Once the thirst hub situated in the lateral hypothalamus informs the body of dehydration, it will react by stimulating drinking behavior. The brain sends sensory messages to appropriate muscles to lift the glass of water for drinking purposes. Impulses arise from the cerebral motor compound of the brain. The impulses then move via the corticospinal tract1, which traverses via the midbrain, the pons and the medulla until it departs from the skull via the occipital foramen and goes into the spinal cord. From the spinal cord, the impulse journeys through explicit nerves that branch outwardly on the spinal column to particular muscle categories dependent on the movement.
Anatomically, to reach for the water glass, flexion of the shoulder is needed in moving the arm onward toward the frontal part of the body. Specifically, the deltoid muscle contracts, pulling on the deltoid tuberosity of humerus, thus, the flexion of the shoulder joint2.The Coracobrachialis and pectoralis major also contract, pulling on the coracoids process and cartilages of ribs 2-6, correspondingly, causing the flexion of the shoulder joint3. In addition, slight pronation of the hand is necessary to rotate the palm of the hand in the direction of the glass. Consequently, the pronator quadrates4 and pronator teres5 contract, pulling on the anterior surfaces of the ulna and medial epicondyle of the humerus, respectively, resulting in the pronation the elbow joint6, thus rotating the palm around the glass.
In order to grab the glass, flexion of the fingers is required. The action requires the four fingers to flex as one movement, and the thumb to flex as a separate movement Therefore, flexor digitorum superficialis and flexor digitorum profundus contract, pulling on the medial epicondyle of humerus and medial surfaces of ulna, respectively, causing the flexion of the carpometacarpal joint7. In addition, flexion at the thumb joint is executed by contraction of flexor pollicis longus muscle, which pulls on the anterior shaft of radius, to cause flexion of carpometacarpal of thumb joint8.
In conclusion, flexion of the arm is necessary to carry the glass to mouth. Therefore, the biceps brachii9 and muscle brachialis10 pull on head of the coracoids process and distal surface of humerus, causing the flexion of the elbow joint11. This completes the forearm flexion, which ends up with the frosty mug at my mouth. Conversely, we must conclude with a wrist adduction, opening with flexor carpi ulnaris12 , which moves the extensor carpi ulnaris13. This completes reaching for the frosty mug and bringing it to my mouth.
Through drinking, water goes into the mouth, and then progresses to the pharynx then to the esophagus14. Via the esophagus, water then reaches the pylorus of the stomach. It then enters the lower part of the gastrointestinal tract, which includes small intestine and large intestine. Exclusively, the water traverses the duodenum, jejunum, and ileum15 and then to the caecum16. Consequently, the water moves to the colon17 where most of water is reabsorbed through the arterial blood vessels. The water is then shifted to the kidneys via the bloodstream. The kidneys filter the blood, returning most of the water into the cells via osmosis. To be specific, the water enters the kidney through glomerulus in the Bowman’s capsule due to ultra filtration. After which it moves to proximal convoluted tubule, loop of Henle, distal convoluted tubule, then to the collecting duct. The water and solutes that are left in the kidneys constitute urine, which is then passed through the ureters, and stored in the urinary bladder until the bladder is ready to be emptied. The urine then passes through the urethra to be excreted.
Chewing movement necessitates the elevation of the mandible. Therefore masseter18, temporalis, and pterygoid19 muscles contract, pulling on zygomatic arch, temporal lines of skull, and lateral pterygoid20 plate, respectively, causing elevation, depression, and lateral gliding of tempromandbular joint21. In addition, the movement of the tongue muscle is also important in chewing of the wings. Therefore, hyoglossus and genioglossus muscles, which pull on greater horn of hyoid bone and the medial surface of mandible, respectively, cause depression of the tongue. In addition, elevation of tongue is achieved by contraction of palatoglossus muscle, which pulls on the anterior surface of soft palate. Finally, styloglossus muscle pulling on the styloid process retracts and elevates the tongue.
Upon ingesting, the chicken wing enters the buccal cavity22, where it is masticated and incompletely digested by the salivary amylase enzyme discharged by the salivary glands. The food then journeys down the pharynx, then to esophagus via peristalsis movement mechanism. Epiglottis stops the food from entering into the trachea. The food then moves into the stomach, initially to cardia and body of the stomach, and then to the pylorus. Food in the stomach is partly processed by digestive enzymes such as pepsin into chyme. Once food arrives at the pylorus, it enters the duodenum part of the small intestine via pyloric canal, then pyloric sphincter. The small intestine also receives bile from the gall bladder and other enzymes that digest the food. The food moves to the jejunum and ileum part of the small intestine by peristalsis. Microvilli, which are hair like structures on the intestines walls, allows for more efficient assimilation of the nutrients by increasing the surface area. The absorbed nutrients are then transported via the hepatic portal vein to the liver for filtering. Unabsorbed waste passes through the large intestine, via cecum, colon, and the rectum. The waste matter is stored as feces until it is ready to be excreted via anus.