The human Musculoskeletal System
1.1 The human skeleton has multiple roles, for example, supporting body weight and protecting the brain and nerves in the spinal column. There are many different types of bones that come in various different shapes and sizes related to their specific function.
The skeletal system is made up of five different types of bones; long, short, flat, sesamoid and irregular. Long bones help to support body weight and facilitate movement whereas short bones provide movement and support in the wrist and ankle joints. Sesamoid bones protect tendons in the knees, hands and feet from strain and damage, and flat bones protect internal organs such as the brain, lungs, heart and pelvic organs.
https://www.visiblebody.com/learn/skeleton/types-of-bones
1.2 The synovial joint is the most common type of joint found in the body. At synovial joints, the articular surfaces of bones are covered with smooth articular cartilage. This gives the bones of a synovial joint the ability to move smoothly against each other, allowing for increased joint mobility.
Synovial joints are subdivided based on the shapes of the articulating surfaces of the bones that form each joint. The six types of synovial joints are pivot, hinge, condyloid, saddle, plane, and ball-and socket-joints. The six types of synovial joints allow the body to move in a variety of ways. Pivot joints allow for rotation around an axis, such as between the first and second cervical vertebrae, which allows for side-to-side rotation of the head. The hinge joint of the elbow works like a door hinge. The articulation between the trapezium carpal bone and the first metacarpal bone at the base of the thumb is a saddle joint. Plane joints, such as those between the tarsal bones of the foot, allow for limited gliding movements between bones. The radiocarpal joint of the wrist is a condyloid joint. The hip and shoulder joints are the only ball-and-socket joints of the body.
http://library.open.oregonstate.edu/aandp/chapter/9-4-synovial-joints/
1.3 Skeletal muscles consist of thousands of muscle fibres that extend across the length of the muscle. Each muscle fibre is composed of multiple contractile units called myofibrils which run the length of each muscle fibre. There are many types of skeletal muscles, one being the soleus muscle, this is located in the lower leg, its main function is to stabilize the ankle joint and helps to maintain posture.
Skeletal muscles are important for holding your bones in the correct position and prevents your joints from dislocating. Some skeletal muscles in your face are directly connected to your skin, for example, your eyelids. The smallest contraction of one of these muscles will change your facial expression.
http://www.bbc.co.uk/science/humanbody/body/factfiles/skeletalsmoothandcardiac/heart_beat.shtml
1.4
Most body movement is caused by skeletal muscle contraction. Skeletal muscles contract and relax to move the body. Messages from the nervous system cause these muscle contractions. The whole process is called the mechanism of muscle contraction and it can be summarized in three steps:
A message travels from the nervous system to the muscular system, triggering chemical reactions.
The chemical reactions lead to the muscle fibers reorganising themselves in a way that shortens the muscle–that’s the contraction.
When the nervous system signal is no longer present, the chemical process reverses, and the muscle fibers rearrange again and the muscle relaxes.
https://www.visiblebody.com/learn/muscular/muscle-contractions
2.1 The respiratory system includes the lungs as well as other organs that help to get oxygen into the blood and carbon dioxide out of the blood. The conducting zone of the respiratory system carries oxygen into the lungs and carbon dioxide out of the lungs. The respiratory zone is where oxygen and carbon dioxide move into and out of the blood.
Respiratory systems include lungs and other organs that help get oxygen into and carbon dioxide out of the body. Lungs are contained within the thoracic cavity, the section of the human body encased by the rib cage and separated from the abdominal cavity by the diaphragm. The thoracic cavity includes other organs such as the heart and esophagus. Human lungs are made of three lobes on the right side and two lobes on the left. The left lung contains what we call the cardiac notch, as the heart takes up this space within the thoracic cavity. https://study.com/academy/lesson/gross-anatomy-of-the-airway-and-lungs-conducting-respiratory-zones.html
2.2 The alveoli are clusters of small sacs at the end of the bronchial tubes.
These sacs fill with air with each inhalation.
The alveoli are surrounded by capillary beds. Both the alveoli and the capillary walls are one cell thick and allows for the diffusion of Oxygen O2 and Carbon Dioxide CO2 between the lung tissue and the blood. [M. Brian 2018] https://socratic.org/questions/how-does-the-structure-of-the-alveoli-relate-to-its-function-in-the-lungs
2.3 Pulmonary ventilation increases because of a rise in tidal volume and respiratory rate to meet increased oxygen demands. Oxygen delivery during strenuous exercise is limited by cardiovascular function. Your pulse is just an indication of your heart rate as your arteries expand each time the ventricles pump blood out of the heart. Your heart speeds up to pump extra food and oxygen to the muscles. Breathing speeds up to get more oxygen and to get rid of more carbon dioxide.
