The Skeletal System

Skeletal, Muscular, and Nervous Systems The Skeletal System

Functions of the Skeletal System: Your skeletal system provides a living structure for your body. Strong bones, including the vertebrae of your spine, support your upper body and head. The skeleton plays a crucial role in movement by providing a srong, stable, and mobile framework on which muscles can act. Your skeletal system also protects your internal tissues and organs from trauma. The skull, vertebrae, and ribs create protective cavities for the brain, the spinal cord, and the heart and lungs, respectively. Bones store minerals such as calcium and phosphorus, which are important to the health and strength of the skeleton and to various esential processes in your body. Bone marrow, a connective tissue within bones, produces new red blood cells and white blood cells. '

Skeleton video: http://www.youtube.com/watch?v=d1aSMhAAWg8

Structure of the Skeleton: Your skeletal system consists of 206 bones that can be classified in two main groups. The axial skeleton consists of the 80 bones of the skull, spine, ribs, vertebrae, and sternum, or breastbone. The appendicular skeleton is composed of the remaining 126 bones of the upper and lower limbs, shoulders, and hips. Types of Bones: Bones may be classified according to their various traits, such as shape, origin, and texture. Four types are recognized based on shape. These are long bones, short bones, flat bones and irregular bones. Long bones have a long central shaft, called the diaphysis, and two knobby ends, called the epiphysis. In growing long bones, the diaphysis and epiphysis are separated by a thin sheet of cartilage. Examples of long bones include bones of the arms and legs, the metacarpals of the hand, metatarsals of the foot, and the clavicle. Short bones are about as long as wide. The patella, carpels of the wrist and tarsals of the ankle are short bones. Flat bones take several shapes, but are characterized by being relatively thin and flat. Examples include the sternum, ribs, hip bones, scapula and cranial bones. Irregular bones are the oddshaped bones of the skull, such as the sphenoid, the sacrum and the vertebrae. The common characteristic of irregular bones is not that they are similar to each other in appearance, but that they can't be placed in any of the other bone categories.

Bones may also be classified based on their origin. All bone (as well as muscles and connective tissue) originates from an embryonic connective tissue called mesenchyme, which makes mesoderm, also an embryonic tissue. Some mesoderm forms the cartilaginous skeleton of the fetus, the precursor for the bony skeleton. However, some bones, such as the clavicle and some of the facial and cranial bones of the skull, develop directly from mesenchyme, thereby bypassing the cartilaginous stage. These types of bone are called membrane bone (or dermal bone). Bone which originates from cartilage is called endochondral bone. Finally, bones are classified based on texture. Smooth, hard bone called compact bone forms the outer layer of bones. Inside the outer compact bone is cancellous bone, sometimes called the bone marrow. Cancellous bone appears open and spongy, but is actually very strong, like compact bone. Together, the two types of bone produce a light, but strong, skeleton. http://www.ask.com/bar?q=what+are+the+four+types+of+bones%3F&page=1&qsrc=0&zoom=How+Many+Bones+Are+in+the+Human+Body%7C4+Examples+of+Types+of+Bones%7CWhat+Are+Bones+Made+of&ab=0&u=http%3A%2F%2Fscience.jrank.org%2Fpages%2F6161%2FSkeletal-System-Types-bone.html

What bones are made of: BONES ARE MADE OF CELLS AND LIVING PARTS OF YOUR BODY. PLUS THEY ARE ALSO MADE OF STRONG STRING MATERIAL CALLED COLLAGEN. BONES ARE STORAGE PLACE FOR MINERALS. BONES HAVE A JELLY LIKE RED AND YELLOW MARROW. YELLOW BONE MARROW STORES FAT AND SUGAR. THE OUTER LAYER IS CALLED HARD BONE AND THE SPONGY BONE IS A HONEYCOMB OF BONE CELLS WITH SPACES BETWEEN THEM. http://www.ask.com/bar?q=What+Are+Bones+Made+of&page=1&qsrc=2070&zoom=How+Many+Bones+Are+in+the+Human+Body%7CBone+Marrow%7C4+Examples+of+Types+of+Bones&ab=0&u=http%3A%2F%2Flibrary.thinkquest.org%2FJ002557F%2Fbones.htm

Nervous System

Nervous system: set of nerves, ganglions and nervous centers that receive sensory signal. Commands and coordinates vital functions.

Brachial plexus: network of nerves of the arm.

Intercostal nerve: cord conducting nerve impulses between the ribs.

Radial nerve: cord conducting nerve impulses in the area of the radius

Median nerve: main cord conducting nerve impulses in the upper limb.

