Autonomic pharmacology 1 Flashcards
What are the two branches of the Nervous system?
Central nervous system
Peripheral nervous system
What are the branches of the peripheral nervous system? (4)
- Somatic efferent
- Enteric nervous system
- Autonomic nervous system
- Somatic and visceral afferent
What are the two divisions of the Autonomic nervous system?
Sympathetic
Parasympathetic
What is the function of the ANS?
- To carry output from the CNS to the whole of the body, except the skeletal muscles.
- To regulate visceral (internal organs/cavities) functions that are involuntary.
Give some examples of functions of the ANS. (4)
- Contraction and relaxation of vascular and visceral smooth muscle
- All exocrine and some endocrine sections
- The heartbeat
- Aspects of metabolic (Particularly liver and skeletal muscle)
What does the term somatic mean?
It refers to fibres that innovate sensory fibres such as skin muscles.
Describe the somatic efferent branch of the PNS.
It carries signals from the CNS to the skeletal muscles.
What is a ganglion?
A collection of nerve cell bodies that lie outside the CNS.
What is the function of ganglia?
They provide relay point and intermediary connections between different neurological structures in the body, such as the PNS and CNS
What functions does the sympathetic ANS serve?
- Coordinates body’s response to stress
- Associated with fight, flight or fright reactions.
What function does the parasympathetic ANS serve?
Coordinates the body’s basic homeostatic functions.
Which neurotransmitter is always present in the preganglionic neurones of the sympathetic and parasympathetic ANS?
Acetylcholine (ACh)
Which cranial nerves have a parasympathetic outflow? What is there collective name?
Nerves III, VII, IX and X
collectively the vagus nerves
What effects does the Sympathetic ANS have on the heart? (2)
- Increase heart rate
- Increase force of contraction
What effects does the Sympathetic ANS have on the lungs? (2)
- Relaxes bronchi (Via release of adrenaline)
- Decreases mucous production (Which decreases airway resistance)
What effects does the Sympathetic ANS have on the intestines? (2)
- Reduces motility
- Constricts sphincters
What effects does the Sympathetic ANS have on the adrenal gland?
Cause adrenaline release.
What effects does the parasympathetic ANS have on the heart?
Decreases heart rate
What effects does the parasympathetic ANS have on the lungs? (2)
- Constrict bronchi
- Stimulates mucous production (Increases airway resistance)
What effects does the parasympathetic ANS have on the intestines? (2)
- Increases motility
- Relaxes sphincters
What effects does the parasympathetic ANS have on the adrenal gland?
No effect
What effects does the parasympathetic ANS have on the penis?
Causes erection
What effects does the sympathetic ANS have on the penis?
Causes ejaculation
What triggers the release of Acetylcholine in the sympathetic division?
-An action potential triggers Ca2+ to enter the preganglionic neurone and release ACh.
What are the differences between neurotransmitter release in the parasympathetic division than the sympathetic division?
- ACh is always the transmitter used by postganglionic neurones in the parasympathetic division
- ACh activates G protein-coupled muscarinic acetylcholine receptors in the target cell membrane causing a response in the parasympathetic division.
What is a disadvantage of G-protein receptors compared to transmitter-gated ion channels?
Signalling is relatively slow by G protein receptors.
What is an example of a G-protein coupled receptor?
A muscarinic ACh receptor
Describe the structure of a G-protein couple receptor.
- Integral membrane protein
- Single polypeptide with extracellular Nh2 and intracellular COOH termini
- Contains 7 transmembrane spans joined by three extracellular and three intracellular connecting loops.
