nevous+system+questions

page. 17 #2- what is homeostasis and how is it maintained? Give some examples that show how systems work together to maintain homeostasis.


 * Homeostasis is an internal environment of cells that usually varies only within certain limits (mainly temperature). HOMEOSTASIS IS AN INTERNAL ENVIRONMENT FOR CELLS THAT USUALLY VARIES ONLY WITH IN CERTAIN LIMITS -- DIRECTLY FROM BOOK.Homeostasis is maintained by the different systems in the body: the digestive system which takes in nutrients, the respiratory system which exchanges gases with the environment, the cardiovascular system distributes nutrients and oxygen to the cells and picks up the wastes, the urinary system gets rid of the waste produced by cells, the nervous and endocrine systems coordinate the functions of all the other systems.

page. 83 #7 Explain why the skin is sometimes referred to as the integumentary system.


 * the skin is something called an organ system which consists of many different accessory organs such as, hair, nails, sweat glands, and sebaceous glands.

page 83 #11- why is homeostasis defined as the " relative constancy of the internal environment?" does negative feedback or positive feedback tend to promote homeostasis? Explain.


 * Homeostasis' purpse is to keep the relative temperature of the internal environment consistant- therefore being called the relaitve constancy- it keeps the system consistant. negative feedback promotes homeostasis because it helps it regulate the "internal environment" when something is out of the ordinary the homeostasis kicks in and regulates the internal environment. CHECK SPELLING

page. 245 #9-How does the muscular system help maintain homeostasis?


 * The muscular system allows us to react to changes in the environment (such as going inside once you are too hot outside). The muscular system also movies CHECK SPELLING nutrients through the body and into the cells. The muscular system also makes the heart beat, pumping blood through the body.

Page. 271 #1- what are the three functions of the nervous system?


 * Recieve sensory input- sensory receptors in skin and other organs respond to external and internal stimuli by generating nerve impulses that travel by way of the Central Nervous System and the peripheral nervous system
 * processes the input recieved- the CNS sums up all of the input it recieves from the body
 * motor output- the body acts on the input GOOD

page. 271 # 2- What are the functions performed by the three types of neurons? Describe the structure and functions of the three parts of a neuron.


 * sensory neurons- takes nerve impulses from a sensory receptor to the CNS (sensory recepors detect changes in the environment)
 * Interneuron- is with in the CNS- they recieve all the information from the sensory receptors and other interneurons in the CNS- they then sup up all the input that they recieve before sending the information to the motor neurons
 * Motor neurons- thakes nerve impulses awa fromt he CNS to an effector (muscle fiber or gland)- an effector carries out the bodies responses to the environmental changes-external or internal

page. 293 #1- contrast exteroceptors and interoceptors.


 * exteroceptors are sensory receptors that detect stemuli from outside the body (taste, smell, vision, hearing, and equilibrium)- interoceptors receive stimuli from inside the body. Exteroceptors are not directly involved in homeostasis and continually send messages to the central nervous system regarding environmental conditions- interoceptors are directly involved in homeostasis and are regulated by NEGATIVE feedback.

page. 293 #4- List the cutaneous receptors and the type of stimulus each responds to.

- Meissner corpuscles, Merkel disks, root hair plexus- sensitive to fine touch - Pacinian corpuscles and ruffini endings- sensitive to pressure - free nerve endings in the epidermis- sensitive to temperature
 * Cutaneous receptors make the skin sensitive to touch, pressure, pain, and temperature.