Reference no: EM133214767

Activity - Nervous System

Part A

Use Anatomy & Physiology Revealed 4.0 to identify and answer questions related to the nervous system. To begin, choose the 3. Tissues module and select the Animations icon. View the Nervous tissue overview animation and answer the corresponding questions.

Question 1. What is the basic functional unit of the nervous system? What is it specialized to do?

Question 2. What are three important functional properties of the answer to question 1?

Question 3. Which part of the cell receives, integrates, and sends nerve impulses?

Question 4. Which process directs information away from the cell body?

Question 5. Which process directs information toward the cell body?

Question 6. What is a synapse?

Question 7. Which four glial cells are found in the CNS?

Question 8. Which two glial cells are found in the PNS?

Part B

Click on the Module dropbox and select 7. Nervous, then click the Histology icon (microscope). From the topic dropbox, select Axon hillock. Click on Structure information button (left column "i") to answer the following questions.

Structure type: Axon of multipolar neuron

Question 1. Where does it terminate?

Question 2. Conveys what type of nerve impulses?

Question 3. Also known as?

Structure type: Dendrites of multipolar neuron

Question 1. Convey what type of nerve impulses?

Question 2. Receive information from what?

Question 3. Are they myelinated?

Structure type: Nucleus of neuron

Question 1. What are its three main functions?

Question 2. What is its location?

Part C

Switch to the Animations icon and view the following animations to answer the corresponding questions.

Action potential generation

Question 1. When the cell membrane is at its resting potential, are the activation gates of voltage-gated sodium ion channels and potassium ion channels open or closed?

Question 2. What happens when threshold is reached?

Question 3. Why does depolarization occur?

Question 4. What event decreases the diffusion of sodium ions?

Question 5. What causes the membrane potential to be slightly more negative than the resting value?

Question 6. What reestablishes the resting membrane potential?

Action potential propagation

Question 7. What happens to the inside of the cell membrane during an action potential with respect to the outside?

Question 8. Can an action potential travel backward?

Question 9. What is the period during which an action potential cannot be generated called?

Chemical synapse

Question 10. Action potentials arriving at the presynaptic terminal open which channels?

Question 11. When calcium ions diffuse into the presynaptic cell, what chemical is released from synaptic vesicles?

Question 12. What do the chemicals from question 11 diffuse across?

Question 13. Binding to ligand-gated channels on the postsynaptic cell allows which ion to diffuse into the postsynaptic cell?

Question 14. What effect does this have on the membrane potential of the postsynaptic cell?

Question 15. What level must be reached to produce an action potential?

Part D

The brain, along with the spinal cord, comprises the body's central nervous system. The average adult brain weighs about 3.0-3.5 lbs and has about 100 billion neurons, each with hundreds or thousands of synapses.

Choose the 7. Nervous module and select the Animations icon. View the Divisions of brain animation and answer the corresponding questions.

Question 1. What are the four major regions of the brain?

Question 2. What are the five lobes found in each cerebral hemisphere?

Question 3. The cerebrum is considered the seat of intelligence and is responsible for what four major functions?

Question 4. What is the primary function of the cerebellum?

Question 5. What three structures make up the diencephalon?

Question 6. Which part of the diencephalon serves as a major processing and relay center?

Question 7. What are five major functions of the hypothalamus?

Question 8. What three structures make up the brainstem?

Question 9. Which part of the brainstem is involved in visual and auditory reflexes?

Question 10. Which part of the brainstem contains nuclei concerned with respiration, blood pressure, and heart beat?

Part E

Click on the Dissection icon (scalpel) and select Brain from the topic dropbox and Lateral from the view dropbox. Click on the layer tag buttons in the bottom left side of the screen to find structures marked by green pins. Find the following structures and answer the corresponding questions.

Question 1. The frontal lobe is involved in what four functions?

Question 2. The parietal lobe is involved in what three functions?

Question 3. The temporal lobe is involved in what three functions?

Question 4. The occipital lobe is the primary area for which special sense?

Question 5. The cerebellum is involved in what two functions?

Question 6. What does the corpus callosum connect?

Question 7. The thalamus is involved in what two functions?

Part F

The spinal cord is involved in sensory and motor innervation (via spinal nerves), provides a two- way conduction pathway for signals between the body and brain, and serves as a major reflex center. The spinal cord runs through the vertebral canal of the vertebral column and extends from the foramen magnum (large hole at the base of the skull) to the level of the first or second lumbar vertebrae in the lower back.

Click on Structure List (Clipboard upper left). Click on the topic dropbox and select Spinal cord, then select Overview from the view dropbox. Choose Spinal cord as your structure type and click on Layer 5 in the bottom left corner to dissect the spinal cord and answer the following questions.

Question 1. Number of pairs of spinal nerves in the cervical region:

Question 2. Number of pairs of spinal nerves in the lumbar region:

Question 3. Number of pairs of spinal nerves in the sacral region:

Question 4. Number of pairs of spinal nerves in the thoracic region:

Question 5. Number of pairs of spinal nerves in the coccygeal region:

Question 6. List the five regions of the spinal cord in order from most superior to most inferior.

Part G

Choose the 7. Nervous module and select the Animations icon. View the following animations and answer the corresponding questions.

Nerves are cordlike organs that can contain thousands of axons (nerve fibers) bound together by connective tissue. Most nerves contain axons from both sensory and motor neurons. Nerves have a high metabolic rate and need a plentiful blood supply, which is provided by blood vessels that penetrate the connective tissue coverings of the nerve. The human body has 12 pairs of cranial nerves that primarily innervate structures of the head and neck, and 31 pairs of spinal nerves that innervate the rest of the body.

Typical spinal nerve

Question 1. How are spinal nerves named?

Question 2. What connects each spinal nerve to the spinal cord?

Question 3. Which root contains bundles of afferent (sensory) nerve fibers?

Question 4. Which root contains bundles of efferent (motor) nerve fibers?

Question 5. What do dorsal rami innervate?

Question 6. What do ventral rami innervate?

Reflexes are rapid, stereotyped motor responses to specific stimuli that are not under conscious control. The five components of a reflex arc include the receptor, sensory neuron, integration center (typically a neuron), motor neuron, and effector (muscle or gland).

Reflex arc

Question 7. What initiates the reflex?

Question 8. Where does the axon of a sensory neuron end?

Question 9. How is an impulse typically transmitted from a sensory neuron to a motor neuron?

Question 10. What type of neuron carries the efferent impulse toward an effector organ?

Question 11. True or false: The reflex response takes place before the brain is consciously aware of the stimulus.

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