Muscles / bio 160
Terms
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- Androstenedione
- occurs naturally in the body when it is synthesizing the sex hormone testosterone.
- creatine
- 1) performance enhancer 2)a short chain of amino acids 3) muscle cells use it as a quick energy source when they must contract hard and fast 4) evidancethat excessive creatine damages the kidneys
- Muscular system
- workings of skeletal muscles
- Muscle Cells
- 1) generate force by contracting. 2) bundled together by connective tissue that extends past them to form tendons
- skeletal muscles
- 1) attach to and interact with bones. Only skeletal muscle interacts with the skeleton to move the body, its limbs, or other parts. 2) helps stebilize joints between bones, and generate body heat 3) contains bundles of muscle cells.
- Tendons
- 1) a cord or strap of dense connective tissue, attaches a muscle to bone, attaches a muscle to bone 2) tendons make joints more stable by helping keep the adjoining bomes preperly aligned. Tendons often rub against bones, but they slide inside fluid-filled sheaths that help reduce the friction.
- sheaths
- your knees , wrists, and finger joints have sheaths
- origin
- 1) one end of muscle is attached to a bone that stays relatively motionless durring a movement
- insertion
- 1) one end of muscle is attached to the bone that moves most
- Bones (and therefore other body parts) move when____________pull on them
- skeletal muscles
- __________strap skeletal muscles to bone
- Tendons
- Muscles can work together to ____1____ a movement, or the action of one can_____2______or______3_______the action of another.
- 1)generate 2)oppose 3)reverse
- excitability
- muscle tissue can use an ion gradient to both receive and respond to a stimulus
- contractillity
- contraction or the ability to shorten
- extensibility
- the ability to be stretched
- elasticity
- the ability to return to its original shape
- each muscles is composed of elongated muscle cells called________which contains _________, __________, __________, _________, __________
- Muscle fibers, sarcolemma (plasma membrane), sarcoplasm (cytoplasm), sarcoplasmic reticulum (the er), transvers tubules, traids (t-tubules and sr on eaither side)
- * Muscle fibers are further divided into __________
- myofibrils
- *Myofibrils are composed of the myofilaments ___________ and_________
- actin, myosin
- myofilaments are arranged into____________
- sarcomeres (not in smooth muscle
- actin
- a golbular contractile protein, In muscle cells, actin interacts with another protein, myosin, to bring about contraction.
- **actin and myosin arrangements
- 1) actin (thin) filamen 2) actin is a double stranded protein that entwines helically. 3) contains myosin binding sites 4) troprnin/tropomyosin protein complex adhere to actin and block myosin binding
- *troponin / tropomyosin complex
- obscures myosin binding sites on actin. The binding of calcium to troponin alters the shape of this complex revealing the myosin binding sites
- myosin
- a contractile protein. In muscle cells, it interacts with the protein actein to bring about contraction
- *_________(_____)______ is shaped like a golf club head that functions in forming a crossbridge with an actin binding site
- Myosin (thick) filament
- *the myosin head contains an _________________
- ATP binding site
- myosin crossbridges attach to the actin binding site and a ____________ occurs. This causes the ____molecules to slide towards the opposite ________and the_________shortens. The energy comes from_________
- powerstroke, Z-disk, sarcomere, APT
- *_______ must be present for actin / myosin binding
- calcium
- **muscle fibers contract when they receive a stimulus from the __________
- nervous system
- **the axon of the _________has terminal axons that come close to the sarcolemma but that leave a small gap
- motor neuron
- ***the junction between the sarcolemma and axon terminal is called the ____________or_______________
- motor end plate, neuromuscular junction
- **the synaptic end bulb contains many tiny sacs termed ____________
- synaptic vesicles
- **synaptic vesicles contain a neuro- transmitter called _________________
- acetylcholine (Ach)
- **the _____________ refers to the gapbetween the end bulb and the sarcolemma
- synaptic cleft
- **_______________increase the surface are for A Ch binding
- subneural clefts
- **___________are integral proteins located in the sarcolemma and function as ligand Na gates
- A Ch
- ATP(adenosine triphosphate)
- a nucleotide composed of adenine, ribose, and three phosphate groups. As the main energy carrier in cells, it directly or indirectly delivers energy to or picks up energy from nearly all metabolic pathways.
- **neuromuscular junction
- chemical synapse between axon terminals of a motor neuron and a muscle cell
- motor neuron
- a neuron that delivers signals fron the brain and spinal cord that can stimulate or inhibits the body's effectors (muscles, glands, or both).
- acetylcholine (A Ch)
- a neurotransmitter that can excite or inhibit various target cells in the brain, spinal cord, glands, and muscles.
- **synapse occurs** a _______reaches the axon terminal
- nerve impulse
- **synapse occurs** the end bulb becomes permeable to ________
- calcium ions
- **synapse occurs** calcium ions attach to ______________causing them to move towards and merge with the end bulb
- synaptic vesicles
- **synapse occurs** the synaptic vesicles release ____________ into the synaptic cleft
- acetylcholine (Ach)
- **synapse occurs** acetylcholine binds to receptors ligand gated Na receptors located in the ________ . This causes _______________ to open causing a massive influx of Na into the muscle cell. This causes an _____________within the muscle fiber.
- subneural clefts, Na channels, action potential
- **physiology of contraction** an action potential travels along the sarcolemma, across the T-tubules and into the _______
- triads
- **physiology of contraction** the ___ releases calcium into the sarcoplasm
- SR
- **physiology of contraction** calcium binds to ___________
- troponin
- **physiology of contraction** troponin
- calcium binding causes the troponin / tropomyosin complex to alter its shape and the myosin binding sites on actin are revealed
- **physiology of contraction** ATP is already attached to myosin and now the nyosin head binds with ___________
- actin
- **physiology of contraction** myosin, using the power provided by its ATP, pulls ________ towards itself (powerstroke). ATP is degraded in this process to ________and____
- actin, ADP, P
- **physiology of contraction** the myosin head cannot release from actin untill another ATP attaches to _______
- myosin
- **cessation of contraction**** Ach is destroyed by an enzyme located in the synaptic cleft called _______________
- acetylecholinesterase ( erase / stop contraction)
- **physiology of contraction** calcium ions are actively transported back into the sarcoplasmic reticulum by _______________. ___________ and __________ are two proteins that aid this process
- calcium active transport pumps, calsequestrin and calcium ATPase
- **physiology of contraction** ____________/__________ are anticholinesterases which inhibit breakdown of Ach causing prolonged tetanic contractions. ___________ inhibits the action of Ach at postganglionic sites.
- Organophospates / nerve agents ( pestisides ), atropine ( to restart the heart , block acetylecholine )
- ______ supplies the energy required for contraction
- ATP
- a high energy molcule stored in muscle tissue, called __________________, allows for the regeneration of spent ATP (ADP + P) by donating its high energy phosphate to ADP.
- phosphocreatine (phosphagen system relyes on phosphocreatine)
- _________ occurs in large concentrations in muscle and is taken ion large amounts by bodybuilders
- creatine (CH3, methylated arginine / glycine complex)
- energy for contraction - glycogen
- lactic acid production - a storage polysaccharide that can be readily broken down into glucose subunits.
- energy for contraction - glucose
- is stored as glycogen inside muscle and liver cells