Exam 3 Practice Quiz

The external auditory meatus is a part of the ear canal, which is located in the temporal bone. This bone is situated on the sides and base of the skull, and it houses important structures such as the ear canal, middle ear, and inner ear. The temporal bone is responsible for protecting these delicate structures and also plays a role in hearing and balance.

The correct answer is choroid plexa. The choroid plexus is responsible for producing cerebrospinal fluid (CSF) in the brain. It is a network of blood vessels located in the ventricles of the brain. The choroid plexus filters blood plasma and secretes CSF, which serves to protect and nourish the brain and spinal cord.

The correct answer is that the CSF from subarachnoid granulations joins the venous blood in the superior sagittal sinus, which flows posteriorly to the confluence of sinuses and follows a path to leave the brain via the internal jugular vein. This is because the superior sagittal sinus is a major dural venous sinus located in the midline of the brain, and it receives blood from the subarachnoid space through the arachnoid granulations. The blood in the superior sagittal sinus then flows posteriorly to the confluence of sinuses, where it merges with other sinuses before leaving the brain through the internal jugular vein.

The subarachnoid granulations are responsible for allowing the cerebrospinal fluid to pass through. These granulations are small, finger-like projections found in the arachnoid mater, one of the layers of the meninges that surround the brain and spinal cord. The cerebrospinal fluid is produced in the ventricles of the brain and circulates around the brain and spinal cord, providing buoyancy and protection. The subarachnoid granulations act as one-way valves, allowing the cerebrospinal fluid to exit the subarachnoid space and enter the venous system, where it is eventually reabsorbed into the bloodstream.

The superior and inferior colliculi are two pairs of small structures located in the midbrain. Together, they are known as the corpora quadrigemina of the tectum. The tectum is the dorsal part of the midbrain and is responsible for processing sensory information, particularly visual and auditory stimuli. The colliculi play a crucial role in coordinating reflex responses to visual and auditory stimuli, such as the startle reflex. Therefore, the correct answer is corpora quadrigemina of tectum.

The cribiform plate is located on either side of the crista galli. The crista galli is a bony ridge that projects upwards from the ethmoid bone, which is located at the midline of the skull. The cribiform plate is a thin, perforated structure that forms the roof of the nasal cavity and allows for the passage of olfactory nerves.

CN V3, also known as the mandibular branch of the trigeminal nerve, innervates the muscles of mastication. These muscles are responsible for the movement of the jaw during chewing and biting. The correct answer, "muscles of mastication," accurately describes CN V3's motor function.

The cerebral aqueduct connects the third and fourth ventricles in the brain. It is a narrow channel that allows cerebrospinal fluid to flow between these two ventricles. The third ventricle is located in the diencephalon, while the fourth ventricle is located in the brainstem. The cerebral aqueduct plays a crucial role in maintaining the circulation and balance of cerebrospinal fluid throughout the brain.

The crista galli is a bony ridge that projects from the ethmoid bone, which is located at the front of the skull between the eye sockets. It serves as an attachment point for the falx cerebri, a fold of the dura mater that helps support and stabilize the brain. The ethmoid bone also contains several other important structures, such as the cribriform plate, which allows for the passage of olfactory nerves involved in the sense of smell. Therefore, the correct answer is ethmoid.

The correct answer is CN I. The olfactory nerve, also known as cranial nerve I, is the only cranial nerve that passes through the cribiform plate. This nerve is responsible for the sense of smell and carries sensory information from the nasal cavity to the brain.

The meningeal artery passes through the foramen spinosum.

The sella turcica is part of the middle cranial fossa. The cranial fossa is the concave base of the skull that houses the brain. It is divided into three regions: anterior, middle, and posterior. The sella turcica is a saddle-shaped depression located in the middle cranial fossa. It houses the pituitary gland and is surrounded by bony structures such as the sphenoid bone.

The prosencephalon is one of the three primary divisions of the embryonic brain. It further develops into two major regions known as the telencephalon and diencephalon. The telencephalon is responsible for higher cognitive functions, such as memory, language, and sensory processing. It includes structures like the cerebral cortex, basal ganglia, and limbic system. On the other hand, the diencephalon plays a crucial role in relaying sensory information and regulating various homeostatic processes. It consists of structures like the thalamus and hypothalamus.

