Brain Organization and Neural Functioning

Question 1

Golgi vs. Rámon y Cajal

Answer 1

Golgi: Neurons are continuous

Rámon y Cajal: Neurons come close to one another but are not connected

Question 2

Neuron Doctrine

Answer 2

The brain is composed of separate cells that are distinct structurally, metabolically and functionally

Question 3

Sir Charles Sherrington

Answer 3

Termed the synpase

Question 4

Multipolar Neuron

Answer 4

A nerve cell that has many dendrites and a single axon

Question 5

Bipolar Neuron

Answer 5

A nerve cell that has a single dendrite at one end and a single axon on the other end

Question 6

Neural Plasticity

Answer 6

The ability of the nervous system to change in response to experience or the environment

Question 7

Glial Cells

Answer 7

Glial cells support and enhance neural activity: they communicate with each other and with neurons, and they directly affect neuronal functioning by providing neurons with raw materials and chemical signals that alter neuronal structure and excitability.

Make up myelin

Question 8

Myelin/Myelination

Answer 8

The fatty insulation around an axon formed by glial cells, that improves the speed of conduction of nerve impulses.

Less myelin = action potential

Question 9

Peripheral Nervous System

Answer 9

All nervous system parts that are outside the bony skull and spinal column

Question 10

Central Nervous System

Answer 10

Consists of the brain and spinal cord

Question 11

Dorsal

Answer 11

Towards the back

Question 12

Ventral

Answer 12

Toward the belly, front

Question 13

Anterior

Answer 13

Head

Question 14

Posterior/Caudal

Answer 14

Back

Question 15

Parasympathetic Nervous System

Answer 15

Helps the body relax, recuperate, and prepare for future action (Uses Acetylcholine)

Question 16

Sympathetic Nervous System

Answer 16

Prepares the body for action (Uses Norepinephrine)

Question 17

Corpus Callosum

Answer 17

The main band of axons that connects the two cerebral hemispheres

Question 18

White Matter

Answer 18

A shiny layer underneath the cortex that consists largely of axons with white myelin sheaths

Question 19

The Limbic System

Answer 19

Critical for emotion and learning
Includes:
Amygdala
Hippocampus
Fornix

Question 20

Hippocampus

Answer 20

A medial temporal lobe structure that is important for learning and memory

Question 21

Thalamus

Answer 21

A complex cluster of nuclei that acts as a switch box, directing almost all incoming sensory information to the appropriate regions of the cortex for further processing.

Question 22

Hypothalamus

Answer 22

Packed with discrete nuclei, it is involved in many functions such as hunger, thirst, temperature regulation. It also controls the pituitary gland serving as the brains main interface with the hormonal system.

Question 23

The Ventricular System

Answer 23

A system of fluid-filled chambers inside the brain
Includes:
Lateral Ventricle- The lateral portion of the VS system within each hemisphere of the brain
Third Ventricle- The midline ventricle that conducts cerebrospinal fluid from the lateral ventricle to the fourth ventricle
Fourth Ventricle- The passageway within the pons that receives cerebrospinal fluid from the third ventricle and releases it to surround the brain and spinal cord.

Question 24

All living cells are more (positive/negative) on the inside…

Answer 24

Negative

Question 25

Ion

Answer 25

An electrically charged molecule

Question 26

Resting Membrane Potential

Answer 26

An electrical-potential difference across the membrane. Usually of about -50 to -80 mV

Question 27

Potassium Ion (K+)

Answer 27

Carries a positive charge

Question 28

Concentration Gradient

Answer 28

Variation of the concentration of a substance within a region

Question 29

Sodium Ion (Na+)

Answer 29

Carries a positive charge

Question 30

Sodium Ion Pump

Answer 30

Pumps three Na+ out for every two K+ in

Question 31

The Nernst Equation

Answer 31

Predicts the voltage needed to counterbalance the diffusion force pushing an ion across a semipermeable membrane from the side with a high concentration to the side with a low concentration

Question 32

Hyperpolarization

Answer 32

An increase in membrane potential (i.e the neuron becomes more negative on the inside, relative to the outside) (INHIBITORY)

Question 33

Depolarization

Answer 33

A reduction in membrane potential (i.e the interior of the neuron becomes less negative by letting in Na+) (EXCITATORY)

Question 34

Local Potentials

Answer 34

An electrical potential that is initiated by simulation at a specific site, which is a graded response that spreads passively across the cell membrane, decreasing in strength with time and distance.

