The Nervous System Study Resources

1. What kind of re- ionotropic ligand gated ion channels ceptors are nicotinic receptors? 2. where are nicotinic receptors found? Nicotinic receptors are found in both the central nervous system (CNS) and the peripheral nervous system (PNS). In the CNS, they are located on neurons, while in the PNS, they are present at neuromuscular junctions and autonomic ganglia. 3. What is the effect of activation of nicotinic receptors in the different cells/organs where they are found? Nicotinic Receptors: Effect: Muscle contraction at neuromuscular junctions, stimulation of postganglionic neurons in autonomic ganglia. Location: Found in neuromuscular junctions and autonomic ganglia. Muscarinic Receptors: Effect: Modulation of heart rate, smooth muscle contraction, glandular secretion, cognitive functions, and motor control. Location: Found in the heart, smooth muscle, glands, and throughout the central nervous system. 4. Where are mus- Muscarinic receptors are primarily found in the central carinic receptors and peripheral nervous systems, as well as in various found? non-neuronal tissues such as smooth muscle, cardiac muscle, and glandular tissue. 5. Do epinephrine Yes, both epinephrine (adrenaline) and norepinephrine and norepineph- (noradrenaline) bind to adrenergic receptors. rine also bind to adrenergic receptors? 6. Are there more than one type of adrenergic receptors? If so, what is the dif- Yes, adrenergic receptors are classified into two main types: alpha-adrenergic receptors (±adrenoceptors) and beta-adrenergic receptors (²-adrenoceptors). They differ in their structure, distribution, and downstream signaling pathways. 1/8 ference between them? 7. Effects of adren- Heart: Both alpha and beta adrenergic receptors are preergic receptors sent. on the heart? Alpha-1 adrenergic receptors: Contraction of cardiac muscle, leading to increased heart rate and contractility. Beta-1 adrenergic receptors: Increased heart rate, contractility, and conduction velocity. Beta-2 adrenergic receptors: Vasodilation of coronary arteries. 8. Effects of adren- Bronchiolar smooth muscle: Beta-2 adrenergic receptors ergic receptors predominant. Activation leads to the relaxation of smooth on the lungs? muscle, resulting in bronchodilation. 9. Effects of adren- Hepatocytes: Primarily beta-adrenergic receptors.Activaergic receptors tion leads to glycogenolysis and gluconeogenesis, inon the liver? creasing blood glucose levels. 10. Main function of the Central Nervous System (CNS): The main function of the CNS is to process and integrate sensory information received from the body and external environment, initiate appropriate motor responses, and regulate higher cognitive functions such as memory, learning, and emotion. 11. Main function of the Peripheral Nervous System (PNS): The main function of the PNS is to transmit sensory information from the body to the CNS (afferent division) and transmit motor commands from the CNS to muscles and glands (efferent division), thus facilitating communication between the CNS and the rest of the body. 12. What is the function of the cell body of the neurons? The cell body (or soma) of neurons is responsible for integrating incoming signals from dendrites and initiating action potentials if the signal is strong enough. It contains various organelles, including the nucleus, endoplasmic reticulum, Golgi apparatus, mitochondria, and ribosomes. These organelles play roles in protein synthesis, energy production, and overall cellular function. The term "soma" is often used to refer to the cell body of individual neu2/8 rons, while "ganglion" or "ganglia" refers to a collection of cell bodies (nuclei) in the peripheral nervous system. They serve similar functions but at different organizational levels. 13. What is the role of the axon? Do all neurons have an axon? Can a neuron have more than one axon? Can an axon have branches called "axon collaterals"? The axon is responsible for transmitting electrical impulses (action potentials) away from the cell body toward other neurons, muscles, or glands. Not all neurons have an axon; some neurons are anaxonic and have no discernible axon. Most neurons have a single axon, but some neurons, called multipolar neurons, have multiple dendrites and a single axon. Yes, axons can have branches called axon collaterals, which allow for communication with multiple target cells. 14. How is the synapse switched off? Reuptake: Neurotransmitters are taken back up into the presynaptic neuron via reuptake transporters, reducing their concentration in the synaptic cleft and terminating their action. Enzymatic Degradation: Some neurotransmitters are broken down by enzymes in the synaptic cleft, such as acetylcholine by acetylcholinesterase, halting their effects. Diffusion: Neurotransmitters can diffuse away from the synaptic cleft, decreasing their concentration at postsynaptic receptors and ending their action. Autoreceptors: Presynaptic neurons have autoreceptors sensitive to the neurotransmitter they release. Activation of these receptors triggers negative feedback, reducing further neurotransmitter release. Postsynaptic Receptor Desensitization: Prolonged activation of postsynaptic receptors leads to desensitization, reducing their responsiveness to neurotransmitters and inhibiting synaptic transmission. 3/8 15. How do solutes move through a membrane; down electrochemical gradient or against electrochemical gradient? Solutes move across membranes either down their electrochemical gradient (from high to low concentration) or against it (from low to high concentration), depending on specific transport mechanisms. 16. The plasma The plasma membrane separates the intracellular envimembrane pro- ronment (inside the cell) from the extracellular environvides a barrier ment (outside the cell). to separate two different environments in the cell, which ones? 17. What is the difference between a symport and antiport transport system? In a symport system, two or more molecules are transported across the membrane in the same direction. In contrast, in an antiport system, two or more molecules are transported across the membrane in opposite directions. 