Endothelial Cells

Life Enhancing Functions of the Endothelial Cells!

How and When to Be Your Own Doctor
You should be able to understand simple word equations but no chemical symbol equations are required. Who is offered amniocentesis? It was time for him to go home before I lost my good humor. When the two auricles are full of blood, they contract simultaneously. The intestines and stomach are found in the abdominopelvic cavity [top].


NCERT Solutions for Class 10th: Ch 6 Life Processes Science

If your gestation is greater than 13 weeks 6 days of pregnancy, other screening tests are available in your second trimester of pregnancy. You may wish to discuss these tests further with your referring doctor or genetic counsellor. Where can I find out more information about these tests? Please feel free to contact one of our clinics. A pelvic ultrasound assesses the female reproductive system, including the vagina, cervix, uterus, fallopian tubes, ovaries and other pelvic structures.

It can provide helpful information for those experiencing. How is the examination performed? Transvaginal ultrasound is performed using a special transducer which is slightly thicker than a tampon. It is covered with a disposable latex sheath and lubricating gel, then gently placed into the vagina.

The probe sits in the vagina throughout the examination which usually takes between minutes. Most patients find the examination much more tolerable when compared to a cervical PAP smear.

During the scan the sonographer may need to gently press on the abdomen to move bowel out of the way and bring the ovaries and other pelvic structures into view. This also enables any point of tenderness in the pelvis to be identified. Transvaginal or transabdominal ultrasound: Is there a choice?

It is a Sydney Ultrasound For Women protocol to offer transvaginal assessment for all Gynaecological and early pregnancy scans. This is because the transducer is positioned close to the pelvic structures, producing superior image quality, hence, the most detailed and accurate diagnosis. Though a SUFW protocol to offer an internal scan, patients may decline and instead be scanned transabdominally. In certain circumstances a transvaginal ultrasound examination is not possible or not advisable eg.

A full bladder transabdominal ultrasound will then be performed. What are the preparations I should take before the ultrasound examination? The transvaginal examination is best performed with an empty bladder.

Upon arrival at the clinic, those booked for gynaecological or early pregnancy scans will be asked to empty their bladder. It is important that a tampon be removed prior to the examination. If you are bleeding at the time of examination the scan can still be performed. Bleeding does not affect the ability to diagnose.

Patients are draped during the examination and are given privacy when dressing. If an abdominal ultrasound is preferred, a moderately full bladder is necessary. To this effect, patients should drink 3 glasses of water one hour before the appointment time and not empty the bladder until after the scan.

Why scan at 7 weeks? Prior to 7 weeks it may be too early to acquire this information. How is the scan performed? To obtain to best images possible, this scan is routinely performed transvaginally.

This examination is safe to perform during early pregnancy. What will I see on the ultrasound? At 7 weeks gestation a pregnancy sac should be seen within the uterus. Within this sac an embryo, heart motion and yolk sac should be visible.

Approaching 8 weeks, early brain formation is identified with a black space in the head called the rhombencephalon. In this situation you may be required to return for a repeat ultrasound in days. Your doctor will inform you of the most appropriate time frame to return for this scan if required. Routine 7 week IVF pregnancy ultrasound If you have completed an IVF cycle and have received a positive pregnancy result at day 16, a trans-vaginal ultrasound will be performed approximately 5 weeks following embryo transfer.

This ultrasound will confirm the location of pregnancy and the number, size and heart motion of the embryo s. Regardless of the scans you may have had previously, the week scan is important as it provides information about your pregnancy that has not been provided before. Sydney Ultrasound For Women protocol is to perform a transvaginal ultrasound at the week scan.

In the majority of cases, this provides superior image quality and therefore finely detailed assessment of the fetus. What is the risk of the scan? Both transvaginal and transabdominal ultrasound examinations are safe throughout pregnancy. In the state of Victoria a routine ultrasound examination is offered to most patients at 20 weeks.

The purpose of this examination is to assess the: This examination is expected to detect the majority of major fetal malformations. It is important to appreciate, however, that such an examination does not detect all abnormalities. Some congenital heart abnormalities are progressive and unable to be detected at the 20 week ultrasound. Cerebral palsy, biochemical abnormalities and some chromosomal abnormalities cannot be detected. This study is often limited due to the fetus being much larger, with a relative decrease in surrounding amniotic fluid.

This makes imaging more challenging for the clinician. Menstrual bleeding usually occurs every 28 days, although each cycle is different and some may be longer or shorter. At times the cycle may be irregular or bleeding may become heavy. This may be due to a temporary hormonal imbalance but it may also signal a problem in the uterus or ovaries such as:.

Pain may be caused by any organ in the abdomen, and as such is often difficult to determine an exact cause without ultrasound. Common conditions detected through ultrasound include:. Symptoms from ovarian cancer tend to occur quite late in the disease when it is increasingly difficult to treat.

Ultrasound can play a significant role in the detection or exclusion of ovarian cancer through colour doppler ultrasound. The examination will help identify if the ovaries are enlarged or if new blood vessels have appeared to supply a growing tumour. Regular screening is recommended for those at increased risk:. Sonohysterography is a new technique developed to better image the uterine cavity.

