Physiology Final Exam
Channel-linked, or ionotropic receptors, have G proteins associated with them.
False
Electrical synapases are only excitatory.
False
Electrical synapses allow neurotransmitters to pass through them.
False
Endergonic reactions will always proceed spontaneously in the forward direction
False
Oxygen and carbon dioxide diffuse through the plasma membrane through specialized pores called oxyporins.
False
The autonomic nervous system includes a sensory division.
False
Under resting conditions, the sodium channel responsible for generating an action potential is closed and incapable of opening.
False
What is the most common inhibitory neurotransmitter in the central nervous system?
GABA
Which of the following correctly describes a pathway for secretion of a hormone under the control of tropic hormones?
GHRH stimulates GH release, which stimulates insulin-like growth factor release.
Which of the following statements about glucose cotransport with sodium is TRUE?
Glucose and sodium both move into the cell.
Which of the following are 2nd messengers that are used by G protein coupled receptors?
IP3 (inositol triphosphate) cAMP diacylglycerol (DAG)
Which of the following is an example of negative feedback?
If blood pressure increases above normal, baroreceptors in major arteries detect the change and send signals to the brain. Certain areas of the brain then send signals to the nerves that control the heart and blood vessels to make the heart beat slower and the blood vessels increase in diameter, which in turn reduce the blood pressure
Which statement best describes why atrial depolarization is usually not detected on a normal ECG?
It occurs at the same time as the QRS complex.
Insulin is a hormone that regulates blood glucose levels. It is released when glucose levels increase above normal. Based on the concept of negative feedback, what effect will insulin have on blood glucose levels?
It will decrease them
Which of the following is a property of isotonic skeletal muscle contraction?
Load is less than the force generated by the muscle.
Which three factors are most important in determining and maintaining resting membrane potential?
Na+/K+ ATPase pump ion concentration gradients membrane permeability to ions
Which is NOT true about the P O2 in the lungs?
O2 is very soluble in water or plasma
Which of the following components of an ECG represents atrial depolarization?
P wave
What is the primary driving force for the binding of oxygen to hemoglobin?
PO2
If the soma of a neuron became more permeable to potassium, which statement below best describes the graded potential that would be generated in the soma?
Potassium would leave the cell, causing the membrane to hyperpolarize.
Which of the following is a CORRECT example of short-loop negative feedback?
TSH inhibits the release of TRH.
Blood glucose is a regulated variable controlled by a negative feedback loop. Explain what is meant by the term negative feedback and discuss how this mechanism would work in the case of high blood glucose. Use the terms: regulated variable, set point, sensors, integrators (or integrating center), effectors.
The reason why it is referred to as a negative feedback loop is because the process occurs as response in counteracting a variance from a set point. In the case of high blood glucose, the regulated variable is the blood's glucose level, which has a set point (a standard level) in which it must remain to maintain homeostasis. When blood glucose levels are too high, an error signal occurs. Beta cells act as sensors and signal the pancreas to release insulin into the blood stream, which acts as the integrator (integrating system). Insulin provokes the liver, adipose tissue and skeletal muscle to engage in glycogenesis, which is the process of turning glucose into glycogen to store, and/or they are urged to enhance the use of glucose in cellular function. The effectors in this negative feedback loop are the insulin, liver, adipose tissue and skeletal muscle, for they carry out the actions necessary to return the set point of blood glucose level.
What is the meaning of carrier proteins and pumps becoming saturated?
These transporters have reached a maximal net flux, beyond which further increases in concentration no longer affect their rate.
ATP is required to remove calcium from the cytosol of muscle cells and end a muscle contraction.
True
All cells have a negative resting membrane potential
True
Glycogenolysis is an example of a catabolic reaction
True
The magnitude of response at the target cell depends on both the concentration of hormone and the concentration of receptor.
True
The resting membrane potential is closer to the potassium equilibrium potential.
True
When intra-alveolar pressure is greater than atmospheric pressure, air moves out of the lungs
True
In the peripheral nervous system, ________ neurons carry sensory and visceral information to the central nervous system, and ________ neurons leave the central nervous system and innervate organs, which are usually muscles or glands.
afferent : efferent
As a general rule, the magnitude of a target cell's response to a chemical messenger depends on which three factors?
affinity of the receptor concentration of messenger number of receptors
The figure below shows the relationship between frequency of stimulation and force generated by a muscle fiber. The reason(s) why the tension increases with each stimulus is
all of the options are correct
Why does the amount of tension produced eventually plateau? (the blue dotted line
all troponin has calcium bound to it
Regulation of an enzyme through reversible binding of a modulator to a regulatory site on an enzyme is specifically called
allosteric regulation
The function of a second messenger system is to
amplify the response of the first messenger.
