Week 5 Readings Flashcards
1
Q
What are the 5 different sensory systems that neurons receive information from?
A
Vision, audition, olfaction, gustation and somatosensation
2
Q
Who is considered the father of modern neuroscience for concluding that neurons are the structural and functional units of the nervous system?
A
Santiago Ramón y Cajal (1911).
3
Q
What staining technique did Santiago Ramón y Cajal use to observe individual neurons?
A
The Golgi stain.
4
Q
What is unique about the Golgi stain in terms of neuron visualization?
A
The Golgi stain fills the entire cell body and its processes but only stains about 1-2% of neurons.
This low percentage is actually a big advantage because if all the neurons were stained, they would overlap, making it hard to distinguish one neuron from another. By only staining a few neurons, the Golgi stain allows scientists to see the detailed structure of individual neurons clearly, without interference from surrounding cells.
5
Q
What does a Nissl stain label?
A
Only the main part of the cell (i.e, the cell body)
6
Q
What was Camillo Golgi’s stance on the structure of the nervous system, and how did it differ from Cajal’s view?
A
Golgi supported the theory that the nervous system was a continuous network (theory by Joseph von Gerlach), while Cajal argued that neurons were individual, distinguishable processing units.
7
Q
How did Cajal’s use of the Golgi stain revolutionize our understanding of the nervous system?
A
It allowed him to observe the full anatomical structure of individual neurons for the first time, challenging the idea of a continuous nerve network.
8
Q
What are the three main components of a neuron?
A
Dendrites, soma (cell body), and axon.
9
Q
What is the primary function of dendrites in a neuron?
A
Dendrites receive information from thousands of other neurons and serve as the main source of input for the neuron.
10
Q
What part of the neuron contains the nucleus and directs protein synthesis?
A
The soma (cell body).
11
Q
What is the role of the nucleus in a neuron?
A
The nucleus contains genetic information, directs protein synthesis, and provides the neuron with energy and resources to function.
12
Q
What is the function of the axon in a neuron?
A
The axon carries an important signal, called an action potential, from the neuron’s soma to another neuron. It acts as the main source of output for the neuron.
13
Q
Where does communication between two neurons typically occur?
A
At the synapse, the point where the axon of one neuron comes into close contact with the dendrite of another neuron.
14
Q
What is the function of the myelin sheath, and where is it found?
A
The myelin sheath is an insulating layer that covers the axon, allowing electrical signals to travel rapidly between neurons.
15
Q
What signal does the axon carry to other neurons?
A
An action potential.
16
Q
What happens to the axon as it approaches other neurons?
A
The axon splits many times to communicate or synapse with several other neurons.
17
Q
What is located at the end of the axon, and what is its role?
A
The terminal button, which forms synapses with spines on the dendrites of other neurons.
18
Q
What are the two components involved in a synapse?
A
The presynaptic terminal button (the neuron sending the signal) and the postsynaptic membrane (the neuron receiving the signal).
19
Q
Besides dendritic spines, what other structures can form synapses with the terminal button of an axon?
A
Synapses can also form with the soma (cell body) or the axon of another neuron.
20
Q
What are dendritic spines?
A
Protrusions on dendrites where synapses are formed with the terminal button of an axon.
21
Q
What is the significance of the terminal button in neural communication?
A
The terminal button is where neurotransmitters are released to transmit signals to other neurons at the synapse.
22
Q
What is the small space called that exists between the presynaptic terminal button and the postsynaptic dendritic spine? How wide is it
A
The synaptic gap or synaptic cleft.
Approximately 5 nanometers (nm).
23
Q
What are synaptic vesicles, and where are they found?
A
Synaptic vesicles are found in the presynaptic terminal button and package groups of chemicals called neurotransmitters.
24
Q
What is the role of neurotransmitters in synaptic transmission?
A
Neurotransmitters are released from the presynaptic terminal button, travel across the synaptic gap, and bind to receptor sites on the postsynaptic spine to activate ion channels.
25
How do sensory neurons, motor neurons, and interneurons work together?
