Ch. 15.6- Comparison of Neurotransmitters Flashcards
What are cholinergic neurotransmitters?
Neurons the make and release ACh.
Cholinergic receptors
Receptors the bind ACh.
There are only two types of theses. They are nicotinic and muscarinic.
Which are cholinergic neurons?
All sympathetic and parasympathetic preganglionic neurons.
All parasympathetic preganglionic neurons.
Sympathetic ganglionic neurons that innervate sweat glands of the skin.
Adrenergic Neurons
Neurons that make and secrete norepinephrine.
Adrenergic Receptors
Neurons that bind norepinephrine or epinephrine.
These are decided into alpha and beta types.
Nicotinic receptors
Found on the cell bodies and dendrites of all ganglionic neurons and on adrenal medulla cells.
What happened when nicotinic receptors are stimulated?
Na+ enters the the cell and K+ leaves the cell.
Muscarinic Receptor locations
All target organs associated with the parasympathetic nervous system and a few sympathetic (sweat glands of skin and blood vessels in skeletal muscle) target cells.
What kind of message system do muscarinic receptors use?
Second messenger systems.
Ligands
Signaling molecules (hormones and neurotransmitters) that specifically bind to receptors in the plasma membrane.
Biogenic amines
Also called monoamines
Ligands that bind to adrenergic receptors in neurons.
Catecholamines
Category of biogenic amines.
These induce dopamine, epinephrine, and norepinephrine
What types of adrenergic receptors are there?
Alpha 1, Alpha 2, Beta 1, Beta 2, Beta 3
What are alpha 1 receptors responsible for?
Most common adrenergic receptor of the sympathetic division of the autonomic nervous system.
Found in the plasma membranes of most smooth muscles cells.
They stimulate smooth muscle contraction.
Organs stimulated: Blood vessels of skin, GI, and kidneys, arrector pili muscles, uterus, ureters, internal urethra sphincter, and dilatory pupillae muscles of the eye.
This means dilation of blood vessels, and contraction of other muscles.
What are alpha 2 receptors responsible for?
Located throughout the CNS and decrease norepinephrine release.
Also in the pancreases to inhibit insulin secretion.
Also found in the GI sphincter which causes the sphincter to close.
Stimulation of these causes sedation and analgesia.
Beta 1 adrenergic receptors
Primarily stimulatory effects.
Found in the heart where they increase heart rate and force of contraction.
Found in kidneys where they stimulate secretion of renin-which causes an increase in blood pressure.
Beta 2 adrenergic receptors
Primarily inhibitory effects.
Present in coronary arteries and smooth muscle vessels of the liver.
Stimulation of these causes smooth muscle relaxation.
This also causes bronchodilation and relaxation of uterine tract and GI smooth muscle.
Beta 3 adrenergic receptors
Excitatory of inhibitory.
Found in adipose connective tissue where they stimulate lipolyisis (break down of triglycerides into fuel molecules)
Also cause smooth muscle relaxation in urinary bladder.
