BIOL 235 - EXAM 1 | ACCURATE QUESTIONS AND DETAILED ANSWERS | GUARANTEED PASS | GRADED A, Exams of Biology

Download BIOL 235 - EXAM 1 | ACCURATE QUESTIONS AND DETAILED ANSWERS | GUARANTEED PASS | GRADED A and more Exams Biology in PDF only on Docsity! BIOL 235 - EXAM 1 | ACCURATE QUESTIONS AND DETAILED ANSWERS | GUARANTEED PASS | GRADED A | LATEST UPDATE 2024-2025 WITH 250+ QUESTIONS A slice of whole grain bread contains 1 gram of fat, 18 grams of carbohydrates, and 4 grams of protein. How many kilocalories does it contain? - Ans - 97 kilocalories nutrition is ___________. – Ans - The study of nutrients and other components of foods and their effect on body function and health which of the following produces toxins that may have cause foodborne illness? - Ans - bacteria Which of the following pathogens is the most common cause of foodborne infection in the United States? - Ans - norovirus At what temperature known as the danger zone, do bacteria readily thrive and multiply? - Ans - between 40 degrees and 140 degrees F Why is ground meat more susceptible to microbial contamination than unground meat? - Ans - it has more surface area The effects of foodborne illness may be most severe and of special concern for: - Ans - -a chemotherapy patient -an 85-year-old grandfather -a 2-year-old child and her mother, who is 5 months pregnant If an outbreak of foodborne intoxication is caused by the consumption of roast beef that was cooked and sliced yesterday and then reheated today by boiling, which one of the four steps to food safety was most probably not followed? - Ans - chill Custards and cream fillings should be eaten soon after preparation and properly refrigerated when stored because: - Ans - bacteria such as staphylococci multiply rapidly If several people become ill from food poisoning while at a picnic, which of the following foods would most likely be the cause? - Ans - tuna salad What is the meaning of the phrase "illness transmission by the oral-fecal route?" - Ans - transmitted from unwashed hands, to food, to mouth Which of the following foods is best known to carry hepatitis A virus? - Ans - raw oysters _________ is defined as breaking apart food by mechanical and enzymatic means in the stomach and small intestines – Ans - digestion the starches and sugar found in grains, vegetables, legumes, and fruits are - Ans – carbohydrates Abby picks up a salad at the campus food court after class everyday before dashing off to her part-time job. Which of the following most likely drives Abby's food choices? - Ans - her busy schedule What aspect of food choices is particularly important for healthcare professionals who help others plan healthy diets? - Ans - cultural competence which dietary standard is set at a level that meets the needs of practically all healthy people? - Ans - RDA which factors affects nutrient levels in food? - Ans - -ripeness when harvested -plant variety -food processing A measure of the nutrient a food provides relative to the energy it provides is known as _______. - Ans - nutrient density A food label ingredient list reads in the following order: wheat flour, soybean oil, sugar, oat fiber, sea salt. What item would be found in the smallest amount in this food? - Ans - sea salt Which is the title given to a person who has a minimum of a bachelor's degree from an accredited university, has completed a supervised internship, and has passed a national examination administered by the Academy of Nutrition and Dietetics? - Ans - registered dietitian Which of the following roles do nutrients preform in the body? - Ans - -nutrients provide energy -nutrients facilitate metabolism -nutrients provide structure for bones, muscles, and other tissues What are the four major types of cells? - Ans - Neurons (nervous), muscle, epithelial, and connective tissue cells What are the main functions of a neuron? - Ans - > Rapidly transmits electrical signals > Highly branched to send or receive > Enables communication between the brain and other organs > Processes simple and complex information What is the main function of muscle cells? - Ans - > Contract and generate force What are the three types of muscle cells? - Ans - > Skeletal > Cardiac > Smooth Which type(s) of muscle cells are involuntarily used? - Ans - Cardiac & Smooth Which type(s) of muscle cells are voluntarily used? - Ans - Skeletal Why are neurons and muscle cells often compared? - Ans - Because they are both excitable Where are epithelial cells located? - Ans - At the surfaces that cover the body or individual organs. Why are epithelial cells so unique? - Ans - Because of their organization and morphology What is the difference between a simple epithelial cell and a stratified epithelial cell? - Ans - a single cell layer thick What is a cuboid epithelial cell? - Ans - Epithelial cell shaped as a cube What is a columnar epithelial cell? - Ans - Epithelial cell shaped as a column What is a squamous epithelial cell? - Ans - Epithelial cell with a flattened shape What is a ciliated epithelial cell? - Ans - Epithelial cell containing cilia Where does the epithelial tissue rest? - Ans - On an extracellular protein layer