nervous system

Question 1

Sensory system is afferent or efferent?

Answer 1

Afferent

Question 2

What are the two types of neurotransmitters?

Answer 2

Ionotropics (that gate ions (Ca, K, or Cl)) and metabotropics (that act on second messengers)

Question 3

How many nerve pairs are in each section of the spinal cord?

Answer 3

Cervical 8, thoracic 12, lumbar 5 and sacral 5

Question 4

What are the differences between receptor potential and action potential?

Answer 4

Receptor potential can be summated, does not obey all or none rule, is in the receptor, graded and is unpropagated. Action potential is in the sensory nerve fiber, not graded, obeys all or none rule, not summated and is propagated

Question 5

What type of glial cells is in the CNS and PNS?

Answer 5

Schwann cells in PNS and oligodendrocytes in CNS

Question 6

What is the main difference between axon and dendrites?

Answer 6

Dendrites cannot generate action potential as they dont have Na channels

Question 7

What ion is more concentrated intracelullarly than extra?

Answer 7

K

Question 8

If positive charge is introduced in the membrane, that membrane is

Answer 8

Depolarized

Question 9

What are the types of sensory receptors?

Answer 9

Mechano, thermal, chemical, electromagnetic and nociceptors

Question 10

Looking from the side, What part of the brain is located in front of the central sulcus? and behind?

Answer 10

frontal lobe and parietal lobe

Question 11

What parts of the brain are located in front and behind the central sulcus looking from above?

Answer 11

Pre central gyrus and post central gyrus

Question 12

Low K concentration extracelularly causes:

Answer 12

Hypokalemia, membrane is hyperpolarized

Question 13

In Hypokalemia the potential is:

Answer 13

Lower than the resting potential, Hyperpolarized

Question 14

Hyperkalemia is when:

Answer 14

The K concentration extracelularly is higher than normal and so the membrane potential will be depolarized

Question 15

Gray matter contains _______ and white matter contains _____

Answer 15

neurons and axons

Question 16

An anion is an ion with a _______ charge

Answer 16

negative

Question 17

Motor neurons leave spinal cord from _____ side

Answer 17

ventral

Question 18

Thousands of axons form a ____in PNS and is called _____in CNS

Answer 18

nerve and tracts

Question 19

Nernst equation is:

Answer 19

(EMF) = ± 61/z×log ([]inside)/([]outside)

Question 20

Na has ____ channels and Ca has _____ channels

Answer 20

Fast and slow

Question 21

What is saltatory conduction?

Answer 21

It’s the conduction of action potential between nodes of ranvier, where the potential is recharged at each node, since that is where the Na channels have access to the axon as these sections are not myelinated

Question 22

What is absolute refractory period?

Answer 22

It’s the period after an action potential when another action potential cannot be created no matter the stimulus, this happens because during this period the inactivation gates of the Na channels are closed, and they can only open again when the membrane resting potential is restored.

Question 23

What is relative refractory period?

Answer 23

It’s the period after an action potential when another potential can be created but it requires stronger stimulus, because the membrane potential is hyperpolarized thus to create a new action potential the new stimulus must overcome the hyperpolarization to reach the threshold.

Question 24

Why does the action potential does not move backwards?

Answer 24

Because of the absolute refractory period the Na channels inactivation gates are closed and cannot be open until resting potential is returned, thus no action potential can be created in this backward direction

Question 25

Explain chemical synapse:

Answer 25

The presynaptic terminal is close to the postsynaptic terminal and between them there is a synaptic cleft. In the presynaptic terminal there are vesicles that hold neurotransmitters and when a action potential is received the Ca channels open and these vesicles move toward the cleft and release the neurotransmitters that will be received in the postsynaptic terminal by receptor proteins, depending on the neurotransmitter this can excite or inhibit the neuron.
Also the presynaptic cleft has mitochondria that provide energy to synthesize neurotransmitters

Question 26

Neurotransmitter that open cation channels are called ________ transmitters and those that open anion channels are ______ transmitters.

Answer 26

Excitatory and inhibitory

Question 27

Electrical synapse is more common in:

Answer 27

Visceral, smooth and cardiac muscles

Question 28

Chemical synapse move _______ and electrical synapse moves ________

Answer 28

in only one way, in both ways

Question 29

Examples of small and fast acting Synaptic transmitters

Answer 29

Acetylcholine, epinephrine, dopamine, serotonin

Question 30

Acetylcholine is mostly excitatory but can be inhibitory in the

Answer 30

peripheral parasympathetic nerve endings

Question 31

Inhibitory signals open ___ channels allowing its influx and open __ channels allowing its outflux, making the membrane potential more negative

Answer 31

Cl, K

Question 32

Presynaptic inhibition is the release of inhibitory substances _____ on the outside of presynaptic nerve, allowing Cl to enter, which will cancel some of the Na that enter when a action potential is produced

Answer 32

GABA

Question 33

What are the main differences between spatial and temporal summation?

Answer 33

Spatial is the summation of stimuli from more than one terminal while temporal is the summation of stimuli of one terminal that happen multiple consecutive times rapidly

Question 34

What is decremental conduction?

Answer 34

Is the decay of conduction of a stimuli in the dendrites, as they are not insulated and are permeable to Cl and K ions, thus signals that are farther away from the soma loose more strength and must be of greater intensity to cause a action potential or inhibition than signals close to the axon hillock

Question 35

What is fatigue of a neuron?

Answer 35

If a stimuli is continuous the firing rate decreases with more time of excitation of a neuron because of exhaustion of the reserves of neurotransmitters in the vesicles in presynaptic terminals.

Question 36

_______ increases neuronal excitability causing seizures, while _______ depresses neuronal activity and cause coma.

Answer 36

Alkalosis, acidosis

Question 37

Caffeine is a excitatory drug that ______ the threshold for excitation of neurons

Answer 37

Lowers

Question 38

What is the labeled line principle?

Answer 38

It’s how the brain interprets signals from the sensory nerves, each nerve tract terminates at a specific point in the CNS, the type of sensation felt is determined by the point in the nervous system to which the fiber leads.

Question 39

What are the fastest adapting nerve endings?

Answer 39

Pacinian receptor, followed by hair receptors. Joint capsule and muscle spindle are slow to adapt, aka tonic

Question 40

sensory info from somatic system enters the spinal cord through:

Answer 40

dorsal roots of the spinal nerves.

Question 41

The Dorsal (or posterior) column-medial lemniscus transmits:

Answer 41

Faster signals, conveys light touch, proprioception and vibrations, has high fidelity of temporal and space. Has distinct orientation of nerve fibers from individual parts of the body.

Question 42

The Anterolateral (or spinothalamic) system transmits:

Answer 42

Slower, transmits pain, thermal sensations, crude touch, tickle and itch

Question 43

Cell bodies of sensory neuron is located in

Answer 43

dorsal root ganglia, that is outside spinal cord

Question 44

Pain is transmitted through:

Answer 44

anterolateral system