Nervous System

Question 1

Neurons

Answer 1

Specialized cells capable of transmitting electrical impulses and then translating those into chemical signals

Question 2

Dendrites

Answer 2

Part of the Neuron:

Receive incoming messages from other cells

Question 3

Cell Body (Soma)

Answer 3

Part of the Neuron:

Where nucleus, ER and ribosomes are located

Question 4

Axon Hillock

Answer 4

Part of the Neuron:

Integrates incoming signals and plays and important role in action potentials

Question 5

Action Potentials

Answer 5

Part of the Neuron:

Transmission of all-or-nothing electrical impulses down the axon

Question 6

Axon

Answer 6

Part of the Neuron:

Long appendage

Question 7

Myelin

Answer 7

Part of the Neuron:

Insulates the nerve fibers to prevent signal loss or crossing of signals

Question 8

Myelin Sheath

Answer 8

Part of the Neuron:

Maintain electrical signal within one neuron and increases speed of conduction in the axon

Question 9

Schwann Cells

Answer 9

Glial Cell: Part of the Neuron:

Produce myelin around axons in peripheral nervous system

Question 10

Oligodendrocytes

Answer 10

Glial Cell:

Produce myelin around the axons in central nervous system

Question 11

Nodes of Ranvier

Answer 11

Part of the Neuron:

Small breaks in the myelin sheath which expose the axon membrane and are critical for rapid signal conduction

Question 12

Nerve Terminals (Synaptic Bouton)

Answer 12

Part of the Neuron:

Maximize neurotransmission to the next neuron and ensure proper release of neurotransmitters

Question 13

Synaptic Cleft

Answer 13

Small space between neurons

Question 14

Synapse

Answer 14

Nerve Terminal + Synaptic Cleft + Post Synaptic Membrane

• Where neurotransmitters release from axon terminal transverse the synaptic cleft and bind to receptors

Question 15

Nerves

Answer 15

Multiple neurons bundled together - can be sensory, motor or mixed (depending on the type of info. they carry)

Question 16

Tracts

Answer 16

Axons bundled together BUT can carry only one type of information

Question 17

Astrocyte

Answer 17

Glial Cell:
Nourish neurons and form the blood brain barrier which controls the transmission of solutes from the blood stream into the nervous tissue

Question 18

Ependymal Cells

Answer 18

Glial Cell:
Line the ventricles of the brain and produce the cerebrospinal fluid which physically supports the brain and serves as a shock absorber

Question 19

Microglia

Answer 19

Glial Cell:

Phagocytic cells that ingest and breakdown waste products and pathogens in the central nervous system

Question 20

Glial Cells

Answer 20

• Astrocytes
• Schwann Cells
• Oligodendrocyte
• Microglia
• Ependymal Cells

Question 21

Resting Membrane Potential

Answer 21

Potential difference between the inside of the neuron and the extracellular space (about -70mV) with inside of the neuron being negative

Question 22

Na+ / K+ ATPase

Answer 22

Restore [ ] gradient transporting 3Na+ out of the cell for every 2K+ into the cell at the expense of 1 ATP.

Question 23

Depolarization

Answer 23

Caused by excitatory input (if enough to reach the threshold causes an action potential) to raise membrane potential (mV)

Question 24

Hyperpolarization

Answer 24

Caused by inhibitory input lowering the membrane potential

Question 25

Summation

Answer 25

Additive effects of multiple signals

Question 26

Temporal Signals

Answer 26

Type of Summation: | Multiple signals integrated during a short period of time

Question 27

Spatial Signals

Answer 27

Type of Summation: | Additive effects based on the location of incoming signals

Question 28

Steps of an Action Potential

Answer 28

1. Voltage gated Na channels open and Na passes through into the cell making the membrane potential + and rapidly depolarizing 2. Voltage approaches + 35mV and Na channels become inactivated triggering the voltage gated K+ channels to open 3. Repolarization - K+ driven out of the cell and there is a restoration of the negative membrane potential 4. Hyperpolarization - K+ Efflux overshoots the resting potential and makes the neuron refractory to further action potentials 5. Na+ / K+ ATPase restores membrane potential and [ ] gradients

Question 29

Absolute Refractory Period

Answer 29

No amount of stimulation can cause an action potential

Question 30

Relative Refractory Period

Answer 30

Greater than normal stimulation can cause action potentials

Question 31

Impulse Propagation

Answer 31

Action potential much travel down the axon and initiate the neurotransmitter release ****info. can only flow in one direction

Question 32

Length of Axon

Answer 32

Longer the axon the higher the resistance and the slower the conduction of signals

Question 33

Cross Sectional Area of Axon

Answer 33

Greater cross sectional area allows faster propagation of signals due to decreased resistance

Question 34

Saltatory Conduction

Answer 34

Membrane is only permeable at the nodes of ranvier - Signal "hops" from node to node

Question 35

Neurotransmitters in Synaptic Cleft

Answer 35

Must be regulated / removed form synaptic cleft - Broken down by enzymatic reactions - Reuptake carriers bring them back to the presynaptic neuron - SImply diffuse out of the synaptic cleft

Question 36

Ca2+ Voltage Gated Channels

Answer 36

Ca2+ Channels open when an action potential reaches the nerve terminal causing exocytosis of the neurotransmitter - once released it diffuses across the cleft and binds to the receptors on the postsynaptic membrane allowing message to be passed from one neuron to the next

Question 37

Afferent Neurons

Answer 37

Afferent Signals Ascend: | Transmit sensory info from receptors to spinal cord / brain

Question 38

Efferent Neurons

Answer 38

Efferent Signals Exit: | Transmit motor info from brain / spinal cord to muscle / glands

Question 39

Interneurons

Answer 39

Found between other neurons and linked to reflexive behavior

Question 40

White Matter

Answer 40

- Deep within Brain | - Axons encased in myelin sheaths on outside of Spinal Cord

Question 41

Grey Matter

Answer 41

- Surface of Brain | - Unmyelinated cell bodies and dendrites deep within the Spinal Cord

Question 42

Central Nervous System

Answer 42

Consists of Brain and Spinal Cord

Question 43

Parts of Spinal Cord

Answer 43

1. Cervical 2. Thoracic 3. Lumbar 4. Sacral

Question 44

Peripheral Nervous System

Answer 44

Nerve tissues and fibers outside the brain that connects the Central Nervous System to the rest of the body

Question 45

Somatic System

Answer 45

Part of Peripheral Nervous System: | Sensory (afferent fibers) and motor (efferent fibers)

Question 46

Autonomic System

Answer 46

``` Part of Peripheral Nervous System: Involuntary muscles (automatic) and body temp ```

Question 47

Sympathetic Nervous System

Answer 47

"Fight or Flight" - Increase heart rate - Relax bronchi - Decrease digestion - Dilate eyes (max. light) - Epinephrine released into blood - [Glucose] in blood increased - Redistribute blood to muscles

Question 48

Parasympathetic Nervous System

Answer 48

"Rest and Digest" - Slow heart rate - Constrict bronchi - Stimulate digestion and bile release - Constrict pupils - Contracts bladder - Stimulates flow of saliva

Question 49

Reflex Arcs

Answer 49

Neural circuits control reflexive behavior. Interneurons in spinal cord can send signals to the muscles; info. is still sent to the brain but by the time it receives it the body has already responded

Question 50

Monosynaptic Reflex

Answer 50

Single synapse between sensory neuron that receives stimulation and motor neuron that respond Ex; Knee-Jerk Reflex

Question 51

Polysynaptic Reflex

Answer 51

At least one interneuron between the sensory and motor neuron ` Ex: Withdrawal Reflex