Understanding Pressure

Pressure

• Pressure is force per unit area
• The SI unit for pressure is Pascal (Pa)

Long Answer Type

• Bernoulli's principle explains why people are warned to move away from the edge of a platform when a fast-moving train passes.
• Lateral pressure of liquid is the pressure exerted by a liquid at a given depth, acting sideways.
• Atmospheric pressure is the force exerted by the weight of air on a surface, not typically felt due to internal pressures balancing it.
• Thatched roofs are blown away by high winds or tornadoes due to pressure differences created by the wind flowing over the roof.

Special Questions (Puzzle)

• An alternate name for thrust is Force.
• The formula to determine area is Force/Pressure.
• Water is often stored behind a reservoir.
• Humans are surrounded by air, which exerts pressure on us.
• The combined name for gas and liquid is Fluid
• The SI unit of pressure is Pascal
• Water finds its own level
• A renowned swiss physicist named was Bernoulli.

The Human Body Introduction

• The human body is a complex structure, comprising a head, neck, trunk, forelimbs, and hind limbs.
• Cells are the simplest units of living matter that maintain life and reproduce, forming the basis of the human body.
• Tissues are organizations of similar cells, supported by varying amounts of non-living, intercellular substances.
• Organs are composed of different kinds of tissues that perform specific functions, such as the stomach.
• Systems are the most complex units, involving varying organs arranged to perform complex bodily functions.
• The study text refers to other source material in Fig 8.1.

Human Systems

• The circulatory system transports nutrients, oxygen, carbon dioxide, and hormones throughout the body, using the heart, blood, and blood vessels.
• The digestive system breaks down and absorbs food, eliminating waste through organs like the mouth, esophagus, stomach, intestines, rectum, and anus, with the liver and pancreas aiding by producing digestive juices.
• The endocrine system uses eight major glands to secrete hormones, regulating various bodily functions like metabolism, growth, and sexual function.
• The immune system defends against bacteria, viruses, and other pathogens using lymph nodes, the spleen, bone marrow, the thymus, and leukocytes.
• The lymphatic system contributes to the body's defense by making and moving lymph, containing white blood cells to fight infections, and returning excess fluid to the blood.
• The nervous system controls voluntary and involuntary actions, sending signals via the central (brain and spinal cord) and peripheral nervous systems.
• The muscular system consists of skeletal, smooth, and cardiac muscles that aid in movement, blood flow, and other bodily functions.
• The reproductive system enables human reproduction; the male system includes the penis and testes, while the female system includes the vagina, uterus, and ovaries, essential for conception.
• The skeletal system supports the body with 206 bones connected by ligaments, aiding in movement, blood cell production, and calcium storage.
• The respiratory system facilitates oxygen intake and carbon dioxide expulsion through the trachea, its branches, and the lungs.
• The urinary system eliminates water-soluble waste products from the body in the form of urine.
• The skin or integumentary system, is the body's largest organ.
• The skin also helps regulate body temperature and eliminates wastes through perspiration.

Vital Organs

• Vital organs are essential for survival and maintain bodily functions.
• The lungs are responsible for removing oxygen from the air and transferring it to the blood, as well as removing carbon dioxide.
• The brain receives and sends signals via nerves and hormones, governing thoughts, feelings, memory, and perception.
• Liver detoxifies harmful chemicals, breaks down drugs, secretes bile, and produces blood-clotting proteins.
• Kidneys remove waste and extra fluid and eliminate urea.
• The heart pumps blood throughout the body.

