Tissues ( ESSAY )

Our whole body are made of cells. About 7 octillion of them, to be precise. And every cells in your whole body, every single one of those 7 octillion cells, have a specific job, to keep the homeostasis going on in you body. Homeostasis, by the way, is a balance of materials and energy to keeps us alive. Back to the cell. Now every cell has a different job, but those jobs sometimes are very identical. Like, if a cells job is to "put garbage on garbage bin", and another cells job is to "pick up garbage from the ground", those job are very similar, and cells that have very similar jobs group together to form "tissues" that form a common function or goal to achieve homeostasis to keep you alive. FINALLY were in the part where we talk about the heading of this essay... Anyway, tissues themselves have different functions. Four different functions to be precise:

• Nervous Tissue "Control and communication"
• Muscle Tissue "Movement"
• Epithelial Tissue "Cover and protect your body"
• Connective Tissue "Provide support"

Nervous tissue control your communication and control. Nervous tissue forms the nervous system. Our nervous tissue has two big functions: to sense stimuli and to send electrical impulses through the body, often in response to the stimuli. This tissue are also made up of two different cell types: neuron and glial cells. Neurons are the specialized building blocks of the nervous system, they're what generates and conduct the electrochemical nerve impulses that let you think, dream, or do anything. They are also all over your body. When you touch a fuzzy dog, or a cold metal, or hot water, the neurons in your skin's nervous tissue send stimuli to your brain - not someone else's brain - that sense that stimuli and then you can feel the world around you, like fuzziness, coldness, or the unwelcoming feeling when you dip your hand in boiling water. No matter where they are, the neuron has a same anatomy, consisting of the cell body, dendrites, and the axon. The cell body, also called soma, is the "headquarters", containing a nucleus, mitochondria, and DNA. The dendrites, look like the root of the trees they're named after, and they're job is to collect the stimuli and information from other cells. They're the listening end. The long rope-like axon is the transmission cable - they carry messages to other neurons, and muscle, and glands, and stuff. The other type of nervous cell, the glial cells, are like the neurons pit crew, providing support, insulation, protection, and tethering the neuron cell to the blood vessels.
But your whole body would be utterly helpless if there are nothing or nobody that can do the commands the neurons send, which is why we have muscle tissues. Unlike our nervous tissue, the muscle tissue can contract and move. Muscle tissue also are well-vascularized, meaning it got a lot of blood coming and going, and it comes in three 'flavors', skeletal, cardiac, and smooth. Skeletal muscle tissue are found in our bone. This is the only one of the three that we can control. The other ones all work involuntarily, which is great, so we don't have to think to breath. The cardiac muscle tissue forms the walls of our heart, and works involuntarily. This tissue is only found in our heart. And finally we have the smooth muscle tissue, which lines the walls of most of your blood vessels and hollow organs.
Now we can finally talk about the epithelial tissue, which is the most awesomely named muscle tissue for me. The epithelial tissue is great at separating other cells from each other. It's like a burly gym teacher that knows what to do to keep his students in order. The epithelial tissue creates order where otherwise there would be total chaos and mayhem. Because we, humans, are filled with complex, fidgety, feisty systems that need to be separated to some extend if we want our different parts to achieve anything.
Now we will reach the most abundant and diverse of the four tissue type, the connective tissue. This is the stuff that keeps you -and me- looking young, makes up the skeleton, and delivers oxygen and nutrients throughout our body. It's what holds you, and me, together, in more ways than one. Connective tissue is pretty much every in our body, but the amount of how much is found in different parts of the body vary from organ to organ. For instance, the skin is made of mostly connective tissue, while the brain has very little, since it's almost all nervous tissue. There are four major classes of connective tissue: Proper, cartilage, bone, and most surprisingly, blood. Here are a list of what our connective tissue does to keep our homeostasis on play: Binding and supporting; protecting; insulating; storing reserve fluid and energy; transporting substances within our body; and also for movement. There is no other tissue that can boast of such high diversity as the connective tissue. But if there is so much diversity how can we group all these "diversityness" into one tissue group??? Well there are three factors that all the "branches" of the connective tissue have in common and the one that make them special : First, they share a common origin. They all form from mesenchyme, a loose and fluid type of embryonic tissue, which makes "vested" on them the ability to move oneself, which all other tissue type don't have. They also have different degrees of vascularity, or blood flow. Finally, and as strange as it may sound, all connective tissue are mostly composed of nonliving material called the extracellular matrix.

P.S. : I mostly gathered the information to create this post from Crash Course. If you don't know 'em, check out their youtube channel, they are amazing.