Types of Organs Systems

Introduction: 

Cells are the basic, structural, and functional units of all living organisms. They are the smallest units that carry out all life processes to keep the organisms alive. In unicellular organisms, the entire body of the organism is made up of a single cell, and that single cell is responsible for carrying out all life processes. On the other hand multicellular organisms are made up of many cells. In multicellular organisms the cells that are similar in structure and functions group together to form tissues.  Most of these cells are specialized to carry out a few functions in a group. 

In plants and animals, tissues of different kinds having the same functions come together to make up an organ. In multicellular organisms, different types of organs are present, and the organs that are involved in carrying out the same function form an organ system. For example, the mouth, esophagus, stomach, intestine, and anus are all different organs but are involved in carrying out the same function, i.e., digestion of food. 

CELL ORGANISATION 

Different types of organ systems:  

Circulatory system 

Organs: Heart, blood, and blood vessels   

Functions: Transportation of different gases and hormones throughout the body and elimination of cellular metabolic waste.   

Features:   

• Double circulation   
• The human heart consists of four chambers   
• The heart is composed of cardiac tissues.   
• The heart supplies the blood to all the parts of the body through a network of blood vessels that include arteries, veins, and capillaries.   

Excretory system 

Organs: Pair of kidneys, ureters, single urinary bladder, and urethra.   

Functions: Filtration of blood and eliminating unnecessary compounds and waste by producing and excreting urine.   

Features:    

• Nephron cells are the basic and functional units of the kidney.   

• The kidney removes waste materials from the blood by filtration and sends them out from the body in the form of urine.   
• The kidney passes the urine to the urinary bladder via tube-like structure ureters and removes the waste from the body through the urethra. 

Digestive system 

Organs: Alimentary canal- mouth, esophagus, stomach, small and large intestine, rectum, and anus.  

Accessory organs: Pancreas, liver, and salivary glands.  

Functions: Mechanical and chemical degradation of food to absorb into the body and use energy.  

Features:  

• Digestion involves groups of organs that perform functions in a coordinated manner.  
• Food is mechanically broken by mastication in the mouth and chemically inside the alimentary canal.  

• Multiple digestive juices and several enzymes are involved in breaking down food. 

Respiratory system 

How lungs with COPD function 

Organs: Nasal cavity, pharynx, larynx, trachea, lungs, and alveoli.   

Functions: Exchange of oxygen and carbon dioxide between the body and air, acid-base balance regulation.   

Features:   

• The lungs are the main respiratory organs that consist of two lobes.   
• In the lungs, grapes like tiny organs known as alveoli are present in which exchange of gases occurs.   

• The deoxygenated blood from the heart gets oxygenated in the lungs, and the carbon dioxide is removed from the body.   
• The oxygen which enters the body through respiration is used to generate energy.   

Muscular system 

Organs: Cardiac muscles, smooth muscles, and skeletal muscles   

Functions: Mechanical support, posture, and locomotion.   

Features:   

• The muscular system is composed of all muscles of the body.   
• Smooth muscle is found within the walls of blood vessels, the stomach and  intestines and is responsible for peristalsis.   
• Cardiac muscle cells form the heart muscle.   

• Skeletal muscles attach to the bones of the body, which carries out movements and locomotion.   

Nervous system 

Organs: Brain, spinal cord, and nerves.  

Functions: Initiation and regulation of vital body functions, sensations, and body movements.   

Features:   

Nerves form the communication network of the nervous system and are important for information processing. Nerves play a crucial role in emotions, memory, reasoning, stimuli, response, and control and coordinate activities of the body.  

Sensory receptors 

Sensory receptors are specialized to perceive a certain kind of stimulus. When they receive the stimulus, they convert the energy from the stimulus to electric signals and reach the brain via nerve cells, and then the brain gives immediate response.   

Stimuli include light, chemical, sound, temperature, etc.   

Types of sensory receptors 

Electromagnetic receptors	Mechanical receptors	Chemical receptors
These receptors can detect the Earth’s magnetic field. Many fishes, birds, amphibians, etc., use electromagnetic receptors to orient themselves. Migratory birds and sea turtles use magnetic fields to navigate.	They respond to any mechanical stimuli such as touch, movement, stretching, gravity, etc.	They respond to chemical stimuli. E.g., receptors for taste, i.e., gustatory receptors and smell, i.e., olfactory receptors, are examples of chemoreceptors.
	Touch, hearing, and body position	Taste, smell, and internal sense

Summary

• Cells are the basic, structural, and functional units of all living organisms. They are the smallest units that carry out all life processes to keep the organisms alive.
• In multicellular organisms, the cells that are similar in structure and functions are grouped together, and are called tissues.
• In plants and animals, tissues of different kinds having the same functions come together to make up an organ.
• In multicellular organisms, different types of organs are present, and the organs that are involved in carrying out the same function form an organ system.
• Sensory receptors are specialized to perceive a certain kind of stimulus. When they receive the stimulus, they convert the energy from the stimulus to electric signals and reach the brain via nerve cells, and then the brain gives immediate response.