Practice Quiz For A&p II (Ans, Senses, And Endocrine)

The term "aqueous humor" refers to a gelatinous fluid that is constantly produced and recycled. This fluid fills the posterior chamber of the eye and helps maintain its shape and nourish the surrounding tissues. It also plays a role in regulating intraocular pressure.

Peptide hormones are composed of amino acids because they are chains of amino acids linked together. These hormones are synthesized in the body by joining specific amino acids in a particular sequence, forming a peptide bond. This structure allows peptide hormones to interact with specific receptors on target cells, triggering various physiological responses. Therefore, the correct answer is that peptide hormones are composed of amino acids.

The adrenal medulla is responsible for producing the hormones epinephrine and norepinephrine. These hormones are part of the body's response to stress and play a role in the fight-or-flight response. Epinephrine and norepinephrine increase heart rate, constrict blood vessels, and elevate blood sugar levels, preparing the body for physical activity. They are also involved in regulating blood pressure and the body's overall response to stress.

The cones in our eyes are responsible for detecting different wavelengths of light, which we perceive as different colors. The three primary colors of light are red, green, and blue. By combining these three colors in different intensities, we can create a wide range of colors. Therefore, the correct answer is red, green, and blue because these are the three colors that our cones are sensitive to.

Preganglionic neurons of the sympathetic nervous system are located in the lateral gray horns of segments T1 to L2 of the spinal cord. This is because the sympathetic nervous system is responsible for the "fight or flight" response, which involves activating the body for action. The lateral gray horns of the spinal cord contain the cell bodies of preganglionic neurons that send signals to the sympathetic ganglia, which then relay the signals to the target organs. Segments T1 to L2 of the spinal cord correspond to the thoracic and upper lumbar regions, where the sympathetic ganglia are located.

The vagus nerves provide preganglionic parasympathetic innervation to structures in the neck and in the thoracic and abdominopelvic cavities.

The gelatinous material found in the posterior cavity is called the vitreous humor. The vitreous humor is a clear, jelly-like substance that fills the space between the lens and the retina in the eye. It helps maintain the shape of the eye and provides support to the delicate structures within the eye, such as the retina. It also helps transmit light to the retina, allowing for clear vision. The other options listed, such as aqueous humor, ora serrata, perilymph, and posterior cavity, are not correct as they do not refer to the gelatinous material found in the posterior cavity.

The pituitary gland consists of two lobes: the anterior lobe and the posterior lobe. The anterior lobe produces six hormones: growth hormone, adrenocorticotropic hormone, thyroid-stimulating hormone, luteinizing hormone, follicle-stimulating hormone, and prolactin. The posterior lobe produces two hormones: oxytocin and antidiuretic hormone. Therefore, the two lobes of the pituitary gland together produce a total of nine hormones.

Autonomic tone is important for ANS function because it allows ANS neurons to increase or decrease their activity, providing a range of control options. This means that the ANS can respond to changing conditions and maintain homeostasis by either increasing or decreasing its activity as needed. It allows for flexibility and adaptability in regulating various bodily functions such as heart rate, blood pressure, digestion, and respiratory rate.

The human lens focuses light on the photoreceptor cells by changing shape. When the ciliary muscles surrounding the lens contract or relax, the shape of the lens changes, allowing it to adjust the focal length and focus the incoming light onto the retina. This process, known as accommodation, is essential for clear vision at different distances.

The statement "there is always a synapse in a peripheral ganglion between the CNS and the effector organ" is true for both the parasympathetic and sympathetic nervous systems. In both systems, there is a two-neuron pathway that includes a synapse in a peripheral ganglion. This synapse helps transmit signals from the central nervous system (CNS) to the effector organ, allowing for coordinated responses in various physiological processes.

When a catecholamine or peptide hormone binds to receptors on the surface of a cell, it triggers a signaling cascade that leads to the production of a second messenger in the cytoplasm. This second messenger acts as a signaling molecule, relaying the message from the hormone receptor complex to various intracellular targets, such as enzymes or ion channels, to initiate a cellular response. The second messenger amplifies the signal and allows for a rapid and coordinated cellular response to the hormone stimulation.