called the basement membrane. What are the major organs in the lymphatic system? - Ans - lymph vessels and lymph nodes What is the primary function of the lymphatic system? - Ans - Collect extracellular fluid for return to circulation; participate in immune defenses. What are the main organs in the musculoskeletal system? - Ans - Cartilage, bone, ligaments, tendons, joints, and skeletal muscle. What is the primary function of the musculoskeletal system? - Ans - Support, protect, and movement of the body; production of blood cells. What are the main organs found in the nervous system? - Ans - Brain, spinal cord, peripheral nerves and ganglia, sense organs What is the primary function of the nervous system? - Ans - Regulation and coordination of many activities in the body; detection of and response to changes in the internal and external environments; states of consciousness; learning; memory; emotion. What are the main organs in the respiratory system? - Ans - Nose, pharynx, larynx, trachea, bronchi, and lungs. What is the primary function of the respiratory system? - Ans - Exchange of carbon dioxide and oxygen; regulation of hydrogen ion concentration in the body fluid. What are the main organs in the urinary system? - Ans - Kidneys, ureters, bladder, and urethra. What is the primary function of the urinary system? - Ans - Regulation of plasma composition through controlled excretion of salts, water, and organic wastes. Which of the following descriptions INCORRECTLY describes the tissue type? A) Muscle tissue is specialized for contraction and generation of force. B) Epithelial tissue forms glands. C) Nervous tissue is specialized for transmission of electrical impulses. D) Connective tissue is specialized for exchange between the internal and external environments. E) Epithelial tissue lines the lumen of internal organs. - Ans - D) Connective tissue is specialized for exchange between the internal and external environments. What surrounds the cells? - Ans - Extracellular fluid and extracellular matrix (ECM) What is extracellular matrix (ECM) composed of? - Ans - A mixture of proteins, polysaccharides, and in some cases minerals. What is unique of the internal environment in epithelial tissue? - Ans - A layer of epithelial tissue separates the internal environment from the external environment and a plasma membrane separates the intracellular fluid from the interstitial fluid. Is your last meal located in an interior or exterior environment? - Ans - Exterior because it is not inside the cell. The function of most of the body's cells depend on what? - Ans - Different concentrations of solutes in the intracellular and interstitial (extracellular) fluids. What does the movement of the intracellular and interstitial fluids tell us? - Ans - They define the underlying chemistry and physics of physiology. What is the extracellular concentration of sodium? - Ans - 145 mM What is the intracellular concentration of sodium? - Ans - 15 mM What is the extracellular concentration of potassium? - Ans - 5 mM What is the intracellular concentration of potassium? - Ans - 150 mM What is the extracellular concentration of calcium? - Ans - 1 mM What is the intracellular concentration of calcium? - Ans - 0.0001 mM What is the extracellular concentration of chloride? - Ans - 100 mM What is the intracellular concentration of chloride? - Ans - 7 mM Is magnesium most plentiful extracellularly or intracellularly? - Ans - extracellularly Is bicarbonate (HCO3) most plentiful extracellularly or intracellularly? - Ans - extracellularly Is phosphate most plentiful extracellularly or intracellularly? - Ans - intracellularly Are amino acids most plentiful extracellularly or intracellularly? - Ans - intracellularly Is glucose most plentiful extracellularly or intracellularly? - Ans - extracellularly What is a receptor? - Ans - It detects the environmental change and produces a signal through the afferent pathway What is afferent pathway? - Ans - They carry signals to the integration center. What is the integrating center? - Ans - Is the control system that receives information from the sensors and initiates response. What happens once the signal is carried to the integration center? - Ans - The signal gets carried through the efferent pathway. What is efferent pathway? - Ans - They carry signals away from the integration center to the effector What is an effector? - Ans - Cell or cell collection whose change in activity constitutes the response in a control system. Once the signal is sent to the effector the command is made to illicit a response. What is a reflex? - Ans - A specific, involuntary, un premeditated, unlearned "built-in" response to a particular stimulus. Two specialized cells, muscles and glands can also fill in roles of? - Ans - Non-nerve reflexes of effectors, in the case of glands a hormone is secreted into the blood. What is a hormone? - Ans - A type of chemical messenger secreted into the blood by cells of the endocrines system, they can act on many different cells simultaneously because they circulate throughout the body. How many types of chemical messengers are there? - Ans - Three; endocrine, paracrine, and autocrine What is endocrine chemical messengers? - Ans - Signal reaches often distant targets after transport in blood- hormones. What is paracrine chemical messengers? - Ans - Signal reaches neighboring cells via interstitial fluid What is autocrine chemical messengers? - Ans - Signal affects the cell that synthesized the signal Which two important types of cell communication do not require secretion of a chemical messenger. - Ans - gap junctions and juxtacrine signaling What are gap junctions? - Ans - Protein channels linking cytosol of adjacent cells, it allows ions and small molecules to flow between cytosols of the connected cells without having to enter the extracellular fluid. What is juxtracrine signaling? - Ans - A chemical messenger not actually being released from the cell producing it, but is located in the plasma membrane of the cell, when the cell encounters another cell capable of responding to the message the cells link. Why is juxtacrin signaling important? - Ans - Because it allows growth and differentiation of tissues as well as in the functioning of cells that protect the body from pathogens. What does negative feedback do? - Ans - It is a corrective response to change meant to return the body back to homeostasis. The process of maintaining the internal environment in a state compatible for life is called ____________, and it occurs primarily through ________________. A. intrinsic control: homeostasis B. negative feedback: intrinsic control C. homeostasis: negative feedback D. intrinsic control: negative feedback E. positive feedback: intrinsic control - Ans - C. Homeostasis: negative feedback Which of these is not one of the four general categories of cells that make up the body? A. muscle cell B.connective tissue cell C. collagen cells D. epithelial cells E. neuron - Ans - C. collagen cells If a person begins to sweat upon entering a hot room but continued sweating is able to keep the body temperature constant, which of these best describes her condition? A. She is in equilibrium state B. She is using a positive feedback mechanism C. She is not using energy to maintain a constant temperature D. She is in a steady state - Ans - D. She is in a steady state What is the best description of the efferent pathway of a reflex arc? A. Signaling pathway for receptors to influence the integrating center B. The route by which signals from an integrating center reach effector organs C. Signals from the integrating center to receptors D. The route by which receptors send signals to effectors E. The route by which effector organs send signals to receptors - Ans - B. The route by which signals from an integrating center reach effector organs Structure of a neuron - Ans - Which direction is retrograde and which direction is anterograde? - Ans - Retrograde goes towards the soma whereas anterograde moves away from the soma. What glial cell types are found in the central nervous system? - Ans - astrocytes oligodendrocytes microglia ependymal cells What glial cell types are found in the peripheral nervous system? - Ans - schwann cells satellite cells What are the functions of astrocytes? - Ans - guide developing neurons into making the correct connections, modulate synaptic activity, help maintain electrolyte composition of extracellular fluid, and protects cell against toxic substances by forming blood-brain barrier. What is the function of oligodendrocytes? - Ans - They form a layer called myelin sheath around the axons of neurons, they also work to tighten the membrane allowing for rapid transmission of action potentials (electrical signals within the neuron). What is multiple sclerosis? - Ans - An autoimmune system disease in which results in loss of myelination. This happens because the immune system attacks the oligodendrocytes. This in result causes the CNS to slow down or stop communication. What are the symptoms of multiple sclerosis? - Ans - Blurred vision, muscle weakness, and difficulty maintaining balance What is the function of microglia? - Ans - It protects the CNS by phagocytosis by removing foreign material and the remains of dead or injured cells, and protects from oxidative stress. What is the function of ependymal cells? - Ans - It forms epithelia that lines portions of the ventricle system of the brain and the spinal cord, it produces cerebral spinal fluid, and is ciliated allowing the movement of cerebrospinal fluid. What is the function of schwann cells? - Ans - Surround and form myelin sheaths around the lager nerve fibers, this is vital for proper nerve signal conduction. What is the function of satellite cells? - Ans - Surround neuron bodies located in the PNS, this is vital for regeneration. What are synapses? - Ans - Anatomically specialized junctions between two neurons where electrical activity in one neuron influences electrical and chemical activity of another synapse. This is done to pass on information. Can synapses be inhibitory or excitatory to action potentials? - Ans - They can be both depending on the neurotransmitter that is released. What are the functional classes of neurons? - Ans - afferent neurons interneurons efferent