UNIT 6: PHYSIOLOGYChapter 22: Homeostasis, Reproduction, and Development
1.
Seeking Stability
2.
All in the Timing
3.
Spotlight on Sperm
4.
Driven by Hormones
5.
“Do It for Denmark”
6.
Review
Reviewing the Science
• Cells that work in an integrated manner to perform a common set of functions constitute a tissue. Four main types of tissues are
found in vertebrates: epithelial, connective, muscle, and nervous. An organ is made up of more than one tissue type and forms a
functional unit with a distinctive function, shape, and location in the body. An organ system is composed of two or more organs
that work in a closely coordinated manner to perform a distinct set of functions.
• Homeostasis is the process of monitoring the internal environment of an organism. Homeostatic pathways have two basic
features: sensors that monitor the internal environment, and regulatory processes that attempt to restore the normal internal state
when deviations from optimal conditions are detected.
• Many homeostatic pathways are controlled by feedback loops. In negative feedback loops, the results of a process cause that
process to slow down or stop. In positive feedback loops, the results of a process cause it to speed up.
• Sexual reproduction involves the organs of the reproductive system and the union of male and female gametes (sperm and
eggs). Most animals produce offspring in this way, although some can individually produce genetically identical offspring via
asexual reproduction.
• Oogenesis and spermatogenesis are the production of eggs and sperm, respectively. Fertilization fuses the haploid sperm and
haploid egg to produce a diploid zygote. Males produce sperm in testes, and females produce eggs in ovaries.
• Approximately monthly, one egg released from a woman’s ovary moves into the oviduct, where it can be fertilized. During
sexual intercourse, the man’s penis releases into the woman’s vagina nearly 300 million sperm, only one of which can fertilize
the egg.
• During the first trimester of human development in the uterus, cells of the embryo rapidly differentiate into the various organs
and structures present at birth. From the ninth week of development on, the developing human is called a fetus. During the
second and third trimesters, the fetus grows rapidly.
• Childbirth occurs in stages. The hormone oxytocin signals uterine muscles to contract. The contractions become stronger as
positive feedback increases the amount of oxytocin produced.
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NAME:
DUE DATE: April 11, 2022
MAXIMUM POINTS AVAILABLE: 40
No E-mail or photography submission will be accepted. Typed your answers below the questions………
PART – I:
1 point/question
1. Which tissue type is the primary component of skin?
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2. What level of biological organization comes just above the tissue level (for example, what
level is immediately above the tissue level in complexity)?
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3. Which of the following is a main benefit of multicellularity?
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4. Give three major functions of skin
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5. Which organ system is responsible for controlling body activities via chemical signals that
travel through the bloodstream?
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6. ____ , _____, and ____ are all part of the integumentary system.
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7. Homeostasis is defined as:
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8. Your body sweats in hot weather but stops sweating when you enter an air-conditioned
building. The cessation of sweating as the body becomes cooler is an example of:
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9. The process of regulating internal salt and water concentrations is known as:
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10. Which conditions is most likely to directly cause hypothermia?
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11. A woman begins to go into labor and her uterus contracts. The contracting uterus causes
the release of the hormones oxytocin and prostaglandin. These hormones go on to intensify the
strength of the contractions, which then go on to cause a further release of these two
hormones. Which regulatory systems best describes this phenomenon?
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12. When an animal enters into hibernation, its:
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13. What is the most common type of feedback information used in the regulatory systems of
homeostasis?
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14. What is the typical order of events to produce an embryo?
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15. Sea stars (also called starfish) sometimes break off one of their “arms,” which then develops
into a separate sea star. Is this an example of asexual or sexual reproduction? Sea stars (also
called starfish) sometimes break off one of their “arms,” which then develops into a separate
sea star. Is this an example of asexual or sexual reproduction?
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16. Place these terms in the correct order of development: embryo, fetus, infant, zygote.
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17: In what trimester is the fetus most likely to survive outside its mother’s body?
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18.: The first trimester is the most sensitive time for exposure to mutagens. Why might that be?
