The cerebrum is split down the middle into two halves called hemispheres that communicate with each other.
Cerebellum
Your cerebellum is the second largest part of your brain. It is involved in coordinating your muscles to allow accurate movements and control of balance and posture.
Diencephalon
Your diencephalon sits beneath the middle of your cerebrum and on top of your brain stem. It includes two important structures called the thalamus and the hypothalamus. Your thalamus receives incoming sensory nerve impulses, and then sends them on to appropriate areas of your brain for processing. It is responsible for informing your brain what's occurring outside of your body.
Your hypothalamus plays a vital role in keeping conditions inside your body constant e.g. regulating your body temperature; thirst and hunger. It also controls the release of hormones from the pituitary gland.
Brain stem
Your brain stem is responsible for regulating many life support mechanisms e.g. heart rate, blood pressure, digestion and breathing. It also regulates when you sleep and wake.
Brain protection
Your brain is certainly your most important organ, but it is made of soft tissues that would be injured by the slightest pressure. It is therefore well protected by three tough membranes called meninges which surround your brain.
The space between your brain and the meninges is filled with a clear fluid; cerebrospinal fluid, which cushions your brain; it also provides it with energy and protects it against infection. Your skull encases your brain in a bony shell, cerebrospinal fluid and meninges.
Long-term or excessive drinking can and does cause damage to the brain - Neurological damage and memory loss. Some damage can repair itself, but some can become permanent. Heavy drinking causes physical brain damage and even alcohol-induced dementia. This occurs when the impulses are not responding properly due to lack of oxygen and excess alcohol. Shrinkage of the brain is caused by excessive alcohol; this affects the cortex of the frontal lobe, which is believed to be the seat of higher intellectual functions.
Spinal Cord:
Your spinal cord can be divided into four sections shown in green, blue, pink and turquoise (see figure 4). Nerves emerging from these sections serve different parts of your body.
The effect of Alcohol:
Alcohol is a depressant drug (Sedative-Hypnotics). Depressants are habit forming drugs which can lead to severe addiction problems. Among the most abused depressant drugs is Alcohol.
Alcohol is used to relax the nervous system. One of the most rapid affects of alcohol is on the central nervous system (CNS), which controls a range of vital body functions; the sense organs, muscles controlling speech as well as the sweat glands in the skin. The nerves which leave the spinal cord and brain comprise the peripheral nervous system. Your peripheral nervous system consists of 12 pairs of cranial nerves (see figure 5), which emerge from your brain and mainly serve your head and neck. It also contains 31 pairs of spinal nerves (see figure 6), which branch off from your spinal cord and supply the rest of your body.
In normal circumstances the CNS receives sensory information from organs such as the eyes and ears, it analyses the information and then initiates an appropriate response e.g. contracting a muscle.
But when alcohol (toxins) interfere the CNS’s ability to analyse sensory information resulting in the typical symptoms of being drunk such as disturbed balance, slurred speech, blurred vision, heavy sweating and the dulling of our sensation of pain, and even loss of consciousness and possibly death.
Peripheral nervous system
Your spinal cord has 31 pairs of nerves, (see figure 5)
How it works:
When you drink alcohol it is absorbed into the bloodstream from the stomach and small intestine. Once in the blood it is rapidly dispersed throughout the body and begins to have an effect on every cell. Alcohol is a cell poison but the body is efficient at protecting itself from most of its dangerous effects. It does so by chemical reactions which take place in the liver. As the blood passes through the liver the alcohol is gradually broken down to less harmful substances. Alcohol affects the brain, heart, muscles and other tissues of the body. (See Figure 7). In particular it reaches the brain quickly and therefore acts as a depressant.
Alcohol causes low blood pressure. Blood vessels are open (vasodilation - an increase reduction in the diameter of small arteries (arterioles) which is caused by relaxation of the smooth muscle fibres in the wall of the arteriole), it is therefore easier for blood to flow through your body – low peripheral resistence (causing flushing) – low blood pressure
Blood is transported around the circulatory system, it reaches the vena cava where it builds up, because your heart is beating slowly the pressure to pump the blood through is low, this then causes the vena cava to stretch (stretch receptor), impulses are then sent to your brain (acceleratory centre which is located in Medulla Oblongata), which in turn sends a message back to S. A. Node (in your heart) to speed up, which enables the blood in the vena cava to start flowing again.
Alcohol and Your Kidneys:
The kidneys (see figure 8) direct fluids straight to the bladder, making you urinate excessively and speeding up the loss of fluid from the body causing dehydration. Most of the symptoms of a hangover include: headaches, dizziness, thirst, paleness and tremors, these are all caused by dehydration.
Alcohol and Your Liver:
The liver plays a vital role in the human body. It fights infection and filters poison. It also maintains our normal body chemistry
It metabolises about 90% of the alcohol in our body while only about 10% is excreted through either our urine or our breath. The rate of alcohol metabolising varies between males and females. The alcohol metabolises at the rate of one – two units per hour.
A unit of alcohol is equivalent to half a pint of beer or lager, 25mls (a standard shot) of spirits in a pub or 125mls of red or white wine.
When a person drinks, the body responds to large quantities of increased glucose in the system by producing more insulin which removes the glucose; this is known as Hypoglycaemia.
Once the process has started, the insulin carries on working removing glucose from the blood. Hypoglycaemia is responsible for the shaky feeling, heavy sweating, dizziness and blurred vision. Low glucose levels also result in feeling tired.
To overcome this feeling of lethargy and tiredness the body craves a carbohydrate boost; which is why many people feel hungry when they have been drinking.
Long term alcohol exposure has a very serious effect on the liver. It starts producing more alcohol dehydrogenase, an alcohol + NAD+ = an aldehyde or ketone (see figure 9) + NADH + H+, the enzyme which is used to break ethanol down.
This means, you need to consume more alcohol to be able to get the same effect. This worsens the addiction. The liver then becomes over active, cells die and the tissue hardens. The result is cirrhosis of the liver.
Conclusion:
Ethyl alcohol (ethanol, CH3CH2OH,) is a low molecular weight aliphatic (open chain) compound, which is completely soluble with water. This is because of its hydroxyl (-OH) group, which forms intermolecular hydrogen bonds to water. The hydroxyl group is hydrophilic (water-attracting), whereas the ethyl (C2H5-) group is hydrophobic (water-repelling).
Because alcohol is soluble with water, it is easily distributed throughout the body in the aqueous blood stream after consumption; and because it is water soluble, it can easily cross important biological membranes such as the blood brain barrier, which in turn affects a large number of organs and biological processes in the body.
The passage of ethyl alcohol across biological membranes occurs by a process of simple passive diffusion along concentration gradients.
This would therefore conclude, that alcohol can be a very harmful substance, which can affect various organs and also damage the blood stream, which also enables the organs to deterioate more rapidy.
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