Threesology Research Journal
Biological/Physiological 3s
page 11

(The Study of Threes)

This page is a companion to the following links:

There are three types of plague:

  1. Bubonic, which infects the lymph nodes.
  2. Pneumonic, which infects the lungs.
  3. Septicemic, which infects the blood.

3 distinctions of vertebrates with respect to limbs (does not include mutations nor lost limbs):

Some vertebrates lack both pairs of limbs...

  • Caecilians (apodans)
  • Most snakes
  • Snake-like lizards

Some vertebrates have forelimbs only:

  • Manatees & dugongs
  • Dolphins
  • --- Cetaceans ---

    (Whales- vestigial elements may be embedded in body wall)

  • Sirens (salamander)

Some vertebrates have both pairs of limbs:

  • Humans, Gorillas, Chimpanzees, etc...
  • Cows, Pigs, Horses, Sheep, etc...
  • Dogs, Cats, Weasels, Skunks, etc...

--- Comparative Vertebrate Anatomy ---

Three common autoimmune diseases have an unexpected genetic link:

  1. Psoriasis, (affects 2 percent of Americans.)
  2. Rheumatoid arthritis, (affects up to 1 percent of Americans.)
  3. Systemic lupus erythematosus, (which attacks the joints and can cause severe inflammation, affects one-twentieth of 1 percent of Americans.)

The link among the three diseases involves a protein that helps the thymus gland train cells of the immune system.

--- NY Times: Science ---

Three types of Influenza viruses:

  1. Type A infects a variety of birds and mammals. (Causes epidemics)
    • Two proteins distinguish strain A subtypes: 15 variants of hemagglutinin (H), and nine of neuraminidase (N).

  2. Type B infects only humans. (Causes epidemics)
  3. Type C infects only humans. (Less severe)

A flu vaccine includes B and the most common A subtypes, H1N1 and H3N2; this year's (2003/2004) is:

  1. H1N1 (Caledonia)
  2. H3N2 (Panama)
  3. Strain B (Hong Kong).

Flu viruses change in two basic ways. Antigenic shift is a sudden alteration of a hemagglutinin or neuraminidase; antigenic drift is the backdrop of continual mutation.

  1. Strain A shifts and drifts.
  2. Strain B only drifts.
  3. Strain C only drifts.

Compiled by Ricki Lewis

The Scientist: Devious and Deadly: Influenza through the ages

3 types of Bacterial toxins:

  1. Exotoxins
  2. Endotoxins
  3. Non-Protein Toxins

3 areas used for calculating percentage of body fat by using a set of callipers to measure the thickness of skin folds:

  1. Arm- (bicep and tricep)
  2. Subscapula (just under the shoulder-blade)
  3. Suprailiac (on the front corner of the hip)

3 components of the eye can fully account for the Circadian light responses and pupillary responses:

  1. The melanopsin gene
  2. The rods
  3. The cones

--- The Scientist: Melanopsin Lights the Way ---

3 classes of Annelids:

  1. Class Polychoeta- (meaning "many hairs") includes marine worms, such as sandworms and tubeworms.
  2. Class Oligochaeta- includes the earthworm and some freshwater worms.
  3. Class Hirudinea- comprises the leeches.

3 feeding characteristics of insects: Chewing - Sucking - Lapping.

Three primary brain networks that evolved to direct mammalian reproduction:

  1. The sex drive evolved to motivate individuals to seek sex with any appropriate partner.

  2. Attraction, the mammalian precursor of romantic love, evolved to enable individuals to pursue preferred mating partners, thereby conserving courtship time and energy.

  3. The brain circuitry for male-female attachment evolved to enable individuals to remain with a mate long enough to complete species-specific parenting duties.

--- BBC News: How the brain reacts to Romance ---

Your Questions, Comments or Additional Information are welcomed:

Herb O. Buckland