Know the characteristics of muscle Flashcards
Muscle (fiber) cells are elongated Contraction is due to the movement of myofilaments Prefix: myo: muscle mys: muscle sarco: flesh (217 cards)
Know the characteristics of muscle
Muscle (fiber) cells are elongated Contraction is due to the movement of myofilaments Prefix: myo: muscle mys: muscle sarco: flesh
List and describe the functions of the muscular system
Produce movement
Maintain posture
Stabilize joints
Generate heat
Cardiac Muscle
Only in the heart Involuntary Joined to other cells at intercalated discs Has striations Usually has 1 nucleus
Skeletal Muscle
Voluntary Multinucleated Striations Attached to bone by tendons Cells are bundled and surrounded by connective tissue
Smooth Muscle
Has no striations
Involuntary
Spindle-shaped
Single nucleus
the functions and the sequence of the connective tissue coverings of a muscle
Endomysium- innermost layer of connective tissue (muscle fiber)
Perimysium- middle layer of connective tissue (fascicle)
Epimysium- outermost layer of connective tissue (muscle)
where the nuclei and mitochondria are found in muscle cells
Nuclei- muscle fiber, just beneath sarcolemma
what causes the regular striations in muscle tissue
Action potential arrives at axon branches of a motor neuron
Synaptic vesicles containing Ach fuse with the neuron membrane
Acetylcholine is released into the synaptic cleft
Ach binds to receptors on the cells motor end plate
Bound receptor creates action potential in muscle cells
Mitochondria make neurotransmitters and provide ATP
Describe the ions that move into and out of muscle fibers and create the action potential necessary for contraction to occur
ATP- (ADP+energy) Attaches and energizes the myosin head
Calcium- (attaches to actin) Active site on the actin is exposed due to the binding of Ca2+
Power stroke: myosin head pivots, pulling actin towards the m line (ADP+P are released)
Detachment: As new ATP attaches to myosin head, the cross bridge detaches
Myosin resets(return stroke): ATP->ADP released energy recocks the myosin to prepare for the next stroke
Compare and contrast the structures and regions found in relaxed muscle fiber with those of a contracted muscle fiber
Z-disc: Stays the same length, moves closer together H-zone: Disappears Sarcomere: Shortens Myosin: Stays the same length Actin: Stays the same length I-band: Smaller A-band: Stays the same Muscle: Shortens
Sequence the structures of a muscle from superficial to deep
Epimysium Muscle Perimysium Fascicle Endomysium Muscle fiber Myofibril Sarcomere
structures of thin myofilaments
Actin
Troponin
Tropomyosin
Molecules strung together like beads to form 2 fibrous strands that wrap around each other
structures of thick myofilaments
Myosin
Shape like golf clubs, with their long shafts bundled together to form a thick filament and their “heads” sticking out from the bundle
Events of NMJ
Action potential arrives at axon branches of a motor neuron
Synaptic vesicles containing Ach fuse with the neuron membrane
Acetylcholine is released into the synaptic cleft
Ach binds to receptors on the cells motor end plate
Bound receptor creates action potential in muscle cells
Mitochondria make neurotransmitters and provide ATP
Central Nervous System
Brain & spinal cord
Process and interprets sensory input and decides action is needed
Interneurons (association neurons)
Peripheral Nervous System (PNS)
Comprised of all nerves outside brain & spinal cord
Sensory (afferent) Division
Send impulses from senses to the CNS
Motor (Efferent) Division
sends impulse from CNS to muscle/glands
Sympathetic Division
“Fight or flight”
Autonomic Nervous System
Involuntary control
Somatic Nervous System
voluntary control
Parasympathetic Division
“Rest and Digest”
Sequence the connective tissue sheaths of a nerve from superficial to deep
Epineurium
Perineurium
Endoneurium
Unipolar:
Unipolar: Exclusively sensory neurons, only 1 protoplasmic process extends from the cell body