Lesson 2: The Nerve Cell and the Nerve Impulse (PDF)

NERVE CELL NERVE What are the parts and function of the nervous system? Picture of a child touching a hot object Who can cite other situations/ experiences related to the one shown in the  Group Activity “How Fast is Your Reaction?” Guide Questions: Q1. With which hand did you catch the...

NERVE CELL NERVE What are the parts and function of the nervous system? Picture of a child touching a hot object Who can cite other situations/ experiences related to the one shown in the  Group Activity “How Fast is Your Reaction?” Guide Questions: Q1. With which hand did you catch the ruler faster when your eyes were opened? When your eyes were closed? Q2. Did you catch the ruler faster with your eyes opened or closed? Q3. Explain why a message moving along nerve pathways takes time? Q4. Describe the nerve pathway that the message followed when you saw the ruler fall? What are the parts of a nerve cell? Describe its function. How can a nerve cell or neuron Carry impulses from one part of the body to The Nerve Cell ( Neurons ) – the basic unit of the nervous system. It has a cell body containing the nucleus. Basic parts of a neuron dendrites cell body This Photo by Unknown Author is licensed under CC BY-SA This Photo by Unknown Author is licensed under CC BY-SA This Photo by Unknown Author is licensed under CC BY-NC-ND The Nerve Impulse Neurons are cells with the ability to carry signals or impulses. Thoughts, emotions, learning, and many body functions are carried by nerve impulses in the neurons. A nerve impulse is a combination of an electrical charge and a chemical reaction. An electrochemical signal moving along a neuron.  The nerve impulse is sent by neurotransmitters ( a chemical produced when a nerve impulse comes to the end od an axon) from one neuron to another through a gap called synapse.  The nerve impulse is sent by neurotransmitters ( a chemical produced when a nerve impulse comes to the end od an axon) from one neuron to another through a gap called synapse. Neurons have the special ability to carry signals or impulses. A nerve impulse is an electrochemical signal moving along a neuron. The space between neurons is called synapse. A stimulus is any factor in the environment that influences behavior. A response is a reaction to a condition or stimulus. An organism must be able to respond to a stimulus in order to survive. Reaction time is the length of time between application of a stimulus and detection of a response. When a receptor such as an organ perceives a stimulus, the impulse is sent to the brain by the sensory neurons, which then transmit information from one nerve cell to another. As the message reaches the brain, it processes the information and commands an effector such as a muscle or an organ to respond. The message coming from the brain is sent  A Nervous Trip Direction: Choose the letter of the best answer. 1.All of the following situation shows a response to stimulus EXCEPT? A.Makahiya leaf closes as it is being touched. B.You feel the pain when somebody hits you. C.A dog continues to sleep while somebody is walking around him. D.Your friend laughs as she watches a comedy movie. 2.Reaction time is the length of time between application of a stimulus and detection of a response. Which is an example of a delayed reaction situation? A.You jump when you step on a sharp object. B.Your mother shouted “ouch” upon touching hot pot. C.A boy hit by ball and cry after a while. D.A girl screams as light off inside a movie house. 3. Motor neurons transmit impulses in the PNS or Peripheral Nervous system. In line with this function, which does not belong to the group? A.Sensory nerves B. Muscles C. Glands D. Neurons 4. Which shows the correct order of stimuli – response scenario? I.Message coming from the brain is sent through the motor neurons. II.A receptor such as an organ perceives a stimulus. III.The impulse is sent to the brain by the sensory neurons, which then transmit information from one nerve cell to another. IV.A message reaches the brain; it processes the information and commands an effector such as muscle or an organ to respond. A. II, III, IV, I B. II, IV, I, III C. I , II, III , IV D. II, I, IV , III 5.All of the following health programs and activities can help promote healthy lives in relation to human nervous system care EXCEPT. A.New Born Screening B.Availability of Instant Foods C.Stimulating Brain Care Development Program D.Proper Diet and Exercise