Retinal is a pigment synthesized from vitamin A. It is a key component of rhodopsin, a photosensitive pigment found in the rods of the retina. When light hits rhodopsin, it causes retinal to undergo a conformational change, triggering a cascade of events that ultimately leads to the generation of electrical signals in the retina and the perception of light. Opsin is a protein that combines with retinal to form rhodopsin, and transducin is a protein involved in the signal transduction pathway of rhodopsin.

Increased heart rate when you see a person you fear would be an example of higher-level control of autonomic function because it involves the activation of the sympathetic nervous system, which is responsible for the "fight or flight" response. This response is controlled by higher brain centers, such as the amygdala, which processes fear and triggers the release of stress hormones, leading to an increased heart rate. This response is not reflexive and can be influenced by conscious thoughts and emotions.

Parasympathetic functions are responsible for conserving energy and promoting rest and digest activities in the body. These functions include decreasing the rate of cardiac contraction, constriction of the pupils, stimulation of urination, and stimulation of defecation. However, dilation of the airways is not a parasympathetic function. Instead, it is a sympathetic function, which is responsible for the fight or flight response and increases the diameter of the airways to facilitate increased airflow during times of stress or exercise.

Preganglionic fibers leave the central nervous system (CNS) and then synapse on ganglionic neurons. Ganglionic neurons are located in peripheral ganglia and are responsible for relaying signals from the CNS to the target organs or tissues. This synapse allows for the transmission of information and coordination of visceral reflex responses, such as regulating heart rate or digestion. Motor neurons, on the other hand, are responsible for transmitting signals from the CNS to the muscles, while sensory neurons transmit signals from sensory organs to the CNS.

The ciliary body is responsible for changing the shape of the lens for far and near vision. This structure contains muscles that contract or relax to adjust the tension in the suspensory ligaments, which in turn alters the shape of the lens. When the ciliary body contracts, the suspensory ligaments loosen, allowing the lens to become thicker and rounder for near vision. Conversely, when the ciliary body relaxes, the suspensory ligaments tighten, causing the lens to become flatter for far vision.

When a G protein becomes activated and causes an activation of enzymes, it triggers a series of cellular events. One of these events is the consumption of ATP, which provides the necessary energy for the enzymatic reactions. Additionally, the activation of enzymes by the G protein also leads to the formation of cAMP, a secondary messenger molecule that plays a crucial role in intracellular signaling. Therefore, the correct answer is that ATP is consumed and cAMP is formed during this process.

The pupillary muscle groups are controlled by the autonomic nervous system (ANS). Parasympathetic activation causes pupillary constriction, which means the pupils become smaller. On the other hand, sympathetic activation causes pupillary dilation, which means the pupils become larger.

The postganglionic fibers that innervate targets in the body wall or thoracic cavity originate on neurons within the sympathetic chain ganglia. These ganglia are located on either side of the spinal cord and are part of the sympathetic division of the autonomic nervous system. The sympathetic chain ganglia receive preganglionic fibers from the spinal cord via the white rami, and then the postganglionic fibers extend from these ganglia to innervate their target organs or tissues. Therefore, the sympathetic chain ganglia are responsible for transmitting sympathetic signals to the body wall and thoracic cavity.

A visceral motor neuron whose cell body is within the CNS is called a preganglionic neuron. Preganglionic neurons are responsible for transmitting signals from the central nervous system to the autonomic ganglia, where they synapse with postganglionic neurons. These postganglionic neurons then innervate the target organs and carry out the autonomic functions of the body.

Postganglionic sympathetic axons release the neurotransmitter acetylcholine at their effector junctions, as well as nitric oxide and norepinephrine. Acetylcholine is released at the synapses of the parasympathetic nervous system, but it also plays a role in the sympathetic system. Nitric oxide is a vasodilator that is released by sympathetic neurons to relax smooth muscle in blood vessels. Norepinephrine is the primary neurotransmitter released by sympathetic neurons, which activates adrenergic receptors to elicit a response in the target organ. Therefore, all of the above neurotransmitters are released by postganglionic sympathetic axons at their effector junctions.

The external ear consists of the pinna, ear canal, and tympanic membrane. The pinna is the visible part of the ear, while the ear canal leads to the tympanic membrane, also known as the eardrum. The tympanic membrane marks the end of the external ear and separates it from the middle ear. It vibrates in response to sound waves and transmits them to the middle ear. Therefore, the correct answer is the tympanic membrane.

