Otterbein/Grant CRNA A&p Midterm Neuro Review

The brain receives 15% of cardiac output. This means that 15% of the total amount of blood pumped by the heart is directed to the brain. This is because the brain requires a constant supply of oxygen and nutrients to function properly. The brain's high demand for blood is necessary for maintaining its various functions, such as cognition, memory, and motor control.

The oculomotor, trochlear, and abducens cranial nerves are responsible for controlling eye movement. These nerves work together to coordinate the movement of the eye muscles, allowing us to move our eyes in different directions and track objects. Dysfunction or damage to these nerves can result in eye movement disorders such as strabismus or nystagmus. Therefore, eye movement is the correct function controlled by these cranial nerves.

The hypothalamus is responsible for regulating body temperature, water balance, and fat/carbohydrate metabolism. It acts as the control center for these functions by receiving signals from various parts of the body and coordinating appropriate responses. This includes controlling the release of hormones that help regulate body temperature, such as vasopressin and thyrotropin-releasing hormone. Additionally, the hypothalamus plays a crucial role in maintaining water balance by controlling the release of antidiuretic hormone (ADH) and regulating thirst. It also controls the release of hormones that regulate metabolism, such as thyrotropin-releasing hormone and corticotropin-releasing hormone.

Cerebral blood flow changes 5-7% proportionally per 1 degree C change in temperature.

Grey matter is the region of the brain that contains the cell bodies of neurons and is responsible for processing information. CMRO2 refers to cerebral metabolic rate of oxygen consumption, which is a measure of how much oxygen the brain uses. The statement suggests that 80% of CMRO2 is attributed to grey matter, meaning that a significant amount of oxygen consumption in the brain is due to the metabolic activities of grey matter. Therefore, the statement is true.

The major commissure connecting cerebral hemispheres is the corpus callosum. It arches above structures of the diencephalon and forms a roof over the lateral ventricle. The parietal lobe is not the correct answer as it is a specific region of the cerebral cortex involved in sensory processing. The midpons and brainstem are also not the correct answers as they are structures located in the brainstem, not involved in connecting the cerebral hemispheres.

Cells that act as gates determine which action potentials are transmitted to the central nervous system (CNS) for perception. These gates can open or close based on various factors, such as the strength of the stimulus or the presence of inhibitory signals. By selectively allowing certain action potentials to pass through, gates help regulate the flow of information to the CNS, ensuring that only relevant signals are transmitted for perception.

The cerebellum is a crucial part of the brain that is responsible for coordinating muscle activity and maintaining balance and equilibrium. When there is an injury or infarct in the cerebellum, it can have a devastating impact on these life functions. This is because the cerebellum plays a vital role in ensuring smooth and coordinated movements, as well as maintaining posture and balance. Therefore, the statement that cerebellar injury/infarct is devastating to life functions is true.

The cranial nerves are a set of 12 pairs of nerves that originate from the brain and control various functions of the head and neck. The optic nerve (II) is responsible for transmitting visual information from the eye to the brain, while the olfactory nerve (I) is responsible for the sense of smell. Unlike the other cranial nerves, which originate from the brainstem, the optic and olfactory nerves originate directly from the brain itself. Therefore, the correct answer is that the optic (II) and olfactory (I) nerves do not originate from the brainstem.

Shivering is a physiological response in which the body rapidly contracts and relaxes muscles to generate heat. This heat production is necessary to maintain body temperature when exposed to cold environments. Shivering involves increased muscle activity, which in turn increases the demand for oxygen to fuel the muscle contractions. This increased demand for oxygen can cause the body's oxygen consumption to rise by 200-400%.

Cerebral perfusion pressure refers to the pressure needed to ensure adequate blood flow to the brain. If this pressure drops below 25 mmHg, it can lead to irreversible brain damage. This is because the brain requires a constant supply of oxygen and nutrients, which are delivered through blood flow. When the cerebral perfusion pressure falls below this threshold, it indicates that there is insufficient blood flow to the brain, causing damage to the brain tissue. Therefore, maintaining a cerebral perfusion pressure above 25 mmHg is crucial to prevent irreversible brain damage.

The correct answer is Adrenal medulla and Sweat glands. The adrenal medulla is a part of the adrenal gland that secretes hormones directly into the bloodstream, rather than through a synapse. These hormones, such as adrenaline, do not rely on adrenergic neurotransmitters for their effects. Sweat glands, on the other hand, are innervated by the sympathetic nervous system (SNS), but they do not have adrenergic neurotransmitters. Instead, they release acetylcholine, which activates sweat production. The other options, Hepatic vein and Ovaries, are not related to the SNS or adrenergic neurotransmitters.

A-alpha fibers are the largest nerve fibers with the fastest conduction velocity. They are found in muscle spindle afferents and golgie tendon organs. These fibers are responsible for transmitting sensory information related to muscle stretch and tension. A-alpha fibers are involved in proprioception, allowing us to have a sense of where our body is in space and to maintain balance and coordination.

The anterior hypothalamus is responsible for monitoring and regulating body temperature. It receives information about the core temperature of the body and compares it to the set-point temperature, which is the ideal temperature that the body strives to maintain. If the detected core temperature deviates from the set-point temperature, the anterior hypothalamus initiates appropriate responses to restore the body temperature back to the set-point. Therefore, it can be concluded that the statement is true.

Mnemonic that kind of helps:

Lady Monro had 3 aqueducts that led to 4 luscious and magical subarachnoid spaces.

The movement of substances across the blood-brain barrier (BBB) is regulated by various factors such as size, charge, lipid solubility/protein binding. However, the oil:gas coefficient is not a determinant of the substance's movement across the BBB. The oil:gas coefficient is a measure of a substance's solubility in oil compared to its solubility in gas, and it does not directly impact the ability of a substance to cross the BBB. Therefore, the oil:gas coefficient is not a factor governing the movement of substances across the BBB.