The cerebral aqueduct connects the third and fourth ventricles in the brain. It is a narrow canal that allows cerebrospinal fluid (CSF) to flow between these two ventricles. CSF plays a crucial role in cushioning and protecting the brain, as well as providing nutrients and removing waste products. The cerebral aqueduct is located within the midbrain and is an important pathway for the circulation of CSF throughout the ventricular system.

The superior colliculi is the reflex center for visual stimulation. Located in the midbrain, these structures play a crucial role in directing eye movements and coordinating visual responses. They receive input from the retina and other visual pathways, allowing for the quick and automatic processing of visual information. This reflexive response helps orient our gaze towards visual stimuli and is essential for visual tracking and attention.

The foramen spinosum is a small opening located in the sphenoid bone. It is situated on the lateral aspect of the greater wing of the sphenoid bone, posterior to the foramen ovale. This foramen serves as a passageway for the middle meningeal artery, which supplies blood to the meninges and bones of the cranial vault. Therefore, the correct answer is sphenoid.

The correct answer is "in or on the wall of the target organ." In the parasympathetic division, the post synaptic cell bodies are located either inside or on the wall of the target organ. This is in contrast to the sympathetic division, where the post synaptic cell bodies are located in ganglia. The parasympathetic division is responsible for rest and digest activities, and its nerve fibers innervate specific organs to regulate their functions. Thus, having the post synaptic cell bodies in or on the wall of the target organ allows for more precise control and coordination of parasympathetic responses.

Blockage of the intraventricular foramen or the cerebral aqueduct can result in hydrocephalus. Hydrocephalus is a condition characterized by the accumulation of cerebrospinal fluid in the brain, leading to increased pressure and enlargement of the ventricles. This can cause a variety of symptoms, including headaches, nausea, vomiting, cognitive impairment, and in severe cases, neurological deficits. Treatment for hydrocephalus typically involves the insertion of a shunt to divert the excess fluid and relieve the pressure on the brain.

Ependymal cells are a type of cells that line the ventricles of the brain and aid in the flow of cerebrospinal fluid (CSF). These cells have cilia on their surface, which help in the movement of CSF through the ventricles. The cilia beat in a coordinated manner, creating a flow of CSF that helps in the circulation and distribution of nutrients, removal of waste products, and maintenance of a stable environment for the brain and spinal cord.

The foramen magnum is not in the middle cranial fossa. It is located at the base of the skull, specifically in the posterior cranial fossa. The foramen magnum is a large opening through which the spinal cord passes and connects to the brain. It allows for the passage of important structures such as blood vessels and nerves. The other options listed, including the superior orbital fissure, foramen rotundum, foramen ovale, and optic canal, are all located in the middle cranial fossa.

The hypoglossal canal is a bony canal that runs between the jugular foramen and the foramen magnum. It is located in the base of the skull and allows the passage of the hypoglossal nerve, which is responsible for the movement of the tongue.

The dura mater is the outermost and toughest layer of the cranial meninges. It is composed of two layers: the meningeal layer and the periosteal layer. The meningeal layer of the dura mater is responsible for creating the falx cerebri and other falxes in the brain. These falxes are important structures that help to separate and support different parts of the brain. Therefore, the correct answer is dura mater (meningeal layer).

The correct answer is rhombencephalon. The metencephalon and the myelencephalon are both parts of the rhombencephalon, which is one of the three primary vesicles that develop during early brain development. The prosencephalon, mesencephalon, telencephalon, and diencephalon are all different parts of the brain, but they do not give rise to the metencephalon and myelencephalon.

Cranial nerve IV, also known as the trochlear nerve, is the only cranial nerve that doesn't originate in the pons. It originates in the midbrain, specifically in the trochlear nucleus. The trochlear nerve is responsible for the motor control of the superior oblique muscle, which is involved in eye movement.

In the parasympathetic division, presynaptic fibers are long and postsynaptic fibers are short. This means that the nerve fibers that transmit signals from the central nervous system to the target organs (presynaptic fibers) are longer in length, while the nerve fibers that transmit signals from the target organs back to the central nervous system (postsynaptic fibers) are shorter. This arrangement allows for efficient and coordinated communication between the central nervous system and the organs, enabling the parasympathetic division to regulate bodily functions such as digestion and relaxation.