It uses an infusion of sterile saline through a soft plastic catheter placed in the cervix in conjunction with transvaginal ultrasound. The saline infusion distends the uterine cavity and provides an excellent contrast to the lining, giving improved visualisation of uterine and endometrial pathology.

This technique may also be used to assess the fallopian tubes by demonstrating fluid spill into the pelvis. Colour Doppler imaging demonstrates the movement of ultrasound contrast medium within the tube.

Is there any discomfort? There can be discomfort associated with this procedure especially if the patient suffers from dysmenorrhoea. Taking an analgesic such as Naprogesic two tablets half an hour before the procedure is recommended. Should the patient suffer from dysmenorrhoea it is advised that driving is not recommneded after the procedure and alternate arrangements should be made to travel home.

The procedure This is a simple procedure, able to be performed in the ultrasound room. It allows the presence, nature, size, vascularity and site of attachment of a mass in the uterine cavity to be assessed before definitive surgery.

In a number of cases, it can eliminate the need for further investigation when no significant endometrial pathology can be demonstrated.

This is particularly important in cases of bleeding around the time of menopause where a hormonal disturbance is the most common cause and does not benefit from surgery. Patients undergoing investigation for infertility have a high incidence of polyps in the uterine cavity which may be responsible for their inability to conceive. This is particularly important in those patients starting on IVF programmes, as these polyps may limit their success.

Patients on long term Tamoxifen therapy for breast cancer, have been shown to develop polyps and thickened uterine linings endometrial hyperplasia as well as occassionally developing endometrial cancer. Although this is a rare complication, it is an important side effect of Tamoxifen. More commonly, however there changes in the muscular layer just under the uterine lining which is distinguishable from endometrial hyperplasia on sonohysterography but not on standard transvaginal ultrasound.

HyCoSy is increasingly used as a first line investigation for infertility because of its convenience and safety in examining the fallopian tubes and other pelvic organs. It provides a low-risk, outpatient procedure providing a direction for further diagnosis and treatment of infertility. Management of tubal disease The management of tubal Fallopian disease as a cause of infertility has changed dramatically in recent years.

This is largely due to the rapidly improving results of assisted conception through in-vitro fertilisation IVF compared to the disappointing results achieved through tubal microsurgery.

The function of the Fallopian tube The ovary produces the egg and it needs to meet the sperm if pregnancy is to eventuate. After fertilisation occurs, the embryo must progress to the uterine cavity, where it implants. If the tube is blocked, then the egg and sperm will not meet. If the embryo, after fertilisation, does not pass through the tube at the normal rate, then it can implant in the Fallopian tube.

This is called an ectopic pregnancy. HyCoSy explained Hysterosalpingo-contrast-sonography HyCoSy is a transvaginal ultrasound technique in which a saline solution is infused into the uterine cavity and observed to flow along the Fallopian tubes to assess tubal patency.

The bright echoes generated by the saline solution makes tubal visualisation easier, which is further improved by the addition of colour Doppler imaging. There can be mild discomfort associated with this procedure, particularly if the Fallopian tubes are blocked. Pain relief will be discussed at the time of the procedure by our medical staff. Follicle tracking involves tracking the development of egg-containing follicles within the ovary from an immature state primordial follicles to a mature state leading or dominant follicles.

This process is monitored with transvaginal ultrasound in combination with blood levels of the female hormones oestrogen and progesterone. Tracking for timed intercourse: Follicles may be tracked in a natural cycle.

When a leading follicle is seen average size 22mm , with a range of mm then intercourse may be appropriately timed. Alternatively, drugs which promote release of the mature egg luteinising hormone may be administered.

For most IVF treatments, the ovaries are artificially stimulated with follicle stimulating hormone FSH which produces multiple mature follicles which are then harvested following administration of luteinising hormone LH. In this setting, the follicular development is followed more closely with 2 to 4 ultrasound scans, and regular blood sampling tracks hormone levels.

The timing of an egg collection is based on the ultrasound and blood results. This information is relayed to patients by their IVF nurse or clinician. Egg collection is performed as a transvaginal ultrasound guided procedure under anaesthetic. However, in some patients where there is difficulty achieving vaginal access, egg collection may be performed transabdominally. Please provide a referral and any previous pelvic ultrasound reports.

What are polycystic ovaries PCO? PCO are ovaries which contain an excessive number of primordial follicles. Primordial follicles are tiny fluid filled sacs which contain the eggs. An ultrasound of the ovaries during the reproductive years usually shows on average follicles in each ovary. What is the cause of polycystic ovaries PCO?

In a normal menstrual cycle there are usually follicles at the beginning of the cycle. Later in the cycle, usually around day 14, one follicle gets bigger leading follicle and shortly thereafter ovulation takes place with release of the egg. The remaining follicles regress and disappear before the next cycle. These events are usually after every 4 weeks and result in the monthly menstrual bleed.

In women with PCO, not all of the follicles regress each cycle and therefore there is an increase in number with successive cycles. Despite extensive research no single cause explains this variation from normal. Polycystic ovaries vs polycystic ovarian syndrome Polycystic ovaries should not be confused with polycystic ovarian syndrome PCOS.

