human digestion system

human digestion system

Digestion 1

The presentation discusses the human circulatory system, where it states that digestion starts even before ingestion of food to the mouth, smelling or even sensing it, a process known as salicylic stimulation. Upon the introduction of food to the mouth, it is broken into smaller particles by chewing. Saliva also releases enzymes which act on the food. During swallowing, the epiglottis presses downwards to close the glottis and prevent food from entering the airway. It then moves to the pharynx and the oesophagus down into the stomach. Humans are not like the herbivores who have reverse movement of food. They have gastroesophageal sphincter that closes down once the food is in the stomach. The enzymes and acids in the stomach continue with the breakdown process as the stomach muscle mixes the food to form chime

Digestion 2

The video describes the chime movements in the small intestine. The food from the stomach is pushed into the duodenum where it continues with the breakdown. The food mixes with the enzymes from the pancreas and bile salt from the liver. Bile assists in fats digestion as well as blood purification by removing waste products. It is also in the duodenum that the peristalsis process occurs moving and mixing chime with the digestive secretions. The paste-like food then moves to ileum and jejunum for the absorption of nutrients such as protein, fats, and carbohydrates into the blood through the villus and microvillus. The rest moves to large intestines, where water is absorbed, and the rest pushed to the rectum as waste for secretion.

Respiration

Air from the external environment flows into the body through the nose. The inhalation and exhalation follow in the respiratory system where the oxygen is taken into the body while carbon IV oxide is exhaled. The oxygen during inhalation flows through the nares, where it is humidified and warmed. The nasal cavity has cilia that filters dust and any foreign particle from the air. The passage from the mouth and nasal cavity meet at the pharynx for both the digestive and respiratory systems. The pharynx branches to two paths, one for food and the other for air. The upper part of the air-only truck is the larynx, which contains vocal cords that vibrate to produce sounds. The air then flows through the trachea with cilia linings to remove fluids and other remaining particles from the air. The windpipe then branches into two bronchi, that later divides into bronchioles. The bronchioles end in alveoli, surrounded by capillaries for gaseous exchange. By diffusion process, oxygen passes to the bloodstream via capillaries to be transferred to other body cells for use.

Metabolism

There are two types of metabolism: the aerobic also cellular and anaerobic. The video begins with the cellular respiration where oxygen combines with glucose to release water, energy and carbon IV oxide. It changes the chemical energy in them to essential substances as it discards water, Carbon IV oxide, and other waste product through the metabolism process. The process involves three stages; tricarboxylic acid cycle, glycolysis, and respiratory-chain phosphorylation. Through the glycolysis process, glucose in the cells is oxidized to water and carbon IV oxide as it releases energy to different parts of the body. About forty percent of the energy remains in ATP, whereas the remaining is discharged as heat. Anaerobic takes place in the absence of oxygen.

Nephron

It is the kidney’s functional part that purifies the blood by reabsorbing essential nutrients and releasing waste in the form of urine. It has five sections consisting of arterioles, renal corpuscle, housing Bowman’s capsule and glomerulus, a network of capillaries. As blood flows through the glomerulus, there are pores which allow fluids to pass while keeping large molecules such as electrolytes, sugar, vitamins as well as reclaiming 75% of solids and water into blood. The filtrates then flow via proximal convoluted tubule having 75% reclamation. The next part is the loop of Henle whose surface allows for further absorption. The last part is distal convoluted tubule empties the diluted filtrate to collecting duct.

Your inner fish

The documentary outlay some of the secretive information regarding human ancestry within the human DNA and body structure. Shubin moves around the world, examining fossils and interacting with human anatomy students to bring out the clues about human evolution. He states that humans are inner monkeys and reptiles since the ancient man was in their form and later developed. Shubin compares the ancient human to fish with scales covering their bodies, making them look like ghosts. Even though he believes that human came from the fish family, he asserts that modern humankind would not believe such nuisance. He compares the bones of human hands to the forelimbs of other creatures meaning they had a common origin.