nervous system

introduction to the nervous system

Michelle was riding her scooter when she hit a hole in the street and started to lose control. She thought she would fall, but, in the blink of an eye, she shifted her weight and kept her balance. Her heart was pounding, but at least she didnt get hurt. How was she able to react so quickly? Michelle can thank her nervous system for that ( Figure 1.1). The nervous system, together with the endocrine system, controls all the other organ systems. The nervous system sends one type of signal around the body, and the endocrine system sends another type of signal around the body. The endocrine system makes and releases chemical messenger molecules, or hormones, which tell other body parts that a change or a reaction is necessary. So what type of signal does the nervous system send? Controlling muscles and maintaining balance are just two of the roles of the nervous system. The nervous system also lets you: Sense your surroundings with your eyes and other sense organs. Sense the environment inside of your body, including temperature. Control your internal body systems and keep them in balance. Staying balanced when riding a scooter requires control over the bodys muscles. The nervous system controls the muscles and maintains balance. Prepare your body to fight or flee in an emergency. Use language, think, learn, and remember. The nervous system works by sending and receiving electrical signals. The main organs of the nervous system are the brain and the spinal cord. The signals are carried by nerves in the body, similar to the wires that carry electricity all over a house. The signals travel from all over the body to the spinal cord and up to the brain, as well as moving in the other direction. For example, when Michelle started to fall off her scooter, her nervous system sensed that she was losing her balance. It responded by sending messages from her brain to muscles in her body. Some muscles tightened while others relaxed. Maybe these actions moved her hips or her arms. The nervous system, working together with the muscular and skeletal systems, allowed Michelle to react to the situation. As a result, Michelles body became balanced again. The messages released by the nervous system traveled through nerves. Just like the electricity that travels through wires, nerve quickly carry the electrical messages around the body. Think about how quickly all this happens. It has to be really fast, otherwise Michelle would not have been able to react. What would happen if a car pulled out unexpectedly in front of Michelle? A signal would have to go from her eyes to her brain and then to her muscles. What allows the nervous system to react so fast. It starts with the special cell of the nervous system, the neuron.

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instructional diagrams

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questions

the brain is part of the nervous system.

-->  a. true

b. false

hormones are made by the nervous system.

a. true

-->  b. false

what two organ systems control all the other systems?

a) the nervous and skeletal systems

b) the nervous and muscular systems

-->  c) the nervous and endocrine systems

d) the muscular and endocrine systems

which of the following is a role of the nervous system?

a) to sense your surroundings with your eyes and other sense organs.

b) to control your internal body systems and keep them in balance.

c) to use language, think, learn, and remember.

-->  d) all of the above

what are the two main organs of the nervous system?

a) the heart and brain

-->  b) the brain and spinal cord

c) the spinal cord and the nerves

d) the brain and nerves

which of the following are parts of the nervous system?

-->  a) your eyes and other sense organs

b) your heart, which beats faster in an emergency

c) your skin, which senses the environment

d) all of the above

how does the nervous system help maintain homeostasis?

a) the nervous system prepares your body to fight or flee.

-->  b) the nervous system senses the environment inside of your body, including

c) the nervous system senses your surroundings.

d) all of the above

diagram questions

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