BIO 140N Exam 1
Secretion of hormones for body regulation.
Endocrine System
Provides protection and support; lines organs
Epithelial
What is hyperpolarization?
Hyperpolarization refers to a state where the potential across the membrane is more negative than the resting potential
Conducts electrical impulses within the body and between the body and the outside environment
Nervous
Control system for the body that quickly responds to both internal and external changes.
Nervous System
What happens if twice as many inhibitory postsynaptic potentials (IPSPs) as excitatory postsynaptic potentials (EPSPs) arrive in close proximity at a postsynaptic neuron?
No action potential results
When the voltage-gated potassium channels open, what happens to the potassium ions?
Potassium Ions rush out of the cell
The ions that maintain the ionic imbalance in a resting neuron are
Potassium and Sodium
What is the main function for carbohydrates?
Provides energy as a primary fuel for cells
The "receiving region" of the neuron that normally receives a stimulus (from a sensory receptor or another neuron) and carries it towards the cell body/soma is called
The dendrite
During depolarization
The inside of the cell becomes less negative due to an influx of sodium ions
The autonomic nervous system may cause activation or inhibition, depending on the division that is active and the target that is affected.
True
Removes metabolic wastes from the blood; regulates electrolytes, water and the acid-base levels in the body.
Urinary System
Which statements concerning osmosis are correct? Choose all that apply.
Water moves across a selectively permeable membrane through aquaporins A solution with the same solute concentration as that inside body cells is isotonic A hypertonic solution has a higher solute concentration than the solute concentration inside body cells
Neurotransmitters categorized as inhibitory are expected to ________
hyperpolarize the membrane
During an inhibitory postsynaptic potential (IPSP)
postsynaptic membrane hyperpolarizes
We can touch our finger to our nose while our eyes are closed in part because we can sense the position and movement of our joints as well as the length of stretch in our muscles. These sensations create awareness of our body's positioning. Which of the following receptors are most likely responsible for this ability?
proprioceptors
What is repolarization?
the membrane returns to its resting membrane potential
By mistake, sterile distilled water is used as an intravenous (IV) solution. The Na+ concentration in the water is 0% and the Na+ concentration inside the red blood cell is 0.9%. Is this a serious problem? What will happen and why?
this would be in a hypotonic state because the Na+ is not the same percentage as it is in the water. This would be a major problem because you would start destroying your cells since they aren't equal. To equilibrate the system, water will move into the red blood cells and they will burst.
Which physiological responses results from sympathetic action?
increase in heart rate constriction of arterioles stimulation of glycogenolysis
Describe the movement of water in osmosis.
moves from a higher concentration to a lower concentration across a selectively permeable membrane; does not involve a specific carrier protein; a passive process.
In the human body, which is an example of endocytosis?
Phagocytosis of foreign particles by a white blood cell
Drains excess fluid from extracellular spaces; contains white blood cells involved in cell protection and immunity.
Lymphatic System/Immunity
What is the smallest contractile (functional) unit of a skeletal muscle fiber? (2 points)
A sarcomere
In skeletal muscle contraction, during the power (working) stroke (2 points)
ADP and Pi are released from myosin
During skeletal muscle contraction, which neurotransmitter is released at the neuromuscular junction?
Acetylcholine
What happens to acetylcholine AFTER it stimulates the membrane potential? (2 points)
Acetylcholinesterase destroys the acetylcholine
In the human body, which can be moved by active transport?
Amino acids and Sodium (Na+) and Potassium (K+) ions
The part of the nervous system that is responsible for the regulation of smooth muscles, glands, and cardiac muscle is the
Autonomic nervous system
While you are working on this assignment, your heart is beating normally and your most recent meal is digesting. Which nervous system is acting?
Autonomic nervous system
During skeletal muscle contraction, what is the function of calcium ions?
Bind to troponin to expose actin active sites
In skeletal muscles, tropomyosin (2 points)
Blocks the myosin binding sites on actin and inhibits muscle contraction
In the sarcoplasm of the skeletal muscle, how is oxygen is stored?
