Hey y'all, I'm back for another round of anatomy and physiology stuff. I have something to say before we begin...
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It was kind of random and somewhat sad but....ANYWHO! Today we are exploring the cardiovascular system (also called the circulatory system) which is the system that allows blood and nutrients to circulate and be transported throughout veins, arteries, organs, etc;. As you may have noticed the trend, all of the systems discussed thus far have had specific functions, so to jump right in: the functions of blood and circulation.
We'll start small with the liquids of the body: Blood.
Blood is a type of connective tissues that is composed of scattered cells within a non-cellular fluid. It is made up up of two basic components: 45% cells ( WBC, RBC, Platelets), and 55% plasma (water, amino acids, proteins, carbs, lipids, vitamins, hormones, electrolytes, cellular waste). The 45%, cells, are the red blood cells aka the erythrocytes, the white blood cells:leukocytes, and the plasma (thrombocytes)
Red blood cells (we are getting into the specifics now) have a biconcave shape. There are about five million per cubic millimeter and since they lack a nucleus, they will not divide. Red blood cells form in the bone marrow which is called hematopoesis. Their life span is somewhat long: 120 days. At this time they are phagocytized by the liver or spleen.Their main function is to transport oxygen through the body and pick up carbon dioxide.
Although red blood cells are formed in the marrow of bones, they couldn't without the help of erythropoietin: a hormone secreted by the kidneys which stimulates the formation of RBC's. This process requires vitamin B12 and folic acid. Iron is also a key factor in the ability of RBC formation because it helps synthesize hemoglobin: molecules that combine with oxygen in the blood to transport it. When RBC's aren't formed correctly, this leads to anemia. Symptoms of anemia include fatigue, shortness of breath, decreased energy, weakness, lightheaded, and heart palpitations.
If I may, let's continue on to white blood cells.
White blood cells have a general function which is to defend the body against disease-causing agents (microorganisms). There are two main types of white blood cells which are granulocytes ( granular cytoplasm), and agranulocytes (lacking granular cytoplasm). In these two categories there are subcategories.
Granulocytes.....Granular cytoplasm: Agranulocytes.....lacking granular cytoplasm
~Neutrophils ~Monocytes
~Eosinophils ~Lymphocytes
~Basophils
Neutrophils:
Eosinophils
Basophils (less than 1% WBC)
-blood vessels dilate
-fluid accumulation and swelling
-attraction of WBC's
-at site of infection, dead and damaged leukocytes, bacteria, and
body cells accumulate which results in pus.
Monocytes:
Lymphocytes:
On a separate note, we then have the plasma portion of our blood which helps initiate the formation of blood clots and is less than half the size of red blood cells. Furthermore, there is blood plasma which is the non blood-y liquid part of the blood. This is a whopping 92% water and is responsible for transporting nutrients, gasses, and vitamins as well as maintains fluids in the body and balances out electrolyte and pH levels.
But wait, there's more!
We have this lovely group called the plasma proteins which contain the Albumin, the Globulin, and the Fibrinogen. the albumin is short and sweet: it's made in the liver and is in charge of maintaining osmotic pressure and blood pressure. The globulin has three groups: the alpha and beta which hail from the liver and transports lipids and fat-soluble vitamins, and the gamaglobulin which is from the lymphatic tissues and produce antibodies for immunity. Lastly, we have the fibrinogen which is also from the liver and is the largest molecule of plasma proteins. This is important for assisting in blood clotting because the major element in blood clotting is the change of fibrinogen into fibrin.
You may be asking yourself what exactly all of these fluids go through.
So first we have arteries. These take blood away, are elastic-y and strong. the smallest arteries are called arterioles which connect two capillaries. Then there are veins which are thin and less molecular and carry blood to the heart. The smaller version of veins are called venules and they also connect to capillaries and contain valves. Furthermore, we have capillaries which penetrate nearly all tissues. Their walls are composed of a single layer of squamous cells which in turn allows for the exchange of materials between tissues and the blood itself. Lastly there is the pre-capillary sphincters which are circular and valve-like muscles at the arteriole-capillary junction.
