The Brain

How many major regions are contained within the diencephalon?

3, The diencephalon consists of 3 regions, the thalamus, the epithalamus, and the hypothalamus.

The meninges consist of ___ layers.

3, The dura mater, arachnoid, and pia mater make up the 3 layers of the meninges.

How many regions make up the brain stem?

3, the brain stem consists of the midbrain, pons, and medulla oblongata.

Which ventricle is located within the brain stem?

4th ventricle, The fourth ventricle is located anterior to the cerebellum. It is continuous with the third ventricle through the cerebral aqueduct at its superior border and continuous with the central canal at its inferior border.

Where is the arbor vitae located?

Cerebellum, The white matter in the cerebellum has a branching arrangement that resembles a tree. This structure is named for its appearance. The term arbor vitae means "tree of life."

Identify cranial nerve I.

Cranial nerve I is the olfactory nerve.

Which of the following is the outer layer of the meninges?

Dura Mater, The outer layer of the meninges is the dura mater. The dura mater is easily seen surrounding the outside of the brain.

The cerebellum is present on the ventral surface of the sheep brain.

False, The cerebellum is not a ventral structure. It is located on the dorsal surface of the brain.

The pineal body secretes melanocyte stimulating hormone (MSH).

False, The pineal body secretes the hormone melatonin which is secreted when light is not entering the eyes (typically at night).

The brain is a solid organ that lacks cavities.

False, the brain is not completely solid; it contains cavities called ventricles.

What type of tissue makes up the cerebral cortex?

Gray Matter, The cerebral cortex is composed of gray matter. Gray matter is primarily neuron cell bodies.

What area of the brain is in contact with the spine?

Medulla oblongata, this is the lowest region of the brain stem. It is continuous with the spinal cord at the foramen magnum of the skull.

Which region contains the corpora quadrigemina?

Midbrain, The corpora quadrigemina are found on the posterior surface of the midbrain. They can be observed by looking into the transverse fissure.

Which of the following structures is not part of the central nervous system?

Optic Nerve, Nerves are bundles of axons found in the peripheral nervous system. The optic nerve is an extension of the brain, not part of the brain.

Which of the following areas form the central core of the brain?

Thalamus, The thalamus is the central region of the diencephalon and forms the central core of the brain. The thalamus is enclosed by the cerebrum

Identify the passageway found in the spinal cord that is continuous with the ventricles.

The central canal, is the canal found in the spinal cord that originates off of the fourth ventricle.

Which passageway connects the third and fourth ventricles?

The cerebral aqueduct, is the narrow passageway that connects the third and fourth ventricles. It can sometimes be observed on a midsagittal section.

Which region of the brain contains gyri and sulci?

The cerebral cortex, has a convoluted surface. The ridges are known as gyri and the grooves that separate the gyri are sulci.

Which region of the brain is necessary for consciousness?

The cerebrum, is involved in higher order functions such as consciousness, personality, and intellect.

What structure connects the right and left cerebral hemispheres?

The corpus callosum, is a large fiber tract of axons connecting the right cerebral hemisphere to the left cerebral hemisphere.

Which of the following regions cannot be observed superficially?

The diencephalon, forms the central core of the brain and cannot be seen from the surface of the brain.

Which region of the diencephalon contains the pineal body?

The epithalamus, is a region posterior to the thalamus that contains the pineal body.

Which part of the diencephalon is connected to the pituitary gland?

The hypothalamus, is connected to the pituitary gland by the infundibulum.

Which of the following structures attach the pituitary gland to the brain?

The infundibulum, attaches the pituitary gland to the hypothalamus. It contains axons that originate in the hypothalamus and end in the posterior pituitary.

Which ventricles are divided by the septum pellucidum?

The lateral ventricles, are cavities within the cerebrum. The right and left lateral ventricles are separated on midline by the septum pellucidum.

Which of the following ventricles is found under the corpus callosum?

The lateral ventricles. lie side by side under the corpus callosum, separated by the septum pellucidum.

Which of the following landmarks divides the cerebrum in half?

The longitudinal fissure, is easily observed right along midline dividing the cerebrum into the right and left cerebral hemispheres.

Name the membranous encasement surrounding the brain.

The meninges, encase the central nervous system.

Which of the following areas takes visual information from one side of the body and conveys it to the opposite side?

The optic chiasm, is where the optic nerves cross midline, so that sensory information from one side of the body is processed on the opposite side of the brain.

Which of the following glands can be observed on the ventral surface of the sheep brain?

The pituitary gland, can be seen on the ventral surface of the brain. It can easily be removed with the meninges if care isn't taken to keep it attached.

What part of the corpora quadrigemina is clearly observed in a midsagittal section?

The superior colliculus, is clearly observed in the transverse fissure on the back of the midbrain. It is involved with directing eye movement.

Which region acts as a relay center for sensory messages ascending to the cerebrum?

The thalamus, acts as a filter, sending the most important sensory messages on to the correct location in the cerebrum.

Which of the following landmarks separate the cerebrum from the cerebellum?

The transverse fissure is the separation found between the cerebrum and the cerebellum.

What is the function of white matter?

Transmits Messages, White matter is predominately myelinated axons, which transmit information (action potentials).

All three regions of the brain stem can be observed on the ventral surface of the brain.

True, All 3 regions of the brain stem, the midbrain, pons, and medulla oblongata, can be observed on the ventral surface.

The composition of gray matter includes neuron cell bodies.

True, Gray matter consists of neuron cell bodies, unmyelinated axons, and neuroglial cells.

The ventricles are all interconnected.

True, Narrow passageways connect the ventricles together, so that cerebrospinal fluid flows freely inside the ventricular system.

Cerebrospinal fluid is produced within the ventricles.

True, The choroid plexus produces cerebrospinal fluid. It is found in each of the ventricles.

The inferior colliculi are part of the corpora quadrigemina.

True, The corpora quadrigemina is a collection of 4 bumps on the posterior surface of the midbrain. It is composed of the 2 superior colliculi and the 2 inferior colliculi.

The diencephalon is found in between the brain stem and the cerebrum.

True, The diencephalon forms the core of the brain, housed between the cerebrum and brainstem.

The foramen magnum marks the border between the medulla oblongata and spinal cord.

True, The medulla oblongata is the lowest region of the brain stem. It is continuous with the spinal cord at the foramen magnum of the skull.

White matter has a fatty consistency.

True, White matter consists mainly of myelinated axons. Myelination is created by the membrane of a neuroglial cell wrapping many times tightly around an axon. Recall the plasma membrane is a lipid bilayer, therefore white matter contains a lot of fat. The high amount of fat gives white matter it's characteristic glossy white appearance.