Sensory neurons receive information, interneurons process that information and plan responses, and motor neurons execute those responses through movement.
26
Why are interneurons important in the nervous system?
Interneurons are crucial for processing sensory input and coordinating the appropriate responses between sensory and motor neurons.
27
What are the three main categories of neurons? Which are the most common?
Unipolar neurons, bipolar neurons, and multipolar neurons.
The most common are multipolar neurons
28
What is the structure of unipolar neurons, and what is their function?
Unipolar neurons have one neurite (axon) and no dendrites, making them ideal for relaying information forward, such as transmitting physiological information like body temperature to the brain.
29
What type of sensory perception do bipolar neurons facilitate?
Bipolar neurons are involved in sensory perception, such as the perception of light in the retina of the eye.
30
Describe the structure and function of bipolar neurons.
Bipolar neurons have one axon and one dendrite, which help acquire and transmit sensory information to various centers in the brain.
31
What distinguishes multipolar neurons from other types of neurons?
Multipolar neurons have one axon and many dendrites, allowing them to communicate sensory and motor information in the brain.
32
What is one example of a multipolar neuron, and what is notable about its structure?
A prominent example is the pyramidal neuron, which has a triangular or pyramidal shape of its soma.
33
How do multipolar neurons function in the body?
Multipolar neurons communicate sensory and motor information; for instance, their firing can cause muscle contractions.
34
What are glia cells, and how do they differ from neurons?
Glia cells are a second type of cell in the brain that provide support to neurons but do not participate in communication between cells like neurons do.
35
What is the function of oligodendroglia in the nervous system?
Oligodendroglia form the myelin sheaths that insulate axons, facilitating rapid signal transmission.
36
How do oligodendroglia create myelin sheaths?
Oligodendroglia wrap their dendritic processes around the axons of neurons many times to form the myelin sheath.
37
Can one oligodendroglial cell form myelin sheaths for multiple axons?
YES
38
What are microglia and astrocytes?
They are types of glia cells that digest debris from dead neurons, provide nutritional support from blood vessels to neurons, and help regulate the ionic composition of the extracellular fluid.
39
Why are glial cells considered vital for neuronal support?
Glial cells provide essential support functions for neurons, including nutrient transport, debris removal, and maintaining the ionic environment, but they do not engage in direct cell communication like neurons.
40
What is the composition of intracellular and extracellular fluid in neurons similar to? Name some of the keys ions present.
It is similar to salt water.
Sodium (Na+), potassium (K+), chloride (Cl–), and anions (A–).
41
What role do ions play in neuronal function?
Ions are essential for generating and transmitting electrical signals in neurons, influencing actions like action potentials and synaptic transmission.
42
What is electrostatic pressure?
Electrostatic pressure is the force on two ions with similar charge to repel each other and the force of two ions with opposite charge to attract to one another.
43
What is the equilibrium potential?
The equilibrium potential is the voltage at which the force of diffusion is equal and opposite to the force of electrostatic pressure, resulting in no net ion flow.
44
What is the resting membrane potential of a neuron, and what is its typical value?
It is the baseline electrical charge inside the cell compared to the outside, typically around -70 mV.
45
Why is the resting membrane potential negatively charged relative to extracellular fluid?
The resting membrane potential is negatively charged due to the collective drive of several ions that can permeate the cell's membrane, influencing the electrical charge.
46
What does a negative resting membrane potential indicate about the distribution of ions inside and outside the neuron?
A negative resting membrane potential indicates that there is a higher concentration of positive ions (like Na+ and K+) outside the neuron compared to the inside.
47
What role do anions (A–) play in the resting membrane potential?
Anions are highly concentrated inside the cell and contribute to the negative charge of the resting membrane potential; however, they are impermeable to the cell membrane and do not move between compartments because there are no ion channels.
48
What is K+ like at rest?
How do diffusion and electrostatic pressure affect potassium ions (K+) in the neuron?
The cell membrane is very permeable to K+ at rest, but it remains at high concentration inside the cell.
Diffusion pushes K+ outside the cell due to high internal concentration, while electrostatic pressure pulls K+ inside because of the negative charge in the cell, resulting in opposing forces.