The parasympathetic division conserves energy by promoting rest and digestion, while the sympathetic division expends energy by activating the fight or flight response.

Cranial nerve XII, also known as the hypoglossal nerve, does not pass through the jugular foramen. The jugular foramen is a large opening in the base of the skull that allows for the passage of important structures such as the internal jugular vein and several cranial nerves. However, cranial nerve XII exits the skull through its own separate opening called the hypoglossal canal, which is located just anterior to the jugular foramen. Therefore, cranial nerve XII does not pass through the jugular foramen.

Cranial nerve VII, also known as the facial nerve, passes through the stylomastoid foramen. This foramen is located in the temporal bone.

The leptomeninx refers to the two innermost layers of the meninges, which are the arachnoid mater and the pia mater. These two layers are located beneath the dura mater and provide protection and support for the brain and spinal cord. The arachnoid mater is a delicate, web-like membrane that lies between the dura mater and the pia mater. The pia mater is a thin, transparent membrane that adheres closely to the surface of the brain and spinal cord, providing nourishment and support. Together, these two layers make up the leptomeninx.

The central sulcus is a prominent fissure that separates the frontal lobe from the parietal lobe in the brain. It runs laterally from the top of the brain to the side, dividing the two lobes. This sulcus is important as it marks the boundary between the primary motor cortex in the frontal lobe and the primary somatosensory cortex in the parietal lobe. It plays a crucial role in motor control and sensory perception.

The central canal continues from the medulla oblongata to the spinal cord. The central canal is a fluid-filled channel that runs through the center of the spinal cord and connects with the ventricular system of the brain. It serves as a pathway for cerebrospinal fluid and is involved in the circulation and distribution of nutrients, hormones, and waste products throughout the central nervous system.

The phrenic nerve is responsible for signaling the diaphragm to breathe. It originates from the cervical spine and travels down to the diaphragm, controlling its movement. When the phrenic nerve is stimulated, it causes the diaphragm to contract, allowing for inhalation and exhalation of air. This nerve plays a crucial role in the respiratory system and is essential for normal breathing.

The cranial nerve V, also known as the trigeminal nerve, does not contain parasympathetic fibers. This nerve is responsible for sensory information from the face and motor functions such as chewing. Parasympathetic fibers are responsible for regulating involuntary functions in the body, such as digestion and heart rate, and they are found in other cranial nerves such as III (oculomotor), VII (facial), IX (glossopharyngeal), and X (vagus). Therefore, the correct answer is V.

The glossopharyngeal nerve innervates the parotid salivary gland. This nerve is responsible for carrying sensory information from the tongue, throat, and the parotid gland. It also controls the motor function of the stylopharyngeus muscle, which helps in swallowing. Therefore, the glossopharyngeal nerve is the correct answer for the innervation of the parotid salivary gland.

The foramen rotundum is not located in the posterior cranial fossa. The posterior cranial fossa is a depression in the base of the skull that contains various openings for nerves and blood vessels. The internal acoustic meatus, hypoglossal canal, foramen magnum, and jugular foramen are all structures that are found in the posterior cranial fossa. However, the foramen rotundum is not located in this region. It is actually located in the middle cranial fossa, which is a different compartment of the skull.

The stylomastoid foramen is not a point where the trigeminal nerve passes through the skull. The trigeminal nerve passes through the superior orbital fissure, foramen ovale, foramen spinosum, and foramen rotunda. The stylomastoid foramen is located in the temporal bone and serves as an exit point for the facial nerve.

The tentorium cerebri is not an infolding of the dura mater. It is a thick, crescent-shaped fold of dura mater that separates the cerebrum from the cerebellum in the brain. The falx cerebelli is an infolding of the dura mater that separates the two cerebellar hemispheres. The sellar diaphragm is a small infolding of the dura mater that covers the sella turcica, a bony structure in the skull. The falx cerebri is a large infolding of the dura mater that runs vertically in the midline, separating the two cerebral hemispheres.

