anatomy and Physiology chapter 12,13,14,15

What would happen if Na+ gates did not close after the membrane potential reached 0mV?

-During the Repolarization phase of the Action Potential steps, voltage gated Na+ channels are to close when 0mV is reached. This then allows voltage gated K+ channels to open. K+ then flows out of the neuron so the charge decreases. This overall restores resting membrane potential, which would not occur if the Na+ gates did not close after the membrane potential reached 0mV.

What would happen if reciprocal innervation did not occur during a patellar reflex?

-The reciprocal innervation happens to insure that the contraction of the stretched muscle does relieve the stretch, antagonistic muscles are inhibited to prevent opposition to the contraction. With out it the contraction of the stretched muscle does not relieve the stretch and the antagonistic muscles are not kept from opposing the contraction.

What would happen if an individual's CNS myelin sheaths degenerated and were replaced with scar tissue?

A If this were to occur, an individual would develop Multiple Sclerosis which is caused by a progressive degeneration of oligodendrocytes and myelin sheaths in the CNS. When degeneration of the myelin sheaths in the CNS begins to degenerate and is replaced with scar tissue, this tissue "healing" is known as Fibrosis. It causes weakness in the muscles, abnormal sensations and double vision. MS is an autoimmune disease that affects 2 million people worldwide with females being more susceptible to autoimmune disorders due to childbearing. MS appears between the ages of 20 to 40 and has genetic and viral contributions as well.

How could you tell if you were observing a region of plasma membrane that was experiencing a graded or an action potential?

A graded potential is short distance communication. It responds to stimulus and is along dendrites and somas. Action potentials are long distance communication and are along axons. They stimulate release of neurotransmitters from synaptic end bulb.

What would happen if a lesion occurred in the right parietal lobe?

A lesions occurs when there is local brain injuries caused by trauma, cancer, stroke, are some examples. The somatosensory area; Parietal lobe determines the characteristics of objects through touch as well as being able to recognition of various items. A right parietal lobe lesion would inhibit the touch receptors on the left of the individual.The lesion would not inhibit the receptors... they detect the stimuli in the skin. It would prevent the receipt, thus perception and awareness of the information for example contralaterally neglect half of their face due to the damaged portions of the brain.

what is the physiological significance of graded potentials being graded and decremental?

A: Being graded (size of potential is relative to size of stimulus) and decremental (within the cell, the charge change decreases the further you are from the stimulus) allow for a cell to only respond to stimuli that are large enough to warrant their attention.

What is the physiologic significance of myelin?

A: Myelin is the covering that wraps around the plasma membrane of the of the axon. It is made of lipid and protein. It increases the speed of electrical signals traveling through the neuron. In the central nervous system myelin is made of oligodendrocyte cells and in the peripheral nervous system it is made from Schwann cells. If the myelin sheath degrades it can lead to multiple sclerosis.

__ influence of blocking voltage gated Ca2+ channels on the synaptic knob on the ability of the neuron to produce ACh

A: N because the Ca2+ triggers the exocytosis of neurotransmitters such as ACh, ACh is produced in the soma, not the production of ACh.

What is the physiologic significance of the ANS?

A: The ANS controls viscera, which is glands, smooth muscle and cardiac muscle, without our being aware of it. Although visceral effectors do not depend on the ANS to function, it's sympathetic division prepares the body for action by doing things like speeding the heart rate and slowing digestion. It's parasympathetic division calms the body by doing things like increasing digestion and slowing heart rate

What is the physiologic significance of the anterior nucleus of the thalamus?

A: The thalamus is one of the three parts of the diencephalon which is the central core of brain tissue superior to the midbrain encased by the cerebrum. The thalamus is an oval mass of gray matter that functions as the gateway to the cerebral cortex and is surrounded by lateral ventricles. The anterior nucleus of the thalamus is responsible for emotions and memories.

How could you tell if a membrane was in an absolute or relative refractory period?

Absolute: during ongoing AP. No stimulus can trigger another AP at this time. Relative: During hyperpolarization. Membrane is less than -70. A large stimulus could trigger another AP.