neurons What are the functions of afferent neurons? - Ans - they transmit information from the peripheral system to CNS, cell body often in ganglion, What are the functions of interneurons? - Ans - They are the most numerous of the three, are all located in the CNS, process afferent and efferent signals, and key in reflexes. What are the functions of efferent neurons? - Ans - they transmit information from the CNS to the peripheral system, soma in CNS. What is the basis of further subdivision into sympathetic and parasympathetic divisions? - Ans - Anatomical and physiological differences within the autonomic nervous system Where do the sympathetic divisions go when they leave the CNS? - Ans - The sympathetic fibers from the thoracic (chest) and lumbar regions of the spinal cord. Sympathetic division is also called thoracolumbar division. Where do the parasympathetic divisions go when they leave the CNS? - Ans - The parasympathetic fibers from the brain stem and the sacral portion of the spinal cord. Parasympathetic division is also called craniosacral division. Which of the following is not true of glial cells? And why isn't it true? A. They form the myelin for axons B. Neurons outnumber glial cells 10 to 1 in the nervous system C. They deliver fuel molecules to neurons and remove the waste products of metabolism D. They are important for the growth and development of the nervous system E. They regulate the composition of the extracellular fluid in the CNS - Ans - B. Neurons outnumber glial cells 10 to 1 in the nervous system Glial cells are more numerous than neurons and outnumber neurons 10 to 1 in the nervous system, What is the cell membrane composed of? - Ans - phospholipid bilayer, polar (hydrophilic) head groups that face aqueous layers, chains of lipids (hydrophobic) compose the interior. What is the purpose of the cell membrane? - Ans - It forms the barrier between the intracellular solution and the extracellular solution D. There would be no movement of potassium - Ans - B. Potassium would flow out of the cell (outward), potassium would flow from high to low concentration, potassium has a charge that influences its movement What is membrane potential? - Ans - Voltage difference between inside and outside of the cell What charge will the inside of the cell always be? - Ans - negative When does a voltage difference (or membrane potential) exist? - Ans - If there is a separation of charge across the membrane. If the membrane potential is negative what does that indicate? - Ans - The inside of the cell is more negative than the outside, the potential is measured with the inside referenced to the outside Determining resting membrane potential or when the cell is active (action potential) depends on what? - Ans - Two factors: Concentration gradients of ions across membranes and on the ion channels that are present and open in the membrane. Where is sodium concentrated? - Ans - outside the cell Where is potassium concentrated? - Ans - inside the cell When all the charges are balanced what does it mean? - Ans - That there is no membrane potential When there is no membrane potential and potassium channels open, what happens? - Ans - Potassium moves out of the cell because of the concentration gradient What happens as potassium leaves the cell? - Ans - the inside of the cell becomes more negative than the outside (membrane potential develops) What happens when the inside of the cell becomes more negative than the outside? - Ans - it creates an electrical force that opposes the chemical force How is the electrical force affected as more potassium leaves the cell? - Ans - the electrical force increases to pull potassium back into the cell What happens when chemical and electrical forces balance? - Ans - Equilibrium is reached What is the membrane potential when the equilibrium of potassium is reached? - Ans - -94 mV The equilibrium (-94 mV) is for what ion? - Ans - potassium When there is no membrane potential and sodium channels open, what happens? - Ans - sodium moves into the cell What happens as sodium moves into the cell? - Ans - the inside of the cell becomes more positive than the outside (membrane potential develops). What happens when the inside of the cell becomes more positive than the outside of the cell? - Ans - it creates an electrical force that opposes the chemical force What happens to the electrical force as more sodium moves into the cell? - Ans - the electrical force increases to pull sodium back out. What is the membrane potential when the equilibrium of sodium is reached? - Ans - +60 mV The equilibrium (+60 mV) is for what ion? - Ans - sodium What type of channels do neurons have? - Ans - many types of ion channels, specifically potassium and sodium In neurons, where is sodium concentrated? - Ans - outside the cell In neurons, where is potassium concentrated? - Ans - inside the cell When there is no membrane potential and both sodium and potassium channels (more K than Na) are opened, what happens? - Ans - Because of the concentration gradient sodium moves into the cell and potassium move out of the cell. At rest which ion channel has more channels opened (in