exam 1 study questions

Question 1

what is meant by the distribution of a drug

Answer 1

The process of delivering a drug from the bloodstream to the tissues of the body
Factors that can affect the distribution of a drug
Lipid solubility, molecular size, degree of ionization, cellular binding, duration of action, therapuetic effects, toxic effects
Vascularity, transport mechanisms, blood barriers, plasma binding proteins, free and bound forms of drugs, drug interaction, disease states, drug reservoirs, volume of distribution

Question 2

how is a drugs solubility in fat tissue likely to affect the pharmacokinetics of a drug

Answer 2

Drugs that dissolve in fat tend to concentrate in fattty tissues.
Absorbed more rapidly than non-lipid soluble drugs

Question 3

why is the cytochrome p450 system of enzymes important

Answer 3

Cytochrome P450 enzymes are essential for the metabolism of many medications. Although this class has more than 50 enzymes, six of them metabolize 90 percent of drugs
Genetic variability in these enzymes may influence a patients response to commonly prescribed drug classes
Cytochrome p450 enzymes can be inhibited or induced by drugs, resulting in clinically significant drug interactions
Essential for the production of cholesterol, steroids and prostacyclins
They are also necessary for the detoxification of foreign chemicals and the metabolism of drugs
They are bound to membranes within a cell, and contain a heme pigment that absorbed light
Predominately expressed in the liver

Question 4

first pass effect

Answer 4

In which a drug gets metabolized at a specific location in the body that results ina reduced concentration of the active drug upon reaching its site of action or the systemic circulation
Often associated with the liver, as this is the major site of drug metabolism.

Question 5

active metabolite

Answer 5

An active form a drug after it has been processed by the body
When a drug is metabolized by the body into a modified form, which continues to produce effects in the body, usually these effects are similar to those of the parent drug but weaker

Question 6

half life and metabolism

Answer 6

Half-life is influenced by drug distribiution, drug metabolism, and drug excretion, each of which can be influenced by many factors such as age, use of concurrent medications, and presence of liver or renal disease
A steady state is reached when the quantity of drug eliminated in the unit of time equals the quantity of the drug that reaches the systemic ciculation in the unit of time → takes somewhere between 5 to 6 half-lives

Question 7

routes for drug elimination

Answer 7

The major route for most drugs are the kidneys → particularly for water soluble drugs
Other exaples include the urine, bile, sweat, saliva, tears, milk, and stool
The most important excretory organs are the kidney and liver
In the kidney the excretion of drugs depends on glomerular filtration, active tubular secretion, and passive tubular absorption

Question 8

why would one want to measure drug concentration in the blood

Answer 8

The drug concentration in the blood can give clues to whether or not the drug is working for an individual
Can make sure that drug concentrations can be maintained within a target range

Question 9

what factors determine the clearance of a drug

Answer 9

Can be influenced by age and disease
A reduction in drug clearance is associated with an increase in the half-life of a drug and vice versa

Question 10

receptor theory

Answer 10

A drug receptor is a specialized target macromolecule that binds to a drug and mediates its pharmacological action. These receptors may be enzymes, nucleic acids, or specialized membrane bound proteins

Question 11

tolerance

Answer 11

refers to the body getting used to taking a substance and requiring higher doses

Question 12

dependence

Answer 12

refers to the physical or psychological symptoms that occur that make someone feel like they must continue taking a substance

Question 13

reverse tolerance

Answer 13

Sensitization
Which following repeated exposure to the same dose of a particular drug, a specific behavioral, physiological, or cellular response increases

Question 14

pH effects

Answer 14

Diffusion through lipid and aqueous solutions will be slightly different, depending on drug properties
Dissociated drugs, those components do not readily cross the cell membranes, as long as the drug remains associated it is more likely to cross the membrane. What causes dissociation?
Weak acid - the more acidic the solution that the weak acid is in, the more associated it is going to be. A weak acid like aspirin is readily absorbed across the stomach wall and into the blood stream, if the gastric juice was more basic then the aspirin would dissociate.
Weak base - you would have very little absorbed in the stomach due to dissociation
Blood pH is roughly neutral → doesn’t really change
Can manipulate the pH of urine
If we have a drug that is in the bloodstream and it crosses into the urine, if it was a weak acid, if you make the urine more basic the weak acid would dissociate and be trapped in the urine to be excreted. If the urine would be more acidic, the weak acid would stay associated and would move into the bloodstream.

