DIGESTIVE smaller pieces for us to swallow. In

DIGESTIVE SYSTEMThe digestivesystem is made up of  Oral cavity Pharynx Oesophagus stomach Smallintestine Large intestine Liver Pancreas Gall bladder  The wholeprocess of digestion begins in our oral cavity, this is as soon as our foodenters our mouth. Whilst we are chewing our food our teeth are breaking downthe food into smaller pieces for us to swallow. In addition to this our salivaalso helps to breakdown food as it contains enzymes which help the chemicalbreakdown of food.  The Pharynxis part of our throat and is behind our mouth and nasal cavity but is above theOesophagus. The Pharynx allows the swallowed food to enter the Oesophagus. ThePharynx is also part of the respiratory system.

During the process ofswallowing the muscular walls help move the food through to our oesophagus. ThePharynx is a pathway for the movement of our food to our oesophagus.  The stomachis a muscular organ that is located on the left-hand side of the upper abdomenand also connected to our oral cavity via our Oesophagus. Our stomach holdshydrochloric acid and enzymes such as protease to chemically break down ourfood. Due to regular muscle contractions our stomach rumbles when it is empty.This is called segmentation, this is a never-ending process. The food in ourstomach is eventually turned into something called chime, it ispassed through to our Duodenum. Depending on how much has been eaten it maytake from 40 minutes to 3 hours for it to be passed through.

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On an average scale the adult stomachcan secure 1 litre of food and water. At the beginning and end of our stomachare muscular rings called sphincters. Sphincters help the stomach to hold ourfood in. The oesophageal sphincter does not need a lot of pressure for the foodto exit the stomach however this is different for the food to leave our stomachand go back into our oesophagus. This is known as vomiting and the process ofit going back into our oesophagus takes roughly 16 minutes. Each of theabove work together to help the breaking down of our food. The small intestineis broken down into three sections, these are called the Duodenum, Jejunum andthe Ileum.

The inner walls are coated in very tiny microvilli, microvilli aretiny hairs. These hairs allow a large amount of nutrients to be absorbed in thelining of the small intestine. 90% of the digestion happens in the smallintestine, this leaves the other 10% to take place in the largeintestine.  The beginningof the small intestine is the Duodenum.

Food from our stomach is combined withenzymes which come from our pancreas, this breaks down the food into moleculesthat can be absorbed. Bile is released from our gallbladder which is producedby our Liver, this helps neutralise the acid in our food when it first entersthe small intestine as it is very acidic. Our pancreas releases Amylase tocarry on the chemical breakdown of our food. The small intestine carries outthe chemical break down of food. Once the foodhas been broken down into smaller pieces it is then passed down into the secondsection which is called the Jejunum.

This is where the further absorption ofnutrients takes place. The Jejunum also adds its own digestive juices. The Ileum isthe third portion of the small intestine. The Ileum finishes the final bits ofabsorption, it absorbs the left over from theJejunum such as nutrients and soluble liquids. Similar to the inner walls ofthe small intestine the Ileum has tiny villi on its surface which helps theprocess of absorption take place.  The food ispassed through to the large intestine once it has been processed in the smallintestine. The large intestine is a 6 foot long musculartube. The muscular tube connects the small intestine with the rectum.

Just likethe small intestine the large intestine has many different parts to it such asthe ascending colon this includes the cecum and appendix, the transverse colonincluding colic flexures and transverse mesocolon, thedescending colon and the sigmoid colon which is an S shaped region of the largeintestine. The extraction of most the water from the food happens in the largeintestine. In addition to this the large intestine gives out liquid to thebody.

The remainder of minerals go through the colon and exit the body asfaces. The faeces are made to exit our body by frequent muscle contractions thecontractions are known as peristalsis, these contractions also happen in ouroesophagus to move our food into the small intestine. The large intestinecontains 700+ different types of bacteria. Some of the bacteria producevitamins which the large intestine can absorb, on the other hand other producegases. In addition to this the smaller our appendix is the more likely you areto develop appendicitis which can cause a lot of trouble such as pressure fordoctors and nurses to allow you to keep your appendix.   The liver isthe largest internal organ in our body.

