Midterm 1

Multiple choice: As always, choose the best answer for each multiple-choice question.Answer on your scantron form.Each question (except #1) is worth 3 points.

1. Fill in your scantron form:  (1 point)
   • Write and bubble in your name in the upper left (last name first).
   • If you wish to retrieve your exam score through the course web site, write and bubble in a secret code (i.e. a password) in the "Special Codes" section.  Be sure you remember it!
   • Follow any additional instructions provided in class.
   • Sign your form in the upper right.
   1. I promise I did everything above.
   2.  – e.  I've been told to skip questions I don't understand.
       
2. Which of the following would fall into the category of the "internal environment" of the body?
   1. Intracellular fluid
   2. Interstitial fluid
   3. Extracellular fluid
   4. a. and b.
   5. b. and c.
       
3. In an open system, which of the following would have to occur if the level of X was being regulated?
   1. An increase in the rate of input of X would have to be matched by a decrease in the rate of output.
   2. An increase in the rate of input of X would have to be matched by an increase in the rate of output.
   3. X could only enter the system.
   4. X could only leave the system.
   5. X could neither enter nor leave the system.
       
4. A Donnan equilibrium is best described as the condition in which
   1. diffusion cannot take place because a membrane is impermeable to all solutes.
   2. two solutions are isosmotic.
   3. an animal is homeostatic.
   4. a particular physiological variable has the same value in an animal as in the surrounding environment.
   5. there is no net diffusion due to a balance of concentration and charge differences.
       
5. Secondary active transport involves
   1. One channel protein
   2. One carrier protein.
   3. Two channel proteins.
   4. Two carrier proteins.
   5. One channel and one carrier protein.
       
6. The movement of water across a cell layer such as an epithelium can be accomplished by
   1. the active transport of water molecules by carrier proteins known as porins.
   2. the creation of localized regions of high osmolarity by the active transport of ions.
   3. creating temperature differentials in the water on either side of the epithelium.
   4. Two of the above.
   5. None of the above.
       
7. A primary system of nervous control of involuntary activities within the body is the
   1. afferent nervous system.
   2. somatic nervous system.
   3. parasympathetic nervous system.
   4. Two of the above.
   5. None of the above.
       
8. The normal resting membrane potential of most mammalian cells (including neurons) is
   1. between –170 and –100 mV.
   2. between –100 and –30 mV.
   3. between –30 and +30 mV.
   4. between +30 and +100 mV.
   5. between +100 and +170 mV.
       
9. The generation of the membrane potential in most cells results in large part from which of the following?
   1. Relatively high [K⁺] inside the cell and high [Na⁺] outside the cell, with greater permeability of the membrane to K⁺ than Na⁺.
   2. Relatively high [K⁺] inside the cell and high [Na⁺] outside the cell, with greater permeability of the membrane to Na⁺ than K⁺.
   3. Relatively high [K⁺] outside the cell and high [Na⁺] inside the cell, with greater permeability of the membrane to K⁺ than Na⁺.
   4. Relatively high [K⁺] outside the cell and high [Na⁺] inside the cell, with greater permeability of the membrane to Na⁺ than K⁺.
   5. Rubbing the cells together so they build up static charge.
       
10. In a graded potential, the cell membrane
    1. shows a variable degree of depolarization depending on the strength of the stimulus.
    2. shows a variable degree of depolarization, but this does not depend on the strength of the stimulus.
    3. shows a stereotyped amount of depolarization regardless of the stimulus strength.
    4. can never hyperpolarize.
    5. does not depolarize at all.
        
11. Which of the following best describes what would happen to the voltage-gated sodium channels in a neuron if the voltage were raised from resting to above threshold and then held above threshold indefinitely.
    1. The channels would open and stay open.
    2. The channels would open, close and then open again.
    3. The channels would open, and then close and stay closed.
    4. The channels would never open.
    5. Neurons don't contain voltage-gated sodium channels.
        
12. In chemical synapses, neurotransmitter release is triggered most directly by which of the following?
    1. Opening of voltage-gated sodium channels.
    2. Opening of voltage-gated potassium channels.
    3. Opening of voltage-gated chloride channels.
    4. Opening of voltage-gated calcium channels.
    5. Opening of voltage-gated acetylcholine channels.
        
13. If the result of neurotransmitter reception by the postsynaptic neuron is inhibitory, this means
    1. the postsynaptic membrane potential has become more positive.
    2. the postsynaptic membrane potential has become more negative.
    3. the postsynaptic membrane potential has become easier to change.
    4. the postsynaptic membrane potential has become harder to change.
    5. the postsynaptic neuron is instantly killed.
        
14. If a postsynaptic neuron is connected to only one presynaptic neuron, which of the following can it experience with regard to postsynaptic potentials?
    1. Temporal summation.
    2. Spatial summation.
    3. Both temporal and spatial summation.
    4. Neither temporal nor spatial summation.
    5. Spatio-temporal geometric integration.
        
15. Cholinergic receptors are activated by
    1. serotonin
    2. acetylcholine
    3. GABA
    4. epinephrine
    5. endorphins
        
16. Which of the following would always be an interoceptive receptor?
    1. A chemoreceptor.
    2. A mechanoreceptor.
    3. A proprioceptor.
    4. A thermoreceptor.
    5. A photoreceptor.
        
17. Generally, the receptor membrane region of a sensory neuron
    1. exhibits no direct response to the environmental stimulus.
    2. exhibits a graded response in membrane potential in response to the environmental stimulus.
    3. exhibits action potentials at a rate proportional to the environmental stimulus.
    4. exhibits action potentials with an amplitude proportional to the environmental stimulus.
    5. exhibits action potentials with a duration proportional to the environmental stimulus.
        
