Physiology is the field of biology concerned with the regular operations of living organisms and their constituent parts.
Physiology is a branch of biology that deals with the function of living organisms and their parts. It is a vast field that covers a wide range of topics, from the tiniest cellular processes to the functioning of entire ecosystems.
One of the primary goals of physiology is to understand how living organisms maintain Homeostasis or balance in their internal environment. Homeostasis is essential for survival, as it helps organisms adapt to changing conditions in their external environment.
Our bodies have mechanisms in place to regulate our internal temperature. For example, when we exercise, our muscles generate heat as a by-product of contraction. If this heat is not dissipated, it can build up and damage our cells.
Our blood vessels dilate to carry the excess heat away from our muscles and towards our skin, where it can be dissipated through sweating. At the same time, we may also pant or breathe more heavily to help rid our bodies of the excess heat.
Once the threat of overheating has passed, our blood vessels constrict, and we stop sweating and panting. This return to normal is an example of Homeostasis at work.
Another example of Homeostasis is the regulation of blood sugar levels. Our blood sugar levels will increase if we eat a high-sugar meal. In response, our pancreas will release the hormone insulin, which helps to shuttle the sugar out of our blood and into our cells, where it can be used for energy.
BRANCHES OF PHYSIOLOGY
These are the main branches of human physiology. Understanding how the human body works require knowledge of all of these areas of physiology.
- Homeostasis: harmful feedback mechanisms
- Cellular physiology: cell membrane potential
- Neurophysiology: neurons, action potentials
- Muscle physiology: skeletal muscle contraction
- Cardiovascular physiology: the heart, blood pressure, and circulation
- Respiratory physiology: lungs and breathing
- Digestive physiology: stomach and intestines
- Renal physiology: the kidney and urine production
- Endocrine physiology: hormones and the endocrine system
- Reproductive physiology: male and female reproduction
- Immunology: the immune system and immunity
Action potentials are electrical impulses that are generated by cells to send signals. The nervous system uses action potentials to send messages from the brain to the rest of the body. Muscle cells also generate action potentials to cause muscle contraction.
The nervous system controls skeletal muscle contraction. When a signal is sent from the brain to a muscle, it causes the release of a chemical called acetylcholine. Acetylcholine binds to receptors on the muscle cells and causes them to contract.
The respiratory system is responsible for taking in oxygen and eliminating carbon dioxide. The lungs are the principal organs of the respiratory system. Oxygen enters and diffuses into the blood. The heart pumps oxygen-rich blood from the lungs to the rest of the body.
The circulatory system delivers oxygen and nutrients to the body’s cells through the circulating blood.
The digestive system is responsible for breaking down food into nutrients that the body can use. The mouth, stomach, and intestines are the principal organs of the digestive system. Food enters the mouth, is chewed, and broken down by enzymes. The food then enters the stomach, further broken down, and mixed with digestive juices. The food then enters the intestines, where nutrients are absorbed into the bloodstream.
HOMEOSTATIC MAINTENANCE AND RESPONDING TO STIMULI
The body maintains Homeostasis by keeping the internal environment of the body stable. The internal environment includes the temperature, pH, and concentration of dissolved substances in the body. The body responds to stimuli by changing its internal environment to match the external environment. For example, if the temperature outside decreases, the body will react by increasing its internal temperature. If the concentration of a substance in the body decreases, the body will respond by increasing its production.
VITAL ORGAN SYSTEMS IN THE BODY AND THEIR FUNCTIONS
The critical organ systems in the body are:
- The respiratory system is responsible for taking in oxygen and eliminating carbon dioxide.
- The circulatory system is responsible for transporting nutrients and oxygen to tissues and removing carbon dioxide and other waste products.
- The digestive system is responsible for breaking down food and absorbing nutrients.
- The nervous system is responsible for coordinating the body’s response to stimuli.
- The endocrine system is responsible for producing hormones that regulate the body’s growth and metabolism.
- The immune system is responsible for protecting the body from infection and disease.
- The skeletal system is responsible for supporting and protecting the body.
- The muscular system is responsible for moving the body.
- The urinary system is responsible for filtering waste products from the blood and eliminating them from the body.
- The reproductive system is responsible for producing offspring.
HOW DO DISEASES DEVELOPMENT
Diseases develop when the body’s normal processes are disrupted. They can be caused by various things, including viruses, bacteria, fungi, and parasites. They can also be caused by environmental factors, such as exposure to toxins or radiation. Treatment and prevention of diseases depend on the specific cause of the disease. In some cases, such as with viral infections, there is no particular treatment, and the focus is on relieving symptoms. In other issues, such as bacterial infections, antibiotics may be used to kill the bacteria causing the infection. Disease prevention is often possible through vaccinations, which help the body build immunity to specific diseases. Other preventive measures include good hygiene practices, such as washing hands frequently and avoiding contact with sick people.