It is located in the right upper sectionof the abdomen. The liver just like many other organs is protected by our ribs.The livers main job is to filter the blood from our digestive tract before itenters the rest of our body. The liver produces proteins that are important forblood clotting and other functions in our body. The bile that is released fromour gallbladder is produced by our liver however, the gall bladder helpsregulate how much is released and how often it is released into the smallintestine.  The pancreasis located in the abdomen and is the size of a hand. In addition to this thepancreas is connected to the Duodenum. The pancreas is one of the mostimportant parts of digestion as it let out lots of enzymes into the smallintestine where most work is done to help digest our food properly.

Thepancreas is also important as it releases hormones such as insulin and glucagoninto our blood stream. The hormones that are released also help regulate ourmetabolism. It also controls the blood sugars this is because the glucagon turnsglycogen back into glucose which can be mixed into the blood. 90% of ourpancreas is used for producing digestive enzymes, the enzymes are produced bycells within our pancreas called acinar cells. These enzymes help makecarbohydrates, fats and proteins smaller. The pancreas also creates its ownjuice known as pancreatic juice, this helps the pancreatic enzymes functionproperly.  Cardiovascular systemThe cardiovascular system includes  1.

     The heart Our blood Blood vessels The heart islocated behind the breast bone and slightly to the left. A common fact peopleknow about the heart is that it is the size of your clenched fist and is amuscular organ. Our heart is made up of 4 different parts these are calledchambers.  At thetop of our heart is the left and right atrium. The two atriums put together arecalled atria’s, the atriumsboth fill with blood that is coming back from our lungs. At the bottom of ourheart underneath our left and right atria’s are our left and right ventricles.

Our left and right ventriclesrelease blood that is pumped to our lungs and around our body. Just like ournose our heart is separated by a thick wall of muscle called a septum, thisseparates the right and left sides. The left side of the heart is where the bloodenters deoxygenated. Deoxygenated blood is pumped to the lungs and then returnsto the right side of our heart oxygenated and is then pumped around the body.

Oxygenated blood is pumped around the body and is used by muscles and otherorgans. The right side of our heart is the side that pumps out de-oxygenatedblood and the left side pumps out oxygenated blood.  Our bloodvessels are arteries, veins and capillaries. Arteries are made up ofnon-elastic fibres, muscle and lumen. Due to the blood leaving the heart at avery high pressure the arteries have to have a thick muscular wall in additionto this, the thick muscular wall helps force the blood along by contracting.Our arteries carry mostly oxygenated blood away from our heart to the rest ofour body.

  On the otherhand, our veins have non-elastic fibres however they are still muscular andstill have lumen in them. As a pose to arteries veins have a thinner and lessmuscular wall because the blood is at a lower pressure in the veins then it isinside the arteries. Our veins have something called valves inside them, thisis to prevent the back flow of blood.

We have 4 different valves, these areaortic valve, mitral, pulmonary valve and the tricuspid valve. The pulmonaryvalve and the aortic valve work together to control the flow of blood out ofthe ventricles. The tricuspid valve and the mitral valve also work together tocontrol the flow of blood from the atria into the ventricles. The blood in ourveins is carried from the rest of our body to our heart this means our veinscarry mostly deoxygenated blood as all the oxygenated blood has been used byour muscles and other organs.   Ourcapillaries are the smallest vessels in our body. They are the surface wherethe nutrients and oxygen are transferred into other tissues from ourbloodstream, this is known as diffusion.

Our capillaries are the reason ourarteries and veins connect. Capillaries carry both oxygenated and deoxygenatedblood.  Theblood exits our heart in vessels called arteries and comes back to our heartthrough our veins which are also vessels. Once the blood has returned to ourheart it is then sent back to our lungs to put air into our blood after thishappens the blood then travels back to our heart to be pumped back around ourbody.  MUSCULAR SKELETALSYSTEM Themuscular skeletal system is known for its protection and its support andmovement. The muscular skeletal system is made up of our body’s larger bonesand muscles in addition to this our joints such as elbows and knee caps are partof this system too as they allow movement in our body. The muscular skeletalsystem gives our body good structure, without the muscular skeletal system ourbody would be all flabby and out of shape and vital organs will not beprotected.

