Today’s NCLEX-PN® question of the day focuses on the blood brain barrier. Do you know the answer? Let’s find out!
The nurse has explained the physiology of the blood brain barrier to a nursing student. Which statement indicates an understanding of the information?
A. “The blood brain barrier is made up of dendrites that block substances from crossing over to the brain.”
B. “The blood brain barrier is composed of neurons.”
C. “The blood brain barrier is maintained by astrocyte feet, which send signals to maintain tight junctions.”
D. “The blood brain barrier sends signals to block the entrance of certain substances.”
Scroll down for the correct answer!
The correct answer to today’s NCLEX-PN® Question is…
C. “The blood brain barrier is maintained by astrocyte feet, which send signals to maintain tight junctions.”
Rationale: The blood-brain barrier consists of layers of capillary endothelial cells and a basement membrane. It is maintained by the astrocyte feet, which send “signals” to maintain tight junctions in these areas.
Main Takeaway
The brain has three main parts. The first is called the cerebrum, which consists of the two cerebral hemispheres: the cerebellum located at the base of the skull and the brainstem, which is located right in front of the cerebellum. The cells that make up the brain are called neurons. Neurons are composed of a cell body containing all the cell’s organelles and nerve fibers extending out from the neuron cell body. These nerve fibers are either dendrites that receive signals from other neurons or axons that send signals to other neurons.
Neurons communicate through neurotransmitters, such as acetylcholine, dopamine, norepinephrine, and glutamate. Three meningeal layers cover the brain that help cushion it and direct venous flow. The blood-brain barrier consists of layers of the capillary endothelial cells and basement membrane. It is maintained by the astrocyte feet, which send “signals” to maintain tight junctions in these areas. This barrier ensures that substances entering the brain are tightly regulated.
Incorrect Answer Explanations
A. “The blood brain barrier is made up of dendrites that block substances from crossing over to the brain.”
Rationale: Dendrites do not make up the blood brain barrier. Dendrites are responsible for receiving signals from other neurons.
B. “The blood brain barrier is composed of neurons.”
Rationale: Neurons do not make up the blood brain barrier. Neurons are composed of a cell body containing all the cell’s organelles and nerve fibers extending out from the neuron cell body.
D. “The blood brain barrier sends signals to block the entrance of certain substances.”
Rationale: The blood brain barrier does not send signals to block the entrance of certain substances.
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