neurons)? - Ans - There are more potassium channels open than sodium How much more is potassium permeable than sodium? - Ans - 25 times more Which ion influences the membrane potential most? - Ans - potassium Since potassium influences the membrane potential most, what will happen to the membrane potential (become negative or positive)? - Ans - It will become negative What will be the steady state membrane potential in neurons? A. +34 mV B. -154 mV C. -17 mV What happens when the voltage-gated sodium channels open during a nerve impulse? - Ans - Sodium ions will flood into the cell and depolarize, the inside of the cell will have a net positive charge and the outside a net negative charge. What happens when the sodium ions flood into the cell and depolarize? - Ans - It causes neighboring voltage-gated sodium channels to open and moves depolarization along the membrane What is is called when depolarization moves along the membrane - Ans - action potential What changes occur behind the action potential? - Ans - voltage-gated channels close and voltage-gated potassium channels open to restore the resting membrane potential What happens when voltage-gated potassium channels open? - Ans - This allows rapid flow of potassium ions out of the cell and repolarizes the membrane so that the inside is again negative and the outside is positive. Once the membrane is repolarized what happens? - Ans - Sodium-potasssium pumps fully restore membrane potential and reestablish proper concentrations of sodium and potassium ions inside and outside the cell. What happens to the membrane potential if more sodium channels open? A. inward current, depolarization B. outward current, depolarization C. inward curent, hyperpolarization D. outward current, hyperpolarization - Ans - A. inward current, depolarization What happens to the membrane potential if more potassium channels open? A. inward current, depolarization B. outward current, depolarization C. inward current, hyperpolarization D. outward current, hyperpolarization - Ans - D. outward current, hyperpolarization What is a graded potential? - Ans - Changes in the membrane potential that are confined to a relatively small region of the membrane and are linked to active channels Why are they called graded potentials? - Ans - the magnitude of the potential change can vary (graded), big or small response Why are graded potentials given different names? - Ans - depending on location of potential or function they perform What are the different kinds of potentials? - Ans - receptor, synaptic, and pacemaker What is passive current flow? - Ans - electrotonic conduction in the neuron does no spread very far How does an electrical signal spread down the length of a neuron? - Ans - by generating an action potential through voltage-gated channels that open and close based on membrane potential What is an action potential? - Ans - A large change in membrane potential and is an "all or none" response Can you stop or change an action potential? - Ans - no you cannot stop or change the intensity of timing of an action potential What is the ability to produce an action potential called? - Ans - excitability How is excitability possessed by? - Ans - Neurons, muscle cells and some other types of cells How do you cause an action potential? - Ans - a cell must utilize several types of ion channels What initial stimulus serve for an action potential? - Ans - ligand-gated channels and mechanically gated channels Can response get any larger if the stimulus reaches suprathreshold? - Ans - no because all nerves are activated already How long does it take for a complete action potential to occur? - Ans - only in a few milliseconds What is released from the presynaptic terminal? - Ans - acetylcholine What does acetylcholine bind to? - Ans - acetylcholine-gated ion channels (acetylcholine receptors) What happens when acetylcholine-gated channels are opened? - Ans - sodium enters the cell causing depolarization, which is fast because acetylcholine is degraded quickly The size of depolarization depends on what? - Ans - How many channels open and for how long, this is called graded potential Can graded potential summate? - Ans - yes What do ligand-gated sodium channels cause? - Ans - Change in the membrane potential and open voltage-gated ion channels How do action potential propagate in neurons? - Ans - the wave of depolarization usually is in a single direction from dendrite to axonal branches. How do action potential propagate in skeletal muscle? - Ans - They are initiated near the middle of the cells and propagate toward the two ends. Why is it good for skeletal muscle action potentials to start in the middle and propagate toward the two ends? - Ans - It allows for faster contraction of muscles What happens to the inside of the cell membrane during an action potential? - Ans - it becomes positive What does an action potential generate? - Ans - local currents that tend to depolarize the membrane immediately adjacent to the action potential What happens when depolarization is caused by local currents that reach threshold? - Ans - A new action potential is produced adjacent to the