7. How could you tell by looking at the synaptic knob, if a neuron was able to conduct axonal transport?

Axonal transport is transport of molecules between soma and synaptic end bulb/knob. Many proteins are needed for axonal transport. In the synaptic knob, you would need to see voltage gated Calcium channels, Acetylcholinesterase enzymes, and Acetylcholine neurotransmitters if a neuron able to conduct axonal transport.

How could you tell if a neuron belonged to the gracile fasciculus tract?

Both gracile fasciculus and cuneate fasciculus relay sensory information about light pressure, tough, vibration, and proprioception. But gracile fasciculus signals from the legs, while cuneate fasciculus signals from the arms

How could you tell if an individual was specialized to use their categorical or representational cerebral hemisphere?

Cerebral hemispheres are not functional mirror images. Neither is dominant, but each is specialized Categorical hemisphere (Left hemisphere): Specialized for spoken and written language, sequential & analytical reasoning (math & science ability). Representational hemisphere (Right hemisphere): Perceives information more holistically. Perception of spatial relationships and pattern, imagination and insight (music and artistic skill)

Influence of blocking the central nervous system on the ability to respond to a particular stimulus.

D, the CNS contains the brain and spinal cord which serve an integrative function in decision making for response to stimuli.

Influence of removing the arachnoid villi on the ability of waste to be removed from the CSF?

DECREASE. Arachnoid villi are tree-shaped connections between the CSF-filled subarachnoid space and the dural venous blood sinuses that allow for the transfer of waste from cerebrospinal fluid to blood. Without arachnoid villi, the ability of waste to be removed from CSF would decrease.

___Influencing of removing the frontal lobe of the cerebrum on the ability to perceive light?

Decrease, because, although you can technically live without a frontal lobe, The frontal lobe directs a person's personality, judgement, foresight, reasoning, mood, planning. It really results in not very socially acceptable behaviors. For example Phineas Gage, his frontal lobe was damagedPhineas gage could still perceive light becuase this is accomplished by the occipital lobe.

Influence of blocking all second order neurons on the perception of an itch.

Decrease, somatic sensory pathways are general pathways for itch, which consists of the first order neuron relaying information from the receptor to the spinal cord, second order neurons relaying this information from the spinal cord to the thalamus (via decussation) and third order neurons relaying information from the thalamus to the postcentral gyrus and the primary somatosensory cortex where perception of the itch would take place. Blocking second order neurons would prevent this relaying of information and conscious awareness could not take place.

Influence of creating lesions on the superior colliculi on the ability to watch a basketball game.

Decrease, the superior colliculi tracks moving objects as well as stationary objects. The head reflexes following these objects. If a lesion were formed on the superior colliculi then it would not be able to track objects efficiently. If an individual was not able to track moving or stationary objects watching a basketball game would be very difficult.

Influence of blocking all efferent neurons on the probability of completing a reflex.

Decrease. For a reflex to occur, stimulation causes a sensory receptor to activate afferent neurons, which send the sensory info to an interneuron. The interneuron sends an efferent impulse to activate motor neuron and activate the effector (cause the reflex). Without efferent neurons, the signal to respond to a stimulus with a reflex would not reach the effector (skeletal muscle) so a reflex would not occur.

Influence of preventing stimulus transduction on the ability to sense a change in the environment?

Decrease. Stimulus transduction is when sensory receptors convert stimulus into a graded generator potential. The sensory receptor detects a change in the environment but without the ability to transmit that signal graded potential there would be no signal sent. Thus there would be no response because the stimulus would never be consciously detected. Action potentials would thus not be generated.

Influence of creating a lesion in the medulla oblongata on the ability to adjust blood vessel diameter.

Decrease; The Medulla Oblongata contain nuclei that regulate involuntary motor mechanisms such as the cardiovascular center, which adjusts rate and force of heart contractions and blood vessel diameter. If their was damage to the medulla oblongata, these nuclei could be damaged and they would not provide the function of regulating the diameter of the blood vessel.

