Chapter 2 Psych 002

Front 1

The human nervous system is compromised of?

Back 1

Neurons and Glia

Front 2

The human brain contains approx. ___ _______ individual neurons.

Back 2

100 Billion

Front 3

The cerebral cortex and associated area contains about _______ neurons.

Back 3

12 to 15 billion

Front 4

The cerebellum contains about _______ neurons.

Back 4

70 billion

Front 5

The spinal cord contains about ______ neurons.

Back 5

1 billion

Front 6

- In the late 1800's, what did Spaniard Santiago Ramon y Cajal demonstrate?

- What did he show?

Back 6

- First to demonstrate that the individual cells compromising the nervous system remained separate.

- Showed that they did not grow into each-other as previously believed.

Front 7

What do neurons contain?

Back 7

Membrane, Nucleus, Mitochondria, Ribosomes, Endoplasmic reticulum

Front 8

What are the parts of a cell?

Back 8

Cell membrane, Nucleus, Mitochondria, Ribosomes, Endoplasmic reticulum.

Front 9

What does the cell membrane do?

Back 9

separates the inside of the cell from the outside environment.

Front 10

What does the nucleus do?

Back 10

contains the chromosomes

Front 11

What does the mitochondria do?

Back 11

structure that performs metabolic activities and provides energy for the cells.

Front 12

Define ribosomes

Back 12

sites at which the cell synthesizes new protein molecules.

Front 13

Define Endoplasmic reticulum

Back 13

network of thin tubes that transport newly synthesized proteins to their location

Front 14

What are the three types of Neurons that we will discuss?

Back 14

Motor Neurons, Sensory Neurons, and Intrinsic Neurons

Front 15

Define Motor Neurons

Back 15

- Take information from the brain and send it to the muscles.

- Receive information from the brain, run through the spinal cord, and have a long axons that extend to, and synapse with, a muscle.

Front 16

Define Sensory Neurons

Back 16

- Take information from our senses and send it to the brain.

- Are connected to our sense organs and extend to our spinal cord, and then to the brain.

Front 17

Which parts of the sensory neurons don't go through the spinal cord?

Back 17

our ears and eyes, because they are so close to our brain.

Front 18

Define Intrinsic Neurons

Back 18

- Neurons that are entirely in the spinal cord or brain.

- Often, once a sensory or motor neuron reaches the spinal cord, it synapses with an intrinsic Neuron which passes the information along by synapsing with other motor or sensory neurons.

Front 19

What are all of the major components of neurons?

Back 19

Dendrites, Soma/Cell Body, Axon, Presynaptic terminals (axon terminals)

Front 20

Define Dendrites

Back 20

Are branching fibers with a surface lined with synaptic receptors responsible for bringing information into the neuron.

Front 21

What do some dendrites also contain?

Back 21

Also contain dendrite spines.

Front 22

What do Dendrite spines do?

Back 22

They further branch out and increase the surface area of the dendrite.

Front 23

The greater the surface area of the dendrite, the more __________ __ ____ ________.

Back 23

information it can receive.

Front 24

What does the cell body/soma contain?

Back 24

contains the nucleus, mitochondria, ribosomes, and other cell structures.

Front 25

Define Axon

Back 25

Thin fiber of a neuron responsible for transmitting nerve impulses toward other neurons, organs or muscles.

Front 26

Define myelin

Back 26

Insulating materials that cover some neurons

Front 27

Define Presynaptic terminals

Back 27

the end points of an axon where chemicals are released to communicate with other neurons

Front 28

What are the two terms that describe the neuron.

Back 28

Afferent axon and efferent axon

Front 29

Define Afferent Axon

Back 29

Bringing information into a structure

Front 30

Define Efferent Axon

Back 30

Carrying information away from a structure

Front 31

What does the shape of a neuron determine?

Back 31

It's connection with other neurons and contribution to the nervous system.

Front 32

What is the Glia?

Back 32

The other major components of the nervous system

Front 33

What are some of the functions of Glia?

Back 33

- Help synchronize the activity of the axon by wrapping around the presynaptic terminal and taking up chemicals released by the axon.

