Exam 2 Study Guide Spring 2024 PDF

Exam 2 Study Guide. This is a study guide, which includes the most important concepts covered for exam 2. Chapter 11-Nervous System  Central Nervous System Components o Brain, Brain stem (3 parts), and Spinal Cord. Understand the importance of the motor cortex and central mo...

Exam 2 Study Guide. This is a study guide, which includes the most important concepts covered for exam 2. Chapter 11-Nervous System  Central Nervous System Components o Brain, Brain stem (3 parts), and Spinal Cord. Understand the importance of the motor cortex and central motor neurons. Understand how the central and peripheral somatic motor neurons communicate via a synapse in the spinal cord.  Neurons (Nerve Cells)  Structure  Soma (hillock), dendrites, axon, and axonal terminals o Function of each part (which part has receptors for neurotransmitters, conducts the action potential, release neurotransmitters).  Neurotransmitters: location, release, and effects (stimulatory or inhibitory) on their receptors in effector organs.  The Action Potential o Resting Membrane Potential (RPM): Normal values. Factors that influence RMP (Na+ and K+ concentration in extracellular and intracellular fluids). o 1. Depolarization: Na+ channel opening and closing at beginning and end, Na+ facilitated diffusion causes the change in polarity. o 2. Repolarization: K+ channels opening and closing at beginning and end, K+ facilitated diffusing and effects on polarity, and the effect of the Na+/K+ pump at the end of repolarization.  The Synapse o Presynaptic and Postsynaptic Neurons communication via neurotrasmitters. o Role of Ca2+ in the axon terminal to release neurotransmitters o Role of the Synaptic Cleft o Neurotransmitter binding to receptors in postsynaptic neuron receptors o Removal or inactivation of the neurotransmitter by an enzyme.  Nervous system o Central and peripheral Motor Neurons.  Understand the process of voluntary movements.  Activation (action potential) of the motor cortex,  Propagation (movement) of action potential to the axon terminal of central motor neuron.  Know what is and where the decussation of pyramids occurs.  How electrical signals (action potentials) are conducted in central motor neurons to the peripheral motor neurons in the spinal cord  The synapse between central and peripheral motor neurons in the spinal cord,   Transmission of action potential from the soma of the peripheral somatic motor neurons to the axon terminal in the neuromuscular junction.  Understand the release of neurotransmitters from vesicles in the axon terminals to the synaptic cleft in synapse and neuromuscular junction.  Events in the neuromuscular junction. Release of Ach, binding of Ach to receptor in the Na+ channel, production of action potential, removal of Ach and inactivation by acetylcholinesterase. Chapter 9-Skeletal Muscle  Structure of Skeletal Muscle o Sarcolemma, sarcoplasm, myofibril, T-tubule, sarcoplasmic reticulum (cisterna), actin and myosin filaments  Sarcomere o Structure  Z-disc, I band, A-band (filaments in the I and A bands) o Myofilaments  Actin  Components of the actin (G-actin, tropomyosin, and troponin).  G-actin, tropomyosin, troponin, troponin subunits (TnI, TnC, TnT). Role of the Tn subunits for muscle relaxation and contraction.  Myosin  Tails, Heads, ATPase enzyme. Role of myosin heads and ATPase for muscle contraction.  Contraction of Skeletal Muscle o Understand the role of sarcolemma, sarcoplasmic reticulum (cisternae), T- Tubules, calcium concentration in sarcoplasm and sarcoplasmic reticulum in muscle contraction and relaxation. o Neuromuscular junction  The structure of the NMJ can be divided in 3 main parts (components): 1) Axon terminal (has Ach), 2) synaptic Cleft, and 3) sarcolemma with ACh receptors/Na+ channels. Understand the role of acetylcholinesterase for removal of Ach and muscle relaxation. o Excitation-Contraction Coupling. Understand the steps from release of Ach by the somatic motor neuron to muscle contraction and relaxation.  Propagation of signal through sarcolemma, T-tubule, Ca2+ release from sarcoplasmic reticulum. Calcium in sarcoplasm going to bind its receptor (TnC), TnT and tropomyosin interaction to uncover active sites and start muscle contraction. Myosin head interaction with actin’ active sites,  release of Pi from ATP by myosin ATPase to provide energy for contraction, the power stroke, Muscle relaxation after contraction:  Removal of Ach from receptors in sarcolemma  Removal of Ca2+ from the sarcoplasm back to the sarcoplasmic reticulum to relax muscle,  Blocking of actin’s active sites  Need of a new ATP to detach myosin heads from active sites  ATP to pump Calcium back to sarcoplasmic reticulum o Sliding Filament Model of Contraction. Understand the sliding of filament and change in I-band length. This is linked to the power stroke pushing actin filaments to the center of the sarcomere. o Motor Units. Know the components of a motor unit.  Skeletal Muscle Twitch o Tension (force or strength) and time (speed) of contraction. Differences in speed of contraction, force production and size between type I and II muscle fibers.  Muscle Fiber Types characteristics o Type 1 and Type 2 o Understand differences in speed of contraction, force production, and fiber size. o Be able to differentiate them by their characteristics. Chapter 16-The Autonomic Nervous System (ANS) Autonomic Nervous System is divided in sympathetic and parasympathetic. ANS anatomy: location of preganglionic parasympathetic neurons to the atriums and to the abdominal organs. Location of preganglionic sympathetic neurons (spinal cord) to the heart, and adrenal medulla. Postganglionic parasympathetic neurons to myocardium in atriums. Postganglionic sympathetic neurons to myocardium in atriums and ventricles and vascular smooth muscles in blood vessels. ANS physiology: Neurotransmitters secreted by preganglionic and postganglionic autonomic neurons.  Understand the effects (stimulatory [+] or inhibitory [-]) of acetylcholine (Ach) and catecholamines (norepinephrine and epinephrine) on different cells of effector organs mentioned above. Understand the effects of catecholamines on adrenergic receptors. Understand the effects of acetylcholine (Ach) on cholinergic receptors. o The stimulatory effect of Ach on postganglionic autonomic (parasympathetic and sympathetic) neurons and adrenal medulla. o The inhibitory effect of Ach from postganglionic parasympathetic neurons on the myocardium of atriums. o The stimulatory effect of catecholamines (norepinephrine and epinephrine) from postganglionic sympathetic neurons and adrenal medulla on myocardium of atriums/ventricles and vascular smooth muscles.