- Circulates oxygen and removes carbon dioxide
- Provides cells with nutrients
- Removes the waste products of metabolism to the excretory organs for disposal
- Protects the body against disease and infection
- Clotting stops bleeding after injury
- Transports hormones to target cells and organs
- Helps regulate body temperature
We'll start small with the liquids of the body: Blood.
Blood is a type of connective tissues that is composed of scattered cells within a non-cellular fluid. It is made up up of two basic components: 45% cells ( WBC, RBC, Platelets), and 55% plasma (water, amino acids, proteins, carbs, lipids, vitamins, hormones, electrolytes, cellular waste). The 45%, cells, are the red blood cells aka the erythrocytes, the white blood cells:leukocytes, and the plasma (thrombocytes)
Red blood cells (we are getting into the specifics now) have a biconcave shape. There are about five million per cubic millimeter and since they lack a nucleus, they will not divide. Red blood cells form in the bone marrow which is called hematopoesis. Their life span is somewhat long: 120 days. At this time they are phagocytized by the liver or spleen.Their main function is to transport oxygen through the body and pick up carbon dioxide.
Although red blood cells are formed in the marrow of bones, they couldn't without the help of erythropoietin: a hormone secreted by the kidneys which stimulates the formation of RBC's. This process requires vitamin B12 and folic acid. Iron is also a key factor in the ability of RBC formation because it helps synthesize hemoglobin: molecules that combine with oxygen in the blood to transport it. When RBC's aren't formed correctly, this leads to anemia. Symptoms of anemia include fatigue, shortness of breath, decreased energy, weakness, lightheaded, and heart palpitations.
If I may, let's continue on to white blood cells.
White blood cells have a general function which is to defend the body against disease-causing agents (microorganisms). There are two main types of white blood cells which are granulocytes ( granular cytoplasm), and agranulocytes (lacking granular cytoplasm). In these two categories there are subcategories.
Granulocytes.....Granular cytoplasm: Agranulocytes.....lacking granular cytoplasm
~Neutrophils ~Monocytes
~Eosinophils ~Lymphocytes
~Basophils
Neutrophils:
- very active in phagocytosis of bacteria and are present in large amounts of us in wounds
- most common type of WBC (60%)
Eosinophils
- attack parasites
- control allergic reactions
- 2% of WBC
Basophils (less than 1% WBC)
- produces heparin (prevents blood clots)
- produces histamines (causes inflammatory reaction)
-blood vessels dilate
-fluid accumulation and swelling
-attraction of WBC's
-at site of infection, dead and damaged leukocytes, bacteria, and
body cells accumulate which results in pus.
Monocytes:
- precursors of macrophages and phagocytes
- 6% WBC
Lymphocytes:
- main constituents of the immune system which is a defense against the attack of pathogenic microorganisms such as viruses, bacteria, fungi, and protista
- yield antibodies and arrange them on their membrane
- 30% WBC
On a separate note, we then have the plasma portion of our blood which helps initiate the formation of blood clots and is less than half the size of red blood cells. Furthermore, there is blood plasma which is the non blood-y liquid part of the blood. This is a whopping 92% water and is responsible for transporting nutrients, gasses, and vitamins as well as maintains fluids in the body and balances out electrolyte and pH levels.
But wait, there's more!
We have this lovely group called the plasma proteins which contain the Albumin, the Globulin, and the Fibrinogen. the albumin is short and sweet: it's made in the liver and is in charge of maintaining osmotic pressure and blood pressure. The globulin has three groups: the alpha and beta which hail from the liver and transports lipids and fat-soluble vitamins, and the gamaglobulin which is from the lymphatic tissues and produce antibodies for immunity. Lastly, we have the fibrinogen which is also from the liver and is the largest molecule of plasma proteins. This is important for assisting in blood clotting because the major element in blood clotting is the change of fibrinogen into fibrin.
