RESPIRATION AND HAIR

Respiration is frequently confused with the process of breathing. Respiration is in fact concerned with the liberation of energy, which is so vital to the body. Whilst breathing is the process of filling and emptying the lungs to bring air into contact with the blood. Energy is obtained from food which contains complex chemicals, such as glucose. The glucose molecule contains atoms of carbon, hydrogen and oxygen held together by chemical bonds. Energy is required for the formation of these chemical bonds and when broken energy is released.

RESPIRATION IS AN OXIDATION PROCESS, which occurs in a living cell. Oxygen is usually necessary for the process. Oxygen we need to oxidise glucose in the body cells is obtained from the air during breathing. This rhythmic process normally takes place about sixteen to seventeen times a minute. Air is forced through the air passage in the head and so into the lungs by atmospheric pressure when the chest increases in volume. This increase is brought about by the lowering of the diaphragm due to the contractions of the diaphragm muscles and by the upward and outward movement of the ribs due to the contraction of the intercostal muscles between the ribs. The air in the lungs is forced out of the body, when the volume of the chest decreases, due to the relaxation of the diaphragm muscles. So raising the diaphragm and the relaxation of the intercostal muscles which lowers the ribs.

The alternate contraction and relaxation of these muscles is controlled by messages from the brain, sent along nerves to the muscles. The lungs themselves contain a series of finely branching tubes each ending in a small group of air sacs called ALVEOLI. The walls of the air sacs are very thin and are surrounded by a network of fine blood capillaries. It is here that oxygen from the air in the lungs passes through the alveoli walls into the blood. At the same time carbon dioxide, the waste product of the oxidation of glucose in the body cells passes from the bloodstream into the air sacs and breathed out. The exchange of gasses in the lungs is called EXTERNAL RESPIRATION. Thus the air breathed out contains more carbon dioxide and less oxygen than the air breathed.

THE NUTRITION OF HAIR

Healthy growing hair needs nourishment, growth depends on the constant division of the cells surrounding the papillae. The newly formed cells must then change shape and become keratinised as they travel along the hair follicle.

THE MATERIALS REQUIRED FOR THE GROWTH AND DEVELOPMENT OF HEALTHY HAIR ARE BROUGHT TO THE HAIR PAPILLA BY THE BLOOD.

These materials include products of the digestion of the food we eat and the air we breathe in OXYGEN. Concluding that the nourishment of hair involves the respiratory system, the digestive system and the BLOOD SYSTEM.

The materials required for the nutrition of hair are GLUCOSE AND OXYGEN. The dividing cells in the germinal matrix require a supply of energy to enable various chemical reactions to take place, inside the cells. This energy is produced when oxygen from the air we breathe reacts chemically with glucose. This chemical reaction is an oxidation process, since it involves the addition of oxygen to the glucose.

Glucose is a white crystalline monosaccharide sugar that has several optically active forms. The most abundant being dextrose, a major energy source in metabolism. Glucose is obtained mainly from the digestion of carbohydrate foods (sugars and starches), but may also be obtained by the breakdown of fats from any non-essential amino acid.

The process of oxidising the glucose would take place Very slowly if group B vitamins were not present. These vitamins increase the rate of the chemical reaction, Without being changed themselves. Other vitamins and minerals also play a major part in the growth of hair, vitamin A affects the formation of keratin, vitamin C is necessary to make the cementing materials between cells. The mineral element iron is required to form red Cells which Carry oxygen in the blood. Mature hair Consists mainly of the protein keratin, which like other proteins are an essential constituent of all living organisms, is built up from smaller units called amino acids. During digestion, protein foods such as milk, fish, eggs and meat are broken down into amino acids. THESE ARE CIRCULATED IN THE BLOOD STREAM, sorted out and re-arranged to be built up into keratin in the cells of the hair. Thus, the nutrition of hair depends on the food we eat, that must be digested and on the air We breathe. To maintain health We must have a daily supply of proteins (meat, eggs, fish, cheese, peas, beans, soya beans, nuts, vegetable proteins and animal proteins) in order to build new cells e.g. new hair, nails and skin cells, protein may also produce energy. There is very little danger or lack of these in the U.K. diets. A lack can cause stunted growth, blotchy skin, poor thin hair and loss of hair colour. We need Carbohydrates to provide energy, minerals like calcium, which we get from milk or cheese to build strong teeth and bones and stop you from getting rickets. Iron obtained from egg yolk, liver and green vegetables, to build up haemoglobin for red Cells, which carry oxygen, with anaemia resulting in deficiency, vitamin A vital for correct functioning of the retina of the eyes, also prevent keratin from forming in the lining of the nose and throat and on the front of the eyebrows. dairy produce, margarine, liver, carrots and fish contain the essential vitamin which deters blindness, dry nose leading to infection. Keratin plugs in the follicles of the upper arms and legs.