How could you tell if an organ's dual innervation was antagonistic or cooperative?

Dual innervation refers to an organ receiving signals from both the parasympathetic and sympathetic divisions of the ANS. When the effects of these two divisions on an organ are opposite, the innervation is antagonistic. The effects can occur through dual innervation of the same effector cells, or through dual innervation of different effector cells. An example of dual innervation of the same effector cells would be the heart rate decreasing (parasympathetic) or increasing (sympathetic). An example of dual innervation of different effector cells would be the innervation of the muscles involved in the opposite effects of pupil dilation (sympathetic) and constriction (parasympathetic). Cooperative dual innervation occurs when the effects of the parasympathetic and sympathetic divisions act on different effector cells to produce a unified overall effect. An example would be salivation. The parasympathetic division increases salivary serous cell secretion, and the sympathetic division increases salivary mucous cell secretion.

What would happen if EPSP's underwent summation to a threshold level in the trigger zone?

EPSPs are excitatory graded potential. If an excitatory graded potential reached threshold, an action potential would be generated.

How could you tell if a post-synaptic potential was an EPSP or an IPSP?

Excitatory Post Synaptic Potential (ESPS) is the post synaptic potential where the charge in the cell increases from ion channels opening up and Na+ or Ca++ entering the cell changing the charge in the cell to a positive one. Inhibitory Post Synaptic Potential (ISPS) is a post synaptic potential where the charge in the cell is decreased, ions with a negative charge enter the cell creating this decrease.

What is the physiologic significance of GABA triggering Cl- gates in a post-synaptic neuron?

GABA from presynaptic neuron opens Cl- channel on the postsynaptic neuron. Cl- flows into the channel and the charge in the cell decreases. This leads to hyperpolarization which decreases the chances that the postsynaptic cell will have an action potential.

How could you tell if spinal cord tissue was gray or white matter?

Gray Matter Darker in color and contains somas of neurons, very little myelin, centrally located. White Matter is Lighter in color contains axons of neurons, contains myelin and is mostly composed of phospholipids is found on the outside.

How could you tell if an individual's habenular nuclei were functional?

Habenular nuclei are part of the epithalamus or diencephalon. You could tell if their habenular nuclei was functional if they had a sense of emotion when they smell something.

___Influence of a graded potential reaching threshold level at the axon hillock on the likelihood of generation of an action potential.

I, If a graded potential is large enough it will automatically generate an action potential. Dramatic changes in membrane potential lead to a communication down the axon, which will produce action potential in the "trigger zone" (an area of high density of voltage-gated channels) on the axon hillock. Each action potential triggers a subsequent action potential further down the axon.

How could you tell if a neuron had the property of secretion?

If a neuron had the property of secretion, the neuron would release acetylcholine. This secretion would takes place after the neuron goes through the two prior properties, including excitability and conductivity

How could you tell if a synapse was electrical or chemical?

If a synapse was electrical it would have continuation of action potentials using gap junctions it would also be faster and synchronized, An example of this would be cardiac muscle cells. Then is synapse was chemical there would be re-initiation of action potentials using secreted chemicals called neurotransmitters. Neuromuscular junction is an example of this.

What would happen to an EEG if the individual being monitored experienced extreme emotional stress?

If the individual being monitored experienced extreme emotional stress the EEG (Electroencephalography) would show brain waves similar to Theta Waves indicating that they are experiencing emotional stress.

How could you tell if the median and lateral apertures were clogged?

If the median and lateral apertures were clogged then The cerebrospinal fluid could not be drained. The apertures connect the fourth ventricle to the subarachnoid space.

What would happen if the medulla oblongata did not function correctly?

If the medulla oblongata didn't function properly you would have no sense of touch, pressure, pain or tempurature. The medulla oblongata contains gustatory, cochlear, and vestibular nuclei that participate in special sense. The senses would not be present if the medulla oblongata didn't function properly.

How could you tell if you were observing PNS neurons that originated from the lateral or anterior horns of the spinal cord gray matter?

