Introduction

Chapter 1. Chapter 25: Overview of Physiology

Interactive Study Guide
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Welcome to the Interactive Study Guide for Chapter 25: Overview of Physiology! This Study Guide will help you master your understanding of the chapter's Driving Questions, using interactive Infographics and activities, as well as targeted assessment questions. Click "Next" to get started, or select a Driving Question from the drop-down menu to the right.

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DRIVING QUESTIONS

  • How are the bodies of living organisms organized?
  • How do humans and other organisms regulate body temperature?
  • What physiological systems are regulated by homeostatic feedback loops?

Driving Question 1

How are the bodies of living organisms organized?

Why should you care?

Your anatomy is made up of different kinds of cells that form tissues, which form organs, which form organ systems, which form your body. Understanding the organization of your body and the parts involved is a crucial part of understanding your health.

What should you know?

To fully answer this Driving Question, you should be able to:

  1. Describe the relations among cells, tissues, organs, and organ systems.
  2. Describe examples of various types of cells and tissues.

Infographic Focus

The Infographic most pertinent to the Driving Question is 25.1.

Test Your Vocabulary

Choose the correct term for each of the following definitions:

Term Definition
A structure made up of various tissue types working together to carry out a common function.
An organized collection of a single cell type working to carry out a specific function.
The study of the physical structures that make up an organism.
The study of the way a living organism’s physical parts function.
A set of cooperating organs.
Table
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Describe the relations among cells, tissues, organs, and organ systems.

1.

Create an anatomical organization scheme by filling in the table with an example of:

  • a cell type.
  • a tissue that contains cells of this type.
  • an organ that contains this tissue type.
  • an organ system that contains this organ.
  • an organism that contains this organ system.

Then explain how each anatomical structure is different from its neighbor in the organizational scheme.

Structure Example How is each anatomical structure different from the one below it?
Cell type

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Tissue that contains the cell

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Organ that contains the tissue

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Organ system that contains the organ

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Organism that contains the organ system

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Structure Example How is each anatomical structure different from the one below it?
Cell type Cone A cell is the smallest unit of life in the body. It cannot be broken down into its components and still maintain life.
Tissue that contains the cell Retina A tissue is a collection of one cell type.
Organ that contains the tissue Eye An organ is a collection of tissue types working together.
Organ system that contains the organ Nervous system Organ systems are composed of various organs, all working together to perform a vital task. One organ system alone, however, cannot maintain life.
Organism that contains the organ system Rabbit An organism is composed of all organ systems working together to maintain life.

Incorrect

Describe the four basic types of cells and tissues generally found in animals.

2.

List the four basic cell types of animals and the names of the corresponding tissues they make up.

Cell Type Corresponding Tissue Type
2

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Review Questions

5.

Different _____ working together for a common function make up a(n) _____.

A.
B.
C.
D.
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Driving Question 2

How do humans and other organisms regulate body temperature?

Why should you care?

Your home has features like thermostats, air conditioners, pressure regulators, water heaters, and insulation that all work to maintain constant conditions in it. Just like a house, your body maintains relatively constant conditions in several ways. Many diseases, for example diabetes, result from faulty regulation of conditions in the body. Knowing about homeostasis—how the body maintains a constant state—can help us understand how to take better care of our own health.

Your body uses several processes to maintain a constant body temperature. When the outside temperature is extremely cold, the body works to maintain a constant internal temperature by conserving the heat it has and generating additional heat. When the outside temperature is extremely hot, the body also works to maintain a constant internal temperature by expelling heat and sweating. Learning about thermoregulation will give you insight into how organ systems in your body work cooperatively to maintain homeostasis.

A feedback loop is a cyclic pathway of sensing and effecting that works to regulate something in the body. When that something is body temperature, the sensing is done by thermosensors, special nerves in outer layers of the skin, and the effecting is done by muscles and blood vessels. Learning about how body temperature is regulated could help you avoid behaviors that will lead to either hypothermia or overheating. For example, alcohol is often suggested as a means to warm up in cold weather, but it actually works as a vasodilator, bringing more blood to the skin, where it initially makes a person feel warmer but will quickly lead the blood to cool as it gives off its heat.

What should you know?

To fully answer this Driving Question, you should be able to:

  1. List the conditions that the human body keeps relatively constant to maintain homeostasis.
  2. Explain the various processes involved in maintaining a constant body temperature in response to cold and heat.
  3. Identify the components and processes involved in the feedback loop that is responsible for thermoregulation in humans.

Infographic Focus

The Infographics most pertinent to the Driving Question are 25.2 to 25.4.

Test Your Vocabulary

Choose the correct term for each of the following definitions:

Term Definition
A pathway that includes input from a sensor, a response via an effector, and detection of the response by the sensor.
The maintenance of a relatively stable internal environment even when the external environment changes.
The reduction in diameter of blood vessels, which helps to retain heat.
A cell that detects specific sensory input, such as temperature, pressure, or solute concentration.
The maintenance of a relatively stable internal body temperature.
A cell or tissue that acts to exert a response on the basis of information relayed from a sensor.
A master coordinator region of the brain responsible for a variety of physiological functions.
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List the conditions that the human body keeps relatively constant to maintain homeostasis.

7.

Without looking at Infographic 25.2, list some of the conditions in the human body that are kept relatively constant in healthy people. Then refer to Infographic 25.2 and fill in any conditions you might have missed.

