SIMPLE ANATOMY THE RESPIRATORY SYSTEM

Since I am keeping this simple I won't go into much detail of how it is an area of our brain that controls respiration but it is suffice to know that when the diaphragm contracts (it is a large muscle that separates our chest from our abdomen) it increases the volume in our chest cavity. At the same time the little intercostal muscles between our ribs contract and lift up the rib cage. Because the air pressures are different and due to various natural scientific laws this draws in more air into our lungs and due to certain receptor nerve cells they send a signal back to our brain instigating the opposite, diaphragm relaxes and we breathe out carbon dioxide. It is the Alveoli (see diagram above) where the interchange of gases takes place into and out of the blood stream for surrounding these tiny little balloon structures are tiny blood vessels known as capillaries, these are merely one cell thick to facilitate the body's waste carbon dioxide to pass into the alveoli and the oxygen in the air in the alveoli to pass into the blood stream.

This happens continuously throughout our lives automatically the average healthy adult 12 to 18 respirations per minute. It's important to remember that each system of the body is dependent on the others to function as they all interact with one another eg. The brain stem controls respiration and respiration is vital to bring oxygen to the body's cells and remove waste and its specialised nerve receptor cells within the aorta that lets the brain know when to evoke inhalation.

You can also see in the diagram the left lung is slightly smaller than the right this is to allow for the heart. As we breathe in through our nose the air is moistened and the whole of the respiratory tract is covered in little hairs 'Cilia' these trap debris and help waft up mucus from the lungs. The Uvula is a fleshy piece of tissue that stops food going into our Trachea (wind pipe) and the trachea leads to the Bronchus which divides into two Bronchi eventually getting smaller and smaller to becoming Bronchioles to which are attached the Alveoli.

Incidentally smoking paralyses these little Cilia rendering them unable to function and they are not able to move the mucous up out of the lungs, this is what leads to the classic smokers' cough.

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BASIC HUMAN ANATOMY PLACEMENT OF MAJOR ORGANS

Placement of the major organs and structures following on from the last two articles on here.

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SIMPLE ANATOMY AND PHYSIOLOGY, THE DIGESTIVE SYSTEM

Digestion as I mentioned previously begins in the mouth, food is chewed up assisted by the teeth and tongue and mixed with saliva. Saliva helps moisten the food and helps us swallow it, but the enzymes within Saliva, amylase and pytalin break down carbohydrates, which are complex sugars into disaccharides.  This chewed up food is now known as a bolus and is pushed down the oesophagus by the tongue. The oesophagus is a hollow muscular tube commonly known as the gullet. that leads to the stomach. The stomach is a muscular hollow organ that produces hydrochloric acid, to help break down food further and kill bacteria, it also produces Pepsin an enzyme to break down proteins. The stomach's muscular action churns up the food and it is now known as chyme as it passes into the first stage of the small intestine, the Duodenum, it is in the small intestine where the vast majority of digestion takes place.

The accessory digestive organs the pancreas and the liver now assist the process of digestion. The liver produces Bile, this is released and stored in the gallbladder and it is from there it is released into the duodenum its function is to emulsify fats and acts as a deodourant and gives faeces their brown colour. At the same time the pancreas produces digestive enzymes to further break down carbohydrates into simple sugars monosaccharides (amylase, lactase, sucrase) and (trypsin and chymotrypsin) break down proteins into polypeptides. Lipase breaks the fats down into fatty acids. 

As the broken down food continues along the small intestine the lining is covered in small projections known as Villi, these increase the absorbent area and the nutrients from the food are absorbed through those into the blood stream. Obviously its a lot more complex than this as I'm trying to keep this simple. 

The main function of the large intestine is to absorb water from the faeces and any remaining nutrients and the end result faeces is stored in the rectum until voided.

The Liver does have a very important role in the body besides manufacturing Bile as does the Pancreas and that will be explained in another blog.

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ANATOMY FOR BEGINNERS (AS A SURVEY REVEALS HALF OF UK POPULATION ARE IGNORANT) BEGINNING WITH THE MOUTH

I saw this in the Daily Mail (below) and I can't believe how ignorant some people can be about their bodies so I thought I had better enlighten them.