Lack of vitamin B affects nerves, skin and the digestion of food, these are obtained from Cereals, meats, liver, oranges, black currants and green vegetables are full of vitamin C, to build the Cementing material between cells and help with the absorption of iron. l suffered myself from a lack of these while Working at a holiday Camp, after about four months my gums would bleed all the time. Also Causes scurvy, loose teeth, bruising and poor healing of Wounds.
Vitamin D, which is a must to ensure the building of strong teeth and bone, source of this Can be provided by dairy goods, also made in the skin by the action of sunlight. Our bodies are built larger from proteins which are complex substances Comprising long chains of amino acids. Some of these amino acids are made by the body, but others have to be obtained by the breakdown of proteins in our food. It is generally Considered that each day We require one gram of protein food for each kilogram of body Weight. For an average man this means some seventy grams of protein.

THE DIGESTION OF FOOD

Digestion is necessary to break down foods into simple substances, which can be absorbed into the bloodstream. In the mouth food is chewed or masticated, by the action of the jaws and teeth and is mixed with saliva. Mastication renders the food small enough to be swallowed and allows saliva to mix thoroughly with it. The alimentary canal, where digestion takes place, starts at the mouth and ends at the anus. Food in the mouth is swallowed and is then moved through the alimentary canal by the action of the muscles in the wall of the gut. Food is broken down by the churning movement of the stomach.

The main breakdown however, is by chemical action brought about by organic enzymes or catalysts secreted by the walls of the digestive tract itself. Digestion is aided by the liver, pancreas and salivary glands. Each digestive enzyme will only act on one type of nutrient. Pepsin is an enzyme which acts on proteins, breaking long chain molecules into shorter lengths. Renin is an enzyme which acts on soluble protein of milk, a protein which cannot be acted on by pepsin. Digestion begins in the mouth, continues in the stomach and the small intestine and is completed in the lower part of the small intestine, the ileum. The digested food is then absorbed through the walls of the ileum and enters the fine blood vessels, which surround the ileum wall.

The surface area of the inner lining of the small intestine is greatly increased by means of folds bearing tiny projections called Villi, which extend like hairs on a carpet. These projections cover the whole lining, there are over five million of them, which are constantly lengthening, shortening and swaying as they come into contact with digested food.

Within the villi are blood and lymph vessels, into which the product of digestion are absorbed. Simple sugars (glucose, fructose and galactose) from carbohydrate digestion and amino acid digestion pass into the blood system and are passed along the portal vein into the liver. This vital organ controls the food content in the blood. Storing surplus sugar as glycogen and breaking down unwanted amino acids. Blood leaving the liver has a constant composition. Blood carries the products of digestion to the heart, which circulates them to all parts of the body e.g. the Scalp.

The indigestible part of food passes into the large intestine where Water is absorbed. The remainder is passed out of the body through the anus.

