PNS

Week 6 Study Guide

The Peripheral Nervous System Pt. I & Detecting Stimuli

  1. What is a generator potential? How does the strength of a stimulus affect the generator potential?



  1. If all action potentials are the same strength, how does the sensory neuron let the brain know about the strength of the stimulus? Provide a mechanistic explanation.

Gustation and Olfaction

  1. What types of receptors (broad classification) are responsible for detecting smell and taste? Are they of nervous or epithelial origin?

Hearing and Equilibrium

  1. Diagram how a sound wave (a mechanical force) is transmitted into an electrical signal at the auditory nerve. Be sure to include all organs involved in transmitting the message.

  2. What structures are responsible for detecting rotational acceleration of the head?

  3. What cell type is responsible for detecting this message?

  4. What structures are responsible for detecting head tilt?

  5. What cell type is responsible for detecting this message?

  6. Draw a diagram of how gravity is involved in detecting head tilt?

Vision

  1. Create a flow chart or draw a diagram of the eye to show the path that light takes to reach the retina. Include the following parts & functions: cornea, pupil, iris, lens, and retina.

  2. Where are photoreceptors located and how do the work? i.e. What happens to them in the dark (hyperpolarize or depolarize? Message sent to brain?) and what happens to them in the light (hyperpolarize or depolarize? Message sent to brain?)

  3. What are the structural and functional differences between rods & cones?

Autonomic Nervous System

  1. What is the overall function of the sympathetic division? List the response of targets, such as the heart, (smooth muscle of) respiratory airways, blood vessels in skeletal muscle, blood vessels to digestive tract/viscera, smooth muscle and secretions of digestive/urinary tract, iris of eye, sweat glands, and what happens to blood pressure and breathing rate.

  2. What are the overall functions of the parasympathetic division? What are some of the targets and how do they respond?

  3. Draw a simple diagram to compare and contrast the sympathetic and parasympathetic divisions and the pre- and post-ganglionic neurons of each. Include the following in your diagram:

  4. For preganglionic sympathetic neurons: Origin? Usually long or short? Branched? Cholinergic or adrenergic? Type of neurotransmitter they release? The type of receptor their neurotransmitter binds on postganglionic sympathetic neuron? Do they cause an excitatory or inhibitory effect on the postganglionic neuron?

  5. For postganglionic sympathetic neurons: Origin? Long or short? Cholinergic or adrenergic? Type of neurotransmitter they usually release? Know that this neurotransmitter can have excitatory or inhibitory effects depending on the receptor protein in the effector tissue.

  6. For preganglionic parasympathetic neurons: Origin? Long or short? Cholinergic or adrenergic? Type of neurotransmitter they release? Do they cause an excitatory or inhibitory effect on the postganglionic neuron?

  7. For preganglionic parasympathetic neurons: Origin? Long or short? Cholinergic or adrenergic? Type of neurotransmitter they release? What types of receptors do they bind on effectors? What is the response of the neurotransmitter binding receptors in the heart vs. digestive tract?

  8. Unlike most of the sympathetic nervous system which has a synaptic connection to its effectors, the adrenal gland is innervated through a monosynaptic connection. What is the physiological significance of this and what does sympathetic stimulation of the adrenal glands result in? You may use a diagram to explain your answer.

Voluntary Movement and Reflexes

  1.   What is the target of somatic motor neurons?

  2. Compare and contrast voluntary movement and reflexes when it comes to skeletal muscle.

  3. What is the functional purpose of reflexes?

  4. Why are reflexes are faster than voluntary movements?

  5. What is a reflex arc? Draw a simple reflex arc. Label the location and role of the sensory neuron, interneuron, and motor neuron.

  6. What is a monosynaptic reflex arc? What are examples?

  7. Explain in words and draw a diagram to illustrate the knee jerk reflex. Include the ligament, quadriceps muscle, spindle fibers, sensory neuron, motor neuron, spinal cord, synapse. Make sure the sensory neuron begins within the spindle apparatus and that the motor neuron terminates in the muscle fibers outside the spindle apparatus. What is meant by stretch and what is meant by contraction, and when do each occur during the reflex? Is this a monosynaptic or polysynaptic reflex? Explain.

  8. Be able to identify and distinguish the following classifications of neural reflexes:

    1. Response

    2. Development

    3. Processing site

    4. Complexity