PCOS is a condition that results from a disturbance of blood hormones, and may present with weight gain, acne, irregular or infrequent periods, and excess hair growth. What causes polycystic ovarian syndrome PCOS? In women with PCOS, an increase in androgen hormone levels disrupts the normal cyclical sequence of events within the ovary. Instead, no leading egg develops and ovulation does not occur. There is a build up of small immature follicles over time and symptoms listed above may become apparent.

This is not a serious condition. In fact the vast majority of patients do not require any form of treatment. If, however, you are having difficulty getting pregnant or having menstrual problems there is a wide range of treatment options and most have high success rates.

These may be discussed fully with your family doctor or specialist. A fibroid is a benign growth of fibrous muscle tissue which develops in the wall of the uterus. To experience the mechanical quality of loose connective tissue, try the following. See how far the two surfaces can move relative to one another. The freedom is due to the looseness of the intervening connective tissue. The limits are set by the collagen fibers which become straightened until taut.

Examples of loose connective tissue include hypodermis , lamina propria , submucosa , mesentery , and fascia. The textbook "ideal" example of ordinary loose connective tissue is sometimes called areolar tissue areolar refers to the small spaces filled with ground substance.

Dense connective tissue may be further described as either regular or irregular , depending on the orientation of the fibers. In regular connective tissue example: In irregular connective tissue example: Fibrocollagenous or just fibrous tissue contains a substantial proportion of collagen. A principal feature of fibrous tissue is flexibility combined with great tensile strength.

Because collagen is colorless and typically scatters light, fibrous connective tissue usually appears white. The sclera or "white" of the eye is a readily visible example of dense fibrous connective tissue comprising an organ sheath. Tendons and muscle capsule may also be familiar from the butcher shop or anatomy lab. The ends of muscle fibers are typically attached to dense fibrous connective tissue of periosteum, tendon, or ligament.

The dermis of the skin is also fibrous connective tissue hence, leather is mostly collagen. Elastic tissue is a dense connective tissue which contains predominantly elastic fibers rather than collagen.

It is more elastic obviously than dense collagenous connective tissue. Adipose tissue is loose connective tissue which is dominated by fat cells , or adipocytes. Since most loose connective tissue contains scattered clusters of adipocytes , the term adipose tissue is usually reserved for large masses grossly visible of these cells.

Lymphoid tissue is loose connective tissue with large numbers of lymphocytes that have accumulated in the tissue. Lamina propria the loose connective tissue of mucosal surfaces often shows lymphatic tendencies, or even fairly well-developed lymph nodules.

The immune cells in these locations form a vital second line of defense the epithelium with its continuous but rather easily broken wall was the first line against invading microorganisms.

A separate page describes the lymphatic system , including lymphoid tissues in several specialized lymphoid organs -- spleen , thymus , lymph nodes , and tonsils. Lymphoid organs are also sometimes called reticular tissue because of the supporting framework of reticular fibers a delicate, branching form of collagen. For more on lymphoid tissue, visit " Lymphoid Tissues "at Blue Histology.

The ideally generalized form of connective tissue, with unspecialized proportions of the various matrix components and cells, receives its own name: Mesentery is usually given as the standard example. Areolar tissue is often introduced with a whole-mount preparation of mesentery. The term "areolar" refers to the many small spaces filled with ground substance visible in this tissue.

Blood is traditionally classified as a specialized form of connective tissue, with no fibers, highly fluid ground substance, and mobile cells. Blood is thus distinct from ordinary connective tissue. However, blood may also be usefully regarded as simply a fraction of ordinary connective tissue that is free to gallop around from place to place along differentiated highways.

Follow the links for a more extensive discussion of blood. Only the red blood cells , like trolley cars, are confined to the highways i. All other cell types in blood, and most plasma constituents as well, can circulate rather freely from blood to connective tissue and back again. Thus, most of the mobile cellular components of ordinary connective tissue are interchangeable with those in blood.

Cell names may differ between blood and ordinary connective tissue. The cells which are called macrophages in ordinary connective tissue are called monocytes in blood.

Blood cells similar to tissue mast cells are called basophils. From this point of view, the term " white blood cell " is not only very nonspecific but is also a misnomer. Bone and cartilage are special forms of connective tissue, made by specialized osteoblasts and chondroblasts, with uniquely solidified ground substance. These forms are described on a separate page, as skeletal tissue.

After injury, connective tissue is instrumental in tissue repair , specifically in scar formation. The circulatory system is the familiar mechanism for moving materials around the body. However, blood vessels do not go quite far enough. Most cells are not situated directly against capillaries, but rather some tens or even hundreds of micrometers several cell diameters away from the nearest blood vessel.

Connective tissue more specifically the stabilized water in the ground substance provides the final pathway for diffusion of nutrients, oxygen, waste and metabolites to and from the cells of the body. Subcutaneous and intramuscular injection of drugs also makes use of connective tissue as the initial transport medium. All blood vessels are embedded in connective tissue. The only cells which receive their sustenance directly from the blood are the endothelial cells lining the vessels themselves.