By myoglobin
Which of the following attributes are associated with the myelin sheath? Choose all that apply.
Can electrically insulate nerve fibers Is produced by glial/Schwann cells Can increase the speed of transmission of nerve impulses Is associated only with axons
In the human body, which is an example of simple diffusion?
Carbon dioxide (CO2) moves from a higher concentration in the cells to a lower concentration in the lungs
Transportation system for blood carrying gases, nutrients, and wastes.
Cardiovascular System
The part of the nervous system that acts as the command center to analyze sensory input and determine motor responses is the
Central nervous system
Anesthetics act to lessen pain by inhibiting nerve transmission. Which of the three substances listed might be the most effective anesthetic?
Chemical C blocks the neurotransmitter receptors on the postsynaptic neuron
Provides insulation and transport of substances; holds together and supports body structures
Connective
An action potential occurs in the motor neuron; Calcium ions are released and cause the synaptic vesicles to release acetylcholine (ACh) by exocytosis; Acetylcholine diffuses across the synaptic cleft and binds to ACh receptors on the sarcolemma; Membrane ion permeabilities change and an action potential occurs in the muscle membrane; Depolarization occurs; Acetylcholinesterase breaks down acetylcholine.
Consider what happens when the motor neuron stimulates the muscle cell. What is the correct order of events at the neuromuscular junction? (5 points) Acetylcholine (ACh) binds to ACh receptors on the sarcolemma; Acetylcholine diffuses across the synaptic cleft; An action potential occurs in the motor neuron; Synaptic vesicles release acetylcholine by exocytosis and calcium ions are released; Acetylcholine breaks down acetylcholinesterase An action potential occurs in the motor neuron; Calcium ions are released and cause the synaptic vesicles to release acetylcholine (ACh) by exocytosis; Acetylcholine diffuses across the synaptic cleft and binds to ACh receptors on the sarcolemma; Membrane ion permeabilities change and an action potential occurs in the muscle membrane; Depolarization occurs; Acetylcholinesterase breaks down acetylcholine. Acetylcholine (ACh) binds to receptors on the sarcolemma; Membrane ion permeabilities change; An action potential is generated in the motor neuron; Calcium ions are released and cause synaptic vesicles to release acetylcholine by endocytosis; Acetylcholine diffuses across the synaptic cleft; Acetylcholinesterase breaks down acetylcholine.
Which of the following are functions of muscle tissue?
Contractility, Extensibility, Extensibility
What is depolarization? Explain what happens during depolarization to generate the action potential. Which ions are involved and which channels?
Depolarization is when a neuron is decreasing in polarity which is caused by sodium ions rushing inside of the neuron. What is depolarization of a neuron? - Studybuff Links to an external site. After the sodium ions rush in, it will cause the neuron to go into a hyperpolarization period which then activates the action potential. Khan Academy Links to an external site. The sodium ions are involved with the sodium channels and the potassium ions are involved with the potassium channels. What is depolarization of a neuron? - Studybuff
Breaks down nutrients for absorption by the body; eliminates indigestible substances as feces.
Digestion System
Briefly describe the process of blood clotting. What type of feedback mechanism is involved? Explain your response.
During blood clotting, a blood vessel will shrink. The reason they shrink is that there is a chemical reaction that tells the body that it can't allow any more blood out of a specific area. There are platelets in your blood that will go to the spot where you're losing blood, and they will "patch" the spot. There is a positive feedback mechanism used when it comes to blood clotting. A positive feedback mechanism will do the exact opposite of a negative feedback mechanism meaning that a positive mechanism will increase the body's response to the stimuli instead of reversing it.
Which statements concerning exocytosis are correct? Choose all that apply.
During exocytosis, ATP energy is required. During exocytosis, substances such as neurotransmitters are released from a cell. During exocytosis, substances move out of a cell
Explain the molecular reason why a second action potential cannot occur until the first is completed.
During the first action potential, the neuron is basically reading what it needs to stay at its original resting potential. A second potential wouldn't be able to do anything because there has to be a first potential to see what exactly the neuron needs in order to stay "healthy".
