Bio 227 Ch 09 08 Smooth Muscle
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JudyRi74 Plus on March 31, 2012
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31 terms
Terms | Definitions |
|---|---|
 What is found between smooth muscles? | A small amount of fine connective tissue called endomyosin that contains blood vessels and nerves |
| Describe the physical appearance of smooth muscle | two sheets of smooth muscles with their fibers at right angles |
| Peristalsis | alternating contraction and relaxation of muscles |
| Smooth muscles lack | highly structured specific neuromuscular junctions |
| Varicosities | bulbous swellings that release neurotransmitters in a wide synaptic cleft |
| diffuse junctions | where the neurotransmitters are released |
| caveolae | pouch like infoldings that sequester bits of fluid containing calcium ions |
| Smooth muscles have no striations and therefore | no sarcomeres |
| What is different about smooth muscle thick filaments (myosens) | heads along their entire length. |
| What is different about thin filaments on smooth muscle | No troponin complex |
| How are thick and thin filaments arranged? | diagonally |
| What are smooth muscle intermediate filaments? | smooth muscle fibers that contain the lattice-like arrangement of non-contractile intermediate filaments |
| Gap junctions of smooth muscle allow | smooth muscles to transmit action potential from fiber to fiber |
| Pacemaker cells | set the contractile pace for the entire muscle sheet |
| Three ways the contraction of smooth muscle is similar to skeletal muscle | sliding filament mechanism final trigger is a rise in calcium levels energized by ATP |
| calmodulin | calcium ions interact with this molecule to activate myosin |
| Smooth muscles take 30 times | longer to contract and relax than do skeletal muscles |
| How can contractions of smooth muscles be regulated? | nerves, hormones, or local chemical changes. |
| Some smooth muscle layers have no | nerve supply |
| stress - relaxation response | allows hollow organs to expand w/o promoting strong contractions |
| Smooth muscles have the ability to generate considerable force, even | when they are substantially stretched |
| Both skeletal and smooth muscles have the ability | to hypertrophy. |
| hyperplasia | to divide an increase in numbers |
| two types of smooth muscle | single - unit smooth muscles and multi - unit smooth muscles |
| Single - unit smooth muscles | also called visceral muscles, because it is in the walls of hollow organs |
| Single unit smooth muscles arrangement and characteristics | opposing sheets, have varicosities, exhibit rhythmic spontaneous action potential, are electrically coupled by gap junctions and contract as a unit, and respond to various chemical stimuli |
| Multi-unit smooth muscles | large airways of the lungs, in large arteries, the arrector pili muscles and the muscles that adust pupil size |
| Multiunit smooth muscles consists of | muscle fibers that are structurally independent, supplied with nerve endings, form a motor unit with a number of muscle fibers, and respond to neural stimulation with graded contractions that involve recruitment. |
| All three types of muscle tissues develop from | embryonic mesoderm cells called myoblasts. |
| Muscular dystrophy | group of inherited muscle destroying diseases that generally appear during childhood |
| Duchenne muscular dystrophy | a sex linked recessive disease that primarily hits boys between two and seven years old |
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