chambers. The matrix fills the space between. Spongy bones are very different from compact bones; spongy bones are lighter but are designed for strength. Spaces between the spongy bones are filled with red bone marrow. Red bone marrow is a special kind of tissue that produces all different types of blood cells. Cartilage isn’t as strong as bones but it is a lot more flexible. It has no nerves, which is why it’s great for padding joints where stress movement are harder.
Three different types of cartilage: Hyaline, which is firm and kind of flexible. Fibeocartilage is stronger than hyaline cartilage because the matrix contains wide rows of thick, collagen fibers. Elastic cartilage is more flexible than hyaline cartilage because the matrix contains mostly elastic fiber.
There are many different types of cells that are involved in bone growth, remodeling and repairing. Osteoblasts are bone forming cells. They secrete organic matrix of bone and promote the deposition of calcium salts into the matrix. Osteocytes are mature bone cells formed from osteoblasts and they maintain the structure of bone.
Hormones have a major involvement in bone growth. A hormone is a chemical messenger, produced by one part of the body that acts on a different part of the body. Vitamin D is converted to a hormone that acts on the intestinal tract and it’s chief function is intestinal absorption of calcium. Growth hormone stimulates bone growth, however it will be somewhat ineffective if the metabolic activity of cells in not promoted. Particularly the thyroid hormone promotes the metabolic activity of cells. Due to an increased level of sex hormones, adolescents usually experience a dramatic increase in height. This is called the growth spurt.
Bones repairing after they break or fracture is very important and takes place over several months. Here are the four steps.
Hematoma: which is a mass of clotted blood. Blood escapes from ruptured blood vessels after the fracture and forms a hematoma in the space between the broken bones. This happens within 6-8 hours after the fracture.
Fibrocartilaginous callus: Tissue repair begins and the fibro cartilaginous fills the space between the ends of the bone. This goes on for about three weeks after the bone is broken.
Bony callus: spongy bone is converting to fibro cartilage callus to a bony callus. This then joins the broken bones together and lasts about three to four months.
Remodeling: Osteoblasts build new compact bone and osteoclasts absorb the spongy bone.
Bones of the skeleton are classified where they occur in the axial or appendicular skeleton. The axial skeleton consists of the skull, hyoid bone, vertebral column and rib cage. The axial skeleton lies in the midline of the body. The appendicular skeleton is portion forming the pectoral girdles and upper extremities and the pelvic girdle and lower extremities. Included in the appendicular skeleton bones are the shoulder, hip, arm, left and right pectoral girdles.
The skull is formed by brain case and facial bones.
Hyoid bones are attached to the temporal bones by muscles and ligaments.
The Vertebral column has 4 curvatures that aid in more resilience and strength for the upright position.
The rib cage contains the thoracic vertebral, the rib and their associated cartilages and sternum.
In the appendicular it holds pectoral and pelvic girdles and their limbs. These are bones from the shoulder and the hip.
Chapter 12
The different types of muscles that are in the muscular system are smooth muscles, cardiac muscles and skeletal muscles.
Smooth has a single nucleus or the cells are arranged in parallel lines. These muscles are located in the walls of hollow internal organs that make its wall contract.
Cardiac muscles form a wall around the heart. The fibers in it allow it to interlock at the intercalated disks.
Skeletal muscles have fibers that are tubular. These make the skeletal muscles attach to the skeleton. These muscles can be very long and run the length of the muscles.
The functions of the skeleton muscles:
Skeletal muscles support the body, make bones move, help maintain a constant body temperature, contraction assists movement in cardiovascular and lymphatic vessels and help protect internal organs and stabilize joints.
We have different types of muscles for different types of exercise. For those different activities we have muscles known as fast and slow twitch muscles. Fast twitch muscles are most helpful in sports such as sprinting, weight lifting, swinging a golf club, or throwing a shot. Fast twitch muscles are much lighter then slow twitch muscles because they lack mitochondria; they also have little or no myoglobin and have fewer blood vessels than slow twitch.
Slow twitch muscles are mostly used in sports such as long distance running, biking, jogging and swimming. These muscles tire only when they run out of energy. The reason they are so much darker then fast twitch is because they have manly mitochondria.
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