Glossary of Biology - CH 10 - Muscles and Locomotion
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- How do protozoans and primitive algae move?
- By beating cilia or flagella
- How do cilia and flagella work?
- Cylindrical stalk of eleven microtubules-nine paired microtubules arranged in a circle with two single microtubules in the center
Move using power stroke using sliding action of microtubules
Recovery stroke is return of cilia or flagella to original position
- How do amoeba move?
- Extend pseudopodia
Advancing cell membrane extends forward, allowing cell to move
- How do longworms move?
- Muscles are arranged in two antagonistic layers: longitudinal and circular
Muscles contract against incompressible fluid within animal's tissue (termed hydrostatic skeleton)
Contraction of circular muscles causes elongation of worm
Contraction of longitudinal muslces causes shortening of worm
- How do annelids move?
- Segmented worms
Advance primarily by action of muscles on a hydrostatic skeleton
Bristles in the lower part of each segment, called setae, anchor the earthworm temporarily in the earth while muscles push it ahead
- What is an exoskeleton?
- Hard skeleton that covers all muscles and organs and some invertebrates
- Where are exoskeletons mostly found?
- Principally in arthropods (insects)
- What are insect skeletons composed of?
- What are exoskeletons composed of?
- Noncellular material secreted by epidermis
- What is a limitation of an exoskeleton?
- Growth is limited and periodic molting and deposition of a new skeleton is necessary to permit body growth
- What is cartilage?
- Connective tissue that is softer and more flexible than bone
Retained in places where firmness and flexibility is needed
- What are the two types of bone?
- Spongy Bone
- What type of tissue is bone?
- Mineralized connective tissue
- Describe compact bone
- Dense bone that does not appear to have cavaties when observed with naked eye
Bony matrix is deposited in structural units called osteons (haversian systems)
- What is an osteon?
- Bony matrix is deposited in structural units called osteons (haversian systems)
Each osteon consists of a central microscopic channel called a haversian canal, surrounded by number of concentric circles of bony matrix called lamellae
- What is lamellae?
- Concentric circles of bony matrix surrounding the haversian canal
- Describe spongy bone:
- Less dense and consists of interconnecting lattice of bony spicules (trabeculae)
Cavities filled with yellow and/or red marrow
- What are spicules (trabeculae)?
- Innterconecting lattice of bony material in spongy bone
- What does yellow marrow do?
- Yellow marrow is inactive and infiltrated by adipose tissue
- What does red marrow do?
- Active production of red blood cells
- What do osteoblasts do?
- Synthesize and secrete the organic consituents of bone matrix
Once they are surrounded by their matrix, they mature in osteocytes
- What are osteoclasts?
- Large multinucleated cells involved in bone resorption
- What is part of the axial skeleton?
- Skull, vertebral column, rib cage
- What is part of the appendicular skeleton?
- Appendages, pectoral and pelvic girdles
- What are ligaments?
- Support bone joints
- What are tendons?
- Muslcle to bone attachment
- What is the origin and insertion of a muscle?
- Origin - Attachment of muscle to stationary bone
Insertion - Attachment of muscle to moving bone
- What is extension and flexion?
- Extension - Straightening of a joint
Flexion - Bending of a joint
- What is skeletal muscle?
Multinucleated fiber cells
Within each fiber are filaments called myofibrils, further divided into contractile units called sarcomeres
- What is the sarcoplasmic reticulum?
- Modified endoplasmic reticulum that stores calcium ions
- What is the cytoplasm of a muscle cell called?
- What is the cell membrance called in a muscle cell?
- What is capable of propagating a signal in a muscle cell?
- sarcolemma, connected to system of transverse tubules (T system) oriented perpendicular to myofibrils
- What is the T system?
- Transverse tubules
Provides channels for ion flow throughout the muscle fibers, and can also propagate an action potential
- Why are mitochondria very abundant in muscle cells?
- Muscle cells require substantial amounts of energy to perform well
- What type of filaments are sarcomeres composed of?
- Thick and Thin filaments
- What type of molecules are thin and thick filaments?
- Thin - actin molecules
Thick - myosin
- What are Z-lines?
- Define boundaries of a single sarcomere and anchor thin filaments
- What is the M line?
- Runs down center of sarcomere?
- What is the I Band?
- Region containing thin filaments only
- What is the H zone?
- Region containing thick filaments only
- What is the A band?
- Spans the entire length of the thick filaments and any overlapping portions of the thin filaments
- During contraction, which segments are reduced in size?
- H zone and I band are reduced
A band is not reduced in size
- What is the link between the nerve terminal and sarcolemma called?
- Neuromuscular Junction
- Once an action potential reaches the muscle fiber, how is it propagated within the fiber?
- Along sarcolemma and the T system, and into interior of the muscle system
Causes sarcoplasmic reticulum to release calcium ions into the sarcoplasm
Calcium ions initiate the contraction of the sarcomere
Actin and myosin slide past each other and the sarcomere contracts
- How is the strength of the entire muscle contraction increased?
- By recruiting more muscle fibers
- What is a simple twitch?
- Response of a single muscle fiber to a brief stimulus at above threshold stimulus
Consists of latent period, contraction period, relaxation period
- What is the latent period?
- Time between stimulation and onset of contraction
Action potential is spread throughout sarcolemma and Ca2+ ions are released
- What is the contraction period?
- Period in which fibers contract
- What is relaxation period?
- Muscle is unresponsive to stimulus
AKA absolute refractory period
- What is summation?
- When fibers are exposed to very frequent stimuli, muscle can not fully relax
Contraction begin to combine, become stronger and more prolonged
- What is tetanus?
- Contractions become so frequent muscle can not relax
If tetanus is maintained, muscle will fatigue and contraction will weaken
- What is tonus?
- State of partial contraction
Muscles are never completely relaxed and maintain a partially contracted state at all times
- What are the basics of smooth muscle?
- Involuntary actions and innervated by autonomic nervous system
One centrally located nucleus
- What are the basics of cardiac muscle?
- Striated appearance
Only one or two centrally located nuclei
- What are two energy reserves when ATP is depleted?
- Creatine Phosphate (vertebrates) and Arginine Phosphate (invertebrates)
Temporary storage of high energy compound
- What is myoglobin?
- Hemoglobin like protein found in muscle tissue
Very high affinity for oxygen
- What is myogenic?
- Not sure
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