Human Anatomy Quiz Chapter 11

The gag reflex is a protective mechanism that prevents choking by triggering the contraction of the muscles in the back of the throat. When an object or food stimulates the sensitive tissues in the back of the throat, the gag reflex is activated, causing a person to cough or gag in order to expel the foreign object. If the gag reflex is not working properly or is absent, the person may be at risk of choking on their food as the protective mechanism to remove the obstruction is compromised.

The ulnar, radial, and median nerves are responsible for supplying the forearm and hand. These nerves innervate the muscles and provide sensory information to these areas, allowing for movement and sensation. The other options, such as breathing muscles, jaw, and hip and thigh, are not innervated by these specific nerves.

The vagus nerve, also known as the tenth cranial nerve, is responsible for innervating the heart and gastrointestinal systems. It is called the "wandering" nerve because it extends outside the head area and travels to various organs in the body. The vagus nerve plays a crucial role in regulating heart rate, controlling digestion, and influencing various other bodily functions.

The baroreceptor reflex is concerned with the regulation of blood pressure. Baroreceptors are sensory receptors located in the walls of blood vessels and the heart. They detect changes in blood pressure and send signals to the brain to initiate appropriate responses to maintain blood pressure within a normal range. This reflex helps to regulate blood pressure by adjusting heart rate, blood vessel constriction or dilation, and fluid balance in the body.

The Babinski reflex is stimulated by stroking the sole of the foot with a sharp object. This reflex is characterized by the extension of the big toe and fanning out of the other toes in response to the stimulation. It is a normal reflex in infants, but in adults, it may indicate an underlying neurological disorder. The patellar reflex, baroreceptor reflex, and gag reflex are not specifically related to the stimulation of the sole of the foot with a sharp object.

The gag reflex is a protective mechanism that helps prevent choking by triggering the contraction of muscles in the throat. This reflex is mediated by the glossopharyngeal nerve, which is responsible for transmitting sensory information from the back of the throat to the brain. When the glossopharyngeal nerve is stimulated by an object touching the back of the throat, it sends signals to the brain to initiate the gag reflex. Therefore, the correct answer is the glossopharyngeal nerve.

The sciatic nerve is the largest nerve in the body and runs from the lower back down the back of each leg. Damage to this nerve can result in a condition called sciatica, which can cause pain, weakness, and numbness in the lower back, buttocks, and legs. Since the question states that damage to this nerve prevents extension of the hip and flexion of the knee, it is clear that the correct answer is sciatic.

A lumbar puncture is a procedure where a needle is inserted into the subarachnoid space, which is the space between the arachnoid mater and the pia mater in the spinal cord. This is done to collect cerebrospinal fluid (CSF) for diagnostic purposes. The dural sinus is a blood vessel located within the dura mater, the central canal is a narrow channel within the spinal cord, and arachnoid villi are small projections of the arachnoid mater that absorb CSF into the bloodstream. Therefore, the correct answer is the subarachnoid space.

The correct answer is "vestibulocochlear." Cranial nerve VIII, also known as the vestibulocochlear nerve, is responsible for transmitting sensory information related to hearing and balance from the inner ear to the brain. It is not a motor nerve or a spinal nerve, and it is not concerned with vision.

Novocain is a local anesthetic commonly used for spinal anesthesia. It is injected into the subarachnoid space, which is the area between the arachnoid mater and the pia mater surrounding the spinal cord. This space contains cerebrospinal fluid and is where the nerves of the spinal cord are located. By injecting Novocain into the subarachnoid space, it can effectively block nerve impulses and provide anesthesia to the lower part of the body. The other options, such as the lateral ventricle, central canal, and dorsal root ganglia, are not appropriate sites for spinal anesthesia.

The phrenic nerve is most descriptive as a motor nerve supplying the diaphragm. It is responsible for controlling the movement of the diaphragm, which is the main muscle involved in breathing. This nerve plays a crucial role in the process of respiration by transmitting signals from the brain to the diaphragm, allowing it to contract and relax.

