Human Physiology: A Comprehensive Overview
Cardiac Cycles
A cardiac cycle includes all the events associated within one heart beat.
The normal heart beats in healthy adult is 75 beats/min and cardiac cycle last for 0.8 scc.
In the cardine cycle due to the pressure changes atria and ventricles alternately contract and relax, and blood flows from areas of higher blood pressure to areas of lower blood pressure.
• The term systole is used for the contraction and diastole used for the relaxation.
In a normal cardiac cycle, the two atria contract
Read MoreUnderstanding Microorganisms and Human Health
Impact of Heavy Rainfall and Floods on Disease Spread
During periods of heavy rainfall and floods, the risk of disease outbreaks increases significantly. The scarcity of clean drinking water leads to contamination with sewage and disease-causing pathogens, resulting in illnesses such as typhoid, cholera, and dysentery. Stagnant water also becomes a breeding ground for mosquitoes, which transmit diseases like malaria and dengue.
Food Safety and Preventing Food Poisoning
Consuming stale food can lead
Read MoreLevels of Organization in Living Organisms: From Cells to Systems
Levels of Organization in Living Organisms
Living organisms exhibit varying degrees of complexity, organized into distinct levels:
Subatomic Level
The fundamental building blocks of matter, including protons, neutrons, and electrons, which make up atoms.
Atomic Level
Composed of atoms, the smallest units of matter that retain their chemical properties.
Molecular Level
Molecules are formed by the union of two or more atoms through chemical bonds. They can be categorized as:
- Inorganic molecules: Water and
Biology Study Guide: Key Concepts & Processes
Understanding Evolution by Natural Selection
Natural selection is a core mechanism of evolution, where organisms with traits that enhance survival and reproduction in their environment are more likely to pass on those advantageous genes to offspring.
Scientific Theory vs. Everyday Usage
In science, a theory is a well-substantiated explanation supported by extensive evidence, unlike its casual use in everyday language.
Characteristics of Living Things
Living organisms share key characteristics: respiration,
Read MoreUnderstanding Natural Landscapes and Ecosystems
NATURAL LANDSCAPE
A natural landscape refers to the visible physical characteristics of a place that have not been significantly altered by human activities.
ELEMENTS OR FACTORS OF NATURAL LANDSCAPE
Biotic Factors
Biotic factors encompass the living organisms within an ecosystem, including plants, animals, fungi, and microorganisms. These organisms interact with each other and their environment, influencing the ecosystem’s dynamics.
Abiotic Factors
Abiotic factors are the non-living components of an ecosystem,
Read MoreRespiratory & Circulatory Systems: Structure, Function & Conditions
The Respiratory System
Structure and Function
The respiratory system facilitates gas exchange between our body and the atmosphere. It involves various organs, each with a specific role:
- Nostrils: These openings in the nose allow air to enter and exit the respiratory system. They are lined with a mucous membrane and cilia, which help filter and humidify the air.
- Epiglottis: This flap of cartilage prevents food from entering the trachea during swallowing.
- Larynx: Also known as the voice box, the larynx