ANATOMY AND PHYSIOLOGY I |1 Body Works in Balance: Messages from the Control Center Jennifer Kitchen HS120-01 Unit 9 Final Project Kaplan University June 20, 2011
ANATOMY AND PHYSIOLOGY I |2 The human body is an amazing structure that performs many wondrousfunctions. Each structure of the body has its own special functions, which maintain thebody in homeostasis. The word homeostasis can be understood by understanding theparts of the word. Homeo means “the same” and stasis means “staying”, sohomeostasis means “staying the same”. Although, the meaning of homeostasis is “tostay the same” the body really only maintains a relative uniformity due to the manyfactors that keep the body constantly changing because of internal and external factors(Thibodeau, & Patton, 2008). There are eleven organ systems within the bodyconstantly working to keep the body relatively stable and in balance. These systemswork together and when one system is not in balance it can affect the other systems.Functional Relationships: Balance and Control in the Body The body is complex and can be compared to a factory, which produces manyproducts and bi-products, and has an extensive computer control center. The nervoussystem made up of the brain, spinal cord, and nerves. It is the control center of thehuman body, receiving and interpreting stimuli, then transmitting impulses to organs(Thibodeau, & Patton, 2008). The brain uses the information it receives to coordinate allof the actions and reactions which occur in the body. By using action potentials(through neurons), the nervous system organizes rapid and precise responses tostimuli, making musculoskeletal system move the body and to pick up what is goingaround us by way of the senses. Neurons have three parts; dendrites receiveinformation and transmit the message to the cell body and the axon conducts messagesaway from the cell body (Farabee, 2006). This is like a two way receiver or telephone, a
ANATOMY AND PHYSIOLOGY I |3message is given and received and then a new message is transmitted as to what to doaccordingly with the first message.The junction between a nerve cell and another cell iscalled a synapse; this is where the message travels through. There is a space betweenthe transmitting and receiving cells which is called the synaptic cleft. To cross this gaprequires the actions of neurotransmitters, the chemicals and hormones that are themessages being sent and received (Farabee, 2006). This being so, many units in thewhole body must work together to get a job done; maintaining homeostasis. The integumentary system consists of the skin, hair, nails, and sweat glands. Itfunctions as a barrier to protect the body from the outside world and to retain bodyfluids, protect against disease, eliminate waste products, and regulate body temperature(Thibodeau, & Patton, 2008). The skin is like a full body, water-proof suit that breathes.The skin is the largest organ in the body, making up 12-15% of body weight and asurface area of 1-2 meters (that’s about 3 and a quarter to 6 and half feet) (Farabee,2006). It protects the internal organs and keeps helps maintain the body’s internalbalance by sweating to keep us cool and constricting sweat glands to help us staywarm. This happens when nerve impulses send signals to the skin and sweat glands,maintaining homeostasis. The skeletal system consists of the bones, cartilage, and joints. It provides theshape and form for our bodies as well as supporting and protecting our bodies, allowingbodily movement, producing blood cells, and storing minerals (Thibodeau, & Patton,2008).The skeletal system is complex and has been divided into sections for easierunderstanding. This system is like an inner armor, the axial skeleton, with gears thathelps a body move, the appendicular skeleton. The skull, vertebral column, and rib
ANATOMY AND PHYSIOLOGY I |4cage are part of the axial skeleton consists and the appendicular skeleton consists ofthe bones of the appendages (arms and legs) and the pectoral and pelvic girdles(Farabee, 2006). The axial skeleton protects the inner organs of the body, keepingthem from becoming crushed by each other. The appendicular skeleton, in cooperationwith the muscular system, moves the body. These bones include the moveable jointswhich are connected (bones to joints and joints to bones) by ligaments. Themovements of the body are made when an impulse is sent via motor units to themuscles that move the bones and joints. The muscular systemmade up of muscle tissue and is the power behindmovement with the help of the motor units of the nervous system. These muscle tissueswork to move the body and move materials through the body. Muscles are bundles ofcells and fibers that work by contractions (Thibodeau, & Patton, 2008). Quite simply,muscles make us move by tightening and relaxing. There are 3 different types ofmuscle tissue, each with a specific purpose. Skeletal muscles run the full length of amuscle and are striated (they got stripes, these are the fibers). These muscles cells aremulticellular. The skeletal muscles are voluntary and are connected to bones bytendons. Smooth muscle cells are spindle shaped and uninucleate (having a singlenucleus) and are located in the walls of hollow organs, (stomach, intestine, uterus, andureter). Smooth muscles are involuntary and do such things as churn the food in thestomach and move the urine from the kidney to the bladder. Cardiac muscle cells arestriated and uninucleate. They are the heart muscles that make the blood flow byinvoluntary, rhythmic contraction(Wick, 1997). All the movements of the muscular