original one What happens once the action potential starts? - Ans - it is a continued flow of action potentials to adjacent regions this is electrotonic conduction Does the permeability of sodium change during an action potential? - Ans - no it is the same, this is why the action potential does not become smaller as it is propagated down the neuron (unlike graded potentials) What do refractory period prevent - Ans - the action potential from traveling back towards the soma What happens if there is less resistance to intracellular and extracellular fluid current flow? - Ans - the faster the action potential can propagate Do action potentials progagate faster in smaller or larger fibers? - Ans - in larger fibers (think of small pipe vs. large pipe of flowing water) What does a large fiber offer that a smaller one does not? - Ans - Offers less resistance to local current more ions can flow in given time Does myelination increase or decrease the speed of an action potential propagation? - Ans - increase Why does myelination increase action potential propagation? - Ans - Because it reduces the amount of current "leaking" through the membrane and this improves electrotonic conduction How does the action potential move through myelination? - Ans - it jumps from one gap of myelination to the next What is most metabolically efficient myelinated or umyelinated axons? - Ans - myelinated axons Why ae myelinated axons most metabolically efficient? - Ans - myelin adds speed, reduces metabolic cost, and saves room in the nervous system because the axons can be thinner During an action potential will the ion concentration gradients rundown? - Ans - no because very few ions are required to move across the membrane and Na/K ATPase will maintain ion concentrations Which potential varies in size and depends on initiated event (graded or action)? - Ans - graded Which potential is all-or-none? - Ans - action, once membrane is depolarized to threshold amplitude is independent of the size of initiating event. Which potential can be summed? - Ans - graded potentials Which potential has refractory periods? - Ans - action potential Which potentials degrades with distance (amplitude decreases?) - Ans - graded potential Which potential remains constant in amplitude with distance? - Ans - action potential Which potential relies on initiating conditions for duration? - Ans - graded potentials Which potential remains in constant conditions, given cell type? - Ans - action potentials Which potential can be a depolarization or hyperpolarization? - Ans - graded potentials Which potential is only depolarization? - Ans - action potentials How are graded potentials initiated? - Ans - by environmental stimulus (receptor), by neurotransmitter (synapse), or spontaneously. How are action potentials initiated? - Ans - through graded potentials Which potential relies on ligand-gated channels or chemical or physical changes mechanism? - Ans - graded potential Which potential relies on voltage-gated channels? - Ans - action potentials The fugu fish contains tetrodotoxin, what does it do to voltage-gated sodium channels? - Ans - it blocks them What is electrical synapses mechanism? - Ans - electrical activity in one cell spreads into the next cell Which type of synapse is the most common in neurons ? - Ans - chemical synapses What type of neuronal chemical synapses are there? - Ans - neuron to neuron neuron to effector cell neuron to non-neuron or non-muscle cell What is the chemical synapses mechanism? - Ans - presynaptic releases the neurotransmitter from the axon terminal and the neurotransmitter binds to receptors on postsynaptic neurons and if there's enough neurotransmitter an action potential will start How does a neurotransmitter get released? - Ans - an action potential reaches the terminal and voltage gated calcium channels open, calcium enters axon terminal and the neurotransmitter is released and diffuses into the cleft What happens once the neurotransmitter diffuses into the cleft? - Ans - the neurotransmitter binds to postsynaptic receptors and then neurotransmitters are removed form the synaptic cleft What are the intracellular and extracellular concentrations of calcium? - Ans - intracellular: < 0.001 , extracellular: 1 What is the electrochemical gradient in muscles? - Ans - intracellular: 0.0001 mM and extracellular: 1.0 mM What is the membrane potential of calcium? - Ans - +128 mV Maintaining calcium membrane potential requires? - Ans - energy and very tight control Why is calcium so regulated? - Ans - Because calcium generates electrical signaling, and is an activating ligand (secondary messenger) for some important intracellular proteins. What do the intracellular proteins do? - Ans - control synaptic vesicles with the membrane and control muscles What are the intracellular signaling proteins called - Ans - kinases Consider that the equilibrium of potassium is -94 mV, if the membrane potential is -104 mV what happens if more potassium channels open? - Ans - There will be in inward current and depolarization Where are neurotransmitters produced and stored? - Ans - in vesicles at the axon terminal What happens