The term rigor mortis describes the stiffness of the body. It appears appears in face about two hours after death and completes setting in about 6 to 8 hours after death. The muscle physiology involved which causes this to occur is https://www.ncbi.nlm.nih.gov/books/NBK549867/#:~:text=Rigor%20mortis%20is%20the%20post,filaments%20in%20the%20muscle%20fibers (Links to an external site.).
EXTRA CREDIT: While hiking one afternoon in June, a young woman found a dead body. She called the police. After the police arrived she watched the initial examination. The body was stiff. But it wasn't frozen as the air temperature was 75°F. (4 extra credit points) What term describes the "stiffness" of the dead body? Discuss the muscle physiology involved which causes this to occur, including the role of ATP. When had the death occurred: hours ago (12 - 48 hours) or several days ago (more than 3 days)? How do you know? Be sure to use your own words. Do not use abbreviations. Include a citation for the reference (text or other sources) you used in formulating your response. If you do not include a citation, you will lose 2 points for this question.
Why is the receptor the important element determining the effect a neurotransmitter has on a target cell?
Each neurotransmitter has different receptors, and the receptors are responsible for opening up the ion channels. Also, a neurotransmitter will only lock onto a receptor that it needs to so that the nerve receptor sends the correct signal.
Consider the action of a calcium channel blocker. Calcium channels blockers are used to treat high blood pressure. How do they work? During the transfer of information across a chemical synapse (involving a presynaptic neuron and a postsynaptic neuron), what step would be disrupted ("blocked") by a calcium channel blocker?
Exocytosis of the neurotransmitter from the presynaptic neuron
GOT WRONG
Fast glycolytic muscle fibers are best suited for: (2 points) Swimming the 200-meter freestyle Hitting a home run Competing in a 5k walk-run Cross country skiing
are best suited for short distance (100 meter) running
Fast oxidative muscle fibers: (2 points) are best suited for short distance (100 meter) running are best suited for moving a grand piano are best suited for running a marathon
Which of the following are functions of proteins? Choose all that apply.
Form the contractile filaments involved in muscle contraction Significant catalytic agents in biological pathways Make up the supportive framework of the body Function in immunity
How could you increase the magnitude of excitatory postsynaptic potentials (EPSPs) generated at a synapse?
Increase Na+ permeability.
Consider the action of certain anti-depressive drugs. These drugs maintain an increased concentration of neurotransmitters such as serotonin within the synapse. How might these drugs cause this effect?
Inhibit reuptake of the neurotransmitter
External body covering; provides protection; contains sensory receptors, glands.
Integumentary System
Which of the following are functions of lipids? Choose all that apply.
Make up the main structural component of cell membranes. Provide insulation in the body. Used to synthesize steroids, some vitamins, and bile salts Present as prostaglandins and other eicosanoids
Perpetuation of the human species.
Male and Female reproductive systems
During an excitatory postsynaptic potential (EPSP)
More sodium ions flow into the neuron than potassium ions flow out of the neuron
Neurons that transmit impulses only away from the central nervous system are
Motor (efferent) neurons
Describe the movement of molecules in facilitated diffusion.
Move from a higher concentration to a lower concentration, involves a specific carrier protein and is a passive process
Describe the movement of molecules in diffusion
Move from a higher concentration to a lower concentration; does not involve a specific carrier protein; a passive process.
Describe the movement of molecules in active transport.
Move from a lower concentration to a higher concentration; involves a specific carrier protein; requires ATP energy input
Provides for body movement
Muscle
1 Actin active sites are exposed, myosin binds and cross bridges are formed 2 When cross bridges form between myosin and actin, contraction begins 3 During the power (working) stroke, myosin pulls actin toward the center of the sarcomere 4 Cross bridge detachment occurs when ATP binds to myosin 5 Calcium ions are pumped back into the sarcoplasmic reticulum; without calcium present, actin active sites are blocked by tropomyosin and relaxation occurs
Muscle contraction involves the events of the cross bridge cycle and ends with muscle relaxation. Using the list given, arrange those steps in the correct sequence. (5 points)
Provides for body movement.