ANATOMY AND PHYSIOLOGY I |5system are dependent on the nervous system which sends impulses to cause thecontractions that make the muscular tissues contract or relax. The endocrine system works in a corresponding manner with the nervoussystem. It is like the center of operations, as the nervous center is the control center.The endocrine system consists of a collection of glands; the pituitary, the hypothalamus,adrenal, and thyroid glands, the pancreas, the ovaries and testes. This systemregulates, coordinates, and controls a number of body functions by secreting chemicals,known as hormones. These secretions help control moods, growth and development,and metabolism, maintaining homeostasis (Thibodeau, & Patton, 2008).The endocrinesystem secretes chemical known as hormones to accomplish its duties. Homeostaticfeedback controls these secretions. In this center of operations the pituitary gland is themaster gland, signaling for hormones to be produced by other the other glands(Farabee, 2006). Both the nervous system and the endocrine system arecommunication centers of the body and aid the body’s organ systems to functioncorrectly and in relation to each other. Unlike the quick impulses of the nervous system,the endocrine system has a slower but longer lasting effect.Concept of Homeostasis: The Senses and Nervous System Work Together The senses allow humans to perceive the World around them. Without thesenses people would run into walls, not recognize other people and objects, and wouldnot be able to feel pain or smell when foods were spoiled. The senses are comprised ofthe general sense organs (microscopic receptors) widely distributed throughout thebody which give us the ability to feel what we touch and the localized special sense
ANATOMY AND PHYSIOLOGY I |6organs of the eyes, ears, nose, and taste buds which vary according to the sense theyare responsible for (Thibodeau, & Patton, 2008). The sense organs (and the sensesrelated to them) send to the brain important information about the environment and helpkeep humans stay away from danger, find food, and relate to each other. The eyes are very complex structures, with photoreceptors that capture light andtransmit to the brain what the brain changes into picture, and probably the most useful.The ears, the organs for hearing, are very complex and constantly working. Hearing isaccomplished by vibration of tiny drum (tympanic membrane), tiny bones, and a tube(cochlear duct) within the ear. The vibrations cause fine “hairs” within the ear totransmit to the brain what one hears. The sense of smell is extremely useful. The nosecontains smell receptors, olfactory receptors, which have links to the memory part of thebrain and tells humans what is good or bad, by smell, in the environment. Taste isconnected to smell through the throat/nose area at the back of the mouth, which is whyif a food smells bad a person will not want to eat it. Taste is accomplished by the tastebuds sending nervous impulses to the brain via the gustatory cells, where taste isregistered. Touch, the sense that comes from the sensory receptors that are distributedthroughout the skin, react to stimulation from the environment (Thibodeau, & Patton,2008). When a person feels heat from a flame the reaction is to pull away. When achild touches their mother’s soft skin the sensation travels to the brain and the child willfeel comforted. These sensory receptors also tell a person about movement andposition of the body.
ANATOMY AND PHYSIOLOGY I |7 The 5 senses consist of organs with specialized cells that have receptors forspecific stimuli. These cells contact the nervous system, through cranial nerves, andtherefore the central nervous system, to tell a person what is going on in theirenvironment. This is very important in keeping a person alive and maintaininghomeostasis. What a person sees, hears, smells, tastes, and feels can mean a lot inany environment but in today’s world where so many things are happening at oncethere could be such a thing as sensory overload, but somehow the brain works out whatis going on and helps maintain a balance. The systems of the body work together and when one system is not in balance itcan affect the other systems. The human body is an awesome and complex structurethat performs many amazing functions without a person every really noticing. Eachstructure of the body has its special functions, which maintain homeostasis, internallyand externally. The body may not have a solid balance but it is relatively stable.Maintaining this relative balance is no small feat for such a compact unit, the body, butwith these systems all doing their part it is possible.
ANATOMY AND PHYSIOLOGY I |8ReferencesFarabee, M. J., (2006). On-Line Biology Book.Arizona; Estrella Mountain Community College.Retrieved from http://www2.estrellamountain.edu/faculty/farabee/biobk/biobooktoc.html .Thibodeau, G. and Patton, K., (2008), Structure & Function of the Body.Mosby Elsevier; St. Louis, MO.Wick, S., (1997). Human Anatomy and Physiology: biology 2740- biology 2840. Retrieved from http://www.unomaha.edu/hpa/index.html .