Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Structure and Function of Platelets01:18

Structure and Function of Platelets

The cell fragments known as platelets are disc-shaped, with an average diameter of about 3 μm and a thickness of roughly 1 μm. They play a crucial role in the body's vascular clotting system, which also involves plasma proteins, blood cells, and blood vessel tissues.
Platelets are continually replenished, circulating in the bloodstream for 9-12 days before being removed by phagocytes, primarily in the spleen. A microliter of circulating blood contains between 150,000 and 450,000 platelets, with...
Formation of the Platelet Plug01:22

Formation of the Platelet Plug

The platelet phase, the second stage of hemostasis, commences around 15-20 seconds after an injury. It follows and overlaps with the vascular phase, during which blood vessels constrict to minimize blood loss.
As the injured blood vessel contracts, endothelial cells undergo contraction, revealing collagen fibers in the basement membrane and underlying connective tissue. Furthermore, the plasma membrane of endothelial cells becomes adhesive, preparing the site for platelet adhesion. Platelets...
Classification of Leukocytes01:30

Classification of Leukocytes

Leukocytes are classified into two groups based on the presence or absence of cytoplasmic granules. Granular leukocytes, which contain granules, belong to the myeloid lineage and are divided into three subtypes: neutrophils, eosinophils, and basophils. These cells are roughly spherical and characterized by the granules in their cytoplasm.
Neutrophils are the most abundant type of granular leukocytes, comprising 50-70% of all leukocytes. They feature small, evenly distributed granules and a...
Anticoagulant Drugs: Low-Molecular-Weight Heparins01:30

Anticoagulant Drugs: Low-Molecular-Weight Heparins

Hemostasis is a crucial process that prevents excessive blood loss from damaged blood vessels. It involves various mechanisms such as vasoconstriction, platelet adhesion and activation, and fibrin formation. The importance of each mechanism depends on the type of vessel injury. In contrast, thrombosis is the abnormal formation of a blood clot within the blood vessels, leading to potential complications if the clot obstructs blood flow. Thrombosis can be caused by increased coagulability of the...
Introduction to Hemostasis01:05

Introduction to Hemostasis

Hemostasis is a complex physiological process that prevents excessive bleeding when a blood vessel is injured. It's crucial for maintaining the integrity of the circulatory system, as it ensures that our blood remains fluid while still within the vascular network and yet clots to prevent blood loss upon vessel injury.
The three phases of hemostasis involve many clotting factors present in plasma and several substances released by platelets and injured tissue cells. It is a fast, localized, and...
Clot Retraction and Fibrinolysis01:16

Clot Retraction and Fibrinolysis

After a fibrin clot is formed, the next step is clot retraction, a vital process facilitated by platelet contractile proteins, such as actin and myosin. These proteins pull the fibrin strands closer together and condense the clot. This action reduces the size of the clot, creating a smaller, denser structure that effectively seals off the damaged vessel. Clot retraction consolidates the clot and helps with wound healing by bringing the edges of the damaged blood vessel closer together.

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Plasma proteomics improves thrombosis prediction in patients with cancer and identifies targetable IL-17-driven endothelial activation.

Science translational medicine·2026
Same author

RNAs anchoring replication complex control initiation and firing of DNA replication.

Nature communications·2026
Same author

Platelet Drp1 phosphorylation provides a platform for immune-based platelet function testing.

Blood·2026
Same author

Oxidized PDI promotes thrombus formation in oxidative stress.

Blood·2026
Same author

In vivo targeting of open prothrombin with the monoclonal antibody POmAb results in anticoagulation without excessive bleeding.

Journal of thrombosis and haemostasis : JTH·2026
Same author

Molecular determinants of allosteric modulation of protein disulfide isomerase by small-molecule b'-ligands.

Redox biology·2026

Related Experiment Video

Updated: Jun 23, 2026

Live-cell Imaging of Platelet Degranulation and Secretion Under Flow
11:42

Live-cell Imaging of Platelet Degranulation and Secretion Under Flow

Published on: July 10, 2017

Platelet alpha-granules: basic biology and clinical correlates.

Price Blair1, Robert Flaumenhaft

  • 1Department of Medicine, Division of Hemostasis and Thrombosis, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.

Blood Reviews
|May 20, 2009
PubMed
Summary

Alpha-granules are vital for platelet function, contributing to hemostasis and inflammation. Research is uncovering their complex formation, secretion mechanisms, and diverse roles in various diseases.

More Related Videos

Comprehensive Analysis of Procoagulant Platelets Exhibiting Features of Necrosis, Apoptosis and Platelet Activation
04:37

Comprehensive Analysis of Procoagulant Platelets Exhibiting Features of Necrosis, Apoptosis and Platelet Activation

Published on: May 23, 2025

Procoagulant Platelet Characterization by Measuring Phosphatidylserine Exposure and Microvesicle Release from Human Purified Platelets
05:49

Procoagulant Platelet Characterization by Measuring Phosphatidylserine Exposure and Microvesicle Release from Human Purified Platelets

Published on: November 29, 2024

Related Experiment Videos

Last Updated: Jun 23, 2026

Live-cell Imaging of Platelet Degranulation and Secretion Under Flow
11:42

Live-cell Imaging of Platelet Degranulation and Secretion Under Flow

Published on: July 10, 2017

Comprehensive Analysis of Procoagulant Platelets Exhibiting Features of Necrosis, Apoptosis and Platelet Activation
04:37

Comprehensive Analysis of Procoagulant Platelets Exhibiting Features of Necrosis, Apoptosis and Platelet Activation

Published on: May 23, 2025

Procoagulant Platelet Characterization by Measuring Phosphatidylserine Exposure and Microvesicle Release from Human Purified Platelets
05:49

Procoagulant Platelet Characterization by Measuring Phosphatidylserine Exposure and Microvesicle Release from Human Purified Platelets

Published on: November 29, 2024

Area of Science:

  • Hematology
  • Cell Biology
  • Molecular Biology

Background:

  • Alpha-granules are crucial secretory organelles in platelets, originating from megakaryocytes.
  • Their cargo is sourced via regulated secretory and endocytotic pathways.
  • Defects in alpha-granule formation have identified key proteins involved in trafficking and biogenesis.

Purpose of the Study:

  • To review the formation, release, and physiological roles of alpha-granules.
  • To emphasize recent advancements in understanding alpha-granule function over the last decade.
  • To highlight the expanding roles of alpha-granules beyond hemostasis.

Main Methods:

  • Review of literature focusing on the last decade of research.
  • Analysis of proteomic studies identifying alpha-granule cargo.
  • Examination of genetic defects in alpha-granule formation in mice and humans.

Main Results:

  • Alpha-granules release hundreds of bioactive proteins upon platelet activation.
  • Mechanisms controlling alpha-granule membrane fusion and secretion are being elucidated.
  • SNAREs and SNARE accessory proteins are key regulators of alpha-granule secretion.

Conclusions:

  • Alpha-granules possess versatile functions extending to inflammation, atherosclerosis, host defense, wound healing, angiogenesis, and malignancy.
  • Understanding alpha-granule biology is critical for comprehending platelet pathophysiology in diverse diseases.
  • Continued research is essential to fully elucidate the multifaceted roles of alpha-granules.