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A body system is a collection of body organs and parts, which interact together to carry out a designed task. It is the most advanced organization in your body and the final level of the progression from cells to tissues to organs and then systems. These systems range from reproducing a cell to developing a new human being, circulating blood to catching oxygen from the air and even digesting food through grinding and chemical transformations, absorbing nutrients and getting rid of waste. Systems work with other systems to allow the body to maintain homeostasis ( stable internal environment, allowing cells to survive).
( Dr Ben Kim, April 2009)
"Your cells are the basic living units that make up your body."
"Groups of cells come together to form specialized tissues."
"Groups of tissues come together to form your organs." ( Dr Ben Kim, April 2009)
The mammalian body is an ideal example of an intricate and complex system of organs, with countless interacting parts keeping the organism alive. (An average mammalian body on a single day "103,689 times, their blood travels 168,000,000 miles, their digestive system processes 7.8 pounds of waste, and their lungs take in 438 cubic feet of air"). (Neil Izenberg, M.D, 2004)
Interconnectivity of the systems:
Systems rarely work alone, for example organs are capable of being apart of numerous systems. All of the systems in an organism are interconnected. An ideal example of this is the circulatory and respiratory systems . When blood circulates through the body, after a period of time it is in need for a fresh batch of oxygen from the air. When the blood reaches the lungs ( vital organ of the respiratory system), the blood is actually reoxygenated. (Neil Izenberg, M.D, 2004)
The stomach plays a crucial role in the digestive system, it constantly interacts with the endocrine system and releases hormones to throughout your body.
The respiratory system
The respiratory system is a complex organ system composed of multiple cell types involved in a variety of functions.
The respiratory system primary function is to remove the oxygen out of the lungs and output carbon dioxide and minute amount of oxygen. This is done through breathing inhaling oxygen and exhaling carbon dioxide. Essentially the exchange of gases in this system is getting the oxygen to the blood.
The space between the alveoli and the capillaries is the anatomy\ structure of this exchange system; its physiological uses of the exchanged gases will depend on the species of the organism.
In mammals and humans this structure will usually consist of anatomical features such as lungs, respiratory muscles and airways. These anatomical features of the respiratory system as the mouth nose and trachea is where the respiration is achieved. Firstly Oxygen enters the through the mouth or the nose and then passes through the larynx which is a characteristic feature of the trachea in many mammals which the passage way to the chest cavity. The trachea splits into two smaller tubes called the bronchi. Then a similar processes each bronchi leads directly into the lungs (which is an essential respiratory organ) and divides, which forms bronchial tubes. They then link up to tiny sacs called alveoli.
(Perkins, M. 2003.)
The average adult's lungs encompass about 600 million of the spongy, air-filled sacs, which are surrounded by capillaries. This inhaled oxygen exceeds into the alveoli area of the lungs and then diffuses through the capillaries into the arterial blood. While this is occurring the blood full of waste from the veins then releases its carbon dioxide into the alveoli region. Carbon dioxide pursues the same pathway out of the lungs when a mammal exhales. This helps to maintain the acid-base balance of the body
The diaphragm is described as a mass of muscles; it is situated across the bottom of the chest cavity. The diaphragm job in the respiratory system is to assist in pumping the oxygen out of the lungs and pull oxygen into them. Breathing happens when the diaphragm contracts and relaxs, when it contracts the oxygen is drawn into the lungs and when it relaxes the carbon dioxide is pumped out of the lungs.
The nervous system
Mammals have the most multifaceted nervous systems on our earth, with humans being one of the most intricate. The nervous system is an organ system contains a network of specialized neurons that coordinate the physical and behavioral actions of a mammal and transmits signals between different parts of the body. Signals from the body are sent through nerve endings ( receptors) to the brain, where neurotransmitters send an additional signal to allow a mammals to feel pain or another form of sensory information.