Our actual bones are made up of hard bone, soft bone and bonemarrow.  Theout-side layer of our bone is a thin closely compacted substance that holds ourblood and nerve vessels that supplies our bone with the right nourishment togrow and maintain health this layer is called the Periosteum. The next layer istypically known has the ‘hard’ layer, this is the layer you see on the humanskeleton. The next layer is made up of bones that are still very strong but notas hard as a compact bone, in addition to this this layer contains cancellousbones.

Cancellous bones provides alayer of protection for the inner bone. Inside the bone is bone marrow which issimilar to a thin jelly substance, its job is to produce blood cells. Almostevery bone in our body is produced of the same thigs.

  A joint is where two bones fit into anotherbone which is rounded, the rounded shape holds the bone to be held securelywhich enables movement. Muscles are attached to our bones by something called atendon, a tendon is made up of strong fibrous tissue. Similar to a tendon amuscle is a bundle of strong fibrous tissues. Muscles give our body powerfulbody strength e.g power to run.

  PROTECTION:Many different parts of the muscular skeletal system protects different bodyorgans. The brain and its soft tissues are both protected by the Cranium whichis also known as the skull. In addition to this, the heart and lungs areprotected by our 12 pairs of ribs.

   MOVEMENT:Our body is enables to move due to the fact our bones, muscles and joints workas one to allow us to walk, sprint and run. In addition to this the Vertebraeis a vital bone that allows us to bend, stretch and rotate our body. Ourmuscles produce muscular contractions that cause our bones to move whichresults in physical action. Our bottom jaw-bone is jointed to the cranium whichenables us to perform a chewing process.   SUPPORT:All 206 bones in our body work together to support our body day by day. Thevertebrae supports ourhead along with giving us a good back structure.

Our leg bones are extremelystrong as they hold up our body weight to support our upper body.      MAJOR MUSCLES IN OUR BODY:                                    1.                 Trapezius 2.

                 Triceps 3.                 Latissimus dorsi 4.                 Gluteals 5.                 Hamstrings 6.                 Gastrocnemius 7.                 Quadriceps 8.                 Abdominals 9.                 Biceps 10.

             Pectorals 11.             Deltoids    Endocrine systemThis system is made up of glandsthat produce and release hormones in our body.in addition to this the endocrinesystem produces and releases chemicals that controls and balances the activityof our organs and cells. The hormones that are produced by the endocrine systemcontrol the body’s growth and development, metabolism, sexual behaviour,reproduction and sleeping patterns.The endocrine system is made upof:Hypothalamus- The hypothalamus gland is a small gland that contains a numberof tiny nuclei this gland regulates body temperature, sex drive, hunger &thirst, mood swings, sleeping patterns. In addition to this the Hypothalamus isa section within the brain therefore this part of the brain is home to thePituitary gland and other glands within our body.

The hypothalamus gland linksour endocrine system to the nervous system, it is linked to the nervous by ourpituitary gland.Pituitary gland- The pituitary gland is found just below the Hypothalamus glandwhich is found in a section within our brain. This gland is the size of a pea.The pituitary gland and the hypothalamus gland are both attached by nervefibres. This certain gland produces vital hormones which are chemicals thatcontrol other bodily functions.

Thyroid- Along with other glands in the endocrine system the thyroidgland produces that also regulate our body’s metabolism. Along with regulatingthe body’s metabolism the thyroid glands also regulates the body’s heart rate,digestion activity, control of our muscles, brain growth & development andbone maintenance. parathyroidsAdrenal glandPineal bodyReproductiveglands PancreasThemajor organs in our endocrine system are highlighted above in yellow.

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