49
What is Cl- like at rest?
What happens to chloride ions (Cl–) regarding diffusion and electrostatic pressure in the neuron?
The cell membrane is very permeable to Cl- at rest, but it remains in high concentration outside the cell.
Diffusion pushes Cl– inside the cell due to high external concentration, while electrostatic pressure pushes Cl– outside because of the positive charge outside the cell, creating opposing forces.
50
What are the characteristics of sodium ions (Na+) in relation to the cell membrane at rest?
The cell membrane is not very permeable to Na+, but diffusion pushes Na+ inside due to high external concentration, and electrostatic pressure also attracts Na+ inside because it is attracted to the negative charge within the cell.
Na+ cannot permeate the cell membrane and remains in high concentration outside the cell.
51
Why do sodium ions (Na+) remain in high concentration outside the cell?
Although both diffusion and electrostatic pressure push Na+ inside, Na+ cannot permeate the cell membrane at rest. Small amounts of Na+ inside are removed by the sodium-potassium pump.
52
What is the function of the sodium-potassium pump in neurons?
The sodium-potassium pump uses ATP to remove 3 Na+ ions from the cell in exchange for bringing 2 K+ ions inside, maintaining ion concentration gradients.
53
Who were Hodgkin and Huxley, and what did they study?
Hodgkin and Huxley were scientists who studied the electrical properties of neurons, particularly using the giant axon of the squid, and developed a general model of electrochemical transduction.
They received the Nobel Prize in Medicine in 1963 for their research on neuron function and electrical signaling.
54
What is an action potential?
An action potential is a large, transient electrical current conducted down the axon when the membrane potential becomes more positive than the resting membrane potential.
55
What does the term "all-or-nothing response" mean in relation to an action potential?
An all-or-nothing response means that the action potential either occurs completely or not at all
56
What must happen for an action potential to be triggered?
The membrane potential must reach a specific value called the threshold of excitation, typically around -50 mV, for an action potential to occur.
57
What is depolarization in the context of an action potential?
Depolarization is the change in membrane potential in a more positive direction from the resting state, leading to the initiation of an action potential.
58
How did Hodgkin and Huxley discover the concept of action potentials?
While studying the giant axon of the squid, they observed that applying an electrical stimulus triggered a large, transient electrical current, which they identified as an action potential.
59
What are excitatory postsynaptic potentials (EPSPs)?
EPSPs are depolarizing currents that make the membrane potential more positive, bringing it closer to the threshold of excitation, increasing the likelihood of an action potential.
60
What are inhibitory postsynaptic potentials (IPSPs)?
IPSPs are hyperpolarizing currents that make the membrane potential more negative, moving it further away from the threshold of excitation, decreasing the likelihood of an action potential.
61
How do EPSPs and IPSPs affect the membrane potential?
EPSPs cause depolarization, making the membrane potential more positive, while IPSPs cause hyperpolarization, making it more negative.
62
How does a neuron decide whether to fire an action potential?
A neuron integrates hundreds of inputs, and if the combined effects of EPSPs and IPSPs bring the membrane potential to the threshold of excitation, an action potential is triggered.
63
How do EPSPs and IPSPs interact at a synapse?
PSPs and IPSPs summate or add together in time and space. The combined effect depends on the strength of each individual postsynaptic potential.
64
What happens when two small EPSPs occur at the same time and place?
When two small EPSPs occur simultaneously at the same synapse, they add together to create a larger EPSP.
65
What happens when an EPSP and an IPSP occur at the same time and place?
If an EPSP and an IPSP occur simultaneously at the same synapse, they cancel each other out.
66
How do EPSPs and IPSPs differ from action potentials?
Unlike the all-or-nothing action potential, EPSPs and IPSPs are graded potentials, meaning their strength can vary depending on the input.
67
What is the typical voltage change during an action potential compared to EPSPs and IPSPs?
The voltage change during an action potential is approximately 100 mV, while EPSPs and IPSPs cause voltage changes ranging from 0.1 to 40 mV.
68
How is the strength of EPSPs and IPSPs measured?
