Chapter 12 assignment – Attempt 1 Art-labeling Activity: Figure 12.4b Drag the appropriate labels to their respective targets. Reset Help Median aperture Interventricular foramen Third ventricle Lateral aperture Cerebral aqueduct Fourth ventricle Lateral ventricle – Type here to search S O – 9
The correct answer and explanation is:
This activity likely refers to labeling the ventricular system of the brain in a diagram of Figure 12.4b, which depicts structures involved in the circulation of cerebrospinal fluid (CSF). Below are the correct labels and their explanations:
Correct Labels:
- Lateral Ventricle – Found in each hemisphere of the brain; they are large C-shaped structures that store and circulate CSF.
- Interventricular Foramen (of Monro) – A channel that connects each lateral ventricle to the third ventricle.
- Third Ventricle – A narrow, slit-like cavity located in the midline of the brain between the two halves of the thalamus.
- Cerebral Aqueduct (of Sylvius) – A narrow canal that connects the third ventricle to the fourth ventricle, running through the midbrain.
- Fourth Ventricle – A diamond-shaped cavity located between the brainstem and the cerebellum, which serves as a passage for CSF to flow into the subarachnoid space.
- Lateral Aperture (of Luschka) – Paired openings on the lateral sides of the fourth ventricle that allow CSF to flow into the subarachnoid space.
- Median Aperture (of Magendie) – An opening on the posterior side of the fourth ventricle that also allows CSF to flow into the subarachnoid space.
Explanation :
The ventricular system of the brain is a network of interconnected cavities filled with cerebrospinal fluid (CSF), which is crucial for cushioning the brain, maintaining intracranial pressure, and removing metabolic waste.
CSF is primarily produced by the choroid plexus located within the lateral ventricles. From here, it flows through the interventricular foramen into the third ventricle, situated at the midline between the thalamic hemispheres. The cerebral aqueduct then channels CSF from the third ventricle to the fourth ventricle, located posterior to the brainstem and anterior to the cerebellum.
The fourth ventricle is the final cavity within the ventricular system before CSF exits into the subarachnoid space. This occurs through three openings: the median aperture and two lateral apertures. These apertures ensure the widespread distribution of CSF around the brain and spinal cord.
The lateral ventricles are the largest and most prominent ventricles, with their curved shapes following the contours of the cerebral hemispheres. The third ventricle and cerebral aqueduct are much narrower, reflecting their roles as passageways. The fourth ventricle’s placement facilitates the transition of CSF from the brain to the spinal cord.
This system plays a critical role in protecting the central nervous system from trauma, providing buoyancy to reduce the effective weight of the brain, and maintaining homeostasis. Understanding this system is vital for identifying conditions like hydrocephalus, which occurs when CSF flow is obstructed.