Ulnar nerve: cord conducting nerve impulses in the area of the elbow.

Lumbar plexus: network of nerves of the lower back.

Sciatic nerve: cord conducting nerve impulses in the area of the thigh and lower leg.

Common peroneal nerve: cord conducting nerve impulses along the inside of the lower leg.

Superficial peroneal nerve: cord conducting nerve impulses of the muscles and skin of the leg.

Digital nerve: cord conducting nerve impulses of the fingers.

Sacral plexus: network of nerves of the sacrum

Spinal cord: substance belonging to the nervous system, found in the holes of the vertebrae.

Cerebellum: nervous centre situated under the brain.

Cerebrum: seat of the mental capacities.

Nervous system video:http://www.youtube.com/watch?v=cqvoV4R7T2g What is the nervous system?: The nervous system is the major controlling, regulatory, and communicating system in the body. It is the center of all mental activity including thought, learning, and memory. Together with the endocrine system, the nervous system is responsible for regulating and maintaining homeostasis. Through its receptors, the nervous system keeps us in touch with our environment, both external and internal. Like other systems in the body, the nervous system is composed of organs, principally the brain, spinal cord, nerves, and ganglia. These, in turn, consist of various tissues, including nerve, blood, and connective tissue. Together these carry out the complex activities of the nervous system.The various activities of the nervous system can be grouped together as three general, overlapping functions: Sensory Integrative Motor Millions of sensory receptors detect changes, called stimuli, which occur inside and outside the body. They monitor such things as temperature, light, and sound from the external environment. Inside the body, the internal environment, receptors detect variations in pressure, pH, carbondioxide concentration, and the levels of various electrolytes. All of this gathered information is called sensory input. Sensory input is converted into electrical signals called nerve impulses that are transmitted to the brain. There the signals are brought together to create sensations, to produce thoughts, or to add to memory; Decisions are made each moment based on the sensory input. This is integration. Based on the sensory input and integration, the nervous system responds by sending signals to muscles, causing them to contract, or to glands, causing them to produce secretions. Muscles and glands are called effectors because they cause an effect in response to directions from the nervous system. This is the motor output or motor function.

Muscular System

Aerobic and anaerobic muscle activity: At rest, the body produces the majority of its ATP aerobically in the mitochondria without producing lactic acid or other fatiguing byproducts. During exercise, the method of ATP production varies depending on the fitness of the individual as well as the duration, and intensity of exercise. At lower activity levels, when exercise continues for a long duration (several minutes or longer), energy is produced aerobically by combining oxygen with carbohydrates and fats stored in the body. Activity that is higher in intensity, with possible duration decreasing as intensity increases, ATP production can switch to anaerobic pathways, such as the use of the creatine phosphate and the phosphagen system or anaerobic glycolysis. Aerobic ATP production is biochemically much slower and can only be used for long-duration, low intensity exercise, but produces no fatiguing waste products that can not be removed immediately from sarcomere and body and results in a much greater number of ATP molecules per fat or carbohydrate molecule. Aerobic training allows the oxygen delivery system to be more efficient, allowing aerobic metabolism to being more quickly. Anaerobic ATP production produces ATP much faster and allows near-maximal intensity exercise, but also produces significant amounts of lactic acid which render high intensity exercise unsustainable for greater than several minutes. The phosphagen system is also anaerobic, allows for the highest levels of exercise intensity, but intramuscular stores of phosphocreatine are very limited and can only provide energy for exercises lasting up to ten seconds. Recovery is very quick, with full creatine stores regenerated within five minutes.

Muscular system video:http://www.youtube.com/watch?v=EdHzKYDxrKc Cardiac Muscle: Heart muscles are distinct from skeletal muscles because the muscle fibers are laterally connected to each other. Furthermore, just as with smooth muscles, they are not controlling themselves. Heart muscles are controlled by the sinus node influenced by the autonomic nervous system. Smooth muscles: Smooth muscles are controlled directly by the autonomic nervous system and are involuntary, meaning that they are incapable of being moved by conscious thought. Functions such as heart beat and lungs (which are capable of being willingly controlled, be it to a limited extent though) are involuntary muscles but are not smooth muscles. Control of muscle contraction: Neuromuscular junctions are the focal point where a motor neuron attaches to a muscle. Acetylcholine, (a neurotransmitter used in skeletal muscle contraction) is released from the axon terminal of the nerve cell when an action potential reaches the microscopic junction, called a synapse. A group of chemical messengers cross the synapse and stimulate the formation of electrical changes, which are produced in the muscle cell when the acetylcholine binds to receptors on its surface. Calcium is released from its storage area in the cell's sarcoplasmic reticulum. An impulse from a nerve cell causes calcium release and brings about a single, short muscle contraction called a muscle twitch. If there is a problem at the neuromuscular junction, a very prolonged contraction may occur, tetanus. Also, a loss of function at the junction can produce paralysis. Skeletal muscles are organized into hundreds of motor units, each of which involves a motor neuron, attached by a series of thin finger-like structures called axon terminals. These attach to and control discrete bundles of muscle fibers. A coordinated and fine tuned response to a specific circumstance will involve controlling the precise number of motor units used. While individual muscle units contract as a unit, the entire muscle can contract on a predetermined basis due to the structure of the motor unit. Motor unit coordination, balance, and control frequently come under the direction of the cerebellum of the brain. This allows for complex muscular coordination with little conscious effort, such as when one drives a car without thinking about the process. http://en.wikipedia.org/wiki/Muscular_system

