Final answer:
The descriptions provided discuss the characteristics of the blood-brain barrier and the blood-CSF barrier. The descriptions a and d are specific to the blood-brain barrier, b pertains to both barriers, and c is exclusive to the blood-brain barrier.
Step-by-step explanation:
When it comes to the question of whether each description pertains to the blood-brain barrier, the blood-CSF barrier, or both, the answers are as follows:
- a. Guards the blood capillaries throughout the brain: This pertains to the blood-brain barrier, which is responsible for shielding the brain from various substances in the circulatory system.
- b. Utilizes the endothelial cells of the capillaries: This is a characteristic of both the blood-brain barrier and the blood-CSF barrier.
- c. Astrocytes contribute to the cell junctions: This description is specific to the blood-brain barrier, where astrocytes provide structural and functional support to the tight junctions within the capillaries of the brain.
- d. Utilizes perivascular feet: Again, this refers to the blood-brain barrier. The astrocyte perivascular feet (end feet) envelop the capillaries and are integral to the maintenance of the barrier's integrity.