Types of Tissues (:

Well first of all, tissues are a group of similar cells that do are responsible for a specific function.  The study of tissues is called histology.  There are four major types in the human body which are epithelial, connective, muscle, and nervous.  These tissues are responsible for the association, assembly, and interactions to form organs that have certain functions. I am going to talk about epithelial tissues and what they do.

Epithelial tissues: Responsible for covering all free body surfaces

• Covers the organs
• Forms the inner lining of the body cavities and lines our hollow organs.
• The basement membrane holds epithelial tissue to underlying connective tissue.
• Lack blood vessels
• Tightly packed

Epithelial tissues are classified by shape and the number of layers of cells. 

 Squamous: Thin, flattened cells

 Cuboidal: Cubelike cells

Columnar: Elongated cells

Simple:Single layer of cells

Stratified:2 or more layers

Simple Squamous-Single layers of thin, flattened cells. They fit tightly together and their nuclei are usually broad and thin.

-Common at sites of diffusion and filtration.

-Lines the alveoli of the lungs

-Forms the walls of capillaries, lines the blood and lymph vessels, and covers membranes that line body cavities

Simple Cuboidal-Single layer of cube-shaped cells which usually have a central location for the spherical nuclei.

-Lines the follicles of the thyroid gland, covers the ovaries, and lines the kidney tubules and ducts of glands

           *salivary glands

           *pancreas

           *liver

Simple Columnar-Single layer of elongated cells with nuclei that are at the same level near the basement membrane.  

-Cells can be ciliated or non ciliated. 

-They move constantly

-Some simple columnar cells are used for absorption.

Psuedostratified Columnar Epithelium-Appear stratified or layered, but really aren't.
-This layered effect occurs because the nuclei are at 2 or more levels in the aligned cell row.
-These cells vary in shape and reach the basement membrane.
-These types of cells have cilia

Stratified Squamous Epithelium-Many layers of cells, which make the tissue relatively thick.
-Cells nearest the free surface get flattened the most.
**Fun Fact-the epidermis is stratified squamous epithelium.

Stratified Cuboidal Epithelium-2-3 layers of cuboidal cells that form the lining of a lumen.
-Provides more protection for cells
-Lines the larger ducts of the mammary glands, sweat glands, salivary glands, and pancreas

Stratified Columnar Epithelium-Made of several layers of cells
-Elongated cells
-Found in part of the male urethra and ductus deferens.

What in the world is Homeostasis??

In middle school, teachers begin teaching us about homeostasis, but the question is; do we really understand it?  In fancy terms, homeostasis is the ability to maintain a relatively stable internal environment in a constantly changing outside world.  The process of homeostasis involves chemical, thermal, and neural factors that interact.  In simple terms, I understand homeostasis as the body's ability to stay cool and collected internally while the outside world is constantly changing.  Homeostasis involves many different things like receptors, a control center, and effectors. 
Receptors are responsible for keeping an eye on the body and responding to the changes it makes.  After the receptors see what the body needs it forwards it to the control center.  The Control Center gains the information from the receptors and it sets the range at which a variable will be maintained.  The control center makes the decision of an appropriate response to the stimulus.  Many scientists consider the control center as the brain in homeostatic mechanisms.  The control center sends signals to an effector, which can range anywhere from muscles to other structures that get signals from the "brain".  When the effector receives the signal, changes can occur to correct the difference by either increasing it with good feedback or decreasing it with negative feedback.

When homeostasis is disturbed, our bodies try to fix it by changing one or more physiological processes.  This helps us adapt to stress which includes activating the Hypothalamic-Pitauitary-Andrenal Axis with the nervous system and endocrine reactions of our bodies.  This can cause psychological distress and possibly even psycho-somatic disorders.

Diagram of homeostasis (:

Sources:
http://www.biology-online.org/dictionary/Homeostasis

http://en.wikipedia.org/wiki/Human_homeostasis

Homeostasis lab!

This graph shows how the temperature changed with the different intervals of jumping jacks

Just recently we started learning about homeostasis.  Homeostasis is the ability to remain stable.  My group and I decided to do jumping jacks to test our temperature and how quickly it would rise.  After ten jumping jacks the temperature of Tenchita's body began to rise.  She had a three minute rest to let her body cool down, making the temperature drop about four degrees.  After she was rested, she did 25 jumping jacks.  After 25 jumping jacks her temperature rose from 27 degrees to almost 33 degrees.  This represented that the more jumping jacks or more activity you do, the higher your temperature increases.  Homeostasis was exemplified in this lab due to the fact that it showed how the body heats up, but also cools itself down when relaxation takes place. 

The graph below shows what her temperature started out as then as it progressed with 10 jumping jacks, cooled while at rest and then shot back up after 25 jumping jacks.

In order to complete this experiment on your own, you could follow these few simple steps (=

Materials Needed

• Thermometer
• Person capable of doing jumping jacks
• Time

First you would go to a room temperature area so that it wouldn't affect the temperature change.  Next you would take the temperature of the participant that is going to be doing the jumping jacks. Write how high the temperature is on a piece of paper.  Then have the participant do 10 jumping jacks approximately for 25 seconds.  After they complete that task, take the temp. right away.  Write that number down.  Next step is to take the temperature of the person's body after they rest for about five minutes.  After that temperature is taken have the participant do 25 jumping jacks for approximately 25 seconds.  After all of this is completed, graph the numbers and see how much the numbers changed from doing 10 jumping jacks to 25 in the same time interval.