Chapter 7

Front 1

What is Nervous Tissue?

Back 1

-Nervous tissue functions to conduct messages throughout the body.

-When nerve cells are stimulated, an electrical signal quickly travels through the nerve cell to the nerve ending, triggering events

Front 2

What does the Nervous System include?

Back 2

Tissues and Sense Organs

Front 3

What is the function of the Nervous System?

Back 3

 Nervous system functions to:

 Senses environment – receives information from both outside and inside the body

 Processes the information it receives

 Respond to information – sends out orders

Front 4

What are the two parts of the Nervous System?

Back 4

1. Central Nervous System (CNS)

 Brain and Spinal Cord

2. Peripheral Nervous System (PNS)

 Nervous tissue outside brain and spinal cord Sense organs

Front 5

What does the Central Nervous System (CNS) include?

Back 5

 Brain and Spinal Cord

Front 6

What does the Peripheral Nervous System (PNS) include?

Back 6

 Nervous tissue outside brain and spinal cord  Sense organs

Front 7

What are the two different types of Nervous Tissue Cells?

Back 7

Two types of nervous tissue cells

 Neurons – the cells that are responsible for transmitting messages

 Neuroglial cells – cells that support the neurons

Front 8

What are the 3 different types of Neuroglial cells?

Back 8

 Microglia – immune system cells, engulf bacteria and cellular debris

 Astrocytes – provide nutrients to neurons

 Oligodenrocytes and Schwann cells – formmyelin sheaths

Front 9

What is the function of Neuroglial Cell, Microflia?

Back 9

Immune system cells, engulf bacteria and cellular debris

Front 10

What is the function of Neuroglial Cell, Astrocytes?

Back 10

Provide nutrients to neurons

Front 11

What is the function of Neuroglial Cell,Oligodenrocytes and Schwann cells ?

Back 11

Form myelin sheath.

Front 12

Where is the PNS and CNS located?

Back 12

Front 13

What are the parts of a Neuron?

Back 13

 Cell body – contains the nucleus, main body of cell

 Dendrites – projections from the cell body that carry messages to the cell body

 Axons – one large projection that carry messages away from the cell body

Front 14

What is the Cell Body of a Neuron?

Back 14

Contains the nucleus, main body of cell

Front 15

What are the Dendrites of a Neuron?

Back 15

Projections from the cell body that carry messages to the cell body

Front 16

What are the Axons of a Neuron?

Back 16

One large projection that carry messages away from the cell body

Front 17

What do Neurons in the Peripheral Nervous System do?

Back 17

Neurons in the PNS are either carrying messages to or from the CNS

Front 18

Within the PNS, what are Afferent Neurons?

Where is it located?

Back 18

- Afferent = Sensory neurons =

Neurons carrying messages to the CNS

-The efferent or motor neuron cell bodies are located in the gray matter of the spinal cord. Their axons leave the CNS and go to the skeletal muscles

Front 19

Within the PNS, what are Efferent Neurons? Where is it located?

Back 19

-Efferent = Motor neurons =

Neurons carrying messages from the CNS

-The afferent or sensory neuron cell bodies are located in dorsal root ganglion.

Front 20

Where are inter-neurons located? What is their Function?

Back 20

-An Interneuron is an association neuron.
- Located between sensory and motorneurons within the CNS

- Interneurons integrate and interpret sensory signals

Front 21

The cell bodies of these neurons are located in the dorsalroot ganglion

Back 21

Afferent or Sensory Neurons

Front 22

These neuroglial cells provide nutrients to neurons

Back 22

Astrocytes

Front 23

These are projections of the neuron cell body that carrymessages to the cell body

Back 23

Dendrites

Front 24

Which of the following type of neuron would alert the brainthat you had touched a hot object?

Back 24

Afferent Neuron

Front 25

What are Myelinated Neurons?

Back 25

- Neurons that have axons covered with neuroglial cells that contain the protein myelin are called myelinated neurons

- Myelinated neurons are able to carry messages faster than non-myelinated neurons

Front 26

What is Myelin?

