Overview of Organ Functions and Systems

Salivary glands

Glands that produce saliva. They moisten food for easier swallowing, and initiate carbohydrate digestion with amylase.

Pancreas

Digestion and blood sugar regulation. It secretes enzymes that break down food and hormones that control blood glucose levels.

Liver

Act as a metabolic hub, processing nutrients and detoxifying the body. It filters blood, removes toxins, and produces essential substances like bile for digestion and various proteins for blood clotting. Additionally, the liver stores energy, regulates blood sugar, and plays a role in immune function.

Gastric glands

Secrete gastric juice, which is crucial for protein digestion and nutrient absorption. In the stomach lining, also secrete mucus to prevent the stomach from digesting itself.

Gallbladder

Stores and concentrates bile, a digestive fluid produced by the liver. This concentrated bile is then released into the small intestine (duodenum) to help break down and absorb fats.

Mesentery

Primary function is to attach and support the intestines to the abdominal wall, preventing them from collapsing or twisting. Allows blood and lymph vessels to supply the intestines.

Villi

Absorbing nutrients from digested food and delivering them to the bloodstream for distribution throughout the body. Increase the surface area of the small intestine.

Oral cavity

To initiate the digestive process. It also plays a vital role in breathing, speech, and sensory perception.

Stomach (Cardiac and Pyloric Sphincters)

Temporary storage, partial chemical and mechanical digestion of food, preparation of food for absorption by the intestines.

Cardiac sphincter

Ring-like muscle at the junction between the esophagus and stomach. Prevents the backflow of acidic stomach contents into the esophagus.

Pyloric sphincter

Ring muscle that controls the passage of chyme (partially digested food mixed with gastric juices) from the stomach into the duodenum.

Tongue

Taste perception, speech, swallowing, and manipulation of food within the mouth.

Pharynx

A passageway for both air and food.

Esophagus

Transport food and liquid from the mouth to the stomach. Site of peristalsis.

Chyme

Mixture of partially digested food and gastric juices, plays a crucial role in the digestive process by facilitating nutrient absorption and stimulating further digestion. Increases the surface area of food by breaking it down into smaller components.

Small intestine

Begins completion of the digestion of food, and absorbs nutrients and water from the food into the bloodstream.

Duodenum

Receives partially digested food from the stomach and mixes it with digestive juices from the accessory organs (liver, gallbladder and pancreas).

Jejunum

Second section of the small intestine. Primary site for MOST nutrient absorption in the small intestine. Contains folds and villi that increase surface area.

Ileum

Absorbs nutrients from digested food, particularly vitamin B12 and bile salts.

Large intestine

Absorbs water and electrolytes from remaining waste, form feces, and propel waste toward the rectum.

Order of the large intestine sections

Cecum → colon (ascending, transverse, descending, sigmoid) → rectum → anal canal — all play distinct roles in waste processing and elimination.

Ascending Colon

Located on the right side of the abdomen, it absorbs water and electrolytes from waste material and moves the waste upward and sideways to the transverse colon. Solidifies waste into stool.

Transverse Colon

Longest part of the colon, crosses the abdomen horizontally. Carries waste to the descending colon, and helps synthesize and absorb certain vitamins with the help of bacteria.

Descending Colon

Situated on the left side of the abdomen, primarily stores feces to be emptied downward into the rectum.

Sigmoid Colon

The final section of the colon, it contracts to increase pressure, propelling stool that it has made firm into the rectum.

Soft Palate

Facilitates swallowing, breathing, and speech by regulating airflow and preventing the backflow of food or liquids into the nasal cavity. Elevates the nasopharynx, effectively closing the communication from the oropharynx to the nasopharynx.

Hard Palate

The bony part at the roof of the mouth, essential for speech, feeding, and swallowing, providing a surface for tongue movements and separating the oral and nasal cavities.

Urinary Bladder

Temporarily stores urine produced by the kidneys until it's expelled through the urethra during urination.

Kidneys

Filters blood, removes waste products and excess water, and regulates fluid and electrolyte balance.

Ureters

Transport urine from the kidneys to the bladder.

Urethra

Transport urine from the urinary bladder to the outside of the body during urination.

Diaphragm

Dome-shaped muscle that plays a crucial role in breathing. Increases abdominal pressure to help expel different substances, contributes to preventing acid reflux by putting pressure on the esophagus, facilitate breathing as the main muscle of inspiration.

Heart

Acts as a pump, propelling blood throughout the body.

Tricuspid Valve

Located between the right atrium and right ventricle.

Bicuspid (Mitral) Valve

Located between the left atrium and left ventricle.

Pulmonary SL Valve

Controls blood flow from the right ventricle to the lungs.

Aortic SL Valve

Located between the left ventricle and the aorta.

Superior Vena Cava

Collects deoxygenated blood from the upper body and returns it to the heart's right atrium.

Inferior Vena Cava

Transports deoxygenated blood from the lower body back to the right atrium.

Aorta

Responsible for carrying oxygenated blood from the heart to the rest of the body and aids in maintaining blood pressure.

Pulmonary Artery

Carries deoxygenated blood from the heart to the lungs.

Pericardium

Sac-like membrane that surrounds and protects the heart and helps anchor the heart in the chest cavity.

Lungs

Involved in gas exchange, specifically the intake of oxygen and the expulsion of carbon dioxide.

Testes

Responsible for sperm production (spermatogenesis) and the production of the male sex hormone, testosterone.

Ovaries

Responsible for producing eggs (oocytes) and hormones, particularly estrogen and progesterone.