The brain

Brain is the center of the nervous system in all vertebrate, and the majority of invertebrate, animals. Some primitive animals such as jellyfish and starfish have a decentralized nervous system without a brain, while sponges lack any nervous system at all. In vertebrates, the brain is located in the head, protected by the skull and close to the primary sensory apparatus of vision, hearing, balance, taste, and smell.

Brains can be extremely complex. The human brain contains roughly 100 billion neurons, linked with up to 10,000 synaptic connections each. These neurons communicate with one another by means of long protoplasmic fibers called axons, which carry trains of signal pulses called action potentials to distant parts of the brain or body and target them to specific recipient cells.

From a philosophical point of view, it might be said that the most important function of the brain is to serve as the physical structure underlying the mind. From a biological point of view, though, the most important function is to generate behaviors that promote the welfare of an animal. Brains control behavior either by activating muscles, or by causing secretion of chemicals such as hormones. Even single-celled organisms may be capable of extracting information from the environment and acting in response to it.^[1] Sponges, which lack a central nervous system, are capable of coordinated body contractions and even locomotion. In vertebrates, the spinal cord by itself contains neural circuitry capable of generating reflex responses as well as simple motor patterns such as swimming or walking. However, sophisticated control of behavior on the basis of complex sensory input requires the information-integrating capabilities of a centralized brain.

Despite rapid scientific progress, much about how brains work remains a mystery. The operations of individual neurons and synapses are now understood in considerable detail, but the way they cooperate in ensembles of thousands or millions has been very difficult to decipher. Methods of observation such as EEG recording and functional brain imaging tell us that brain operations are highly organized, but these methods do not have the resolution to reveal the activity of individual neurons. Thus, even the most fundamental principles of neural network computation may to a large extent remain for future investigators to discover

What is Blood Pressure?

Blood is carried from the heart to all parts of your body in vessels called arteries. Blood pressure is the force of the blood pushing against the walls of the arteries. Each time the heart beats (about 60-70 times a minute at rest), it pumps out blood into the arteries. Your blood pressure is at its highest when the heart beats, pumping the blood. This is called systolic pressure. When the heart is at rest, between beats, your blood pressure falls. This is the diastolic pressure.

Blood pressure is always given as these two numbers, the systolic and diastolic pressures. Both are important. Usually they are written one above or before the other, such as 120/80 mmHg. The top number is the systolic and the bottom the diastolic. When the two measurements are written down, the systolic pressure is the first or top number, and the diastolic pressure is the second or bottom number (for example, 120/80). If your blood pressure is 120/80, you say that it is "120 over 80."

Blood pressure changes during the day. It is lowest as you sleep and rises when you get up. It also can rise when you are excited, nervous, or active.

Still, for most of your waking hours, your blood pressure stays pretty much the same when you are sitting or standing still. That level should be lower than 120/80. When the level stays high, 140/90 or higher, you have high blood pressure. With high blood pressure, the heart works harder, your arteries take a beating, and your chances of a stroke, heart attack, and kidney problems are greater.

Depression

Depression is a "whole-body" illness, involving your body, mood, and thoughts. It affects the way you eat and sleep, the way you feel about yourself, and the way you think about things. A depressive disorder is not the same as a passing blue mood. It is not a sign of personal weakness or a condition that can be willed or wished away. People with a depressive illness cannot merely "pull themselves together" and get better. Without treatment, symptoms can last for weeks, months, or years. Appropriate treatment, however, can help most people who suffer from depression.

The symptoms of depression may vary from person to person, and also depend on the severity of the depression. Depression causes changes in thinking, feeling, behavior, and physical well-being.

