Muscles, Locomotion & Animal Energetics Flashcards
Kinesins
Move along MTs towards + end
Dyneins
Move towards MTs toward - end
Axoneme
MT arrangement in cilia and flagella; 9 + 2
Microfilaments
Long polymers of actin proteins
Motor proteins
Mechanoproteins that use ATP as energy
Sarcomere
1 unit of a myofibril, the area in between Z-disks
Conscious control muscles
Neurogenic muscles
Unconscious control muscles
Myogenic muscles
Tropomyosin
Double-stranded proteins that cover myosin binding sites on actin
Troponin
3 subunit protein that is located on the 7th actin monomer; will shift when calcium is present
Where do motor neurons originate and innervate?
Ventral horn and muscle fibers
What is the neurotransmitter at the NMJ?
Acetylcholine (always excitatory)
Where does the motor neuron synapse on the myofiber?
Motor end plates
T-tubules
Invaginations of the sarcolemma that allow the AP to enter into the myofiber
Sarcoplasmic reticulum
Wrap each myofibril and receive electrical impulses and store calcium
How is calcium released in skeletal muscles?
Change of DHPR structure on plasma membrane, trigger the opening of RyR
How is calcium released in cardiac muscles?
Increased calcium [] that enters cells from DHPR
What happens to the muscle fiber when tropomyosin blocks the myosin-binding sites?
Muscle fiber relaxation
Motor unit
A motor neuron and the muscles it innervates
2 main muscle fiber types
Fast and slow twitch
Characteristics of fast twitch muscle fibers
Glycolytic, white in colour (no myoglobin) and type II
Characteristics of slow twitch muscle fibers
Oxidative, red in colour (myoglobin) and type I
Sonic muscles
Vibration of muscles produces high-frequency contractions
Synchronous vs asynchronous flight muscles
There is a correlation between AP and contraction, but not in asynchronous (there are multiple contractions per AP, doesn’t have to do with calcium release)