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19: What is the role of estradiol in childbirth?
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20: Explain how the involvement of hormones in childbirth is an example of a positive feedback
loop.
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21: Which organ system defends the body from infectious diseases such as the common cold or
flu?
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22: Which organ systems transport oxygen to cells?
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23: Which organ systems regulate the activities of the other organ systems?
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24: Which tissue types does the hand contain?
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25: Which organ system is involved as a temperature sensor? (See Figure 22.4 for an overview
of organ systems.)
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26. How homeostasis is regulated?
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27. Which two organ systems together transport oxygen to cells
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28. Which hormone is involved in producing the uterine lining?
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29. What is corpus luteum?
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30. How much time elapses between the appearance of a precursor cell and the formation of
an egg?
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PART II:
0.5 point/ items
1 Select the correct terms:
Homeostasis maintains a constant internal state through (homeopathic / homeostatic) pathways
that trigger regulatory processes when there is movement away from the body’s (set point /
initiator). For example, body temperature homeostasis is maintained through a (negative /
positive) feedback loop—a process known as (thermoregulation / osmoregulation).
2 Place the following events of the human menstrual cycle, beginning with the final day of
bleeding, in the correct order by numbering them from 1 to 5.
___a.
0.5 point/matching
The corpus luteum produces progesterone for about 14 days.
____b. Follicle-stimulating hormone (FSH) stimulates the growth of egg follicles.
___c.
The egg is released from the follicle (now corpus luteum).
___d.
The uterine lining sloughs off (menstruation occurs) with decreased progesterone.
____e. Estrogen levels increase and trigger luteinizing hormone (LH).
3. Link each term with the correct definition.
Spermatogenesis
1. Cells from only one parent produce offspring.
Oogenesis
1 point/link
2. The process of producing sperm.
Sexual Reproduction 3. The process of producing eggs (ova).
Asexual Reproduction 4. Gametes from two parents combine to produce offspring.
MULTIPLE CHOICES:
0.5 point / choice
1. The most immediate reason(s) why homeostasis is important in the human body is that:
a) cells cannot divide properly when the environment changes, preventing growth.
b) the DNA in a cell’s nucleus is damaged easily by environmental change.
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c) enzymes inside and outside cells cease to perform essential metabolic functions if the body is
out of balance.
d) the rate of transport across membranes is altered by changes in a cell’s environment.
e) Both the third and fourth choices are correct.
2. A hiker climbing Mount Washington in New Hampshire encounters fog and rainy conditions,
and her clothes become completely soaked. Within a couple hours, she is stumbling and has
trouble understanding which way to go at a fork in the trail. What is the likely condition from
which this hiker is suffering?
a) hyperthermia, because she had on too many layers of clothing so she could not cool off by
sweating
b) hypothermia, because she lost too much body heat to the environment
c) homeostasis, because her body shut off blood to her brain
d) hypoxia (low blood oxygen), because the higher altitudes on Mt. Washington carry less
oxygen in the air
e) hypoglycemia (low blood sugar), because she wasn’t eating enough carbohydrates compared
to what her body was using
3. Which of the following explains why complex multicellular organisms face a major challenge
in maintaining homeostasis?
a) Most of the body cells are not in direct contact with the external environment.
b) There are more chemical reactions per cell that require energy and nutrients.
c) Most of the body cells are protected from harsh or changing environmental conditions.
d) Nutrients and waste materials enter or leave the cells too quickly.
e) There is less extracellular fluid from which to gather nutrients.
4. If the “set point” for a physiological variable is a relatively high value:
a) negative feedback will tend to lower the set point.
b) there is no need for a sensor for that variable.
c) the organism with this high set point is considered a conformer for that variable.
d) positive feedback will tend to increase the set point.
e) the body will work to maintain the high value.
5. What animal body structures are mainly involved in osmoregulation?
a) digestive tract
b) bladder
c) kidneys
d) Malpighian tubules
e) Both the third and fourth choices are true.
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