Question

what is the name of the process by which white blood cells move in and out of blood vessels?
a diffusion
b positive chemotaxis
c diapedesis
d amoeboid motion
question 16
what is the target organ of thyrotropic hormone (th), or thyroid - stimulating hormone (tsh)?
a pituitary
b thyroid
c adrenal
d pineal

Explanation:

• For the first question:
• Diffusion is the movement of molecules from an area of high concentration to an area of low concentration. It is not specific to white - blood - cell movement in and out of blood vessels.
• Positive chemotaxis is the movement of cells (including white blood cells) towards a chemical stimulus. But it does not describe the process of moving in and out of blood vessels.
• Diapedesis is the process by which white blood cells (leukocytes) move in and out of blood vessels (through the endothelial cells of the vessel wall).
• Amoeboid motion is a form of locomotion of some cells (like amoebas and some white blood cells in general movement), but not specifically the movement in and out of blood vessels.
• For the second question:
• Thyrotropic hormone (TH) or thyroid - stimulating hormone (TSH) is secreted by the anterior pituitary. Its target organ is the thyroid gland. It stimulates the thyroid gland to produce and secrete thyroid hormones (triiodothyronine \(T_3\) and thyroxine \(T_4\)).
• The pituitary is the source (anterior pituitary secretes TSH), not the target.
• The adrenal gland is the target of other hormones like adrenocorticotropic hormone (ACTH).
• The pineal gland is involved in the production of melatonin and is not the target of TSH.

Answer:

• First question: C. diapedesis
• Second question: B. thyroid