Human Digestive and Circulatory Systems: Functions and Components

Human Digestive and Circulatory Systems

Nutrition is the process by which a living being obtains the matter and energy needed to sustain life.

Components of Digestive Function:

• Taste: Involves eating food, breaking it down, and transporting it.
• Reduce: Food is broken down into simple molecules that cells can use.
• Absorb: Simple molecules are absorbed and passed into the bloodstream for circulation to all body tissues.
• Remove: Undigestible remains are eliminated.

Digestive Tract Components:

The Pharynx

A short part of the digestive tract, also part of the respiratory system, extending from the oral cavity to the top of the esophagus.

The Esophagus

The conduit between the pharynx and the stomach.

The Stomach

An enlarged, bag-shaped part of the digestive tube, approximately 25cm long with a capacity of about 2.5 liters.

The Liver

The largest gland in the human body, weighing about 1.5 kg, with two lobes, located near the stomach under the right lung, separated by the diaphragm.

The Pancreas

A gland about 15cm long and 80g in weight, located under the stomach, adjoining the duodenum.

The Small Intestine

A tube about 7m long and 2.5 cm in diameter, located between the stomach and the large intestine. It includes the duodenum, jejunum, and ileum.

The Large Intestine

The final part of the digestive tube, about 1.7m long. It includes the cecum, colon, and rectum, ending at the anus.

Components of the Circulatory System

The circulatory system is responsible for distributing nutrients and oxygen throughout the body and collecting waste products from cellular metabolism.

Key Components:

Blood

A tissue with cells suspended in a liquid medium called plasma.

Arteries

Blood vessels that carry blood away from the heart to the rest of the body. They are elastic and can change diameter due to muscle fibers in their walls.

Veins

Blood vessels that carry blood from the capillaries back to the heart. They are less elastic than arteries, and the pressure inside them is very low.

Capillaries

Tiny blood vessels located between arteries and veins. Their diameter is so small that blood flows very slowly, and red blood cells must deform to pass through.

The Heart

A hollow, muscular organ about the size of a fist, located in the thorax between the lungs. Its function is to pump blood to all parts of the body.