18. What is the difference between primary active transport and secondary active transport? In primary active transport, ATP hydrolysis provides energy to transport molecules across the membrane (e.g., sodium-potassium pump). Secondary active transport uses the electrochemical gradient established by primary active transport to move molecules against their concentration gradient (e.g., sodium-glucose cotransporter). 19. Definition of E The equilibrium potential for an ion is the membrane po(equilibrium po- tential at which the electrical and concentration gradients tential for an ion): for that ion are balanced, resulting in no net movement of the ion across the membrane. 20. Equation that cal- Nernst equation culates the equilibrium potential for an ion: 4/8 21. Equation that cal- Goldman-Hodgkin-Katz equation culates the Membrane Potential (Vm): 22. Resting memNegative brane potential of a neuron, positive or negative? 23. Concentration of Outside the cell Na+ (sodium) higher, outside the cell or inside the cell? 24. Concentration of Inside the cell K+ (potassium) higher, outside the cell or inside the cell? 25. Why does Lidocaine work as a local anaesthetic? What ion channels does it block? Does it block or enhance action potential in the nerves? Lidocaine works as a local anesthetic by blocking voltage-gated sodium channels in nerve cell membranes, thereby preventing the generation and propagation of action potentials. It blocks action potentials in nerves by inhibiting the influx of sodium ions, thus preventing depolarization of the cell membrane and subsequent action potential generation. 26. What are the 2 Support and nourish neurons. main functions of Insulate and protect neurons. the glia cells in the nervous system? 27. 5/8 What are the Astrocytes, oligodendrocytes, microglia, and ependymal names of the 4 cells. types of glia cells that are in the central nervous system (CNS)? 28. What is the role of the oligodendrocytes? Oligodendrocytes provide support and produce the myelin sheath, which insulates and speeds up signal transmission along axons in the CNS. 29. What is the Microglia cells function as the immune cells of the CNS, role of microglia protecting against pathogens and removing debris or cells? damaged cells. 30. What organs are brain and spinal cord surrounded and protected by the meninges? 31. What layers form Dura mater: The outermost and toughest layer, providing the meninges? protection and stability to the brain and spinal cord. Arachnoid mater: The middle layer, located between the dura mater and the pia mater. It is web-like in structure and contains the cerebrospinal fluid. Pia mater: The innermost layer, closely adherent to the surface of the brain and spinal cord, providing support and nourishment to these structures. 32. what structure connects the cerebral hemispheres corpus callosum 33. What three struc- Medulla oblongata: Located at the base of the brainstem, tures form the the medulla oblongata regulates vital functions such as brainstem? What breathing, heart rate, and blood pressure. Pons: Situated above the medulla oblongata, the pons 6/8 are their functions? serves as a bridge connecting different parts of the brain. It is involved in regulating sleep, respiration, swallowing, and facial movements. Additionally, it plays a role in transmitting signals between the cerebellum and the rest of the brain. Midbrain (Mesencephalon): The midbrain is located above the pons and serves as a relay center for auditory and visual information. 34. what 4 structures thalamus, hypothalamus, hippocampus, amygdala make up the limbic system? 35. What does grey matter mainly contain? Cell bodies, dendrites and unmyelinated axons responsible for processing and integrating information in the brain. 36. What does white myelinated axons matter mainly contain? 37. What neurotransmitter is released by motor somatic neurons? What receptor does this neurotransmitter bind to in the target organ? What is the effect on the target organ? Motor somatic neurons release acetylcholine (ACh) as their neurotransmitter. This neurotransmitter binds to nicotinic acetylcholine receptors (nAChRs) located on the skeletal muscle fibers of the target organ. The binding of ACh to these receptors results in the depolarization of the muscle cell membrane, leading to the generation of an action potential and subsequent muscle contraction. Therefore, the effect on the target organ (skeletal muscle) is muscle contraction or motor activity. 38. What effect does activating the Alpha adrenergic receptors have? Activation of alpha adrenergic receptors causes smooth muscle contraction in many tissues, leading to effects such as vasoconstriction (narrowing of blood vessels), contraction of the iris radial muscle (resulting in pupil dilation), and contraction of the smooth muscle in the bladder and urethra (promoting urinary retention). There are two main 7/8 subtypes of alpha adrenergic receptors: alpha-1 adrenergic receptors and alpha-2 adrenergic receptors. 39. what effect does activating the alpha adrenergic receptors have? Beta-1 adrenergic receptors are primarily found in the heart, where their activation increases heart rate (positive chronotropic effect) and contractility (positive inotropic effect). Beta-2 adrenergic receptors are primarily located in smooth muscle, particularly in the bronchioles of the lungs and blood vessels in skeletal muscle. Their activation leads to relaxation of bronchial smooth muscle (bronchodilation) and vasodilation, which increases blood flow to skeletal muscle. 40. What neurotransmitter is released by the post-ganglionic parasympathetic neurons? What receptor does this neurotransmitter bind to in each target organ? What is the effect in each target organ? In each target organ, acetylcholine binds to muscarinic acetylcholine receptors (mAChRs), which are a subtype of cholinergic receptors. These receptors are present on various tissues throughout the body, including smooth muscle, cardiac muscle, and glands. Smooth muscle: Activation of muscarinic receptors on smooth muscle typically leads to relaxation. Cardiac muscle: Acetylcholine binding to muscarinic receptors in the heart results in a decrease in heart rate and a decrease in the force of contraction. This leads to a decrease in cardiac output and a decrease in blood pressure. Glands: Muscarinic receptor activation stimulates glandular secretion. 8/8