8
Bio-Medicine 102

8.1 Human Anatomy and Physiology: An In-depth Look at the Human Endocrine System

If this book were to include a section devoted to each and every human anatomical system (circulatory, muscular, skeletal, nervous, digestive, etc.), its focus might get lost. Thus, the endocrine system has been selected as the most sensible human anatomical system to be discussed in depth. After all, the endocrine glands produce powerful chemicals called, hormones.

So, in this section, we will concentrate on the endocrine system, which consists of “ductless” glands, each of which secretes different types of hormones directly transported by the bloodstream (not transported by nerve impulses!) to act on specific target organs and distant tissues to maintain homeostasis.

Diseases of the endocrine system can result from the hyper- or hypo-secretion of hormones or from the inability of target organs or tissues to respond to hormones effectively.

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Figure 8.1 Endocrine system. (© stockshoppe – fotolia.com.)

8.1.1 Mr. H's Tip: Prefixes with Greek or Latin Language Roots, which are Heavily Used in Chemistry, Medicine and Other Sciences

  • hyper- versus hypo-
    • hyper-, meaning excessive, too much; as in an hyperactive; or on top of, above
    • hypo-, meaning deficient, too little, or below, underneath; as in hypothalamus
  • endo- versus exo-
    • endo- internal, inside as in endocrine gland or endoskeleton (i.e., as in vertebrate animals like mammals)
    • exo- external, outside as in exocrine gland or exoskeletons (i.e., as in invertebrates like arthropods).

Use of meta-, para-, ortho- in the medical, chemical and science fields.

para, ortho, meta, prefixes are used in organic chemistry to designate the position of two identical or different substituents relative to each other in a benzene (Benzol) ring. For example:

  • meta (m) – compounds are located in the 1,3 positions
  • ortho (o) – compounds occupy the 1,2 positions
  • para (p) – compounds are in the 1,4 positions.

However, these prefixes are also used in other science fields, including medicine:

  • para-, meaning “near-by”; as in parathyroid
  • ortho-, meaning “straight”; as in orthodontist, orthopedist
  • meta-, meaning “changed”; as in metamorphic rocks

8.1.2 Comparing Endocrine (Ductless) Gland vs. Exocrine (Duct) Gland

Before defining the two terms, duct versus ductless glands, we need to understand what a secretion is, which is defined by most medical dictionaries as, “a useful substance produced by a gland or cell. In addition to the enzymes and hormones that facilitate and regulate complex biochemical processes, body tissues also secrete a variety of substances that provide lubrication and moisture. Within an individual cell, the Golgi apparatus (further discussed in Chapter 17) and its associated secretory granules are thought to be the structures responsible for the production and release of secretory substances in cells.”

  1. 1. Endocrine gland (ductless): no tubes exist and each gland produces specific hormones that go directly into the bloodstream or surrounding tissue.
  2. 2. Exocrine gland (duct): possesses tubes through which it secretes its products.

Examples of exocrine glands:

  • Sweat glands (sweat production for cooling the body down)
  • salivary glands (ptyalin production for starch digestion)
  • mammary glands (milk production in females to nurture their young).

Examples of exocrine gland secretions:

  • bile, a fluid produced by the liver, stored in the gall bladder and secreted into the intestinal tract to help digest fat molecules
  • tears from the eyes, which can come from emotional stress, but also tend to cleanse the eye
  • mucus, a viscous, slippery substance that consists chiefly of mucin, water, cells, and inorganic salts and is secreted as a protective lubricant coating by cells and glands of the mucous membranes.

8.1.3 The Endocrine System

Hormones secreted by each gland and diseases associated with hyper-/hypo hormone production.