All other cells are supplied via diffusion through intermediary connective tissue. The transport functions of blood and connective tissue cannot be separated.

In essence, blood is really just a mobile fraction of connective tissue. The heart and circulatory system simply facilitate the movement of this traveling tissue. Whenever you find an elaborate capillary bed closely associated with a group of cells such as the capillary network enveloping skeletal muscle fibers or encircling secretory acini , you can predict that these cells must have some exceptionally high demand for transport in or out, since a resting cell can live quite happily at some distance from the nearest blood supply.

Rich capillary supply is characteristic of muscle and brain supplying oxygen , lung acquiring oxygen , intestinal villi collecting nutrients , exocrine glands delivering raw materials for secretion , and endocrine glands collecting hormones. Connective tissue serves as a transportation route not only for the body's normal economy but also for invading microorganisms. To provide defense against this eventuality, an army of various cell types are deployed throughout the connective tissue.

Connective tissue forms the principal battleground for invasions: Bacteria do not easily proliferate within epithelia --cell membranes block entry into cells, and there is little extracellular food for bacteria within epithelia.

On the other hand, connective tissue offers a potential paradise. The abundant extracellular material provides all the necessary nutrients as well as an ideal warm, humid, oxygenated environment. Without vigorous immunological defenses within the connective tissue, any small break in the epithelium would convert the body into an excellent bacterial culture. Inflammation is a specific function of connective tissue. Ordinary connective tissue includes two resident cell types with immunological function, mast cells and macrophages.

Resident cells , which essentially remain fixed in place waiting for action, are distinguished from wandering or immigrant cells which migrate in and out of the tissue. They are very fragile, rupturing at any disturbance. The release of their granules stored secretory product triggers a number of physiological defense mechanisms, including inflammation. Monocytes, which are circulating cells in the blood, differentiate into macrophages when they enter connective tissue.

But when an invasion requires reinforcements, monocytes can increase the macrophage population many-fold. Other fixed cells i. Wandering connective tissue cells , also called white blood cells , travel in and out of connective tissue. Five basic types may be considered:. The distribution of the wandering immune cells reflects ongoing physiological and pathological processes.

The mechanical quality of most ordinary connective tissue is affected only indirectly by the cells which occur within it unlike epithelial tissue , which consists entirely of cells. An exception is adipose tissue , where the sheer bulk of many adipocytes can offer mechanical protection by cushioning impact.

The major determinant of the mechanical properties of most connective tissue is the extracellular matrix which is secreted by the cells within it fibroblasts in ordinary connective tissue, osteoblasts and chondroblasts in bone and cartilage respectively. In ordinary connective tissue, the ground substance is too fluid to provide much strength.

The jelly-like ground substance of ordinary connective tissue serves mainly to prevent extracellular water from pooling in the lowest part of your body.

But ground substance can be a major structural feature in special forms such as cartilage and bone. In most connective tissue, extracellular fibers form the main structural elements.

Collagen offers flexibility with high tensile strength. Densely packed collagen fibers provide strength with resistance to tearing and stretching.

Loosely packed collagen fibers allow free movement within definite limits. Reticular fibers really, a special form of collagen provide a delicate supporting framework for individual cells, especially when such cells accumulate en masse to form a large solid organ such as the spleen or the liver. Elastin , as the name suggests, is stretchy like rubber bands, helping restore normal shape after distortion. In elastic ligaments and arteries dense elastic fiber concentrations convey strong elastic properties while a lesser concentration of collagen serves simply as a mechanical stop to prevent over-stretching under severe stress.

The most common fixed cell of ordinary connective tissue proper is the fibroblast. Fibroblasts are normally quiescent in the adult. During growth and also during repair after injury fibroblasts are active secretory cells which manufactures the fibers and ground substance of connective tissue. They also retain the ability to multiply when necessary, as during wound healing, and possibly to differentiate into other mesenchymally derived cell types such as vascular endothelium and smooth muscle.

Myofibroblasts resemble fibroblasts but have an additional contractile ability, useful for example for closing wounds. A scar is collagen deposited by fibroblasts during repair. WebPath illustrates scar formation. According to recent research PLoS Genetics , genetically differentiated fibroblasts may also be responsible for guiding localized patterns of tissue organization during growth and repair.

Connective tissue is involved in several interrelated ways with energy storage and thermoregulation. The burden of reserve energy storage falls almost entirely on adipocytes. Many other cells, especially muscle cells, have short-term energy stores in the form of intracellular glycogen.

A larger, but still comparatively small, energy reserve is also provided by glycogen in hepatocytes the epithelial cells of liver. This is because the fright you got caused the brain to send electrical impulses to the adrenal glands making them secrete adrenaline hormone in your bloodstream.

Adrenaline is a hormone that is secreted from the adrenal glands to prepare the body for situations that need lots of energy and fast reflex action, like fights or running away for example. This is why adrenaline is called the three Fs hormone Fight, fright, flight. When adrenaline reaches the heart it causes the cardiac muscle to contract and relax much rapider so that oxygen and glucose reach the muscles of the body faster.