Why is it important for the body to regulate these conditions? Fill in your answers next to the conditions.

Condition Maintained at a Constant Level in the Body Reason It Is Important to Maintain This Condition Constant

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Condition Maintained at a Constant Level in the Body Reason It Is Important to Maintain This Condition Constant
Body temperature Proteins (including enzymes) can function only in a small window of optimal temperature.
Blood pH Proteins (including enzymes) can function only in a small window of optimal pH.
Blood Pressure If your blood pressure is too low, not enough blood will get to your brain and organs. If your blood pressure is too high, you may rupture a vein or artery.
Incorrect.

Explain the various processes involved in maintaining a constant body temperature in humans.

8.

Consider shivering and vasoconstriction. Which one conserves heat, and which one generates heat? How do they accomplish this?
Shivering generates heat because to contract, the muscles must carry out cellular respiration, releasing energy as heat. Vasoconstriction conserves heat; it reduces the diameter of surface blood vessels and redirects blood to the body core, which controls the temperature of the vital organs. This movement of blood toward the body core also decreases the amount of heat loss through the skin.

Identify the components and processes involved in the feedback loop that is responsible for thermoregulation in humans.

10.

Place the listed events in the order in which they would occur for the given scenario.

You are camping in northern Minnesota at the end of October, when temperatures can dip below freezing (32°F) during the night. Your campfire goes out while you are sleeping and you wake up shivering but soon feel warm again. Place the statements in the order that they likely occurred.

Hypothalamus detects temperature change and receives signal from thermosensors
Thermosensors in the skin detect a change
Body maintains appropriate temperature
Vasoconstriction occurs in limbs
Muscles contract involuntarily (shivering)
Hypothalamus detects temperature change and no longer receives signals from thermosensors.
Temperature drops and body becomes cold
Internal body temperature rises
Hypothalamus sends signals to effectors
Thermosensors in the skin detect a change again
Table
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Review Questions

13.

Which of the following is NOT maintained by homeostasis in humans?

A.
B.
C.
D.
E.
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Driving Question 3

What physiological systems are regulated by homeostatic feedback loops?

Why should you care?

Feedback loops in your body continually survey and measure various elements inside and outside of your body to maintain optimal functioning of your organ systems and therefore your body as a whole. Maintaining homeostasis is important, as even a slight tip in that balance in either direction could have dire consequences for your overall health. Two examples of homeostatic feedback loops are the loop that maintains blood glucose levels and the loop that regulates the pressure, solute concentration, and water concentration of your blood.

What should you know?

To fully answer this Driving Question, you should be able to:

  1. Describe the components and processes in the feedback loop that is responsible for blood glucose level regulation in humans.
  2. Describe the components and processes in the feedback loop that is responsible for osmoregulation in humans.
  3. Explain what happens when glucose levels and osmolarity are not well regulated.

Infographic Focus

The Infographics most pertinent to the Driving Question are 25.5 and 25.6.

Test Your Vocabulary

Choose the correct term for each of the following definitions:

Term Definition
An energy-storing carbohydrate found in liver and muscle.
The organs that sense and respond to information, including the brain, spinal cord, and nerves.
A hormone secreted by the pancreas that causes a decrease in blood sugar.
The maintenance of relatively stable volume, pressure, and solute concentration of bodily fluids, especially blood.
A chemical signaling molecule that is released by a cell or gland and travels through the bloodstream to exert an effect on target cells.
The hormone-secreting glands and organs with hormone-secreting cells.
A hormone produced by the pancreas that causes an increase in blood sugar.
An organ involved in osmoregulation, filtration of blood to remove wastes, and production of several important hormones.
An endocrine gland in the brain that secretes many important hormones.
The concentration of dissolved solutes in blood and other bodily fluids.
An organ that secretes the hormones insulin and glucagon and digestive enzymes.
A drop of body temperature below 35°C (95°F), which causes enzyme malfunction and eventually death.
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Describe the components and processes involved in the feedback loop that is responsible for blood glucose level regulation in humans.

16.

Examine Infographic 25.5 and answer the following questions.

What two steps in the blood glucose level feedback loop result in a rise of blood glucose levels?
1. Pancreas releases glucagon into the blood.
2. Liver and muscle cells break down stored glycogen into glucose.

Describe the components and processes involved in the feedback loop that is responsible for osmolarity regulation in humans.

22.

Describe what happens when your body is dehydrated.
During dehydration, osmolarity increases, and your body will take steps to retain water. Receptors in your blood vessels detect low blood pressure and a high concentration of solutes. This sends a signal to the hypothalamus, which will not only induce thirst but will also increase the release of antidiabetic hormone (ADH) into the blood. ADH signals the kidneys to retain more water (by excreting less in the urine), which will cause the water to be reabsorbed into the bloodstream. This in turn will dilute the solutes and decrease the osmolarity.

Explain what happens when glucose levels and osmolarity are not well regulated.

24.

Type 1 diabetes is inability of the body to make insulin. How would this affect the regulation of blood glucose levels?
Insulin is responsible for signaling the body cells, liver, and muscle cells to take in glucose and either use it as energy or store it as glycogen. Without insulin the body cannot use glucose as fuel or store it, so the blood glucose level remains high.

Review Questions

26.

The release of ____________ by the pancreas into the blood would be followed by ____________ in blood-glucose level.

A.
B.
C.
D.
E.
2
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