Animal and Plant Nutrition: Processes and Systems
Nutrition encompasses the substances that living organisms use and convert into energy and matter through their own processes. These substances, found in living foods, are composed of single units.
Nutrients
Nutrients are direct and simple substances that reach the cells.
Animal Nutrition
Digestive Processes
This involves breaking down food substances into simpler forms that the body can use and transport to cells via the blood.
Gas Exchange
This is the process of taking in oxygen for metabolism and expelling carbon dioxide as waste.
Transport
The circulatory system facilitates the transport of nutrients and waste.
Metabolism
This is the process of obtaining energy from nutrients.
Excretion
This is the system by which waste products are eliminated.
Plant Nutrition
Plants absorb inorganic nutrients, water, and mineral salts through their roots. Transport pipes carry organic plant nutrients, even in non-green parts of the plant.
Evapotranspiration
Most of the water evaporates through the leaves.
Gas Exchange
This occurs through the stomata in the leaves.
Photosynthesis
Using sunlight, plants convert inorganic substances into organic substances.
Transport
During transport, organic substances are moved to each of the plant cells.
Metabolism and Cellular Respiration
Cells use organic compounds obtained from photosynthesis to achieve energy, converting these compounds into plant matter. Waste substances are expelled by the cell metabolism.
Nutrient Processing
The digestive process within the digestive system includes all the phenomena that occur, allowing animals to break down food, use the substances, and eliminate waste.
Ingestion
This is the intake of food.
Digestion
This is the breakdown of food into nutrients. There are two types of digestion:
- Intracellular: Occurs inside the cell, where each cell transforms the nutrients.
- Extracellular: Occurs outside the cell, in digestive tubes. Certain proteins, called enzymes, are secreted into the digestive tube to decompose the food.
Digestion can occur either inside or outside the body. In intracellular digestion, two types of transformations take place: mechanical and chemical.
Absorption
This is the passage of nutrients through the digestive system into the blood, which then carries them to the cells of the body.
Egestion
This is the elimination of all non-digested food waste from the digestive system.
Digestive Systems
Gastric Cavities
These are sac-like structures associated with cells, covered by a single opening. The opening serves as both the mouth and anus.
Digestive Pipeline
This is a long tube extending from the mouth to the anus.
Gas Exchange in Aquatic Animals
Water-breathing animals exchange gas through gills. There are two types of gills: external and internal.
Transport System
Liquids
In vertebrates, blood is the liquid used for transport.
Vessels
Vertebrates have three types of vessels:
- Arteries: Vessels that carry blood away from the heart.
- Veins: Vessels that return blood to the heart.
- Capillaries: Thin-walled tubes that connect veins and arteries. Gas exchange, nutrient exchange, and waste exchange occur between the external environment and the cells in the capillaries.
Heart
The heart propels blood throughout the body through contraction and expansion.
Excretion
Excretion is the process of removing waste substances from the body.