The utricle and saccule are parts of the inner ear that convey information about head position with respect to gravity. They contain tiny hair cells that are sensitive to changes in head position and movement. When the head moves, the movement of the fluid in the utricle and saccule causes the hair cells to bend, which sends signals to the brain about the head's orientation in space. This information is important for maintaining balance and coordinating movements.

Parasympathetic stimulation refers to the activation of the parasympathetic nervous system, which is responsible for rest and digestion. When the parasympathetic nervous system is stimulated, it increases gastric motility, meaning it promotes the movement and contraction of the muscles in the stomach and intestines, aiding in digestion and the absorption of nutrients. This response helps to break down food and move it through the digestive tract efficiently.

The correct sequence of neural wiring in the retina starts with the rod cells, which transmit signals to bipolar cells. The bipolar cells then relay the signals to ganglion cells, which send the information to the brain via the optic nerve. From the optic nerve, the signals are sent to the thalamus, which acts as a relay station for sensory information before it reaches the visual cortex for processing.

Parathyroid hormone (PTH) is responsible for regulating calcium and phosphorus levels in the body. It acts to increase blood calcium levels by stimulating the release of calcium from bones, increasing calcium absorption in the intestines, and reducing calcium excretion in the kidneys. In contrast, calcitonin works to decrease blood calcium levels by inhibiting bone breakdown and increasing calcium excretion in the kidneys. Therefore, parathyroid hormone is the hormone that opposes the action of calcitonin.

The structure that overlies the organ of Corti is the tectorial membrane. The tectorial membrane is a gelatinous structure that extends over the hair cells of the organ of Corti in the inner ear. It plays a crucial role in the process of hearing by bending the hair cells when sound waves pass through the cochlea. This bending of the hair cells stimulates the auditory nerve, allowing the brain to perceive sound. The basilar membrane, stapedius, perilymph, and endolymph are all important components of the inner ear, but they do not directly overlay the organ of Corti.

A decrease in the autonomic tone of the smooth muscle in a blood vessel would result in an increase in vessel diameter. This is because the autonomic nervous system regulates the constriction and relaxation of smooth muscle in blood vessels. When the autonomic tone decreases, the smooth muscle relaxes, leading to vasodilation and an increase in vessel diameter. This, in turn, allows for an increase in blood flow through the vessel, as the larger diameter provides less resistance to the flow of blood. Therefore, both an increase in vessel diameter and an increase in blood flow through the vessel would occur.

Stimulation of α1 adrenergic receptors by norepinephrine results in the release of calcium ions from intracellular stores. This is because activation of α1 adrenergic receptors leads to the activation of phospholipase C, which in turn cleaves phosphatidylinositol 4,5-bisphosphate (PIP2) into inositol trisphosphate (IP3) and diacylglycerol (DAG). IP3 then binds to receptors on the endoplasmic reticulum, causing the release of calcium ions from intracellular stores. This increase in intracellular calcium ions can have various effects on cellular processes, such as muscle contraction or hormone secretion.

The zona glomerulosa of the adrenal cortex is responsible for producing mineralocorticoids. Mineralocorticoids are a class of steroid hormones that regulate electrolyte and water balance in the body. They primarily act on the kidneys, promoting the reabsorption of sodium and the excretion of potassium. This helps to maintain proper fluid balance and blood pressure. Androgens are produced in the zona reticularis, glucocorticoids in the zona fasciculata, and epinephrine and norepinephrine in the adrenal medulla.

The zona reticularis of the adrenal cortex is responsible for producing androgens. Androgens are a group of male sex hormones, such as testosterone, that play a role in the development of male reproductive organs and secondary sexual characteristics. These hormones are also present in females, albeit in smaller quantities, and contribute to various physiological functions. Therefore, the correct answer is androgens.

Olfactory pathways do not project first to the mamillary bodies and then to the thalamus. Instead, they reach the forebrain without first synapsing in the thalamus. The olfactory bulb is the site of the first synapse in the olfactory pathways. Information then flows to the olfactory cortex, hypothalamus, and limbic system. Olfactory pathways also exhibit a considerable amount of convergence, meaning that multiple olfactory receptor neurons can synapse onto a single mitral cell in the olfactory bulb.

