Function of kidney: Balance the body's fluids

One of the key tasks of the kidneys is to regulate fluid and electrolyte balance by controlling the volume and composition of the urine. These adjustments are essential because the osmolarity of body fluids must be around 300 milliosmols/liter.

All the cells in the body, apart from those of the outer skin, are surrounded by a fluid called the extracellular fluid (ECF).

80% of ECF is interstitial fluid (which includes lymph, synovial fluid, cerebrospinal fluid, GI tract fluids, and fluids in the eyes and ears), and 20% of ECF is blood plasma.

For the cells of the body to work properly, the extracellular fluid needs to have a stable composition of salts - such as potassium and sodium - and acidity (often referred to as pH).

The kidneys are the most important organs for regulating the characteristics of body fluids. This regulation is apparent in the control of
*Blood volume,
*Extracellular fluid volume and
*Osmolality of body fluids.

Osmotic pressure (created by the dissolved electrolytes in body fluids) and hydrostatic pressure (created by the water in body fluids) are the main forces behind any molecular movement between body compartments.

99 % of water and Na is re-absorbed by tubules to maintain osmotic balance. If more Na is excreted, this leads to water excretion and dehydration.

The kidneys are central to maintaining these correct balances and the effective functioning of all the cells of the body.

Thirst also plays a vital role in controlling some characteristics of body fluids. The salt and water balance is maintained by a series of hormones acting on the kidney. The kidneys recognize and act upon a series of messages that vary according to how much fluid is drunk.

If an excess of fluid is drunk, the body fluids become more diluted, and the kidneys excrete a more dilute urine, getting rid of the excess that has been taken in.
Function of kidney: Balance the body's fluids

The functions of protein in human body

Protein molecules serve as some of the major structural elements of living systems.

There are thousands of different proteins with a specific functions.

Proteins have many different biological functions Proteins are classified according to their biological roles.

Enzymatic Proteins
Protein found in many enzymes. Enzymes are catalysts, meaning that they increases the rate of reactions e.g. food digestion , sometimes by more than a million times without being destroyed.

Enzymes necessary for the digestion of carbohydrates, fats, proteins.

Transport Proteins
It transport iron, fats, minerals and oxygen.

Structural Proteins
It serves as structural components of cells and organisms. It is the fundamental structural material of every cell in the body.

This functions depends on specific association of protein subunits with themselves as well as with other proteins, carbohydrates or others.

Hormonal Proteins
Hormones are chemical messengers secreted into the bloodstream by various organs, such as the liver. It regulates certain activities so that a constant internal environment is maintain.

For example insulin that plays a key role in regulating the amount of glucose in the blood. It is released from the pancreas in response to a rise in blood glucose levels.

Defensive Proteins
Protein used to build special white blood cells and antibodies as a part of the body’s immune systems for fighting invasion and infection by foreign substances.

Provide energy as last resort
Actually carbohydrates are the primary fuel source but in times of need, protein can be burned to supply energy.

Build and maintain the body
Proteins are used for building and maintaining body tissues. All this tissue must be repaired and replaced.
The functions of protein in human body

Mineral in Human Bodies

Mineral in Human Bodies
In general, the function of minerals in the body can be divided into two categories, namely, building body tissue and regulating numerous processes.

Potassium, sulfur, phosphorus, iron and other minerals are structural components of soft tissue.

Sodium is principally found in extracellular fluid (bone is an exception), where it is the chief cation, and thus it is considered mainly as a primary determinant of body fluid osmolarity as well as the maintainer of body fluid pH.

Intracellular fluid contains much smaller amounts of sodium though these stores, and perhaps the sodium of the bone also serve in this capacity.

It is also important to mention that the energy for impulse transmission in the nerve and its action potential derive from the potential energy represented by the separathion of sodium and potassium across the cell wall.

On the other hand, calcium, together with phosphorus, magnesium and fluorine are components of bone and teeth. Deficiencies during the growing years cause growth to be stunted and bone tissue to be poor quality.

A continual intake of mineral is essential for the maintenance of skeletal tissue in good condition

Minerals are an integral part of many hormones, enzymes and other compounds that regulate physiological functions in the organism.

For example, iodine required to produce the hormone thyroxine, chromium is involved in the production of insulin and hemoglobin is an iron containing compound.

Thus, production of these substances in the organism depends on adequate intake of the involved minerals.

