The Body Shop - Research Review

The article, "The Body Shop," was very interesting to me. It was about how, just 15 years ago Bob Langer and his colleague Joseph Vacanti pioneered a remarkable new process that involved the growing of human tissues in the lab. How interesting is that! This is the first time I have heard of anything like this being done. A shocking discovery I had made while reading the article was that earlier in 1987, Langer and Vacanti couldn't get their work published but now they are acknowledged as the fathers of the field of tissue engineering.

Just think about it without these two men we would have what is today "neo-organ." You may be asking yourself what that is. But it is tissue engineered skin, that was approved by the U.S Food and Drug Administration. This tissue engineered skin aids burn victims and patients with severe skin sores or ulcers.

Another positive attribute is that in the not-too-distant future, the lab-grown cartilage and bone could relieve arthritis sufferers, while blood vessels, cardiac valves and muscle tissue that could save thousands of cardiovascular disease patients. Wow! Developing these custom-made hearts, livers, breasts, corneas, kidneys, bone marrow and bladders could offer elegant solutions to most life-threatening illnesses. How great would that be?

Dr. Joseph Vacanti says, "We can't say what the time-line will be." "But there are thirty plus tissues we're experimenting on in our lab."  

 

This human heart valve was grown in the lab.

Imitating Life

Looking up above at that picture you may be wondering how that human heart valve was grown in a lab, so here some explanation provided by the article.

Cultivating tissues in the lab requires closely mimicking the environment in which cells naturally grow. This turns out to be a tall order. Unlocking the biochemical signals that influence growth and development was the first step on the road to tissue engineering. By adding the right combination of compounds, scientists coax cells into growing and proliferating.

But, to produce biologically useful tissues like cartilage and heart valves, tissue engineers must also pay special attention to the physical environment in which cells grow. In nature, the circulatory system gives each individual cell in a tissue access to nutrients and a means of waste removal.

Scaffolding 
One of Langer's major contributions was his work in biodegradable materials that can serve as scaffolding on which cells can be seeded. Joseph Vacanti deserves credit for the idea of the scaffold itself.

"The scaffold looks like strands of spaghetti attached together," according to Langer. "The cells are seeded 2 to 3 millimeters apart and the whole apparatus is bathed in a nutritive media." The biodegradable scaffolding provides each cell with better access to nutrients and waste removal. Additionally, since the scaffolding can be molded into any shape or size, the tissue can be custom grown for the intended recipient.

Look At This Example!!!!

After this human ear is removed,
the mouse will remain healthy.

To grow an ear like the one on the mouse pictured above, tissue engineers molded the biodegradable scaffold into the proper size and shape. Researchers then "seed" the scaffold with young cartilage cells and surgically implant the mold under the skin. The first question that came to my mind when I was reading was how and why didn't the mouse reject the human tissue then I found out that the hairless mouse was specially bred to lack an immune system that might reject the human tissue, and would nourish the ear as the cartilage cells grow.

To conclude it is said that in the future, bits of scaffolding seeded with young cells could be implanted into ailing organs, where the body's own biochemistry would direct the young cells to grow into a "patch" of healthy tissues.
"Both functions are important," according to Joseph Vacanti. "but, in many circumstances, the shape is less important than the exchange of nutrients. "

Tissue: The Living Fabric

Connective Tissue

Connective tissue is found everywhere in the body.  

Each epithelium is given two names. First name indicates the number of cell layers present, and the second describes the shape of its cells. There could be; simple epithelia (single cell layer) typically found where absorption and filtration occur, stratified epithelia (two or more cell layers stacked on top of one another) commonly found in high-abrasion areas where protection is important like the skin surface and the lining of the mouth. Epithelial cells have six irregular sides that looks like a honeycomb. There are three common shapes of epithelial cells; squamous cells are flattened and scalelike their nucleus are flattened disc, cuboidal cells are boxlike approximately as tall as they are wide with a nucleus that is spherical, and columnar cells are tall and column shaped their nucleus is elongated from top to bottom and located towards the cell base.

Simple Squamous Epithelium
Function: allows passage of materials by diffusion and filtration in sites where protection is not important
Location: air sacs of lungs. lining of heart, blood vessels, lymphatic vessels
Two simple squamous epithelia in the body have special names that reflect their location. Endothelium "inner covering" and the Mesothelium "middle covering."

