A&P 2.13 neurotransmitters Flashcards
Deep six lateral/external rotators of the hip in order they attach to femur superior to inferior and lateral to medial as they attach to the trochanter
Piriformis Gamellus superior Obturator internus Gemellus inferior Obturator externus Quadratus femorus
PGOGOQ
Piriformis
A, I, O
A- lateral rotation of the femur and extension of the hip; abduction, horizontal abduction, and medial rotation of the FLEXED HIP
I - distal attachment - upper border of the greater trochanter (superior aspect)
O - proximal attachment - anterior surface of the sacrum
Pear shaped
Gamellus superior
A, I, O
A - lateral rotation of the femur/hip (extension)
I - distal attachment - medial surface of the greater trochanter
O - proximal attachment -ischial spine (dorsal surface)
Gemellus inferior
A, I, O
A - lateral rotation of the femur/hip (extension)
I - distal attachment - medial surface of greater trochanter
O - proximal attachment - ischial tuberosity
Synapse
Defined
The place where signals are transmitted from one neuron (presynaptic neuron) to another neuron (postsynaptic neuron) or a postsynaptic cell such as a muscle fiber or gland
Two types of synapses
Electrical
Chemical
Electric synapse found
Between cardiac muscle cells and some smooth muscle cells
Chemical synapse
General
Most common type of synapse in the body
Uses chemicals called neurotransmitters to send a signal from the presynaptic cell to the post synaptic cell
PRIMARILY ACYTLECHOLINE
Three structures make up a chemical synapse
Synaptic knob (presynaptic)
Synaptic cleft
Plasma membrane of a postsynaptic cell
Nerve cell = neuron
.
Neurotransmitter
Defined
Chemicals by which neurons communicate
They are the means by which neurons talk to one another
Neurotransmitter
How they work
They are released by a Neuron, diffuse across the synapse, and bind to a postsynaptic cell (usually another neuron)
Neurotransmitters act to
Facilitate/stimulate
Or
Inhibit action potentials at synapses throughout the body
Neurotransmitters classified by
Function
Chemical structure
Neurotransmitters
Classified by function
2
Excitatory
Inhibitory
Excitatority
Causes depolarization (signal continues)
Inhibitory
Causes hyperpolarization (slows down or stops signal)
Neurotransmitters
5
Acetylcholine Dopamine Epinephrine Norepinephrine Endorphins
Acetylcholine
Excitatory (skeletal muscle) or
inhibitory (cardiac muscle),
located in junctions with motor effectors (muscles, glands), and many parts of the brain also involved in memory
Dopamine
Mostly inhibitory, involved in emotions/moods and in regulating motor control - located in the brain and the autonomic nervous system
PARKINSON’S
Epinephrine/norepinephrine
Both are excitatory and inhibitory
E acts as a hormone when secreted by sympathetic neurosecretory cells of the adrenal gland
N regulates sympathetic effectors, in brain, involved emotional response. Also known as adrelinine FIGHT OR FLIGHT RESPONSE
Endorphins
Mostly inhibitory, acts like opiates to block pain, located in several regions of the CNS, retina, and intestinal tract
Neuromuscular junction
Defined
A type of connection between a motor neuron fiber and a muscle cell (chemical synapse)
Neuromuscular junction
How it works
Nerve impulse reaches the end of a motor neuron fiber and small vesicles release acetylcholine into the synaptic cleft
Acetylcholine diffuses across to the sarcolemma of the adjacent muscle fiber and finds receptor sites
When the receptor sites are filled they initiate an electrical impulse in the sarcolemma
Impulse ultimately causes contraction of the muscle fiber
