Hematology is the study of blood and tissue that forms blood. Blood is an important part of the transport system. Blood is a tissue in the form of a liquid that consists of two major parts, namely the blood plasma and the grains of blood. Blood plasma is a liquid part of the blood. It is mostly large consisting of water, electrolytes, and blood proteins. Whereas blood corpuscles consist of these components:
- Erythrocytes, red blood cells
- Leukocytes (white blood cells)
- Platelets (blood clots or platelets)
In another sense, hematology is also known as a branch of medicine concerning blood cells, blood-forming organs, and abnormalities associated with cells and blood-forming organs. Everyone knows that bleeding will eventually stop when a wound occurs. There is an old wound that bleeds back. When the bleeding continues to progress, a clot of frozen blood will immediately form and harden, and the wound will recover soon.
Blood cells are divided into 3 categories. They are red blood cells that function to carry oxygen. The second is white blood cells function to produce antibodies. The last is blood chips play an important role in blood coagulation.
We have submitted several disorder related to the blood:
- Thalassemia. Genetical diseases that cause a decrease in the amount of hemoglobin
- Polycythemia vera. Blood cancer caused by gene mutations
- Leukemia. Cancer of the blood caused by the production of white blood cells in the spinal cord increases.
- Hemophilia. A hereditary disease that causes continued bleeding if there is a wound or a disturbance in blood clots.
- Lymphoma. Cancer of the blood that works on the body’s lymphatic system. White blood cells grow in large quantities and cannot be controlled anymore.
- Myelodysplastic syndrome. Early disorders before leukemia occur
- Primary thrombocythemia. Blood easily freezes and forms clots.
- Plasma cell myeloma. Disorders of plasma cells in the spinal cord
- Von Willebrand disease. Disorders caused by hereditary factors, where when the body is injured, the blood will be difficult to dry out
- Anemia. This is caused by the lack of the number of red blood cells
Hematology System in Fetus
Fetal blood flow starts from the umbilical vein, due to large pulmonary vessel resistance (higher than systemic vascular resistance) only 10% of the right ventricular output to the lungs. While the rest (90%) occurs right to left shunting through the bottali ductus arteriosus.
When the baby is born, there is a sudden release of the placenta. At the same time, the right atrial pressure becomes low, systemic vascular resistance rises and the lung expands. Pulmonary vascular resistance causes the closure of the closing foramen ovale after a few weeks. Then, blood flow in the bottali ductus arteriosus turns from left to right. This process is called transitional circulation. The closure of the ductus arteriosus physiologically occurs at 10-25 hours which is caused by contraction of smooth muscle. It occurs at the end of the pulmonary artery and anatomically at the age of 2-3 weeks.
In the newborn, blood vessel reactions are still less optimal. So, the state of blood loss, dehydration, and excess volume is also a very common occurrence. Fluid management in neonates must be done carefully and thoroughly. Systolic pressure is a good indicator to assess the circulation of blood volume and is used as an adequate parameter for volume replacement. Authoregulation of cerebral blood flow in newborns is maintained normally at systemic pressure between 60-130 mmHg. The average baby’s pulse rate is 120x / minute with a blood pressure of around 80 / 60mmHg.
Changes to the Circulatory System
After birth, the blood of a newborn baby must pass through the lungs to take oxygen and conduct circulation through the body to deliver oxygen to the tissues. To make good circulation, there must be two major changes in life outside the uterus.
The fetal blood circulation system is through these organs.
- Umbilical veins
- Derived from the umbilical cord to the lower side of the liver and under the blood. It is rich in oxygen and nutrients.
- This vein has a branch that connects the portal vein and supplies the liver.
- Ductus Venosus (from vein to vein). Its function is to connect the umbilical vein to the vena cava inferior. At this point, the blood is mixed with deoxygenated blood which returns from the lower part of the body. So, the blood is oxygenated properly.
- Foramen ovale. It is characterized as a temporary hole between the atria. Where the atria are the entrance to the majority of blood from the inferior vena cava crossing into the left atrium. The reason for this transfer is that blood does not need to go through the lungs to collect oxygen.
- Ductus arteriosus (from arteries to arteries). The duct is from the direction of the two pulmonary artery branches to the descending aorta. It enters the lower spot. Here is a subclavian artery and carotid artery.
- Hypogastric artery. Defined as the branching of the internal iliac artery and the umbilical artery when this branching enters the umbilical cord. This branching returns blood to the placenta. Blood needs 1.5 minutes to circulate and through the next trip.
Adaptation to extrauterine life
- a) As soon the baby is born, the baby breathes for the first time. Then, there is a decrease in pressure in the pulmonary arteries that resulting in a lot of blood flows into the lungs.
- b) Ductus arteriosus is closed one to two minutes after the child breathes
- c) With the cutting of the umbilical cord, blood in the inferior vena cava is reduced. Thus, the pressure in the right atrium or porch decreases.
- d) Conversely, the pressure in the left atrium increases, causing the closure of the foramen ovale.
- e) The remainder of the arterial duct becomes the ligamentum arteriosus.
- f) The remaining ductus venosus becomes the hepatic lesion ligament.
- g) The umbilical artery becomes the left and right lateral pesikoumbilical ligament.
The anatomical structure is typical of fetal circulation, the lung does not function during fetal life and the liver only functions partially. So, it is not necessary for the fetal heart to pump a lot of blood either through the lungs or liver. Conversely, the fetal heart must pump large amounts of blood through the placenta. Therefore, the anatomical arrangement of the fetal circulation system works very differently from the adult circulation system.
- Blood circulation system
In the fetus, blood circulation starts from the placenta through the umbilical vein and then partially to the liver and the other part. Then, it goes directly to the left ventricle of the heart, then to the left ventricle of the heart. From the left ventricle, the blood is pumped through the aorta throughout the body. While from the right ventricle is pumped partially to the lungs and partially through the ductus arteriosus to the aorta.
After the baby is born, the lungs will develop and result in decreased arteriolar pressure in the lung. This will be followed by a decrease in pressure in the right heart. This condition causes left heart pressure greater than right heart pressure. This is what makes the foramen ovale functionally close. This occurs in the first hours after birth. Because of the pressure in the lungs decreases and the pressure in the descending aorta rises. Also, due to biochemical stimuli (increased PaO2) and the isobliterated ductus arteriosus. Usually, this happened on the first day.
- Transition to Blood
In general, newborns are born with a high hemoglobin value. Hemoglobin F is the dominant hemoglobin in the fetal period. It will disappear in the first month of life for the first few days. Hemoglobin value will increase while plasma volume will decrease, as a result of normal hematocrit only in 51 – 56% of neonates. At birth, it rises from 3% to 6%, in the 7th to 9th week after the newborn will slowly fall. The Hb value for 2-month-old babies averages 12 g / dl.