Circulatory System

General:

Circulation is the process of materials moving around the body internally. Materials like glucose or oxygen must be absorbed and expelled in order to be moved from one location in the organism to another.
Circulation depends on other life processes in order to function. For instance, it depends on gas exchange in order for hemoglobin to transport oxygen to the cell and for carbon dioxide to be transport to the lungs to be exhaled out. Circulation depends on the absorption of nutrients because once they enter the cell circulation takes over and transports the nutrients like glucose to the cells that need it. Circulation doesn’t just get molecules to the cells; it can also take them away. It relates to excretion because circulation transports the molecules to the kidneys in order to be expelled from the body. Without circulation there would be no way for the waste to exit the organism.

In unicellular organisms, circulation acts as a method of nutrient reception. Unicellular organisms do not require a circulatory system, per se, because their body layouts are so simple.
Cnidarians (sea anemone) utilize circulation in order to diffuse nutrients and wastes in and out of the system. This can be done by exchanging material across the body surface. Nutrient and waste exchange happens in the central cavity of the sea anemone, where digestion occurs.
In plants, phloem accomplishes the same objective as the circulatory system in animals. In a leaf cell, for example, sucrose and water enter into the phloem and pressure flow causes the nutrients to move around the cells of the leaf. Pressure flow occurs when phloem sap moves up the structure of the leaf exerting pressure and pushing other nutrients along with it.

Adaptations:

Circulatory systems are necessarily required for all organisms because their body plans are simple enough or have enough surface area where molecules can be transported quickly.
There are open systems where the circulatory fluid surrounds the tissue directly for exchange. There is less energy used for exchanges of materials with this type of system and it also helps with serving other functions. For example, spiders use the hydrostatic pressure that’s generated to extend their legs.
There are closed systems where the circulatory fluid never leaves the vessels and exchange is done with small vessels that allow for diffusion of materials. There’s higher blood pressure with this system which enables the transportation of oxygen and other nutrients in larger more active organisms. It also helps regulate the amount of blood in different parts of the organism’s body. For example, fish have a closed system to and pump blood to the gills to get it reoxygenated.

The ions and proteins dissolved in the plasma and the blood cells together function in osmotic regulation, transport, and defense.
The dissolved salts in the plasma help maintain the osmotic balance and ions buffer the blood

Oxygen and nutrients can diffuse in and out of the capillaries to exchange those materials with interstitial fluid. Fluid is pulled out of capillaries by blood pressure and blood proteins pulls the fluid back in.

Respiratory System - supply the body with oxygen. In mammals, this oxygen must be transported through the body, which is the job of the circulatory system. A lack of oxygen received by the respiratory system causes blood to be improperly flowing in the blood, causing the body to weaken.
Digestive System - converts sugars from food for transport through the circulatory system. If the digestive system were malfunctioning, the sugars could not power blood cells for transport.

Feedback Mechanism - homeostasis. The circulatory system allows for body temperatures to remain constant. When body temperature becomes too high, blood vessels dilate and temperature decreases. When body temperatures are too low, blood vessels in skin construct, reducing heat loss. Both of these are examples of negative feedback.
Circulatory “Diseases”

The cause of this is from a buildup of a plaque of cells and cholesterol in the blood vessels, this could lead to a heart attack.
There are no symptoms until a more serious complications, but they can be visualized by X-rays.
Treatment is medication, diet modification, and lifestyle modification.

Chest pain which is often accompanied by shortness of breath, fatigue and nausea.
Typically caused by a lack of blood to the heart muscle, and the heart pains are associated with a greater demand for it.
Nitroglycerin tablets are often taken to relieve the pain by increasing blood flow to the heart muscle.

This isn't a disease but can indicate a heart problem and murmurs can be present at birth or later in life.
An abnormal one won’t show symptoms. However shortness of breath, enlarged liver, chronic cough, and fainting could indicate a heart problem.
Innocent heart murmurs occur when blood flows through the heart more rapid than normal and abnormal heart murmurs are often due to acquired heart valve problems and occur more in people with structural heart issues.
Medication will depend on your heart problem and this includes medicine to prevent blood clots or beta blockers, but innocent murmurs don’t have treatments but the doctor may monitor it.