A stroke to the cerebellum can cause ataxia. The cerebellum is responsible for coordinating movement and balance, so damage to this area can result in difficulties with coordination and balance, leading to ataxia. This can manifest as unsteady gait, clumsiness, and difficulty with fine motor skills. Excessive drinking can also cause ataxia by affecting the cerebellum and impairing its function. Therefore, both a stroke to the cerebellum and excessive drinking can lead to ataxia.

The coronal and parietal sutures join at the bregma. The bregma is a point on the skull where the coronal and sagittal sutures intersect. It is located at the anterior fontanelle in infants and typically closes by the age of two. The bregma is an important landmark in neuroanatomy and is used as a reference point for various measurements and surgical procedures.

Cranial nerve V3, also known as the mandibular nerve, does not pass through the cavernous sinus. The cavernous sinus is a large vein-filled space located on each side of the sella turcica, which houses the pituitary gland. Cranial nerves III, V1, and V2 all pass through the cavernous sinus. Cranial nerve V3, however, exits the skull through the foramen ovale and does not enter the cavernous sinus.

The posterior cerebral arteries terminate between the cerebellum and the occipital lobe. These arteries supply blood to the posterior part of the brain, including the occipital lobe which is responsible for visual processing. The termination of these arteries in this specific region ensures that the occipital lobe receives the necessary oxygen and nutrients for its proper functioning.

The viscerocranium is the facial skeleton, which consists of the bones that form the structure of the face. There are a total of 15 bones in the viscerocranium, including the mandible, maxilla, zygomatic bones, nasal bones, and others. These bones are responsible for providing support and protection to the facial organs and also play a crucial role in facial expressions.

The correct answer is ducussation. The fibers of the pyramids cross over at the ducussation, which is a point in the brain where nerve fibers from one side of the body cross over to the opposite side. This crossing over allows for the integration and coordination of sensory and motor information between the two sides of the body.

The visual cortex is responsible for processing visual information. It is located in the occipital lobe, which is situated at the back of the brain. The left occipital lobe specifically processes visual information from the right visual field. Therefore, the correct answer is left occipital lobe.

The parasympathetic ganglion associated with the parotid gland and CN IX is the otic ganglion. The otic ganglion is located near the mandibular division of the trigeminal nerve (CN V3) and is responsible for providing parasympathetic innervation to the parotid gland. This innervation helps regulate the production of saliva in the gland. The other options listed, such as celiac, parotid, glossopharyngeal, and hypoglossal, are not associated with the parotid gland or CN IX.

The lambda is a specific point on the skull where the lambdoid and sagittal sutures intersect. The lambdoid suture is located at the back of the skull, separating the occipital bone from the parietal bones. The sagittal suture runs along the midline of the skull, separating the two parietal bones. Therefore, the correct answer is lambdoid and sagittal, as these are the sutures that meet at the lambda.

The pnemotaxic center is responsible for regulating the rhythm and depth of breathing. It sends inhibitory signals to the inspiratory center, which then tells the body to stop breathing in. This center plays a crucial role in maintaining the balance between inhalation and exhalation, ensuring that the body receives enough oxygen and gets rid of carbon dioxide efficiently. The other options listed are not directly involved in the regulation of breathing.

The correct answer is sensory. The central sulcus is a prominent groove that separates the frontal lobe from the parietal lobe in the brain. The sensory area, also known as the somatosensory cortex, is located posterior to the central sulcus in the parietal lobe. This area is responsible for processing sensory information such as touch, temperature, and pain from different parts of the body.

The cerebral aqueduct, also known as the aqueduct of Sylvius, is a narrow canal that connects the third and fourth ventricles in the brain. It develops from the mesencephalon, which is also known as the midbrain. The mesencephalon is one of the major divisions of the brainstem and plays a crucial role in relaying sensory and motor information.

The pons is the anterior boundary of the fourth ventricle. The fourth ventricle is a fluid-filled cavity located in the brainstem, and it is positioned between the pons and the cerebellum. The pons serves as a bridge connecting different parts of the brain, and it helps relay signals between the cerebrum and the cerebellum. Therefore, it makes sense that the pons would form the anterior boundary of the fourth ventricle.