Which of the following is responsible for the repolarization of pacemaker cells?
an increase in PK
Which type of chemical messenger, when released, binds to receptors on the cell that released the chemical messenger?
autocrine
What type of synapse occurs between an axon terminal of one neuron and the axon from another neuron?
axoaxonic
Which of the following is NOT true of an antagonist?
binds to a receptor and causes normal response
Which of the following is NOT a possible effect of calcium in a transduction pathway?
blocks ion channels from opening
What is required in order to release neurotransmitter at the axon terminal?
calcium
Which of the following ions binds to calmodulin to ultimately activate a protein kinase?
calcium
The synaptic delay is caused by the time required for which step of neurotransmitter release?
calcium entry to trigger exocytosis
is released from its binding site on the / pump as a result of the
conformational change decreasing the affinity of the binding site.
The receptors for steroid hormones are most likely to be found in the
cytosol
Hypoventilation would lead to a(n) ________ within the systemic arteries
decrease in PO2 and increase in PCO2
What happens to the inner diameter of the walls of the respiratory tract as it moves down from the upper conducting zone to the lower respiratory zone?
decreases
As the lungs expand, intra-alveolar pressure ________ and air moves ________ the lungs
decreases : into
The opening and closure of the atrioventricular and semilunar valves is driven by
differences in pressure across the valve
Which of the following molecules is LEAST likely to diffuse through the phospholipid bilayer of the plasma membrane?
disaccharide
Molecules tend to move spontaneously _____________ their chemical gradient
down
Which of the following physiological responses is associated with an elevation in parasympathetic nervous system activity?
enhanced absorption of nutrients
Which of the following pairs of hormones are NOT antagonists?
epinephrine and norepinephrine
When a reaction occurs and that reaction is moving equally in a forward and reverse direction, that reaction is said to be at
equilibrium
What is the volume of air present in the lungs when the lungs are at rest (in between breaths)?
functional residual capacity
The influx of calcium into the axon terminal of a chemical synapse is responsible for which of the following?
fusion of vesicles to the membrane and of exocytosis neurotransmitter
Direct communication between cells in contact with one another is accomplished through
gap junctions
The synthesis of glucose from non-carbohydrate precursors is called ________ and it occurs in the ________.
gluconeogenesis : liver
What is the storage form of carbohydrates in animal cells?
glycogen
Which type of skeletal muscle fiber fatigues rapidly?
glycolytic
Which of the following would NOT increase the rate of simple diffusion across the phospholipid bilayer of the plasma membrane?
greater number of protein carriers
What are the effectors in this homeostatic reflex? Eating a salty meal increases blood volume and pressure, stretching blood vessel walls. Nerve signals sent to the brainstem stimulate changes in hormonal and neural signaling. The heart rate is slowed, blood vessel walls are relaxed, and the kidneys increase urinary salt. The blood pressure returns toward normal
heart kidneys blood vessels
Which type of chemical messenger is released into the bloodstream by an endocrine gland where it can affect target cells throughout the body?
hormone
Typical responses to ________ messengers require a long time to develop because they bind to segments of DNA and alter transcription of mRNA and translation of that mRNA into a functional protein.
hydrophobic
What is an increase in alveolar ventilation to match the demands of increased metabolic activity in the cells called?
hyperpnea
What ensures that blood levels of a specific releasing hormone are locally high in order to stimulate the pituitary?
hypothalamic-pituitary portal system
Which of the following best describes the function of the myelin sheath?
increase conduction velocity of the action potential down the axon
Hyperventilation would lead to a(n) ________ within the systemic arteries.
increase in PO2 and decrease in PCO2
What does contraction of the diaphragm cause?
increase in the volume of the thoracic cavity and, therefore, a decrease in intra-alveolar pressure
Which of the following physiological responses is associated with elevated sympathetic nervous system activity?
increased contractile force of the heart
What does contraction of the diaphragm cause?
inspiration
The total body water (TBW) in all the body's fluid compartments consists of:
interstitial fluid (ISF) intracellular fluid (ICF) plasma extracellular fluid (ECF
What phase of the cardiac cycle is the heart in when all four valves of the heart are closed and ventricular pressure is building, but is not yet great enough to open a valve?
isovolumetric contraction
In many metabolic reactions, there is a molecular switch that functions to turn proteins on and off. Protein ________ activate proteins by adding a _______ group to them while protein _________ remove a ______ group.
kinase phosphate phosphatases phosphate
Glucose is stored in the form of glycogen primarily within the ____and the ____
liver and muscle
The compliance of the lungs can be determined by measuring the change in ________ for a given change in ________.
