Circulatory Systems: Open vs. Closed & Vertebrate Hearts

Circulatory Systems: Open and Closed

Two main types of circulatory systems exist: open and closed. Both share three common elements:

  1. A fluid (in echinoderms, it’s called hydrolymph; in most invertebrates, hemolymph; and in vertebrates, blood and lymph).
  2. A network of blood vessels to carry the fluid.
  3. A heart, a muscular organ that pumps the fluid.

Open Circulatory System

Typical of arthropods and most mollusks (except cephalopods). Blood vessels don’t form a complete network; instead, blood drains into

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Understanding Lipids: Types, Functions, and Classifications

Lipids: An Introduction

Lipids: They do not have a characteristic functional group but are substances of biological origin, soluble in organic solvents and insoluble in water. All lipids share a common carbohydrate-based structure, which explains their insolubility in water.

Biological Functions of Lipids

Biological functions: Lipids serve as the primary energy reserves for living organisms. They are integral components of cell membranes and play a role in regulating cellular and tissue activity.

Lipid

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Hygiene and Skin Lesions

Hygiene and Cleanliness

Hygiene and cleanliness are concepts aimed at preventing disease and preserving health.

Postural Hygiene

Proper posture to avoid injuries during daily activities or work.

Occupational Hygiene

Conservation measures for health in the workplace.

The Necessity of Hygiene as Basic Health

Virginia Henderson framed hygiene within the basic needs of individuals. Maslow set physiological needs, including thermoregulation, as a priority. The skin plays an important, essential role when in

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Photosynthesis: Unveiling the Z-Scheme and Light Reactions

Photosynthesis is the process by which green plants, algae, and some bacteria convert light energy from the sun into chemical energy in the form of glucose (a type of sugar) and oxygen. This process is crucial for the sustenance of life on Earth, as it is responsible for producing the oxygen we breathe and providing the primary source of food for many organisms.

Photosynthesis takes place in the chloroplasts of plant cells, specifically in structures called thylakoids, which are disk-like membranes

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Understanding the Cardiovascular, Blood, and Lymphatic Systems

The Cardiovascular System

The heart is the pump that moves blood through the cardiovascular system. It consists of two halves separated by a muscular wall.

Structure of the Heart

Each half of the heart is divided into an upper and lower cavity. The heart is enclosed in the pericardium, a double sac that provides a fluid-filled space for it to beat freely.

  • Myocardium: Muscle tissue that forms the heart.
  • Atria: The upper chambers of the heart.
  • Ventricles: The heart’s lower chambers.
  • Atrioventricular Valves:
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Nutrients, Digestion, and Your Body

Core Concepts in Nutrition and Digestion

Key Definitions

  • Feeding: The ingestion of food selected from the environment, making up our diet.
  • Food: Any substance (solid or liquid) usually ingested for living, nutritional, and psychological purposes.
  • Nutrition: An involuntary process by which our body extracts the nutrients our cells need from food and transforms them into its own structures.
  • Nutrients: Food substances that provide matter and energy for our cells to perform vital functions.
  • Basal Metabolism:
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