If the neuron you are observing was an autonomic motor neuron, it would have originated from the lateral horn. If the neuron you are observing was a somatic motor neuron, it would have originated from the anterior horn.

What would happen if nodes of Ranvier were covered with myelin?

If the nodes of Ranvier were covered then the voltaged gated Na+ channels would also be covered. With these channels covered sodium wouldn't be able to continue depolarizing the axolemma and continue down to the distal end of the axon to the synapse. The original action potential would be lost.

Influence of removing ependymal cells from the choroid plexus on the likelihood of brain death.

Increase. All ventricles in the brain contain choroid plexuses, which have networks of ependymal cells in them. CSF also suspends the brain in the skull, and cushion from outside blows, and without it, the brain would take all the abuse directly, which can also lead to brain death.

Influence of transection of the lumbar spinal cord on the chances of becoming quadriplegic.

N, As a spinal injury only impacts the areas below it, transection of the lumbar spinal cord (L1) would not cause quadriplegia, but would result in paraplegia. Quadriplegia would result from injury to specific cervical vertebrae (C6 or C4).

Influence of removing efferent neurons from a visceral reflex arc on the ability of the brain to detect internal stimuli.

N, No change. Introceptors detect internal stimuli and the efferent neurons carry the motor signals to effectors.

Influence of hyperpolarizing all somatic cutaneous sensory receptors on the perception of pain in the arm during a heart attack.

N, because the somatic cutaneous sensory receptors are not actually being fired. The brain is assuming this. This is called referred pain. The brain assumes that visceral pain is coming from the skin because it it more likely that there is damage to the skin coupled with mixed up neurons than there is damage to the internal organs.

Influence of removing motor neurons on the ability of an individual to sense external stimuli.

N, motor neurons carry efferent signals to effectors; sensory, afferent neurons carry sensory information from receptors to CNS.

___ influence of removing ganglia from the somatic motor pathway on effector function.

NC, ganglia are swollen parts of nerves where somas are concentrated. They are found in the posterior root (somatic sensory pathway) and the chain/prevertebral/terminal ganglia are in the autonomic motor pathways. There are no ganglia on the somatic motor pathways, all somatic motor somas are in the CNS.

Infulence of blocking all muscarinic receptors on the ability of NE to cause an action potential.

NC. NE binds to alpha and beta receptors. ACh binds to muscarinic receptors.

Influence of blocking all sympathetic sympathetic nerve routes on the ability of lumbar preganglionic neurons to influence cardiac function?

NO CHANGE. Lumbar preganglionic neurons (L1-L3) innervate the inferior mesenteric ganglion via the lumbar splanchic nerve. This influences the function of the urinary bladder, external genitals, uterus, rectum, and descending colon. Preganglionic neurons are only between T1 and L3, meaning the neurons of the cardiac plexus (T1-T4) are the only preganglionic neurons that influence cardiac function. Therefore, blocking all sympathetic sympathetic nerve routes would produce no change on the ability of lumbar preganglionic neurons to influence cardiac function.

_____ Influence of selectively removing all posterior rami on the ability to feel a tummy tickle.

NO CHANGE; The posterior ramus carries 2-way traffic of neurons to and from posterior muscle and skin. To lose the ability feel a tummy tickle the anterior ramus would be affected because it carries 2-way traffic of neurons to and from limbs, anterior muscle, and skin. The anterior muscle is where one would feel a tummy tickle.

Influence of inhibiting the postcentral gyrus on motor control.

NO CHANGE; the postcentral gyrus is located in the primary somatosensory area of the cerebrum, where the ascending tracts end and where touch sensory information is received. The precentral gyrus is located in the primary motor area of the cerebrum and the neurons that leave the precentral gyrus are the upper motor neurons of the descending tracts.

What is the physiologic significance of a resting membrane potential?

Neural communication relies on the production of electrical potentials and currents. Resting membrane potential is -70mV with a negative charge on the inside of the membrane, meaning the membrane is at rest, but has potential to create a current. The analogy we learned in class was that this is like the water behind a dam, just waiting to be activated in a sense.