Diseases can be classified in various ways. One common practice is organizing them by the organ or system of the affected body. For example, respiratory system diseases include conditions such as asthma and bronchitis. Diseases of the cardiovascular system include conditions such as heart attacks and strokes. Other ways of classifying diseases include by their cause, such as infectious or non-infectious diseases; by their symptoms, such as acute or chronic diseases; and by how they are transmitted, such as sexually transmitted diseases (STDs) or foodborne illnesses.
Diseases can have a significant impact on an individual’s quality of life. They can lead to pain, suffering, disability, and in some cases, death. In addition, diseases can have a financial impact, as they can require expensive medical treatment and lead to lost productivity.
For more information on diseases and their prevention and treatment, please see the following resources:
- CDC: Diseases & Conditions
- World Health Organization:
THE ROLE OF GENETICS IN HUMAN HEALTH AND DISEASE
“The role of genetics in human health and disease is complex. Genetics can play a role in both causing and protecting against disease. For example, some genetic diseases are caused by mutations, or changes, in a single gene. Mutations in multiple genes cause other diseases. Moreover, some diseases are caused by environmental factors interacting with a person’s genes.
It is difficult to predict whether someone will get a disease based on their genes because most disorders involve multiple genes and the environment. However, there is increasing interest in using genetic information to predict a person’s risk of developing certain diseases. This information can help people make decisions about their health care, such as whether to take steps to prevent a disease or to get early treatment if they are at high risk.
There are different types of genetic tests. Some tests look for changes in a person’s chromosomes, proteins, or genes. Other tests measure the levels of specific substances in a person’s blood or other tissues. Still, other tests look for changes in gene activity that can’t be seen at the genetic level.
Some worry that genomic testing will lead to discrimination by insurers and employers. However, federal laws, such as the Genetic Information Nondiscrimination Act (GINA), protect people from being mistreated because of their genetic information.
WHAT ARE THE RISKS OF GENOMIC TESTING?
Like any medical test, genomic testing has some risks. There is a slight chance that the test results will be wrong; however, this can happen if the sample of DNA is not collected or handled correctly. It can also occur if the DNA is damaged during storage or processing. Another risk is that genomic testing could reveal information about a disease that cannot be treated or cured. Some worry that insurance companies or employers could use genomic test results to deny coverage or employment. However, federal laws, such as the Genetic Information Nondiscrimination Act (GINA), protect people from being maltreated because of their genetic information.
BENEFITS OF GENOMIC TESTING
Genomic testing can provide important information about a person’s health. It can help doctors:
- -Detect diseases early, when they may be easier to treat
- -Make more informed decisions about treatment options
- -Monitor the progression of a disease and adjust treatment accordingly
- -Identify genetic conditions that may affect a person’s future health
- -Provide information that can help guide important decisions about family planning
RISKS OF GENOMIC TESTING
Like any medical test, genomic testing has some risks. These risks include:
- -Inaccurate results. Although most genomic tests are accurate, false positives and adverse effects can occur. False positive results mean a test indicates a person’s disease or condition when they do not. False-negative results suggest a test indicates a person does not have an illness or need when they do.
- -Misinterpretation of results. Genomic test results can be complex, and they may require the expertise of a genetic counselor or other health care provider to interpret them correctly. Even then, there’s a chance that the results will be misinterpreted.
- -Psychological stress. Undergoing genomic testing and learning the results can cause psychological stress. This is especially true if the results are positive for a disease or condition that has no cure or may shorten your life expectancy.
- Although it is illegal in the United States to discriminate against someone based on their genetic information, this does not always happen in practice. Some people may worry about being denied insurance coverage or employment if they have certain genetic conditions.
- Before you undergo genomic testing, you must talk to your healthcare provider about the risks and benefits. It would be best if you also considered talking to a genetic counselor, who can help you understand the results and what they might mean for your health and that of your family.
HOW DO WE LEARN ABOUT PHYSIOLOGY, AND HOW HAS RESEARCH PROGRESSED OVER TIME
Learning about physiology has changed dramatically over time. In the past, most knowledge about physiology was gained through indirect observations and inferences. For example, early researchers might have observed that a particular plant always grew taller when exposed to more sunlight and inferred from this that plants need sunlight to grow.
Nowadays, we can learn about physiology directly through experimentation. By exposing plants to different amounts of sunlight and measuring their growth, we can now observe the effect of the sun on plant growth. This direct experimentation has allowed us to make much more precise measurements and discoveries about physiology.
Advances have also aided research in physiology in technology. The development of tools like microscopes and lasers has allowed us to study physiological processes at smaller and smaller scales. Computers have also allowed us to model and simulate physiological processes more accurately.
As our blood sugar levels return to normal, the pancreas stops releasing insulin. This feedback loop between the body and the pancreas helps to keep our blood sugar levels within a narrow range, even after we eat a sugary meal.
Homeostasis is a critical process that helps to keep our bodies functioning correctly. Without it, we would be unable to survive for very long.