Chapter 2: Cells and Structures -- The Anatomy of the Nervous System

Neurons have 4 Functional Zones

1. Input 2. Integration 3. Conduction 4. Output

The Cranial Nerves

1. Olfactory 2. Optic 3. Oculomotor 4. Trochlear 5. Trigeminal 6. Abducens 7. Facial 8. Vestibulocochlear 9. Glossopharyngeal 10. Vagus 11. Spinal Accessory 12. Hypoglossal

How Many Cranial Nerves are There?

12

Neurons have 4 Functional Zones: Conduction

A single axon (or nerve fiber) conducts output info away from the cell body as an electrical impluse

Which statement about glial cells is false? A. They are found outside the nervous system. B. They are important for providing structural support for neurons. C. They regulate the chemical content of the extracellular space of surrounding neurons. D. Some types of glia are responsible for myelinating axons.

A. They are found outside the nervous system.

Neurons are very noisy—whether or not they are currently firing is probabilistic. A. True B. False

A. True

True or False: Some neurons send axons all the way across the brain. A. True B. False

A. True

Sensory Neurons ____ A. collect info from a single source B. pass information on to command muscles to move C. collect information from many sources

A. collect info from a single source

When you swallow, you are using the _____ cranial nerve. A. glossopharyngeal B. olfactory C. vestibulocochlear D. optic

A. glossopharyngeal

Making eye movements requires the _____ cranial nerve. A. oculomotor B. olfactory C. glossopharyngeal D. trigeminal

A. oculomotor

Match the Neuron to its Description A. Motor B. Sensory C. Interneuron D. Multipolar E. Bipolar F. Unipolar 1. a neuron with one axon and many branching dendrites 2. a neuron that brings information from the senses 3. a neuron that connects other neurons (not sensory or motor) 4. a neuron that has a single axon one end and one dendrite on the other side 5. a neuron that activates neurons with messages from the brain 6. a neuron that has a single branch that extends in two directions

A.5 B. 2 C. 3 D. 1 E. 4 F. 6

Two Other Types of Glial Cells

Astrocytes Microglial Cells

Neurons have 4 Functional Zones: Output

Axon terminals at the end of the axon communicate activity to other cells

Which of the following statements is TRUE? A. Schwann cells are present only in the developing organism and thus have nothing to do with regeneration. B. In the peripheral nervous system Schwann cells serve as signposts to guide axons to their appropriate end points. C. In the central nervous system Schwann cells serve as guideposts to show axons where to terminate when regeneration occurs. D. Schwann cells cannot help damaged axons, because neither nervous system can regenerate.

B. In the peripheral nervous system Schwann cells serve as signposts to guide axons to their appropriate end points.

The presynaptic terminal is located on the ____________ and the postsynaptic region of the synapse is typically located on a(n) ___________. A. output zone; input zone B. axon terminal; dendrite or dendritic spine C. dendrite or dendritic spine; axon terminal D. soma; axon terminal

B. axon terminal; dendrite or dendritic spine

This figure shows three neurons, Neurons A & C are excitatory and Neuron B is inhibitory. Neuron A synapses on Neuron B, and Neuron B synapses on Neuron C. A->B->C What happens to Neuron B if the firing rate of Neuron A increases? A. it doesn't change B. it increases C. Not enough information D. it decreases E. None of these

B. it increases

Which of the following structures are typically found within the axon (presynaptic) terminal? A. the nucleolus and synaptic vesicles B. mitochondria and synaptic vesicles C. myelin and mitochondria D. the nucleolus and endoplasmic reticulum

B. mitochondria and synaptic vesicles

Damage to efferent cranial nerves would result in _______ impairments; damage to afferent cranial nerves would result in _______ impairments. A. sympathetic; parasympathetic B. motor; sensory C. sensory; motor D. parasympathetic; sympathetic

B. motor; sensory

The uncovered section of the axon between two segments of myelin is known as the _______. A. axon terminal B. node of Ranvier C. axon hillock D. collateral

B. node of Ranvier

Motor Neurons _____ A. collect info from a single source B. pass information on to command muscles to move C. collect information from many sources

B. pass information on to command muscles to move

What is another word for presynaptic terminal? May be more than 1 answer A. axon B. synaptic bouton C. dendrite D. postsynaptic terminal E. axon terminal

B. synaptic bouton E. axon terminal

Which glial cells interact with blood vessels? A. Stellate cells B. Microglial cells C. Astrocytes D. Oligodendrocytes

C. Astrocytes

Which pathway represents the most common sequence of information flow through a neuron? A. Dendrite → cell body → axon → axon hillock B. Cell body → axon → axon hillock → axon terminal C. Dendrite → cell body → axon hillock → axon D. Dendrite → axon terminal → cell body → axon

C. Dendrite → cell body → axon hillock → axon

Which type of cell is responsible for myelination within the central nervous system? A. Microglial cells B. Schwann cells C. Oligodendrocytes D. Astrocytes

C. Oligodendrocytes

The output zone of the neuron is the A. dendrites B. soma C. axon terminal D. axon

C. axon terminal

Interneurons _____ A. collect info from a single source B. pass information on to command muscles to move C. collect information from many sources

C. collect information from many sources

The term for a neurotransmitter moving out of the synapse is: A. transportation B. degradation C. diffusion D. reuptake