The hypoglossal nerve is responsible for controlling the movement of the tongue. When evaluating this cranial nerve, the nurse asks the person to stick out their tongue and observes for any deviation in its position. If there is any abnormality or deviation in the position of the protruded tongue, it may indicate dysfunction or damage to the hypoglossal nerve. The other options (trigeminal, facial, and olfactory) are not directly involved in controlling tongue movement, making hypoglossal the correct answer.

The oculomotor, trochlear, and abducens cranial nerves are responsible for innervating the extrinsic eye muscles, which allows for the movement of the eyeball. These muscles control the various movements of the eye, such as looking up, down, left, and right. Therefore, the correct answer is that these cranial nerves innervate the extrinsic eye muscles to move the eyeball.

A spinal cord injury at the level of C2 causes quadriplegia, which is the paralysis of all four limbs. Additionally, it also results in an inability to breathe due to the involvement of the phrenic nerve, which controls the diaphragm, the main muscle responsible for breathing. This injury affects the cervical region of the spinal cord, which is higher up in the neck, leading to more severe consequences such as paralysis and respiratory impairment.

The sciatic nerve is the largest nerve in the body and runs from the lower back down the back of the leg. It is responsible for providing motor and sensory function to the leg and foot. When giving an intramuscular injection into the buttocks, it is important to avoid injuring the sciatic nerve, as this can cause pain, numbness, and difficulty walking. Therefore, the injection is given in the upper outer quadrant of the buttocks to minimize the risk of hitting the sciatic nerve.

A motor tract refers to a pathway in the nervous system that carries signals from the brain to the muscles, enabling voluntary movement. The spinothalamic tract is responsible for transmitting sensory information related to pain and temperature. An ascending tract carries sensory information from the body to the brain, while a descending tract carries motor commands from the brain to the muscles. Gray matter refers to regions of the central nervous system that primarily consist of cell bodies and dendrites. Therefore, the best description of a motor tract is a descending tract.

The olfactory nerve is primarily responsible for the sense of smell, making it least descriptive to say that it moves the tongue. The olfactory nerve is a sensory cranial nerve (cranial nerve I) that transmits information about odors from the nose to the brain. It does not have any motor function related to moving the tongue.

The Babinski reflex is a neurologic reflex that is elicited by stroking the sole of the foot. This reflex is commonly seen in infants and is characterized by the extension of the big toe and fanning out of the other toes in response to the stimulus. The presence of the Babinski reflex in adults can indicate a neurological disorder or damage to the central nervous system.

The baroreceptor reflex is responsible for controlling blood pressure. Baroreceptors are sensory receptors located in the walls of blood vessels, particularly in the carotid sinus and aortic arch. They detect changes in blood pressure and send signals to the brain, which in turn regulates heart rate and blood vessel constriction or dilation to maintain blood pressure within a normal range. This reflex helps to ensure that blood flow and oxygen delivery to tissues and organs remain constant despite changes in posture or other factors that may affect blood pressure.

Damage to cranial nerve II, also known as the optic nerve, can cause blindness. The optic nerve is responsible for transmitting visual information from the retina to the brain. If this nerve is damaged, it can disrupt the communication between the eye and the brain, leading to vision loss or blindness. Therefore, cranial nerve II is the correct answer in this case.

The ankle-jerk reflex is the correct answer because when the Achilles tendon is struck by a hammer, it causes a stretch reflex in the ankle muscles. This reflex is known as the ankle-jerk reflex and is characterized by a quick contraction of the calf muscles, causing the foot to jerk or kick. This reflex is a protective mechanism that helps maintain balance and stability while standing or walking. The other options, such as the Babinski reflex, baroreceptor reflex, and patellar tendon reflex, are not directly related to the Achilles tendon or the stretch reflex caused by striking it with a hammer.

A dermatome is an area of skin that is innervated by a single spinal nerve. Each spinal nerve supplies sensory information to a specific region of the body's surface. Therefore, the correct answer is dermatome.

The pyramidal tract is a major motor tract in the central nervous system. It is responsible for carrying motor signals from the brain to the spinal cord and controls voluntary movements of the body. This tract plays a crucial role in coordinating muscle movements and is involved in fine motor control. The other options listed, such as the cauda equina, spinocerebellar, and spinothalamic tracts, are not major motor tracts but instead serve different functions in the nervous system.