Olfactory receptors are located in specialized olfactory cilia, which are tiny hair-like structures in the nose. These receptors are responsible for detecting odorants. When an odorant molecule binds to the receptors in the olfactory cilia, it triggers a series of biochemical reactions that generate electrical signals, which are then transmitted to the brain for interpretation. Therefore, for an olfactory receptor to detect an odorant, it must first bind to receptors in the olfactory cilia.

Muscarinic receptors are a type of receptor that are typically activated by the neurotransmitter acetylcholine. These receptors are found in various parts of the body, including smooth muscle, cardiac muscle, and certain glands. Activation of muscarinic receptors can lead to a variety of responses, including both excitatory and inhibitory effects depending on the specific tissue and receptor subtype involved. Norepinephrine, on the other hand, typically acts on adrenergic receptors and does not directly block muscarinic receptors.

The correct answer is that the statement "Preganglionic fibers are relatively short and postganglionic fibers are relatively long" is false. In the parasympathetic division of the autonomic nervous system, the preganglionic fibers are relatively long, while the postganglionic fibers are relatively short. This is the opposite of what is stated in the false statement.

The exhaustion phase of the general adaptation syndrome (GAS) is the third and final stage of the body's response to stress. During this phase, the body's resources become depleted, leading to a decrease in resistance to diseases and infections. This happens because the body's immune system is weakened due to prolonged stress. Therefore, the correct answer is decreased resistance to disease and infection.

The olfactory receptors send axons through the cribriform plate and synapse on neurons in the olfactory bulb. The olfactory bulb is responsible for processing and integrating the sensory information received from the olfactory receptors. From the olfactory bulb, the information is then transmitted to other areas of the brain, including the cerebral cortex, where it is further processed and interpreted. Therefore, the olfactory bulb is the correct answer as it is the initial site of processing for olfactory information.

Parathyroid hormone stimulates osteoclast activity, inhibits osteoblast activity, stimulates the formation and secretion of calcitriol at the kidneys, and enhances the reabsorption of calcium at the kidneys. However, it does not directly build up bone. Instead, it regulates calcium levels in the body by increasing the release of calcium from the bones when needed.

The ciliary muscle contracts to adjust the shape of the lens for close vision. When the ciliary muscle contracts, it causes the lens to become thicker and more rounded, allowing the eye to focus on nearby objects. This process is known as accommodation and is necessary for clear vision at close distances.

MSH, or melanocyte-stimulating hormone, is produced by the pars intermedia of the adenohypophysis during early childhood. It plays a role in the regulation of skin pigmentation and is responsible for stimulating melanocytes to produce melanin. This hormone is important for the development of skin color and pigmentation during early childhood.

The growth hormone is responsible for promoting bone growth, muscle growth, glucose sparing, and amino acid uptake by cells. However, it does not cause fat accumulation within adipocytes. Adipocytes are fat cells, and the growth hormone does not directly stimulate the accumulation of fat in these cells.

The basilar membrane is a structure in the inner ear that moves up and down in response to the movement of the stapes bone. This movement is essential for the process of hearing. When sound waves enter the ear and cause the tympanic membrane to vibrate, the vibrations are transmitted through the middle ear to the stapes. The stapes then moves back and forth, causing the basilar membrane to move up and down. This movement stimulates the hair cells on the basilar membrane, which convert the vibrations into electrical signals that are sent to the brain for interpretation.

The statement "Preganglionic axon terminals release acetylcholine" is true for both the parasympathetic and sympathetic nervous systems. In both systems, the preganglionic neurons release acetylcholine as their neurotransmitter. This acetylcholine then binds to nicotinic receptors on the postganglionic neurons, leading to the transmission of the nerve impulse to the target organ or tissue. This is a key characteristic of the autonomic nervous system, which is responsible for regulating involuntary bodily functions.

Epinephrine and Melatonin are hormones that are derived from amino acids. Epinephrine, also known as adrenaline, is derived from the amino acid tyrosine, while Melatonin is derived from the amino acid tryptophan. Therefore, they are considered amino acid derivatives.