The strength of EPSPs and IPSPs is measured by how much the membrane potential diverges from the resting membrane potential.
69
Why are EPSPs and IPSPs called graded potentials?
EPSPs and IPSPs are called graded potentials because their strength varies depending on the magnitude of the input, unlike the all-or-nothing nature of action potentials.
70
What happens when the summation of EPSPs is strong enough to reach the threshold of excitation?
When the summation of EPSPs depolarizes the membrane potential to the threshold of excitation, it initiates an action potential.
71
What happens to the action potential once it is initiated?
The action potential travels down the axon, away from the soma, until it reaches the terminal button at the end of the axon.
From there, it releases neurotransmitters into the synaptic cleft.
Neurotransmitters bind to ionotropic receptors on the postsynaptic dendritic spines, causing ion channels to open and allowing ions to enter or exit the cell.
72
What determines whether an EPSP or IPSP occurs in the postsynaptic cell?
The type of neurotransmitter released and the permeability of the ion channel it activates will determine whether an EPSP (excitatory) or IPSP (inhibitory) occurs in the postsynaptic cell.
73
How do EPSPs and IPSPs in the postsynaptic cell influence the next action potential?
EPSPs and IPSPs in the postsynaptic cell summate, and if the overall depolarization reaches the threshold of excitation, the entire process begins again in the next cell.
74
How do ionotropic receptors work?
Ionotropic receptors are ion channels that open when a specific neurotransmitter binds to them, allowing ions to enter or exit the cell, influencing whether an EPSP or IPSP occurs.
75
Which ions are involved in generating the action potential?
Sodium (Na+) and potassium (K+) are the primary ions involved in generating the action potential.
76
What happens to ion channels when a neuron reaches the threshold of excitation?
Voltage-dependent Na+ channels open, allowing Na+ to rush into the cell, causing depolarization.
77
Why does Na+ rush into the cell when voltage-dependent Na+ channels open?
Both diffusion and electrostatic pressure push Na+ inside the cell, which causes the cell to become more positively charged (depolarized).
78
What is the peak membrane potential during the depolarization phase of the action potential?
The inside of the cell becomes very positively charged, reaching approximately +40 mV.
79
What happens to the Na+ channels after the peak of the action potential?
The Na+ channels close and become refractory, meaning they cannot reopen until the cell returns to its resting membrane potential.
80
What is the refractory period, and what is its function?
The refractory period is a time when Na+ channels cannot reopen, preventing a new action potential from occurring and ensuring the action potential moves in one direction down the axon.
81
What happens when the cell becomes highly depolarized?
Voltage-dependent K+ channels open, allowing K+ to exit the cell, causing the cell potential to return to its resting state (repolarization).
82
What causes the brief hyperpolarization after the action potential?
Hyperpolarization occurs due to the gradual closing of K+ channels and the continued movement of K+ out of the cell by electrostatic pressure and the sodium-potassium pump.
83
How long does the exchange of Na+ and K+ during an action potential take?
The exchange of Na+ and K+ ions occurs very rapidly, in less than 1 millisecond.
84
How does the action potential propagate along the axon?
The action potential moves in a wave-like motion down the axon until it reaches the terminal button.
85
What is the function of myelin on axons?
Myelin insulates axons, speeding up the transmission of action potentials.
86
What are the gaps in myelin sheaths along an axon called?
The gaps in myelin sheaths are called nodes of Ranvier.
87
How does myelin save energy during action potential transmission?
Myelin prevents ion flow under its covering, reducing the need for ATP to maintain the resting membrane potential between the nodes of Ranvier.
88
What happens to the action potential under the myelin?
The action potential degrades slightly under the myelin but remains strong enough to trigger a new action potential at the next node of Ranvier.
89
What is saltatory conduction?
Saltatory conduction is the process by which the action potential jumps from one node of Ranvier to the next, speeding up transmission.
90
Why is saltatory conduction more efficient than continuous conduction?
Saltatory conduction is faster and requires less energy because ion exchange occurs only at the nodes of Ranvier, not along the entire axon.