Adrenaline also makes the liver convert glycogen into glucose and secret it in the blood to be used in respiration. When adrenaline reaches the diaphragm and the intercostals muscles of the ribs, they make it contract and relax faster too to increase rate of breathing.

These changes cause an increase in the respiration rate so that lots of energy is being released. Generally, adrenaline is secreted when you are nervous or anxious.

Technologies and science have advanced enough that we can now gut much more money out of farming and animal keeping. Hormones are now being used in farms to increase milk yields in cows and growth rate in cattle and fish. BST is a hormone that is naturally produced in cows. The function of BST is to produce milk. Injecting cows with extra BST will boost milk production and bring in more money for the farmers.

Some people however are against the use of BST and claim it is safer for both the cows and the consumer to keep it natural and keep more cows if we want an increased milk yield. Growth hormones are also being mixed with the food fed to cattle to increase their growth rate and make them grow larger.

But again many people are against this and prefer buying meat and fish that were naturally grown. Nervous System Endocrine System Information sent in form of electrical impulses Information sent in form of chemical hormones Information travel neurones Information travel in bloodstream Information travels extremely rapidly Information travels relatively slow Information is headed to one target effector Information may be used by several targeted organs Electrical signals have an effect that ends quickly Hormones have a longer lasting effect.

Plants cannot move themselves to areas of preferable conditions. This is why plants have the ability to detect a stimulus and respond to it by growing or bending in its direction or away from it. These responses are called tropisms. For example a plant tends to grow its stem in the direction of sunlight for more photosynthesis, this is a tropism.

A tropism can be either positive or negative. If a tropism is in the direction of the stimulus, it is positive. If the tropism is away from the stimulus it is negative. However, positive phototropism can also be described as negative geotropism because it involves the plant growing in the direction opposite to gravity.

And negative photo tropism can be described as positive geotropism because it involves the plant growing towards gravity. Auxin is a plant hormone. It is produced by cells at the tip of roots and shoots of plants. At the tip of a shoot, there is an area in which cells are being produced by dividing so that the shoot grows.

Old cells do not divide, but they grow longer instead. The growth of these cells longer is controlled by auxins. Auxins accumulating there makes the cells on the left side grow much faster than the cells on the right side. When the left side of the shoot starts growing faster than the right side, the shoot will start to bend to the right side towards sunlight.

Auxins tend to settle at the bottom end of the root. However, this does not make the sells of the tip of the root grow longer. Instead, auxins prevent the cells at the bottom tip of the root from growing, making the cells at the middle of the root grow faster.

When the cells of the middle of the root grow faster, they push the root deeper into the soil and the root gets longer. The root grows in the direction of the gravitational pull. Roots show positive geotropism and negative phototropism because they grow towards gravity and away from sunlight at the same time. Shoots show positive phototropism and negative geotropism because they grow towards the sunlight and away from gravity at the same time.

Auxins can be used to kill weeds that grow over grass or cereal crops. If weed grows on crops, auxins are sprayed everywhere. Weeds absorb auxins faster than crops or grass. Auxins accumulate in the weeds making them grow very rapidly. Fast growth of weed kills it leaving the crops or grass alive. Auxins are used ass selective weed killers. Posted by Hamza Afzal at Abdullah Rehman 3 October at Agnes Chikuni 9 January at Katherine Chan 15 June at Nazir 3 September at SM Ghazi 21 January at Ferenkeh Jalloh 16 February at Navin Koolash 22 February at Unknown 14 March at Unknown 13 April at Sydney Tutalife 3 June at Wulan Aura 19 October at Hamza Malhi 13 December at Unknown 13 December at Zakir Mohamed 5 March at Augustine Raja 5 March at Alecia Madonado 16 May at Unknown 29 May at Jissa 6 April at Lara Oakie 19 May at Unknown 6 July at Enzymes are proteins that function as a biological catalyst.

They are proteins in nature. Hydrogen peroxide H2O2 is a substance that decomposes into Water H2O and Oxygen O2 if it is left in room temperature for a period of time.

This reaction could a long time, but it could be sped up if we add a catalyst. Each catalyst can catalyse a specific substance and nothing but it. The catalyst for Hydrogen peroxide is called Manganese4 oxide. If it is added we will get water and oxygen gas in a very short time, and the manganese4 oxide could be obtained again as it was, it remains unchanged.

Washing powders contain detergents that help in cleaning clothes by dissolving stains in water. Some stains are made of insoluble substance, these cannot be removed by normal washing powders, instead, a biological washing powder is used.

Biological washing powders contain enzymes that break down the insoluble stain into smaller soluble substances, which are then dissolved in the water. For example, if your shirt gets stained by egg yolk or blood, there is an enzyme called protease in the washing powder that will break down the insoluble protein into amino acids, which are dissolved in the water and sucked away. Thus the shirt becomes clean. Baking — Brewing — Cheese Making: In baking, both yeast and sugar are used.

Yeast cells contain enzymes that ferment sugar by anaerobic respiration producing carbon dioxide bubbles which causes the dough to rise as in the photo. Brewing is the process of making wine or beer. In this process fermentation is Involved producing alcohol which and carbon dioxide that gives wine and beer its sparkle.