Cells have the ability to respond to multiple hormones simultaneously. This is because different hormones can have different effects on various cellular processes and functions. The presence of multiple hormone receptors on the cell surface allows for the activation of different signaling pathways and the regulation of various cellular responses. Thus, cells can respond to several hormones at the same time, enabling them to integrate and coordinate multiple physiological signals for appropriate cellular responses.

Thyroid-stimulating hormone is not an amino acid derivative because it is a glycoprotein hormone. It is produced and released by the anterior pituitary gland and acts on the thyroid gland to stimulate the production and release of thyroid hormones. On the other hand, epinephrine, norepinephrine, and melatonin are all derived from amino acids. Epinephrine and norepinephrine are derived from the amino acid tyrosine, while melatonin is derived from the amino acid tryptophan.

The fibrous tunic of the eye consists of the sclera, limbus, and cornea, providing mechanical support and some protection for the eye. It also serves as the site where extrinsic eye muscles insert, allowing for eye movement and control. However, it does not produce aqueous humor. Aqueous humor is produced by the ciliary body, which is part of the vascular tunic of the eye.

When an individual experiences stress for an extended period of time, they enter the resistance phase of the general adaptation syndrome (GAS). During this phase, the body tries to adapt to the ongoing stress by stabilizing physiological functions and attempting to restore balance. The body's defenses are activated, and the individual may experience increased energy levels and improved resistance to stress. This phase is characterized by the body's continued efforts to cope with the stressor and maintain a state of equilibrium.

The "F" cells of the pancreatic islets produce pancreatic polypeptide. Pancreatic polypeptide is a hormone that is released by the pancreas in response to food intake. It plays a role in regulating digestion and metabolism. This hormone helps to inhibit the secretion of other pancreatic enzymes and reduces the rate at which food leaves the stomach, allowing for better digestion and absorption of nutrients. Additionally, pancreatic polypeptide has been found to have effects on appetite regulation and may play a role in controlling food intake.

The statement "Its postganglionic axons always use acetylcholine as the neurotransmitter." is true only for the parasympathetic nervous system. This means that in the parasympathetic nervous system, the neurotransmitter used by the postganglionic axons is always acetylcholine. In contrast, the sympathetic nervous system uses a combination of acetylcholine and norepinephrine as neurotransmitters. The somatic nervous system, on the other hand, primarily uses acetylcholine as the neurotransmitter at the neuromuscular junction.

The vitreous body is a gel-like substance that fills the posterior cavity of the eye, providing physical support to the retina and helping to stabilize the eye. It does not fill the anterior cavity, nor is it removed and recycled every few hours. Therefore, the correct answer is that it helps to stabilize the eye and give physical support to the retina.

The sympathetic division of the ANS is known as the thoracolumbar division. This division is responsible for the body's response to stress and is involved in the "fight or flight" response. It originates from the thoracic and lumbar regions of the spinal cord and innervates organs and tissues throughout the body. The sympathetic division prepares the body for action by increasing heart rate, dilating blood vessels, and activating the release of adrenaline.

The sensory receptors of the semicircular canals are located in the ampullae. The ampullae are enlarged regions at the base of each semicircular canal, where the sensory hair cells are located. These hair cells detect the movement of fluid within the canals, which helps in maintaining balance and detecting changes in head position and movement. The ampullae contain the cupulae, which are gelatinous structures that deflect in response to fluid movement, stimulating the hair cells and sending signals to the brain about the body's orientation in space.

Clusters of ganglionic sympathetic neurons that innervate organs in the abdominopelvic region are called collateral ganglia. Collateral ganglia are located outside the paravertebral chain and are situated close to the target organs they innervate. These ganglia receive preganglionic fibers from the sympathetic chain and provide postganglionic fibers to the organs in the abdominopelvic region.

The exocrine portion of the pancreas is responsible for producing digestive enzymes. These enzymes help in the breakdown of food in the small intestine and aid in the digestion and absorption of nutrients. Insulin is produced by the endocrine portion of the pancreas and is involved in regulating blood sugar levels. Parathyroid and somatotropin are hormones produced by other glands in the body, not the pancreas. Bile is produced by the liver and stored in the gallbladder, not the pancreas.

