EYES and their functions

 

The eye is a complicated machine in itself with many parts. The eye works by refracting light rays to the retina. The light rays are adjusted through muscles and certain parts to create the right amount of light refracted to the retina. When light arrives at the retina it is converted to both chemical and electrical energy before being sent through optic nerves to the brain. In the retina, millions of rods containing rhodopsin that are responsible for night vision and convert the light into electrical impulses sent to the brain. The retina also contains millions of cones that contain iodopsin that are used for bright light vision, visual perception, and color perception. Light is transformed here also and sent to the brain through optic nerves. The brain translates what it receives through optic nerves so that we understand what we see.

Cornea

The cornea is the dome shape outer covering of the eye. It is like the windows of the car. It allows you to see but around you but protects you as well. The cornea is where most of the focusing of light occurs. It consists of many layers including the epithelium which is the tough outer layer that regenerates fairly quickly. The epithelium is usually removed or cut during many refractive procedures where the cornea is reshaped to focus light better.

Sclera

The Sclera is the outer white part of the eye that you can see. It provides protection and structure for the inner parts of the eye.

Conjunctiva and Lacrimal Glands

The conjunctiva is a mucus layer that keeps the eye moist. Infections to this area are known as the popular “pink eye.” Lacrimal glands are found on the outer part of each eye and are producers of tears.

Vitreous Humor and Aqueous Humor

The Vitreous Humor is gel like substance in the back part of the eyeball which provides the shape of the eyeball. The Aqueous Humor is the watery region in the form of the eye ball. It is separated into two regions, the anterior chamber in front of the iris and the posterior chamber behind it. The canal of Schlemm drains water in this region and is sometimes blocked off leading to the disease known as glaucoma or other complications.

Sclera

The Sclera is the outer white part of the eye that you can see. It provides protection and structure for the inner parts of the eye.

Iris and Pupil

The Pupil is the dark, black circle of the eye. It contracts with brightness and expands during darkness allowing light to better transmit. The iris is the colored part of the eye. This coloring is due to pigment cells in tissue in the iris. The iris contains the sphincter pupillae, a muscle used to narrow the pupil, and the dilator pupillae, a muscle used to widen the pupil.

Lens

The lens is a clear layer behind the pupil that does just what a regular lens does. The lens main purpose is to focus light by changing its shape. The ciliary body are muscles attached to the lens that help the lens change it shape to better focus light to the retina.

Retina

The retina is the inner most layer of sensitive tissue. When light is transmitted here images can clearly be transmitted to the brain. The retina consists of many layers including layers of rods and cones. Many cells in the retina transform light into chemical and electrical energy that is transferred to optic nerves. The back center of the retina contains themacula. The Macula is a highly sensitive part of the retina. It is responsible for our detailed vision. The center of the macula is called thefovea which has a major role in detailed perception. When there is damage to the macula, we are unable to see finer details.

FUN FACTS

• The human eye blinks an average of 4,200,000 times a year.
• It's impossible to sneeze with your eyes open.
• Our eyes are always the same size from birth, but our nose and ears never stop growing.
• Our body has some natural protection for our eyes. Our eyelashes help to keep dirt out of our eyes. Our eyebrows are made to keep sweat from running into our eyes.
• The shark cornea has been used in eye surgery, since its cornea is similar to a human cornea.
• The number one cause of blindness in adults is diabetes.
• The eyeball of a human weighs approximately 28 grams.
• The eye of a human can distinguish 500 shades of the gray.
• The cornea is the only living tissue in the human body that does not contain any blood vessels
• People generally read 25% slower from a computer screen compared to paper.
• Men are able to read fine print better than women can.
• All babies are colour blind when they are born.
• Babies' eyes do not produce tears until the baby is approximately six to eight weeks old.

Muscles

Muscles are one of those things that most of us take completely for granted, but they are incredibly important for two key reasons: Muscles are the “engine” that your body uses to propel itself.  Muscles turn energy into motion just like a car engine or an electric motor would do. It would be impossible for you to do anything without your muscles. Absolutely everything that you conceive with your brain is expressed as muscular motion. The only ways for you to express an idea are with the muscles of your larynx, mouth and tongue to speck words and the muscles of your fingers when taking with your hands or even dancing, or running.

When most people think of “muscle,” they think about the muscles that we can see. For example, most of us know about the biceps muscles, abs muscles. But there are three unique kinds of muscles in the human body, which are skeletal muscles, smooth muscle, and cardiac muscle. Skeletal muscle is the type of muscle that we can see and feel. When a body builder works out to increase muscle mass, skeletal muscle is what is being exercised. They attach to the skeleton and come in pairs, one muscle to move the bone in one direction and another to move it back the other way. These muscles usually contact voluntarily.  Smooth muscle is found in your digestive system, blood vessels, bladder, airways, and in a female, the uterus. Smooth muscle has the ability to stretch and maintain tension for long period of time. Smooth muscles also contracts involuntarily, meaning that you do not have to think about contracting it because your nervous system controls it automatically. Lastly, the cardiac muscle is found only in your heart, and its big features areenduracne and consistency. It can stretch a limited way, like smooth muscle, and contract with the force of a skeletal muscle. It is a twitch muscle and only contracts involuntarily.

