CK12 Life Science

The lungs, skin, kidneys, and large intestine are all part of the excretory system. The urinary system is made up of the kidney ...

homeostasis Theabilitytomaintainastableinternalenvironmentdespiteexternalchanges. kidney Organ that filters and cleans the blood ...

Image Sources (1) Piotr Michał Jaworski. PioM.png. GNU-FDL. (2) J.C. Rojas.http://www.flickr.com/photos/jcrojas/523383835/. CC-B ...

(18) http://commons.wikimedia.org/wiki/File: Centrilobular_emphysema_865_lores.jpg. (b)Public Domain, COPD. ...

Chapter 20 Controlling the Body 20.1 Lesson 20.1: Nervous System Lesson Objectives Identify the functions of the nervous system ...

Figure 20.1: Staying balanced when riding a scooter requires control over the body’s muscles; the nervous system controls the mu ...

because they are electrical impulses. Think about flipping on a light switch when you enter a room. When you flip the switch, it ...

Motor neurons carry nerve impulses from the central nervous system to internal organs, glands, and muscles. Both types of neur ...

Somepeoplehavelowlevelsoftheneurotransmitterserotoninintheirbrain. Scientiststhink that this is one cause of depression. Medicat ...

The Brain What weighs about 3 pounds (1.5 kilograms) and contains up to 100 billion cells? The answer is the human brain. Thebra ...

The cerebrum is divided into a right and left half, as shown inFigure20.5. Each half of the cerebrum is called ahemisphere. The ...

trunk. They also include nerves of the scalp, neck, and face. Nerves that supply the internal organs and glands are part of the ...

peripheral nervous system below. Figure 20.7: The central nervous system interprets messages from sense organs and internal orga ...

nervous system. Human beings have several senses. They include sight, hearing, balance, touch, taste, and smell. We have special ...

girl inFigure20.9is using her somatic nervous system to control the muscles needed to play the violin. Her brain sends commands ...

Figure 20.10: The woman pictured here is just pretending to be frightened, but assuming that she really was scared, think of whi ...

Explain how one neuron transmits a nerve impulse to another neuron.(Intermediate Compare and contrast the three main parts of t ...

cell body Part of a neuron that contains the nucleus and other organelles. central nervous system Part of the nervous system tha ...

sensory neuron Neuron that carries nerve impulses from sense organs or internal organs to the central nervous system. somatic ne ...

Introduction Think about all the ways that students use their sense of sight during a typical school day. As soon as they open t ...