What is the physiologic significance of neurotransmitters?

Neurotransmitters are chemicals released from synaptic bulbs/ends of neurons into the synaptic cleft between the neuron and receiving cell. Neurotransmitters either excite or inhibit another neuron, muscle fiber, or gland cell. The most common neurotransmitter is acetylcholine(ACh), which is released in the neuromuscular junction, functioning in communication between our nervous system and muscular system. Neurotransmitters, such as acetylcholine, initiate graded potentials, which initiate action potentials, in a cycle that ultimately results in the effector organ (the muscles, in the case of acetylcholine) performing the required function.

What is the physiologic significance of nicotinic receptors?

Nicotinic receptors are in all Neuromuscular Junctions, NMJ, and are excitatory when they bind to acetylcholine, ACh. Nicotine mimics ACh in these receptors but that was not the intention, they are only suppose to bind to ACh.

Influence of degeneration of Cholinergic Neurons on the progression of an Individuals Parkinson's disease.

No Change, Influence of degeneration of Cholinergic Neurons would not influence the progression of an individuals Parkinson's disease. The underlining cause of Parkinson's disease is the degeneration of dopamine releasing neurons. Dopamine prevents excessive activity in the motor centers of the brain and involuntary muscle contractions. The degeneration of Cholinergic Neurons would increase a patients progression of Alzheimer's Disease/Dementia since Cholinergic Neurons secrete Acetylcholine.

___Influence of blocking slow axonal transport on the ability of a neuron to move proteins towards the soma.

No change. Slow axonal transport is anterograde transport; retrograde transport would move the axon towards the soma. This type of axonal transport is used to move large compounds.

__Influence of destroying Schwann cells on the level of myelination in the CNS.

None, for CNS myelination oligodendrocytes are needed, while Schwann cells are needed for PNS myelination.

How could you tell if you were observing the epineurium or endoneurium?

One could tell that they were observing the epineurium by noting that it is the first of the 3 C.T. Layers. It is the outermost layer that is continuous with the dura matter. An individual could tell that they are observing the endonuerium by noting that it is the last of the 3 C.T. Layers. It is the inner layer within the

What is the physiologic significance of pre-synaptic inhibition?

Presynaptic inhibition is the reduction of transmitter released from an excitatory presynaptic terminal by axoaxonic inhibitory synapse. This process plays a crucial role in normal function of the contraction cycle in a muscle, without presynaptic inhibition one would lose ability to contract their muscles causing paralysis.

What is the physiologic significance of REM sleep?

REM (Rapid eye movement) sleep occurs several times during the sleep period after a prolonged stage 4. Sleep paralysis also occurs during this time so one does not act out their dreams. The significance of REM sleep is unknown, it could be that it is important for brain maturation. Also without sleep you will die!

Influence of having a lesion in the frontal lobe on the ability to recognize objects?

Recognition of objects is coordinated by the temporal and occipital lobe. Not the frontal lobe.

How could you tell if the parasympathetic was dominant, by looking at the sweat glands?

Sweat glands cannot be seen by the naked eye, only the product of the sweat glands...actual secretion sweat. If the parasympathetic was dominant, there would be no change/no sweat production. If it were sympathetic, sweating would be more prominent in response to stress, danger and/or "fight or flight" situations. essentially, you could not tell. The sweat glands do not have dual innervation and are only innervated by the sympathetic division

How could you tell the difference between a sympathetic chain ganglion and a collateral ganglion?

Sympathetic chain ganglia is adjacent to both sides of the vertebral column from the base of the skull to the coccyx, and innervates organs that are above the diaphragm. Collateral Ganglia lie anterior to the vertebral column and innervate the organs that are below the diaphragm.

What would happen if an individual consumed sympathomimetics?

Sympathomimetics activate an individuals sympathetic signaling by stimulating receptors or increasing NE. For example, Chlor-Trieton/Dimetapp stimulates alpha 1 receptors which dilates bronchioles and constrict nasal blood vessels.

