Zach-Questions

p. 17 #2 p. 83 #7, 11 p. 245 #9 p. 271 #1, 2 p. 293 #1, 4

P. 17 #2 (What is homeostasis and how is it maintained? Give some examples of systems in the body helping to maintain homeostasis.) Homeostasis is an internal environment for cells that usually varies only within certain limits. HOMEOSTASIS IS AN INTERNAL ENVIRONMENT FOR CELLS THAT USUALLY VARIES ONLY WITH IN CERTAIN LIMITS -- DIRECTLY FROM BOOK. Homeostasis is maintained by using different systems in the body to trade off with external elements. For instance, the digestive system take in nutrients from the food we eat and things we drink. The respiratory system exchanges gases with the environment. These systems are a few of those that help maintain homeostasis. The most important ones would probably be the nervous and endocrine systems because they operate the other systems.

P.83 #7 (Explain why the skin is sometimes referred to as the integumentary system.) The skin is the outermost layer to the human body and that reason alone is why the skin is sometimes referred to as the integumentary system.


 * 1) 11 (Why is homeostasis defined as the “relative constancy of the internal environment?” Does negative feedback or positive feedback tend to promote homeostasis? Explain.) p.78-81 the human body has to react to the habitat around it. And the human body needs a mechanism by which it can adjust internally to the conditions it is facing externally. That system is homeostasis. Positive feedback normally promotes homeostasis because it is such a helpful mechanism. NEGATIVE FEED BACK

p. 245 #9 (How does the muscular system help maintain homeostasis?) p.p.242-243 The muscular system helps to maintain homeostasis by providing heat to maintain body temperature. Muscles also protect and support internal organs.

p. 271 #1 (What are thee functions of the nervous system?) p.248 USE YOUR OWN WORDS AND PHRASING 1. The nervous system receives sensory input 2. The CNS performs integration; summing up all the input it receives from the rest of the body. 3. The CNS generates motor output; nerve impulses go from the CNS by way of the PNS to muscles and glands. 1. Sensory Neurons—takes nerve impulses from a sensory receptor to the CNS. 2. Interneurons—receive input from sensory neurons and also from other interneurons in the CNS. 3. Motor Neurons—take nerve impulses away from the CNS to an effector. (muscle fiber or gland) 4. Structure—The sensory neurons are in the front of the nervous system, the interneurons in the middle, and the motor neurons in the back.
 * 1) 2 (What are the functions performed by the three types of neurons? Describe the structure and functions of the three parts of a neuron.) p.249

p. 293 #1 (Contrast exteroceptors and interoceptors.) p.274 Exteroceptors are sensory receptors that detect stimuli from outside the body, such as those that result from taste, smell, vision, hearing, and equilibrium. Interoceptors receive stimuli from inside the body, such as blood pressure, water-salt balance, and pH of the blood.

• Free nerve endings—pain, heat, cold • Merkel disks—touch • Krause and bulbs—touch • Root hair plexus—touch • Meissner corpuscles—touch • Pacinian corpuscles—pressure • Ruffini endings—pressure
 * 1) 4 (List the cutaneous receptors and the type of stimulus each responds to.) p.276-277