The human body is composed of several different systems. Each system has a specific set of structures which are used to handle certain body functions. In order for the human body to function properly each of these systems must perform its assigned functions as well as work with other systems within the body. In some cases, outside factors like infectous agents work against the body. When a balance is achieved, the human body is said to be in homeostasis.
Unit Essential Question(s):
How do the human body systems interact to maintain homeostasis?
Describe how the human skeletal system is composed of bones, cartilage, ligaments and tendons. Explain that bones provide support and protection for the body, cartilage is a flexible material which is primarily used as a shock absorber in joints, ligaments are a flexible material which attach bones together and tendons are also a flexible material which attaches bones to muscles.
Explain that the skeletal systems gives shape and support to the body as well as provide protection for internal organs, assists muscles in locomotion and produce blood cells.
Explain that muscles are organs which are capable of relaxing and contracting. The movement of these organs provide a force which is used to move a body part. Discuss how there more than 600 muscles in the human body that in order for motion to occur these muscles tend to work in groups with one muscle relaxing and as another one contracts. Emphasis that because of this movement muscles cause motion to occur by pulling body parts into new positions.
Discuss that there are three different types of muscles. Cardiac muscle is located only in the heart and is constantly contracting, smooth muscle is located inside of your organs. Smooth muscle is involuntary and aids in the moving of materials throughout your organs. Skeletal muscle move the bones in order to provide motion. Skeletal are the most common type of muscle found in the human body. Skeletal muscles attach to bones using tendons.
LEQ: Number 3
HOTS: Comparing/Contrasting could be used to demonstrate the ET LEQ.
Explain that the function of the nervous system is to communicate conditions within the body and the surrounding environment. The nervouse system is composed of two divisions, the central nervous system and the peripheral nervous system. The central nervous system consists of the brain and the spinal cord and is considered to be the processing center for the entire body. The peripheral nervous system (PNS) is composed of all the other nerves in the body. The PNS connects the brain and the spinal cord to the rest of the body.
Discuss how the human body uses the stimuli it receives from internal and external sources to make adjustments so that the body can maintain homeostasis.
Explain that the circulatory system consists of the heart, veins, arteries, capillaries and blood. Discuss how the function of the circulatory system is to transport materials throughout the body to cells and then take waste products away from the cells.
Discuss how the heart is the pump for the system and then as it contracts and relaxes it creates pressure which moves the blood through out the body via the blood vessels (veins and arteries). Further explain that arteries carry blood away from the heart and veins carry blood to the heart. Misconception- Many people think arteries carry oxygenated blood and veins carry blood that lacks oxygen. Explain that capillaries connect arteries and veins together and are so thin that nutrients and oxygen can diffuse right through them.
Remind the students that the heart is composed of cardiac muscle that like all other tissues must have a continuous flow of blood to it in order for it to properly function and if this blood supply is blocked a heart attack may occur. Emphasis that heart diseases is the leading cause of death in the United States.
Explain that the respiratory system consists of the lungs, diapgragm, trachea, larynx, and the pharynx and its primary function is bringing oxygen into the body and help remove waste gases from the body.
Discuss how when the diagraphm contracts it causes the lungs to get bigger which creates a vaccum and pulls air into the lungs. The air flows into the lungs through large tubes called bronchi. At the end of bronchi are the alveoli which are tiny little sacs where gas exchange occurs between the lungs and the blood. Oxygen is transferred into the blood and waste gases like carbon dioxide and transferred back to the alveoli. The diaphragm then relaxes which causes the lungs to shrink. This forces the waste gases up the trachea and out of the body. Explain that the trachea is composed of cartilage and can be felt in the front of your neck. On top of the trachea sits the larynx, which is where the vocal chords are located and above the larynx is a passage way known as the pharynx. The pharynx connects the nasal and oral cavities with the esophagus and trachea. A thin flap sits on top of the trachea called the epiglottis and is designed to keep food and water from entering the trachea. When air first enters the body it comes in through the nasal passage where it is warmed and moistened before it passes to the larynx. Discuss how when air is brought into the lungs it is called inhalation and when air is removed from the lungs it is called exhalation..
Explain how when your body increases activity it causes the respiratory system to bring more air at a faster pace and when you are resting the breathing rate will decrease.
