Neurons & Synapses

Question 1

What are the main components of a neuron?

Answer 1

Soma (cell body), Dendrites, Axon, myelin sheath, nodes of ranvier, presynaptic terminals, axon hillock

Question 2

What are the different types of neurons?

Answer 2

Multipolar (more than 2 neurites) , Bipolar (2 neurties), Pseudounipolar neuron (one neurite extending from cell body)

Question 3

What are the types of synapses?

Answer 3

Electrical Synapse & Chemical synapse

Question 4

What is an electrical synapse? What does it need?

Answer 4

Relatively simple structure allowing the direct transfer of ionic current from one cell to another; Gap junction, connexins, and connexons

Question 5

What is a chemical synapse? What does it need?

Answer 5

Specialized pre- and post- synaptic structures employing chemicals to transfer information between a neuron and another neuron or cell type

Question 6

What are the types of Chemical synapses based on location?

Answer 6

Axo-dendritic, Axo-somatic, Axo-axonic

Question 7

What are examples of chemical excitatory synapses? Inhibitory?

Answer 7

Excitatory: Glutamate & Aspartate
Inhibitory: GABA & Glycine

Question 8

What are the structures involved in a chemical synapse?

Answer 8

Axon, mitochondrion, Synaptic vesicles, pre-synaptic membrane, synaptic cleft, post-synaptic membrane, post-synaptic receptors

Question 9

What are the glial cells? What do they do?

Answer 9

Oligodendrocytes: form the myelin sheath in the CNS
Schwann cells: cells that form the myelin sheath in the PNS
Astrocytes: Provide structural and functional support, and nutrients
Microglia: Acts as phagocytes
Ependymal cells: epithelial cells lining the ventricles

Question 10

What are the properties of the phospholipid membrane?

Answer 10

Bilayer with polar (hydrophylic) heads on the outside and non-polar (hydrophobic) tails on the inside

Question 11

What are the levels of protein structure?

Answer 11

Primary, Secondary, Tertiary, Quaternary

Question 12

What is diffusion? How does it work?

Answer 12

Dissolved ions distribute evenly because ions flow down concentration gradient when the channels are permeable to specific ions

Question 13

What is the Equilibrium Potential (Eion)?

Answer 13

No net movement of ions when separated by a phospholipid membrane. Point at which voltage difference exactly balances ionic concentration gradient

Question 14

What is the Nernst Equation used for? What does it take into consideration?

Answer 14

Used to calculate the exact value of the equilibrium potential for each ion. Takes into consideration: charge of the ion, temperature, ratio of the external and internal ion concentrations

Question 15

What is the Resting Membrane Potential of K+?

Answer 15

-80mV; concentrated more on inside than out

Question 16

What is the Resting Membrane Potential of Na+?

Answer 16

62 mV; more concentrated on outside than inside

Question 17

What is the Resting Membrane Potential of Ca2+?

Answer 17

123mV; more on outside than inside

Question 18

What is the Resting Membrane Potential of Cl-?

Answer 18

-65mV; more on outside than inside

Question 19

What is the resting membrane potential?(#)

Answer 19

-65mV

Question 20

What does the Goldman Equation take into consideration?

Answer 20

Permeability of membrane to different ions

Question 21

What are the forces that maintain the resting membrane potential?

Answer 21

Passive forces - use no energy (Diffusion and Electrical forces)
Active forces - uses energy ATP (Na+/K+ pump)

Question 22

What is hyperpolarization?

Answer 22

Increases polarization of nerve cells: inside more negative; concept of IPSP

Question 23

What is depolarization?

Answer 23

Decreases polarization of nerve cells: inside less negative; concept of EPSP

Question 24

How are synaptic potentials produced?

Answer 24

Neurotransmitters bind to NT recepotr on post-synaptic membrane. Binding opens ion channels in the post-synaptic membrane and produces IPSP and EPSP

Question 25

What is the concept of spatial summation?

Answer 25

• 2 simultaneous EPSP or IPSP on different neurons sum to produce a greater potential
• a simultaneous EPSP and IPSP lesson each other

Question 26

What is the concept of temporal summation?

Answer 26

-2 EPSP or 2 IPSP elicited in rapid succession sum to produce a larger potential

Question 27

Where are excitatory synapses found? Inhibitory synapse?

Answer 27

Excitatory synapse located at distal dendrite. Inhibitory synapse located more proximally at cell bodies