Question 15

central dogma of molecular biology

Answer 15

An explanation of the flow of genetic information within a biological system

Question 16

how are proteins programmed

Answer 16

Each protein is coded for by a specific section of DNA called a gene. A gene is the section of DNA required to produce one protein

Question 17

one gene-one enzyme hypothesis

Answer 17

Proposed by george beadlie in 1941, the theory that each gene directly produces a single enzyme which consequently affects and individual step in a metabolic pathway

Question 18

enzymes

Answer 18

proteins that help speed up metabolism or the chemical reactions in our bodies. They build some substances and break others down.

Question 19

importance of protein

Answer 19

Protein binding influences the bioavailability and distribution of active compounds, and is a limiting factor in the passage of drugs across biological membranes and barriers
Extensive plasma protein binding will increase the amount of drug that has to be absorbed before effective therapeutic levels of unbound drugs are reached.
Elimination of a highly bound drug may be delayed

Question 20

pharmacogenetics

Answer 20

A field of research that studies how a person’s genes affect how they respond to medications. Its long term goal is to help doctors select the drugs and doses best suited for each person

Question 21

cellular components of the nervous system

Answer 21

The nervous system is made up of neurons, specialized cells that can receive and transmit chemical or electrical signals, and glia, cells that provide support functions for the neurons by playing an information processing role that is complementary to neurons
The nervous system has three main functions: sensory input, integration of data and motor output.
Structure of a neuron = dendrites are tree-like structures that extend away from the cell body to receive messages from other neurons and specialized junctions called synapses. Once a signal is received by the dendrite, it then travels to the cell body
Types of glial cells → astrocytes, microglia, oligodendrocytes, schwann cells, radial glial

Question 22

What roles do sodium and potassium channels have in the generation and form of the action potential?

Answer 22

The sodium potassium pump is an information processing element in brain computation
Brain neurons can transmit using a flow Na+ and K+ ions, which produce an electrical spike called an action potential. The Na/K pump uses the energy of one ATP molecules to exchange three intracellular Na+ ions for two extracellular K+ ions.
As the concentration of sodium in the extracellular solution is reduced, the action potentials become smaller
As the action potential passes through, potassium channels stay open a little bit longer and continue to let positive ions exit the neuron. This means that the cell temporarily hyperpolarizes

Question 23

Explain the organization and function of neurons, including the dendrites and the axon.

Answer 23

Function is to send electrical impulses and chemical signals to and from the brain
Dendrites receive messages from other neurons
Other parts include the cell body which contains a nucleus and cytoplasm, as well as the axon which transmits information away from the nucleus,

Question 24

Reuptake

Answer 24

is necessary for normal synaptic physiology because it allows for the recycling of neurotransmitters and regulates the level of the neurotransmitter present in the synapse, thereby controlling how long a signal resulting from neurotransmitter release lasts.
Reuptake is what happens after a signal is transmitted
An ideal drug would be a drug that could either speed up or inhibit the reuptake in order to control the level of neurotransmitter that was present in the synapse

Question 25

Enzymatic degradation occurs in two stages:

Answer 25

absorption of enzymes on the polymer surface followed by hydrolysis of the bonds

Question 26

fates of a neurotransmitter after it is released into a synapse.

Answer 26

Can be broken down by enzymes
Reabsorbed by the terminal buttons

Question 27

What are the differences between a receptor coupled to an ion channel and one coupled to a series of second messengers?

