Homework 8/27/07

pg.17 # 2
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 for cells that usually varies only within certain limits. COPY An example of how this system works is when our bodies get hotter or colder. When we are cold we shiver and when we are hot we sweat. The digestive system takes the nutrients in your body and the respiratory system exchanges it for gases. The cardiovascular system distributes oxygen and nutrients to the cells and picks up waste. The urinary system takes the metabolic waste products from cells. The nervous system and endocrine system help coordinate the functions of the other systems.

Pg. 83 # 7, 11
7. Explain why the skin is sometimes referred to as the integumentary system?
The skin is sometimes referred to as the integumentary system because it consists of four tissue types. The skin also has several accessory organs such as hair, nails, sweat glands and sebaceous glands. A COVERING

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 is defined as the "relative constancy of the internal environment" because even through the external may change dramatically the internal is to stay normal and if not and the internal changes greatly you could get sick.
Negative feedback tends to promote homeostasis because it s a change in the internal environment that brings conditions back to normal. A positive feedback is the temperature of the body ????

pg. 245 #9
9. How does the muscular system help maintain homeostasis?
The muscular system helps maintain homeostasis because it is movement. The Contraction skeletal muscles associate with the jaw ad the tongue to allow you to chew your food. ???

pg. 271 #1,2
1. What are three functions of the nervous system?
The central nervous system which consists of the brain and the spinal cord, located in the middle of the body.
The peripheral system consists of the nerves outside of the CNS.
The CNS and ONS work together to smell and generate motion. FUNCTIONS??

2. What are the functions performed by the three types of neurons? Describe the structure and functions of the three parts of the neuron.
The sensory neuron takes the nerve impulse from a sensory receptors to the CNS and then the internueron receives input from the sensory system and sums it all up and finally takes it to the motor neuron that then takes the nerve impulses away from the CNS to a muscle or gland and then the effectors carry out the responses to the environmental changes to the internal or external.

pg.293 #1,4
1. Contrast exteroceptors and interoceptors.
Exteroceptors are sensory receptors that detect stimuli from outside the body such as taste, smell,vision, hearing, and equailibrium. Interceptors receive stimuli from inside the body such as blood pressure.

4. List the cutaneous receptors and the type of stimulus each respond to.
touch, pressure, pain, and temperature
touch can locate shape, size, and texture