NN+Nervous+System

Homeostasis is the environment that allows for normal cell activity. Major variation in temperature and homeostasis cannot be maintained and the cells die. To avoid reaching these extremes, the body has natural processes such as shivering and sweating to either increase or decrease the internal temperatures. Many of the systems work together to try and maintain homeostasis such as the digestive system taking in nutrients, and the cardiovascular system distributes these same nutrients to the cells and picks up the waste, which is evacuated through other systems like the respiratory system.
 * p. 17 (2) What is homeostasis, and how is it maintained? Give some examples that show how systems work together to maintain homeostasis**

7) Explain why the skin is sometimes referred to as the integumentary system?** Skin is sometimes referred to as the integumentary system because an organ is made up of two or more different tissues to accomplish a task, and skin is made up of four tissues with several accessory organs such as hair, and together they accomplish several tasks vital to maintaining homeostasis. Homeostasis is defined as the "relative constancy of the internal environment" because homeostasis is the internal environment that allows normal cells and tissues to thrive, and since the cells can live within a certain range of temperatures, the body has to simply maintain the "relative constancy." Negative feedback is the operation that more closely maintains homeostasis because negative feedback creates a small fluctuation to go back to homeostasis.
 * p. 83 (7, 11)
 * 11) Why is homeostasis defined as the "relative constancy of the internal environment?" Does negative feedback or positive feedback tend to promote homeostasis? Explain.**

The muscular system performs several tasks that help maintain homeostasis such as the heart, which allows nutrients that are essential to homeostasis to get to their destinations. When your the temperature is too cold, muscles will constrict, causing the outer blood vessels to constrict, keeping the blood closer to the internal organs in order to keep warm.
 * p. 245 (9) How does the muscular system help maintain homeostasis**?

1) What are the three functions of the nervous system?** The first function is for the nerves to sense what is going on around them and to respond to stimuli, the second function is for the CNS (central nervous system) to put all the different signals from the different nerves together to understand the person's surroundings, the third function is for the CNS to send an impulse to the muscles and glands to act upon the information it received from the first two functions. The first type of neuron is the sensory neuron, and the sensory neurons take the nerve impulses from the nerves to the CNS. The second type of neuron is the interneuron, which live inside the CNS and receives the signals from the sensory neurons and other interneurons. The final type of neuron is the motor neuron. The motor neuron takes the impulses from the CNS to the effectors, which control our reactions to the impulses sent by the nerves through the neurons.
 * p. 271 (1, 2)
 * 2) What are the functions performed by the three types of neurons? Describe the structure and functions of the three parts of a neuron.**

1) Contrast exteroceptors and interoceptors.** The main difference between the two is that exteroceptors react to stimuli outside the body, and interoceptors react to stimuli inside the body. The first three types of cutaneous receptors are sensitive to touch, they are the meissner copuscles, the merkel disks, and the root hair plexus. There are two types of cutaneous receptors that respond to pressure, they are called the pacinian corpuscles and the ruffini endings. There are also receptors that are sensitive to temperature and are just free nerve endings in the epidermis, the are generally known as cold receptors and warmth receptors.
 * p. 293 (1, 4)
 * 4) List the cutaneous receptors and the type of stimulus each responds to.**