Muscular System
Once the muscle cell action potential is initiated, calcium ions are released from the sarcoplasmic reticulum. These calcium ions bind to troponin. With this binding, tropomyosin is pulled away from the active sites on actin. Myosin can bind with actin forming a cross bridge. A power stroke occurs and the myofilaments (actin and myosin) move towards the center of the sarcomere. Muscle contraction ends when the calcium ions are pumped back into the sarcoplasmic reticulum.
Once the action potential occurs in the sarcolemma, it spreads by moving down the T-tubules. What happens next? What is the correct order of events which result in skeletal muscle contraction? (4 points) Once the muscle cell action potential is initiated, calcium ions are released from the sarcoplasmic reticulum. These calcium ions bind to troponin. With this binding, tropomyosin is pulled away from the active sites on actin. Myosin can bind with actin forming a cross bridge. A power stroke occurs and the myofilaments (actin and myosin) move towards the center of the sarcomere. Muscle contraction ends when the calcium ions are pumped back into the sarcoplasmic reticulum. Once the muscle cell action potential is initiated, calcium ions are pumped back into the sarcoplasmic reticulum. These calcium ions bind to tropomyosin. With this binding, troponin is pulled away from the active sites on actin. Myosin can bind with actin forming a cross bridge. A power stroke occurs, and the myofilaments (actin and myosin) move towards the center of the sarcomere. The power stroke occurs releasing the neurotransmitter. When the muscle cell action potential occurs, calcium ions are released from the sarcoplasmic reticulum. The calcium ions bind to troponin. This pulls tropomyosin away from the binding sites on myosin. Actin can bind with myosin forming a cross bridge. The myofilaments (actin and myosin) move away from the center of the sarcomere duing the power stroke.
Considering the structural organization of the human body, which is the correct sequence from the most complex level to the simplest level of organization?
Organism, organ system, organ, tissue, cellular, chemical
The sensory (afferent) and motor (efferent) divisions are part of the
Peripheral nervous system
Which of the following are characteristics of a chemical synapse?
Release of neurotransmitter by exocytosis from the presynaptic neuron Receptors for the neurotransmitter are present on the postsynaptic neuron The synaptic cleft is a space separating the presynaptic and postsynaptic neurons
Provides for oxygen supply and carbon dioxide removal.
Respiratory System
You have a big exam coming up and you're anxious because you feel unprepared. You begin to breathe rapidly. Physiological changes begin occurring in your body. Which of the following correctly describes the physiological changes you are experiencing?
Respiratory alkalosis
The nervous system has 3 related functions. Indicate the logical order for these functions.
Sensory input, integration, motor response
The sources of energy used during short-duration exercise include creatine phosphate which quickly supplies energy for working a muscle at a very high rate, but lasts only 8-10 seconds. Glycogen is created a bit slower but can supply energy for about 90 seconds. Aerobic respiration kicks in within about two minutes of exercise and lasts for an unlimited time. https://www.sciencelearn.org.nz/resources/1920-energy-for-exercise (Links to an external site.)
Short answer question: Compare the sources of energy used during short-duration exercise to those used during longer periods of exercise. Include the timing involved is using each source of energy. (8 points) Be sure to use your own words. Do not use abbreviations. Include a citation for the reference (text or other sources) you used in formulating your response. If you do not include a citation, you will lose 2 points for this question.
