Chapter 11

Question 0

Bipolar (neuron)

Answer 0

a type of neuron which has two extensions. Bipolar cells are specialized sensory neurons for the transmission of special senses. They are part of the sensory pathways for smell, sight, taste, hearing and vestibular functions. Found in the retina, inner ear and olfactory

Question 1

Multipolar (neuron)

Answer 1

a type of neuron that possesses a single (usually long) axon and many dendrites. Found in the brain and spinal cord

Question 2

Unipolar (Neuron)

Answer 2

a type of neuron in which only one protoplasmic process (neurite) extends from the cell body.

Question 3

Compare and contrast graded potentials and action potentials

GRADED POTENTIALS

Answer 3

Temporary, localized change in resting potential. Caused by stimulus.

LOCATION: dendrites/soma
DISTANCE: short
AMPLITUDE: various/graded
POTENTIAL: decays
STIMULUS: chemical (NT)
SUMMATION: temporal/spatial
DEGREE OF CHANGE: small

Question 4

compare and contrast graded potentials and action potentials

ACTION POTENTIALS

Answer 4

is an electrical impulse, it’s produced by graded potential, propagates along surface of axon to synapse

LOCATION: hillock/axon
DISTANCE: long
AMPLITUDE: always the same
POTENTIAL: no decay
STIMULUS: voltage (depolarization)
SUMMATION: no (all or none)
VOLTAGE CHANGE: +>-
DEGREE OF CHANGE: Large

Question 5

Absolute refractory period

Answer 5

incapable of generating another action potential

Question 6

Relative Refractory Period

Answer 6

Requires greater than normal amount of stimulation to generate another action potential

Question 7

Define Neuron

Answer 7

is an electrically excitable cell that processes and transmits information through electrical and chemical signals.

Question 8

Soma

Answer 8

Cell body, bulbous end of a neuron, containing the nucleus.

Question 9

Dendrites

Answer 9

branched projections of a neuron that act to propagate the electrochemical stimulation received from other neural cells to the cell body.

Question 10

Axon

Answer 10

also known as a nerve fibre, is a long, slender projection of a nerve cell or neuron, that typically conducts electrical impulses away from the neurons cell body. the function of the axon is to transmit info to different neurons, muscles and glands.

Question 11

Define resting membrane potential

Answer 11

the resting membrane potential of a neuron is about -70mV (mV=milivolt). This means that the inside of the neuron is 70 mV less than the outside. At rest, there are relatively more sodium ions outside the neuron and more potassium ions inside that neuron.

Question 12

Define synapse

Answer 12

a structure that permits a neuron to pass an electrical or chemical signal to another cell

Question 13

Electiral synapse

Answer 13

neurons that are electrically coupled via protein channels (gap junctions) and allow for the direct transfer of ions. only in brain, eyes and cardiac.

Question 14

Chemical synapses

Answer 14

specialized for the release and reception of chemical neurotransmitters. make up the bulk of synapses.

Question 15

Differentiate between a nerve and a tract

Answer 15

Nerve: an enclosed, cable-like bundle of axons in the PNS. a nerve provides a common pathway for the electrochemical nerve impulses that are transmitted along each of the axons to peripheral organs.

Tracts:Connects one part of the nervous system with another and usually consists of bundles of elongated, myelin-insulated neurons, known collectively as white matter.

Question 16

Differentiate between a nucleus and a ganglion

Answer 16

nucleus: collection of nerve bodies, found in the CNS

Ganglion: is a nerve cell cluster located in the PNS

Question 17

Explain how action potentials are generated

Answer 17

as an action potential travels down the axon, there is a change in polarity across the membrane. The Na+ and K+ gated ion channels open and close as the membrane reaches the threshold potential, in response to a signal from another neuron.

Question 18

the importance of myelin sheath

Answer 18

the gaps formed between myelin sheath cells long the axons are called Nodes of Ranvier. Since fat serves as a good insulator, the myelin sheaths speed the rate of transmission of an electrical impulse along the axon.

Question 19

How are myelin sheaths formed?

Answer 19

the sheath is formed by the cell membranes of glial cells (Schwann cells in the PNS and Oligodendroglia in the CNS)

Question 20

Basic functions of the nervous system

Answer 20

• Sensory neurons receive info from sensory receptors
• interneurons transfer and interpret impulses (integration)
• motor neurons send appropriate impulses/ instructions to the muscles and glands

Question 21

explain the structural and functional divisions of the nervous system

Answer 21

CNS-brain and spinal cord (12 cranial nerves) (31 spinal nerves)
PNS- Outer regions of body

Question 22

sympathetic

Answer 22

fight or flight

Question 23

parasympathetic

Answer 23

rest and digest

Question 24

Astorcytes (neuroglia)

Answer 24

regulate the chemical enviornment, helps form and maintain the blood-brain barrier. Large cell bodies with many processes. Repairs damaged neural tissue. CNS

Question 25

Microglia (neuroglia)

Answer 25

CNS cells that monitor health and preform immune functions. Smallest and least numerous neuroglia with many fine-branched processes. Clean up waste

Question 26

Ependymal Cells

Answer 26

Cells with highly branched processes; contact neuroglia directly. line central canal of spinal cord and ventricles of brain. CNS

Question 27

Oliodendrocytes (Neuroglia)

Answer 27

CNS glial cells that wrap around neurons forming myelin sheaths (MS is loss of this). Smaller cell bodies with few processes.

Question 28

Satellite Cells (neuroglia)

Answer 28

PNS located, function unknown. surround cell body in the neuron. regulates oxygen, carbon dioxide and nutrient levels around the neuron.

Question 29

Schwann cells (neuroglia)

Answer 29

PNS, forms myelin sheath. Surrounds all axons in the PNS. They are the insulators.

Question 30

Saltatory conduction

Answer 30

the propagation of action potentials along myelinated axons from one node of Ranvier to the next node, increasing the conduction velocity of action potentials.

Question 31

Excitatory Postsynaptic potentials

Answer 31

is a postsynaptic potential that makes the neuron more likely to fire an action potential. This temporary depolarization of postsynaptic membrane potential caused by the flow of positively charge ions into the postsynaptic cells, is a result of opening ligand-gated ion channels.

Question 32

inhibitory postsynaptic potentials

Answer 32

is a kind of synaptic potential that makes a postsynaptic neuron less likely to generate an action potential. The opposite of an inhibitory postsynaptic potential is an excitatory postsynaptic potential, which is a synaptic potential that makes a a postsynaptic neuron more likely to generate and action potential.

Question 33

Neurotransmitter

Answer 33

are endogenous chemicals that transmit signals across a synapse from one neuron to another “target” neuron. Neurotransmitters are released from synaptic vesicles in synapses into the synaptic cleft, where they are received by receptors on other synapses.

Question 34

Acetylcholine

Answer 34

one of the many neurotransmitters in the autonomic nervouse system (ANS). It acts on both the PNS and the CNS and is the only neurotransmitter used in the motor division of the somatic nervous system. activates skeletal muscles in the PNS.

Question 35

synapse

Answer 35

area where a neuron communicates with another cell

Question 36

Presynaptic cell

Answer 36

sends message

Question 37

synaptic cleft

Answer 37

the small gap that separates the presynaptic membrane and the postsynaptic membrane

Question 38

postsynaptic cell

Answer 38

receives the message

Question 39

synaptic knob

Answer 39

the expanded area of the axon of the presynaptic neuron. containes synaptic vesicles of neurotransmitters (chemical messengers), they will bind to receptors on the postsynaptic membrane