platelet
Definition
Platelets are small, round blood cells that are essential for blood clotting. They are made in the bone marrow and have no nucleus.
Platelets are activated when they come into contact with damaged tissue. They release chemicals that attract other platelets and form a plug at the site of the injury. This plug helps to stop the bleeding.
Platelets also release chemicals that activate the clotting cascade. The clotting cascade is a series of reactions that leads to the formation of a blood clot.
Blood clots are important for preventing excessive bleeding. However, they can also be dangerous if they form in the wrong place, such as in a blood vessel in the heart or brain.
People with low platelet counts are at risk of bleeding problems. This can be caused by certain diseases, such as leukaemia or aplastic anaemia. It can also be caused by certain medications, such as chemotherapy drugs.
People with low platelet counts may need to have platelet transfusions to prevent bleeding.
How can the word be used?
The doctor diagnosed the patient with thrombocytopenia, a condition in which there are not enough platelets in the blood.
Different forms of the word
Noun:
- platelet (a small, disk-shaped blood cell that helps to stop bleeding).
- platelets (plural of platelet).
Adjective:
- platelet (of or relating to platelets).
Etymology
The word "platelet" comes from the Greek word "plakous", which means "flat cake".
The word "platelet" was first used in English in the 19th century. It was used to refer to the small, disk-shaped blood cells that help to stop bleeding.
The root of the word "platelet" is the Greek word "plako", which means "to make flat".
So, the word "platelet" literally means "flat cake". This is a reference to the fact that platelets are small, disk-shaped cells.
Question
What do platelets do?
AQA Science Exam Question and Answer
Question:
Explain the role of platelets in the process of blood clotting. Describe how platelets are activated and their significance in wound healing. Discuss any disorders or conditions related to platelets' functioning.
Answer:
Platelets are small, disc-shaped cell fragments present in blood that play a critical role in blood clotting, also known as haemostasis. When blood vessels are damaged, platelets are activated to prevent excessive bleeding. They adhere to the damaged area, forming a temporary plug that helps stop the bleeding.
Platelets are activated through a complex process involving chemical signals and changes in their shape. Once activated, they release substances that attract more platelets to the site, creating a stable clot. Over time, the clot contracts, pulling the wound edges closer together and aiding in wound healing.
Disorders related to platelets' functioning can lead to bleeding disorders or clotting abnormalities. Thrombocytopenia, characterised by low platelet counts, can result in excessive bleeding from minor injuries. On the other hand, thrombocythemia, an excessive increase in platelet counts, can lead to blood clot formation even in the absence of injury, increasing the risk of stroke or heart attack.