What is the physiological significance of the blood brain barrier(BBB)?

The BBB limits water soluble molecules and organisms from passing. This stops bacteria, hormones enzymes and other things from freely passing and potentially damaging the brain. It is still permeable to lipid soluble materials like O2 and CO2 to all for easy cellular respiration though.

what would happen if an individual had a lesion in their Broca area?

The Broca area is located and associated with the motor area of the frontal lobes. Helps direct speaking by using the muscles of the larynx, tongue, cheeks and lips. This would inhibit an individual's ability to speak normally.

What would happen if the interventricular foraminifera was clogged?

The CSF would not flow FROM the lateral ventricles to the 3rd ventricle. Which would cause it to continue to form within that ventricle, the blocked ventricle would swell with a fluid called hydrocephalus. When they are blocked they can give arise to a disease.

What would happen to heart rate if the sympathetic division was dominant?

The autonomic tone that monitors heart rate is the parasympathetic tone which maintains our heart rate at about seventy beats per minute. If the sympathetic division was dominant then the heart rate would increase to about a hundred beats per minute.

. What is the physiologic significance of the corticospinal tract?

The corticospinal tracts are descending tracts that relay motor commands from the cerebral cortex to the anterior gray horns of the spinal cord for precise, finely coordinated limb moments.

What is the physiologic significance of a dendrite?

The dendrites are the information receiving processes of the neuron and are receptor proteins for binding to external chemical messages. The dendrites are shorter and more numbers than the axon.

How could you tell, without invasive techniques, the concentration of tactile receptors in a particular region of the epidermis?

The distance the person feels one point instead of two, this technique is called the two point discrimination test. The closer the distance, there is a higher concentration of receptors. You could "look" at the free nerve ending, which senses pain, itch, tickle, cold and warmth. As well as Type 1 cutaneous mechanoreceptor (tactile disc) senses fine touch and pressure.

What is the physiological significance of the enteric nervous system?

The enteric nervous system is the nervous system of the digestive track. It coordinates the activities of organs like the stomach and intestines independent of the CNS. The ANS can regulate the level of activity of the enteric nervous system.

What is the physiological significance of the hippocampus?

The hippocampus is one of three brain regions responsible for memory direction. This region organizes sensory and cognitive information into a new memory. Damage of this area of the brain would cause anterograde amnesia.

What is the physiologic significance of the hypothalamus to the ANS?

The hypothalamus is the major visceral motor control center in the ANS. It contains nuclei for primitive functions like hunger and thirst.

What is the physiologic significance of central pattern generators?

The physiologic significance of the central pattern generator is locomotion, the coordinating the activity of simple repetitive muscles groups in the spinal cord, an example of this is walking.

What is the physiologic significance of the cerebellum?

The physiologic significance of the cerebellum is that it monitors muscle contractions and aids in motor coordination.This allows our movement to look naturally smooth and controlled. It also contains timekeeping centers. This allows us to be conscious of time and having an "idea" of how much time has passed.

What is the physiological significance of a muscle spindle?

The physiological significance of a muscle spindle is that it is the proprioceptor in the perimysium that monitors the length of a muscle. It also contains intrafusal fibers that are surrounded by sensory nerves that relay info about sudden or prolonged stretching.

What is the physiologic significance of bradykinin?

The physiological significance of bradykinin is to prohibit inflammation. It is a peptide that causes blood vessels to dilate thus allowing blood pressure to fall. It is a chemical that helps to stimulate the pain neurons.

What is the physiologic significance of association areas?

The physiological significance of the association areas is to help our brain with memory, recognition, emotion, reasoning, judgment and intelligence. They Make decisions about sensory information. These areas include the somatosensory area, the prefrontal cortex, the orbitofrontal cortex, the visual association area, and the auditory association area.

What is the physiologic significance of the limbic system?

The physiological significance of the limbic system is that the limbic system provides storing of emotions and memory arousal along with behavior. For example a first kiss.

How could you tell the difference between the posterior and anterior roots of the proximal part of a spinal nerve?

