(Here you will find answer keys for homework or quizzes as well as unedited responses on exams from your classmates)
Quiz 1 Answer Key:
1. The Na/K ATPase pump is an example of how molecules are transferred across the phospholipid bilayer by the process of
a. simple diffusion
b. facilitated transport
c. secondary active transport
d. primary active transport
2. ______________________________ + Interstitial Fluid (ISF) = Extracellular Fluid (ECF)
3. Which of the following subcellular structures is responsible for oxidative phosphorylation?
a. plasma membrane
4. T or F (please circle)
All cells have a negative resting membrane potential and thus have the capacity to generate an action potential.
5. Osteocytes and chronodytes are part of which tissue classification?
a. smooth muscle
6. If you had a tick on your hand (assume it has 300 mOsm internal fluids) and you wanted to kill it by lysis, you would put your hand into which solution?
a. 400 mM of glucose
b. 200 mM of NaCl
c. 100 mM of CaCl2
d. 50 mM glucose
e. None of these will work and you’d have to crush the tick to kill it
7. T or F (please circle)
If you stimulated a nerve bundle during the depolarization phase of a spiking action potential, none of the nerves would fire an action potential because all would be in absolute refraction.
8. The conduction velocity or length constant of an axon is based upon what two variables? (Either words or symbols are fine)
ANSWER: Resistance of the membrane (Rm) and Resistance of the internal axoplasm (Ri)
9. Name two major characteristics of an action potential?
ANSWER: (many possibilities!) – All or none, non-decrimenting, travels with specific conduction velocity, is derived by underlying ion channel activity, rapid and transient change in the resting potential, etc.
Use the following saline composition and permeabilities to answer the next two questions:
External K = 40 mM
Internal K = 300 mM
External Na = 330 mM
Internal Na = 55 mM
Pk at rest = 10
Pk at activation = 20,000
PNa at rest = 0.1
PNa at activation = 10,000
10. Calculate the voltage for the peak of the anticipated action potential for a nerve fiber in this solution. SHOW ALL WORK
ANSWER: ENa = 60/1 * log [(330/55)] = 46.689 = 47 mV
11. Calculate the voltage for the resting membrane potential for this nerve fiber. SHOW ALL WORK
ANSWER: Em = 60 log [(10)(40) + (0.1)(330)] / [(10)(300) + (0.1)(55)] = -50.4857 = -50.5 mV
Hurricane Irma Bonus: For your calculation in 10-11, what is this nerve’s threshold?
SHOW ALL WORK
Take delta of the two value of Em and ENa and then multiple by .15 (Threshold) = 47 + 50.5 = 97.5(.15) = 14.625 = 14.6 mV is needed to spike a full AP. If resting is -50.5, then would have to come up to -35.9 mV to fire fully.
Quiz 2 Answer Key:
1. Which of the following types of muscles are striated and involuntary?
d. b and c
e. a and b
f. none of the above
2. A single muscle CELL is known as
a. a sarcomere
b. a myofibril
c. one actin and one myosin filament
d. a motor unit
e. a muscle fiber
3. Action potentials move perpendicular to the muscle fibers by entering the transverse tubules that are located where along the sarcomere?
a. A band
b. Z band
c. M band
d. I band
e. Z and I bands
f. A and I bands
4. Which of the following “contractile proteins” functions to block the thick filament from accessing a binding site to form a cross bridge but does not physically bind calcium?
5. In relation to skeletal muscle mechanics, during which phase of the twitch would calsequestrin have its highest activity?
a. latency period
6. T or F (please circle)
The white matter is responsible for integrating reflex activity using polysynaptic and monosynaptic connections of afferent and efferent neurons, respectively.