In making cheese, an enzyme called rennin extracted in enzymes, helps by clotting milk. An enzyme called pectinase digests pectin making it much easier to squeeze the fruit and to make the juice more clear than cloudy. Every Individual needs to take in a certain amount of each nutrient daily, depending on their age, size, sex and activity. There are 7 Types of nutrients, these are: Each molecule consists of two Monosaccharide joined together Water soluble Examples: Each molecule has many joined monosaccharide forming a long chain.

Insoluble in water Examples: Bread-Potatoes-Pasta, Cellulose in plant cells and Glycogen in livers. These are organic, soluble substances that should be present in small amount in our diets, they are very important though. Most of the amount of vitamins in our bodies was taken in as nutrients, the body its self can only make few Vitamins, so we have to have to get them from organisms that make them, such as plants.

Each type of Vitamin helps in chemical reactions that take place in our cells. This is present in most fruits and vegetables specially citrus fruits like lemon and oranges, however, it is damaged by heating so it these foods have no value of Vitamin. C if they are eaten cooked. Vitamin C is essential for the formation of Collagen, a protein that functions as cementing layer between cells, Vitamin C also increases immunity.

This is present in fish oils, egg yolk, milk and liver. Unlike Vitamin C, Vitamin D is made by animals as well as plants, this occurs when the skin is exposed to the Ultra Violet Rays of the sun. Vitamin D plays a big role in absorbing Calcium from the small intestine and depositing it in bones.

So it is responsible for having healthy bones. Water is perhaps a very essential nutrient we should take in. The functions of water include: As a solvent which reactants of metabolic reactions are dissolved in.

It makes up most of the blood plasma which red blood cells, nutrients, hormones and other materials are carried in. It helps in lowering the body temperature in hot conditions by secreting it as sweat on the skin, the sweat evaporates using heat energy from the body, thus lowering the temperature. A perfect diet contains all of the nutrients in reasonable proportions, not too much and not too little.

The perfect diet should also contain energy as much as the total energy used by the individual. Malnutrition is eating inadequate proportions of food. In other words, an unbalanced diet means it is rich in a nutrient and low in another, or even lacking of a substance.

There are lots of effects of malnutrition, such as starvation, obesity or deficiency diseases. This is a tube that transports the food from the mouth deep into the body to the stomach.

Muscles contract and relax creating a wavy motion to push the food down. Villi and microvilli are adapted to absorption by: They give a very large surface area for faster diffusion of food molecules Each villus contains a large network of blood capillaries transporting more blood, thus faster diffusion Each villis is one cell thick, reducing the diffusion distance and making it faster Each villi contains a lacteal which absorbs fats.

Teeth are small, calcified, whitish structures found in the jaws or mouths of many vertebrates that are used to break down food.

Types of mammalian teeth: They are 4 in front of each jaw. They act like a blade to cut food eg. To cut a bite of a sandwich they have a chisel-like surface. They are two in each jaw.

They are very pointed, in humans they are used for the same purpose as incisors. However in carnivores they are longer and sharper and used to kill the prey. They have the same use as Premolars.

The tooth is divided into two parts, the crown and the root. Parts of the tooth: Made of calcium salts, it is very strong. It is covered by the enamel and surrounds the pulp cavity. It contains the nerves and blood vessels. The part of the tooth above the gum is called the crown, the part buried in the jawbone is called the root. The enamel covers the crown, the root is covered by cement.

And the tooth is held in place by fibres. Bacteria that lives in our mouth feed on these food particles, they respire anaerobically producing lactic acid. Like any acid, lactic acid reacts with the enamel and dissolves it away reaching the dentine, here we feel the toothache.

Advantages Suitable amounts prevent tooth decay It is a cheaper method of teeth caring. Disadvantages Too much causes teeth molting, illness and abdominal pain It is expensive.

The human transport system is a system of tubes with a pump and valves to ensure one way blood flow. We need a transport system to deliver oxygen, nutrients and other substances to all our body cells, and take away waste products from them. The oxygenated blood high in oxygen, red in color comes to the heart from the lungs in the pulmonary vein; the heart pumps it to the aorta an artery to the rest of the body.

The deoxygenated blood returns to the heart from the body in the vena cava a vein , the heart pumps is to the lungs to get rid of the carbon dioxide. Red color, high oxygen low Carbon dioxide. Blue color, low oxygen high Carbon dioxide. Did you notice that during one circulation, the blood went through the heart twice, this is why we call it double circulation.

When the blood is flowing away from the heart, it has a very high pressure, when it is flowing towards the heart it has a lower pressure. These are one of the smallest cells in your body, they are round with a dent in the middle, we call this shape a Biconcave disc.

The function of the red blood cells is to transport oxygen from the lungs to the body cells. A red protein called Haemoglobin, when the blood reaches the lungs, oxygen diffuses from the alveoli to the red blood cells and combines with haemoglobin forming an unstable compound called oxyhaemoglobin.

When the blood reaches the body cells, the oxyhaemoglobin is easily split into oxygen and haemoglobin again, the oxygen diffuses through the blood plasma to the cells.

