Chapter 11 - Neural Tissue

Question 1

PNS

Answer 1

Includes all the neural tissue outside of cns. Has two divisions: sensory and motor.

Question 2

Motor division of PNS

Answer 2

Carries motor commands from cns to peripheral tissues. Includes two systems: somatic and autonomic.

Question 3

Sensory division of PNS

Answer 3

Brings information to the cns from receptors in peripheral tissues and organs.

Question 4

Somatic nervous system

Answer 4

Controls skeletal muscle contractions.

Question 5

Autonomic nervous system

Answer 5

Automatically regulates smooth muscle, cardiac muscle, glands, and adipose tissue.

Question 6

Somatic sensory receptors

Answer 6

Provide position, touch, pressure, pain, and temperature sensations.

Question 7

Special sensory receptors

Answer 7

Provide sensations of smell, taste, vision, balance, and hearing.

Question 8

Visceral sensory receptors

Answer 8

Monitor internal organs

Question 9

Dendrites

Answer 9

Receive stimuli from the environment or from other neurons. Highly branched.

Question 10

Cell body

Answer 10

Contains nucleus and other organelles.

Question 11

Axon

Answer 11

Carries information toward other cells.

Question 12

Axon hillock

Answer 12

Origin of the axon from main cell body of a neuron.

Question 13

Initial segment of axon

Answer 13

Where and action potential is initiated.

Question 14

Telodenria

Answer 14

Series of fine extensions from the end of the axon trunk.

Question 15

Synaptic terminals

Answer 15

Where the neuron communicates with other cells.

Question 16

Anaxonic neurons

Answer 16

Small and lack anatomical features that distinguish dendrites from axons.

Question 17

Bipolar neurons

Answer 17

Have two distinct processes - one dendritic process that branches extensively at its distal tip, and one axon - with the cell body between the two.

Question 18

Unipolar neurons

Answer 18

Dendrites and axon are continuous and the cell body lies off to one side.

Question 19

Multipolar neurons

Answer 19

Two or more dendrites and a single axon. Most common.

Question 20

CNS

Answer 20

Consists of brain and spinal cord. Integrating and processing sensory data and motor commands.

Question 21

Ganglion

Answer 21

Collection of neuron cell bodies in the PNS.

Question 22

Neuralgia

Answer 22

“Glial cells” support and protect neurons in the PNS and CNS. Abundant and diverse, make up about half the volume of the nervous system.

Question 23

Ependymal cells

Answer 23

Form a simple cuboidal to columnar epithelium known as the ependyma. Assist in producing and monitoring CSF.

Question 24

Ependyma

Answer 24

Lines a fluid filled passageway within the spinal cord and brain.

Question 25

Cerebrospinal fluid

Answer 25

Fills central canal of spine and surrounds the brain.

Question 26

Microglia

Answer 26

Removes cellular debris, wastes, and pathogens in the neural tissues.

Question 27

Astrocytes

Answer 27

Maintain the blood-brain barrier that isolates the CNS from the chemicals and hormones circulating in the blood.

Question 28

Oligodendrytes

Answer 28

Provide structural framework in CNS by stabilizing the positions of axons.

Question 29

Schwann cells

Answer 29

Only found in PNS. Form a sheath around peripheral axons. Outer membrane called neurolemma.

Question 30

Satellite cells

Answer 30

Surround neuron cell bodies in PNS. Regulate environment around neurons.

Question 31

Wallerian degeneration

Answer 31

Repair process of damaged axons in the PNS; often fails to restore full function.

Question 32

Membrane potential

Answer 32

Inside of plasma membrane has a slight negative charge with respect to the outside. Due to excess of positively charged ions outside the membrane and a slight excess of negatively charged ions and proteins inside the membrane.

Question 33

Graded potential

Answer 33

Temporary, localized change in resting potential produced by a stimulus. Change decreases with distance away from the stimulus.

Question 34

Action potential

Answer 34

An electrical event that involves one location on the membrane. Spreads along the surface of an axon toward terminals.

Question 35

Synaptic activity

Answer 35

Produces graded potentials in the plasma membrane of postsynaptic cells. Involves release of neurotransmitters such as ACh.

Question 36

Local current

Answer 36

Movement of positive charges parallel the the inner and outer membranes during a graded potential.

Question 37

Action potentials

Answer 37

Propagated changes in membrane potential that, once initiated, affect an entire excitable membrane.

Question 38

Threshold

Answer 38

Membrane potential at which voltage-gated sodium channels are opened in response to a powerful enough graded depolarization.

Question 39

Continuous propagation

Answer 39

Occurs along unmyelinated axons. Action potential appears to move along axolemma in tiny steps.

Question 40

Saltatory propagation

Answer 40

Occurs in myelinated axons. Local current skips the internode of an axon and depolarizes the closest node.

Question 41

Chemical synapses

Answer 41

Rely on neurotransmitter release. Depolarization of axon terminal is stimulus for neurotransmitter release.