7. Which of the following does not mediate or assist in smooth muscle contraction of your arteries?
a. inositol 1,4,5-trisphosphate
b. dense bodies
d. sarcoplasmic reticulum
e. ALL are helpful in smooth muscle contraction
8. During a skeletal muscle contraction, the length of the sarcomere shortens due to a decrease in size of ALL but which band?
a. A band
b. Z band
c. H band
d. I band
e. All of the above will shorten
9. If the cross bridge cycle was in a stage where there was no calcium, the orientation of the myosin head was at 90 degrees in relation to the tail of the molecule, and there was ATP available, then the muscle would be in which stage of contraction?
a. the actin and myosin would be touching each other
b. it would be in the power stroke
c. actin and myosin would be detached and ATP would undergo hydrolysis
d. it would be in a rigor mortis locked complex
10. Which of the following activities is performed principally by the somatic nervous system?
a. beating of your heart
b. bowel movements
c. running up the stairs
11. Which portion of the spinal column has emerging spinal nerves that would innervate the chest region?
e. dorsal root ganglion
Take Home Quiz 3
1. If blood is moving out of the lungs, it will
a. enter the pulmonary artery
b. pass through the pulmonary semilunar valve
c. reenter the heart at the level of the left atrium
d. it will leave the systemic circulation through the superior vena cava
2. Which of the following ion channels is most pertinent for the difference in the cardiac action potential shape (in comparison to skeletal) initiated in the walls of the ventricle?
a. fast inward sodium channels
b. t-type calcium channels
c. l-type calcium channels
d. If sodium channels
e. delayed rectifier potassium channels
3. If you can hear the mitral valve
a. then you must have placed the stethoscope at the second right intercostal
b. the heart must be it the relaxation phase or diastole cycle
c. it will be in synchrony with the QRS spectrum of the electrocardiogram
d. blood should have just moved from the right atrium to the right ventricle
e. the blood on this side of the heart would be deoxygenated
4. Name one of two holes or pathways that blood might travel after birth if there is a septal defect?
ANSWER: foramen ovale and ductus arteriosis
5. An irregular heart beat in which a patient can live for several years and not be cognizant of a problem is
a. ectopic pacemaker condition
b. ventricular tachycardia
c. third degree AV block
d. atrial fibrillation
6. Which type of blood vessel or structure has stretch receptors, can withstand 100 mm Hg pressure, has elastic recoil, and helps to assist the pumping action of the heart?
b. ring muscles
7. T or F (please circle) The Law of LaPlace states that the stress on a vessel will decrease when the width of the smooth muscle running circumferentially around the blood vessel increases.
8. Which of the following type of muscle is neurogenic and has economical cross-bridge cycling due to phosphorylation of the myosin tail?
a. pacemaker activity
b. slow wave potentials
c. single unit smooth
d. multi unit smooth
9. When blood moves between the left atria and left ventricle
a. the pulmonary semilunar would be open
b. the timing would be in register with the T wave
c. the blood would be deoxygenated
d. one would hear the S1 on the phonocardiogram
10. If you had a patient with a total circulating blood volume of 6L (per minute) and had a cardiac rate of 90 beats/min (almost tachycardic), how much blood would be pumped out of their ventricle per beat?
a. 54 mls
b. 540 mls
c. 67 mls
d. 15 mls
e. 0.015 L
11. What was your blood pressure (BP) at the Ocala Publix _____________________?
Given this BP, calculate your mean arterial pressure ____________________________
(Show your work here)
ANSWER: Mine at Premeire was 95/63….PP = 95-63 = 32. MAP = 63 + 1/3(32) = 74 mm Hg
Quiz 4 Answer Key:
1. Which of the following muscle would be used with passive exhalation and not recruited for only a forced exhalation requiring energy?
a. internal intercostal
b. external abdominal oblique
c. transversus abdominus
d. rectus abdominus
ANSWER: None! My bad, meant to type ‘external’ intercostal. J Everyone got this updated on their Canvas grade.
2. When carbon monoxide (CO) associates with the respiratory pigment hemoglobin it is called
3. When sampling the new planet Vena, scientists found that the total atmospheric pressure was 400 mm Hg and that martians use the gas Wr to breath. Calculate the partial pressure for Wr on Vena if it comprises 14% of the atmosphere on the planet? ____________________________
ANSWER: 400 * 0.14 = 56 mm Hg Wr
4. Which of the following cellular environments would promote an earlier dissociation of oxygen from hemoglobin (dump O2 sooner)?
a. hypoventilation or choking
b. severe body heat loss
c. any condition inducing a left Bohr shift
e. a blood transfusion
5. Carbon dioxide is transported back to the lungs in several forms, the most predominant being
a. free, dissolved carbon dioxide
e. carbonic acid
ANSWER: b. (This was from an old mcat test btw)
6. Write out the carbonic anhydrase shift equation, including the enzyme that is involved =
H2O + CO2 >>>>>carbonic anhydrase >>> H2CO3 >>>>> H+ + HCO3-
7. If your patient weighed 100 kg and was bringing in 800 ml of fresh air with each breathe, what should be the level of vital capacity measured if their ERV was 1.4 L and their IRV was 3 L?