Back 26

A mixture of proteins and phospholipids forming a whitish insulating sheath around many nerve fibers, increasing the speed at which impulses are conducted.

Front 27

What is a Myelin Sheath?

Back 27

An insulating layer around axons that carry nerve impulses over relatively long distances that is composed of glial cells.

Front 28

What are the functions of Myelin Sheaths?

Back 28

1. The main benefit of myelin sheaths is that myelinated neurons are able to carry messages faster than non-myelinated neurons

2. Myelin sheaths from Schwann cells also help regenerate injured PNS neuron axons

Front 29

What are the two types of cells that Myelinated Neurons?

Back 29

 Schwann cells and Oligodendrocytes are wrapped around neuronal axons

Front 30

What is the function and location Of Schwann Cells?

Back 30

-Cells that Myelinate Neurons

-They are located in the PNS

Front 31

What is the function and location of Oligodendrocytes?

Back 31

-Cells that Myelinate Neurons

-They are located in the CNS

Front 32

What are Nodes of Ranvier?

Back 32

 Nodes of Ranvier are spaces on the axon between the glial cells

Front 33

What is the cause and effects of multiple sclerosis?

Back 33

 Caused by the destruction of the myelin sheath that surrounds axons found in the CNS

 Can result in paralysis and loss of sensation, including loss of vision

Front 34

What are the parts of a Nerve?

Back 34

Nerve contain Neuron axons are bundled together

 These bundles contain

 Axons

 Blood vessels

 Connective tissue

Front 35

How can an Ions pass through a membrane?

Back 35

Facilitated Diffusion and Active Transport

Front 36

An Ion is an atom that has gained or lost a(n)_____________?

Back 36

Electron

Front 37

What is a Nerve Impulse?

Back 37

A nerve impulse, or action potential, involvessodium ions (Na+) and potassium ions (K+)that cross the cell membrane through the ion channels

 Each ion channel is designed to allow only certain ions to pass through

Front 38

What is a Membrane Potential?

Back 38

The difference in charge between the inside and outside of the neuron

Front 39

What is a "Resting Neuron"?

Back 39

A neuron that is not conducting a message

Front 40

When a Neuron is resting, what ions are there more of inside and outside of the cell?

What is the charge inside and outside of the cell?

Back 40

 When a neuron is resting there is more sodium (Na+) outside the neuron cell and more potassium (K+) inside the cell
 The inside of the cell has a negative charge compared to the outside the cell

Front 41

How does a neuron maintain a resting membrane potential?

Back 41

To maintain this resting membrane potentialthe neuron pumps Na+ out of the cell and K+into the cell.
The transport proteins take 3 Na+ ions out forevery 2 K+ ions into the cell = Na+/K+ pump
This is Active Transport – requiring ATP

Front 42

What ions enter the neuron during Depolarization of an Action Potential?

Back 42

Sodium ions (Na+)enter the axon, causing the inside of the neuron tobecome Positively charged

Front 43

What ions leave the Neuron during Repolarization of an Action Potential?

Back 43

Potassiumions (K+) leave the axon, causing the inside of the Neuron to become Negatively charged.

Front 44

-What ions enter and the leave the neuron duringthe depolarization and repolarization steps ofaction potential?

-What is the relative charge of theinside vs the outside of the neuron during theseevents.

(Know these events in order)

Back 44

1) The axon is depolarized when voltage gatedsodium ion channels open and Na+ comesrushing in, causing the inside of the neuron tobecome positively charged.
2) The axon is repolarized when voltage gatedpotassium ion channels open up and allow K+to go out of the axon.
- This returns the membrane potential to benegative on the inside of the neuron
-The action potential travels down the axon

Front 45

What happens after the Action Potential Occurs?

Back 45

After the action potential, the sodiumpotassium pump restores the originalconditions by pumping sodium (Na+) out ofthe cell and potassium (K+) back into the cell (Resting Potential).

Front 46

What is an Action Potential?

Back 46

It is an all or nothing response – if it is nota great enough stimulation the channelswon’t open. The level of the actionpotential is always the same.

