FM0 - Alon

What is the lipid bilayer mainly composed of?

Phospholipids

To which types of molecules is the lipid bilayer permeable?

Small and lipophilic molecules

What is passive or simple diffusion?

The movement of a substance from high to low concentration via the lipid bilayer

What is facilitated diffusion?

The movement of a substance from high to low concentration via a carrier protein

What is primary active transport?

A process where ATP hydrolysis provides the energy to move a substance from low to high concentration

How does the Na+/K+ pump function?

It moves 3 Na+ ions out of the cell for every 2 K+ ions moved in

What is secondary active transport (cotransport)?

A process where one substance moving down its concentration gradient provides energy to move another substance against its concentration gradient

What is the difference between symport and antiport?

Symport moves 2 substances in the same direction; antiport moves 2 substances in opposite directions

What is exocytosis?

The process where a cell releases material into the extracellular environment by vesicle fusion with the plasma membrane

What is endocytosis?

The process where a cell absorbs materials from the extracellular environment by vesicle fusion with the plasma membrane

Name the three types of endocytosis and their specific characteristics.

Phagocytosis

What is transcytosis?

A combination of receptor-mediated endocytosis and exocytosis used to move a substance across a cell

How does oral rehydration therapy work?

Sodium and glucose are transported via intestinal epithelial cells into the blood, causing water to follow

How do sex, body composition, and age affect total body water?

Sex

What is the difference between osmotic pressure and oncotic pressure?

Osmotic pressure is the pressure required to prevent osmosis from low to high solute concentration across a semipermeable membrane. Oncotic pressure is osmotic pressure generated specifically by proteins in plasma

Compare osmolarity and osmolality.

Osmolarity is the number of solute molecules per volume of solvent (mOsmol/L). Osmolality is the number of solute molecules per weight of solvent (mOsmol/kg)

Describe the effects of isotonic, hypertonic, and hypotonic solutions.

Isotonic

How are the concentrations of Na+, K+, and Cl− distributed across ICF and ECF?

Na+ and Cl− are higher in ECF; K+ is higher in ICF

How is the Na+/K+ gradient established?

It is maintained by the Na+/K+ pump

What is the formula and normal value for plasma osmolality?

Formula

What happens to plasma osmolality and cell size when a large volume of water is consumed?

Drinking large volumes of water leads to decreased plasma Na+, decreased osmolality, and water moving into cells, causing them to increase in size

Compare the source and function of vasopressin and aldosterone.

Vasopressin

What is an osmolal gap?

The difference between calculated osmolality and measured osmolality in a lab. If the gap is greater than 10 mOsm/kg, it indicates the presence of an unknown osmotically active substance, such as alcohol

What is an anion gap?

The difference between major cations and anions in plasma, calculated as Na+ − (HCO3− + Cl−). An anion gap greater than 11 mOsm/L suggests an unknown anion, such as lactate, is present

What is homeostasis?

The maintenance of a stable internal environment despite changes in the external environment

What are the roles of the sensor, control centre, and effector in homeostasis?

Sensor

What distinguishes the stop mechanism of a negative feedback loop from that of a positive feedback loop?

A negative feedback loop has a setpoint and stops itself once the setpoint is reached, whereas a positive feedback loop lacks a setpoint and continues until an external factor stops it

What is feedforward control?

A regulatory mechanism where a response is decided by the control centre and carried out by an effector before the sensor detects any change in a variable

What is endocrine signalling?

A process where a ligand is released by a cell and transported via the blood to act on a distant cell. It is performed by hormones to achieve various functions, such as insulin causing cells to take up glucose

What is autocrine signalling?

A signalling process where a ligand released by a cell acts on the same cell. It is mediated by cytokines and growth factors and functions in cell growth and differentiation

Where do steroid hormones versus protein and peptide hormones bind?

