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Basic Principles of HUman Philology

Terms in this set (39)

Homeostasis is defined as

1. the combination of growth, self-repair, and energy release

2. a condition in the body that does not involve fluctuation.

3. the production of energy by cells.

4. an amplification of deviation from the normal range.

5. the maintenance of a relatively constant environment within the body.
5. the maintenance of a relatively constant environment within the body.
Which of the following occur as part of the body's negative feedback loop when exposed to cold temperatures?

1. Goosebumps appear and hair stands up to create a boundary layer of warm air near the surface of the skin

2. The brain triggers the skeletal muscle to randomly contract to start shivering and generate additional heat

3. The brain signals the blood vessels near the surface of the skin to vasoconstrict

4. The brain signals the blood vessels near the surface of the skin to vasodilate

5. a, b, and c

6. a, b, and d
5. a, b, and c
Which of the following occur as part of the body's negative feedback loop when exposed to hot temperatures

1. Sweat glands are activated to increase their output

2. The brain signals the blood vessels near the surface of the skin to vasoconstrict

3. The brain signals the blood vessels near the surface of the skin to vasodilate

4. a and b

5. a and c
5. a and c
Which of the following statements regarding negative feedback is false?

1. Three components of the negative feedback mechanism are the receptor, control center, and the effector.

2. Most systems of the body are regulated by negative-feedback mechanisms.

3. Negative feedback means that any deviation from the set point is further amplified to maintain homeostasis.

4. One example of negative feedback is the control of blood pressure within a normal range
3. Negative feedback means that any deviation from the set point is further amplified to maintain homeostasis.
Which of the following statements regarding positive feedback is not correct?

1. Positive feedback is rare in healthy individuals and most physiological systems are more likely to be regulated by negative feedback.

2. Uterine contractions during childbirth is an example of positive feedback.

3. Positive implies that when a regulated variable deviates outside of the normal range, the body's response is to cause the deviation to become greater.

4. If blood pressure decreases and negative feedback is not able to maintain homeostasis, positive feedback will cause blood pressure to increase.
If blood pressure decreases and negative feedback is not able to maintain homeostasis, positive feedback will cause blood pressure to increase.
Put the following negative feedback events in the correct order.

1. If necessary, the control center causes an effector to respond.

2. The control center evaluates the value of the variable compared to the set point.

3. Information about the variable is sent to the control center.

4. A receptor monitors a regulated variable.

5. The effector produces a response that maintains homeostasis.
4,3,2,1,5
When a red blood cell is placed in hypotonic (very dilute) solutions of NaCl:

1. water leaves the cell, and the cell shrinks.
2. water leaves the cell, and the cell swells.
3. water enters the cell, and the cell shrinks.
4. water enters the cell, and the cell swells.
4. water enters the cell, and the cell swells.
When a red blood cell is placed in hypotonic (very dilute) solutions of NaCl:

1. sodium ions rush into the cell, down the concentration gradient.

2. sodium ions rush out of the cell, down the concentration gradient.

3. some sodium ions may leave the cell.

4. some sodium ions may enter the cell.
3. some sodium ions may leave the cell.
When a red blood cell is placed in isotonic solutions of NaCl:

1. water enters the cell more quickly than it leaves, so the cell swells and bursts.

2. water enters and leaves the cell at the same rate, so the cell neither swells or shrinks.
2. water enters and leaves the cell at the same rate, so the cell neither swells or shrinks.
Muscle tension can be increased with _________, which involves increasing the frequency of stimulation of the muscle fibers, as well as with __________, which involves increasing the number of motor units and muscle fibers contracting.

1. reinforcement; gradient change

2. gradient change; summation

3. summation; recruitment

4. recruitment; communal change
3. summation; recruitment
Predict whether each activity would primarily utilize fast-twitch or slow-twitch muscle fibers.

1. Long-distance jogging ___________
2. Weightlifting ________________
3. Sprinting ____________
4. Biking twenty miles on flat ground ____________
1. Slow-twitch
2. Fast-twitch
3. Fast-twitch
4. Slow-twitch
Hypertrophy of skeletal muscles from weightlifting is caused primarily by an increase in the

1. size of muscle fibers
2. number of mitochondria within the muscle fibers
3. number of nuclei within the muscle fibers
4. number of motor units and muscle fibers
size of muscle fibers
Match the muscle fiber type with its characteristics.

1. Respond rapidly to nervous system stimulation ______________
2. Fatigue quickly ______________
3. Contain large amounts of myoglobin ______________
4. Break down ATP relatively slowly _____________
5. High glycogen concentration ______________
6. High aerobic capacity ____________
1. Fast-twitch
2. Fast-twitch
3. Slow-twitch
4. Slow-twitch
5. Fast-twitch
6. Slow-twitch
Picking up a heavy box from the floor is best performed with bent legs and a relatively straight back. Simply bending at the waist (and keeping the legs straight) makes it more difficult for the low back muscles to generate a strong contraction, and they may become damaged. Which of the following best explains why the back muscles generate such a weak contraction?

1. They are overstretched, resulting in poor overlap between the thick and thin filaments

2. They have a sarcomere spacing of 2.0 to 2.5 micrometers, which is optimal overlap between myosin and actin for cross-bridge formation.

3. The motor neurons are unable to activate the muscle fibers in this position.

4. The muscle fibers of the deep back muscles are primarily fast-twitch and therefore have already fatigued.
They are overstretched, resulting in poor overlap between the thick and thin filaments
If one action potential from the nervous system arrives at a muscle fiber so soon that the fiber has only partially relaxed from the previous twitch, the most likely result will be __________.

1. fatigue
2. spasm
3. incomplete tetanus
4. complete tetanus
3. incomplete tetanus
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