Autonomic nervous system Flashcards
Understand the anatomical organisation of the ANS including the arrangement of the main nerve cells which form the PS and S systems\ Describe the main functions of the PS and S NS Describe the main chemical neurotransmitters of the ANS and be aware of their receptors
What does autonomous mean?
Self governing
What is the visceral nervous system?
Part of the ANS and has control over internal organs
What is the hierarchy of the nervous systems?
- Central Nervous system
- Peripheral nervous system
- Somatic and Autonomic
- (Autonomic) - Parasympathetic, sympathetic and enteric
What does afferent mean?
Carries instructions TO the CNS
What does efferent mean?
Carries instructions FROM the CNS
What does somatic mean?
Under our conscious control - skeletal muscles
What does autonomic mean?
Unconscious control of cardiac, smooth muscle and glands
Where is the para/sympathetic division located?
Based on the CNS location of the cell body on the preganglionic nerve
Where is the enteric system located?
The gut
What do axons of the SOMATIC nervous system have?
A single myelinated axon extending from the CNS to the effector
Where is the cell body located for skeletal muscle?
Spinal cord
What do axons of the AUTONOMIC NS have?
A 2 neuron chain - pre ganglionic (extends to ganglion) and post ganglionic neuron (extends from ganglion to effector)
What is a ganglia?
Cell bodies of many peripheral autonomic neurones occur in clusters and and form swellings on nerve trunks
Name 2 EFFERENT pathways of there ANS
- Preganglionic autonomic fibres
2. Postganglionic autonomic fibres
What are the axons that form synapses with ganglion cells called?
Preganglionic autonomic fibres
What are the axons that innervate effector cells?
Postganglionic autonomic fibres
What is different about the postganglionic neurone?
It has many varicosities from which the neurotransmitter is released
What is the neuroransmitter of the preganglionic nerves?
Acetylcholine
What are the neurotransmitters of the postganglionic nerve?
Acetylcholine and Noradrenaline
What do both post and pre ganglionic nerves have?
Non - adrenergic non - cholinergic neurotransmission (Transmitters and modulators)
What are 4 examples of non-voluntary homeostasis processes:
- Heartbeat
- Contraction of smooth muscle in organs and blood vessels
- Exocrine secretions - hormonal
- Energy metabolism (liver)
What is the difference between sympathetic and parasympathetic systems?
They function separately and have opposing effects in some states
What is sympathetic activity?
Level of perceived threat (fight or flight). Increased HR, blood sugar, hair erected etc
What is parasympathetic activity?
Homeostasis. Rest and digest
Give a brief 4 step run through of the ParaS NS
- Preganglionic axons emerge from cranial and sacral regions of CNS
- Preganglionic axons form synapses in ganglia near to effector tissues
- Sacral nerves - form pelvic plexuses
- Pre ganglionic fibres are LONG, post ganglionic fibres are SHORT
What are the 3 different chains the pre ganglionic sympathetic axons can terminate in?
- Paravertebral sympathetic chains
- Prevertebral ganglia/plexuses - abdominal cavity
- Adrenal medulla - 10th/11th segment