During the Excitation-Contraction (EC) coupling a nerve fiber stimulates the skeletal muscle fiber causing contraction. The generation of the action potential begins with excitation by acetylcholine binding to a receptor triggering it. The action potential then goes along the sarcolemma and into the T-tubules. As it goes along the T-tubules, the change in voltage causes them to change shape. Calcium ions are triggered to be released by this shape change and the opening of the ion channel in the terminal cisterns of the sarcoplasmic reticulum, where the calcium then goes into the cytosol. In the cytosol it binds to troponin and stops the blocking caused by tropomyosin by binding to it. This changes its shape allowing the myosin binding sites to be revealed. Finally, contraction can occur after the myosin begins to bind to actin and form cross bridges. https://www.nature.com/scitable/topicpage/the-sliding-filament-theory-of-muscle-contraction-14567666/
Short answer question: Excitation-Contraction (EC) coupling involves a series of sequential steps. (10 points) Summarize the events during excitation-contraction coupling beginning with the generation of the action potential in the muscle fiber and ending in muscle contraction. Your answer should include the roles of each of the following:actinmyosintropomyosintroponincalcium ionsthe T-tubules of the sarcolemmathe terminal cisterns of the sarcoplasmic reticulum. Be sure to use your own words. Do not use abbreviations. Include a citation for the reference (text or other sources) you used in formulating your response. If you do not include a citation, you will lose 2 points for this question.
Once acetylcholine binds to its receptor it is then destroyed by acetylcholinesterase. Due to the toxin produced by the bacterium Clostridium tetanus not all of the acetylcholine will be destroyed promptly since there is a lack of acetylcholinesterase. This will lead to the prolongation of muscle contraction and symptoms like painful contractions and rigidity of skeletal muscles. https://pdb101.rcsb.org/motm/54 (Links to an external site.)
Short answer question: The bacterium Clostridium tetanus produces a potent toxin (poison) which causes the disease tetanus. This toxin destroys the enzyme acetylcholinesterase. The symptoms of tetanus result in painful contractions and resulting rigidity of skeletal muscles. Discuss how the lack of acetylcholinesterase would cause these effects. (5 points) Be sure to use your own words. Do not use abbreviations. Include a citation for the reference (text or other sources) you used in formulating your response. If you do not include a citation, you will lose 2 points for this question.
The four specific restorative processes that occur so muscle can return to its pre-exercise state are replenishment of oxygen reserves, the conversion of lactic acid into pyruvic acid, replacement of glycogen, and lastly ATP and creatine phosphate need to be synthesized again. Each process needs oxygen to be able to occur and without them glucose can not be made into glycogen and lactic acid can not be turned back into pyruvic acid. These are related to the Excess Postexercise Oxygen Consumption (EPOC) because as stated, without oxygen the four process cannot occur and during exercise we lose a lot of oxygen so in order for the processes to occur we need EPOC to make up for oxygen used during exercise. https://www.womenshealthmag.com/fitness/g30767966/epoc/ (Links to an external site.)
Short answer question: Vigorous athletic activity changes a muscle's chemistry. Muscle fatigue can also occur. Describe the 4 specific restorative processes that occur so the muscle can return to its pre-exercise state. Explain how these are related to Excess Postexercise Oxygen Consumption (EPOC)? (6 points) Be sure to use your own words. Do not use abbreviations. Include a citation for the reference (text or other sources) you used in formulating your response. If you do not include a citation, you will lose 2 points for this question.
Provides body framework for support and protection; produces blood cells.
Skeletal System
help maintain posture
Slow oxidative muscle fibers: (2 points) are best suited for sprinting help maintain posture are best suited for weight lifting
When an action potential travels along a neuronal membrane, which channels open first?
Sodium Ion
When the voltage-gated sodium channels open, what happens to the sodium ions?
Sodium Ions rush into the cell
To move your arm and hand to pick up the book, which nervous system is acting?
Somatic nervous system
What does the molecular similarity of stevia to glucose mean for the gustatory sense?
Stevia will bind to the glucose receptor in the taste buds which means that even though the glucose receptors aren't getting glucose, they are getting something similar so they will accept it and treat it as glucose.
If a neuron releases norepinephrine, which division of the peripheral nervous system is it a part of?
Sympathetic
Explain the All-or-None principle in nerve propagation. Describe the role of the threshold in this event.
The all-or-none principle basically says that no matter how strong a nerve response is, it is not equal to the strength of the stimulus. The threshold for the nerve response is what causes the nerve to respond. As soon as the threshold is passed, the nerve will fire.