lung volume : transpulmonary pressure
The release of ________ from the pineal gland is important for establishing ________.
melatonin : circadian rhythm
Which of the following term describes the unequal distribution of positive and negative ions across the plasma membrane? In other words, the fact that there is a charge difference (in mV) between the inside and outside of a cell.
membrane potential
Contraction of skeletal muscle fibers is stimulated by what type of neuron? (not a trick!)
motor
What type of receptor is both metabotropic and cholinergic?
muscarinic
What molecule, present primarily within oxidative skeletal muscle cells, acts as an oxygen buffer due to its ability to bind oxygen?
myoglobin
What is the mostcommon mechanism for maintaining homeostasis?
negative feedback
At metabotropic receptors, a(n)
neurotransmitter binding to a receptor stimulates a G-protein, which then activates a second messenger through one or more enzymatic actions.
Which type of acetylcholine receptor is responsible for the rapid opening of ion channels in response to the interaction between the ligand and receptor?
nicotinic
In active transport, the affinity of the carrier protein for the molecule being transported is greater on which side of the membrane? (Think what happens with Na+ and K+ binding in the ATPase pump!)
on the side where the molecule is in lower concentration
G proteins, once activated by their receptors, can do which of the following?
open or close an ion channel activate phospholipase C activate adenylyl cyclase
Which type of skeletal muscle fiber contains a high concentration of mitochondria?
oxidative
White blood cells are an important component of our immune system. One thing they do is consume and destroy bacteria by extending their plasma membrane around the bacterium and bringing it inside the cell in a vesicle. By what process do they engulf the bacterium?
phagocytosis
When a tyrosine kinase receptor is activated by a ligand such as a growth factor the receptor
phosphorylates a protein and activate a signaling cascade
Which of the following is found has higher concentration inside the cell than outside?
potassium
Which of the following is found in greater concentration inside the cell than outside?
potassium
Closure of the atrioventricular valve occurs when
pressure inside the ventricle is greater than pressure inside the atrium
Which of the following would increase the likelihood of an action potential being generated in a postsynaptic cell?
presynaptic excitation at an excitatory synapse
Match each tropic hormone with its target structure/organ
prolactin-breasts thyroid stimulating hormone - thyroid gland adrenocorticotropic hormone - adrenal gland growth hormone - cells of the body/liver leutinizing hormone - gonads
What is the function of ciliated cells in the conducting zone?
push mucus containing trapped particles upward toward the glottis
The arrow is pointing to the _____________ phase of a typical twitch. During this phase, calcium _________ is occuring
relaxation; reuptake
What is the function of the sodium-calcium exchanger in cardiac muscle?
remove calcium from the cytosol by transporting it to the extracellular fluid thereby relaxing the muscle
What is the thin barrier (0.2 μm) that allows for the efficient exchange of gases between the lungs and the blood called?
respiratory membrane
The functional (contractile) unit of muscle is called a ___________. (one word)
sarcomere
A secondary endocrine organ is one that
secretes hormones, but is better known for another function.
In the absence of an active chloride transporter in the plasma membrane, chloride acts to ________ membrane potential by resisting any change in membrane potential.
stabilize
What chemical targets CB1 receptors?
tetrahydrocannabinol
During isovolumetric relaxation
the AV and semilunar valves are closed and ventricular pressure is decreasing.
What does this graph tell you about how a substance diffuses through the membrane?
the greater the difference in concentration across the membrane results in greater movement across the membrane
What does this graph show about the relationship between how many receptors would be bound to a messenger?
the high-affinity receptors reach saturation at a lower messenger concentration than do the low-affinity receptors
In crossbridge cycling, converts the myosin head into the high-energy state?
the hydrolysis of ATP
The direction of change in membrane potential, in response to a stimulus that initiates a graded potential, is dependent upon
the ion channels that are opened or closed
Under resting conditions, heart rate is primarily under the control of what control system?
the parasympathetic nervous system
What determines the strength of a graded potential?
the size of the stimulus
Which situation describes a feedforward mechanism?
the smell of yummy food triggers salivation and feelings of hunger
As skeletal muscle is stretched beyond the length where optimum force is developed,
the thin filaments are pulled away from the thick filaments, thereby reducing actin's ability to interact with myosin.