Damage to the common peroneal nerve can lead to footdrop. The common peroneal nerve is responsible for controlling the muscles that lift the foot and toes. When this nerve is damaged, it can result in weakness or paralysis of these muscles, causing difficulty in lifting the foot and making it difficult to walk. This condition is known as footdrop.

The trigeminal nerve is the correct answer because it is a mixed nerve that carries sensory information from the scalp, face, and teeth. It is responsible for detecting sensations such as touch, pain, and temperature in these areas. The olfactory nerve is responsible for the sense of smell, the facial nerve controls facial movements and sensations, and the vestibulocochlear nerve is responsible for hearing and balance.

The optic nerve is responsible for transmitting visual information from the retina to the brain, allowing us to perceive and interpret visual stimuli. It is a sensory nerve and part of the cranial nerves, which control various functions in the head and neck. However, the optic nerve does not have a direct role in moving the eyeball. This function is primarily controlled by the extraocular muscles, which are innervated by other cranial nerves.

Antibiotic-induced ototoxicity refers to damage caused to the inner ear by certain antibiotics. The vestibulocochlear nerve is responsible for transmitting auditory and balance information from the inner ear to the brain. Therefore, it is the nerve that would be damaged in this scenario. Cranial nerve X, also known as the vagus nerve, is responsible for controlling various functions in the body, such as heart rate and digestion. The facial nerve (cranial nerve VII) is responsible for controlling the muscles of the face. Cranial nerve II, also known as the optic nerve, is responsible for transmitting visual information from the eye to the brain.

The cauda equina is a bundle of nerves that extends from the end of the spinal cord. It is located within the spinal cavity, specifically in the lower part of the vertebral column. The cervical plexus, brachial plexus, and vagus nerve are also nerves, but they are not located within the spinal cavity.

The words "spinothalamic," "pyramidal," and "corticospinal" all refer to different types of nerve tracts in the body. These tracts are pathways that carry information or signals from one part of the body to another. Therefore, the word "tracts" is the best description for these terms as it encompasses the concept of nerve pathways.

Ptosis of the eyelid and dilated and fixed pupils are symptoms commonly associated with damage or pressure on the oculomotor nerve. The oculomotor nerve controls the movement of the eyelid and the constriction of the pupil. Damage or pressure on this nerve can result in the eyelid drooping (ptosis) and the pupils becoming dilated and fixed. The optic nerve, on the other hand, is responsible for transmitting visual information from the eye to the brain and is not directly involved in controlling eyelid movement or pupil constriction. Therefore, the correct answer is oculomotor.

The pyramidal tract, also known as the corticospinal tract, originates in the pyramidal cells of the medulla oblongata and carries information to the parietal lobe. This tract is responsible for voluntary motor control, allowing us to consciously control our movements. It is called the corticospinal tract because it originates in the cerebral cortex and travels down the spinal cord, influencing motor neurons that control skeletal muscles throughout the body.

The pudendal nerve is often anesthetized for the purpose of childbirth. This nerve provides sensation to the lower part of the vagina, the perineum, and the rectum. By blocking the pudendal nerve, pain during childbirth can be reduced or eliminated, allowing for a more comfortable experience for the mother.

A "dilated and fixed" pupil is indicative of pressure on cranial nerve III, also known as the oculomotor nerve. This nerve controls the movement of the eye muscles, including the muscles that control the size of the pupil. When there is pressure on cranial nerve III, it can cause the pupil to become dilated and fixed, meaning it does not respond to changes in light. This can be a sign of a serious condition, such as a brain injury or aneurysm, and should be evaluated by a medical professional.

Damage to the sciatic nerve can cause crutch palsy. The sciatic nerve is the longest nerve in the body and runs from the lower back, through the buttocks, and down the back of each leg. It controls the muscles of the lower leg and provides sensation to the back of the thigh, calf, and foot. Crutch palsy, also known as radial nerve palsy, is a condition that occurs when the sciatic nerve is compressed or injured, leading to weakness or paralysis of the leg muscles.