LEQ: Number 3
HOTS: Comparing/Contrasting could be used to demonstrate the ET LEQ.
Discuss the various parts of the digestive system including the tongue, salivary glands, esophagus, stomach, liver, gallbladder, pancreas, small intestine, large intestine, rectum and the anus.
Explain how when food enters the body through the mouth that the salivary glands secrete saliva which begins to chemically break down foor. The tongue helps to mix the food with the saliva. The teeth in your mouth help to mechanically breakdown the food so that it can be swallowed. As the food is swallowed it passes through the larnyx where the epiglottis covers the trachea and the food slides down into the esophagus which walls are lined with smooth muscles that help to squeeze and push the food down into the stomach. In the stomach their is hydrochloric acid that helps to chemically breakdown the food. Mechanical breakdown also occurs in the stomach. It takes food 2 to 4 hours to pass through the stomach and into the small intestine. The lump of food is now known as chyme and it will take 3-6 hours to pass through the small intestine. The liver and gall bladder secrete bile and the pancreas secretes various enzymes into the small intestine which help with digestion. The chyme will then move into the large intestine where the remaining water is removed from the chyme. The waste products are then removed through the anus. In total it takes about 24-72 hours for food to move through the entire digestive system depending upon what was eaten.
Discuss how the excretory system involves parts of the digestive system, urinary system, respiratory system and skin. The purpose of the excretory system is to remove waste products from the body.
Re-emphasis that the respiratory system eliminates gases and the digestive system eliminates solid wastes from the body.
Describe how the skin releases sweat as a way to remove excess water, sugar and urea.
Discuss how the kidneys are the major organ in the urinary system whose primary function is to filter excess water, salts and other wastes products which are no longer needed by the body. The liquid waste that is stored for removal is known as urine. The urine is moved to the bladder through tubes known as ureters. When th bladder is full the urine is then released into a tube called the urethra which releases the urine outside the body.
Note: The reproductive system is also being covered during the nurse lessons.
Re-emphasis that the male reproductive system consists of the penis, scotum and testes. The testes produce a sperm which are then combined with a fluid in the seminal vesicle to form semen. Semen is then released through the urethra and out of the body.
Re-emphasis that the female reproductive system consists of the ovaries, uterus and the vagina. The ovaries release one egg each month which then moves into the oviduct. If the egg is fertilized then the egg will move into the uterus where it will develop. If the egg is not fertilized then the wall of the uterus and the egg will break down be removed from the body.
Re-emphasis that sperm can survive inside the female body for up to three days and that the egg must be fertlized within 24 hours after it is released by the ovaries.
LEQ: Number 2
HOTS: Error analysis could be used to demonstrate the ET LEQ.
Discuss how the immune system is a complex system of organs, tissues and specialized cells whose primary function is to defend the body from infectious organisms and other foreign invaders.
Explain how the immune use other body systems like your skin, circulatory system, respiratory and digestive systems to help protect the body from pathogens.
Emphasize how the skin acts like a barrier to help keep pathogens from entering the body. The first internal line of defense starts when the air that enters your body passes over tiny hair-like structures called cilia which trap pathogens and dust on them with mucos. The enzymes in your mouth and acid in your stomach are capable of killing some of the bacteria that enters into your digestive system. The pancreas and liver both release enzymes designed to destroy pathogens. This line of defense is designed to stop and destroy most pathogens.
Explain that in some cases when a pathogen makes it into the circulatory system white blood cells will pick them up and digest them. White blood cells are specialized blood cells that are designed to trap and engulf pathogens within the body. In other cases, when the white blood cells can't completely destroy the pathogen the body will raise its temperature to try and destroy the bacteria. This is known as a fever.
Discuss how when tissue is damaged or infected it may become inflamed. Inflammation occurs because the capillaries in the damaged area enlarge and allow more blood to flood into the damaged area. White blood cells may also be brought in to deal with any pathogens that maybe in the area.