Steroid hormones bind to intracellular receptors; protein and peptide hormones bind to surface receptors

How does the speed of neural signaling compare to other forms of signaling?

Neural signaling is faster than other forms of signaling

Where are the concentrations of Na+, Cl−, and Ca2+ higher relative to a resting cell?

These ions have higher concentrations outside the cell

What defines the equilibrium potential of an ion?

It is the membrane potential where the chemical and electrical forces acting on the ion are balanced, assuming 100% permeability

Why is the resting membrane potential (RMP) approximately −70 mV?

The cell is highly permeable to K+ and there is a steady leak of Na+ into the cell

Which statement correctly describes the kinetics of voltage-gated ion channels?

Na+ channels are fast, and K+ channels are slow

What is the result of the all-or-none property of action potentials?

If the threshold potential is not reached, no action potential occurs. If the threshold is reached, an action potential occurs

What is the difference between absolute and relative refractory periods?

Absolute refractory period

What is myelin and what is it made of?

Myelin is a layer of glial cells around an axon. In the PNS, it is composed of Schwann cells; in the CNS, it is composed of oligodendrocytes

What is the primary function of myelin?

It increases the speed of action potential conduction, specifically via saltatory conduction where the action potential jumps between nodes of Ranvier containing high concentrations of voltage-gated Na+ and K+ channels

List the common locations for a synapse.

Dendrites; soma; axon hillock; axon terminal

Describe the steps of synaptic transmission.

AP arrives at presynaptic axon terminal; voltage-gated Ca2+ channels open; Ca2+ enters cell; Ca2+ induces fusion of neurotransmitter vesicles with presynaptic membrane; exocytosis; NT binds to postsynaptic membrane; postsynaptic action occurs; termination of NT action; repackaging of NT into vesicles

Are small molecule neurotransmitters fast-acting or slow-acting?

They are fast-acting

Give examples of small molecule and large molecule neurotransmitters.

Small molecule NTs

How does the synthesis of small molecule neurotransmitters differ from large molecule neurotransmitters?

Small

What is the difference between excitatory and inhibitory postsynaptic actions?

Excitatory

What are ionotropic and metabotropic postsynaptic actions?

Ionotropic

What are the ways to terminate neurotransmitter action?

Uptake by glial cells; diffusion; enzymatic breakdown; reuptake by presynaptic cell; uptake by postsynaptic cell

What is the neuromuscular junction (NMJ) and why is it special?

It is a synapse between a motor neuron and skeletal muscle that involves the release of acetylcholine (ACh). It is highly specialized because an action potential always leads to muscle contraction

What are two types of drugs that terminate neurotransmitter action?

Enzyme inhibitors and reuptake inhibitors

What kind of drugs affect neurotransmitter repackaging into vesicles?

Vesicular monoamine transporter inhibitors

What is myasthenia gravis?

An autoimmune disorder where antibodies for postsynaptic ACh receptors are created

Define pharmacodynamics.

The study of what the drug does to the body

List the four main drug targets.

Enzymes; carrier proteins; ion channels; receptors

How does acetylsalicylic acid work as a drug?

It inhibits the cyclooxygenase enzyme to prevent prostaglandin formation

What is the mechanism of action for malathion?

It inhibits acetylcholinesterase to increase ACh levels

How does α-methyldopa act as a false substrate?

It acts as a substrate for DOPA decarboxylase instead of norepinephrine, which lowers blood pressure

What is a prodrug?

A drug that is converted into its active form by an enzyme

What is the primary function of ABC transporters in cells?

They pump foreign substances out of cells, which is implicated in drug resistance

What are the four main types of receptors that serve as drug targets?

Ligand-gated ion channels; G-protein coupled receptors (GPCRs); enzyme-linked receptors; intracellular (cytoplasmic/nuclear) receptors

How is potency defined in pharmacology?

The amount of drug needed to achieve a specific effect

How is drug efficacy defined?

The maximum possible response a drug can produce

What is ED50?

