physiology exam 2.docx - Chap 13 Synapses-A synapse is the...

Chap 13 Synapses:
-A synapse is the place where two neurons meet, which includes a small gap between the axon
terminals of pre-synaptic membrane and the dendrites of the post-synaptic membrane (i.e. the
synaptic cleft) and the post-synaptic membrane.
-Electrical transmission: the cytoplasm of two neurons is connected via gap junctions , allowing
the ions of the action potential to conduct directly into the effector neuron. (faster, Bidirectional,
excitory)
-Chemical transmission: signals are sent between neurons via chemicals, called
neurotransmitters , that bind to receptors on the post-synaptic membrane. (unidirectional,
excitatory or inhibitory, plastic)
-iClicker: Which is true of electrical synapses? A.They only respond to excitatory
neurotransmitters.
Chap 20 Muscle Contractions:
Muscle is a tissue built of specialized contractile cells. There are two main categories of muscle:
1) Striated muscle tissue has the appearance of alternating light and dark bands, which are
collections of contractile proteins called sarcomeres . In vertebrates, the striated muscle makes
up the skeletal (most) and cardiac muscle .
2)Smooth muscle tissue also uses contractile proteins, but they are not organized into
sarcomeres, so it doesn’t have a striated appearance. In vertebrates, smooth muscle lines the
blood vessels, gut, respiratory tract, etc.
- Skeletal Muscles are Organized Hierarchically
Skeletal muscle consists of multiple bundles of muscle fibers
Myofibers are long, multinucleate, cylindrical cells, organized in parallel
Each myofiber consists of many parallel myofibrils
Each myofibril is composed of repeated sarcomeres
The sarcomere is the fundemental unit of contraction, which consists of actin and myosin
filaments
Skeletal muscle consists of multiplebundles of muscle fibers
Myofibers are long, multinucleate, cylindrical cells, organized in parallel
The sarcomere is the fundemental unit of contraction, which consists of actin and myosin
filaments
- Skeletal muscle fibers are subdivided into repeated 2 μm long striated sarcomeres with a z disk
at each end.