Explain that after the immune system fights an infection it can build up a specific immunity to that disease. The body recognizes the antigens located on the pathogen and developes specific antibodies to neutralize that particular pathogen. The next time the body is attacked by that pathogen it will send the specific antibody to destroy. This how immunity is developed. This form of immunity is known as active immunity. In other cases antibodies developed in other animal are placed within the human body, this is known as passive immunity. When you go to the doctors for a vaccination you being given a weakened form of an antigen. This is then injected into your body so that your immune system will develop antibodies to deal with the antigen. Vaccinations will only work to prevent a disease, they will not cure it.
Emphasize that medicine like antibiotics can kill most pathogens except for viruses. The only thing that can destroy a virus is your immune system.
LEQ: Number 3
HOTS: Constructing support could be used to demonstrate the ET LEQ.
Explain that diseases which infect the human body can be either viruses, bacteria, protists, fungi's or other animals.
Discuss how viruses are pieces of genetic material which are surrounded by coats of proteins. Viruses are infectous agents that are not alive, they can only reproduce within the host. Because viruses are not alive they cannot be killed and there is no medicine that will kill off the virus. The human body is the only thing that can defeat a virus.
Emphasize that even though viruses aren't alive they can still evolve and adapt to different environments. Some viruses can be prevented by vaccination.
Give some common examples of diseases caused by viruses are influenza, the common cold, smallpox, chickenpox, measles and AIDS.
LEQ: Number 2
Explain that bacteria are living, single-celled microscopic organisms which are believed to the earliest forms of life on the Earth. Some bacteria are prokaryotes and some are eukaryotes. Bacteria are found everywhere on the Earth and some are even found in your intestine. Not all bacteria are bad, in fact some bacteria are use dto produce medicines, make foods and aid our bodies in digestion. Some bacteria are pathogens and cause diseases within the human body.
Emphasize that bacteria can make you sick in many different ways. Some bacteria produce poisons or toxins which can lead to paralysis or death. Other types of bacteria can cause the cells to be killed off or damaged in certain parts of the body.
Discuss that because bacteria are living they can be killed by medicines. One of the most common treatments is the adminstration of antibiotics which are used to kill the bacteria cells and stop the infection. In recent times we have seen some forms of bacteria that have developed an immunity immunity to antibiotics. This is result of the bacteria evolving and adapting to the medicine.
Give some common examples of diseases which are caused by bacteria including strep throat, tetanus, tuberculosis and bacterial pheumonia.
LEQ: Number 3
HOTS: Constructing support or deductive reasoning could be used to demonstrate the ET LEQ.
Infectous Diseases- Protist, Fungi and Parasites
LEQ: Number 1
Discuss that protists are single or multicelled organisms which live in moist or wet surroundings. All protists are eukaryotic and are classified based upon how close they resemble plants, fungus and animals. There many different types of protists in the world and most are not harmful to humans.
Explain that disease causing protists are mostly are spread by drinking contaminated water and food or by bites or contact with some animal. Protists which cause diseases act like parasites as they move throughout the host.
Discuss some common diseases which are caused by protists such as malaria, african sleeping sickness and amoebic dysentery.
Point out that some protists infect plants and other types of animals like fish.
Explain that fungus are multicelled organisms that feed primarily by secreting digestive enzymes on their food source and then absorbing them back into the fungus. Some fungus feed on dead or decaying tissues while others act like parasites and feed on living tissue. Remind students the students that fungus that break down decaying tissue are considered decomposers.
Fungi can be both beneficial or pathogens to animals and plants. Fungi can cause skin diseases such as ringworm and athletes foot and more severe fungi can cause infections in the lungs.
Discuss how most fungal transmissions occur because the organism came in contact with the spores of the fungus.
Emphasize that fungal infections are very difficult to cure and often times will keep coming back.
Point out that penicillin, which is a fungi is used to fight bacterial infections.
Discuss how some animals like worms are parasitic and can cause diseases in humans. These organisms enter the human body and infect specific areas. In humans these parasites are often found attached to the walls of the intestines. In some cases these infections cause tissue damage, paralysis and even death.
Explain that often times these organisms enter the body by eating under cooked foods, foods that haven't been properly cleaned and cuts in the skin.
Give some examples of diseases caused by parasitic animals such as elephantitis and bedbug bites. Most parasite infections are treated with combinations of anti-parasite drugs and anti-inflammatories
LEQ: Number 2
HOTS: Comparing/contrasting or error analysis could be used to demonstrate the ET LEQ.