When a fit person, such as an athlete, exercises the pulse rate, breathing rate and lactic acid levels rise much less than they do in an unfit person. The time which it takes for pulse and breathing rate to return to normal is called the recovery time, and the fitter you are, the shorter your recovery time.
If you don’t eat and drink properly, you will impair your homeostatic response. Your body needs water to maintain a normal temperature and blood volume, but sweating can dehydrate you. Dehydration decreases your blood volume, which can halt blood flow to your skin and cause you to become overheated. Consequently, you will experience impaired muscular strength and endurance, decreased alertness and increased risk of injury. https://www.livestrong.com/article/369714-how-does-the-body-maintain-homeostasis-in-response-to-exercise/
3.1 There are three types of blood vessel in the human body; Arteries, Veins and Capillaries. Arteries carry blood away from the heart. The largest is the aorta. The circulation to all the body except the lungs is called the systemic circulation and carries oxygenated blood. Arteries divide into smaller arterioles which divide again and again and eventually become capillaries.
Veins are large blood vessels which carry blood back to the heart. Systemic veins carry deoxygenated blood. The largest veins are the superior and inferior vena cava, which return blood to the heart from the upper body and lower body respectively. Veins have a system of valves to prevent back flow.Unlike the artery the vein has a poorly developed middle layer, the tunica media. This is because the vein is not working under pressure and does not stretch in the same way as the artery.
Capillaries are the smallest blood vessels. The average diameter is eight micrometers with a very thin wall of 0.2 micrometers. The body has approximately 100,000 km. of capillaries. They are the site for exchange of gases, nutrients and waste between circulation and body tissues. http://www.firstaidforfree.com/what-are-the-three-types-of-blood-vessels-and-their-functions/
Mammals have a double circulatory system, which means that one circuit links the heart and lungs, the other circuit links the heart with the rest of the body, this type of system has advantages, including higher blood pressure and so a greater flow of blood to the tissues. http://www.bbc.co.uk/schools/gcsebitesize/science/add_ocr_gateway/living_growing/circulatoryrev4.shtml
3.2 Structure and Function in the Mammalian Heart Mammals have a double circulatory system; blood passes through the heart twice during a complete circuit. Having a double circulatory system means that our pressure is maintained and oxygen is efficiently obtained from our lungs. The heart contains four chambers: two upper chambers called the atria and two lower chambers called the ventricles. The two sides of the heart are divided by the septum which prevents blood flowing between the two separate sides. The heart is composed of cardiac muscle which can tirelessly contract and relax rhythmically. Because of having thinner cardiac muscle than the ventricles, the atria produce less force when they contract. On the other hand, blood is pushed out with greater force once it is in the ventricles because of the thicker cardiac muscle in the walls of the ventricles. The muscle of the left ventricle is thicker since blood is pushed through to the rest of the body from here. http://www.markedbyteachers.com/gcse/science/structure-and-function-in-the-mammalian-heart.html
3.3 Blood, by definition, is a fluid that moves through the vessels of a circulatory system. In humans, it includes plasma (the liquid portion), blood cells (which come in both red and white varieties), and cell fragments called platelets. Plasma is the main component of blood and consists mostly of water, with proteins, ions, nutrients, and wastes mixed in. Red blood cells are responsible for carrying oxygen and carbon dioxide. White blood cells are part of the immune system and function in immune response. https://www.khanacademy.org/science/biology/human-biology/circulatory-pulmonary/a/components-of-the-blood
3.4 By the time blood reaches the capillary beds from an artery, it is at high pressure and this forces blood plasma out. The plasma leaves the capillary and becomes tissue fluid. As the blood plasma moves through the capillary bed towards the vein, pressure drops and stops plasma being squeezed out.
Tissue fluid acts as a bridge in the diffusion of chemicals between the capillaries and the cells of the tissue. Oxygen and glucose diffuse from the blood into the tissue fluid and then into the cells. Carbon dioxide and urea diffuse from the cells into the tissue fluid and then into the blood. http://www.bbc.co.uk/schools/gcsebitesize/science/triple_ocr_21c/further_biology/circulation/revision/4/
The tonsils, adenoids, spleen and thymus are all part of the lymphatic system. The primary function of the lymphatic system is to transport lymph, a fluid containing infection-fighting white blood cells, throughout the body. The lymphatic system primarily consists of lymphatic vessels, which are similar to the circulatory systems veins and capillaries. The vessels are connected to lymph nodes, where the lymph is filtered. https://www.livescience.com/26983-lymphatic-system.html