91
How do neurotransmitters interact with receptors in the postsynaptic cell?
Neurotransmitters bind to specific receptor subtypes in a lock-and-key fashion, triggering the opening of ion channels.
92
What types of ions are involved in excitatory postsynaptic potentials (EPSPs)?
EPSPs occur when neurotransmitters open Na+ or Ca+ channels, allowing these positively charged ions to enter the cell.
93
What neurotransmitter is associated with excitatory postsynaptic potentials (EPSPs)?
Glutamate is the main excitatory neurotransmitter in the brain, activating NMDA receptors to cause EPSPs.
94
What types of ions are involved in inhibitory postsynaptic potentials (IPSPs)?
IPSPs occur when neurotransmitters open Cl- or K+ channels, allowing these ions to enter or leave the cell and make the membrane more negative.
95
What neurotransmitter is associated with inhibitory postsynaptic potentials (IPSPs)?
amma-aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the brain, activating GABA receptors to cause IPSPs.
96
What happens to neurotransmitters that do not bind to receptors in the postsynaptic cell?
Unused neurotransmitters are either broken down by enzymes, inactivated by glial cells, or taken back into the presynaptic terminal button through reuptake.
97
What current causes depolarization, increasing the likelihood that the neuron will fire?
inhibitory postsynaptic potential.
inhibitory presynatic potential.
neutralized presynatic potential.
excitatory presynaptic potential.
excitatory postsynaptic potential
excitatory postsynaptic potential
98
How do hormones differ from neurotransmitters in their method of signaling?
Unlike neurotransmitters, which are released near their target cells, hormones are secreted into the bloodstream and affect cells throughout the body that have receptors for them
In other words neurotransmitters have localized effects, while hormones have widespread effects throughout the body.
99
How do the speed and duration of hormone effects compare to neurotransmitters?
Hormones are slower to take effect than neurotransmitters but tend to have longer-lasting effects.
100
How are hormones ultimately controlled in the body?
Hormones are controlled through interactions between the hypothalamus (in the central nervous system) and the pituitary gland (in the endocrine system).
101
What are hormones involved in regulating?
Hormones regulate various bodily functions, such as growth, metabolism, reproduction, and mood.
102
Why is the interaction between the hypothalamus and pituitary gland important?
This interaction helps coordinate the endocrine system’s control over hormone release throughout the body.
103
Where is the pituitary gland located?
The pituitary gland is located at the base of the brain, descending from the hypothalamus.
104
Why is the pituitary gland referred to as the "master gland"?
It is called the "master gland" because its messenger hormones control all the other glands in the endocrine system, mainly following instructions from the hypothalamus.
105
What types of hormones does the pituitary gland secrete?
The pituitary gland secretes growth hormone, endorphins for pain relief, and various key hormones that regulate fluid levels in the body.
106
How does the pituitary gland interact with the hypothalamus?
The pituitary gland acts in close association with the hypothalamus, carrying out its instructions primarily through messenger hormones.
107
What is one function of endorphins secreted by the pituitary gland?
Endorphins act as natural pain relievers in the body.
108
Where is the thyroid gland located?
The neck
109
What are the main functions of the hormones released by the thyroid gland?
The thyroid hormones regulate growth, metabolism, and appetite.
110
What is hyperthyroidism?
Hyperthyroidism is a condition where the thyroid gland secretes too much thyroxine, leading to symptoms like agitation, bulging eyes, and weight loss.
One common cause of hyperthyroidism is Graves’ disease, which is an autoimmune disease.
111
What are the symptoms of hypothyroidism?
Symptoms of hypothyroidism include tiredness and a frequent feeling of being cold.
112
How can thyroid disorders be treated?
Thyroid disorders are often treatable with medications that help reestablish a balance in the hormones secreted by the thyroid.
113
What hormones do the adrenal glands secrete that are involved in the stress response?
The adrenal glands secrete hormones such as epinephrine (adrenaline) and norepinephrine (noradrenaline).
114
What is the primary function of the pancreas in relation to hormones?
The pancreas secretes hormones that regulate blood sugar levels, specifically insulin and glucagon.
