2.5 -- Intro to Muscles Flashcards
What are the three types of muscles?
Smooth, cardiac, and skeletal
What is a key target of neurons?
Muscles
The functional classification of neurons is based on what?
Direction impulses are conducted
What are the two types of neurons?
Sensory and motor neurons
What is a sensory neuron?
Conducts impulses from the sensory receptors to the CNS
What is a motor neuron?
Conducts impulses from the CNS to target organs (Glands or muscles)
What does sarco mean?
Of the muscle
What is the muscle cell equivalent of the term muscle cell?
Muscle fiber (Myofiber)
What is the muscle cell equivalent of the term cell membrane?
Sarcolemma
What is the muscle cell equivalent of the term cytoplasm?
Sarcoplasm
What is the muscle cell equivalent of the term modified endoplasmic reticulum?
Sarcoplasmic reticulum
What are two characteristics of skeletal muscle?
Striated and voluntary
What has fibers that are large, multinucleate cells that appear striated under the microscope?
Skeletal muscle
What are the two characteristics of cardiac muscle?
Striated and involuntary
What has fibers that are striated but smaller, uninucleate, and branched and has cells that are joined by intercalated disks?
Cardiac muscle
What are the two characteristics of smooth muscle?
Smooth and voluntary
What has fibers that are small and lack striations?
Smooth muscle
A skeletal muscle is made up of many what, which is a bundle of what?
Fascicle, myofibers
What is a single cell, containing multiple bundles of contractile elements?
Myofiber
What stores calcium in a muscle cell?
Sarcoplasmic reticulum
What are the four parts of a myofiber?
Myofibril, mitochondria, sarcoplasmic reticulum, and t-tubules
What are the nine steps of connecting an action potential to a muscle contraction in order?
Action potential produced
ACh released
Ca 2+ binds to troponin, stimulating contraction
Ca 2+ diffuses out into sarcoplasm
Action potential opens voltage-gated Ca 2+ channels
Na+ diffuses in, producing depolarizing stimulus
Binds to nicotinic ACh receptors, opens ligand-gated channels
Action potentials conducted along transverse tubules
Ca 2+ release channels in sarcoplasmic reticulum open
1). ACh released
2). Binds to nicotinic ACh receptors, opens ligand-gated channels
3). Na+ diffuses in, producing depolarizing stimulus
4). Action potential produced
5). Action potentials conducted along transverse tubules
6). Action potential opens voltage-gated Ca 2+ channels
7). Ca 2+ release channels in sarcoplasmic reticulum open
8). Ca 2+ diffuses out into sarcoplasm
9). Ca 2+ binds to troponin, stimulating contraction
What are t-tubules?
Extensions of sarcolemma that associated with the ends of sarcoplasmic reticulum
What do t-tubules do?
Bring action potential into the interior of muscle fiber