Smooth                                                   skeletal                                                  cardiac 

             

The Skeletal System

The skeletal system is made up of bones and teeth. The normal human body has 206 bones which are needed for variety of functions within the body. The role of bones extends beyond the function of giving your body its shape. There are many reasons why bones are important to the body.  One of the most important functions that bones have in our body is providing support and structure. Bones are the hardest and most rigid structures in our body. The skeletal system also plays an important role in the protection of the vital organs throughout the body. The skull and the backbone protect the central nervous system. This protective role is especially important because the central nervous system controls the rest of your body and is very fragile. The ribs also protect the vital organs in the chest, such as the lungs and heart.  The skeletal system is also closely interacts with the muscles system. Bones are necessary because the muscles need something to attach to in order to contract and cause motion. Bones are also important as a center for the production of blood cells.  Lastly, the bones are responsible for the regulation of calcium levels. Calcium levels in the blood have to be kept in a narrow range to make sure the nerves and muscles are about to properly work. Much of the calcium is stored in the bones. When the body needs more calcium, bone tissue can be broken down to increase the blood’s supply and excess calcium can be stored in bone tissue for later.

Some interesting facts about the skeletal systems are:

1. Babies are born with 300 bones.

2. We are about 1 cm taller in the morning than in the evening.

3.The tooth is the only part of the human body that can't repair itself.

4.The feel account for one quarter of all the human body's bones.

5. Some bones are stronger than steel.

The Brain

The brain is incredibly complex with all its different parts that make up it. There are parts that make up the brain: frontal lobes, Temporal lobes, occipital lobes, parietal lobes, brain steam, and cerebellum. The frontal lobes are the largest lobes of the brain, which are located behind the forehead.  They are prone to injury because they sit inside the front of the skull and near rough bony ridges. These lobes are involved in: planning, organizing, problem solving, memory, impulse control, decision making, selective, attention, controlling our behavior and emotions. The left frontal lobes specifically control speech and language.  The temporal lobes are located on the sides of the brain under the parietal lobes and behind the frontal lobes at about the level of the ears. And they are responsible for: recognizing and processing sound, understanding and producing speech, and various aspects of memory. The occipital lobes are located at the lower back of the head.  They are responsible of receiving and processing visual information, and canting areas that help in perceiving shapes and colors.  The parietal lobe is located behind the frontal lobes, the parietal lobes: integrate sensory information from various parts of the body, contain the primary sensory cortex, and tells us which way is up, help to keep us from bumping into things when we walk. The brainstem is composed of the midbrain, the pons, and the medulla, which is located at the base of the brain. It regulates basic involuntary functions necessary for survival such as: breathing, heat rate, blood pressure, and swallowing. It also plays a big role in alertness and sensation.  Located at the back of the brain, the cerebellum controls: balance, movement, coordination. The cerebellum also allows us to stand upright, keep our balance, and move around. 

The cool thing about the brain is that there are different learning styles from the right or left side of the brain. The concept of the left and right brain lately popped up in the 1960’s, but since has become a well-known part of human psychology. While we all use both sides of the brain, each of us has a dominate side, and these dominate side makes up for a huge part of our personalities.  Those with a right side dominant brain depend more on visual references for understanding and are often more time visual learners. They are more emotional, swayed by feelings, and are able to better understand and reflect on these feelings. The downsides are they send to be disorganized, lacking in time-management, and unable to prioritize well. The left brain is the side that handles organization and logic. They prefer schedules and deadline, and love rules and regulations. They are more auditory learners, and are better at using works to remember things rather than visual aids. They process ideas in a step-by- step, algorithmic way, and are therefore less prone to error. 

The Heart

The heart is the strongest muscle in your body, only the size of your fist. The human body is an amazing machine always working nonstop, day and night. Did you know that the average adult heart beats 72 times a minute; 100,000 times a day; 3,600,000 times a year; and 2.5 billion times during a lifetime. It pumps out 2,000 gallons of blood each day, and would need a kitchen faucet to be turned on all the way for at least 45 years to equal the amount of blood pumped by the heart in an average lifetime. That makes is equivalent to pumping nearly 1.5 million barrels of blood which is enough to fill 200 train tank cars. The heart is the hardest working part in your body. Every day it creates enough energy to drive a truck 20 miles. In a lifetime it is enough to drive to the moon and back. In recent research health experts now have proof that laughter is good medicine. A good laugh can send 20% more blood flowing through your entire body which is a perfect way to relieve stress. Another interesting fact about the heart is that you are more likely to have a heart attack on a Monday than any other day in the week.

 

Overview

My name is Brittany Fisher and I am attending Frederick Community to get my degree in medical assistance. One class I am taking this semester is English. English is defiantly is one of my least favorite class to take but I have to take it.  I’m not the best writer. In the class one of the assignments are to create a blog site. (Which you are reading now) I decided to do my first blog of an overview of what my blogs were going to be.  In the beginning it was really hard for me to think of topics because at first I had no clue what a blog was, doing some research defiantly helped. Thinking long about an idea on what interests me and I came up with the human body, since my major is medical assistance and I will need to learn everything about it to help others in my career. Learning different facts about the human body are entertaining and also knowable; they keep me wanting to learn more. There is so much to learn about the human body. For example, how it works, what it’s made of, and the different functions it does.

http://www.youtube.com/watch?v=9o-AMwU9Fgw

This YouTube video shows the mapping of the human body from top to bottom.  I like how it shows you the different layers of the body from the skin, bones, and the organs.