The Human Body

Unit Review Sheet

Facts and Definitions

Lesson 1: An Amazing Machine

• Cells combine to form tissue, tissue combines to form organs, and organs combine to form body systems.
• The nervous system controls your memory, thoughts, and feelings as well as your body's actions. It consists of the brain, spinal cord, and nerves.
• The respiratory system takes oxygen out of the air for use by the body. It is made up of your nose, larynx, trachea, bronchi, lungs, and diaphragm.
• The skeletal system is the framework for your body that protects organs. This framework consists of all your bones, cartilage, tendons, and ligaments.
• The muscular system, made up of skeletal and smooth muscle, works with your bones to help your body move.
• The cardiovascular system pumps blood throughout the body. It is made up of the heart, arteries and veins, blood vessels, and your blood.
• The digestive system provides nutrients to the body by breaking down food into molecules your body can use. It consists of the mouth, esophagus, stomach, small intestine, large intestine, liver, pancreas, and gall bladder.
• The defense system helps protect the body from sickness and damage by keeping pathogens out or attacking and killing those that get in.

Lesson 2: Sense Organs

• Taste buds can detect different tastes. Some areas of the tongue are less sensitive to certain tastes.
• The types of teeth are molars, premolars, incisors, and canines.
• The following are the parts of the eye:
  • retina: when hit by light, signals the optic nerve
  • iris: regulates the amount of light that enters the eye
  • lens: changes shape to focus the light from near or far objects
  • pupil: where light passes through the eye
  • cornea: bends the light rays and allows light to pass through the pupil
  • optic nerve: carries signals to the brain
• The cornea bends light as it travels through the pupil and to the lens. The lens focuses the light on the retina where the image is flipped. The retina carries a signal to the brain along the optic nerve, and the brain makes the image right side up in your mind.
• Sound travels from the outer ear to the brain. The pinna or outer ear catches the sound waves. The waves travel through the ear canal where they hit the eardrum and make it vibrate. Vibrations from the eardrum move to the ossicles (hammer, anvil, and stirrup). The vibrations push on the oval window that guards the cochlea where tiny hairs move and send nerve signals to the brain.

Lesson 3: The Digestive System

• The digestive system contains the following organs: liver, pancreas, gall bladder, small intestine, large intestine, mouth, esophagus, and stomach
• liver: makes bile, keeps poisons from going to the rest of the body, sends blood from the intestines to the heart
• pancreas: releases alkaline juices to break down starch, protein, and fats
• gall bladder: collects and stores bile
• small intestine: breaks apart foods into their simplest forms; lined with villi that absorb glucose, amino acids, and fatty acids to send to different parts of the body
• large intestine: receives watery waste of undigested food that is transformed into feces
• mouth: teeth, tongue, and saliva make food slimy so it can be swallowed
• esophagus: muscles here push food down from the throat to the stomach
• stomach: muscular bag where gastric juices help digest food

Lesson 4: Nutrition

• The nutrients our bodies need include water, vitamins, minerals, fats, proteins, and carbohydrates.
• Macronutrients are nutrients that you need in larger amounts; the three types are fats, proteins, and carbohydrates.
• Micronutrients are important vitamins and minerals that your body needs but in much smaller amounts.
• A healthy plate includes fruits, vegetables, grains, and proteins.
• Eating a number of different healthy fruits, vegetables, and whole grains is a great way to stay healthy.

Lesson 5: Respiratory and Cardiovascular Systems

• The organs of the respiratory system include the larynx, nose, trachea, diaphragm, and lungs.
• The organs of the cardiovascular system include the heart, blood, and blood vessels.
• The cardiovascular and respiratory systems work together to get oxygen to all parts of the body.
• Blood enters through veins into the atria of the heart, flows to ventricles, and out of the heart through arteries. This happens simultaneously in the right and left sides of the heart. The right side of the heart pumps blood to the lungs to collect oxygen. The left side of the heart pumps oxygen-rich blood to the rest of the body.

Lesson 6: Defense System

• Pathogens are tiny disease-carrying organisms.
• The defense system includes barriers to infection (the skin, mucus, stomach acid, tears, and saliva), and white blood cells that kill pathogens in the body (neutrophils, macrophages, B and T lymphocytes). You can also use your brain to prevent exposure to pathogens.
• The skin is the largest organ of your body and works like a wall to keep pathogens out.
• Neutrophils are the most common type of white blood cell. They gather at cuts and infections to fight off pathogens.
• Macrophages are white blood cells that eat and kill invading bacteria.
• T lymphocytes or killer T cells are specialized white blood cells that know how to kill specific pathogens.
• B lymphocytes produce antibodies that attack and disable pathogens.

Lesson 7: Muscular and Skeletal Systems

• Tendons connect muscles to bones.
• Voluntary muscles function when you consciously decide to move them.
• Involuntary muscles contract without your thinking about it.
• Ligaments are elastic bands that connect two bones.
• Cardiac muscle is an involuntary muscle found in the heart.
• Smooth muscle is found within the walls of hollow organs.
• Skeletal muscles are voluntary muscles that pull on the bones of the skeleton to make them move.
• Plane joints are bones that slide over one another in the wrists and ankles.
• Hinge joints allow bending and straightening of the knees, fingers, and elbows.
• Ball and socket joints involve one bone fitting into another bone, enabling a lot of movement in the shoulders and hips.
• Pivot joints involve one bone swiveling around the other; this joint connects your skull to your neck.

Lesson 8: Nervous System

• The brain, spinal cord, and nerves make up the nervous system.
• Nerve impulses are high-speed electrical signals that travel along neurons to send messages to the brain.
• A reflex is an automatic, split-second response to our environment that occurs when a message travels to the spinal cord and straight back to our body so we react accordingly. (For example, when you touch a hot pan, before you even feel pain, muscles pull your hand away.)

Final Project: Human Body on Display

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