1. Which of the following is a non-invasive imaging technique that measures the blood flow and can be used to reveal the function of the human brain?
a) PET b) fMRI
c) CT d) EKG
d) EEG
2. Ca2+ ions are essential for
a) transmitter release at the synapse b) muscle contraction
c) maintaining the bone mass d) both a and b
e) all of the above
3. Which of the following brain regions plays a major role in vision?
a) temporal lobe b) parietal lobe
c) occipital lobe d) frontal lobe
e) olfactory lobe
4. It is likely that you will remember for the rest of your life the circumstances under which you first saw the shocking images of the terrorist attacks of 9/11/01. This is likely attributed to the activation of neurons in the
a) amygadala b) basal ganglia
c) brainstem d) hypothalamus
e) thalamus
5. Which of the following can be used to relieve pain?
a) a toxin (TTX) from the puffer fish b) a toxin (conotoxin) from cone snails
c) black widow spider venom d) curare
e) alpha-bungarotoxin
6. Rigor mortis is attributed to the lack of ______________________ molecules that are essential for the detachment of myosin from actin.
a) calcitonin b) troponin
c) ATP d) tropomyosin
e) myostatin
7. Clinical Depression is likely attributed to
a) a deficiency in serotonin b) a decrease in serotonin re-uptake
c) an increase in dopamine d) an increase in GABA
e) a deficiency in glycine
8. Which of the following changes in ion channel conductance in the postsynaptic membrane could result in an IPSP?
a) an increase in potassium channel conductance
b) an increase in calcium channel conductance
c) an increase in sodium channel conductance
d) a decrease in chloride channel conductance
e) None of the above
9. ______ cells, which are more abundant in the _________ of the retinal, are responsible for night vision.
a) Cone; periphery b) Cone; fovea
c) Rod; center d) Rod; periphery
e) Ganglion; fovea
10. Which of the following would happen during muscle contraction?
a) both A and I bands are shortened
b) both A band and sarcomere are shortened
c) both thin and thick filaments are shortened
d) the lengths of the A band and thin and thick filaments remain the same as when at rest
e) Z lines are shortened
11. Multiple sclerosis is due to damage to the
a) blind spot b) myelin sheath
c) fovea d) ligament
e) Organ of Corti
12. Which of the following is (are) involved in stress responses:
a) corticotropin-releasing hormone (CRH) b) ACTH
c) glucocorticoids d) adrenalin
e) all of the above
13. Which of the following hormones reduces urine volume?
a) oxytocin b) prolactin
c) ACTH d) thyroxine
e) vasopressin
14. Which of the following can prevent osteoporosis?
a) calcium b) vitamin D
c) exercise d) all of the above
e) none of the above
15. In comparison with fast twitch fibers, slow twitch fibers
a) have a low content of mitochondria b) primarily use anaerobic respiration
c) are large in diameter d) are fatigue-resistant
e) are red in appearance and are the dominant fibers found in the bicep muscle
Section II. Fill in the Blanks (Total 30 points, each correct answer is worth 3 pints).
1. A person with _______20____/______200________ vision is considered legally blind.
2. While you enter your answer to this question, your motor nerve terminals are releasing ______acetylcholine_____________ (name of a neurotransmitter) at the neuromuscular junction.
3. Non-steroid hormones bind to receptors on the target membrane and trigger the formation of a secondary messenger called ___cAMP___________________, which amplifies the hormone responses.
4. The repolarization phase of an action potential is caused by an increase in the conductance of_____K+________________ channels.
5. Artificial labor during childbirth can be induced by an injection of ___oxytocin_________________ (name of a hormone).
6. Parkinson’s Disease is due to a deficiency of ______dopamine___________________ (name of a neurotransmitter) in the basal ganglia.
7. After spinal cord injury, the inability of axonal regeneration is likely attributed to inhibitory molecules produced by _oligodendrocytes____________________ (name of a type of glial cells).
8. Right after you have an ice cream sundae and your blood glucose concentration is going over 120 mg/dL, ____insulin____________ (name of a hormone) will increase in order to restore the right level of glucose in your blood.
9. Blood stem cells can be produced by _red bone marrow_________________ inside the spongy bone.
10. Marathon running primarily uses the ___slow__________________ (slow or fast twitch muscle).
Section III. Short Answer (Total 20 points, each correct answer is worth 5 points). Please be sure to provide your reasoning for each answer, and limit your answers to the space provided.