115
How does insulin affect blood sugar levels?
Insulin lowers blood glucose levels.
116
What role does glucagon play in blood sugar regulation?
Glucagon raises blood glucose levels.
117
Why do people with diabetes need to manage their insulin levels?
People with diabetes do not produce enough insulin, so they must take medications that stimulate or replace insulin production and closely control their sugar and carbohydrate intake.
118
What role do the gonads play in the body?
The gonads secrete hormones related to sexuality, sex, reproduction, and associated physical and behavioral phenomena.
119
What are the two types of gonads, and where are they located?
The two types of gonads are ovaries (usually tied to femaleness) and testes (usually tied to maleness).
120
What hormones are secreted by the gonads?
The gonads secrete estrogens (e.g., estradiol), progesterone, and androgens (e.g., testosterone).
121
Which gonads typically secrete more androgens?
The testes typically secrete more androgens than the ovaries do.
122
How does hormone secretion differ between ovaries and testes?
The ovaries exhibit more monthly cyclicity during reproductive age, correlating with menstrual cycles, while the testes do not have this cyclic pattern.
123
What hormones are associated with the pituitary gland, and what is its function?
The pituitary gland secretes growth hormone and releasing/inhibiting hormones (e.g., thyroid-stimulating hormone) to regulate growth and hormone release
124
What hormones does the thyroid gland produce, and what is its primary function?
The thyroid gland produces thyroxine and triiodothyronine, which regulate metabolism and appetite.
125
What hormone is secreted by the pineal gland, and what does it regulate?
The pineal gland secretes melatonin, which regulates biological rhythms such as sleep cycles.
126
What hormones are produced by the adrenal glands, and what is their function?
The adrenal glands produce epinephrine and norepinephrine, which are involved in the stress response and increase metabolic activities.
127
What hormones are secreted by the pancreas, and what is their role?
The pancreas secretes insulin and glucagon to regulate blood sugar levels.
128
Which hormones do the ovaries and testes produce, and what functions do they serve?
The ovaries and testes produce estrogen, progesterone, and androgens (e.g., testosterone), mediating sexual motivation, behavior, and reproduction.
129
What are anabolic steroids and how do they relate to athletic performance?
Anabolic steroids are drugs that mimic the effects of the body's own steroid hormones, like testosterone. They are believed to enhance athletic performance by increasing muscle mass, strength, and endurance
130
Why are anabolic steroids banned in many professional sports?
Anabolic steroids are banned because they are considered performance-enhancing drugs (PEDs) that provide an unfair competitive advantage and pose significant health risks.
131
What are some potential benefits of anabolic steroid use for athletes?
Potential benefits include increased muscle mass, enhanced strength, and improved endurance.
132
What are some risks associated with anabolic steroid use?
Risks include a range of negative outcomes, from cosmetic issues like acne to life-threatening conditions such as heart attacks.
133
How can anabolic steroid use affect mood?
Use of anabolic steroids can lead to profound changes in mood and may increase aggressive behavior.
134
The ________ secretes hormones that regulate the body’s fluid levels.
pituitary
135
How do psychoactive drugs function (very briefly)
They change someones mood or the way they feel by interfering or altering with how neurons communicate with each other
136
What is the primary distinction between agonists and antagonists in relation to neurotransmitter activity?
Agonists increase activity at the synapse, while antagonists reduce activity at the synapse.
137
How do psychoactive drugs interact with neurotransmitters?
Psychoactive drugs can either enhance (agonists) or inhibit (antagonists) neurotransmitter activity, affecting mood, perception, and behavior.
138
What is the role of specific circuits in the brain regarding neurotransmitter release?
Neurons that release neurotransmitters are typically localized within specific brain circuits that mediate particular behaviors or functions.
139
What are some potential outcomes of drugs that act as agonists?
Agonists may enhance feelings of pleasure, reduce pain, or improve mood by increasing neurotransmitter activity.
140
What might be the effects of drugs that act as antagonists?
Antagonists can block or dampen neurotransmitter activity, potentially leading to effects such as reduced mood or increased anxiety.
