Neurotransmission ANS Flashcards
What is the definition of neurotransmission?
Communication process where neurotransmitters are released by a (presynaptic)!neuron and bind to and activate the receptors of another cell
What kind of synapse does the neurotransmitter belong to?
Chemical synapses
What are three kinds of neurotransmitters?
Acetylcholine (ACh)
Norepinephrine (NE or NA)
Epinephrine (EPI or A)
What are the two types of neurons releasing NT?
Cholinergic-releases ACh
Adrenergic- releases NE
What are the characteristics of ACh?
Different functions in the Braun and peripheral NS incl both branches of ANS
the neurotransmitter of the neuromuscular junction
What are the characteristics of NE?
Synthesized and released by CNS and Sympatethic NS
Fight or flight
What are the main differences between somatic NS and Autonomic NS?
Somatic is voluntary, all receptors are cholinergic, skeletal muscle
ANS is involuntary, both cholinergic and adrenergic
Consists of two neurons, (pre/post), cholinergic and adrenergic, innervates cardiac, smooth and glandular epithelium, can also inhibit organ functions
What nerves belongs to Parasympatethic NS?
Cranial nerves and sacral nerves
What nerves belong to the sympatetic NS?
Thoracic nerves, lumbar nerves
What does the thoracis postganglionic neurons control?
Organs of the skull, chest, abdomen and forelegs
What does lumbar postganglionic neurons innervate?
Organs of the pelcic cavity and hind limbs
What are the functions of sympatetic NS?
Excitatory (contraction) of smooth muscles as vessels, hair, instestinal sphinxers and dilate pupils
Fight or flight response
What are the functions of parasympatethic NS?
Very long reganglionic fibers, controls respiratory, heart, esophagus, stomach, small intestins and other GI organs
Rest and digest response
What does antagonistic functions mean?
That the work in opposite ways.
The parasymp. Slows heartbeat while the symp increases it and so on
What are the characteristics of preganglionic neurons?
Myelinated, all cholinergic
What are the characteristics of postganglionic neurons in parasymp NS?
Unmyelinated, all cholinergic
What are the characteristics of postganglionic neurons in symp NS?
Unmyelinated, all adrenergic (except sweatglands, pilorector muscles, some blood vessels in skeletal muscle)
What are the two types of cholinergic receptors?
Nikotinic and muscarinic
What are the two types of adrenergic receptors?
Alpha and beta
Where are nicotinic receptors found?
Neuro muscular junction (NMJ) and brain
Where is muscarinic receptors found?
CNS, heart, smooth muscle
What are the alpha receptors effects?
Contraction of vascular smooth muscle
What are the beta effects?
Relaxation of vascular smooth muscle, increase rate and force of cardiac contraction
What effects (alpha/beta) does Epinephrine have?
All alpha and beta, 10 times more effektive on beta2 receptors than NE
What effects (alpha/beta) does norepinephrine have?
Alpha effects mainly, but also beta1
What are the function of alpha-receptors?
Vasoconstriction Iris dilation Intestinal relaxation Intestinal sphincter contraction Pilomotor contraction Bladder sphincter contraction USUALLY EXCITATORY
What are the function of beta- receptors?
Vasodilation Cardioacceleration Increased myocardial strenght Intestinal relaxation Uterus relaxation Bronchodilation Calorigenesis Glycigenolysis Lipolysis Bladder Wall relaxation
What is the concequence/effect of release of ACh by parasymp postganglionic neurons?
Recieved by muscarinic ACh receptors-decreased heartrate and vonduction velocity
What is the concequence/effect of release of NE by symp. postganglionic neurons?
Recieved by Beta1 adrenoreceptors
Increased heartrate, contractility, conduction velocity
