Block B Flashcards
What makes up the peripheral nervous system?
Sensory
Autonomic- Glands + Cardiac muscle
somatic- Skeletal muscle
Outline the peripheral nervous system
Makes up the cranial and spinal nerves. Facilitates communication between the CNS and the body.
Outline the difference between afferent and efferent nerves.
Afferent nerves- Conduct impulse from receptors to CNS
Efferent nerves- Conduct impulse form the CNS to effectors (muscles, glands..)
Outline the Somatic nervous system.
Activates somatic (voluntary) motor nerves. Works with skeletal muscle.
Outline the Autonomic nervous system.
Activates visceral (involuntary) motor nerves. Activates cardiac/smooth muscle and glands.
What are the two components of the autonomic nervous system?
Sympathetic division- Mobilises body for activity (fight or flight)
Parasympathetic division- Conserves energy, promotes digestion (rest and repair)
Outline the differences and similarities between the sympathetic and parasympathetic nervous systems for
1)Ganglia neurotransmitters
2)Location of Ganglia
3)Effector neurotransmitters
1)sympathetic-ACh acting on nicotinic ACh receptors
parasympathetic-ACh acting on nicotinic receptors
2)sympathetic-Close to spinal cord
Parasympathetic- Close to/ within organs
3)Sympathetic-Noradrenaline acting on adrenoceptors
ACh acting on muscarinic ACh receptors
Parasympathetic-ACh acting on muscarinic ACh receptors
What is the neurotransmitter used on all autonomic ganglia?
Acetylcholine
What is the neurotransmitter used at all parasympathetic neuroeffector junctions?
Acetylcholine
What neurotransmitter is used at most sympathetic neuroeffector junctions?
Noradrenaline
What is the process for the conversion of tyrosine to noradrenaline and adrenaline?
Tyrosine converts to DOPA via tyrosine hydroxylase
DOPA converts to Dopamine via DOPA decarboxylase
Dopamine converts to Noradrenaline via Dopamine b-hydroxylase (synthesis stops here at sympathetic nerve endings)
Noradrenaline converts to Adrenaline via phenylethanolamine n-methyl transferase
(adrenal medulla only)
What occurs in the uptake step for inactivation of catecholamines?
Neuronal: Into nerve endings. Fairly specific for noradrenaline- rapid and efficient major route. 90% of released noradrenaline
Extra-Neuronal: Into other cells and tissues. Less specific. Adrenaline removed faster than NA. Important at synapse only when neuronal uptake impaired.
What occurs in the Enzymatic inactivation step of the inactivation of catecholamines?
Monoamine oxidase (MOA): In the nerve ending- associated with mitochondria, also in extracellular fluid
Catechol-o-methyl transferase (COMT):
In extracellular fluid.
What is the final step of the inactivation of catecholamines?
Diffusion
What are the functions of the parasympathetic nervous system
Non-stressful conditions
Times of rest and repair
Slows heartbeat and promotes digestion and gland secretion