THE STRUCTURE OF THE SKIN

The skin consists of two main layers. The epidermis (the outer layer) and the dermis, which is the inner layer. Beneath the dermis is a fatty subcutaneous layer which, in most parts of the body, loosely attach the skin to the underlying muscle. In the scalp however, a strong shaft of fibrous tissue or tendon called Epioranial Aponeurosis lies immediately below the subcutaneous tissue. The boundary between the epidermis and dermis is Clearly defined, buttne dermis merges gradually with the subcutaneous layer, varying amounts of fat stored in the subcutaneous tissue, acts as insulation to prevent loss of body neat. The surface of the skin and hair is coated with the slightly acid secretion of two types of glands.

A) Sweat glands are coiled tubes lying in the dermis with a duct leading to an opening or pore on the surface of the skin. Sweat consists of 98% water and 2% Sodium Chloride (common salt) with traces of many other substances. The liquid sweat takes heat from the body when it evaporates and this Cools the body.

B) Sebaceous glands are small, sacculated and lodged in the substance of the dermis. They are found in most parts of the skin, but especially abundant in the scalp and face.

They open into the hair follicle and secrete an oily substance called Sebum, which lubricates the skin and hair shaft, so helping to make them Waterproof. Sebum gives lustre to the hair, though excess makes the hair greasy. The secretory activity of the sebaceous gland does not appear to be under nervous control. It is stimulated by hormonal action particularly androgen (male hormones).

The skin is Composed of several layers of cells and the lower the layer the more active the cells. The top layer of skin is the final result of the cells activity below. The top layer of skin is called the EPIDERMlS. It is the outer covering of the skin and is divided into several layers. The cells of the top Skin are hard and horny and are arranged in an overlapping manner, known as the HORNY LAYER. There is little elasticity or colour in these cells and the uppermost are in the process of falling from the skin. Flat dead cells of keratin which are gradually shed from the surface of the skin by friction as for example, when scales are removed from the scalp during brushing. When the skin is wrapped in a bandage for a long time, the dead cells may be seen on its removal as white flakes or strips of dead skin. It is the part of the skin, which is constantly being washed, rubbed or worn away.
Below the horny layer is the CLEAR layer. The flattened cells of this layer contain keratin and have no nuclei, melanin granules are destroyed in this layer of colourless cells. Sunlight penetrates through this layer and activates temporary skin colour.
The GRANULAR layer lays beneath the clear layer. It is composed of layers of granulated cells which are softer than the hard cells above. The nuclei of the cells, in this layer are breaking down leading to the death of the cells. Also, keratin are being formed in the Cells. Keratin is a fibrous sulphur containing protein.
The next layer is composed of a mixture of cell types and is known by several names, the most common being the PRICKLE CELL LAYER. In the lower parts of this layer are found the cells which Contain the natural Colour pigment. Some of the soft nucleated cells of this layer have a spiny outgrowth through which it is thought that melanin granules enter the cells.

Together with the germinating layer it forms the living part of the epidermis. The GERMINATING LAYER is the lowest part of the epidermis. It is sometimes called the base layer. This is formed of larger cells which line the wavy base of the epidermis. This actively growing layer consists of regularly arranged cells which are Constantly dividing to form new Cells, so pushing the old Cells towards the surface of the skin. The germinating layer is continuous around the hair follicles, sebaceous glands and sweat glands, and although these structures may appear to be part of the dermis they are all down growths of the epidermis. Among the cells of this layer are smaller cells called melanocytes. Which produce the pigment of the skin, in the form of black, brown or yellow granules of melanin. Sunbathing increases the production of melanin which protects the skin from damage by the sun’s rays. The dark pigment absorbs harmful radiation. There is no blood or nerve supply to the epidermis, all nutrients come from below.

The DERMIS joins the epidermis in a series of ridges called dermal papillae, which are shallow in the scalp. The dermis is the largest section of the skin, and is abundantly supplied with blood and nerve vessels which take nourishment to the growing cells of the epidermis. The blood vessels also help to keep the body temperature constant, by dilating if the body is too not and constricting if the body is too cold. It also contains units of touch, heat, cold and pain in its upper regions. The dermis is between 1 mm and 4mm in thickness and consists of a dense network of fibres embedded in a jelly like ground substance. Many of the fibres are elastic fibres and give the skin flexibility the ground substance holds a lot of water which makes the skin firm.

