Circulatory and Lymphatic Systems: Functions & Components
The International Environment and the Circulatory System
The internal human environment consists of:
- International fluid (plasma): It surrounds and bathes the cells.
- Blood and lymph: They collect and distribute substances the cells need and eliminate waste from the cells through the circulatory system.
The circulatory system consists of two systems:
- The Blood Circulatory System: It carries nutrients and oxygen throughout the body and collects metabolic waste for elimination. The circulatory fluid is
Understanding Blood Vessels, Heart Anatomy, and Cardiac Cycle
Blood Vessels: Arteries, Veins, and Capillaries
There are three types of blood vessels:
- Arteries
- Veins
- Capillaries
Arteries
Arteries are blood vessels with thick, elastic walls. They carry blood from the heart to the organs and branch off into smaller arteries.
Veins
Veins are blood vessels with thinner and less elastic walls than arteries. They have valves that prevent blood from flowing backward. They channel blood from the organs to the heart and are formed by the joining of small veins called venules.
Read MoreElectric Motor Components and Operation Explained
Electric Motor Components and Operation
The constitution of the electric motor comprises a casing, a fixed part or stator, and a rotating part or rotor:
Stator
The stator is a cylindrical ring composed of metal plates made and fitted under pressure into the motor housing. Its entire surface has available slots in which drivers are housed in the windings.
Rotor
The rotor rotates around the same axis as the stator. It consists of a cylinder formed by electrical sheets also pressed, with slots in its periphery.
Read MoreNeolithic Revolution: Agriculture, Pottery, and Sedentary Life
The Neolithic Revolution
About 12,000 years ago, the planet warmed up, causing the ice sheets to retreat towards the poles. This brought profound changes to the natural world. The megafauna adapted to the cold, such as the mammoth, largely disappeared, replaced by smaller to medium-sized animals. In colder regions previously dominated by steppes, large forests emerged. In warmer areas, forests were replaced by grasses, which came to dominate much of the landscape. Grasses are a large and diverse
Read MoreHotel Engineering and Maintenance: Key Aspects
Hotel Engineering & Maintenance (E&M)
The goal of the E&M department is to ensure that the hotel premises are properly defined and designed, according to the hotel’s type and concept, for the comfort of guests and the greatest efficiency, functionality, ecological principles, and operational sustainability. This “ensemble” must function in optimal conditions.
Working tool (the hotel): its premises, grounds, buildings, and contents, including technical concerns, equipment, furniture, and
Read MoreUrban Planning and Regional Organization: Key Concepts
Urban Planning Concepts
Conurbation: A continuous urban agglomeration created by the parallel growth of two or more cities that join without losing their independence.
Rururbanization: A transitional space between the country and the city where mixed crops and rural and urban lifestyles coexist.
Industrial Estate Services: Areas on the periphery with business and technology parks and business estates of detached buildings with fewer resources, which emerged from the 1950s to 1960s.
Urban Layout: The
Read MoreVolleyball Techniques: Serving, Blocking, Passing, and Attacking
Volleyball Techniques
Technical Background
Various techniques are used to drive the ball in different game situations. In all cases, the ball must be hit, not caught or thrown. Retention, drag, or accompaniment of the ball is a foul. The arbitral discretion in applying this rule is a common source of controversy for fans who attend games.
Serve
Each section begins with a kick of the ball from behind the baseline. The player throws the ball into the air and hits it, looking for weaknesses in the opponent’
Read MoreEuropean Imperialism and Global Conflict: 1870-1914
European Imperialism and Global Conflict (1870-1914)
Imperialism (16th-18th Centuries)
Between 1870 and the start of World War I in 1914, significant changes occurred. The economic downturn of 1873-1879 spurred protectionism, leading to a search for new markets, industries, and investment opportunities for growing European nations. Europe’s population surge to 450 million between 1815 and 1914 necessitated advancements in transportation. Powerful trading companies and chambers of commerce established
Read MoreChemical Bonds: Ionic, Covalent, and Metallic
Understanding Chemical Bonds: Types and Properties
A chemical bond arises when atoms interact, leading to compounds with lower energy than the separated atoms. To achieve a noble gas configuration, atoms can gain, lose, or share electrons. Depending on how this is achieved, bonds can be ionic, covalent, or metallic. The properties of compounds depend on the type of bond between their atoms.
Ionic Bond
An ionic bond occurs between metallic and nonmetallic elements. Metals give up their extra electrons
Read MoreEvolutionism, Creationism, and the Mind-Brain Problem
Evolutionism and Creationism: Contrasting Theories
Are evolutionism and creationism theories opposed? They operate within different frameworks. Evolution is a scientific theory, while creationism is a religious belief. The opposite of evolutionism (the doctrine that all species today come from more primitive species) is Fixism (the doctrine that asserts that species are separate and remain unchanged over time).
Conversely, the opposite of creationism (the doctrine that all reality originates from
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