Starting with the mouth and keeping this relatively simple.

Beginning with the teeth a full grown adult has 32 teeth, though some people are born without the 4 third molars commonly known as wisdom teeth, they usually erupt around ages 14/15. We also have 20 milk teeth (our first deciduous teeth) which we begin to lose around ages 5 to 6 and are gradually replaced by our permanent teeth.

Diagram of the mouth, digestion begins within the mouth where food is chewed (masticated) and the action of salivary amylase and pytalin (enzymes that break down carbohydrates)

Tonsils are part of our immune system (lymphoid tissue) to help protect us from infection. The tongue as well has helping us to speak aids digestion by helping us move and chew food and is divided up into areas that help us detect flavours such as sweet, salty, sour and bitter.

Article from the Daily Mail below

Half of Britons are so clueless about their own bodies they are unable to point out where their HEART is

More than half of Britons are so clueless about their bodies that they cannot pinpoint the correct location of their heart, it emerged today.

Not only that, but we do not know how much blood we have, how many teeth are in our mouths or what roles our vital organs perform.

Many of the 2,000 respondents questioned by researchers were unable to say what our correct body temperature should be, while nearly 10 per cent were unsure of the number of kidneys we have.

There it is: Half of Britons are so clueless about their bodies that they cannot pinpoint the correct location of their heart, according to a study

Additionally, the study found 60 per cent could not name their own blood type.

The research was commissioned by the Museum Of London to mark the launch of its October exhibition Doctors, Dissection And Resurrection Men.

Jelena Bekvalac, Curator of Human Osteology at the museum, said: 'It seems we have a depressing lack of anatomical awareness.

'Perhaps we have a tendency to rely on medical authorities to do all they can for us without really understanding the way that we work.

'We are reassured by expertise and don’t take the time to understand the basics of how our own bodies function or are structured.

'The Museum of London’s new exhibition, Doctors, Dissection And Resurrection Men explores the extreme lengths 19th century medical pioneers went to to increase anatomical understanding.

'Surgeons faced a torturous dilemma - learn their skills on stolen corpses or practice on a living patient.

'And so began a gruesome trade. Body-snatchers stalked the city’s graveyards to supply fresh corpses for medical dissection.

OUR LACK OF KNOWLEDGE ABOUT OUR OWN BODIES

• 50% don't know where their heart is (centre-left of the chest)
• 75% don't know how many bones are in an adult body (206)
• Just under 50% don't know how many teeth we have (32)
• 40% don't know where their kidneys are
• Just under 10% don't know how many kidneys we have
• More than 50% don't know where their gall bladder is
• 60% of Britons don’t know their own blood type
• 66% did not know that the average adult has between five and six litres of blood
• 18% think a visor was a type of tooth (it's a surface that protects the eyes)
• 75% do not know that the liver is our biggest internal organ
• 40% think a single lung is of a greater size

'It is therefore sobering to consider our less than exemplary knowledge of basic biology.'

The study found just half of those polled could correctly identify the heart’s location in the left-centre of the chest.

And three-quarters were stumped when it came to guessing how many bones are in the adult human body. There are 206.

Nearly half were unsure as to how many teeth we have - 32 - while 40 per cent haven’t a clue where their kidney is located.

More than half couldn’t tell you where their gall bladder can be found and one in thirteen people didn’t know how many kidneys we have.

Worryingly, six in ten Britons didn’t know their own blood type.

A third of people could correctly state that the average adult has between five and six litres of blood.

Nearly a fifth of Brits, 18 per cent, thought a visor was a type of tooth.

Three-quarters of the respondents did not know that the liver is our biggest internal organ, with four in ten thinking a single lung was of greater size.

And nearly half the study couldn’t get anywhere near to guessing the healthy temperature of the human body, 37C.

Jelena Bekvalac said: 'Doctors, Dissection And Resurrection Men will provide a fascinating insight into a crucial period in our medical and social history.

'It may also help those who are a little confused by their own anatomy.'

Maggie Brown (Author)

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