E109 Lecture 6: Intro to Skeletal Muscles Fall 2024 PDF

Spinal Cord Anatomy: Ganglia outside CNS, Nuclei within same.itsfaies I c c's onoutsideofCns Visceral sensory nuclei Somatic sensory...

Spinal Cord Anatomy: Ganglia outside CNS, Nuclei within same.itsfaies I c c's onoutsideofCns Visceral sensory nuclei Somatic sensory nuclei Dorsal root Dorsal ganglion horn Autonomic Lateral efferent horn Ventral nuclei horn Ventral root Somatic motor nuclei Figure 9-7b Wrapping up Lecture 5: Autonomic Pathways Somatic motor Parasympathetic Sympathetic Adrenal sympathetic pathway pathway pathways pathway CNS CNS CNS CNS ACh Nicotinic receptor Adrenal cortex Adrenal medulla Ganglion E ACh Nicotinic Ganglion receptor NEonly receptor NE NEOVE ACh B1 Muscarinic receptor Autonomic effectors: Blood vessel Skeletal 1 receptor Smooth and cardiac muscles muscle ACh Some endocrine and exocrine E Nicotinic glands receptor Some adipose tissue 2 receptor B Fonly Response to Stimulus Reflex response Homeostatic response feedback feedback Sensory input Sensory input hypothalamic Somatic & visceral receptors sensory neurons Integration pons, medulla, hypothalamus Somatic Autonomic Endocrine response motor response response Thermoregulation afferent sensory neuron interneuron ascending tract descending tract somatic motor neuron efferent autonomic neuron Hypothalamus skeletal muscle nicotinic receptor ACh tunica externa Smooth Muscle NE endothelium adrenergic receptor Review The hypothalamus serves a critical function in maintaining homeostasis Spinal reflex are fast involuntary actions without direct integration by brain Homeostatic reflexes are slower often involve the autonomic nervous system The autonomic nervous system has two branches (parasympathetic and sympathetic) Within the CNS control of the two branches of are spatially segregated The two branches of the ANS affect the same target cells but produce antagonistic effects by interacting with different receptors on the same cell E109 lecture 6: Intro to skeletal muscles Bio Sci Peer Tutoring Review Friday 13 Oct 5-6:50PM in ELH 100 Larc Review Monday 16 Oct 7PM ALP 1600 Lecture 6: Learning Objectives Learn the basic architecture of muscles Observe that the neuromuscular junction is a synapse between motor neurons and muscle cells Understand that excitation-contraction coupling is the conversion of an electrical signal in the sarcolemma (membrane) into a Ca+2 signal in the cytoplasm Learn that calcium release from the SR is a critical regulatory step in contraction Understand that ATP is required for detachment of cross bridges and by Ca+2 pumps used to move calcium into the SR Three Types of Muscle Skeletal Cardiac Smooth Attached to Skeleton Heart Internal organs/vessels Striated Striated Smooth Sarcomere Sarcomere Oblique Bundles Multinucleated Uninucleated smallery Uninucleated Fastest avifponse Intermediate Slowest Somatic motor Autonomic Autonomic Fundamental Function Neural movingaroundproduces heatduetoheat Information loss Mechanical Energy (force and displacement) Skeletal Muscle Triceps muscle contracts (extensor) Triceps Biceps muscle triabi work in muscle relaxes opposite times relaxes Biceps muscle when bi is contracted contracts (flexor) tri is relaxed Organization of Skeletal Muscle Skeletal muscle Tendon Nerve and blood vessels Connective tissue Muscle fascicle: bundle of fibers Connective tissue Nucleus Muscle fiber Ultrastructure of Muscle cycle 9 Sarcoplasmic Mitochondria reticulum calciumstorehouse Nucleus T-tubules Myofibril Sarcolemma membrane my Ultrastructure of Muscle myofibrial Sarcomere Z disk contratileunit Z disk Titin Z disk Z disk Thin filament M line Myosin Ultrastructure of Muscle M line Thick filaments Myosin heads Hinge Myosin tail region Myosin molecule Ultrastructure of Muscle Thin filaments Titin bindcalcium GTroponin Nebulin Tropomyosin likerope acts as G-actin molecule a safleygaund Actin chain a The contraction cycle Summary of Muscle Contraction formationofactionpotential electricalevent ATP thispsterreq response ADP The Neuromuscular Junction Somatic motor neuron The neuromuscular junction ATP ADP Axon terminal Motor end plate recieves signal from neuron The Neuromuscular Junction Somatic motor neuron Axon terminal ATP ADP Ca2+ Ca2+ Action potential ACh Acetyl + choline Voltage-gated Ca2+ channel Closed channel Open channel K+ Skeletal ACh Na+ AChE muscle fiber Motor end Nicotinic plate receptor K+ Na+ lotsofsodiumin Excitation Contraction Coupling ATP ADP actionpoafftjafhfotmm.gov Han ca2t to goincell DHPR: Dihydropyridine receptor RyR: Ryanodine receptor The Calcium Signal: activation ATP ADP The Calcium Signal: relaxation ATP ADP The Calcium Signal ATP ADP Contraction cycle Rigor state: Myosin bound to actin G-actin molecule ADP lost. The cross-bridge enters the ATP binds to myosin allowing transient Rigor state detachment. Myosin in low E state. Myosin binding sites 4 Myosin filament ADP ATP 3 5 Pi lost. Myosin forms strong bond with ATP hydrolyzed. Myosin assumes high actin and performs the power stroke. E state & forms weak bond with actin. Ca2+ ADP ATP Pi Pi 1 ADP 2 state