You may be asking yourself what exactly all of these fluids go through.
So first we have arteries. These take blood away, are elastic-y and strong. the smallest arteries are called arterioles which connect two capillaries. Then there are veins which are thin and less molecular and carry blood to the heart. The smaller version of veins are called venules and they also connect to capillaries and contain valves. Furthermore, we have capillaries which penetrate nearly all tissues. Their walls are composed of a single layer of squamous cells which in turn allows for the exchange of materials between tissues and the blood itself. Lastly there is the pre-capillary sphincters which are circular and valve-like muscles at the arteriole-capillary junction.
In order to control all of this rapid blood flow that happens day in and day out for years, we have this thing called vasoconstriction: the narrowing of blood vessel's passageway and vasodialation: the expansion of the passageway. Since blood flow through the veins isn't very efficient (because the veins are so small) there are three important factors that aid in blood movement: sympathetic nervous pump, skeletal muscle pump, and respiratory pump.
~Sympathetic Pump causes vasoconstriction which increases pressure resulting in blood being pushed back to the heart. The vein input causes not only vasoconstriction but also an increase in blood pressure.
~The Skeletal Muscle Pump causes muscle constriction causing blood towards the heart.
~The Respiratory Pump is when the lungs are expanded causing the space to decrease around the lungs (in the abdomen) which forces blood up to the heart.
When blood is forced to and from the heart our blood pressure increases. The systolic is when blood is forced out of the heart and the aortic valve opens. On a blood pressure machine, this is the high number. Diastolic is when the aortic valve closes and the ventricle relaxes. On a blood pressure machine, this is the lower number. Although the average blood pressure is 120/80 and the average heart rate is 72 this does not by any means imply that if your number is more or less than you are unhealthy or abnormal. A persons personal average is just that; it depends on the person and is different for everybody. There are many factors that contribute to the raise and lower of heart rate and blood pressure: cardiac output, blood volume (5 liters for ave. adult), blood viscosity, peripheral resistance, the list goes on.
NOW, onto the heart of the matter: the heart.
~Sympathetic Pump causes vasoconstriction which increases pressure resulting in blood being pushed back to the heart. The vein input causes not only vasoconstriction but also an increase in blood pressure.
~The Skeletal Muscle Pump causes muscle constriction causing blood towards the heart.
~The Respiratory Pump is when the lungs are expanded causing the space to decrease around the lungs (in the abdomen) which forces blood up to the heart.
When blood is forced to and from the heart our blood pressure increases. The systolic is when blood is forced out of the heart and the aortic valve opens. On a blood pressure machine, this is the high number. Diastolic is when the aortic valve closes and the ventricle relaxes. On a blood pressure machine, this is the lower number. Although the average blood pressure is 120/80 and the average heart rate is 72 this does not by any means imply that if your number is more or less than you are unhealthy or abnormal. A persons personal average is just that; it depends on the person and is different for everybody. There are many factors that contribute to the raise and lower of heart rate and blood pressure: cardiac output, blood volume (5 liters for ave. adult), blood viscosity, peripheral resistance, the list goes on.
NOW, onto the heart of the matter: the heart.
There are four main valves in the heart: two atrioventricular valves: the tricuspid valve and the mitral (bicuspid) valve, and then there are two semilunar valves: the aortic valve and the pulmonary valve which are in the arteries leaving the heart. Then we have a right atrium and a right ventricle which lead to the pulmonary veins. The left atrium and left ventricle are for the veins and lead to the aorta.
To go a little in depth on a few heart parts: the superior vena cava returns blood to the heart from the upper body, the aortic valve controls the flow of blood into the vena cava, the pulmonary valve returns oxygen to the blood from the lungs however, the pulmonary artery is the only artery that carries oxygenated blood to anywhere. Furthermore, the inferior vena cava returns blood from the lower body. The chordae tendinae holds the heart valve in place and the pulmonary valve returns the un-oxygenated blood back to the lungs.
