Lecture Chapter 10 Flashcards
Muscle
What are the four functions of muscle tissue?
Produce body movements
Stabilize body positions
Store and move substances within the body
Generate heat
What do muscle fibers arise from?
Myoblasts
What are myofibrils made up of?
Sarcomeres
What are thick and thin filaments made of?
Thick are made of myosin
Thin filaments are made of actin
What is the order of events for muscle contraction?
Nerve impulse opens Ca+ channels and Ca+ binds to vesicles
ACh is released into the synaptic cleft
ACh binds to its receptors
ACh binding causes Na+ to flood into the muscle fiber, and K+ to slowly leak out
End plate potential occurs, and causes Ca+ to release from sarcoplasmic reticulum
Ca+ binds to troponin, exposing myosin binding sites
Crossbridge formation between myosin and actin
Pull of thin fiber to overlap with thick fiber
ATP releases myosin head from actin
ATP split and myosin head is reset
What is the neurotransmitter and ion required for muscle contraction?
ACh and Ca++
What is the role of desmosomes in cardiac muscle?
Hold positions even during contraction
What is it called when muscle stimulation is so frequent, it remains contracted?
Tetany
What is the difference between isometric and isotonic contraction?
Isometric has no movement, Isotonic has movement
What is it called when all muscle cells contract together?
Synstium
What is responsible for vasodilation and vasoconstriction?
Smooth muscle
What are the steps for smooth muscle contraction?
Opening of Ca+ channels
Binding of Ca+ to calmodulin
Activation of myosin light-chain kinase
Activation of myosin head
Crossbridge formation, power stroke
What primary germ layer does muscle arise from?
Mesoderm
What is the mechanism behind Spastic Paralysis?
Constant ACh release
What is the mechanism behind Flaccid paralysis?
No ACh release
