Autonomic Physiology Flashcards
Give one similarity between the autonomic and somatic nervous systems.
Both involved in efferent nervous system.
Give 6 differences between the autonomic and somatic nervous systems.
- Autonomic nervous system is involuntary. Somatic is voluntary.
- Autonomic nervous system involves metabotropic receptors. Somatic involves ionotropic.
- Autonomic nervous system involves pre and post synaptic fibres. Somatic involves one long, uninterrupted system.
- Autonomic system innervates smooth muscle, cardiac muscle, glands and GI neurons. Somatic system innervates smooth muscle.
- Autonomic system is less specialised. Whereas, the somatic system involves the specialised NMJ.
- Autonomic nervous system can be excitatory or inhibitory. Somatic nervous system is always excitatory.
Into what two systems is the autonomic nervous system divided?
Parasympathetic and sympathetic systems.
What body regions facilitate the outflow of parasympathetic fibres?
Cranial and Sacral
What body regions facilitate the outflow of sympathetic fibres?
Thoracic and Lumbar
What is the difference in ganglia position between the sympathetic and parasympathetic systems?
In the sympathetic system, ganglia lie close to the spinal cord.
In the parasympathetic system, ganglia lie close to or within the target tissue.
What type of receptors does acetylcholine act on?
Cholinergic
Muscarinic and Nicotinic
What type of receptors does adrenaline/noradrenaline act on?
Adrenergic
Alpha and Beta receptors
Describe the neurotransmitters involved in the sympathetic nervous system.
Preganglionic fibres release Acetylcholine which acts on nicotinic receptors.
Post ganglionic fibres release Adrenaline/Noradrenaline which acts on alpha/ Beta receptors.
Describe the neurotransmitters involved in the parasympathetic nervous system.
Preganglionic fibres release Acetylcholine which acts on nicotinic receptors.
Postganglionic fibres release Acetylcholine which acts on muscarinic receptors.
How are sweat glands innervated?
By postsynaptic sympathetic fibres which release acetylcholine.
(This is an exception)
Describe the effect of the sympathetic system on the control of the eye.
- Activates B2 receptors on the ciliary muscles around the lens to cause relaxation and focus on far away objects
- Activates alpha1 receptors on radial muscle of iris to cause it to contract and increase pupil diameter.
Describe the effect of the para-sympathetic system on the control of the eye.
- Activates muscarinic receptors on the ciliary muscles around the lens to cause relaxation and focusing on close up objects
- Activates muscarinic receptors on radial muscles of the iris to cause it to relax and decrease pupil diameter.
Describe the effect of the sympathetic system on the control of the heart.
- Activation of B1 receptors on pacemaker cells to increase heart rate.
- Activation of B1 receptors on myocytes to increase strength of contraction
Describe the effect of the parasympathetic system on the control of the heart
-Activation of muscarinic receptors on pacemaker cells to decrease heart rate.
Describe the effect of the sympathetic system on the control of the lungs.
-Activation of B2 receptors on smooth muscle of airways to relax and dilate vessel
Describe the effect of the parasympathetic system on the control of the lungs.
-Activation of muscarinic receptors on smooth muscle of airways to contract and constrict.
Describe the effect of the sympathetic system on the control of the gut.
- Activation of alpha/beta receptors on smooth muscle of gut to decrease gut motility
- Activation of alpha receptors on pancreas to decrease enzyme secretion
Describe the effect of the parasympathetic system on the control of the gut.
- Activation of muscarinic receptors on the smooth muscle of the gut wall to increase gut motility.
- Activation of muscarinic receptors on pancreas to increase enzyme secretion
Describe the effect of the sympathetic system on the control of the blood vessels.
- Activation of alpha one receptors on the blood vessel walls to cause contraction and restrict blood flow.
- Activation of B2 receptors on the blood vessel walls to cause relaxation and allow increased blood flow.
Describe the effect of the sympathetic system on the control of the energy stores.
- Activation of alpha/ beta receptors on the liver to stimulate increased glyconeolysis/gluconeogenesis
- Activation of alpha/beta receptors on fat cells to stimulate lipolysis
Describe the effect of the sympathetic system on the control of the salivary glands.
-Activation of B receptors to stimulate release of thick enzyme rich secretion
Describe the effect of the parasympathetic system on the control of the salivary glands.
-Activation of muscarinic receptors to stimulate release of watery secretion.
Describe the effect of the sympathetic system on the control of the bladder.
- Activation of B2 receptors on the smooth muscle of the bladder wall to allow relaxation and decrease in pressure.
- Activation of Alpha1 receptors on the smooth muscle of the sphincter to stimulate contraction to prevent urination.
Describe the effect of the parasympathetic system on the control of the bladder.
- Activation of muscarinic receptors on smooth muscle of bladder wall to generate contraction and so increase in pressure.
- Activation of muscarinic receptors on smooth muscle of sphincter to generate relaxation and allow for urination.
Describe the effect of the sympathetic system on the control of the reproductive tract.
-Activation of alpha 1 receptors on the smooth muscle of the urethra, causing it to contract and cause ejaculation.
Describe the effect of the parasympathetic system on the control of the reproductive tract.
-Activation of muscarinic receptors on the smooth muscle of the corpus cavernosum to relax it and allow erection.
What is the role of the baroreceptor reflex?
To detect blood pressure
What controls the autonomic nervous system actions?
- Central control via the hypothalamus (co-ordinating autonomic, somatic and endocrine actions)
- Reflexes, such as the baroreceptor reflex