Question 35

Threshold

Answer 35

The stimulus intensity that is just adequate to trigger an action potential (about -40 mV)

Question 36

Action Potential

Answer 36

A rapid reversal of the membrane potential that momentarily makes the inside of the membrane positive with respect to the outside.

Question 37

Applying strong stimuli to action potentials

Answer 37

Larger depolarizations produce more action potentials, not larger action potentials The size (or amplitude) of the action potential is independent of stimulus magnitude.

Question 38

All-or-None Property

Answer 38

Either it fires at its full potential or it does not fire at all

Question 39

Hodgkin and Huxley

Answer 39

Established that the action potential is created by the movement of sodium ions (Na+) into the cell, through channels in the membrane.

Question 40

Action Potential

Answer 40

At its peak, the AP approaches equilibrium potential for Na+ as predicted by the Nernst Equation (about +40mV) The concentration gradient is balanced between negative and positive ions The membrane shifts properties, now depending on sodium, then returning to the resting state

Question 41

Voltage-Gated Na+ Channels

Answer 41

A Na+ selective channel that opens or closes in response to changes in the voltage of the local membrane potential; it mediates the action potential

Question 42

Axon Hillock

Answer 42

A cone-shaped area from which the axon originates out of the cell body. Functionally, the integration zone of the neuron

Question 43

Nodes of Ranvier

Answer 43

A gap between successive segments of the myelin sheath where the axon membrane is exposed.

Question 44

Neurotransmitter

Answer 44

A converted electrical signal, released from the presynaptic axon terminal that serves as the basis of communication between neurons

Question 45

EPSP

Answer 45

A depolarizing potential in the postsynaptic neuron that is caused by excitatory connections. EPSPs increase the probability that the post synaptic neuron will fire an action potential

Question 46

IPSP

Answer 46

A hyper polarizing potential in the post synaptic neuron that is caused by inhibitory connections. IPSPs decrease the probability that the postsynaptic neuron will fire an action potential

Question 47

Synaptic Transmission

Answer 47

1. Action potential arrives at the axon terminal 2. This depolarization opens voltage-gated calcium channels in the membrane, allowing calcium (Ca2+) to enter 3. Ca2+ causes synaptic vesicles filled with neurotransmitters to fuse with the presynaptic cell 4. The NTs are released into the synaptic cleft 5. Transmitter molecules cross the cleft to bind with special receptors, leading to the opening of ion channels in the postsynaptic membrane. 6. This creates an EPSP or an IPSP 7. EPSP and IPSPs spread and determine if there will be another action potential

Question 48

Calcium Ions (Ca2+)

Answer 48

Activate enzymes that cause vesicles near the presynaptic membrane to fuse with the membrane and discharge their contents into the synaptic cleft.

Question 49

Ligand

Answer 49

A substance that binds the receptor molecules, such as those at the surface of the cell.

Question 50

Agonist vs Antagonist

Answer 50

Agonist: A molecule, usually a drug, that binds a receptor molecule and initiates a response like that of another molecule, usually a NT Antagonist: A molecule that interferes with or prevents the action of a transmitter

Question 51

Loewi

Answer 51

Discovered the nervous system, long known to use electrical signals, uses chemical signals as well Discovered ACh

Question 52

Ionotropic Receptor

Answer 52

A receptor protein that includes an ion channel that is opened when the receptor is bound by an agonist

Question 53

Ligand-Gated Ion Channel

Answer 53

Also known as chemically gated ion channel | An ion channel that opens or closes in response to the presence of a particular chemical

Question 54

Metabotropic Channel

Answer 54

A receptor protein that does not contain an ion channel but may, when activated, use a G protein system to alter functioning of the postsynaptic cell

Question 55

Degradation

Answer 55

When a transmitter is broken down and thus inactivated

Question 56

Reuptake

Answer 56

The process by which released synaptic transmitter molecules are taken up and reused by the presynaptic neuron, thus stopping synaptic activity.