Chapter 14 Muscular System Notes PDF

Chapter 14 Muscular System Notes Recall: 3 Basic Muscle Types – complete review worksheet in Brightspace and add to notes Functions of Muscle 1. 2. 3. 4. Properties of Skeletal Muscle Activity 1. _________________...

Chapter 14 Muscular System Notes Recall: 3 Basic Muscle Types – complete review worksheet in Brightspace and add to notes Functions of Muscle 1. 2. 3. 4. Properties of Skeletal Muscle Activity 1. ____________________ = to receive and respond to stimuli 2. ____________________ = ability to shorten forcibly when stimulated 3. ____________________ = ability to recoil after stretch 4. ____________________ = ability to stretch Connective Tissue Wrappings of Skeletal Muscle – label the following diagram of skeletal muscle tissue Connective tissue sheaths: - Made of dense regular CT - Form _____________ = connect muscle to bone and transfer contractile force to bone for movement  Chapter 14 Muscular System Notes Recall: 3 Basic Muscle Types – complete review worksheet in Brightspace and add to notes Functions of Muscle 1. 2. 3. 4. Properties of Skeletal Muscle Activity 1. ____________________ = to receive and respond to stimuli 2. ____________________ = ability to shorten forcibly when stimulated 3. ____________________ = ability to recoil after stretch 4. ____________________ = ability to stretch Connective Tissue Wrappings of Skeletal Muscle – label the following diagram of skeletal muscle tissue Connective tissue sheaths: - Made of dense regular CT - Form _____________ = connect muscle to bone and transfer contractile force to bone for movement  Chapter 14 Muscular System Notes Recall: 3 Basic Muscle Types – complete review worksheet in Brightspace and add to notes Voluntary Stricted , Involuntaryy , Stricted Involuntary , n o n - st r i c te d Skeletal Smooth Cardiac Functions of Muscle 1. movement 2. Maintain posture 3. Stabilizing joints 4. Produce heat > - maintain body temp Properties of Skeletal Muscle Activity 1. ____________________ Irritability = to receive and respond to stimuli 2. ____________________ Contractility = ability to shorten forcibly when stimulated 3. ____________________ Elasticity = ability to recoil after stretch 4. ____________________ Extensibility = ability to stretch Connective Tissue Wrappings of Skeletal Muscle – label the following diagram of skeletal muscle tissue Blood Vessel muscle cell/fiber (Endomysium Connective tissue sheaths: fascicle - one group of muscle cells (Perimysium) - Made of dense regular CT - Form _____________ Tendon = connect muscle to bone and transfer contractile force to bone for movement groups (Epimysium o f fascicles Bone Tendon  Microscopic Anatomy of Skeletal Muscle – Label the following diagram key Components > - one muscle cells/fibers has many cells > Cells are long Cylindrical - , > Myoglobin-Oxygen - storage Glycogen-stores > - energy > - More M i to c h o n d r i a (more ATP) > - Sarcollema-membrane > - inward extension of membrane = T-tubule Mitochondria > - Sarcoplasm - intracellular fluid > Sarcoplasmic reticulum Smoother - - Terminal > Terminal Listernae - - end sacs that store Calcium Cisternae Sarcolemmua Sarcolemma Sarcoplasm myofibril = - Terminal Sarcoplasmic Reticulum T-tubules *Complete the worksheet on microscopic structure of skeletal muscle posted in Brightspace and add to notes* The Myofibril - 1 muscle fibre/cell has 100’s to 1000’s of myofibrils made of chains of ________________(functional Sarcomeres unit of muscle) (Spaces 22-discs)between - Sarcomeres are divided by ___________________ 2-discs - Sarcomeres have specific arrangement/pattern of proteins called _________________ Myofilaments = _____________ ac tin and _____________ myosin - Myofilaments are arranged into bands: 1. _____________: A-band dark band containing actin and myosin E-band - 2. _____________: light band containing actin * think hands metaphor Myofilaments: Myosin and Actin MYOSIN (Thick filament) ACTIN (Thin filament)..... PrAotect BindingSiti n - contains contractile proteins - protein of each myosin head has two binding sites: - chain of proteins (G-proteins), each with site for _____________________ myosin 1) one to attach to _____________ and ac tin form a