Physiology Lecture Notes - Nervous System Recap

Lecture 4 -Autonomic Nervous System

Nervous system recap

• Central
• Peripheral

• Somatic

• Has one neuron

• Autonomic

• Has two neurons
• Sympathetic – fight or flight, for survival

• Neurotransmitter released at ganglion

• Acetyl choline released pre and post ganglionic neuron
• norepinepherine

• Parasympathetic – active when calm, preserves energy

• Neurotransmitter

• Acetyl choline released pre and post ganglionic neuron
• Acetyle choline also released…
• Receptors

• Ionotropic- coupled to ion channel

• Example is acetyl choline acting on nicotinic receptors on post ganglionic neurons

• Metabotropic- coupled to g proteins, change in cellular function of protein

• Neurotransmitter within ganglia
• Neuron to effector transmission

• Muscarinic receptors

• Differences between sympathetic and para

• Sympathetic pre ganglionic is long, other is shorter
• Parasympathetic nerves originate from spinal cord
• Both opposites

Terminology

• Ganglion
• Synapse
• Neurotransmitter
• Afferent and efferent nerves

• Afferent towards CNS
• Efferent away from CNS

Adrenal Gland

• There is only one neuron innovating adrenal gland
• Pre ganglionic innovates adrenal gland located top of kidneys
• When activated

• Adrenal Medulla releases hormones into blood stream

• [pic 1]
• Inner most part of adrenal gland, composoed of chromaffin cells- secrete adrenaline and epinephrine and also non adrenaline and non epinephrine
• [pic 2]
• In the adrenal meduall there is no post ganglionic neuron instead hormones
• Once released adrenaline acts on alpha and beta receptors
• Effects of adrenaline on heart

• On beta
• Increases blood flow to heart musle
• Heart has electrical system which is coupled to contraction so once u increased rate it increases cardio contractility

• This needs more blood supply

• Cellular level

• Increases contraction in  heart decreases in coronary artery

• Adrenaline acting on beta 1 and 2
• Indudces calcium release from cytoplasmic reticulum

• Blood vessel

• Adrenaline acting on beta 2 receptors thru cyclic