BIO 360 - Exam 3 - Chapter 12 Summary Questions Flashcards
______ generate motion, force, and heat.
Muscles
The three types of muscle are:
skeletal muscle, cardiac muscle, and smooth muscle. Skeletal and cardiac muscles are striated muscles.
Skeletal muscles are controlled by ______ ______ neurons. Cardiac and smooth muscle are controlled by a_____ i______, p______ s______, and h______.
Some smooth and cardiac muscles are ______ and contract spontaneously.
somatic motor / autonomic innervation, paracrine signals, and hormones / auto-rhythmic
Skeletal muscles are usually attached to bones by tendons. The ______ is the end of the muscle attached closest to the trunk or to the more stationary bone. The ______ is the more distal or mobile attachment.
origin / insertion
At a flexible joint, muscle contraction moves the skeleton. ______ bring bones closer together; ______ move bones away from each other. Flexor-extensor pairs are examples of ______ muscle groups.
Flexors / extensors / antagonistic
A skeletal muscle is a collection of ______ ______, large cells with many nuclei.
muscle fibers
______ allow action potentials to move rapidly into the interior of the fiber and release calcium from the s______ r______.
T-tubules / sarcoplasmic reticulum
______ are intracellular bundles of contractile and elastic proteins. ______ filaments are made of ______. ______ filaments are made mostly of ______. _____ and ______ hold thick and thin filaments in position.
Myofibrils / Thick filaments / myosin / Thin filaments / actin / Titan / nebulin
Myosin binds to actin, creating ______ between the thick and thin filaments.
crossbridges
A ______ is the contractile unit of a myofibril. It is composed of two ______ and the filaments between them. The sarcomere is divided into ______ (thin filaments only), an ______ that runs the length of a thick filament, and a central ______ occupied by thick filaments only. The ______ and Z disks represent attachment sites for myosin and actin, respectively.
sarcomere / Z disks / I bands / A band / H zone / M line
The force created by a contracting muscle is called ______ ______. The ______ is a weight or force that opposes contraction of a muscle.
muscle tension / load
The _________________________________ states that during contraction, overlapping thick and thin filaments slide past each other in an energy-dependent manner as a result of actin-myosin crossbridge movement.
sliding filament theory of contraction
In relaxed muscle, ______ partially blocks the myosin-binding site on actin. To initiate contraction, ______ binds to ______. This unblocks the myosin-binding sites and allows myosin to complete its power stroke.
tropomyosin / Ca2+ / troponin
During relaxation, the sarcoplasmic reticulum uses a ________
to pump _______ back into its lumen.
Ca2+ - ATPase / Ca2+
Myosin converts energy from ATP into motion. ______ ______ hydrolyzes ATP to ADP and ______.
Myosin ATPase / Pi
When myosin releases ______ the myosin head moves in the ______ ______. At the end of the power stroke, myosin releases ADP. The cycle ends in the ______ ______, with myosin tightly bound to actin.
Pi / power stroke / rigor state
In ______ - ______ ______, a somatic motor neuron releases ACh, which initiates a skeletal muscle action potential that leads to contraction.
excitation-contraction coupling