The dose required to produce 50% of the maximum desirable response

What is an agonist?

A drug that binds to a receptor and mimics the response of an endogenous substance

How do full agonists and partial agonists differ in response?

Full agonist

Why is it dangerous to mix two different full agonists?

They share the same efficacy but have different potencies, which can lead to an overdose

What is the potential effect of mixing a full agonist with a partial agonist?

The partial agonist may prevent the full agonist from binding to receptors, which leads to lower overall efficacy

What is receptor desensitization?

A decrease in response to a drug over time while the drug is bound to the receptor

What is an antagonist?

A drug that binds to a receptor and prevents the binding of an endogenous substance

What is the primary difference between a competitive antagonist and a non-competitive antagonist?

A competitive antagonist competes with endogenous substances for a binding site and lowers potency, whereas a non-competitive antagonist binds to a different site and lowers efficacy

How is TD50 defined in pharmacology?

The dose required to produce 50% of an unwanted response

What does the therapeutic index (TI) indicate?

It is the ratio of TD50 to ED50. A higher TI is preferred because it indicates that the toxic dose and effective dose are far apart

What is pharmacokinetics?

The study of what the body does to the drug

Which four factors (ADME) determine the concentrations of drugs in the body?

Absorption; distribution; metabolism; excretion

How does surface area affect drug absorption via passive diffusion?

Greater surface area allows for increased drug absorption, such as in the small intestine

What are the components of the first-pass effect?

When a drug is taken orally, it is absorbed via the intestines and enters the liver, which metabolizes some of the drug before it reaches the bloodstream

Define bioavailability.

The blood level of an oral drug dose relative to an intravenous drug dose

What is the primary function of Phase I metabolism?

Redox or hydroxylation reactions, mainly performed by cytochrome P450 in the liver, to modify functional groups and make the drug less lipid-soluble

What is the primary function of Phase II metabolism?

Conjugation reactions that attach new functional groups to the drug to make it less lipid-soluble for excretion

What is the result of enzyme induction by a drug on another drug?

The enzyme level increases, leading to more metabolism and lower blood levels of the second drug

How does first-order elimination kinetics differ from zero-order?

First-order

What primary factors affect drug excretion?

Kidney

What is the difference between oral and parenteral drug administration regarding the first-pass effect?

Oral administration is subject to the first-pass effect, whereas parenteral (e.g., IV) administration avoids it and provides 100% bioavailability

What are the components of an amino acid structure?

Central atom; amino group; carboxyl group; R-group

What defines the primary, secondary, tertiary, and quaternary levels of protein structure?

Primary

What are the three steps of transcription?

Initiation

What are the three steps of translation?

Initiation

What are protein chaperones?

Proteins that assist in the folding or unfolding of other proteins

What are the two primary protein localization pathways?

Cytosolic pathway

What is the function of glycosylation in proteins?

It adds a sugar group to form glycoproteins

What is the purpose of protein acetylation?

It adds an acetyl group to protect the protein from degradation

What is the function of phosphorylation in proteins?

It adds a phosphate group to activate or inactivate the protein

What are isoenzymes?

Enzymes that catalyze the same reaction but differ in their chemical and physical properties

What characterizes inorganic cofactors (prosthetic groups)?

They are metal ions that bind to the enzyme active site and stay there after catalysis

What characterizes organic cofactors (coenzymes)?

They are vitamins or vitamin-derived molecules that bind to the enzyme active site, participate in catalysis, and are released afterward

What is feedback inhibition?

A process where the products of a downstream reaction inhibit an enzyme in an upstream reaction

What is allosteric regulation?

A regulatory process where a substance binds to a site other than the active site on an enzyme

What occurs during competitive inhibition?

An inhibitor binds to the active site of an enzyme, which affects substrate binding

What is the structural composition of collagen?

It is composed of alpha helices containing glycine, proline, and hydroxyproline