The Heart

• The study text presents an overview of the human heart
• The study text refers to other source material in Fig 8.2.
• Ancient people thought emotions came from the heart.
• Emotions actually come from the brain.
• The heart is a hollow muscular organ that pumps blood
• The heart pumps blood through rhythmic contraction (systole) and dilation (diastole).
• The heart pumps blood through lungs and the whole body
• The heart beats 72 times a minute in an adult and the force can be felt.
• It sits left of the middle of the chest, behind the sternum (breastbone) and in front of the vertebral column (spine).
• The heart mainly sits on the left side of the chest (99% of the time) and sits between the lungs
• The study text refers to other source material in Fig 8.3.
• Pericardium surround the heart and pericardial fluid prevents friction with heart.
• Blood gets into the heart, heart contracts, then squirts the blood. The blood squeezes with each heart.
• The heart has top and bottom chambers. Top chambers are the atria and bottom chambers are the ventricles.
• Chambers fill with blood returning from the body and the lungs. There is a left and a right atrium.
• The job of the ventricles is to squirt the blood to the body and lungs.
• The septum separates the left and right sides of the heart.
• Blood flow depends on the mitral or bicuspid and tricuspid valves (atria to ventricles valves), and aortic and pulmonary valves. (for blood leaving the heart)
• The valves prevent backflow of blood.
• Arteries and veins are also described, referring to blood vessels attached to the heart.
• Movement of blood in the heart and around body is called circulation. It takes less than a minute to pump blood to every cell of the body
• Blood delivers oxygen to the body. Oxygen keeps cells alive.
• Blood carries carbon dioxide and other waste products.
• The blood moves to the right ventricle than to the lungs.
• Doctors user a stethoscope and listens for lub-dub sounds that are the sounds of valves shutting.
• Contraction/squeezing of heart is found by finding the pulse.
• The pulse can be found on the wrist or next to the neck
• Resting heart rate is 70-80 beats per minute. The circulatory system supplies both oxygen and nutrients to the body
• It has a systemic loop and a pulmonary loop cycle
• systemic cycle brings vessels oxygen to the body
• A two part cycle involves vessels going to and from the lungs, and the other going to the body
• Blood comes from the lungs to the atrium of the heart. Blood then flows to the left ventricle
• The main artery of the body (aorta) is used to carry the blood
• Blood travels to the lungs; It also picks up the oxygen
• Aorta pushes blood with arteries so blood can flow to other cells
• Blood returns to the network of veins.
• The study text refers to other source material in Fig 8.7.
• After the blood goes from the upper body to the lower body again it enters the atrium
• Muscles of the heart contracts when the heart is beating from the vein to the arteries
• The hearts conduction system and the SA node has a electrical impulse that maintains a heartbeat.
• The atrial node then fires electrical charges the travels back to the ventricles
• The study text refers to other source material in Fig 8.8.
• The nodes in the heart controls where the electrical impulse is traveling.
• The "SA nodes" maintains the electrical impulse, there must be an artificial pacemaker set
• The arteries relax (diastole) and contract which is (systole).

Cardiovascular Disease

• Cardiovascular disease, also known as heart disease, is a common condition affecting many people, especially older adults.
• Cardiovascular disease includes high blood pressure, hardened arteries, chest pain, heart attacks, and strokes.
• Coronary arteries can cause chest pain, with discomfort in the neck, jaw, throat, upper abdomen, or back.
• The heart can be damaged because of discomfort in the upper body, nausea, and vomiting, as well as indigestion.
• Heart failure can cause shortness of breath, fatigue, and swelling in the feet, ankles, legs, and abdomen.
• The study text refers to other source material in Fig 8.9.
• Arteriosclerosis is caused by hardened, inflexible arteries that can no longer lengthen.
• Atherosclerosis occurs when a buildup of cholesterol and fat narrows the arteries, resulting in poor blood flow.
• Angina is a chest pain caused from the heart not getting enough blood and oxygen.
• Arrhythmia is an irregular or abnormal heart rate and can cause problems
• Congenital Defect of the heart occurs at birth and makes walls to be separated by the chambers and not closed
• Risk factors can increase heart disease.
• Risk factors include being old, other family members who have it.
• Heart disease is non-contagious
• Risk factors that can be controlled includes smoking, diet and exercise, and high blood pressure.
• The study text has not been included here