Muscle Types Cardiac: Cardiac muscles are involuntary and found only in the heart. They are controlled by the lower section of the brain called the medulla oblungata, which controlls involuntary action throughout your body. Think about how horrible it would be to have to consciously tell your heart to beat, with the consequence of forgetting being death. What about when you went to sleep!?! But luckily enough, the medulla oblungata does all that for us.Your heart cells come in long strips, each containing a single nucleus, one of the key factors in determining which of the three classes any particular muscle is. Located at the walls of the heart, its main function is to propel blood into circulation. Contraction of the cardiac tissue is caused by an impuse sent from the medulla oblungata to the SA nerve located at the right atrium. Smooth Your smooth muscles, like your cardiovascular muscles, are involuntary. They make up your internal organs, such as your stomach-hyper link, throat-hyper link, small intestine-hyper link, and all the others, except your heart. Unlike cardiovascular muscles, smooth muscles are generally spherical, as most other human cells are, and each contains one nucleus. Skeletal The skeletal muscles are the only voluntary muscles of your body, and make up what we call the muscular system. They are all the muscles that move you bones and show external movement.Unlike either of the other two classes, skeletal muscles contain multiple nuclei because of its large size, being in strips up to a couple of feet long. The muscles we have in our body are divided into three classes of muscles: cardiac, smooth, and skeletal. Usually, when we think of muscular system we often only remember the skeletal muscles because they make up what is recognized as the muscular system. The muscular system, composed of over 600 muscles, come in a variety of shapes and forms. Diffrences between each muscle are recognized by location, function, structure, and the way they are contracted. Muscle-Bone interactions LEVER SYSTEM A lever is a rigid bar on which a given load is moved with supporting help from a fulcrum. A fulcrum is a fixedpoint on which lever can move in diffrent ways or angles. The whole muscular system interacts in this kind of way with the skeletal system-hyperlink. Given a load the muscles pull the bone up or in any direction againsrt the load. Your joints-hyperlink usualy seem to be the fulcrum on which you move the lever or bone. For example, try lifting a book with your hand and puting your elbow on the table. You can move the book in any direction with the help of the joints in your elbow, and the book is lifted in any direction due to the muscles contractions.Skeletal muscles can be broken down into groups based upon the type of movement they portray. The movement of the muscle is based upon the type of joint upon which the muscle works. Skeletal muscles can't expand, or make themselves longer, but they can contract, or make themselves shorter, so they generally work in pairs. One contracts, and in doing so stretches the other, and reverses its effects on the joint. For example, when you contract your major arm muscle, which is called the bicep, in return the lower arm muscle, called the tricep, extends. So as you contract one muscle the other one extends. These effects can be broken down into groups of their own: flexors, extensors, adductors, and abductors. Flexors and extensors become plantarflexors and dorsiflexors, respectively, when located within either the wrist or ankle joints. Flexors Flexors bend at the joint, decreasing the interior angle of the joint. The humorous, or bicep, is a flexor of the elbow joint, bringing the fist towards the shoulder. If a flexor appears in either the wrist or ankle joints, it becomes a plantarflexor.

Extendors Opposites of flexors, extensors unbend at the joint, increasing the interior angle. The humorous, or tricep, is an extensor of the elbow joint, taking the fist farther away from the shoulder. If an extensor is found in the wrist or ankle joints, it becomes a dorsiflexor. Abductors Abductors take away from the body, like lifting the arm to the side. Abd- means to take away, like abduct and abdicate. Spreading out your fingers uses abductors, because you are taking away your fingers from an imaginary line running down your arm.