They kill bacteria by engulfing them, taking them in the cell then kill them by digesting them using enzymes, this process is called phagocytosis. Most white blood cells are the phagocyte type. Unlike phagocytes, lymphocytes have a large nucleus. They are produced in the lymph nodes in the lymphatic system. Lymphocytes kill bacteria by secreting antibodies and antitoxins which kill the pathogens directly or make them easier to kill.

Each pathogen could be killed by a certain type of antibody. Their function is to transport blood away from the heart to the lungs or other body organs. The blood in the arteries always has a high pressure. The heart pumps the blood quickly into the arteries, resulting in the pressure, each time the ventricle of the heart contracts, the pressure in arteries increase, when the ventricle relaxes, the pressure falls. The lumen of arteries is also very narrow, adding to the pressure.

Blood capillaries are the smallest blood vessels in our systems. Their function is to get blood from the arteries as close as possible to the tissues in order to exchange materials with the cells, and to link arteries with veins. When arteries come near and organ or a tissue, it divides into arterioles, these arterioles divide more into several blood capillaries that go through the tissue, this is when the exchange of oxygen and food nutrients with carbon dioxide and waste products such as urea take place by diffusion.

Two of them are atria and two are ventricles. One of each of these on each side. The sides of the heart are separated by a wall called septum. Each side contains an atrium at the top and a ventricle at the bottom , there is a valve between the atrium and the ventricle in each side, it is called bicuspid valve in the left side and tricuspid valve in the right side. There are several blood vessels associated with the heart, these are: The red shows oxygenated blood and the blue shows deoxygenated blood.

Notice that the walls around the left ventricle are much thicker than the ones in the right ventricle. The reason for this is that because the left ventricle pumps blood to the whole body, so blood will travel a long distance, so it needs lots of muscles to contract and pump the blood more strongly.

However, the right ventricle pumps blood the lungs which are very close to heart, the blood does not need to be pumped very strongly. In fact, the heart needs a higher amount of blood supply than any other organ because it is working all the time, and contains a lot of muscles.

The coronary arteries are those which supply the heart tissues with blood, they branch from the aorta. CHD develops when cholesterol layers build on the walls of the coronary arteries, partially blocking the path of blood, thus this tissue of the heart is not supplied with oxygen nor nutrients, so it stops working properly.

If it is not treated at this age, a blood clot may form near the partially blocked area, completely blocking the artery, when this happens, the blood cannot function anymore, a heart attack occurs, which is extremely fatal. The causes of CHD are mostly in the diet. A diet with lots of fats, increases the chance of cholesterol building up on the walls of the artery, causing CHD, Same thing with salts.

Smoking also increases the rate of fat deposition. Guard cells are a specialised type of cells that control the passage of carbon dioxide into the cell and the passage of oxygen out of the cell by opening and closing the stomata a hole in the leaf through which gases pass so guard cells are responsible for the gas exchange.

It is the process by which plants make useful glucose out of the raw materials water and carbon dioxide, using light energy from the sun.

Water is essential for photosynthesis, it is sucked up from the soil by the roots and transported up the stem to leaves where it is put into use. Carbon dioxide, just like water is essential for photosynthesis. It moves into the leaf from the air by diffusion, through the stomata tiny wholes in the leaf. Once carbon dioxide and water are present in the leaf, one condition for photosynthesis is needed, that is light.

The two cells in the diagrams are called palisade cells the rectangular one and spongy mesophyl cell the circular one , these are the cells where photosynthesis takeplace. They a structure called chloroplasts, these structures contain a green pigment named chlorophyll, this is to trap sunlight to be used in energy, a large number of chloroplasts is required for photosynthesis. Sometimes the soil is lacking of the mineral ions needed, this problem can be solved by adding fertilisers to the soil.

Fertilisers are chemical compounds rich in the mineral ions needed by the plants. They help the plants grow faster, increase in size and become greener, they simply make them healthier and increase the crop yield. But there are disadvantages of fertilisers, such as: Excess minerals and chemical can enter a nearby river polluting it and creating a layer of green algae on the surface of it, causing lack of light in the river, thus preventing the aqua plants photosynthesizing. When living organisms in the river or lake die, decomposers such as bacteria multiply and decay, respire using oxygen.

Eutrophication takes place eventually. A green house is a placed covered by transparent polythene. In green houses, the limiting factors of photosynthesis are eliminated, and the plants are provided the most suitable conditions for a healthy, rapid growth. The soil in green houses is fertilised and very rich in mineral ions, assuring healthy, large yields.

More carbon dioxide is supplied to the crops for faster photosynthesis. The polythene walls and ceiling allow heat waves and light rays only to enter and prevent harmful waves, thus providing a high light intensity and optimum temperature, sometimes a heating system is used too. A watering system is also present. The disadvantages of green houses are that it is too small to give a large yield and that it is expensive.

The human respiratory system is made up of air passages, lungs and the respiratory muscles. It is lined by a layer of mucus and hair to trap the dust and germs in the air. It is also supplied with a dense network of blood capillaries to warm the air entering the body. Works together with the epiglottis to block the nasal cavity and the trachea during swallowing food, to prevent it from entering the respiratory system.