This process of transmitting signals from the body to the mammalian brain takes less than one-hundredth of a second. The amount of sensory information delivered will vary of the development of the mammalian brain. Small mammals such as rats encompass smooth brains which are restricted to transmitting a limited amount of sensory information to the their nervous system. In comparison to humans who have highly developed brains and are able to send a large amount of information to their nervous system.
About a Mammal's Nervous System | eHow.com http://www.ehow.com/about_4565581_mammals-nervous-system.html#ixzz0wpdG9Oqg
Most mammals the nervous system will consist of two primary parts.
Central nervous system: It is the part of the nervous system which job is to integrate the information that it receives from and designs the activity of all parts of the body in mammals (vertebrates) it consists of the brain, spinal cord and retina. A bone or a blood brain barrier protects the central nervous system.
Peripheral nervous system: This consists of the nerves and ganglia outside the brain and the spinal cord. This is how the system connects the central nervous system to the organ and limb. These regions are all interconnected by means of advanced neural pathways. The peripheral system is divided into the somatic nervous system (is the voluntary control of body movements through the course of moment through skeletal muscles) and autonomic nervous system (control system which functions mainly below the level of consciousness and is responsible for the direction of visceral functions. The autonomic nervous system affects the heart rate, digestions, respiration rate, salivation, perspiration, diameter of the pupils, urination and sexual arousal.
The circulatory system
"The circulatory system is an organ system, which passes such nutrients as amino acids and electrolytes, also gases hormones, blood cells to and from cells situated in the body this helps fight diseases and also stabilizes the body temperature and PH this maintains homeostasis." ( Peter. E. Porman, 2007)
Its drives the constant movement of the blood, the system uses the pumping of the heart, the organ that acts as the system's engine. Arteries have a purpose of bringing oxygen rich blood to all the cells, and then the veins retrieve the blood, this is so it can be oxygenated once again and that the wastes can be removed.
The ideal centre of the system is the heart combined with the network of vessels from the "cardiovascular machinery" ( Britannica illusrated science library) . The heart beets more than 30 million times a year and 2 billion times in an average persons life time. " ( Britannica illusrated science library) . With a single beat it pumps around 5 cubic inches of blood.
The general structure of the circulatory system of the rat is almost identical to that of humans. The structure of the circulatory system of the rat is basically identical to the humans. In a rat the pulmonary circulation transports blood through the lungs for oxygenation and then back to the heart. Systematic circulation moves blood through the body after it has left the heart.
The excretory system
This system can be described as a passive biological system which purpose is to remove excess or dangerous waste from the organism. This helps the organism maintain homeostasis and prevent the damage to the body.".
The whole organism thrives on the adequate function of this system, as it is a specially designed system that removes metabolic waste products from the interstitial fluid into the blood capillaries and eventually deposits the material at a specific area, that caters for complete removal from the body. Not every species of animals use the same paths to excrete as humans, Excretion applies to metabolic waste products that cross a plasma membrane. The primary organs of excretion are the bladder, kidneys, and skin.
Liquid wastes such as nitrogenous substances, urea and excess water is removed from the body through the kidneys. "Each mammalian has two kidneys lieing asymmetrically on the dorsal body wall of the upper area of the abdomen, the right kidney is more anterior than the left". ( Leigh Zaykoski, Decemeber 18th 2009 Blood enters the kidney through the renal artery and leaves through the renal vein. As the kidneys are so important in maintaining stability of the internal environment they receive about 25% of the body's blood flow.
Each individual kidney there is an estimated one million microscopic nephrons; in these areas is where the filtering of the blood happens. " The nephron, an evolutionary modification of the nephridium, is the kidney's functional unit". (M.J. Farabee May 18 2010). An individual nephron encompasses a cluster of capillaries, which is a glomerulus. A bowman's capsule encircles each glomerulus. Blood flows under such a high pressure through the glomerulus, causing water, glucose and urea to enter the bowman's capsule.
However after this blood filtration white blood cell, red blood cells and proteins remain. Blood then goes on to the blood vessels and then wraps around the renal tubula.
