Nervous system

Question 1

What is the function of the nervous system?

Answer 1

It controls and coordinates body activities using electrical impulses.

Question 2

What are the two main divisions of the nervous system?

Answer 2

Central Nervous System (CNS): brain and spinal cord

Peripheral Nervous System (PNS): all other nerves

Question 3

What does the hypothalamus do?

Answer 3

Regulates body temperature, hunger, thirst, circadian rhythms, and links the nervous and endocrine systems.

Question 4

Why is the pituitary gland called the “master gland”?

Answer 4

It releases hormones that control growth, metabolism, and reproduction.

Question 5

What is the function of the brainstem?

Answer 5

Controls vital autonomic functions like breathing and blood pressure.

Question 6

What is the cerebrum responsible for?

Answer 6

Conscious thought, memory, language, and voluntary movement.

Question 7

What is the cerebral cortex?

Answer 7

The folded outer layer of the brain responsible for higher thinking; divided into lobes.

Question 8

What is the role of the spinal cord?

Answer 8

Sends signals between the brain and body and controls reflexes.

Question 9

What are the two divisions of the autonomic nervous system?

Answer 9

Sympathetic: fight or flight

Parasympathetic: rest and digest

Question 10

What is a neuron?

Answer 10

A specialized cell that transmits electrical and chemical signals in the body.

Question 11

Where are neurons most concentrated?

Answer 11

The cerebellum.

Question 12

What is the function of the cerebellum?

Answer 12

Coordinates voluntary movement, balance, posture, and motor learning.

Question 13

What are sensory neurons?

Answer 13

Neurons that carry information from receptors to the CNS.

Question 14

What are motor neurons?

Answer 14

Neurons that send signals from the CNS to muscles or glands.

Question 15

What are relay (interneurons) neurons?

Answer 15

Neurons that connect sensory and motor neurons.

Question 16

What is the function of dendrites?

Answer 16

They receive incoming signals.

Question 17

What does the axon do?

Answer 17

Carries electrical signals away from the cell body.

Question 18

What is myelin and why is it important?

Answer 18

A fatty insulating layer that speeds up nerve impulses

Question 19

What are glial cells?

Answer 19

Support cells that nourish and protect neurons but do not conduct impulses.

Question 20

What is an action potential?

Answer 20

A rapid, temporary change in a neuron’s electrical charge that allows signal transmission.

Question 21

What is the resting membrane potential?

Answer 21

About −70 mV when the neuron is not firing.

Question 22

What ions are more concentrated outside the neuron at rest?

Answer 22

Sodium (Na⁺).

Question 23

What ions are more concentrated inside the neuron at rest?

Answer 23

Potassium (K⁺)

Question 24

What does the sodium-potassium pump do?

Answer 24

Pumps 3 Na⁺ out and 2 K⁺ in using ATP to maintain resting potential.

Question 25

What is the threshold potential?

Answer 25

Around −55 mV; the minimum charge needed to trigger an action potential.

Question 26

What happens during depolarization?

Answer 26

Sodium channels open and Na⁺ rushes in, making the inside positive.

Question 27

What happens during repolarization?

Answer 27

Sodium channels close, potassium channels open, and K⁺ leaves the cell.

Question 28

What is hyperpolarization?

Answer 28

When the membrane potential drops below resting level (around −80 mV).

Question 29

What is the refractory period?

Answer 29

The time after an action potential when the neuron cannot fire again.

Question 30

What is saltatory conduction?

Answer 30

When impulses jump between nodes of Ranvier in myelinated neurons, making signals faster and more efficient

Question 31

What is a synapse?

Answer 31

The tiny gap between the axon terminal of one neuron and the dendrite of another where communication occurs.

Question 32

Is a synapse a physical connection?

Answer 32

No. It is a chemical bridge, not a physical connection.

Question 33

What are the three main parts of a synapse?

Answer 33

Presynaptic neuron, synaptic cleft, postsynaptic neuron.

Question 34

What does the presynaptic neuron do?

Answer 34

Sends the signal.

Question 35

What is the synaptic cleft?

Answer 35

The 20–40 nm gap between neurons where neurotransmitters travel.

Question 36

What does the postsynaptic neuron do?

Answer 36

Receives the signal.

Question 37

What travels inside a neuron?

Answer 37

An electrical signal called an action potential.

Question 38

What triggers neurotransmitter release?

Answer 38

An action potential reaching the axon terminal and opening voltage-gated calcium channels.

Question 39

What role does calcium play at the synapse?

Answer 39

Calcium influx causes synaptic vesicles to release neurotransmitters.

Question 40

Where are neurotransmitters stored?

Answer 40

In synaptic vesicles.

Question 41

How do neurotransmitters affect the next neuron?

Answer 41

They bind to receptors and open ion channels.

Question 42

What happens if the signal is strong enough?

Answer 42

A new action potential is triggered in the postsynaptic neuron.

Question 43

Why is the lock-and-key model used?

Answer 43

Only the correct neurotransmitter can bind to a specific receptor.

Question 44

What happens when neurotransmitters bind to receptors?

Answer 44

Ion channels open, changing the membrane potential.

Question 45

What is an excitatory synapse?

Answer 45

A synapse that increases the likelihood the next neuron will fire.

Question 46

Example of an excitatory neurotransmitter?

Answer 46

Glutamate.

Question 47

What ion channels open in excitatory synapses?

Answer 47

Sodium (Na⁺) channels.

Question 48

What is an inhibitory synapse?

Answer 48

A synapse that decreases the likelihood the next neuron will fire

Question 49

Example of an inhibitory neurotransmitter?

Answer 49

GABA.

Question 50

What ions are involved in inhibitory synapses?

Answer 50

Chloride (Cl⁻) or potassium (K⁺).

Question 51

What is hyperpolarization?

Answer 51

When the neuron becomes more negative and less likely to fire

Question 52

Why must neurotransmitters be removed?

Answer 52

To prevent continuous firing of the neuron.

Question 53

What is reuptake?

Answer 53

The presynaptic neuron reabsorbs the neurotransmitter.

Question 54

What is enzymatic breakdown?

Answer 54

Enzymes destroy the neurotransmitter (e.g., acetylcholinesterase).

Question 55

What is diffusion?

Answer 55

Neurotransmitters drift away from the synapse.

Question 56

Why is acetylcholine important?

Answer 56

It was the first neurotransmitter discovered and helped scientists understand synapses.

Question 57

What functions use acetylcholine (voluntary)?

Answer 57

Muscle contraction, memory, learning, attention, arousal.

Question 58

What functions use acetylcholine (involuntary)?

Answer 58

Heart rate, blood pressure, digestion.

Question 59

Where is acetylcholine used?

Answer 59

Both the CNS and PNS.

Question 60

What enzyme breaks down acetylcholine?

Answer 60

Acetylcholinesterase.

Question 61

What is an electrical synapse?

Answer 61

A direct physical connection between neurons.

Question 62

What structure connects neurons in electrical synapses?

Answer 62

Gap junctions.

Question 63

How do signals travel in electrical synapses?

Answer 63

Ions flow directly from one neuron to another.

Question 64

How are electrical synapses different from chemical synapses?

Answer 64

They are faster but less common.

Question 65

Why are electrical synapses useful?

Answer 65

They allow rapid, synchronized communication in the brain