Adductors Adductors, the opposites of abductors, move toward the body. Add- means to increase or include. By lowing an arm raised to the side, or moving your fingers together while keeping them straight, your muscles are adducting. Tendons and Ligaments As fascinating as they are, muscles alone can't do the job. At every joint, tendons and ligaments also help out. Muscles wouldn't be very useful alone because they don't directly connect to the bone, so even if they contract, they wouldn't be moving anything. Instead, muscles are connected to tendons, when themselves are connected to the bones. When the muscles contract, they pull on the tendons, which in turn pull on the muscles, and that causes movement.But without ligaments, that movement wouldn't be too useful because it would not be directed movement. Without ligaments, instead of bones bending or rotating about each other when muscles contract, they would slide by each other. Ligaments are what hold the bones together. They connect at the ends of muscles and keep them from slipping and sliding, and force them to bend. Major Skeletal Muscles The muscual body is divide into ten diffren areas where muscles can be found: facial, neck, shoulder, arm, forearm, thorax, abdomen, hip, pelvis/thigh, leg. Facial In the facial are one finds all the muscles wich move the face. Orbicularis oculi-sound are the two muscles that move the eye are. Frontalis-sound and Temporalis-sound are the two muscles which move the forehead and sides of your head. Zygomaticus-sound ands Masseter-sound are the two muscle that work in conjunction to move tyoou jaw and upper lip area. Orbicularis oris-sound is the muscle which moves your lips. Neck The neck area is almost entirely moved by the sternohyoid-sound and Sternocleidomastoid-sound. These muscles allowthe neck to move your head left and right. They work with the platysma muscle to control how far you can move your head left and right. What allows your head to move up and down is the trapezius-sound. The trapezius is so large that it extend down to the shoulder and thorax area. The trapezius is a good example of how some muscles are named by their shape. the trapezius looks just like a trapezoid. Shoulder A group of muscles all work together to move the whole shoulder area. This group takes into account the trapezius-sound, deltoid-sound, infraspinatus-sound, teres major-sound, and the rhomboid major-sound. The rhomboid major is called so because its shaped like the geometric shape of a rhombus. Along with the help of the ball and socket joint-hyperlink in your shouder, these gruop of muscles allow your arm to throw a softball, pick things over your head, and give your arms a good strech early in the morning. Arm Most known amongst teenage weight lifters is the arm area. The famous bicep brachii-sound is the muscle that allows you to bring your forearm close to your body and form a huge ball of muscle wich catches a lot of attention amongst weight lifters. The tricep brachii-sound and brachialis-sound are the two other muscles located in the arm region. These muscles allow a person to do push-ups! Forearm A majority of the muscle in the forearm help control a part of the arm. Amongst these is the Berachiodialis major-sound, palmaris longus-sound, and Flexor carpi radialis-sound. The name of the flexor carpi radialis is a good example of how muscles are named by their function and location. This muscle is named carpi because of the bones that it helps move, the carples. Also, the name of radialis is made by the bone that its attached to, the radius. Thorax The thorax is the set of muscles which carrying your head, arms, stomach, and any other upper body areas. These muscles are the trapezius-sound and latissimus dorsi-sound. Usually, the majority of the muscles of the thorax can be damaged easly is one dose not streach before excersice, or lifts a heave load. Abdomen The abdominal area consists of the muscles that allows you to bend down and move your waist from side to side. The interanl oblique-sound and external oblique-sound are the muscles that move your body from left to right. The Transversus abdominus-sound and Rectus abdominus-sound, along with the trapezius-sound an latissimus dorsi-sound allow you to bend down and grab objects. Hip Only two muscles make up the hip area. These are the gluteus medius-sound and gluteus maximus-sound. Probably the laziest muscles in the whole system the gluteus set of muscles are used only to sit down on. Pelvis/Thigh An overlaping of muscles is what makes this area so firm. The pelvis area is usualy refered to as the upper part of the leg. Muscles like the pectineus-sound and illiopsoas-sound , which help support the upper leg area are known as pelvic muscles. Thigh muscles are very rich in capillaries and support the whole body. The upper thigh muscles are abductor longus-sound, Gracilis-sound, Sartorius-sound, and Tensor fasciae latea. The lower thigh muscles are rectus femoris-sound, vastus lateralis-sound and medialis-sound. Located in the back of your leg are the hamstrings-sound. These muscles help you run, jump, and walk. Leg Helping the thigh region support the body is the Leg region. These muscles like the Gastrocnemius-sound, soleus-sound, porenius longus-sound, and Tibialis anterior-sound absorb the impact when one walks and runs. they also give beter cordination for moving. the thigh region trust the body forward while the leg region coordinates where it should be thrusted and where it should stand.

http://en.wikipedia.org/wiki/Muscular_system