Having learned about the chemicals and biochemicals of life, we proceed to higher levels of organization

cells > tissues > organs > systems.

Cells

Here's info on cells. Remember from Module 1 that bacteria are "prokaryotes," have no nucleus, and are in a different kingdom than "eukaryotes," that have a nucleus. Much toxicity testing is done, however, with bacteria. Go to:

https://www.khanacademy.org/science/biology/structure-of-a-cell/prokaryotic-and-eukaryotic-cells/v/cell-size

You should skip the first video on cell size, but on the index on the left, look at the other six learning items and two practice items.

Here is a more graphic review,

Cells from NIH Note the first two pages are very brief. The Cell Structure and Cell Function are brief, but have useful information.

You're now an expert on cells.

Tissue

Cells are organized in tissues. There are four tissue types: Epithelial, Connective, Muscle, and Nerve. Read about the four types. (skip membranes)

Tissues

Organs and Organ Systems

• Skeletal
  • Only read the first two pages, you can glance at the rest.
• Muscular
  • Only read the first three pages, you can glance at the rest.
• Nervous
  • Read the section, but skim the anatomy and focus on the function. We'll cover more in the section on toxicity related to the nervous system.
• Endocrine
  • Only read the first three pages, but glance at the rest.
• Cardiovascular
  • Read first two pages, skip the heart anatomy, read blood but skip blood pressure, read capillaries and skip to fetal at the end.
• Lymphatic
  • Read first two pages, glance at the rest
• Respiratory
  • You need only glance at all this, since we go over it in pulmonary toxicity, but spend a moment or two on the section: Bronchi, Bronchial Tree, & Lungs
• Digestive
  • Glance at all this. We'll go over liver in some depth, since that is primary organ for biotransformation of xenobiotics.
• Urinary
  • Glance at all this, but look more carefully at the first page of kidney. We'll go over the kidney in more detail later.
• Reproductive
  • Just glance at all this. Again, we go over what we need in more detail later. Here is a short video that would do as well as the NIH site of reproduction.

A little on the autonomic nervous system: The central nervous system (CNS) is the brain and spinal cord. The CNS is connected to peripheral nervous system, which has two parts, the somatic nervous system that wires up the skeletal muscles and senses, and the autonomic nervous system that hooks up the smooth muscle and glands. The visceral organs are controlled by smooth muscle that operates them, for example the muscles that move the gut contents. The blood supply is controlled by smooth muscles in the arteries and arterioles. The autonomic system has two divisions, the sympathetic and parasympathetic systems. The sympathetic controls the fight or flight response and the parasympathetic calms you back down again, after you have fought or fled.

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Module 2 Index