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Sunday, June 18, 2017

Tissue Issues

The Four Essential Tissues

What tissues? Kleenex? Puffs? No, Honey, it is the tissues found in your body. Tissues are a group of similar cells linked together doing the same job. “So, what are the four, exactly?” They are epithelial tissue, connective tissue, muscle tissue and nervous tissue.

We’ll start off with epithelial tissues that can be found in various part in your body such as pharynx, salivary glands and skin. Now these tissues are differentiated by firstly the shape and then the number of layers. There are three basic shapes for these tissues, columnar, cuboidal and finally squamous. For one layer, we call it simple. For multiple layers, we call it stratified. Now that you know the very basics, we can go in depth to the purpose of the different shapes.

Columnar, because it is more long (rectangular) than it is wide, hence it has more surface area in which it is excellent in absorption. You can find simple columnar epithelial tissues at the duodenum (microvilli) and stratified columnar epithelial tissues at the pharynx for protection.

Cuboidal, as the name suggests, it is more cube-like, hence it has more volume for storage, for example the kidney for secretion or salivary glands, stratified cuboidal epithelial tissues.

Last of all squamous, it is spindle shaped, hence can be thin enough to provide rapid exchange of gases. Simple squamous epithelial tissues can be found at the alveoli while the stratified squamous epithelial tissue can be found at the skin for protection.

We’ve still got three more special type of epithelial tissues such as transitional, pseudostratified and glandular epithelial.

For transitional, as the name suggests, trans means change shape. This transitional epithelial tissue can be found at your bladder. So make sure you don't keep your pee in for too long! There might be nasty bacteria in there, that can increase the risk of bladder infection.

Pseudostratified, pseudo meaning “fake” and stratified meaning “multiple layers”. Pseudostratified columnar can be found along your trachea.

Finally, glandular epithelial which can be found in exocrine and endocrine.

Congratulations to you if you’ve made it this far to connective tissues. What are connective tissues? Yes, yes, they are like wires. These tissues give strength, flexibility, structure. It is shock absorbent, also it acts like a medium for transport. There are two categories of the connective tissue, proper and specialized. Under proper, there’s loose and dense. Loose connective tissues are areolar, adipose and reticular. While for dense, we have regular, irregular and elastic. Under specialized, there are the bones, blood and cartilage section. And those were just the tip of the iceberg.

Get a little stretch! Here comes the muscle tissues! The initial thought of muscles leads to movement, right?! Well, muscles allow us to move be it involuntary or voluntary. For example, our hearts never stops beating, "bedok bedok" (unless you're immortal). This such movement is involuntary. While voluntary means that we have the control of our movement. We have three types of muscle tissues. The first is skeletal muscle tissue, whereby these tissues moves bones. The second one is smooth muscles, which provide movement in the hollow organs like the oesophagus, ie. pushing the food down mechanically. Lastly, we have our cardiac muscle tissue.

Nervous tissues. Oh, don't freak out just yet! Neurons! These are like your wiring in the house that transmits electricity. There are several types of neurons in our body that are for different functions. As for example, the multi-polar myelinated neuron basically has a distinct cell body, nucleus and dendrites (branched out structure), axon (one long branch that is stretched out from the cell body to the axon terminals).

Now how amazing is our body ? It feel like it is similar to a house! Epithelial tissues could be like the bricks of the house. Connective tissues are like the composites used, steel (reinforcement) and cement (matrix). Muscle tissues are the power source while nervous tissues are the electrical wires all around the house. So let us appreciate the components that makes up our body and eat healthy to keep our house strong!


Transitional Epithelium:
Pseudostratified Epithelium:
Glandular Epithelium:

Connective tissue mindmap: 

Diagram of Arm:

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