18. Which of the following is true with regard to lateral inhibition?
    1. It increases the sensitivity of receptor membranes in the stimulated sensory cells.
    2. It decreases the sensitivity of receptor membranes in the "lateral" sensory cells.
    3. It increases the number of action potentials in the postsynaptic neuron connected to the stimulated cell.
    4. It decreases the number of action potentials in the postsynaptic neurons connected to the "lateral" sensory cells.
    5. It eliminates all sensory sensation over a wide region.
        
19. Which of the following is true with regard to taste and olfactory receptors?
    1. Individual taste and olfactory receptors respond to only one tastant or odorant.
    2. Individual taste receptors respond to only one tastant but olfactory receptors respond to more than one odorant.
    3. Individual olfactory receptors respond to only one odorant but taste receptors respond to more than one tastant.
    4. Individual taste and olfactory receptors respond to more than one tastant or odorant.
    5. The reason we have nose hairs but not tongue hairs is that olfactory receptors have "cilia" while taste receptors do not.
        
20. When the streocilia or kinocilium of hair cells are bent
    1. no change in membrane potential occurs.
    2. no change in membrane potential occurs if the "cilia" bend one way, but depolarization occurs if they bend the other way.
    3. no change in membrane potential occurs if the "cilia" bend one way, but hyperpolarization occurs if they bend the other way.
    4. the membrane depolarizes if the "cilia" bend in either direction.
    5. the membrane depolarizes if the "cilia" bend one way, but hyperpolarizes if they bend the other way.
        
21. Which of the following correctly describes part of the series of events that occurs when a photon strikes a rod cell in the eye?
    1. Retinal changes from the cis to trans form; conversion of cGMP to 5'-GMP by phosphodiesterase opens Na⁺ channels.
    2. Retinal changes from the trans to cis form; conversion of cGMP to 5'-GMP by phosphodiesterase opens Na⁺ channels.
    3. Retinal changes from the cis to trans form; conversion of cGMP to 5'-GMP by phosphodiesterase closes Na⁺ channels.
    4. Retinal changes from the trans to cis form; conversion of cGMP to 5'-GMP by phosphodiesterase closes Na⁺ channels.
    5. It feels like someone shoved a red-hot needle into your eye.
        
22. A chemical messenger that diffuses back to and acts on the same cell that released it is known as a(n)
    1. glandular hormone.
    2. neurohormone.
    3. exocrine product.
    4. autocrine agent.
    5. paracrine agent.
        
23. Hormones that activate intracellular receptors include
    1. peptide hormones and prostaglandins.
    2. peptide hormones and epinephrine.
    3. peptide and thyroid hormones.
    4. steroid hormones and prostaglandins.
    5. steroid and thyroid hormones.
        
24. The release of the hormones epinephrine and norepinephrine from the adrenal medulla is under neural control.  These hormones are considered
    1. glandular hormones.
    2. neurohormones.
    3. neurosecretory hormones.
    4. exocrine products.
    5. autocrine agents.
        
25. Cortisol helps us survive stressful situations by
    1. mobilizing energy stores.
    2. boosting the immune system.
    3. giving us amazing spider powers.
    4. a. and b.
    5. All of the above.
        
26. Which of the following best describes what occurs with the growth of long bones during an individual's lifetime?
    1. Growth rate of these bones is determined by the amount of growth hormone, and growth stops in adults because growth hormone is no longer released.
    2. Long bones grow in children and adolescents because of moderate levels of growth hormone, then high levels of GH cause the bones to stop growing.
    3. Sex hormones promote faster growth in adolescents, but increased growth hormone causes the long bones to stop growing.
    4. Sex hormones promote increased growth hormone release in adolescents, but then these sex hormones cause the long bones to stop growing.
    5. Adolescents stop growing as soon as sex hormone levels increase.
        

Short answer:   Write a concise answer to each of the following questions.  Your answers should fit in the spaces provided.  Each question is worth 4 points.

27. As a fun-spirited practical joke, you implant a small, remote-controlled heating coil into the blood vessel entering the hypothalamus of your roommate.  Assuming he has a normal temperature setpoint of 37°C, what physiological responses would likely occur if you heated the blood entering the hypothalamus to 38°C?
    
    
    
    
    
    
    
    
     
28. A 0.5 molar solution of sucrose and a 0.5 molar solution of glucose are separated by (what else?) a membrane, permeable to water but not sugars of any kind.  Sucrose is a disaccharide, a single molecule made up of one glucose and one fructose (another sugar) joined together.
    1. Will there be any movement of water between the two volumes?  Why or why not?
       
       
       
       
       
        
    2. You now add the enzyme sucrase to the sucrose solution, which splits the sucrose into glucose and fructose.  Will there be any movement of water between the two volumes under these new conditions?  Why or why not?
       
       
       
       
       
       
        
29. Describe the process of saltatory conduction in a myelinated axon, in comparison to conduction in an unmyelinated axon.  You do not need to discuss all the specifics of action potential generation.
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
     
30. Discuss the cause and effects of an increase in calcitonin levels in the blood.
    
    
    
    
    
    
    
    
    
    
    
    
     
31. Shown below is the strength of a stimulus affecting both a tonic and phasic receptor.  On the lower graph, use vertical lines to indicate the relative frequency of action potentials for each receptor type as the stimulus changes.  You may also include notes explaining what is occurring if desired.
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
     
32. Fill in the following table for the hypothalamic-pituitary system with the appropriate hormones or effects.  (Note that this is not a complete table.)  Be sure to use the full names of each hormone, not the abbreviations.

Hypothalamus		Anterior Pituitary		Target Organ/Tissue (and Effect)
				Adrenal cortex (Cortisol release)
		Prolactin		Breasts (Milk production)
Growth h. releasing h.		Growth hormone
Dopamine