cross-bridge - binding site normally covered by long, thin protein called__________________ Tropomyosin 2) contains _______________ ATP-ase (symto bra to bind an ATP molecule (energy needed to - attached to tropomyosin is ____________, Troponin attach and release myosin head) which has an affinity for calcium Excitation-Contraction Coupling Step One: Nerve stimulus to muscle A muscle must be stimulated by a ____________in order to contract motor neuron A motor neuron has axon terminals to many muscle fibres/cells The muscle fibres of a single motor neuron are spread out throughout the muscle (not clustered) so stimulation of a motor unit causes weak contraction of ____________________________________ entire muscle One motor n e u ro n + a l l the cells it stimulates = motor unit Types of Motor Control (Paccuracy ↓ Strength + Ex. eyes 1. ___________ Fine motor control = when one motor neuron controls 3-6 fibres/cells to give ____________________ m o re accuracy but less strength ex. Control of eyes and fingers 2. ___________ Gross motor control = when one motor neuron controls up to 1,000 fibres/cells to give ________________ but less accuracy. Ex using quadriceps muscle The Neuromuscular Junction and Excitation of Muscle Step 1: nerve impulse travels down motor neuron to axon terminal Step 2: nerve impulse triggers movement of calcium from ECF to ICF of axon terminal Step 3: calcium triggers release of acetylcholine (ACh) into synaptic cleft (excites muscles , neurotransmitter) Step 4: Ach binds to receptors on sarcolemma to trigger opening of Na+ channels Excitation-Contraction Coupling Cont’d Step 5: action potential occurs in sarcolemma and travels down t-tubule Step 6: action potential travels past terminal cisternae of sarcoplasmic reticulum, to release ca2+ into sarcoplasm The Sliding Filament Theory Step 7: Ca2+ binds to troponin, which moves tropomyosin off myosin-binding site on actin Step 8: ATP binds to myosin head, myosin head changes shape (“cocked”) and myosin binds to actin (cross-bridge formed) Step 9: actin `slides’ past myosin and sarcomere shortens Step 10: another ATP binds to myosin head and head detaches from actin (cycle continues) Multiple attachments and detachments of myosin heads leads to shortened muscle (a contraction) and process occurs in all Graded Responses sarcomeres of Muscle at same time Contraction as stimulus travels down sarcolemma Graded response: Different degrees S keletal of muscle contrac tion (different forces How Graded Contractions are Produced 1. Change _____________of frequency stimuli (impulse): how fast a stimulus is sent to a muscle (Summation tension building on normal no re st (muscle contracted all the time) tetnus 2. Change ____________of Strength stimuli (impulse): recruitment Muscle force depends upon the number of fibers stimulated More fibers contracting = more muscle tension More force = stimulate/recruit more motor units! Muscles can continue to contract unless they run out of energy!  Energy for Muscle Contraction Initially, muscles use stored __________ Th for energy but there is only ____________ - 4-6 Seconds seconds worth of this and so other pathways are needed to get energy. O going to enough muscle cells ? Y ↳ No : Yes ? Anaerobic Aerobic Glycolysis only 2 Atplymoose Respiration ↳ Lactic acid produced 36-38 ATP/glucose CP ADP ) [usprate Donate Phosphate Creatine Phosphate Creatine ATP 5x as much Cp as ATP ________________= fatigue muscle physiological inability for muscle to contract ________________ Oxygen debt = oxygen `owed’ to liver cells to rid lactic acid; to muscle cells to restore ATP and CP Increasing acidity (from lactic acid) and lack of ATP causes the muscle to contract less (Breathe faster , more oxygen to give liver to produce ATP) Muscle Tone Muscle tone is the maintenance of partial contraction of a muscle when the muscle is at rest Why is muscle tone needed and what controls muscle tone? - Helps maintain posture Not Signals coming from brain - - Reflexes coming from Spinal cord Muscles have at least 2 points of attachment 1) Origin - > on least movable bone of joint 2) Insertion > - On the m o re moveable bone of joint the # When muscles contracts , the insertion moves towards Origin