1. Describe two major differences between type I and type II diabetes mellitus.
Type I, also called insulin-dependent or juvenile-onset diabetes (5-10% cases), is believed to be an autoimmune disease, in which the patient’s immune system attacks and destroys his/her own insulin-producing beta cells in the pancreas. As a result, the pancreas produces insufficient amount of insulin. The patient must take insulin daily to survive.
Type II, also called non-insulin-dependent or adult-onset diabetes, is the most common form of diabetes (90-95% cases). In type II diabetes, the body fails to respond to insulin effectively, which is attributed primarily to a reduction in the amount of insulin receptors or sensitivity. The risk factors include family history, obesity, and sedentary life-style.
2. Use a heart attack as an example to define “referred pain.”
During a heart attack, the patient would experience pain in the left shoulder and arm, in addition to the chest. This is because neurons in the brain receive sensation from the skin in those areas, instead of localizing the pain at the heart.
3. Why is it dangerous to eat clams harvested from an area affected by the red tide?
The red tide is attributed to the over growth of certain algae, which produce saxitoxin. Because saxitoxin blocks voltage-gated Na+ channels, which are essential to action potential production, eating clams that are contaminated with saxitoxin could result in paralysis, called paralytic shellfish poisoning.
4. What is the rationale of using COX2 inhibitors, instead of aspirin, as a painkiller? What is the possible adverse effect of using COX2 inhibitors?
Aspirin: acetylsalicylic acid; pain reliever; anti-inflammation; blocks COX-1 and COX-2.
Cyclooxgenase (COX) produces prostaglandin, which contributes to inflammation and pain. COX-1 in stomach helps mucus formation. Thus, aspirin can irritate stomach and cause bleeding. COX-2 inhibitors do not block COX-1 and thus would not irritate stomach and cause bleeding.
COX-2 inhibitors also block prostacyclin, which normally prevents blood clots. Thus, COX-2 inhibitors may result in blood clots in the coronary artery and heart attacks (or stroke).
Section IV. Essay Questions (Total 20 points).
1. (10 points) In a neural circuit as shown in the diagram, neuron “c” receives innervation from both neuron “a” and neuron “b”. Neuron “c” in turn innervates a skeletal muscle fiber. The threshold for triggering an action potential in neuron “c” is 10 mV more positive than the resting potential.
(A) (5 points) Let’s assume that supra-threshold stimulation of neuron “a” and neuron “b” produces, respectively, an 8 mV EPSP and 5 mV EPSP in neuron “c”. What kind of potential changes, if any, would you expect to find in muscle fiber when both neurons a and b fire an action potential simultaneously? Be sure to explain your reasoning for the answer.
Answer:
The muscle fiber will fires an action potential.
Due to the summation of 8 + 5 mV = 13 mV, which is above the threshold of 10 mV, neuron “c” would fire an action potential, which would then propagate to the nerve terminal. This would result in the release of acetylcholine, which binds acetylcholine receptors at the neuromuscular junction andtriggers an action potential in the muscle fiber.
(B) (5 points) Let’s assume that in the above circuit supra-threshold stimulation of neuron “a” and neuron “b” produces, respectively, an 8 mV EPSP and -5 mV IPSP in neuron “c”. What kind of potential changes, if any, would you expect to find in muscle fiber when both neurons a and b fire an action potential simultaneously? Be sure to explain your reasoning for the answer.
Answer:
No potential changes would occur in the muscle fiber.
This is because the summation of 8-5 mV = 3 mV, which is below the threshold of 10 mV, and neuron “c” would not fire an action potential at all. Without an action potential, the nerve terminal will not release acetylcholine and thus muscle fiber will not show any potential changes.
2. (10 pts) In a neurological test, a split-brain patient is blindfolded. If you present a banana to hisright hand, and an orange to his left hand, can the patient name the banana, the orange, or both correctly? Please be sure to provide your reasoning, and discuss the implication of the test result.
The patient can name the “banana” correctly, but will not be able to name the “orange” at all.
Since the information from the right hand, such as a banana in this case, will reach to the left cerebral hemisphere, where the language center resides, the patient should be able to name the banana correctly. In contrast, the information from the left hand, in this case, an orange, will reach to theright cerebral hemisphere. But in the split-brain patient, the corpus callosum, which normally communicates both hemispheres, was severed. Thus, the patient cannot convey the information from his right-brain to his left-brain. Without information reaching to the language center in the left-brain, the patient just cannot name the “orange” even though he is well aware of what he is holding in his left hand.
This result suggests that the human left-brain governs language, and that corpus callosum plays a key role in communication between the left and the right brain. Other tests also indicate that the right-brain is good at spatial tasks and face recognition.