Chapter 7 Flashcards
Why do we have a brain
to control our behavior. If we were stationary like a plant, we would not need a brain (like a plant)
three types of muscles
smooth muscles: for organs
skeletal or striated muscles: control of body movement
cardiac muscles: control the heart
muscle fiber - axon ratio
one muscle fiber can only have one axon, but one axon can control many fibers
synapse between motor neuron and muscle fiber. For all skeletal muscles acetylcholine is the neurotransmitter. It excites the muscle to contract
each muscle can only make one movement: contraction. relaxation is a lack of contraction. to move a limb in more than one direction requires antagonistic muscles, which work in opposite directions. The flexor for example brings your hand towards your shoulder, while the extensor straightens the arm.
fast twitch and slow twitch fibers
fast twitch: fast contraction but also rapid fatigue
slow twitch: slower contraction but no fatigue
slow twitch fibers are aerobic because they continually use oxygen.
fast twitch fibers are anaerobic because they don’t need oxygen to function, but need it to recover from functioning (oxygen debt)
receptor that detects the position of movement of a part of the body
reflex caused by stretching of a muscle. It contracts back to its original position
Is a kind of proprioceptor.
Whenever the muscle spindle is stretched, its sensory nerve sends a message to a motor neuron in the spinal cord, which in turn sends a message back to the muscles surrounding the spindle, causing a contraction.
Golgi tendon organs
also proprioceptors, respond to increases in muscle tension. Located at opposite ends of a muscle.
In short, a vigorous muscle contraction inhibits further contraction by activating the Golgi tendon organs
Reflexes are consistent automatic responses to stimuli
ballistic movement, such as a reflex, is executed as a whole: Once initiated, it cannot be altered. However, most behaviors are subject to feedback correction
central pattern generators
neural mechanisms in the spinal cord that generate rhythmic patterns of motor output.
behavioral sequence that once begun, is fixed from beginning to end
primary motor cortex
we know it already but again: anterior gyrus just anterior to the central sulcus. We can map our body on it, and it matches up nice with the sensory cortex, right on the other side of the central sulcus