CONNECTION
So my system of focus is the skeletal system. If you've been paying attention then it won't be so hard to connect the skeletal system with the cardiovascular. Remember how I was talking about red blood cells earlier, right? Well there you go. I mentioned how the red blood cells are found in the marrow of bones. Marrows main function is to create more and more red blood cells. Without them, our blood and body and brain would lack oxygen.
On another note, sometimes the body develops illness' or diseases that stem in the bone marrow such as leukemia which is when the bone marrow produces too many white blood cells, also known as leukocytes. In this case, the white blood cells basically overrun or "crowd out" the red blood cells and all other healthy cells which results in a decrease of oxygen and all other nutrients. Another disorder is called Aplastic Anemia which is a rare but serious blood condition where the bone marrow doesn't make enough "new blood cells". This can be caused by:
As mentioned earlier, when a person has treatable leukemia then the treatment is more-often then not chemotherapy. Sometimes when one blood disorder is fixed, another one can stem from it. After treated and rid of cancer, a person may develop Aplastic Anemia which can be triggered by chemo treatments.
Occasionally there are alternatives to chemo treatments and whatnot, but when there isn't, sometimes after chemo treatments, patients need bone marrow transplants because when the WBC's go crazy and the rest of the cells are drowned, the chemo kills the WBC's but also kills the other cells. This means that afterwards, the body is left without any " good" cells.
On frequent occasion, most diagnostics cannot be made until samples are extracted from a persons bone marrow.
It is quite hard to believe that this man is awake and comfortable throughout this entire procedure!!
To go a little in depth on a few heart parts: the superior vena cava returns blood to the heart from the upper body, the aortic valve controls the flow of blood into the vena cava, the pulmonary valve returns oxygen to the blood from the lungs however, the pulmonary artery is the only artery that carries oxygenated blood to anywhere. Furthermore, the inferior vena cava returns blood from the lower body. The chordae tendinae holds the heart valve in place and the pulmonary valve returns the un-oxygenated blood back to the lungs.
CONNECTION
So my system of focus is the skeletal system. If you've been paying attention then it won't be so hard to connect the skeletal system with the cardiovascular. Remember how I was talking about red blood cells earlier, right? Well there you go. I mentioned how the red blood cells are found in the marrow of bones. Marrows main function is to create more and more red blood cells. Without them, our blood and body and brain would lack oxygen.
On another note, sometimes the body develops illness' or diseases that stem in the bone marrow such as leukemia which is when the bone marrow produces too many white blood cells, also known as leukocytes. In this case, the white blood cells basically overrun or "crowd out" the red blood cells and all other healthy cells which results in a decrease of oxygen and all other nutrients. Another disorder is called Aplastic Anemia which is a rare but serious blood condition where the bone marrow doesn't make enough "new blood cells". This can be caused by:
- Being exposed to toxic substances, such as pesticides, arsenic, and benzene
- Radiation therapy and chemotherapy for cancer
- Certain medicines
- Infections such as hepatitis, Epstein-Barr virus, or HIV
- Autoimmune disorders
- Certain inherited conditions.
As mentioned earlier, when a person has treatable leukemia then the treatment is more-often then not chemotherapy. Sometimes when one blood disorder is fixed, another one can stem from it. After treated and rid of cancer, a person may develop Aplastic Anemia which can be triggered by chemo treatments.
Occasionally there are alternatives to chemo treatments and whatnot, but when there isn't, sometimes after chemo treatments, patients need bone marrow transplants because when the WBC's go crazy and the rest of the cells are drowned, the chemo kills the WBC's but also kills the other cells. This means that afterwards, the body is left without any " good" cells.
On frequent occasion, most diagnostics cannot be made until samples are extracted from a persons bone marrow.
It is quite hard to believe that this man is awake and comfortable throughout this entire procedure!!