141
Why are certain neurotransmitters particularly important in psychopharmacological treatments?
They are involved in regulating mood, anxiety, cognition, and various other psychological processes, making them targets for therapeutic interventions.
142
Can you give an example of an agonist and its effect?
An example of an agonist is morphine (trade name), which acts as a pain reliever by enhancing the effects of endogenous opioids.
143
Can you give an example of an antagonist and its effect?
An example of an antagonist is naloxone (trade name), which blocks opioid receptors to reverse opioid overdoses.
144
Why is it important to understand that drugs can affect multiple neurotransmitters?
Understanding that drugs can affect multiple neurotransmitters is crucial because it explains the range of side effects that may occur when taking a particular drug.
145
Do psychotropic drugs work exclusively on one neurotransmitter?
No, no currently available drugs work exclusively on one specific neurotransmitter; they can have effects on multiple neurotransmitter systems.
146
What is a common consequence of a drug affecting multiple neurotransmitters?
A common consequence is the development of side effects, which can be significant enough for individuals to stop taking the medication.
147
What might individuals need to do if they experience side effects from a prescribed psychotropic drug?
Individuals may need to take additional medications to reduce the side effects caused by the initial psychotropic drug.
148
What does the term "psychotropic drug" refer to?
Psychotropic drugs refer to medications that affect mood, perception, cognition, and behavior by altering neurotransmitter activity in the brain.
149
What does pharmacokinetics refer to?
Pharmacokinetics refers to how the body handles a drug, including absorption, distribution, metabolism, and excretion.
150
What is the most common route of drug administration?
Oral administration.
151
Why is oral administration often considered variable and complex?
The absorption rate can be affected by factors such as the quantity and type of food in the stomach.
152
What influences the rate of absorption for orally administered drugs?
Factors include the type of food consumed (e.g., fats vs. proteins) and the presence of other substances in the stomach.
153
Why might some drug labels specify foods to avoid when taking the medication?
Certain foods can significantly affect the rate of absorption of the drug.
154
What are two of the most rapid routes of drug administration?
Inhalation (e.g., smoking, gaseous anesthesia) and intravenous (IV) administration.
Both can deliver drugs to the brain in less than 10 seconds.
155
What is a major risk associated with intravenous (IV) drug administration?
It is the most dangerous route because adverse drug reactions can occur quickly, leaving little time to administer antidotes.
156
Why is IV administration particularly concerning in cases of overdose, such as with heroin?
In the event of an overdose, the rapid onset of effects leaves very little time for medical intervention.
157
Why is the speed at which a drug reaches the brain important?
The faster a drug activates the brain's reward circuits, the higher the risk for abuse and addiction.
158
What type of drugs are considered to have a high risk for abuse?
Psychostimulants like amphetamine and cocaine.
159
Why do amphetamines and cocaine have a high potential for addiction?
They act as agonists at dopamine (DA) neurons involved in the reward system and can be administered in forms that allow rapid delivery to the brain (e.g., smoking or injecting).
160
What complicates the addiction to cigarette smoking?
The rapid delivery of nicotine to the brain and its indirect effects on dopamine neurons.
161
What happens to cues associated with drugs that reach the brain quickly?
The cues can also become addictive, causing cravings that lead to relapse when encountered.
162
Give an example of cues that might trigger cravings for crack users and cigarette smokers.
For crack users, it could be the pipe used to smoke; for smokers, it could be finishing dinner or waking up in the morning.
163
Why is relapse a significant risk for individuals in drug treatment programs?
Returning to old environments or being around old friends can trigger cravings associated with previous drug use.
164
How is avoiding certain situations more difficult for cigarette smokers compared to other drug users?
Cigarette smokers cannot avoid daily activities like eating or waking up, which can trigger cravings.
165
Where does the metabolism of psychoactive drugs primarily occur?
In the liver.
166
What role do enzymes play in drug metabolism?
Enzymes catalyze chemical reactions that break down psychoactive drugs.
167
What is the cytochrome P450 superfamily?
A family of enzymes that break down many psychoactive drugs.
