Human Nutrition, Digestion, and Body Systems

What is Nutrition?

Nutrition is the set of processes by which the body obtains the substances it needs to live. It involves several stages:

• Collection of nutrients through digestion.
• Collection of oxygen through breathing.
• Distribution of nutrients and oxygen through the bloodstream.
• Elimination of waste through excretion and expulsion of carbon dioxide in the breath.

What is Digestion?

Digestion is the process by which foods are broken down into simple substances that can be used by the body. It has these phases:

• Digestion
• Absorption
• Waste Removal

Apparatus Involved in Nutrition

The digestive, respiratory, circulatory, and excretory systems are involved.

Parts of Dentition

Molars, canines, and incisors.

Digestive Tube

It is a muscular tube of different thicknesses ranging from the mouth to the anus and can measure up to ten meters. The salivary glands, liver, pancreas, and gallbladder are accessory organs of the digestive tract.

Aspects of a Healthy Diet

It must be comprehensive, balanced, targeted, with a proper distribution of food and appropriate food processing.

Respiration

Breathing involves taking oxygen from the air to the cells to extract energy from food and expelling carbon dioxide, which is released as a waste product.

Interior of the Lungs

Inside the lungs, there is a structure called the trachea, which leads the air to the lungs. When it divides, it forms the bronchi and then into smaller bronchioles. From there, it proceeds to the alveoli, where there are networks of blood capillaries (small vessels).

The Locomotor System

It's the body's system that allows for movement. It is formed by the bones, joints, and muscles.

Blood Composition

Blood is a means of transport that carries oxygen and necessary nutrients throughout the body. It consists of a liquid called plasma, which contains blood cells: red blood cells, white blood cells, and platelets.

Excretion

It is the process by which waste substances and water are removed from the blood. Excretion is carried out by the excretory system and sweat glands.

The Skin and its Parts

The skin has two main layers:

• Epidermis: This is the external, multilayered zone. The inner layers contain living cells. Some cells produce melanin, responsible for skin coloration. The layer in contact with the outside consists of dead cells, which shed gradually.
• Dermis: This is the inner layer. It contains sweat and sebaceous glands, the root of hairs, touch nerves, blood vessels, and fat.