Underlying the dermis is the subcutaneous tissue. This is a compound of loose cellular and fatty tissue. This part of the skin stores fat, and gives firmness and roundness to the body’s shapes. It assists in temperature regulation and acts as a protective cushion.

In an unborn child the formation of the hair in the skin initially takes place by a down growth of the epidermis and an upgrowth from the area which is to become the papillae and the germinal matrix the outside of the follicle being a continuation of tine germinating layer of the epidermis. The walls of the follicle are known as the outer root sheath. The dermis forms a protective sheath of connective tissue round each follicle and also projects upwards at the base of the follicle forming the hair papilla.

The hair grows from the epidermal cells surrounding the papilla. The Cells are being nourished from the blood vessels which enter the papilla. Each hair follicle has a muscle, Called the arrector pili muscle. In certain conditions, cold or fear cause the muscle to contract. Moving the sloping follicle and making the hair stand erect, long hair will not appear to stand on end. This muscle contraction is an attempt by the body to trap a layer of still air between the skin and hair to prevent heat loss. Whilst in the follicle, the hair itself is surrounded and protected by the inner root sheath, which grows alongside the hair. The inner root sheath Consists of three layers.

(A) A Cuticle with overlapping scales pointing to the base of the follicle and so over-locking with the Cuticle of the hair and holding the hair firmly.
(B) HUXLEY’S layer, two or three Cells in thickness.
(C) HENLE’S layer, of one cell in thickness which lies next to, but separate from the outer root sheath


The surface of Henle’s layer is smooth and easily able to slip over the outer sheath, as the hair and its inner root sheath move upwards together. The inner root sheath breaks down about two thirds of the Way up the follicle at the level of the opening of the sebaceous glands, the passage of hair along the remaining part of the follicle is eased by the presence of Sebum. If a hair is pulled from the scalp the inner root sheath Comes out at the same time and can be seen as a White thickening at the end of the hair. The lower part of the follicle widens out into the hair bulb which fits over the papilla. The epidermal cells surrounding the papilla form the germinal matrix of the root of hair. These cells are constantly dividing to make new cells which push the older ones upwards.

At first all the cells are alike, but as they move up the follicle they begin to change shape and keratin develops in the cells. The different types of cell for cuticle, cortex and medulla of the hair and the cells of the inner root sheath develop. By the time they are about one third of the way up the follicle cells are dead and fully keratinised. Between the cells surrounding the papilla are melanocytes producing melanin, the Colour of the hair, most of which passes into the cortex of the hair.

“The Story of Hair”

Hair grows almost everywhere on the body. The hair l think you really want to know about is the hair that grows out of the scalp. Wherever it is found, the structure and growth cycle of all human hair is the same.

Hair consists of a shaft, the portion visible to the outside world. The shaft is always pointed unless it has been trimmed. But the story of hair really begins below the skin’s surface. Where each hair is contained within a pouch-like tube called a Follicle. The portion projecting out of the surface of the skin with a funnel shaped opening and passes inwards in a curved or slanted direction, the latter in curly hair, to become dilated at its deepest extremity where it corresponds with the root. The ducts of one or more sebaceous glands open into the follicle near the skin’s surface.

At the bottom of each follicle is the root, the oval shaped centre where hair growth actually begins. Jutting into the bottom of the root is the papilla, it’s continuous with the dermal layer of the root, and is supplied with myelinated and nonrnyelinated nerve endings. The papilla contains the vital capillaries linking the body’s blood supply to each growing strand of hair.

The shaft is made up of dead, strong, durable material called keratin. The active growing part of hair, which is still alive is situated at the base of the root about 4mm deep and 0.4mm wide. Overleaf is a diagram of hair.

Therefore, the hair dies as it grows up the follicle, becomes hardened and emerges from the skin’s surface as dead material known as keratin.