The posterior root carries sensory input to the spinal cord while the anterior root carries motor output of the spinal cord. The posterior root contains posterior root ganglion while the anterior root does not.

What is the physiologic significance of the preganglionic neurons?

The preganglionic neurons only synapse int he terminal ganglia in the parasympathetic routes. The preganglionic neurons convey visceral motor signals from the CNS to ganglia where they synapse with postganglionic neurons that continue to effector organs. This is important for the function of the autonomic nervous system.

What is the physiologic significance of refractory periods?

The refractory period is the period of resistance to stimulation. Relative refractory periods occur during hyperpolarization, in which the threshold to achieve a new action potential is further than in membrane resting (>-70mV). This hyperpolarization resting period prevents sequential action potentials from traveling up the axon to the soma.

What is the physiologic significance of the reticular formation?

The reticular formation is a broad region where white matter and gray matter form a network throughout the brainstem(the midbrain, pons, and medulla oblongata). The neurons located in this region have sensory and motor functions. The ascending (sensory) portion is the reticular activating system(RAS), which consists of sensory axons that project to the cerebral cortex. The reticular formation is important in initiating consciousness, arousal, attention, and sleep, as well as preventing sensory overload

What would happen if the somatic motor division did not function?

The somatic motor division is part of the PNS and helps relay information from the CNS to the effector organs. Specifically the somatic motor division effects the skeletal muscles. It relays information from the CNS to the skeletal muscles. Without the somatic motor division, essentially you wouldn't be able to voluntarily move your skeletal muscles .

What would happen if the sympathetic division of the ANS was destroyed?

The sympathetic division prepares body for physical activity such as increase heart rate, decrease digestion, etc. If the sympathetic division was destroyed, the brain of an individual would not be able to send messages to other organs to perform an action.

What would happen if all unipolar somatic sensory neurons were replaced with multipolar neurons?

The unipolar neurons have the cell body set to the side in a more protected area (posterior root ganglion). This is because the soma is fragile and can not heal if it is damaged. If they were changed to multipolar neurons they would lose this extra protection. They would be prone to damage and neuron death and progressive loss of somatic sensation. So if they were now multipolar, the somas would be out with the dendrites near the potentially damaging stimuli.

Influence of blocking the projection tracts of the cerebral white matter on the ability to send a signal between cerebral hemispheres. NC.

The white matter projection tracts are groups of axons that connect the cerebrum, brainstem, and spinal cord. The corpus callosum is the connection point for signals between the two hemispheres. The blocking of the projection tracts would have no impact on the signal between hemisphere. It would however decrease signals between the cerebrum, brainstem and spinal cord. The commissural tracks travel through the corpus callosum to link the hemispheres.

What would happen if an individual did not have tendon organ receptors?

These receptors are proprioceptors that detect stretch of tendons due to excessive muscle contractions. Without them muscles could cause tendons to tear.

What is the physiological significance of the ANS having multiple neurotransmitters and receptors for each neurotransmitter?

We need two neurotransmitters to convey information to the same organs/cells from two different divisions. We need at least two receptor types for each neurotransmitter because within a division we have both excitatory and inhibitory responses.

How could you tell if an organ had dual innervation?

You can tell if an organ has dual innervation if an organ is regulated by both the sympathetic and parasympathetic divisions. Neither universally excites or calms. The effects of a organ will depend on neurotransmitters released by neurons. Sympathetic prepares the body for a flight or flight response whereas parasympathetic division calms body functions and assists with bodily functions. The heart, stomach, and small intestine would be examples of dual innervation organs.

How could you tell if you were observing a component of the CNS or PNS?

You would be able to tell if you were observing a component of the CNS or PNS Central because one system regulates and observes the internal environment and the other monitors the external environment. The Central Nervous System (CNS) are organs covered by bone, the CNS regulates the electrical signals of the brain and spinal cord and the Peripheral Nervous System (PNS) are organs not necessarily protected by bone, such as Nerves Bundle, Ganglia Enteric plexuses, sensory receptors neurons that keep an eye on the internal & external environments.