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Lesson 36 Assignments Biology Muscles and the Skeleton Provide Action and Support Every movement you make or every step you take is controlled by the systems of muscles and skeleton that moves and supports the body. The human boy is a complex and elegant mechanism influenced my many factors. Both muscles and the skeleton are not only good for movement, they also influence crucial functions inside the body and the skeleton provides support in maintaining the body’s shape and it protects internal organs.
There are three different kinds of muscles all with different purposes, functions and locations in the body. They are skeletal muscle, cardiac muscle and smooth muscle. Skeletal muscle is named this because it is attached to and moves the skeleton. It is under the direct and normally voluntary or conscious control of the nervous system. Sometimes skeletal muscles are also called or known as striated (meaning ‘striped) muscle because when viewed under a microscope they are striped. Cardiac muscle is only found in the heart and is the specialized muscle of the heart.
It is spontaneously active and involuntary, which means it initiates its own contractions and is not under conscious control, however nerves and hormones also influence it. Like skeletal muscle, cardiac muscle is also strained. Finally the last type of muscle that we human have in our body is the smooth muscle. Smooth muscle does not have the striations of skeletal and cardiac muscles. Therefore it lines the large blood vessels and most hollow organs, such as the digestive tract and bladder. It produces slow, sustained and involuntary contractions.
Like cardiac muscle, smooth muscle is also normally not under voluntary control. All three of these different muscles are very important to the body. Pumping blood through the circulatory system, moving food through the digestive system and even breathing are some of he essential processes that depend on contraction of these muscles. Muscle cells only perform one kind of activity. They exert force by contracting. All works of muscles needs muscles to alternately contract and lengthen, however the muscles are only active during contraction.
The lengthening that comes after the contraction it therefore passive. This happens when muscles relax and are stretched out by other forces. So a relaxed muscle can be lengthened by contractions of the opposing muscles. An example of this is the elbow. The elbow is a hinge Joint, as well as knees and fingers. This means that they only move in two dimensions. Antagonistic muscle pairs known as the flexed and extensor move the Joint. The elbow joint is where the hummers meets the radius and ulna. The antagonistic muscle pair that is used to bend and straighten the elbow attached to the hummers.
The biceps is the flexed muscle, which makes the triceps the extensor muscle. So when the biceps contacts it bends the elbow and when the triceps contracts it straightens the elbow joint This is now the elbow Joint works and is the same concept in which other hinge joints such as the knees and fingers work. There is also a second type of Joint, which works differently from the hinge Joint. This is the ball-and-socket Joint. The ball and socket Joint is found in Joint such as the hip and the shoulder. In this kind of Joint the round end of one bone fits into a hollow depression in another bone.
The ball-and-socket Joint allows more movement in several directions, where as the hinge Joint only allows movements in two dimensions. This can be easily seen if you compare the wide-ranging swing of your upper arm or upper leg with the limited bending of your knee or elbow. That is why the human hip for instance can rotate because it is a ball-and-socket Joint. The mounded end of the femur (the ball) fits into the cupcake depression (the socket) in the pelvic bone. Sometimes you may hear people say that their hip or shoulder has popped out of its socket.
That means that the rounded bone has pooped out of the cupcake depression. However this can be fixed and popped back into place with the help of a doctor or a chiropractor. Anyway;ay the range of motion in ball-and-socket hip join is made possible by at least two pairs of muscles, which are oriented at right angles to each other. This is what provides flexibility of movement. This concept not only applies to the hip Joint, but also to all other ball-and-socket Joints such as the shoulder. Joints are not only made up of bones and muscles.
There are other important factors the play a role in healthy and well functioning Joints. These factors a cartilage and ligaments. Collagen is what forms the tough bands of connective tissue called ligaments. Ligaments Join bones at Joints, allowing the bones to move relative to one another while remaining attached. Ligaments are similar in structure to tendons, which connect muscles to bones. The other important factor for Joints is cartilage. Cartilage plays many roles in the vertebrate skeleton. For example during the development of an embryo, the skeleton forms first from cartilage that is later replaced by bones.
This happens by the steamboats, bone forming cells, invading and dissolving the cartilage. Cartilage is also what covers the ends of bones at Joints, supports the flexible part of the nose and ears connects the ribs to the sternum, also known as the breastbone, and provides framework for the larynx, trachea and bronchi of the respiratory system. On top of all that it also forms tough and shock absorbing pads that cushion he knee Joints and also form the intertribal discs between the vertebrae of the backbone. The living cells of cartilage are known as constructed.
These cells make a flexible, elastic, noncircular matrix of collagen that surrounds them and forms the cartilage. Cartilage cells however have a very slow metabolic rate. That is why damaged cartilage only repairs itself very slowly, if it is able to at all. Damaged cartilage can cause Joint problems and this is very hard to treat because of this extremely slow metabolic rate of the cartilage. There are multiple factors that make p Joints including the bone, the muscles attached to the bone, ligaments and cartilage. All of these work together to create well functioning Joint.
Bone is the most rigid tort tot connective tissue. It is very nard and is the major component of the vertebrate nonetheless, which provides support, protection and sites for muscle attachment. Bone resembles cartilage, however deposits of the mineral calcium phosphate harden it. Bones like those supporting your legs or arms are made of a hard outer shell of compact bone, with a spongy bone on the inside. The compact bone is very strong and dense and provides an attachment side for useless. Where as the spongy bone is lighter and rich in blood vessels.
Comparing bone to cartilage, bone is well supplied with blood capillaries. Steamboats, ecosystem and seacoasts are the three different bone cells, all with different functions. Steamboats are bone-forming cells and produce bone. Ecosystem are mature bone cells and are unable to produce more bone, yet may secrete substances that control the continuous remodeling of bone. Finally the bone cell seacoasts are bone-dissolving cells that dissolve bone. Both steamboats and seacoasts are also involved in the process of when bone replaces cartilage during he development of a human fetus.
The seacoasts dissolve the cartilage and the steamboats form the new bone. Each year about 5 % to 10% of your bone is dissolved by seacoasts and then replaced again by steamboats and this process is called remodeling. This allows the skeleton to alter its shape and composition in response to the demands placed on it. Bones that carry heavy loads or are subjected to extra stress become thicker, providing more strength and support. A professional tennis player for instance may have 30% more bone mass on his or her playing arm. Actually normal stress is an important factor in maintaining bone strength.
Bones of a body part that is immobilizers in a cast rapidly lose a great amount of calcium. Also people that have to use wheelchairs or lay in bed all the time initially lose about 2% of bone mass per month. Bed rest as well as space flight also reduces normal stress on the bones, causing bone loss. The human muscular and skeletal systems are very complex systems. There are many factors that are important in their well being and functioning. They give the ability to move; yet they also control various involuntary and unconscious things such s pumping blood through our body or moving food through our digestive system.