Lecture 14 Neuromotor Systems PDF

Class code: Neuromotor Systems Lecture 1 of Dr Jorn Cheney SEATS [email protected]  Sensi Neuromotor Systems ng Lecture 1 of Control MotionInte...

Class code: Neuromotor Systems Lecture 1 of Dr Jorn Cheney SEATS [email protected]  Sensi Neuromotor Systems ng Lecture 1 of Control MotionIntegrative neuroscience strategy Muscl e Dr Jorn Cheney [email protected]  Sensi ng Medicine Technolo Control Motion gy strategy Evolutio n Muscl e Learning Neurones (UK) objectives Motor Neurons (US) Explain why muscle cells are elongate, and why they contract along their long axis. Understand that muscles actively shorten and passively lengthen Explain how signals from the nervous system produce muscle activity. They do not explicitly control movement/position Sensi ng Control Motion strategy Muscl e  Signposting: Practical C Muscular reflexes and electricity 1) The role of electricity in conducting an action potential down a motor neurone 2) The role of electricity as an excitatory signal to a muscle cell 3) The role of sensory organs (signalling using electricity/action potentials) in eliciting muscular contractions Function Interfacing with Macroscopic structure muscle Microscopic structure Control Where we can we interface  Skeletal Muscle Structure Latin: Sarco- & Myo- = Epimysiu Fascicle “Muscle” m Fibre Myofibril Muscle Belly Sarcolem ma Tendon Endomysium Perimysium  Myofibri Sarcolemm a l Myofibril Myofilaments: actin & myosin Transverse Longitudinal section section High magnification 8  Activating Latin: Sarco- & muscle Myo- = “Muscle” T Tubule Ca 2+ Voltage-gated calcium channel Sarcoplasmi (protein complex) c Reticulum Myofibril (S.R)  Activating Latin: Sarco- & muscle Myo- = “Muscle” T Tubule Voltage-gated calcium channel Sarcoplasmi (protein complex) c Reticulum Ca Myofibril 2+ (S.R)  Activating Thin filaments Thick filaments Latin: Sarco- & muscle Myo- = “Muscle” T Tubule Voltage-gated calcium Myofibril channel Sarcoplasmi (protein complex) c Reticulum Ca 2+ (S.R)  Types of muscle “contraction” scle ‘contraction’ = muscle activation uscles produce only contractile force Isometric: Load = Force (muscle) Concentric: Load < Force (muscle) Eccentric: Load > Force (muscle)  Questions Correctly organise the following 7 steps involved in conducting a signal from nerve to muscle 1) Vesicles of Acetylcholine fuse to the motor neurone membrane 2) Voltage-gated sodium channels open along the sarcoplasmic membrane 3) Calcium is released into the sarcoplasmic reticulum 4) Action potential travels along myelinated motor neurone. 5) Ligand-gated channels activate allowing substantial sodium to enter the cell and some potassium to exit 6) Acetylcholine diffuses across the extracellular matrix 7) Calcium enter motor neurone  Answer Correctly organise the following 7 steps involved in conducting a signal from nerve to muscle 1) Action potential travels along myelinated motor neurone. 2) Calcium enter motor neurone 3) Vesicles of Acetylcholine fuse to the motor neurone membrane 4) Acetylcholine diffuses across the extracellular matrix 5) Ligand-gated channels activate allowing substantial sodium to enter the cell and some potassium to exit 6) Voltage-gated sodium channels open along the sarcoplasmic membrane 7) Calcium is released into the sarcoplasmic reticulum At the neuromotor junction: Questions At what stage can the signal be manipulated/measured through 1) Specific chemical interactions? 2) Electrical interaction? Working extracellularly is easier and less likely to damage the cell. Which stages can we manipulate through perturbing the extracellular matrix? The 7 steps involved in conducting a signal from nerve to muscle A) Action potential travels along myelinated motor neurone. B) Calcium enter motor neurone C) Vesicles of Acetylcholine fuse to the motor neurone membrane D) Acetylcholine diffuses across the extracellular matrix E) Ligand-gated channels activate allowing substantial sodium to enter the cell and some potassium to exit F) Voltage-gated sodium channels open along the sarcoplasmic membrane  Muscle needs to be controlled The signal to a motor neurones is basic. The signal does not determine Length Force Speed Force (F/F0) The signal to a motor neurone: Is a “twitch” request  Organization of neuromotor tissues “Indirect control” of skeletal “Excitatory” muscle function Invertebrates “Inhibitory” Neuroscience 4th ed.– Purves et a Organization of neuromotor tissues Neuroscience 4th ed.– Purves et a Electromyography (EMG) tells us if/when muscles are activating  T Tubule Voltage-gated calcium channel Sarcoplasmi (protein complex) c Reticulum Ca Myofibril 2+ (S.R) 20 Learning objectives Motor Explain why muscle cells are elongate, and why they contract along their long axis. Understand that muscles actively shorten and passively lengthen Explain how signals from the nervous system produce muscle activity. They do not explicitly control movement/position  Signposting: Practical C Muscular reflexes and electricity 1) The role of electricity in conducting an action potential down a motor neurone 2) The role of electricity in conducting an excitatory signal to a muscle cell 3) The role of sensory organs (signalling using electricity/action potentials) in eliciting muscular contractions  Further reading Dynamic Neural Control of Insect Muscle Metabolism Related to Motor Behavior. Review literature. Amazing motor-control mechanisms in insects. Physiology Motor neuron columnar fate imposed by sequential phases of Hox-c activity. Primary literature. Understanding the genetics organising the spinal cord. Nature Low-power microelectronics embedded in live jellyfish enhance propulsion. Primary literature. Externally controlling the locomotion of a jellyfish. Science Advances Neuroscience by Dale Purves, et al. Textbook. Skim for the relevant sections