- Remove waste material and other microorganisms that could prove harmful to the neuron.

- Build the myelin sheath that surrounds and insulates certain vertebrate axons.

- Guide the migration of neurons and the growth of their axons and dendrites during embryonic development.

Front 34

Define the Blood-Brain Barrier

Back 34

- Is a mechanism that surrounds the brain and blocks most chemicals from entering it

- Made of cells that are very tightly packed together

Front 35

What does the blood brain barrier block?

Back 35

Incoming viruses, bacteria, or other harmful material from getting into the brain.

Front 36

What molecules pass freely through the Barrier?

Back 36

Oxygen and carbon Dioxide

Front 37

What particles need help to pass through the barrier?

Back 37

Glucose and amino acids

Front 38

Define Active Transport

Back 38

is the protein-mediated process that expends energy to pump certain chemicals from the bloodstream into the brain.

Front 39

What uses active transport to get to the brain?

Back 39

Glucose, certain hormones, amino acids, and a few vitamins.

Front 40

What are all results from BBB Breakdown?

Back 40

Meningitis, Multiple Sclerosis, and perhaps Alzheimer's Disease

Front 41

What do neurons rely on for energy?

Back 41

Glucose

Front 42

What do neurons also need a steady supply of?

Back 42

Oxygen, 20% of all oxygen consumed by the body is used by the brain

Front 43

What does the body need to use glucose?

Back 43

Thiamine (Vitamin A)

Front 44

At rest, what does a neuron maintain?

Back 44

It maintains an electrical polarization or a difference in the electrical charge of the two locations

Front 45

Define resting potential

Back 45

the state of the neuron prior to the sending of a nerve impulse

Front 46

Define selectively permeable

Back 46

Allowing some chemicals to pass more freely than others

Front 47

What passes through channels in the membrane?

Back 47

Sodium, Potassium, Calcium, and chloride

Front 48

Define the sodium-potassium pump

Back 48

Is a protein complex that continually pumps 3 sodium ions out of the cells while drawing 2 potassium ions into the cell which maintains the negative charge

Front 49

Define the electrical gradient

Back 49

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

Front 50

Define the concentration gradient

Back 50

Means the cell tries to maintain a balance of potassium and sodium inside and outside the cell

Front 51

What pulls potassium ions into the cell?

Back 51

Electrical gradient

Front 52

Define action potential

Back 52

is a rapid depolarization of the neuron

Front 53

define threshold of excitation

Back 53

A level above which any stimulation produces an action potential

Front 54

The resting potential remains stable until the neuron is _________.

Back 54

stimulated

Front 55

Define Hyperpolarization

Back 55

Increasing the polarization or the difference between the electrical charge of two places

Front 56

Define Depolarization

Back 56

Decreasing the polarization towards zero

Front 57

In an action potential what happens to Sodium ions and its channels?

Back 57

Sodium channels are opened, positively charged sodium ions rush in and a subsequent nerve impulse occurs.

Front 58

After an action potential occurs, what happens to the sodium channels?

Back 58

Quickly close

Front 59

Why do potassium ions flow out?

Back 59

Due to the concentration gradient

Front 60

What do local anesthetic drugs do?

Back 60

They block sodium channels and therefore prevent action potentials rom occuring

Front 61

Define the all-or-none law

Back 61

States that the amplitude and velocity of an action potential are independent of the intensity of the stimulus that initiated it.

Front 62

After an action potential what period does a neuron enter?

Back 62

Refractory Period

Front 63

Define the refractory period

Back 63

The neuron resists the production of another action potential

Front 64

Define the absolute refractory period

Back 64

is the first part of the period in which the membrane cannot produce an action potential

Front 65

Define the relative refractory period

Back 65

is the second part of the period which it takes a stronger than usual stimulus to trigger an action potential

Front 66

What are the myelin sheath of axons interrupted by?

Back 66

Nodes of Ranvier

Front 67

What happens at each node of Ranvier?

Back 67

the action potential is regenerated by a chain of positively charged ion pushed along by the pervious segment.