Minerals can also act as catalysts. Calcium is a catalysts in blood clotting. Some minerals are catalysts in the absorption of nutrients from the gastrointestinal tract, the metabolism of proteins, fat and carbohydrate and the utilization of nutrients by the cell.

Mineral dissolved in the body fluids are responsible for nerve impulses and the contraction of muscles, as swell as for water and acid base balance.

Minerals play an important role in maintaining respiration, heart rate and blood pressure within normal limits.

The deficiency of minerals in the diet may lead to severe chronic clinical signs of disease, frequently reversible after their supplementation on the diet or following total parenteral nutrition.

The influence of minerals on biochemical reactions in living systems also make it possible to use them intentionally in many food processes.
Mineral in Human Bodies

Digestion and absorption at infant age

Digestion and absorption at infant age
The complex process of digestion/absorption can be optimally effective only when the GI tract and accessory organs are totally develop and fully functioning.

Not only must the muscular tube (alimentary canal) with it a mucosal lining and endocrine cells be operating efficiently in conjunction with the nervous system, but the accessory organs (pancreas, liver, and gallbladder) with their important digestive secretions also must be physiologically mature.

The feeding of infants is based on primarily in degree of maturation of the GI tract and accessory organs.

Good examples of the emphasis on GI tract maturity are the care given to the fat in infant formula and the time and sequence of the introduction of various foods into the infant’s diet.

Only those fats possessing an ease used in commercial formulas and the introduction of solid food, beginning with baby cereal usually occurs no earlier than 4 months of age.

The infant pancreas, although structurally mature at term, is usable for several months to produce enzymes sufficient for effective digestion.

Pancreatic lipase, alpha-amylase and the proteolytic enzymes are in too short supply to accommodate digestion of a mixed diet. Digestion of fat is a real concern because there is a deficiency of bile salts from the liver as well as low lipase release from the pancreas.
Digestion and absorption at infant age

Calcium in Our Body: Function and Deficiency

Calcium in Our Body: Function and Deficiency
Calcium is vital for the formation of strong bones and teeth and for the maintenance of healthy gums. It is also important in the maintenance of a regular heartbeat and in the transmission of nerve impulses.

Calcium lowers cholesterol levels and helps prevent cardiovascular disease. It is needed for muscular growth and contraction, for the prevention of muscle cramps. It may increase the rate of bone growth and bone mineral density in children.

This important mineral is also essential in blood clotting and helps prevent cancer. It may lower blood pressure and prevent bone loss associated with osteoporosis as well. Calcium provides energy and participates in the protein structuring of RNA and DNA.

It is also involved in the activation of several enzymes, including lipase, which breaks down fats for utilization by the body. In addition, calcium maintains proper cell membrane permeability, aids in neuromuscular activity, helps to keep the skin healthy, and protects against the development of preeclampsia during pregnancy, the number one cause of maternal death. If high blood pressure develops due to pregnancy, it can be reduced by calcium intake.

Calcium protects the bones and teeth from lead by inhibiting absorption of this toxic metal. If there is a calcium deficiency, lead can be absorbed by the body and deposited in the teeth and bones.

Calcium deficiency can lead to the following problems: arching joints, brittle nails, eczema, elevated blood cholesterol, heart palpitation, hypertension (high blood pressure), insomnia, muscle cramps, nervousness, numbness in the arms and/or legs, a pasty complexion, rheumatoid arthritis, rickets and tooth decay.

Deficiencies of calcium are also associated with cognitive impairment convulsions, depression, delusions and hyperactivity.
Calcium in Our Body: Function and Deficiency

How Gastrointestinal Tract Function?

How Gastrointestinal Tract Function?
An examination of the various mechanisms in the gastrointestinal tract that allow to be ingested, digested, absorbed, and then its residue to be excreted reveals the complexity of the digestion/absorption process. Normal digestion and absorption of nutrients is dependent not only on a healthy alimentary canal but also on an exquisite integration of the digestive system with the nervous system, endocrine system, and circulatory system. An excellent example of this integration of systems is the finely controlled emptying of chyme from the stomach into the small intestine.

The many factors influencing digestion and absorption, including the dispersion and mixing of ingested food, the quantity and composition of gastrointestinal secretions, status of the enterocytes, expanse of intestinal absorptive area and the transit time of intestinal contents must be coordinated so that nourishment of the body can occur while homeostasis of body fluids is maintained. Much of the coordination required is provided by regulatory peptides, some of which are provided by the nervous system as well as by the endocrine cells of the gastrointestinal tract.
How Gastrointestinal Tract Function?