The cauda equina is located distal to the L2 vertebrae in adults. The cauda equina is a collection of nerve roots that extend below the spinal cord and resembles a horse's tail. It is situated in the subarachnoid space, which is the area between the arachnoid mater and pia mater layers of the meninges. The L2 vertebra is the second lumbar vertebra and is located in the lower back region.

The rate of utilization of oxygen by the brain tissue remains approximately 3.5 mL O2/100g/min, except during periods of intense brain activity. This means that under normal conditions, the brain utilizes oxygen at a consistent rate of 3.5 mL per 100 grams of brain tissue per minute. This rate may increase during periods of intense brain activity when the brain requires more oxygen for optimal functioning.

Hydrogen ions have been shown to cause vasodilation of the cerebral vessels, leading to an increase in cerebral blood flow. This is supported by scientific evidence that demonstrates the role of hydrogen ions in regulating blood vessel diameter. Therefore, it can be concluded that the statement is true.

Patients with chronic HTN will have an autoregulation curve shift to the left. This statement is not true because in patients with chronic hypertension, the autoregulation curve actually shifts to the right. Chronic hypertension leads to vascular remodeling and narrowing of the cerebral blood vessels. As a result, the autoregulation curve shifts to the right, meaning that higher arterial pressures are required to maintain a constant cerebral blood flow.

The structures mentioned in the question, including the cerebellum, brain stem, midbrain, pons, and medulla oblongata, are located below the tentorium cerebelli, a structure that separates the cerebrum from the cerebellum. Therefore, they are considered infratentorial structures.

Other characteristics
pH 7.32
specific gravity 1.002-1.009
Measure of number or solutes in a substance compared to water
isotonic w/plasma
Normal CSF pressure is 5-15 mmHg

Composition
> plasma – Na Cl Mg

The presynaptic neuronal cell bodies of the sympathetic nervous system are located in the lateral horns of gray matter of the spinal cord between T1-L2 cord levels.

Radiation accounts for 60% of heat loss for patients in the operating room. This means that a significant portion of the heat lost by patients during surgical procedures is due to radiation. It is important for healthcare providers to be aware of this fact and take necessary measures to prevent excessive heat loss, such as using warming blankets or adjusting the room temperature, to ensure patient comfort and safety during procedures.

Starts at 50 mmHg but more rapid increase at 30

Gray matter contains neuron bodies and processes/responds to stimuli.

This describes the posterior circulation.
Anterior circulation is provided by the carotids.

Prostaglandins are a type of pyrogen, which means they can cause fever. The production of prostaglandins is inhibited by ASA (aspirin) and steroids. This means that when ASA and steroids are present, the production of prostaglandins is reduced, leading to a decrease in fever.

The correct answer is Averages 50-60 mL/100 g/min, 750-900 mL/min, 15% of cardiac output. Cerebral blood flow refers to the amount of blood that is delivered to the brain per unit of time. It is typically measured in milliliters per 100 grams of brain tissue per minute. On average, the cerebral blood flow is around 50-60 mL/100 g/min. In terms of total blood flow, the brain receives approximately 750-900 mL of blood per minute, which accounts for about 15% of the cardiac output. The statement that cerebral blood flow is not affected by anesthetic drugs is not accurate, as certain anesthetics can indeed alter cerebral blood flow.

The brainstem is a vital part of the central nervous system, connecting the brain to the spinal cord. It consists of the midbrain, pons, and medulla oblongata. The midbrain is responsible for relaying sensory information and controlling certain motor functions. The pons acts as a bridge between different parts of the brain, facilitating communication. The medulla oblongata controls essential functions such as breathing, heart rate, and blood pressure. The basal ganglia, however, is not a part of the brainstem. It is a group of structures located deep within the brain that plays a role in motor control and movement coordination.

Substance P and glutamate are both neurotransmitters that directly activate nociceptors. Nociceptors are sensory neurons that transmit pain signals to the brain. Substance P is released in response to tissue injury or inflammation and is involved in the transmission of pain signals. Glutamate is the primary excitatory neurotransmitter in the central nervous system and plays a crucial role in pain perception. Serotonin and GABA are not directly involved in activating nociceptors and do not have a direct role in the transmission of pain signals.

This describes the medulla oblongata.

Pons- means “bridge”, connected to cerebrum by cerebral peduncles (fibers in midbrain), motor and sensory fibers connecting brain with lower CNS centers

The term "stump" refers to the residual portion of an organ or structure that remains after a surgical procedure. In the context of the given question, "stump" is the correct answer because it is the only option that is related to the topic of the question. The question is asking about the pressure transmitted through the Circle of Willis back to the carotid artery, specifically in the context of endarterectomy. The statement that ">60 mmHg is normal and acceptable" suggests that the pressure being referred to is likely related to the stump of the carotid artery after endarterectomy.

ASA, NSAIDs, and specific cyclooxygenase inhibitors exert analgesic effects by inhibiting prostaglandin synthesis. Prostaglandins are lipid compounds that play a role in the inflammatory response and pain signaling. Cyclooxygenase is an enzyme involved in the production of prostaglandins. By inhibiting cyclooxygenase, these medications prevent the synthesis of prostaglandins, leading to a reduction in inflammation and pain.

Basal ganglia are clusters of neuron cell bodies that are located deep within the white matter of the brain. They are responsible for producing dopamine, which is a neurotransmitter involved in various functions including movement. Basal ganglia flank the lateral and third ventricles, and they are part of the extrapyramidal system (EPS), which is involved in regulating motor activities.

Anesthetics inhibit vasoconstriction and shivering 3x as much as they restrict sweating, not necessarily causing vasodilation.