As we conclude our section on the human body we will discuss a crucial component to the homeostasis (state of balance) of our body: bodily proteins. When we hear the term “proteins” our mind usually wanders to skeletal muscle that we work so hard to build at the gym, or dietary protein like a red juicy steak. However, proteins exist in many different types and serve various purposes in the body. Below we will cover the main purposes that bodily proteins serve:
Structural proteins are strong, resilient, fibrous molecules. They serve as the framework for your body or like the beams of a building that allows for it to stand tall and withstand any weather. The most common structural proteins are keratin (allows for strength in your hair, nails, skin, and teeth) and collagen (the fibres that serve as the base to your bones, muscle, tendons, and skin).
Contractile proteins are what allow us to move. Without them we wouldn’t able to write, walk, or sit up – we would live as a completely immobile body. Although these proteins are essential to motor movement, they must function within the appropriate range. These proteins, known as actin and myosin, control the speed and strength of both heart and skeletal muscle contraction. And so, when overly active, contractile proteins may cause complications of the heart.
Transport proteins are essential in bringing vital substances to cells within the body. Some transport proteins serve as busses or taxis that carry substances through the blood stream. For example, hemoglobin is a protein that carries oxygen through the blood stream and brings it to the cells. In a similar way, serum albumin is the taxi that carries fat in your blood stream. Other types of transport proteins serve as doors or gates; they don’t move through the blood stream but they allow access into cells for specific substances. For example, aquaporins are proteins that grant access to water molecules. Other protein channels may grant access to ions, sugar molecules, etc.
Enzymes are proteins which speed up processes within our bodies. These proteins are often referred to as biological catalysts, and they act like a money exchange machine where you would insert large dollar bills and receive the same amount back in many small coins. In a similar way, enzymes break down complex molecules into simpler form, making them easier and more available for the body to use. Enzymes accelerate metabolism, digestion, liver function, blood clotting, and much more. When they are not functioning properly, our blood sugar level may significantly drop, bleeding may not be controlled, or food may be indigested causing bloating and gastric symptoms.
Hormonal proteins act as messengers in a complex communication system referred to as the endocrine and exocrine system. These messengers are essential in allowing constant recognition of the body’s condition and signalling the body to adjust when necessary. For example, the pancreas is an organ which releases a hormonal protein called insulin which regulates the levels of blood sugar in the body.
Immunoglobulins are proteins produced by the body’s immune system. There are different types of immunoglobulins and each type protects the body against different threats. For instance, immunoglobulin A fights bacteria and viruses found in saliva and other mucosal tissues (nasal fluid, tears). Other types of immunoglobulins will provide protection against viruses, bacteria, and microplasms in mediums like blood, air borne transport, etc.
Multiple types of bodily proteins can be found in every cell of the body. Some types are more concentrated in certain tissues (e.g. contractile proteins in skeletal muscle) than in others, and their location allows for them to fulfill their function more effectively. Many of these proteins need to be kept within a narrow functional range in order to promote homeostasis and prevent disease.