The human body is made up of many (millions) of cells. Cells' most basic
needs are energy, oxygen and water in which to maintain their (cells)
environment in the body. The very first principle of planning diet is that the
food selected must first provide energy, water, and essential nutrients. In our
bodies, cells work together in unity with each other in order to support the
whole. The cells genes, decide the nature of the work to be done, hence the
genes are the blueprint that directs the production of enzymes which help to do
the cell's work.
Cells are then organised into tissues that perform their specific task.
An example can be made of muscle cells which join together to form muscle
tissue which can contract and relax. Tissues then group together to form organs
like the heart, kidneys etc. in the heart for example, muscle tissues, nerve
tissues, connective tissues as well as other types of tissues work together to
pump blood.
Body fluids supply the tissues continuosly with the necessary energy,
oxygen, water and building materials. The fluids always circulate to pick up
fresh supplies and deliver wastes to their point of disposal. The body's main
fluids are the blood and the lymph. The blood travels in the arteries, veins
and capillaries and also in the chambers (rooms) of the heart. As the blood
travels through the cardiovascular (heart) system, it delivers all the
necessary materials that cells need and picks up the wastes. The blood picks up
oxygen in the lungs and also releases carbon dioxide there. The blood
circulates to the lungs and then returns to the heart where it receives a
powerful “push” out to all the body tissues.
As it passes through the digestive system, the blood delivers oxygen to
the cells there, and picks up most nutrients from the intestine for
distribution elsewhere. Lymphatic vessels on the other hand pick up most fats
from the intestine and transport them to the blood. All the blood leaving the
digestive system is destined to the liver, which then chemically changes the
absorbed materials to make them better suited for use by other tissues. Later
in passing through the kidneys, the blood is cleaned from wastes which are excreted
via urine.
This process simply means that we must drink enough water in order to
replace the water lost each day. Cardiovascular fitness is also important.
Healthy red blood cells also play an important role in carrying oxygen to all
the other cells, enabling them to use fuels for energy. Since red blood cells
arise, live and die within four months, the body replaces them constantly, a
manufacturing process that requires many essential nutrients from food. Medical
science hence concludes that many blood disorders are caused by dietary
deficiencies or an imbalance in vitamins or minerals; the blood is very
sensitive to malnutrition.
In addition to nutrients, oxygen and wastes, the blood carries chemical
messengers called hormones and these are taken from one system of cells to
another. Hormones communicate changing conditions that demand responses from
the organs of the body. Hormones are released into the blood by the help of
glands. Example when the pancreas detects that there's a high concentration of
the bloods sugar (glucose), it releases a hormone called insulin. Insulin
stimulates muscle and other cells to remove glucose from the blood and store
it. When the blood glucose level falls, the pancreas secretes another hormone
(glucagon) to which the liver responds by releasing into the blood some of the
glucose it stored earlier. Thus normal glucose levels are maintained.
Nutrition affects the hormonal system. People who become extremely thin
have an altered hormonal balance that may make them unable to maintain their
bones. People who eat high fat diets on the other hand have hormone levels that
may make them susceptible to certain cancers. Hormones also affect nutrition,
along with the nervous system, they regulate hunger and affect appetite. They carry
messages to regulate the digestive system, telling the digestive organs what
kinds of food has been eaten as well as how much digestive juice to secrete.
Hormones also regulate the menstrual cycle in women and they affect the appetite change which is
often experienced during the cycle and during pregnancy. An altered hormonal
state is thought to be partly responsible for the lack of appetite sick people
experience. They also regulate the body's reaction to stress, suppressing
hunger and the digestion and absorption of nutrients. Thus it is that a
person's nutrition plays an important role in their hormonal state.
The body's other major communication system is, the nervous system. With
the brain and spinal cord as the central controllers, the nervous system
receives and integrates information from the sensory receptors all over the
body- sight, hearing, touch smell, taste, and others. Which communicate to the
brain the state of both the outer and the inner worlds, including the
availability of food and the need to eat. The nervous system also sends
instructions to the muscles and glands, telling them what to do.
The nervous system's role in hunger regulation is coordinated by the
brain. The sensations of hunger and appetite are perceived by the brain's regulatory
work, this goes on deep inside the brain centers without the person's (or
cortex's) awareness. Deep inside the brain, the hypothalamus monitors many body
conditions including the availability of nutrients and water.
The digestive tract sends messages to the hypothalamus by way of
hormones and nerves that signal hunger, which also stimulates the stomach to intensify its contractions and secretions thus making gurgling sounds. When the conscious mind of the cortex becomes conscious of hunger, you decide to eat.
However; the cortex can override such signals and allow a person to choose to
delay eating despite hunger or to eat when hunger is absent.
The hormonal and nervous systems often work together to respond to
physical danger known as the stress response or the fight- or -flight reaction.
All the organs of the body respond with amazing speed and depending on the type
of stress, e.g. If while walking on bare feet you accidentally step on a thorn,
the first impulse would be to jump and scream. The heart races to rush the
oxygen to the muscles and the blood pressure rises to deliver efficiently the
fuel the muscles need for energy. The liver pours glucose from its stores,
while the fat cells release fat. The digestive system shuts down to permit all
the body's systems to serve the muscles and nerves.
