Communication is vital for any network to function smoothly whether within a singular cell or within a group of cells working together as a system.  In order to maintain homeostasis, a cell, a system, an organism needs to be able to gather information about its internal and external environment and respond appropriately.

This assignment will examine communication at the cellular level and at the systemic level.  We will begin our study with how cells communicate and regulate their internal environment in response to external changes.

We will then examine how the body utilizes such a network of communication to enable a group of cells to work in concert with one another to maintain homeostasis on an organismal level through a study of the nervous and endocrine systems.  Our study of the nervous system will also include the effects of drugs on the body's ability to maintain homeostasis.

PART I:  PRINCIPLES, UNIT 1:  PRINCIPLES OF CELL BIOLOGY:
                                          CELLS AND THEIR ENVIRONMENT

•READ chapter 3:  Cells and their Environment

•3-1  Structure of the Plasma Membrane  "The envelope that makes up the outer surface of a cell is called the plasma membrane.  If you were small enough to stand on the outer surface of a cell, you would float, because most of the cell’s plasma membrane is liquid.  Floating alongside you would be proteins shaped like boulders, while towering overhead like huge trees would be a forest of other proteins.  A plasma membrane is a complex and dynamic structure.  It is the source of a cell’s identity and the site of much of its activity."

**ANSWER:  page 57:  # 1, 3 and 4

•3-2  Moving Materials Into and Out of Cells  "If a cell were simply a bag, with nothing but a phospholipid bilayer for a plasma membrane, its interior would be an inactive place.  Practically nothing would be able to enter or leave the cell.  Sitting inside such a cell would be like sitting inside a room with no windows or doors.  No cell is like that, of course, because every cell has an assortment of proteins extending through its plasma membrane that act as its windows and doors."

**ANSWER:  page 65:  # 1-3 and 6
page 497 # 18

•3-3  How Cells Communicate  "Bringing the ‘groceries’ in and taking the ‘garbage’ out are not the only things that cells do.  Just as in your house you answer the phone and watch television, so the cells of your body communicate with the world outside.  Your cells communicate with each other in order to coordinate the body's growth, development, and other activities."

**ANSWER:  page 68:  # 2
Multiple choice:  # 3, 4 and 10
Short answer:  # 20 and 21
 

EXPERIMENTAL:  Osmosis and the Potato

PART II:  EXPLORATIONS, UNIT 9:  EXPLORING HUMAN BIOLOGY:
    Nervous System

•40-1  Neurons and Nerve Impulses  "Cells in the human body could communicate using only chemical signals, except for one problem:  circulating chemicals is a very slow form of communication.  A quicker means of communication is needed, especially if your brain has an urgent message for the muscles in your leg, such as ‘Contract quickly, a speeding car is headed this way!’  To solve this problem, humans and most other animals have neurons, specialized cells that can quickly transmit messages throughout the body."

**ANSWER:    page 943 #1, 2, 4-7, and define polarization, depolarization and repolarization

•40-2  Architecture of the Nervous System  "Humans, like all other animals except sponges, use a network of nerve cells to gather and integrate information about the body's internal and external environments and to send messages to the body's muscles and glands.  Nerves connect every part of your body to its command-and-control center, the brain and spinal cord.  Your body is run like a submarine:  information about what is happening inside and outside the body flows into the control center, which analyzes the data and issues commands."

**ANSWER:    page 949  #1, 3-6

Vocabulary:  central (brain and spinal cord) and peripheral nervous system (motor and sensory nerves, autonomic system (sympathetic and parasympathetic), reflex, parts of brain (medulla, hypothalamus, cerebellum and cerebrum), psychoactive, depressant and stimulant, enkephalin, neuron (axon, myelin, dendrite, cell body), synapse, and neurotransmitter.

•40-3  The Sense Organs  Reading and Questions as assigned by your teacher

•40-4  Drugs and the Nervous System  "We live in a drug oriented society.  Television commercials and other forms of advertising tell you about pain relievers, antacids, cough syrups and other medications you can buy to help you feel better.  Many drugs can prevent, treat, or cure illnesses that used to be deadly.  However, when drugs are taken for non medical reasons drug abuse can occur.  Few social problems in this country have had a greater impact on people's lives than the spreading abuse of addictive drugs."

**ANSWER:    page 961  #1-7
 

EXPERIMENTAL:  Slides and slide sets of neurons and reflex arc, Reaction sticks and Learning Experiment and value sheets (some may be done next week)

FILMS:  Human Brain, Mind/Brain Two Brains, Mind/Brain Addiction
 
 

PART II:  BIOLOGICAL EXPLORATIONS:  UNIT 9:   HUMAN BIOLOGY
    Hormones and the Endocrine System

•41-1  Hormones (omit sex hormones)  "The tissues and organs of your body carry out a multitude of activities.  Activities…must be coordinated to prevent them from conflicting with one another.  This coordination, plus a smoothly functioning set of organs, is what truly makes an organism alive.  As you learned…the central nervous system coordinates the body's activities.  Fast-acting but short-lived nerve messages are sent by electrical signals that travel along neurons, much as telephone messages travel along wires.  For a longer-lasting effect, the central nervous system signals the release of hormones—chemical messengers that are produced in one place and transported to another by the bloodstream."

**ANSWER:  page 972 #1 and 2

•41-2  How Hormones Work (reading and questions as assigned by your teacher)  "After hormones are produced, they travel through the bloodstream to their target cells, where they cause a change in the activity of the cells.  Hormones cause an effect in a cell by attaching to a receptor protein in one of three ways.  Some hormones enter the cells they affect, while others do not…The location of the receptor proteins for a hormone determines its mode of action.  In any case, the hormone's message must cross a plasma membrane in order to cause a response (see Fig. 41-7).  How does the binding of a hormone to a receptor cause a change in a cell’s activity?  The main way that hormones affect cells is by altering the activity or amounts of certain enzymes, which in turn alters chemical reactions that occur in the cells."

•41-3  The Body's Endocrine Glands  "About a dozen major endocrine glands collectively make up your endocrine system…"  This section shows the glands, their locations, the hormones they make, and what they do.

**ANSWER:   page 985 #1-5.

Vocabulary:  endocrine and exocrine glands, adrenal cortex and medulla, adrenaline, cortisone, diabetes, insulin, pancreas (Islets of Langerhans) endorphin, parathyroid gland and hormone, pituitary, target cells, thyroid and thyroxin, iodine and prostaglandins.
 

EXPERIMENTAL:  Blackworm and drugs investigation

Note:  All quotations are taken from Raven and Johnson

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