A sudden rise in room brightness would cause the pupillary constrictor muscles to contract. These muscles are responsible for reducing the size of the pupil, allowing less light to enter the eye. When there is a sudden increase in brightness, the pupillary constrictor muscles automatically contract in order to protect the delicate structures of the eye from excessive light. This contraction helps to regulate the amount of light entering the eye and prevents potential damage to the retina.

The celiac ganglion is not a parasympathetic ganglion. Parasympathetic ganglia are located close to or within the target organs and are responsible for transmitting parasympathetic signals. The ciliary ganglion, pterygopalatine ganglion, submandibular ganglion, and otic ganglion are all examples of parasympathetic ganglia that are associated with specific cranial nerves and control various functions in the head and neck region. However, the celiac ganglion is part of the sympathetic nervous system and is involved in the regulation of abdominal organs.

The sympathetic innervation of the urinary bladder is provided by the inferior mesenteric ganglion. This ganglion is responsible for transmitting signals from the sympathetic nervous system to the bladder, helping to regulate its function. The other ganglia mentioned in the options are not specifically involved in the sympathetic innervation of the bladder.

The statement "its ganglia are usually near or within the end organ" is true only for the parasympathetic nervous system. This is because the parasympathetic nervous system has ganglia located near or within the target organs, allowing for a more localized and specific control of the organ's function. In contrast, the sympathetic nervous system has ganglia located closer to the spinal cord, which allows for a more widespread and generalized response throughout the body. Therefore, the statement is not true for the sympathetic nervous system.

The organ of Corti is a structure located within the cochlea of the inner ear and is responsible for converting sound vibrations into electrical signals that can be interpreted by the brain. The basilar membrane is a key component of the organ of Corti, providing support and housing the sensory hair cells that detect sound waves. As sound waves travel through the cochlea, they cause the basilar membrane to vibrate, stimulating the hair cells and initiating the process of hearing. Therefore, the basilar membrane is the structure that supports the organ of Corti.

The movement of the endolymph in the semicircular canals is responsible for signaling rotational movements. The semicircular canals are fluid-filled structures in the inner ear that detect changes in head rotation. When the head moves, the endolymph inside the canals also moves, stimulating hair cells that send signals to the brain. This allows us to sense and perceive rotational movements, such as turning our head or spinning around. Therefore, the correct answer is that the movement of the endolymph in the semicircular canals signals rotational movements.

The frequency of a perceived sound depends on which part of the cochlear duct is stimulated. This is because the cochlear duct is responsible for converting sound waves into electrical signals that can be interpreted by the brain. Different parts of the cochlear duct are sensitive to different frequencies of sound, so when a specific part is stimulated, it sends signals to the brain that correspond to that frequency. Therefore, the frequency of the perceived sound is determined by which part of the cochlear duct is stimulated.

The taste buds, which are responsible for detecting different flavors, are monitored by cranial nerves VII, IX, and X. Cranial nerve VII, also known as the facial nerve, innervates the taste buds on the anterior two-thirds of the tongue. Cranial nerve IX, the glossopharyngeal nerve, innervates the taste buds on the posterior one-third of the tongue. Cranial nerve X, the vagus nerve, innervates the taste buds in the epiglottis and the back of the throat. Therefore, these three cranial nerves collectively monitor the taste buds throughout the tongue and throat.

Steroid hormones are not produced by the adrenal medulla. The adrenal medulla produces catecholamines such as adrenaline and noradrenaline. Steroid hormones are produced by the adrenal cortex, which is a different part of the adrenal gland. Steroid hormones are derived from cholesterol, produced by reproductive glands, and bind to receptors within the cell.

The correct answer is "contain four types of endocrine cells." The pancreatic islets, also known as islets of Langerhans, are clusters of cells in the pancreas that contain four types of endocrine cells: alpha cells, beta cells, delta cells, and PP cells. These cells are responsible for producing and releasing hormones such as insulin, glucagon, somatostatin, and pancreatic polypeptide, which play crucial roles in regulating blood sugar levels and other metabolic processes in the body. The other options mentioned in the question, such as making up almost half of the pancreas and producing digestive enzymes, are not accurate descriptions of the pancreatic islets.