• Changes in Thinking - You may experience problems with concentration and decision making. Some people report difficulty with short term memory, forgetting things all the time. Negative thoughts and thinking are characteristic of depression. Pessimism, poor self-esteem, excessive guilt, and self-criticism are all common. Some people have self-destructive thoughts during a more serious depression.
• Changes in Feelings - You may feel sad for no reason at all. Some people report that they no longer enjoy activities that they once found pleasurable. You might lack motivation, and become more apathetic. You might feel "slowed down" and tired all the time. Sometimes irritability is a problem, and you may have more difficulty controlling your temper. In the extreme, depression is characterized by feelings of helplessness and hopelessness.
• Changes in Behavior - Changes in behavior during depression are reflective of the negative emotions being experienced. You might act more apathetic, because that's how you feel. Some people do not feel comfortable with other people, so social withdrawal is common. You may experience a dramatic change in appetite, either eating more or less. Because of the chronic sadness, excessive crying is common. Some people complain about everything, and act out their anger with temper outbursts. Sexual desire may disappear, resulting in lack of sexual activity. In the extreme, people may neglect their personal appearance, even neglecting basic hygiene. Needless to say, someone who is this depressed does not do very much, so work productivity and household responsibilities suffer. Some people even have trouble getting out of bed.
• Changes in Physical Well-being - We already talked about the negative emotional feelings experienced during depression, but these are coupled with negative physical emotions as well. Chronic fatigue, despite spending more time sleeping, is common. Some people can't sleep, or don't sleep soundly. These individuals lay awake for hours, or awaken many times during the night, and stare at the ceiling. Others sleep many hours, even most of the day, although they still feel tired. Many people lose their appetite, feel slowed down by depression, and complain of many aches and pains. Others are restless, and can't sit still.

What is Fitness?

A while back, I wrote about how GPP is basically just overall physical fitness. That may or may not be a helpful clarification; it leads to another question. Have you given any thought to what it means to be fit?A dictionary definition of the word fitness may be something like, “the ability to perform tasks” and is, in my opinion, perfectly adequate. So physical fitness would by extension be nothing more than the ability to perform physical tasks. An adequate definition, but not exactly an earth shattering concept. Knowing a definition is not understanding.

What is a heart attack?

A heart attack occurs when blood flow to the heart is blocked. Without blood and the oxygen it carries, part of the heart starts to die. A heart attack doesn't have to be deadly. Quick treatment can restore blood flow to the heart and save your life.

Your doctor might call a heart attack a myocardial infarction, or MI.
What is angina, and why is unstable angina a concern?
Angina (say "ANN-juh-nuh" or "ann-JY-nuh") is a type of chest pain or discomfort that occurs when there is not enough blood flow to the heart. Angina can be dangerous, so it is important to pay attention to chest pain, know what is typical for you, learn how to control it, and understand when you need to get treatment.

There are two types of angina:
Stable Angina is chest pain that has a typical pattern. It happens when your heart is working harder and needs more oxygen, such as during exercise. The pain goes away when you rest.
Unstable angina is chest pain that is unexpected and resting or taking nitroglycerin may not help. Your doctor will probably diagnose unstable angina if you are having chest pain for the first time or if your pain is getting worse, lasting longer, happening more often, or happening at rest.
Unstable angina is a warning sign that a heart attack may happen soon, so it requires treatment right away. But if you have any type of chest pain, see your doctor.

Health

HEALTH as “a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity.” In 1986 the World Health Organization in the Ottawa Charter for Health Promotion said health is “a resource for everyday life, not the objective of living. Health is a positive concept emphasizing social and personal resources, as well as physical capacities.” Classification systems such as the WHO Family of International Classifications (WHO-FIC) (composed of the International Classification of Functioning, Disability, and Health (ICF) and the International Classification of Diseases (ICD)) also define health.

Medicine

Medicine is the art and science of healing. It encompasses a range of health care practices evolved to maintain and restore health by the prevention and treatment of illness.Contemporary medicine applies health science, biomedical research, and medical technology to diagnose and treat injury and disease, typically through medication, surgery, or some other form of therapy. The word medicine is derived from the Latin ars medicina, meaning the art of healing.Though medical technology and clinical expertise are pivotal to contemporary medicine, successful face-to-face relief of actual suffering continues to require the application of ordinary human feeling and compassion, known in English as bedside manner.