Where do the preganglionic neurons of the sympathetic nervous system emerge from the spinal cord?
thoracic and lumbar regions
Which of the following is a measure of the distending (stretching outward) force across the lungs?
transpulmonary pressure
A muscle is stimulated at a frequency that allows the muscle to relax completely between contractions. However, the amount of tension increases with each contraction. What is this called?
treppe
Secretion of hormones from the anterior pituitary is stimulated by ________ released from the ________.
tropic hormones; hypothalamus
During increased exercise, the oxygen dissociation curve shifts to the right in response to increased temperature. This causes more ________ and less ________ of oxygen in the tissues where it needs to be delivered.
unloading; loading
Blood is ejected from the left ventricle once pressure within the
ventricle is greater than pressure within the aorta.
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Which of the following tropic factors (hormones) are released into the hypothalamic - pituitary portal vein?
-GHIH -GnRH -PRH -CRH -dopamine (PIH)
In excitation-contraction coupling, calcium plays an important role in contraction. If no calcium is present, what happens?
-No crossbridges form between actin and myosin -troponin holds tropomyosin over myosin binding sites on actin -Muscle is relaxed
The sodium-proton exchanger is an example of a(n)
-antiporter -secondary active transporter
Which of the following will cause a shift in the hemoglobin-oxygen dissociation curve to the right?
-decrease in pH -increase in temperature -increase in 2,3-BPG (2,3-bisphosphoglycerate)
Which of the following is a mechanism whereby neurotransmitters are rapidly removed from the synaptic cleft? (select ALL that apply)
-degradation by enzymes -reuptake across the presynaptic membrane -diffusion out of the cleft
Match each label (A, B, and C) on the graph of pacemaker potentials with the correct ion channel description. Note: you will not use all the options!
-funny channels open, Na+ moves in, K+ moves out -T type calcium channels open, calcium moves in -L type calcium channels open, calcium moves in.
Cardiac output is determined by what two variables?
-heart rate -stroke volume
An increase in vagus nerve activity results in a decreased heart rate as a result of
-increase open state of K+ channels -activating muscarinic ACh receptors -increased closed state of Ca2+ channels -decreased rate of pacemaker depolarization
Which of the following will increase the unloading of oxygen within the tissue?
-increased body temperature -increased hydrogen ion concentration
Which of the following transport mechanisms is passive?
-movement of potassium through ion channels -movement of water through aquaporins -movement of sodium through ion channels
The SA node is innervated by the
-parasympathetic nervous system -sympathetic nervous system
The binding of a neurotransmitter to its receptor at an inhibitory synapse can lead to the opening of ________channels.
-potassium -chloride
Which of the following transport mechanisms requires energy?
-primary active transport -secondary active transport
What does a selectively permeable membrane do?
-separates the ECF from the ICF -allows for waste products to travel outside the cell -allows for nutrients to travel into the cell -allows some molecules through but not others
Which muscles are innervated by autonomic nervous system?
-smooth muscle -cardiac muscle
Preganglionic and postganglionic sympathetic neurons are anatomically arranged in what three patterns?
-sympathetic (two neuron) chains -direct innervation of the adrenal medulla -collateral ganglia
Place the events of inspiration in order.
1) Neural stimulation of inspiratory muscles 2)diaphragm contraction and external intercostals contract increasing lung volume. 3)outward pull on pleura 4)alveoli expand; decreasing alveolar pressure 5)air flows into alveoli by bulk flow
Explain the steps of the Na+/K+ ATPase pump. Use terms such as affinity, conformational change, phosphorylated, and dephosphorylated
1) The carrier protein that is integrated within the plasma membrane has an affinity for the higher concentration of Na+ molecules in the extracellular fluid, so it faces that direction. It is also shaped in a way that easily allows 3 Na+ molecules to settle within the protein. 2) ATP then reaches the active site on the protein and becomes dephosphorylated, releasing energy in that process. 3)The carrier protein then acts as a pump, allowing Na+ to enter the cell, while also going through a conformational change. 4) The protein has now changed in shape, and faces the ICF, allowing 2 K+ molecules to settle within the protein, ready to be pumped out of the cell in the exchange. 5) ATP again binds to the active site on the protein, becomes dephosphorylated and the release of energy pumps the 2 K+ out of the cell. The charge of the cell in this process becomes more negative due to the difference of 3 Na+ and 2 K+ being exchanged.
Place the events of the conduction system of the heart in the correct order.
1)AP initiated in SA node 2)signals spread through atrial muscle via interatrial pathways 3)Action potentials spread through the atria to the AV node, where conduction slows. 4)signal travels through the bundle of his 5)splits into right and left bundle branch 6)Action potentials spread upward through the purkinje fibers into ventricular muscle
List the 8 steps that occur during synaptic transmission in a chemical synapse. Note the last three have to do with removal of the neurotransmitter from the synaptic cleft
1)Action Potential arrives,2) Voltage gated Ca+2 channels open (depolarized). 3) The entry of calcium triggers vesicle docking and secretion. 4)Neurotransmitter diffuses across membrane and binds to receptors in synaptic cleft. 5)Cellular Response is terminated be leaving the synaptic cleft. 6) The Neurotransmitter is broken down by enzymes. 7)Neurotransmitter reuptake in the presynaptic neuron can occur 8) NT can diffuse out of the synaptic cleft.
