Chapter 11

Question 1

What is the function of microglia in the central nervous system?

Answer 1

Phagocytizing foreign substances in the CNS

Question 2

What happens to an axon after it has been cut?

Answer 2

The distal portion of the axon breaks into segments and dies

Question 3

How do graded potentials summate to reach threshold for action potentials?

Answer 3

Graded potentials combine at the tigger zone to reach a sufficient membrane voltage

Question 4

What is depolarization in the context of neuronal activity?

Answer 4

A decrease in the difference in electrical charge across the cell membrane

Question 5

What role do astrocytes play in the central nervous system?

Answer 5

To regulate extracellular fluid, support neurons, and modulate synaptic activity

Question 6

What role does reverberating circuit play in neural activity?

Answer 6

It allows prolonged stimulation of a pathway

Question 7

How do convergent pathways enhance sensory input processing?

Answer 7

By combining inputs from various sources into a single neuron

Question 8

How do neurotransmitters influence neuron communication?

Answer 8

By binding to receptors and initiating impulses

Question 9

Why is the neurotransmitter removal crucial after synaptic transmission?

Answer 9

To avoid prolonged activation of the postsynaptic neuron

Question 10

What mechanism allows for propagation of action potentials along the axon?

Answer 10

Sequential opening of voltage-gated ion channels

Question 11

How does a strong stimulus affect the neuron’s membrane potential?

Answer 11

It leads to depolarization and triggers an action potential

Question 12

Which type of nerve fibre is likely affected by mylenation issues?

Answer 12

Myelinated fibers

Question 13

How do glial cells contribute to nerve function?

Answer 13

They support and insulate neurons

Question 14

How do subthreshold, threshold, maximal, submaximal, and supramaimal stimuli differ?

Answer 14

They vary by effect on action potential frequency, with supramaximal stimuli not increasing the max

Question 15

What are the main components of a chemical synapse?

Answer 15

Presynaptic terminal, synaptic cleft, post synaptic membrane

Question 16

What is the function of oligodendrocytes in the CNS

Answer 16

To form insulating myelin sheaths and axons

Question 17

What is local and current and how does it contribute to action potential propagation?

Answer 17

A local current is the diffusion of ions that depolarizes the adjacent membrane, potentially triggering a new action potentials along

Question 18

What are the absolute and relative refractory periods in relation to action potentials?

Answer 18

Absolute: no action potential possible no matter the stimulus: relative potential if stimulus is stronger than threshold

Question 19

Which division of the nervous system is primarily responsible for voluntary movements

Answer 19

Somatic nervous system

Question 20

How does the nervous system facilitate communication within the body?

Answer 20

By transmitting electrical signals through neurons

Question 21

What are the two main cell types in nervous tissue ?

Answer 21

Neurons and glial cells

Question 22

What is the significance of myelin sheaths for axons?

Answer 22

To protect and insulate axons, speed transmission, and aid repair

Question 23

What is the resting membrane potentials, and what causes it?

Answer 23

The resting membrane potentials is around -70 to -90 my , caused by difference s in ion concentrations and membrane permeability

Question 24

What is hyper polarization and when does it occur?

Answer 24

When chloride ions enter the cell

Question 25

What is a nerve in the context of the nervous system?

Answer 25

A bundle of axons outside the Brian and spinal cord

Question 26

What are spatial temporal summation in the context of graded potentials?

Answer 26

Spatial summation involves graded potentials form different locations summing, while temporal summation involves graded potentials form the same locations summing summing

Question 27

What is a reverb acting circuit and what type of activities does it regulate?

Answer 27

A circuit that regulates rhythmic activities

Question 28

What role of the sodium- potassium pump in maintaining resting membrane potential?

Answer 28

It maintains the ion gradients and contributes to the resting membrane potential

Question 29

What is the function of convergent and divergent pathways in neural circuits?

Answer 29

Convergent pathways for data synthesis and divergent for widespread info

Question 30

How does the diameter of an axon influence the speed of action potential conduction?

Answer 30

A larger diameter increases the speed of action potential conduction

Question 31

What are the major divisions of the autonomic nervous system (ANS)?

Answer 31

Sympathetic, parasympathetic, and enteric

Question 32

How do neuronal pathways vary in complexity within the central nervous system

Answer 32

Neuronal pathways vary in complexity, with some pathways, lie convergent ones, connecting many inputs, and others like divergent ones, connecting a few inputs to many outputs

Question 33

What distinguishes type A nerve fibers from types B and C nerve fibers?

Answer 33

Larger diameter and heavy myelination

Question 34

What determines the maximum frequency of action potentials generated in a cell?

Answer 34

The absolute refractory period determines the maximum frequency

Question 35

What is the main function of neuromodulators in neural communication

Answer 35

To a dusty to the impact of neurotransmitters on postsynaptic cells

Question 36

How do neurotransmitters primarily affect postsynaptic cells?

Answer 36

By binding to specific receptors and altering ion flow

Question 37

How do graded potentials differ from action potentials?

Answer 37

Graded potentials diminish with distances while action potentials are self- propagating events

Question 38

What occurs during hyper polarization of a neuron?

Answer 38

The inside of the neuron becomes more negative

Question 39

What is the saltatory conduction and how does it affect action speed potential speed?

Answer 39

Jumping of action potentials from node to node, increasing speed

Question 40

What is the difference between excitatory inhibitory postsynaptic potentials?

Answer 40

EPSP’s cause depolarization, while IPSP’s cause hyperpolarization

Question 41

What is neuromodulation and how does it influence action potentials?

Answer 41

Influencing the likelihood of action potentials in postsynaptic cells

Question 42

What is the relationship between the number of dendrites and the structural classification of neurons

Answer 42

The number of dendrites is the basis for structural classification

Question 43

What distinguishes the somatic nervous system form the autonomic nervous system (ANS)?

Answer 43

The type of muscle gland they innervate and level of control

Question 44

What ions primarily influence the process of depolarization

Answer 44

Sodium and calcium ions

Question 45

How do neurotransmitters affect postsynaptic synaptic cells?

Answer 45

By binding to receptors and opening ion channels

Question 46

How does the structure of Schwann cells differ from that of oligodendrocytes?

Answer 46

Schwann cells wrap only one axon and possess a neurilemma, while oligodendrocytes myelinate several axons without neurilemma

Question 47

How do sensory receptors contribute to the peripheral nervous system ( PNS )

Answer 47

Sensory receptors transmit action potentials to the CNS

Question 48

What is the primary function of the central nervous system ( CNS)?

Answer 48

Integrating information

Question 49

What is the all-or-none principle regarding action potentials?

Answer 49

An action potential either occurs fully or does not occur at all if the threshold is reached

Question 50

What occurs at a synapse between presynaptic and post synaptic cells?

Answer 50

Neurotransmitters are released and bind to receptors

Question 51

What triggers the opening of voltage- gated ion channels during action potential?

Answer 51

Changes in the membranes voltage

Question 52

How does depolarization occur after an action potential?

Answer 52

Channels become inactivated and channels open allowing to move out of the cell

Question 53

What happens during depolarization of a neuron?

Answer 53

The cell interior shifts towards a more positive state