Organismal And Ecological Biology Chapter 41 Test 1

Front 1

What is the flow of information through the Nervous system

Back 1

Stimulus -->Reception --> Transmission --> Integration --> CNS --> Transmission --> Response

Front 2

What is the CNS

Back 2

CNS stands for Central Nervous System and is made up of the nerves in the spine and brain

Front 3

What is the PNS

Back 3

PNS stands for Peripheral nervous system and this is comprised of all other nerves in the body

Front 4

What are the types of Cells in the Nervous System?

Back 4

1. Neurons

~ Afferent or sensory

~ Efferent

~ Interneurons

Front 5

What are electrical signals that are produced by neurons called?

Back 5

Nerve Impulses or Action potentials

Front 6

What is the Cell body?

Back 6

Contains the nucleus, most of the cytoplasm, and most of the organelles

Front 7

What are the two types of cytoplasmic processes and what do they do?

Back 7

1. Dendrites --> receive stimuli and conduct them towards the cell body

2. Axon --> conduct nerve impulses away from the cell body to another neuron or to a muscle or gland

Front 8

What are Axon Collaterals?

Back 8

when an axon divides, it may form branches called axon collaterals

Front 9

What are Synaptic Terminals?

Back 9

The branches that are formed at the end of an axon

Front 10

What are Neurotransmitters?

Back 10

Synaptic terminals release them and they transmit signals from one neuron to another

Front 11

What is a synapse?

Back 11

The junction between a synaptic terminal and another neuron

Front 12

What are nodes of Ranvier?

Back 12

Gaps in the myelin sheaths (points in the axon not insulated with myelin)

Front 13

What is an Axon Hillock?

Back 13

Conical region where the cell body connects to the axon. Site where synaptic inputs are summated before an action potential is transmitted to the axon.

Front 14

What are axons surrounded by?

Back 14

special glial cells (Oligodendrocytes or Schwann cells) that form an insulating myelin sheath around the axon

Front 15

What are bundles of axons called both in the PNS and the CNS?

Back 15

Nerves (PNS)

Tracts (CNS)

Front 16

What are Aggregations of nerve cell bodies called in both the CNS and PNS?

Back 16

Ganglia (PNS)

Nuclei (CNS)

Front 17

What are the four types of glial cells found in the vertebrate CNS?

Back 17

1. Astrocytes

2. Oligodendrocytes

3. Ependymal Cells

4. Microglia

Front 18

What are Astrocytes

Back 18

1. Star-shaped glial cells that provide physical support for neurons

2. provide neurons with nutrients

3. Form tight junctions in the blood-brain barrier

Front 19

What are Oligondendrocytes?

Back 19

Glial cells that form insulating myelin sheaths around neurons in the CNS

~ Speed transmission of neuron impulses

Front 20

What are Ependymal cells?

Back 20

1. Ciliated glial cells that line internal cavities in the CNS

2. Help produce and circulate cerebrospinal fluid that bathes the brain and spinal cord of vertebrates

3. Recent research suggests that ependymal cells might function as neural stem cells

Front 21

What are Microglia?

Back 21

1. Specialized CNS macrophages

~ respond to signals from neurons; important in mediating responses to injury or disease

2. When the brain is injured or infected, microglia move to the affected area and remove bacteria and cell debris

3. Microglia release signaling molecules that mediate inflammation

Front 22

How are Ion-Specific Channels opened or closed?

Back 22

These channels can be opened or closed (they are gated) in response to:

1. a change in voltage across the membrane

2. a chemical (we call this a neurotransmitter)

Front 23

What are Ion-specific Channels?

Back 23

the neuron membrane contains integral, transmembrane proteins that serve as channels for specific ions (charged molecules)

Front 24

What are Ligand-Gated Ion Channels?

Back 24

When a ligand binds to a specific receptor it opens up the channel and allows Ions to move through

Front 25

What does it mean when a membrane is polarized?

Back 25

One side has a different charge than the other

Front 26

what is membrane potential?

Back 26

The difference in charge across the plasma membrane

Front 27

What is resting potential?

Back 27

When the membrane potential of a neuron is at rest (not firing)

Front 28

What are the two things that determine resting potential?

Back 28

1. Difference in concentration of ions in and out of the cell

2. Selective permeability of the plasma membrane to these ions (they only allow certain ones to pass through)

Front 29

What is the ratio for sodium and potassium passing through the pump?

Back 29

Sodium 3 potassium 2

Front 30

Which ion is more permeable through a membrane?

Back 30

Potassium

Front 31

What is Graded potential?

Back 31

1. Change in membrane potential

2. Local response that varies in magnitude depending on the strength of the applied stimulus

3. Fades out within a few mm of its point of origin

Front 32

What is a depolarized membrane?

Back 32

When the membrane potential to becomes less negative than the resting potential

Front 33

What is hyperpolarized membrane?

Back 33

Membrane potential becomes more negative than the resting potential

Front 34

What is an Action Potential?

Back 34

1. Wave of depolarization that moves down the axon

2. When the threshold level is reached, voltage-activated ion channels open, allowing sodium to flow into the neuron

3. Action potential is generated

Front 35

What does it mean that an action potential is an all-or-none response

Back 35

1. No variation exists in the strength of a single impulse

2. Membrane potential either exceeds threshold level, leading to transmission of an action potential, or it does not

Front 36

Describe what is happening at each number

Back 36

1. Resting potential

2. Depolarization phase

3. Potassium channels open

4. Repolarization phase

5. undershoot

Front 37

What happens behind an action potential as it moves down the axon?

Back 37

repolarization occurs

Front 38

What is the Refractory period?

Back 38

Time when it cannot transmit another action potential

Front 39

What are the two different types of Conduction?

Back 39

1. Continuous

2. Saltatory

Front 40

What is Continuous conduction?

Back 40

1. Takes place in unmyelinated neurons

2. Involves the entire axon plasma membrane

Front 41

What is saltatory conduction?

Back 41

1. More rapid than continuous conduction

2. Takes place in myelinated neurons

3. Depolarization skips along the axon from one nodes of Ranvier to the next.