Category Zoology

The water inside our bodies is salty – in fact, it is as salty as seawater. Salt, or sodium, help maintain the body’s water balance – the amount of salt dissolved in the blood tells the hypothalamus how much water the kidneys should release as urine, and how much to keep. Alongside potassium, salt also plays an essential role in helping nerve cells make signals.

The human body contains many salts, of which sodium chloride (AKA common table salt) is the major one, making up around 0.4 per cent of the body’s weight at a concentration pretty well equivalent to that in seawater. A child’s body contains the equivalent of 28 teaspoons of salt, while an adult’s body has 40 teaspoons.

So a 50kg person would contain around 200g of sodium chloride – around 40 teaspoons. Since we lose salt whenever we sweat, it has to be continually replaced.

While excessive consumption of it has been linked to high blood pressure and stomach cancer, salt is a vital part of body chemistry, playing a key role in many functions, from the quality of blood to transmission of nerve signals.

Picture Credit : Google

The hypothalamus in the brain is responsible for monitoring water level. If it detects too little or too much water, it responds by telling the pituitary gland to release hormones that communicate with me kidneys and other organs.

Too little water

A shortage of water in the body is called dehydration. The body needs to take in more water and also to conserve the water already inside it.

• Low water alert: The pituitary gland releases a hormone into the bloodstream.
• Feeling thirsty: The hormone triggers an urge to drink.
• Dry mouth: The mouth feels dry, as water is sent to areas that need it more.
• Kidneys: The kidneys receive instructions to remove less water from the blood, so the body produces less urine.

Too much water

Too much water in the body is called overhydration. This condition is rare, but can be caused by illness or by drinking a large amount very quickly. Cells become too waterlogged to work and the blood pressure becomes too high.

• High water alert: The hypothalamus orders blood vessels to widen, which reduces blood pressure.
• Kidneys: The kidneys are ordered to extract more water from the blood, making more urine.

Picture Credit : Google

Urine can provide valuable clues about health. Dark urine is a sign that a person is dehydrated and needs to drink more. Tests can also detect pregnancy, some infections, hormone changes, and diabetes.

To test urine, a testing strip is dipped into a sample. The coloured bands react to different chemicals in the urine, revealing any abnormalities.

Urine is 94 per cent water. The rest is made up of dissolved substances the body has no use for. They include sodium, which is excess salt, and urea, the waste produced by the liver.

At the microscopic level, your body is constantly working to keep you healthy, even while you sleep. Complex chemical processes take place throughout the body, including the breakdown of proteins known as amino acids. When your body breaks down amino acids, ammonia is left over as waste. That’s not something you want in your body for long—ammonia is toxic to human cells.

Since ammonia is toxic to your body, you need a way to remove it. That happens partly in the liver, where the ammonia is broken down into the less-toxic chemical, urea. Urea then combines with water and gets flushed into your bladder through the kidneys as urine, protecting your body from its own chemical processes.

Picture Credit : Google

Water does many different jobs. It helps provide a transport system around the body. It also regulates body temperature, and lubricates parts so they work better.

Blood

Blood is mostly water, so it flows easily through blood vessels. Your blood is 92% water. Water carries nutrients and oxygen to all cells in the body.Water is required for breathing.Water moistens oxygen for breathing

Lymph

Watery lymph flows around the body, recycling chemicals and fighting germs. The lymphatic system works to keep body fluid levels in balance and to defend the body against infections. It is made up of a network of lymphatic vessels that carry lymph — a clear, watery fluid that contains proteins, salts, and other substances — throughout the body.

Saliva

Saliva moistens foods to help with eating and also kills germs in the mouth. Saliva is 99% water and 1% protein and salts. The normal daily production of saliva varies between 0.5 and 1.5 liters. The whole unstimulated saliva flow rate is approximately 0.3-0.4 ml / min. 

Sweat

Sweat is released through skin pores to help cool the body down. Composed of about 99 percent water, sweat evaporates on the skin’s surface, cooling the body and keeping it from overheating.Sweat secretions help you in other ways, too. They include dermcidin, an antibiotic peptide that appears to regulate bacteria growth on the skin and may fight infection.

Urine

Urine is a mix of excess water and chemicals from the blood. This colorless urine is sometimes due to drinking an excess of water, while other times it can signal a problem with the kidneys. If your urine is consistently clear or absent of color, you should see a doctor.

Joints

Many moving joints have a lubricating layer of liquid, called synovial fluid. With its egg white–like consistency, the principle role of synovial fluid is to reduce friction between the articular cartilage of synovial joints during movement. Synovial fluid is a small component of the transcellular fluid component of extracellular fluid.

Tissue fluids

Body tissues contain water, with lean tissue holding more than fatty tissue. Water is also contained inside organs, in gastrointestinal, cerebrospinal, peritoneal, and ocular fluids. Adipose tissue contains about 10% of water, while muscle tissue contains about 75%.

Cell cytoplasm

Cells need water for the chemical reactions that take place inside them. Water is also in the environment outside the cell. For example, water inside cells makes up about 46 percent of your body’s mass, and water outside the cells in body fluids accounts for another 23 percent.

Picture Credit : Google

The amount of water in a person depends on their age, gender and weight. The more water-rich muscles they have, the higher their water content. As we grow older, muscles shrink and water levels drops.

A newborn baby is almost three-quarters water – and the proportion of water in the body drops gradually from then on. Men contain more water than women, as they usually have more water-containing muscle.

The average adult male is about 60% water. The average adult woman is about 55% water because women naturally have more fatty tissue than men. Overweight men and women have more water, as a percent, than their leaner counterparts.

The percent of water depends on your hydration level. People feel thirsty when they have already lost around 2-3% of their body’s water. Mental performance and physical coordination start to become impaired before thirst kicks in, typically around 1% dehydration.

Although liquid water is the most abundant molecule in the body, additional water is found in hydrated compounds. About 30-40% of the weight of the human body is the skeleton, but when the bound water is removed, either by chemical desiccation or heat, half the weight is lost.

Body chemistry

Water is essential ingredient of body cells. The millions of chemical reactions that power life take place in the water contained in the body’s cells. Different body tissues contain varying amounts of water, depending on their function. Muscle contains three times more water than bone.

Picture Credit : Google

Brainstem: acts as a relay center connecting the cerebrum and cerebellum to the spinal cord. It performs many automatic functions such as breathing, heart rate, body temperature, wake and sleep cycles, digestion, sneezing, coughing, vomiting, and swallowing.

The brain stem has 3 areas:

• midbrain (also called the mesencephalon)
• pons
• medulla oblongata

The brain stem sends information to and from the other parts of the brain to the rest of the body and controls:

• breathing
• body temperature
• blood pressure
• heart rate
• hunger and thirst
• digestion of food

More specific functions of each part of the brainstem are dependent of the cranial nerve nuclei and tracts that reside in each area. The medulla oblongata controls the respiratory function, cardiovascular system, as well as gastrointestinal and digestive activities. The pons is involved in controlling movements of the body and equilibrium. Finally, the midbrain controls eye movements and integrates it with auditory input. 

Picture Credit : Google