1. Brain
The brain is split into three main parts; the cerebrum (the forebrain), the cerebellum (the hindbrain) and the brain stem.
The Cerebrum is the largest area of the brain and controls all higher mental functions, such as thinking and memory. It’s made up of two halves, or hemispheres. The right controls the left side of the body, and the left controls the right side of the body.
The Frontal lobe controls thought, memory, problem solving and behaviour.
The Parietal lobe is responsible for language. It also deals with touch and how we recognise sensations, and helps us be aware of our body position.  
The Temporal lobe helps us understand and process what we hear. It’s also involved with how we learn, organise information and formation of emotions.
The Occipital lobe is where all visual information is processed, such as colour, shape and distance.
The Cerebellum is the back part of the brain, concerned with balance and coordination. These activities are carried out automatically and subconsciously.
The Brain stem controls the basic functions that are essential for maintaining life, including breathing, body temperature, heart rate and blood pressure. It also controls eye movements and swallowing. It’s a very sensitive and important part of the brain.

2. Brain

3. Heart
The heart is a muscular organ about the size of a closed fist that functions as the body’s circulatory pump. It takes in deoxygenated blood through the veins and delivers it to the lungs for oxygenation before pumping it into the various arteries (which provide oxygen and nutrients to body tissues by transporting blood around the body).
The Pericardium is a special membrane which surrounds the heart, it produces serous fluid to lubricate the heart and prevent friction between this organ and those around it. It also holds the heart in position and maintain a hollow space for the heart to expand into when it is full.
The heart wall is made of 3 layers:-
The epicardium is the outermost layer of the heart wall it is a thin layer of serous membrane that helps to lubricate and protect the outside of the heart. Below the epicardium is the second, thicker layer of the heart wall: the myocardium.
The myocardium is the muscular middle layer of the heart wall that contains the cardiac muscle tissue. This is the part of the heart responsible for pumping blood and varies in thickness in different parts of the heart.  
The endocardium is the simple squamous endothelium layer that lines the inside of the heart. The endocardium is very smooth and is responsible for keeping blood from sticking to the inside of the heart and forming potentially deadly blood clots.

4. The heart contains 4 chambers
The heart contains 4 chambers. The atria are smaller than the ventricles and have thinner, less muscular walls. They receive the blood, from the veins that carry blood into the heart. The ventricles are the larger, stronger pumping chambers that send blood out of the heart. The ventricles are connected to the arteries that carry blood away from the heart. The chambers on the right side of the heart are smaller and have less myocardium in their heart wall when compared to the left side of the heart. This is because the left side of the heart must pump the blood much further than the right side of the heart.
Heart
The Heart Valves prevent blood from flowing backwards or “regurgitating” back into the heart, there are two main types.
The atrioventricular (AV) valves are located in the middle of the heart between the atria and ventricles and only allow blood to flow from the atria into the ventricles. 
The semilunar valves are located between the ventricles and the arteries that carry blood away from the heart, they prevent blood from flowing back into the ventricles after it has left the heart.

5. Pancreas
The pancreas is a large gland with the primary function of hormone secretion. The pancreas is broken into several different subsections. The head of the pancreas is located nearest to the intestine. The body of the pancreas is the largest section, located in the center of the gland just below the stomach. The pancreas also has a tail, which is furthest from the intestine. There is a small duct, or drain, in the pancreas which leads to the common bile duct. This duct is used to drain the hormones which aid in the digestion of food. The Islets of Langerhands. These islets are small structures dotted throughout the pancreas, and are responsible for producing insulin, as well as a wide variety of other hormones used by the body. It is estimated that each pancreas contains over one million of these islets. The pancreas is involved in in the endocrine system. It produces the hormones insulin, glucagon, and somatostatin. Insulin is deficient in people with diabetes. They do not produce enough insulin or are resistant to its effects. It is responsible for regulating the amount of sugar which is absorbed into the cells of the body. Without enough insulin, the sugar remains in your bloodstream where it can cause significant health problems. The pancreas also produces enzymes to aid digestion of food. Some of these hormones include pancreatic lipase, pancreatic amylase, and trypsin.

6. Pancreas

7. Liver
The liver performs many essential functions related to digestion, metabolism, immunity, and the storage of nutrients within the body.
The liver is made of very soft, pinkish-brown tissues encapsulated by a connective tissue capsule. This capsule is further covered and reinforced by the peritoneum of the abdominal cavity, which protects the liver and holds it in place within the abdomen.
The liver consists of 4 distinct lobes – the left, right, caudate, and quadrate lobes.
Bile Ducts are tubes that carry bile through the liver and gallbladder forming a branched structure. Bile produced by liver cells drains into microscopic canals known as bile canaliculi. These bile ducts next join to form the larger ducts on the left and right. Those two hepatic ducts join to form the common hepatic duct that drains all bile away from the liver.
The internal structure of the liver is made of around 100,000 small hexagonal units known as Lobules. Each lobule consists of a central vein surrounded by 6 hepatic portal veins and 6 hepatic arteries. These blood vessels are connected by many tubes called sinusoids which contain 2 main cell types.
Kupffer cells capture and break down old red blood cells that pass through
Hepatocytes are epithelial cells that allow metabolism, storage, digestion, and bile production.

8. Liver

9. Kidneys
The kidneys are the waste filtering and disposal system of the body. As much as 1/3 of all blood leaving the heart passes into the kidneys to be filtered before flowing to the rest of the body’s tissues. While a person could live with only one functioning kidney, our kidneys are vital organs; the loss of both kidneys would lead to a rapid accumulation of wastes and death.
The kidneys are bean-shaped. A thin layer of fibrous connective tissue forms the renal capsule surrounding each kidney. The renal capsule provides a stiff outer shell to maintain the shape of the soft inner tissues. Inside the renal capsule is the soft, dense, renal cortex. Seven cone-shaped renal pyramids form the renal medulla inside the renal cortex. Each pyramid connects to a minor calyx, a small hollow tube that collects urine. The minor calyces merge to to form the hollow renal pelvis at the center of the kidney which exits the kidney at the renal hilus. This is where urine drains into the ureter.
The renal arteries branch directly from the abdominal aorta and enter the kidneys through the renal hilus. Inside our kidneys, the renal arteries diverge into the smaller arterioles of the kidneys, these make up the glomerulus.

10. Kidneys
Each kidney contains around 1 million individual nephrons, the kidneys’ microscopic functional units responsible for filtering blood to produce urine. The nephron is made of 2 main parts: the renal corpuscle and the renal tubule. The renal corpuscle is formed by the capillaries of the glomerulus and the glomerular capsule (also known as Bowman’s capsule). The glomerulus is a bundled network of capillaries that increases the surface area of blood in contact with the blood vessel walls. Surrounding the glomerulus is the glomerular capsule, special epithelial cells known as podocytes form the layer of the glomerular capsule surrounding the capillaries of the glomerulus. Podocytes work with the endothelium of the capillaries to form a thin filter to separate urine from blood passing through the glomerulus. The outer layer of the glomerular capsule holds the urine separated from the blood within the capsule. At the far end of the glomerular capsule, opposite the glomerulus, is the mouth of the renal tubule which concentrates urine and recovers non-waste solutes from the urine. The curvy first section of the renal tubule is known as the proximal convoluted tubule. The tubule cells that line this tubule reabsorb much of the water and nutrients initially filtered into the urine. Urine next passes through the loop of Henle, to the distal convoluted tubule. Urine flows to the renal pelvis and out of the kidney to the ureters.

11. Kidneys