It is lined with a layer of ciliated epithelium cells and goblet cells which secrete mucus that traps bacteria and dust from inhaled air and gets moved upwards to the larynx by the cilia. They give the lungs a much larger surface area about 70 m2 for faster diffusion of gases between them and the blood. It surrounds all the thoracic cavity.

They are 12 pairs of ribs; one pair extends from one of the first 12 vertebrae of the vertebral column. All of the ribs except for the last two pairs are connected to the sternum, the chest bone.

Each pair of ribs is connected to the pairs above it and below it by muscle fibres called inter costal muscles.

The rib cage and the lungs are separated by an elastic layer called pleural membrane, or pleura for short. It protects the lungs from damage caused by friction with the rib cage during breathing. Together with the ribs and the inter costal muscles, it plays a big role in breathing and gas exchange. Inhaling occurs, air is absorbed by lungs, it enters the nose where bacteria and dust in it are trapped by mucus and warmed by blood capillaries.

The air enters the trachea where it is cleaned again by cilia. The bronchi take the air from the trachea to each lung. Bronchi divide into several bronchioles; each one has a group of alveoli at the end of it. In the alveoli gas exchange takes place where the oxygen rich air diffuses into the blood capillaries of the pulmonary arteries and the carbon dioxide rich gas diffuses into the alveoli to be exhaled.

The pulmonary vein carries the oxygenated fresh air to the heart where it is pumped to all the body cells. The inter costal muscles and diaphragm relax squeezing the waste gases out of the lungs, this is exhalation. Excretion is the removal of toxic materials, the waste products of metabolism and substance in excess of requirements from organisms.

Metabolism is chemical reactions taking place inside cells, including respiration. The body excretes three main waste materials. These are Carbon Dioxide, Urea and Water. Excretion is a very important feature to us because without it toxic substances will build up in our bodies and kill us. It also helps in maintaining the composition of body fluids. The Excretory System of humans is made up of 4 structures: Two kidneys, two ureters, a bladder, and the urethra. The kidneys act as a filter to filter the waste products from the blood, the ureters are tubes that transport the main waste products urine from the kidneys to the bladder, where it is stored until it is excreted out of the body through the urethra.

A kidney consists of two main structures: Cortex outer layer Medulla Between the cortex and the Medulla, there is a structure called the nephrone. The nephrone is the where filtration of toxic materials from the blood takes place. We have many of them in each kidney.

If a person gets a kidney failure, which means his kidneys cannot function anymore, they have to wash their blood on regular basis with a machine that is an alternative to the damaged kidneys. This process is called dialysis. When the blood enters the dialysis machine, it is very rich in waste materials urea, excess water and minerals.

The tubes inside the dialysis machine are made of a partially permeable membrane to allow diffusion. The tubes are also surrounded with dialysis fluid. The skin is an organ that coats your entire body. The skin is made up of two layers, the Epidermis and the dermis.

The surface of the epidermis is made of tough, dead cells. The dermis contains many useful structures. Hairs, sweat and sebaceous glands, sense receptors and erector muscles are responsible for controlling the body temperature. Blood vessels transport oxygen and nutrients to the cells of the skin. When the body is overheated, the body takes several actions to drop it by trying to lose heat in several ways: It involves widening the lumen of blood vessels of the skin, this increases blood flow and rate of heat loss.

The vessels are also brought near the surface of the skin to reduce the distance heat has to travel to escape. Sweat glands near the skin begin to secret sweat on the surface of the skin through the pores. This sweat acts as a heat consumer to absorb the body heat and use it in evaporation. The activity of sweat glands is increased when the temperature of the body rises. The muscle erectors of the hairs relax making the hairs lay flat of the skin. When the hairs are erect, they trap air in the gaps between them, this acts as an insulation and prevents heat loss.

But when the hairs are flat, less air is trapped between them so there is no insulation and more heat can be lost. When the body temperatures drop, the body takes several actions to regulate its temperature by insulation to prevent heat loss and producing heat energy: They also sink deep into the skin to increase the distance heat has to travel to escape thus reducing heat loss. This acts as insulation to reduce heat loss.

The nervous system is a system of organs working together to detect and respond to stimuli. The central nervous system is made up of the brain and the spinal cord. The spinal cord is basically a big bundle of nerve cells running through a tunnel inside the backbone which protects it while the brain is protected by the skull. The central nervous system is what gives out orders to other parts of the body to perform certain jobs.

The peripheral nervous system is the other part of the nervous system. The PNS is made of receptors and nerves that carry the impulses. When you want to bend your arm the brain send two electrical impulses, one to the bi making it contract and one to the tri telling it to relax. When the bi contracts, it becomes shorter pulling the bones to which it is attached close and bending the arm.

This causes the fibres of the tri to stretch while they are relaxed. To straighten your arm, the brain send electrical impulses to both muscles making the bi relax in order to leave the muscle it is attached to free.

The tri contracts and becomes shorter pulling the muscle it is attached to into place and straightening the arm. You have previously learned that messages are delivered around body as electrical impulses by the nervous system. Hormones are chemical substances produced by a gland, carried by the blood, which alters the activity of one or more specific target organs and is then destroyed by the liver.

What is Small Intestine?