Our number one enemy in modern society is hence not a “saber tooth tiger
prowling outside our homes” but a disease called atheriosclerosis. When years
of fat have accumulated in the arteries and stresses that strain the heart
occur, combined with sudden high blood pressure, a heart attack follows or a
stroke which is dibilitating (weakens the body/organs) and even lethal (causing
death). Daily exercise as part of a healthy lifestyle releases piled-up stress
and strengthens the heart's defense against atheriosclerosis.
The digestive tract, moves food through its various processing chambers
by mechanical means. The mechanical actions include breaking down, mixing by
the stomach, adding fluid and moving the tract's contents by peristalsis. After
digestion and absorption, wastes are excreted. Chemical digestion begins in the
mouth where the food is mixed with an enzyme in the saliva that acts on
carbohydrates. Digestion continues in the small intestine, where the liver and
gallbladder contribute bile that converts fat and where the pancreas and small
intestine donates enzymes that continue digestion so that absorption can occur.
A letter from your digestive tract:
To My Owner,
You and I are so close; I hope that I can speak frankly without
offending you. I know that sometimes I do offend, with gurgling noises and
belching at quiet times and oh yes, the gas. But please understand that when
you chew gum, drink carbonated drinks or eat hastily, you gulp air with each
swallow. I can't help making noise as I move the air along my length or release
it upward in a noisy belch. And if you eat or drink too fast, I can't help
getting hiccups. Please sit and relax while you dine. You will ease my task and
we'll both be happier.
When someone offers you a new food, you gobble it away, trusting me to
do my job. I try, it would make my life easier and yours less gassy, if you
would start with small amounts of new foods especially those high in fiber. The
bacteria that break down fiber, produce gas in the process. I can handle just
about anything if you introduce it slowly. But please: if you do notice more
gas than normal from a specific food, avoid it. If the gas becomes excessive,
check with a physician- the problem could be something simple or it could be
serious.
When you eat or drink too much, it just burns me up. Overeating causes
heartburn because acid juice from my stomach backs up into my esophagus. Acid
poses no problem to my healthy stomach, whose walls are coated with thick mucus
to protect them. But when my too-full stomach squeezes some of the contents
back up into the esophagus, the acid burns its unprotected surface. Oh and
those tight jeans you wear constrict my stomach, squeezing the contents upward
into the esophagus. Just leaning over or lying down after a meal may allow the
acid to escape up the esophagus because the muscular closure separating the two
spaces is much looser than other such muscles.
When heartburn is a problem, do me a favour and try to eat smaller
meals; drink liquids 30 minutes before a meal and 2 hours after a meal, but
never during meals; wear reasonably loose clothing; and relax after eating, but
sit up (don't lie down) rather take a walk. Sometimes your food choices
irritate me. Specifically chemical irritants in foods such as the “hot” chilli
peppers, black peppers (spices), chemicals in coffee, fat, chocolate and
alcohol.
By the way, I can tell you've been taking heartburn medicines again. You
must have been watching those TV commercials and letting them mislead you. You
need to know that antacids are designed only to temporarily relieve pain from
conditions such as heartburn and ulcers, while antibiotics and other
medications help heal ulcers. But in my case, the antacids trigger my stomach,
which is normal, to produce more acid. That's because when my normal stomach
acidity is reduced, I respond by producing more acid to restore the normal acid
condition. And the ingredients in the antacids can interfere with my ability to
absorb nutrients.
Please don't take acid reducers and acid controllers for my sake; these
reduce my acid so much that my job of digesting becomes much harder. In fact,
the drugs can cause indigestion and diarrhea. Thay can also mask the symptoms
of a hernia or an ulcer. A hernia can cause food back up in the esophagus, and
so feels like heartburn. Ulcer pain can be temporariy received by acid reducers
and controllers. Treating only the symptoms of a hernia or an ulcer can delay
its diagnosis and cure, I suggest you acsertain the cause.
When you eat too quickly, I worry about choking. Please take time to cut
your food into small pieces, and chew it until it is crushed and moistened with
saliva. Also refrain from talking or laughing before swallowing, and never attempt
to eat when you are breathing hard. When I'm suffering, you suffer too. When
constipation and diarrhea strike, neither of us is having fun. Slow, hard, dry
bowel movements can be painful, and failing to have a movement for too long
brings on headaches and ill feelings. Listen carefully for my signal that it is
time to visit the “little room” and make time for it, even if you are busy. The
longer you ignore my signal, the more time the colon has to extract water from
the feces, thus hardening them.
Please choose foods that provide enough fiber. Fiber attracts water,
creating softer, bulkier stools that stimulate my muscles to contract, pushing
the contents along. Fiber helps my muscles to stay fit, too, making elimination
easier. Be sure to drink enough water, because dehydration causes the colon to
absorb all the water it can get from the feces. And please work out regularly;
exercise strengthens not just the muscles of your arms, legs and torso, but
those of the colon too. When I have the opposite problem, diarrhea, my system
will rob you of water and salts. In diarrhea my intestinal contents have moved
too quickly drawing water and minerals from the tissues into the contents. When
this happens, please rest a while and drink fluids.
I'm willing to work with you, thank you for listening. I know we'll both
benefit from communicating like this, since we're in this together.
Your Digestive Tract
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