Endocrine gland Hormones produced Endocrine gland's function
Pituitary (Hypophyse) Anterior lobe Controls bone and general body growth
Growth hormone
  • Hyper: gigantism
  • Hypo: dwarfism
TSH (thyroid stimulating hormone) Stimulates formation of thyroxin hormone and growth of the thyroid gland
ACTH (adrenal-cortex stimulating hormone)
  • stimulates adrenal-cortex to produce corticosteroids (mineral and gluco-corticoids)
  • cortisol (anti-inflammatory)
  • androgens
FSH (follicle stimulating hormone)
  • female: stimulates maturation of ovarian follicles in ovary
  • male: stimulates maturation of seminiferous tubules
LTH (luteinizing hormone)
  • female: Stimulates ovulation and formation of corpus luteum
  • male: Stimulates testosterone synthesis from Leydig cells (interstitial cells)
Prolactin Production of milk in breast
Posterior lobe
Oxytocin Stimulates uterine contraction and breast contraction for milk release
Vasopressin the anti-diuretic hormone (water re-absorption)
Pineal Melatonin Hormone derived from serotonin, which regulates the sleeping cycle
Thyroid Thyroxin Controls one's metabolic rate
Hyper-
  • metabolism ↑
  • potential for Goiter, where the thyroid enlarges due to insufficient amounts (Mangel\ an) of Iodine (Jod), which is essential for proper thyroxin production
  • possible link with Attention Deficit Disorder (ADD)
  • bulging eyes due to accumulation of fluid behind the eye
Hypo-
  • metabolism ↓
  • weight gain (Gewichtszunahme)
  • lethargic (träge, lethargisch)
  • Graves Disease and Cretinism associated to poor thyroxin production
Calcitonin Ca2+ uptake in bones
Parathyroid ( para-, meaning “nearby”, in this case, the thyroid) Parathormone Associated with proper muscle and bone growth, regulate Ca2+ and phosphate in body
Thymus The thymus “educates” the T-lymphocytes cells, which are critical for the immune system Associated with immunology, and as a child develops → teenage, Thymus shrinks in size (atrophy)
PancreasThe Isles of Langerhans (Langerhans-Inseln)
  • Beta cells: Insulin
 Increases cell use of glucose (sugar) and glycogen (sugar, stored as animal starch in liver) Malfunction: Diabetes
  • Alpha cells: Glucagon
 Increases the formation of glucose from liver
Adrenal; The “fright, fight, flight” gland! Cortex (outer):
  • Glucocorticoids; cortisone, cortisol
  • Aldosterone
  • Regulates carbohydrate, fat, and protein usage
  • Regulates body fluids (NaCl and H2O) balance
Medulla (inner):
  • Adrenalin
  • Noradrenalin
 Prepares one for “fright, fight, flight” Constrict blood vessels → increase BP (blood pressure)
Ovaries
  • Estrogen
  • Progesterone
 Stimulates maturation of female reproductive organs, development of secondary sex characteristics (body hair, physical body development, etc.)
Testes Testosterone Stimulates maturation of male reproductive organs, development of secondary sex characteristics (body hair, physical body development, etc.)

8.2 Laboratory Animals

8.2.1 The Animal Kingdom: Gender, Grouping, and Offspring Names

Many in the bio-medical, life science fields (veterinarians, biological testing or pharma lab personnel, medical staff, etc.) or industry (biocide development) find themselves working with animals, but are not sure of the male, female, baby, or grouping names.
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Figure 8.2 Pioneer 11, which was launched in 1973 by NASA (Cape Kennedy, Florida, USA) had this plaque mounted on it. The satellite traveled on an ambitious route toward Jupiter, with a fly-by the planet Saturn and then toward interstellar space. Since 1995, and at such great distances, communication with Pioneer 11 has been lost; however, if Pioneer 11 meets “ET” the golden plaque with its recording about mankind and the human (male and female) figures on the plaque will help “ET” identify that the satellite came from our planet Earth, which is the third planet from our Sun in our solar system. (Copyright NASA.)

To get familiar with the pattern of this section, let's use humans as the first example:

Group name (Gruppenbezeichnung) Masculine (männlich) Feminine (weiblich) Offspring (Infant) name (Bezeichnung des Jungen)
Human (Mensch)
  • People (Volk, Leute)
  • Population (Einwohnerschaft)
  • Community(Gemeinschaft)
 Mans. (Mann) Womans.(Frau)
  • Baby (Baby)
  • Girl (Mädchen)
  • Boy (Junge)
Animal Group name Masculine Feminine Infant name
Alligator, crocodile (Alligator, Krokodil) Bask, congregation Bull Cow Hatchling
Baboonspl. (Paviane) Troop Male Female Baby, infant
Chicken (Huhn) Brood, clutch Rooster Hen Chick
Cow (Kuh) Herd Bull Heifer Calf
Deer (Hirsch) Herd Buck, stag Doe Calf, fawn
Dog (Hund) Pack Dog, stud Bitch Pup, puppy, whelp
Elephant (Elefant) Herd Bull Cow Calf
Fish (Fisch) School Male Female Fry, hatchling
Frog (Frosch) Colony N.A. N.A. Tadpole
Giraffe (Giraffe) Herd Bull Cow Calf
Gooses. (Gans) Gackle of geese Gander Dame Gosling
Geesepl. (Gänse)
Guinea pig (Meerschweinchen) Herd Boar Sow Pup
Hippopotamus (Flusspferd) Herd Bull Cow Calf
Horse (Pferd) Herd Stallion Mare Foal; colt (m)/filly (f)
Insects (Insekta):
  • ants (Ameisen)
 Army, colony Drone Queen Larva, pupa
  • bees (Bienen)
 Hive, swarm, colony Drone Queen Larva, pupa
  • fly (Fliege)
 Swarm, colony Drone Queen Larva, pupa
Lion (Löwe) Pride Lion Lioness Cub, whelp
Locustspl (Heuschrecke) Plague, swarm Male Female Larva, pupa
Mouses. (Maus) Horde, family Buck Doe Pup
Micepl (Mäuse)
Pig (Schwein) Herd Boar Sow Piglet
Rat (Ratte) Colony or horde Buck Doe Pup
Seal (Seehund) Herd Bull Cow Pup
Sheep (Schaf) Flock, herd Buck Ewe Lamb
Tiger (Tiger) Pride, family Tiger Tigress Cub

To be discussed in Chapter 17, bacteriapl., which are anucleated microscopic organisms are not animals, and thus not included here.