Answer 27

The ion-channel-coupled receptors, also called ligand-gated ion channels are one of the three main types of cell membrane receptor. They play an important role in the transmission of neuronal signals at the synapses
Second messengers are intracellular signaling molecules released by the cell in response to exposure to extracellular signaling molecules - the first messengers
Trigger physiological changes at the cellular level

Question 28

Describe the similarities and differences of agonists, antagonists, and partial agonists.

Answer 28

Drugs with both affinity (they bind to the target receptor) and intrinsic efficacy (they change receptor activity to produce a response)
Antagonists have affinity but zero intrinsic efficacy, therefore they bind to the target receptor but do not produce a response
Partial agonists are drugs that binds to and activate a given receptor but have only partial efficacy at the receptor

Question 29

Identify drugs that block the action of acetylcholine as a neurotransmitter. What are the consequences of the blockade?

Answer 29

Following dissociation from the receptor, the ach is rapidly hydrolyzed by the enzyme acetylcholinesterase
Drugs that inhibit ach breakdown are effective in altering cholinergic neurotransmission
Blocking acetylcholine signals can decrease involuntary muscle movement, digestion, mucus secretion

Question 30

Name three catecholamine neurotransmitters. How are these transmitters made and how is the neurotransmitter actions of these substances terminated?

Answer 30

Dopamine - also a neurohormone released by the hypothalamus in your brian
Dopamine interacts with specific membrane receptors to produce its effects, these effects are terminated by the re-uptake into the presynaptic neuron by a dopamine transporter
Noradrenaline - made from nerve cells in the brainstem
Terminated through inactivation of MAO enzymes, repptake
Function is to increase heart rate
Adrenaline - function terminated by the breakdown of comt or MAO
All are made by your adrenal gland

Question 31

The Food and Drug Administration

Question 32

Researchers may discover new drugs through:

Question 33

The structure at the most caudal end of the brain stem is the

Question 34

One way in which myelin-producing cells in the central nervous system (CNS) differ from ones that
produces myelin in the peripheral nervous system is that in the CNS

Question 35

Enzymes serve

Question 36

The Na+/K+ pump helps to maintain the resting membrane potential by moving __________ Na+
ion(s) out of the cell and __________ K+ ion(s) into the cell.

Question 37

The axon hillock is

Question 38

The Na+/K+ pump helps to maintain the ___________ by moving Na+ ions out of the K+ ions into the
cell.

Question 39

Neurotransmitters that open ion channels by involving a G protein do so by binding to which type
of the following receptors?

Question 40

While __________ describes how the body distributes and excretes drugs, ________ describes how
drug molecules interact with their targets.

Question 41

The first-pass effect occurs when drugs are taken or given

Question 42

If one wants to increase excretion of a metabolite that is a weak acid, one can

Question 43

Most neurons communicate with one another by:

Question 44

As proposed by the “Central Dogma of Molecular Biology,” the step involving the transfer of
information from RNA to protein is called

Question 45

A slowly developing decreased responsiveness to a drug is

Question 46

The blood-brain barrier is primarily the result of

Question 47

Saltatory conduction

Question 48

What is a place where drug is taken up, held and slowly released into the blood?

Question 49

Postsynaptic receptors

Question 50

The cell membrane consists of

Question 51

After drug administration has occurred, the amount of drug in the blood that is free to bind at
specific target sites is referred to as

Question 52

Which factor is not considered when considering the pharmacokinetics of a drug?

Question 53

Drugs administered _______ have the most rapid onset of action.

Question 54

Agents that induce developmental abnormalities in a fetus are known as

Question 55

While drugs can be excreted from the body by several routes, the most important route of
elimination is through the

Question 56

After chronic use, the need to administer more of a drug to achieve the same drug effect is known
as

Question 57

Neurons rely on _______ for protection, metabolic support, and insulation.