The conducting or propagating region of the neuron that carries the nerve impulse away from the cell body/soma is called
The axon
Definition of homeostasis
The maintenance of a constant internal environment
To initiate skeletal muscle contraction, what happens first? (2 points)
The muscle must be stimulated by a nerve impulse
Definition of Stasis
The point at which two arguments meet, a condition in which things do not change, move, or progress.
How is the resting membrane potential established? Where is there a higher concentration of sodium ions? Where is there a higher concentration of potassium ions? Based on their concentration differences across the membrane, in which direction will sodium ions diffuse? Based on their concentration differences across the membrane, in which direction will potassium ions diffuse? What is the role of the sodium-potassium pump in maintaining the resting membrane potential (or compensating for the continual ion leakages into and out of the cell)?
The resting membrane potential is determined by the concentration of ions both inside and outside the membrane. The permeability of the membrane also has an effect on resting membrane potential. There is a higher concentration of sodium ions outside the cell membrane. There is a higher concentration of potassium ions inside the membrane. Sodium will go into the membrane and potassium will exit the membrane. The Sodium-Potassium pump will bring 3 sodium ions in the cell and let 2 potassium ions out.
Which statement about synapses is correct?
The synaptic cleft separates two neurons and prevents direct transmission of impulses between them
According to the sliding filament model of skeletal muscle contraction (2 points)
The thin actin filaments slide past the thick myosin filaments until the actin and myosin filaments overlap
Describe the regulation of blood glucose in relation to insulin release only. What type of feedback mechanism is involved? Explain your response.
There is a negative feedback mechanism involved when it comes to the regulation of blood glucose in relation to insulin release. A negative feedback mechanism is is a type of regulation in biological systems in which the end product of a process in turn reduces the stimulus of that same process. So, when it comes to regulating blood glucose (sugar), your pancreas will release insulin to reverse the effect that the extra sugar has on your body, and your body goes into homeostasis.
If the Na+ concentration intracellularly (inside) the red blood cell is 0.9% and the Na+ concentration in an intravenous (IV) solution is 2.0%, what will happen to the red blood cells as the solution flows into the blood?
They will shrink from loss of water
Troponin has 3 binding sites allowing it to bind to 3 different substances. Which of the following statements is correct? (2 points)
Troponin can bind to tropomyosin, actin, and calcium ions
The autoimmune disease multiple sclerosis (MS) results in the destruction of the myelin sheath. When this occurs, what will happen to nerve transmission and why?
When somebody gets MS, the immune system starts to attack the myelin sheath which is like a blanket that covers the nerves around your brain and spine. When the nerves are getting attacked, they have multiple ways of responding and they can alter your entire body. First of all, the nerve fibers will be damaged, and they will start to grow scar tissue. Also, the nerve transmission will slow down, or even halt which could cause conditions such as a droopy mouth or fatigue.
Lactic acid
When someone is exercising vigorously, there may not be enough oxygen available for oxidative phosphorylation. Instead, pyruvic acid is converted into (2 points) Citric acid Ketone bodies Glycerol Lactic acid
What type of reflex can protect your foot from further injury when this painful stimulus is sensed?
Withdrawal Reflex
For a neuron in a resting (polarized) state
a higher concentration of potassium ions is found inside the membrane
What does a ligand-gated channel require in order to open?
binding of a neurotransmitter
The sympathetic nervous system originates in the _______ region(s) of the spinal cord.
both thoracic and lumbar
During skeletal muscle contraction, which ions bind to troponin, moving tropomyosin and revealing the binding sites on actin?
calcium ions
Definition of homeo
combining forms
What is the function of the plasma/cell membrane?
controls what goes in and out of the cell
The activity of acetylcholine in a synapse is terminated by its ________
degradation on the postsynaptic membrane
Tactile sensation is a combination of touch, pressure, stretch, and vibration. Which of the following is most likely the receptor type that senses tactile stimulation?
mechanoreceptors
Neurons that transmit impulses only towards the central nervous system are
sensory (afferent) neurons