8.2.2 QUIZ YOURSELF – The Animal Kingdom: Gender, Grouping, and Offspring names

So what have you learned from the charts, vocabulary stated above and previous chapter's topics? Let's find out! Please answer the following multiple choice questions:

  1. 1. Concerning bacteria, which statement is correct?
    1. a. They are animals, which reproduce sexually
    2. b. They are plants, which reproduce sexually
    3. c. Bacteria are macroscopic organisms, with cells having well-defined nuclear membranes
    4. d. None of these
  2. 2. Which animals travel in herds?
    1. a. Elephants, fish, and alligators
    2. b. Elephants, cows, and deer
    3. c. Locusts, ants, and bees
    4. d. Alligators, tigers, and mice
  3. 3. Which animal's female gender is known as a “hen”?
    1. a. Chicken
    2. b. Guinea pig
    3. c. Dog
    4. d. Pig
  4. 4. Which of these animals is matched properly with its male gender name?
    1. a. Pig – sow
    2. b. Cow – heifer
    3. c. Baboon – troop
    4. d. Horse – stallion
  5. 5. Which of these animals is matched properly with its baby's biological name?
    1. a. Bee and locust – larva, pupa
    2. b. Cow and deer – calf
    3. c. Dog and seal – pup
    4. d. All of these
  6. 6. Which of the following organisms would certainly require a microscope to view its entire features?
    1. a. Staphylococcus, which is a round-shaped bacteria
    2. b. Anthrax, which is caused by a bacillus bacterial infection
    3. c. Spiral-shaped Helicobacteria, which can cause gastric (stomach, digestive) problems for humans
    4. d. All of these
  7. 7. Which of the following organisms would not require dissection to observe its internal body tissues or organs?
    1. a. Mice
    2. b. Dogs
    3. c. Baboons
    4. d. Streptococcus

8.2.3 Working with Laboratory Animals

Comparing a Frog (Figure 8.4) with a Mouse (Figure 8.3): Observing these two photos, are these animals vertebrates or invertebrates? Why? Which is a Mammal? Amphibian?

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Figure 8.3 Mouse. (© Dimco – fotolia.com.)

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Figure 8.4 Frog. (© Matteo Gabrieli – fotolia.com.)

Both the frog and rat are vertebrates (animals with backbones), but…

  • Frog is an amphibian.
  • Mouse is a mammal.

For companies producing or selling cosmetics within in the EU, an animal test ban regulation is now in full effect. However, in the pharmaceutical and medical fields, testing with laboratory animals still exists. This manual is not written for the sake of debating this issue, but to help those reading it with the vocabulary related to working with animals in the laboratory. So, for those who must perform experiments on certain animals, let's look at some sector keywords below.

8.2.4 Dissection and its Instrumentation

Commonly used Anatomical terms of Human-/Animal Body Locations

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Figure 8.5 Dissection instruments. (© leremy – fotolia.com.)

Anatomical position Definition Deutsche Bezeichnung
Anterior ≠ posterior Front (nose) ≠ end (tail) Anterior ≠ posterior
Cranial ≠ caudal Toward (twd.) brain ≠ twd. bottom (anus) Kranial kopfwärts ≠ kaudal, schwanzwärts
External or superficial (as in a superficial wound, meaning, “on the skin's surface”) ≠ internal (deep) Twd. the body's surface ≠ away from the body's surface äußere ≠ innere
Lateral Twd. the body's side Zur Seite hin, lateral
Medial Twd. the body's midline or mid-section Zur Mitte hin, medial
Proximal (as in, proximity) ≠ distal twd. body's main mass ≠ away from body's main mass Proximal, (näher zur Körpermitte, rumpfwärts gelegen) ≠ distal, [vom Körperstamm nach außen gerichtet oder von der Körpermitte weg gerichtet]
Superior ≠ inferior Toward head ≠ twd. Feet Oben ≠ unten
Ventral ≠ or dorsal N.A. Vorn ≠ hinten
Visceral ≠ parietal Related to body's internal organs ≠ Related to body's walls Viszeral ≠ parietal