(Show all work)
100 kg * 2 ml = Vd = 200 ml
TV = Vd + Va
TV = 200 ml + 800 ml = 1000 ml or 1L
VC = ERV + IRV + TV
VC = 1.4L + 3L + 1 L = 5.4L
8. T or F (please circle)
Air falls down pressure gradients during inspiration and expiration according to Haldene’s Law.
9. If you had a TLC of 8L and the standard 0.5L reserve as your RV, could a VC be calculated?
If yes, VC = _______________________________ If not, what variables are you lacking to make the calculation?
(Show all work)
TLC = VC + RV
8 = X + 0.5
X = 7.5L
10. Which lung disease can be attributed to the constriction of the bronchioles, causes air trapping, has an elevated RV and normal TLC and a reduced VC, and can be treated using drugs that cause vasodilation?
b. pulmonary fibrosis
c. not a lung disease, but too little exercise
e. not a lung disease, but attributed to reduced elasticity of old age
11. How many molecules of oxygen bind Hb when it is fully saturated?
First Hour Exam Example Essays (unedited) from your Colleagues:
By: Zoe Kinkead
The fluid-mosaic model describes the phospholipid bilayer as “proteins in a sea of fat.” The fluid portion of the model comes from the moving hydrophobic carbon chains (tails) on the phospholipid. The mosaic portion comes from the wide variety of proteins embedded within the membrane. Components of the bilayer include cholesterol (regulates fluidity), phospholipids (polar hydrophilic head and 2 hydrophobic tails), extrinsic/intrinsic/integral membrane proteins, glycol proteins (function in immunity), protein scaffolds (for protein-protein interactions), and the cytoskeleton. The membrane proteins can serve as hormone receptors (extrinsic), ion channels (integral) or G-Protein receptors (intrinsic). A cell physiologically requires a membrane to 1. Compartmentalize function, 2. Serve as a selectivity permeability regulator of what gets through the membrane, and 3. It acts as a capacitor (stores charge) and therefore affects cells’ electrical activity and excitability.
By: Nicholas Johnson
Electrical synapses would be useful in the cardiac muscle. It is paramount that the cardiac muscles all contract at the same time, so it is important that all the muscles be synchronized. Where as in a chemical synapse, the response is slower and is not responsible for synchronization. Chemical synapses have a synaptic cleft where neurotransmitters are released onto the post-synaptic cell membrane to carry on the action potential to the next neuron. Whereas electrical synapses use a gap junction, in which the electrical signal can “jump” from neuron to neuron, because the gap junctions are so tight.
By: Guivens Joseph
Two diseases that affect a large population are Parkinson’s disease (PD) and Alzheimer’s disease (AD). PD is due to a loss of dopaminergic fibers while AD is due to the degeneration of cholinergic fiber endings due to β-amyloid proteins. PD affects the basal nuclei, while AD affects the hippocampus and amygdala. In PD, the basal nuclei loses its inhibitory function due to a lack of dopamine, while in AD there can be a lack of acetylcholine (Ach) itself or a lack of Ach-R (receptors). There is no genetic predisposition for PD, but AD has a genetic predisposition in the genes ApoE3 and ApoE4. Both diseases have environmental factors that influence them. Lead/tin results in neural death in PD, while there’s a high concentration of aluminum in patients with AD.
By: Karleigh Johns
Squids developed larger diameter axons. This decreases the internal resistence (ri) and increases the conduction velocity of the action potential. Since no myelin is present on a squid axon, more ATPase pumps are needed to extend down the whole axon, which is energy taxing. The action potential for squids are slower due to the lack of myelin and nodes of Ranvier. For the dolphin, myelin is present on the axon, which increases the membrane resistance (rm) and increases the conduction velocity. Having myelin allows for internodes and nodes of Ranvier. Saltatory conduction takes place as electrical signal, jumps from node to node, where the sodium/potassium ATPase pumps are present. Having less ATPase pumps present allows for efficient use of ATP. Local circuits are used to create disturbances to allow an action potential to occur if it reaches threshold. All action potentials have a latency period (delay), are unidirectional, and follow the all-or-none rule.
