Question

True or False:

T or F - Choroid plexuses are found only in the lateral ventricles of the brain.

T or F - A lumbar spinal tap involves the removal of CSF from the epidural space.

T or F -  The “gateway to the brain” is the medulla oblongata.

T or F - A patellar reflex involves interneurons in several segments of the spinal cord.

Answer 1

Answer:

Answer 1. False

Explanation: Choroid plexus is a group of the neurons which are found within all the ventricles of the brain; that is the four ventricles namely; the 2 lateral ventricles, 3rd, and the 4th ventricle.

Their function is to release the CSF (Cerebrospinal fluid) which circulates throughout the brain and the spinal cord and performs a number of functions like;

a) Providing protection to the brain and spinal cord

b) Maintaining buoyancy

c) Shock absorber

d) Help regulate metabolic processes of the brain by participating in the homeostasis and many others

Thus, the given statement is false that they are confined only in the lateral ventricles of the brain.

Answer 2. False

Explanation: Spinal cord is a component of the central nervous system which is lodged inside the vertebral column also commonly called as the bony box. The spinal cord remains covered by three meninges/protective coverings; (from outer to inner)

Outer most duramater

Middle most Arachnoid membrane and

Inner most pia mater

Outer most duramater in turn remains covered by the vertebral column, and the space between the two is called as the epidural space. Similarly the space between the piamater and the arachnoid membrane is called as the sub arachnoid space. It remains filled with the fluid called as the Cerebrospinal fluid.

Furthermore, spinal tap is defined as the condition of puncturing of the spinal cord to extract cerebrospinal fluid in order to have to know about spinal abnormalities if any. Since CSF is present in between the sub arachnoid space, the puncture has to be done at that level. Hence the statement is false that a spinal tap involves the removal of CSF from the epidural space.

Answer 3. False

Explanation: Gateway refers to as the entry point within an organ in order to maintain an effective communication with the other parts of the brain. In case of human brain, the brain stem that is the mid brain (corpora quadrigemina, crura cerebri) along with Pons varolii, and medulla oblongata are considered to be the gateway to the human brain. Thus, alone medulla oblongata is not the only gateway to the brain. It is the last part of the hind brain from where the spinal cord begins and the opening within the skull is called as the foramen magnum.

Answer 4. False

Explanation: Patella is the knee cap bone and the reflex action mediated there is called as the patellar reflex arc.

Reflex action is a process which involves the cooperation of the spinal cord and sensory, relay/association neurons to that of the motor neurons. While the sensory neurons bring in the information towards the spinal cord for processing, it is picked by the association neurons, and the processed information is passed on to the motor neurons which are carried till the effectors.

However, an exception to this is a classic case of the patellar reflex action. It is an example of the monosynaptic reflex action which means there is no involvement of interneuron. Directly the sensory neurons synapses with the motor neurons thereby mediating an action leading to the muscle contraction over the patella /knee cap bone leading to its bending.