Stomata,
the pore like openings in a leaf.
gases pass though them.
Answer:
C) Release of von Willebrand factor (vWF) from the endothelium, not the epithelium.
Explanation:
Hemostasis is the physiological process of reparation and maintenance of a blood vessel to stop excess loss of blood in case of vascular injury. This process occurs in four stages:
- Vascular Injury i.e. a breach in the endothelial barrier. This results in the dislodge of endothelial cells, exposing the collagen fibers underneath.
- Vascular constriction or vasoconstriction is the constriction of the blood vessels to prevent excessive blood loss.
- Platelet plug formation involves the aggregation and adhesion of platelets to the endothelium.
- Coagulation
Platelet plug formation occurs by the adhesion of circulating platelets to the collagen fibers that have been exposed by dislodging of the endothelial cells. The endothelium, as well as the platelets release a ligand known as the von Willebrand factor (vWF). This molecule acts as a relay or bridge between the integrin receptors on the platelets and the exposed collagen fibers.
Platelets also release chemicals to attract more platelets to the wound site, resulting in more vWF release. This results in more and more platelets adhering to the endothelium, leading to platelet plug formation.
The correct answer is: A) GABA
GABA or γ-aminobutyric acid is a type of amino acid that's found in proteins. It is the main inhibitory neurotransmitter in the brain which means that GABA reduces neuronal excitability throughout the nervous system. GABA binds to its receptors that are located on the neuron’s plasma membrane. This binding causes the opening of ion channels that transport chloride ions into the cell or potassium ions out of the cell.