when the cell is stimulated and intracellular calcium levels increase and stimulate vesicles? - Ans - Vesicles translocate and bind to the plasma membrane via SNARE proteins How are neurotransmitters then released? - Ans - exocytosis How do you terminate the signal in a chemical synapse? - Ans - the neurotransmitter must be removed How do you remove a neurotransmitter? - Ans - diffuse from the cleft, degrade by enzymes, put back into presynaptic cell for reuse, and transport into glial cells What do EPSP (excitatory postsynaptic potential) do? - Ans - serve to bring the membrane potential closer to threshold for generating action potentials What do IPSP (inhibitory postsynaptic potential)do? - Ans - make the cell's membrane potential more negative making it harder to generate an action potential For an action potential to occur: A. the stimulus must reach or exceed threshold B. Sodium influx must exceed potassium efflux C. The membrane must be out of the relative refractory period D. All choices E. A and B - Ans - E. A. the stimulus must reach or exceed threshold and B. Sodium influx must exceed potassium efflux A postsynaptic neuron has three presynaptic inputs - from neurons X, Y and Z. When X and Y are stimulated simultaneously and repeatedly, the postsynaptic neuron reaches threshold and undergoes an action potential. When X and Z are stimulated simultaneously, however, there is no change in the membrane potential of the postsynaptic neuron. What can you tell about presynaptic neurons Y and Z? A. They are probably both excitatory B. They are probably both inhibitory C. Y is probably excitatory and Z is probably inhibitory D. Z is probably excitatory and Y is probably inhibitory - Ans - C. Y is probably excitatory and Z is probably inhibitory What are common postsynaptic receptors? - Ans - ion channels and G protein-coupled receptors or metabotropic receptors What do ion channels or ionotropic receptors do? - Ans - mediated a fast response Where can you find acetylcholine? - Ans - in PNS and CNS Neurons that use acetylcholine as the primary neurotransmitter are known as - Ans - cholinergic neurons Where does degradation of acetylcholine occur? - Ans - in synaptic cleft by acetylcholinesterase What does acetylcholine degrade to? - Ans - acetate and choline What would happen if there was a build up of acetylcholine in the synaptic cleft? - Ans - uncontrolled muscle contraction leading to receptor desensitization and paralysis How would acetylcholine build up? - Ans - through chemical weapons such as sarin How is alzheimer's disease caused? - Ans - loss of cholinergic neurons in central nervous system Besides alzheimer's what happens when there is a loss of cholinergic neurons? - Ans - astrocytes and microglia become overly active and release inflammatory chemicals that further degrade cholinergic neurons What do biogenic amines do? - Ans - Their role in the CNS is consciousness, mood, motivation, blood pressure regulation, and hormonal release Which are the biogenic amine neurotransmitters? - Ans - dopamine norepinephrine epinephrine serotonin histamine Where is serotonin located - Ans - in the brainstem What is the function of serotonin - Ans - regulation of sleep emotions regulates cell growth vascular smooth muscle cell contraction excessive serotonin released by gut causes diarrhea What produces serotonin - Ans - tryptophan Which are the purine neurotransmitters? - Ans - ATP and adenosine Which are the excitatory amino acid neurotransmitters? - Ans - aspartate glutamate Why is aspartate and glutamate excitatory neurotransmitters? - Ans - because they release sodium into membrane Which are the inhibitory amino acid neurotransmitters? - Ans - flycine and GABA Which excitatory amino acid neurotransmitter is the primary? - Ans - glutamate Which receptors does glutamate use? - Ans - both metabotropic and ionotropic Which is the most common receptor glutamate uses? - Ans - ionotropic Which inhibitory amino acid neurotransmitter is the major one used in the brain? - Ans - GABA Which amino acid is GABA modified from - Ans - glutamate What does GABA do? - Ans - They are small interneurons that dampen activity within neural circuits What does GABA ionotropic receptor do? - Ans - It increases chloride influx into the cell resulting in hyperpolarization of the postsynaptic membrane What stimulates GABA synapses - Ans - ethanol What happens when GABA synapses are stimulated - Ans - it inhibits excitatory glutamate synapses and resulting in global depression of electrical activity in brain Which is the major neurotransmitter released from inhibitory interneurons? - Ans - glycine What does glycine do? - Ans - it binds to ionotropic receptors and allows chloride to enter Why is glycine essential - Ans - it maintains a balance of excitatory and inhibitory activity in the spinal cord integrating centers that regulates skeletal muscle contraction What are neuropeptides - Ans - short amino acid chains with peptide bonds Which of the following statements about acetylcholine is correct? A. Acetylcholine binds to cholinergic receptors B. Acetylcholine binds to nicotinic and muscarinic receptors