Human Epithelia

Simple Squamous Epithelium ^

Characteristics: Single layer of flattened cells with disc-shaped nuclei and sparse cytoplasm.

Examples: Present in the kidney glomeruli, lining of heart, blood vessels, lymphatic vessels, and serosae.

Simple Cuboidal Epithelium ^
Characteristics: single layer of cube like cells with large, spherical central nuclei.
Examples: Present in kidney tubules, ducts and secretory portions of small glands, and ovary surface.

Simple Columnar Epithelium ^
Characteristics: Single layer of tall cells with oval nuclei; many contain cilia
Examples: Small bronchi, uterine tubes, and some regions of the uterus

Pseudostratified Columnar Epithelium ^
Characteristics: Single layer of cells with different heights; some do not reach the free surface.
Examples: Male sperm- carrying ducts (nonciliated) and trachea (ciliated)

Stratified Squamous Epithelium ^
Characteristics: Thick membrane composed of several layers of cells
Examples: Forms the external part of the skin's epidermis (keratinized cells), and linings of the esophagus, mouth, and vagina (nonkeratinized cells)

Stratified Cuboidal Epithelium ^
Characteristics: Rare in the body, typically 2 cell layers thick
Examples: Swear and mammary glands

Stratified Columnar Epithelium ^
Characteristics: Limited distribution in the body
Examples: Pharynx, male urethra, lining some glandular ducts

Transitional Epithelium ^
Characteristics: Several cell layers, basal cells are cuboidal, surface cells are dome shaped
Examples: Lines the urinary bladder, ureters, and part of the urethra

Homeostasis Lab

Medical Terms & Homeostasis

There are many medical terms that we have learned in the last few days.  After seeing lists and lists of all these terms, I'll admit that I was starting to stress already.  I thought there was no way that I was going to be able to remember all these words and their definitions.  I proved myself wrong, after reviewing all of the terms and the definitions, a lot of them are common sense.  For example: Medial means middle.  Distal means distance.  Just by looking at those words you could probably infer what each term means by taking an educated guess.  Not all words are common sense.  I had a hard time remembering what Endocrine and Integumentary meant.  I know that Endocrine is affected by the removal of the thyroid gland.  Integumentary protects underlying organs from drying out and mechanical damage.  Other words I knew a little bit about and I could make an educated guess of what the term had to do with.  Some of the terms I related to my life, for example: everyone always tells me that I have a great metabolism.  So I narrowed down my choices and it made sense that the definition of metabolism would be all chemical reactions occurring in the body.  There were some new words that I didn't know, but there always seems to be "hints" in the words that help me with figuring out what the definition is.

Homeostasis is a state of body equilibruim or stable internal environment of the body.  It was very interesting reading about homeostasis.  The body has trillions of cells that are moving constantly and little usually goes wrong.  Little goes wrong because of homeostasis, it has the ability to maintain stable internal conditions even though the outside world changes all the time!  Communication within the body is needed for homeostasis to be effective.  Homeostasis has at least 3 interdependent components including: receptor > control center > effector.  Most control mechanisms are negative feedback mechanisms.  After humans age, their body's control system become less effective and less stable, this is called homeostatic imbalance.

At the moment I have a better understanding of the medical terms but that is because homeostasis is so complex.  After awhile I will understand all of the steps to homeostasis and I will also know all of the medical terms and their definitions.