Simple Cuboidal Epithelium 
Function: secretion and absorption
Location: kidney tubules, ducts and secretory portions of small glands, ovary surface

Simple Columnar Epithelium
Function: absorption, secretion of mucus, enzymes, and other substances
Location: nonciliated type lines most of the digestive track (stomach to anal canal), gallbladder, and some regions of the uterus

Stratified Squamous Epithelium
Function: protects  underlying tissue in areas subjected to abrasion
Location: epidermis of the skin, lining of the esophagus, mouth, and vagina.

Stratified Cuboidal Epithelium
Location: quite rare in the body, mostly found in the ducts of some of the larger glands like the sweat and mammary glands with typically two layers of cuboidal cells

Stratified Columnar Epithelium
Location: rare in the body but small amounts found in the pharynx, the male urethra, and the lining some glandular ducts

Pseudostratified Columnar Epithelium
Function: secretion, particularly of mucus, propulsion of mucus by ciliary action.
Location: nonciliated type in males sperm-carrying ducts and ducts of large glands, lines the trachea, and most of the upper respiratory tract. The cell nuclei lie at different levels above the basement membrane, but only the tallest reach the free surface of the epithelium.

Transitional Epithelium 
Function: stretches readily and permits distension of urinary organ by contained urine.
Location: lines the ureters, bladder, and part of the urethra
The ability of transitional cells to change their shape or undergo "transitions" allows a greater volume of urine to flow through.

Muscle Tissue
Muscle tissues are highly cellular, well-vascularized tissues that are responsible for most types of body movement.

Skeletal Muscle
Function: voluntary movement, locomotion, manipulation of the environment, facial expression, voluntary control.
Location: in skeletal muscles attached to bones or occasionally to skin

Cardiac Muscle
Function: as it contracts, it propels blood into the circulation, involuntary control
Location: the walls of the heart

Smooth Muscle
Function: propels substances or objects (foodstuffs, urine, a baby) along internal passageways, involuntary control
Location: mostly in the walls of hollow organs

Nervous Tissue
Function: transmit electrical signals form sensory receptors and to effectors (muscles and glands) with control their activity
Location: brain, spinal cord, and nerves
The main component of the nervous system the brain, spinal cord, and nerves which regulates and controls body functions. Containing two major cell types.

Homeostasis & Medical Terms

Homeostasis
I can define homeostasis as the ability to keep your internal conditions stable even though your outside world is continuously changing. It is a dynamic state of equilibrium, or balance, in which internal conditions vary, but always within relatively narrow limits. Maintaining homeostasis is complicated. Like when you are outside and the weather is cold your internal body temperature will change but will then become stable and control itself. Then if you go inside a nice warm place your outside world continuously changed but your body temperature was still stable.

Negative Feedback
Most homeostatic control mechanisms are negative feedback mechanisms or loops. In negative feedback systems, the output that shuts off the original stimulus or reduces its intensity. If your mechanisms get or overwhelmed and destructive positive feedback will take over (homeostatic imbalance).

Positive Feedback
Positive feedback mechanisms , the result or response enhances the original stimulus so that the activity (output) is accelerated. Mechanism is positive because the change that occur proceeds in the same direction as the initial disturbance, causing the variable to move further from its original value or range.

Medical Terms:
Anterior (ventral) - Toward or at the front of the body; in front of  (the breastbone is anterior to the spine)
Some anterior body regions are: ear, nose, mouth, neck, shoulder, armpit, breast, arm, the front of the elbow, forearm abdomen, the reproductive organs, wrist, palm, finger, ankle.
Inferior (caudal) - Away from the head end or towards the bottom of the body towards the feet. (the navel is inferior to the chin)
Posterior (dorsal) - Toward or at the back of the body; behind (the heart is posterior to the breastbone).
Superior (cranial) - Toward the head end or upper part of the body; above (the skull is superior to the ribs)
Distal - Farther from the origin of a body part or the point of attachment of a limb to the body trunk. example: The knee is distal to the thigh.
Medial- Towards the middle of the body. (from your side towards your belly button)
Lateral - Away from the mid-line away from the on the outer side of the body. (arms are lateral to the chest)
Proximal- Closer to the origin of a body part or the point of attachment of a limb to the body trunk. (elbow is proximal to the wrist)

Body Planes
Transverse plane cuts the body in half horizontally dividing the superior part and the inferior parts of the body.
Frontal plane lies vertically dividing the body into anterior and posterior parts
Sagittal plane cuts the body from top to bottom, dividing it into left and right portions.

The Organization Of The Body

Chemicals form to make molecules ----> Cells are made up of molecules ----> Tissues are made up of similar types of cells ----> Organs are made up of different types of tissues ----> Organ system are groups of organs that work together closely ----> Organismal is made up of many groups of organs.