List the six steps of excitation-contraction coupling in skeletal muscle. (make a list, be concise!)
1)Action potential spreads across sarcolemma and T tubles 2) Calcium is released into SR 3)Calcium binds to actin, tropomyosin is moved to unblock myosin heads, myosin heads attach to actin, 4) Crossbridge cycle begins, contraction occurs 5)Calcium is removed, and the binding sites on actin are blocked again by the tropomyosin 6) Muscle relaxes
Place the components of the reflex arc in order beginning with the stimulus.
1st-stimulus 2nd- receptor 3rd -integrating center 4th- effector 5th -response
Describe the events associated with generation of an action potential. You should include the changes in membrane permeability during depolarization, repolarization, and hyperpolarization. You do not need to describe the membrane potential at rest.
A stimulus occurs, and sodium channels open in depolarization. The stimulus must reach threshold (all or none), which is a mV of -55 in order to go from a graded potential to an action potential. This will bring the mV from -70 (resting mV) to +30 to+40 at peak depolarization, in which a ton of Na+ channels are open. Once peak depolarization is met, repolarization occurs when Potassium channels open and K+ exits the membrane. This happens so "well" that hyperpolarization occurs, and so the Na+/K+ pump will bring it back to resting mV.
What is the correct order for the steps of synaptic transmission at the motor end plate?
An action potential arrives at the axon terminal.-1st Voltage-dependent calcium channels on the plasma membrane open - 2nd Acetylcholine is released by exocytosis. - 3rd Acetylcholine binds to postsynaptic receptors - 4th Channels that primarily allow diffusion of sodium are opened. - 5th An action potential is produced on the muscle cell membrane - 6th
Which is NOT true about the Carbonic Acid equation?
An increase in CO2 causes a decrease in H+
Which posterior pituitary hormone regulates water balance?
ADH
Which of the following describes the effect of end-diastolic volume on stroke volume?
An increase in end-diastolic volume stretches ventricular muscle cells to lengths closer to optimum, increasing the strength of contraction and thereby increasing stroke volume.
Which statement best describes explains the loading and unloading of oxygen in hemoglobin? (Hint: law of mass action)
As oxygen levels in the pulmonary capillaries increase, more oxyhemoglobin is formed. Conversely, as oxygen levels in the systemic capillaries decrease, the reaction reverses and releases oxygen from hemoglobin.
At rest, what is the relative contribution of the sympathetic and parasympathetic nervous systems to the regulation of homeostasis?
Both systems are active but the parasympathetic predominates
During isometric contraction. the muscle fiber shortens.
During isometric contraction. the muscle fiber shortens.
Which item is not part of the external environment?
ECF
Body temperature and plasma concentrations of ions such as potassium, sodium, and calcium change within a physiological range yet we have mechanisms to maintain them at relatively stable values. These things that we maintain in our bodies are called
Regulated Variable
Oxygen diffuses from blood into cells down its concentration gradient. As cells become more active and oxidative phosphorylation increases in the cell, which of the following occurs?
The concentration gradient for oxygen increases and oxygen movement into the cell increases.
Which of the following best describes the electrochemical forces acting on sodium and potassium ions at the resting membrane potential?
The force on sodium ions is to move into the cell, and the force on potassium ions is to move out of the cell.
Which of the following is an effect of parasympathetic activity to the heart?
The rate of spontaneous depolarization in SA nodal cells decreases
During presynaptic inhibition, the release of a neurotransmitter from the modulating neuron causes which of the following?
a decrease in calcium entry into the axon terminal of the neuron it is modulating
Equilibration of pressure between the intrapleural space and the alveoli will lead to which of the following?
a pneumothorax (the lung will collapse)
With respect to their innervation, individual skeletal muscle fibers (cells) are innervated by
a single motor neuron.
Once released, acetylcholine is degraded by extracellular enzymes into what product(s)?
acetate + choline
The concentration of an anion inside a cell is 0.3%. The concentration of this anion outside the cell is 0.1%. How could the cell obtain more of this ion inside the cell?
active transport
An example of a slow excitatory postsynaptic potential that involves closure of potassium channels relies on cAMP produced by what enzyme?
adenylate cyclase
Which of the following hormones is NOT released from the adrenal gland?
adrenocorticotropic hormone