While this is occurring reabsorption happens, glucose and chemicals are reabsorbed into the blood. Around 90 % of the water is removed during the filtration phase, but then is returned to the blood in the reabsorption phase. After these phases only wastes such as urine, urea, inorganic salts are left in the nephron. The cleansed blood is delivered into the veins which carry the blood from the kidneys back to heart. After the waste is filtered from the blood and collected as urine in each kidney , it leaves the kidney by ureters and collects in the bladder. The bladder distends to store urine, after a period of time leaves through the urethra.
http://web.mac.com/drakem55/Cardiovascular/May_files/09%20Rat%20Anatomy%20Lab.pdf ( amazing website)
The reproductive system:
"The excretory and reprodutive systems of vertebrates are closely integrated and are usually studied together as the urogenital system". However, they do have different functions: the excretory system removes wastes and the reproductive system produces gametes (sperm & eggs)."
Also the reproductive system creates an environment for developing embryo and regulates hormones related to sexual development.
The human reproductive system is a network of organs within an organism which work together with a sole purpose of reproduction. Other vital components to the reproductive system are numerous non-living components such as fluids, hormones and pheromones. Differing to other body system, each sex of the organism will have distinct physical difference's. These differences provide for a mishmash between two individuals, which offers a larger chance of genetic fitness for offspring.
The major organs for the reproductive system encompass the external genitalia (penis\vulva) additionally internal organs including the gamete (The gonads develop in the same dorsolateral region as the kidneys. Gonads are initially equipped with two sets of ducts). which produces gonads. Most other vertebrates usually will have a highly similar system consisting of gonads, ducts, and openings, however can be a great diversity of physical adaptations and reproductive strategies depending on the organism.
Human reproduction starts as internal fertilization by sexual intercourse. In this process the erect penis of the male is inserted into the females vagina, this occurs until the male ejaculates which is filled with sperm and is inserted into the vagina. After this process the sperm travels through the vagina and cervix into the uterus or fallopian tubes, this is for the fertilization of the ovum. The sex of the embryo is determined at conception by its chromosome content. "In man 46+XX is female, 46 +XY is male." The gonads on the other hand first are created of an indifferent type ( same in both sexes). The germ cells, which future purpose is to be come eggs they actually sperm develop in an other part of the embryo from the gonads, (closer to the heart actually). They will travel through the tissue of the embryo to the gonald. This works efficiently because by the time the germ cells has arrived, the gonald has decided and prepared its gender. (In the male changes are under the influence of the Y chromosome (we know this because of the few unfortunates who don't have one , or who have an unusual number of X chromosomes ). ( Dr J Jonhson 2005). The integral part of the male devlopment is the creation of the interestitial cells, hormone producing testosterone cells of the testis. In females it is a quite a dissimilar process, the testicular cords of a male which is known as the medullary cords deteriorate as there is no Y chromosome to facilitate them.
If this fertilization and implantation is successful, the gestation of the foetus this will take place in the females uterus for a usual period of nine months, this development is known as pregnancy. The gestation ends with birth and the labor, which is the muscle of the uterus contracting, cervix dilating and ultimately the baby passing out through the vagina.
Each group of students will be supplied with a wax dissection tray, pins and the dissection kit consisting of scissors, forceps and probes and a dead rat specimen. Note that scalpels are not required for, and indeed are detrimental to, a successful dissection.
Place the rat ventral side upon the wax block and, stretching out the arms and legs, fasten it into position by pushing pins through the distal ends of the radius and ulna and the tibia and fibula.
With the rat firmly positioned into place, use your foreceps to pinch and lift a section of skin from the centre of the rats "abdominal section" . Using scissors, carefully snip a small longitudinal spilt through the skin of the rat. Take particular care not to cut through the peritoneum, or abdominal wall, as you do so.
Then inserting the Blunt point of scissors under the rats skin, carefully cut upwards to the chin of the rat, and downwards to the anus. Then proceed to cut from the centreline along the stretched out limbs. When this is completed, pull back the layer and fasten it with pins to the wax box. Then, in like manner, carefully proceed to cut open the abdominal wall and fasten it back as well.