By: Madison Schenk
The humonculus is a cartoon figure of a man that can be graphically represented upon somatotopic maps. It tells us about the distribution of sensory inputs and outputs in the primary motor cortex and secondary sensory cortex. This cartoon shows us that distribution of sensory inputs and motor outputs are not even throughout the entire body and certain areas are more sensitivity to sensory stimuli than others. This is represented on the cartoon as areas of the body which are larger than normal size (i.e. large hands and lips.)
Second Hour Exam Example Essays (unedited) from your Colleagues:
By: Emily Bohner
The thigh is a skeletal muscle, so cross bridge formation begins by recruitment of Ca2+ from the sarcoplasmic reticulum (SR), a specialized form of the endoplasmic reticulum, This Ca2+ then binds to troponin, which pushes tropomyosin out of the way, exposing the myosin binding site on actin and allowing a cross bridge formation. After the power stroke, Ca2+ is sequestered back into the SR by calsequestrin and myosin returns to rest. This process is slightly different in the aortic arches, since they are made up of smooth muscle, and smooth muscle lacks troponin. Instead Ca2+ forms a complex with calmodulin, which phosphorylates tropomyosin, and exposes myosin binding sites in a process called the “latch phenomenon”. Also, the major source of Ca2+ in smooth and cardiac muscle is voltage-gated Ca2+ channels, with a minor amount coming from the SR. Finally, the left atria is a cardiac muscle, so the process differ slightly from skeletal, as Ca2+ is considered “L-type” to innervate the absolute refractory period, preventing tetany.
By: Adrien Thokalath
Action potentials generated in the thigh are due to acetylcholine (ACh) being released, thus activating ACh receptor-gated channels for Na+, depolarizing the membrane. The refractory period is relatively short so summation can occur. Resting membrane potential is around -70mV. The summation due to a small refractory period means that tension can be built. Action potentials within the hears have two situations, fast and slow. The slow has relatively the same refractory period as skeletal muscle, however it depolarizes due to If (funny) channels, and eventually with the help of transient Ca2+ channels. The resting potential is around -60mV. Fast AP’s in the heart are very different. The resting potential is around -90mV and the refractory period is long and exhibits a plateau due to L-type Ca2+ channels in balance with K+ efflux. The depolarization and repolarization steps in fast AP are very steep (fast), hence the name.
By: Alexis Moffa
Heart disease causes 1 in 3 deaths in the USA. Congestive Heart Disease (CHD), or Myocardial Infarction (MI), can be diagnosed by looking at an EKG to observe abnormality of the cardiac cycle or by the patient complaining of left sided pain, or angina. On the EKG, the doctor can see a depressed S-T region. Treatments for MI, from least to most invasive, starts with taking aspirin (blood thinners). Nitroglycerine can also help alleviate the pain. More invasive is angioplasty, that sends a balloon up a vessel and inflates the artery, or a stint can be put in to also widen the artery. Another treatment is scraping the plaque that causes atherosclerosis. This procedure is not recommended because it can cause even further damage or create a future embolism from the loose plaque. The last option would be bypass surgery.
By: Shreyas Garimella
There are three types of blood vessels: arteries, veins, and capillaries. Arteries are thick and muscular, and can withstand 100-110 mmHg of pressure. They also have tunica, in which plaques can form. Veins, on the other hand, are thinner and less muscular, and can withstand a pressure of about 30mmHg. Arteries transport blood from the heart to the organs, while veins transport deoxygenated blood back to the heart. Capillaries are small and numerous, and facilitate the exchange of nutrients, gasses, etc. A plaque starts to form in the tunica of arteries, irrespective of diet. A diet high in LDL can, however cause a plaque to form faster. A Plaque can travel and block vessels, leading to heart disease. The ensuing hypertension may be detected using blood pressure tests or as a heart murmur, which is when there is turbulent instead of laminar blood flow. The Reynold’s# of blood flow would be increased, greater than 3000. One potential treatment are blood thinners, which can help restore laminar flow. Another, potential treatment is surgery to remove the plaque, a third would by bypass surgery.