C. diffusion

Cranial Nerves and Function

CN I -- Sensory CN II -- Sensory CN III -- Motor CN IV -- Motor CN V -- Sensory + Motor CN VI -- Motor CN VII -- Sensory + Motor CN VIII -- Sensory CN IX -- Sensory + Motor CN X -- Sensory + Motor CN XI -- Motor CN XII -- Motor

Axon Hillock

Cone shaped region of an axon where it joins the cell body. Converts input into electrical signals that travel down the axon and innervate target cells

The two basic building blocks of the nervous system are neurons and _________. A. neurotransmitters B. dendrites C. proteins D. glial cells

D. glial cells

Neurotransmission typically occurs between which two sites? A. somas and axons B. dendrites and postsynaptic targets C. axons and axon terminals D. presynaptic terminals and postsynaptic targets

D. presynaptic terminals and postsynaptic targets

Moving your head and neck requires signals carried by the _____ cranial nerve. A. glossopharyngeal B. oculomotor C. optic D. spinal accessory

D. spinal accessory

Neurons have 4 Functional Zones: Input

Dendrites receive info from other cells or the environment

This figure shows three neurons, Neurons A & C are excitatory and Neuron B is inhibitory. How would you describe this type of neural connection?Neuron A synapses on Neuron B, and Neuron B synapses on Neuron C. A->B->C A. feedback inhibition B. convergent C. divergent D. None of these E. lateral inhibition F. feedforward inhibiiton

F. feedforward inhibiiton

Cranial Nerve: Trigeminal (V)

Face, sinuses, teeth Sensory

Different Shapes of Neurons Reflect their...

Function

Cranial Nerve: Vagus (X)

Information from internal organs Sensory

Cranial Nerve: Vestibulocochlear (VIII)

Inner ear; hearing and balance Sensory

Neurons with Different Shapes

Motor Sensory Interneurons

Neurons are also classified by three general types:

Multipolar Bipolar Unipolar

Cranial Nerves: Oculomotor (III), Trochlear (IV), and Abducens (VI)

Muscles that move the eyes Motor

Cranial Nerve: Spinal Accesory (XI)

Neck Muscles Motor

Which Cranial Nerves are Motor?

Oculomotor (III) Trochlear (IV) Abducens (VI) Spinal Accessory (XI) Hypoglossal (XII)

Which Cranial Nerves are Sensory?

Olfactory (I) Optic (II) Trigeminal (V) Facial (VII) Vestibulocochlear (VIII) Glossopharyngeal (IX) Vagus (X)

Types of Glial Cells the Wrap Around Axons to Provide the Myelin

Oligodendrocytes Schwann Cells

Synapses have three components:

Presynaptic membrane Postsynaptic membrane Synaptic cleft

Cranial Nerve: Olfactory (I)

Smell Sensory

Cranial Nerve: Glossopharyngeal (IX)

Taste and other mouth sensations Sensory

Neurons have 4 Functional Zones: Integration

The cell body (or soma) integrates the info it received from the dendrites

Cranial Nerve: Hypoglossal (XII)

Tongue muscles Motor

Cranial Nerve: Facial (VII)

Tongue, soft palate Sensory

Cranial Nerve: Optic (II)

Vision Sensory

Axon Collateral

a branch of axon that also ends in terminals

Neurons

a nerve cell; the basic building block of the nervous system

Unipolar Neurons

a single extension branches in two directions, forming an input zone and an output zone

Glial Cells

assist neuronal activity by providing raw materials, chemical signals, and structure and also participate in info processing

Oligodendrocytes

form the myelin sheaths in the brain and spinal cord (in CNS) glial cell

Nodes of Ranvier

gaps between sections of myelin where the axon is exposed high concentration of Na+ channels

Interneurons Size/Shape

have tiny axons and analyze input form one set of neurons and communicate with others

Sensory Neurons Size/Shape

have various shapes that best respond to specific environmental stimuli, such as light, odor, or touch

Neurotransmitter Receptors

in the postsynaptic membrane are specialized proteins that react to neurotransmitter molecules

Motor Neurons Size/Shape

large, have long axons, and stimulate muscles

Motor Neurons

neurons that carry outgoing information from the brain and spinal cord to the muscles and glands

Sensory Neurons

neurons that receive information from the external world and convey this information to the brain via the spinal cord

Interneurons

neurons within the brain and spinal cord (CNS) that communicate internally and intervene between the sensory inputs and motor outputs

Presynaptic Membrane

on the axon terminal of the presynaptic neuron

Postsynaptic Membrane

on the dendrite or cell body of the postsynaptic neuron

Multipolar Neurons

one axon, many dendrites most common

Bipolar Neurons

one axon, one dendrite

Schwann Cells

provide myelin to neurons outside the brain and spinal cord (in PNS) glial cell

Synaptic Vesicles

small spheres in presynaptic axon terminals that contain a neurotransmitter

Astrocytes

star-shaped cells with many processes that stretch around and between neurons and, sometimes, blood vessels secrete chemicals and help form the outer membrane around the brain glial cell

Axonal Transport

the bidirectional movement of material within an axon

Synaptic Cleft

the gap that separates the membranes

Microglial Cells (microglia)

tiny, mobile cells that remove debris from injured or dead cells glial cell