Front 47

What is a Refractory Period?

Back 47

The direction is always one way down theaxon. The sodium channels areinactivated for awhile after the actionpotential passes = refractory period.

Front 48

When a neuron is resting, sodium ions have a greaterconcentration___________?

Back 48

Outside the cell

Front 49

When a neuron is depolarizing, which ions come into theneuron___________?

Back 49

Sodium (Na+) ions.

Front 50

When a neuron is depolarizing, the inside of the neuron cellbecomes_____________?

Back 50

Positively Charged

Front 51

What is a Synapse?

Back 51

The junction between two neurons orbetween a neuron and a muscle is called asynapse

Front 52

What are the components of a Synapse?

Back 52

1. Presynaptic neuron is the transmittingneuron2. Postsynaptic neuron is the receiving neuronor the muscle
3. And the gap in between them = synapticcleft

Front 53

What is a Presynaptic neuron?

Back 53

Presynaptic neuron has synapticvesicles that contain neurotransmitters. This is the Transmitting Neuron.

Front 54

What is a Postsynaptic Neuron?

Back 54

The receiving neuronor the muscle

Front 55

What is the Synaptic Cleft?

Back 55

The gap in between the Presynaptic and Postsynaptic Neurons.

Front 56

What are the steps in the Snaptic Transmission?

Back 56

1. The action potential gets to the end of thepresynaptic axon
2. The action potential triggers Ca2+ to enterthe presynaptic axon terminal
3. The Ca2+ triggers synaptic vesicles locatedat the axon terminal to merge with theneural membrane
4. The synaptic vesicles release theneurotransmitters into the synaptic cleft
5. These neurotransmitters travel across thesynaptic cleft to the postsynaptic neuron(or the muscle)
6. Neurotransmitter binds to receptors on thepostsynaptic neuron (or muscle)
7. These receptors are ligand gated sodium ionchannels which allow Na+ to enter thepostsynaptic neuron (or muscle) and triggersan action potential in the postsynaptic neuron(or muscle contraction)
8. Once the neurotransmitters are released theyneed to be destroyed or contained quickly orthey will continue to stimulate the nerve

Front 57

What is acetylcholine, where is it found, and what effectdoes it have on humans?

Back 57

 Acetylcholine acts as a neurotransmitter in both the PNS and the CNS/
 It causes voluntary muscles to contract
(I will voluntarily take "A seat")

Front 58

How is Acetylcholine removed from the Synaptic Cleft?

Back 58

By a specialized enzyme for inactivation right in the synaptic cleft called acetylcholinesterase

Front 59

What is the cause and effect of Myasthenia gravis

Back 59

Myasthenia gravis is an autoimmunedisease that attacks the acetylcholinereceptors, resulting in reduced musclestrength

Front 60

What is an Ion?

Back 60

An atom or group of atoms that carries an electric charge resulting from the loss or gain of an electron.

Front 61

What is an Ion Channel?

Back 61

Each ion channel is designed to allow only certain ions to pass through.

Front 62

What is the Sodium Potassium Pump?

Back 62

A molecular mechanisms in the plasma membrane that uses cellular energy in the form of ATP to pump ions against their concentration gradients.

(For every 3 Sodium Ions the pump ejects, it brings in 2 Potassium Ions.

Front 63

What is a Synapse?

Back 63

The site of communication between a neuron and another cell, such as another neuron or a muscle.

Front 64

What is a Synaptic Vesicle?

Back 64

A membranous sac containing molecules of a neurotransmitter. Synaptic Vesicles are located in the synaptic knobs of axon endings, and they release their contents when an action potential reaches a synaptic knob.

Front 65

What are Neurotransmitters?

Back 65

A chemical released from the axon tip of a Neuron that affects the activity of another cell (usually a nerve, muscle, or gland cell) by alerting the electrochemical signals called action or nerve impulses.

Front 66

What does Stimulate mean?

Back 66

Raised levels of physiological or nervous activity in (the body or any biological system).

Front 67

What does Inhibit mean?

Back 67

Hinder, restrain, or prevent (an action or process).