168
Why is there not a unique enzyme for each psychoactive drug?
Certain enzymes can break down a wide variety of drugs.
169
What is drug tolerance?
A condition where repeated exposure to a drug produces less of an effect over time, requiring more of the drug to achieve the same effect.
170
Which types of drugs are particularly known for causing tolerance?
Sedative drugs like alcohol and opiate-based painkillers.
171
What is metabolic tolerance?
A type of tolerance that occurs when the liver becomes more efficient at breaking down a drug.
172
What does enzyme induction mean?
It refers to the increase in the production of enzymes in the liver, which can lead to faster breakdown of certain drugs.
173
How does chronic drinking affect alcohol metabolism?
Chronic drinking causes alcohol to be broken down more quickly, leading to the need for higher consumption to achieve the same effect.
174
What are potential consequences of excessive alcohol consumption on the liver?
Damage can occur, leading to conditions such as fatty liver or cirrhosis.
175
What is a well-known food that affects drug metabolism?
Grapefruit juice.
176
How does grapefruit juice affect cytochrome P450 enzymes?
It suppresses these enzymes, which normally break down a variety of drugs in the liver.
177
What can happen if cytochrome P450 enzymes are suppressed by grapefruit juice?
Drug levels can build up to potentially toxic levels in the body.
178
How long can the effects of grapefruit juice on drug metabolism persist?
The effects can last for extended periods of time after the consumption of grapefruit juice.
179
Name a psychotropic drug that is likely to interact with grapefruit juice.
Carbamazepine (Tegretol), diazepam (Valium), or fluvoxamine (Luvox).
180
What is diazepam (Valium) used to treat?
Anxiety, alcohol withdrawal, and muscle spasms.
180
What conditions is carbamazepine (Tegretol) prescribed for?
Bipolar disorder.
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What conditions does fluvoxamine (Luvox) target?
Obsessive-compulsive disorder and depression.
182
What challenges do individuals face when prescribed antidepressants?
Many do not respond to the first antidepressant and may need to try different drugs before finding one that works.
183
What are the four categories of drug metabolizers in the general population?
The four categories are:
1. Ultra-extensive metabolizers
2. Extensive metabolizers
3. Intermediate metabolizers
4. Poor metabolizers
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What could be the consequence for an ultra-extensive metabolizer prescribed an antidepressant?
They may metabolize the medication too quickly for it to be effective.
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What might happen to a poor metabolizer taking the same antidepressant?
They may accumulate high levels of the drug, leading to side effects and negative outcomes.
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How can genetic testing improve antidepressant prescriptions?
Genetic tests can determine a patient's metabolizer category, allowing for more informed dosing decisions.
However, the test is expensive and not commonly covered by health insurance plans.
187
How fast do extensive and intermediate metabolizers break down drugs?
extensive metabolizers are also able to break down drugs fairly quickly
intermediate metabolizers break down drugs more slowly than extensive metabolizers
188
What population is often excluded from clinical trials for psychotropic drugs? Why?
The elderly population is often excluded from these trials.
clinical trials often exclude people with multiple comorbidities (other diseases, conditions, etc.), which are typical for elderly populations
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What is polypharmacy?
Polypharmacy refers to the use of multiple drugs, which is common among elderly populations.
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Why might elderly individuals be at a higher risk when it comes to psychotropic drug prescriptions?
Because they typically have multiple health conditions and consume a significant proportion of prescription medications.
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How does drug metabolism change in elderly populations?
Drug metabolism is often slowed considerably, meaning less drug can produce the same effect.
192
What is a common risk associated with elderly individuals taking psychotropic medications?
One of the greatest risks is falling, which can lead to breaking bones due to dizziness from excessive drug effects.
193
How can psychotropic medications impact bone health in the elderly?
Psychotropic medications can reduce bone density, worsening the consequences of falls.
Falls can result in serious injuries, such as broken bones.
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Which of the following is best described as the major excitatory neurotransmitter in the brain and has an important impact on learning?
Serotonin.
Dopamine.
Norepinephrine.
Acetylcholine.
Glutamate
Glutamate
