Lecture 17 Flashcards
Define Somatic information transmission. (give examples)
Stuff we are aware of, have control over. [muscle movement (efferent) and sensory information (afferent) - nose, ears, eyes etc.]
Define Autonomic information transmission. (give examples)
Stuff we are not aware of and don’t have control over. [muscle - heart beating (efferent) and sensory information - blood pressure, respiratory rate, heart rate etc (afferent)].
Where is the cell body and axons located for the somatic efferent division?
- Cell bodies are located in the spinal cord (CNS).
- Axons are located in the spinal nerves (PNS).
What is the effector?
The thing the nerves go to and control. (e.g. muscle fibres)
What is the anatomical organisation of the somatic motor (efferent)?
- 1 neuron (from the spinal cord- CNS) with its myelated axon (PNS) making a synapse with a muscle fibre.
- neuron is the pre-synaptic cell
- muscle fibre is the post-synaptic cell.
What is the name of the junction between a somatic motor neuron and muscle fibre(s)?
Neuromuscular junction (NMJ).
What is the chemical neurotransmitter used in the somatic motor (efferent)?
Acetylcholine (ACh).
What is a motor unit?
Includes 1 motor neuron + all the muscle fibre(s) it contacts.
ONLY 1 MOTOR NEURON ( MUSCLE CAN ONLY BE TOLD TO DO 1 THING AT A TIME)
How many neurons are involved in the autonomic nervous system and where are each of their cell bodies and axons located.
2 Neurons involved
- Neuron 1 has its cell body in the spinal cord (CNS) and its axon is the PNS.
- Neuron 2 has its cell body and its axon in the PNS.
What is the Autonomic ganglion?
Collection of the cell bodies of peripheral neurons involved in the autonomic division of the nervous system.
What is the anatomical organisation of the autonomic nervous system?
Neuron 1 from the CNS forms synapse with the autonomic ganglion which is in the PNS.
Neuron 2 from the autonomic ganglion then forms a synapse with the effector (e.g. muscle).
Which neurons are myelated in the autonomic nervous system of the nervous system?
- Neuron 1 is myelated
- Neuron 2 is not myelated
What are the 2 classifications of both neuron 1 and neuron 2 in the autonomic nervous system?
Neuron 1 - Pre-synaptic & Pre-ganglionic.
Neuron 2 - Post-synaptic & post-ganglionic.
What Neurotransmitter are used by both neurons?
Neuron 1 - Acetylcholine (ACh)
Neuron 2 - Acetylcholine (ACh) or noradrenaline (NE) - (ONLY NEURON TO USE 2 DIFFERENT NEUROTRANSMITTERS).
What are the 2 types of autonomic efferents? (define them)
Sympathetic - used for stressful responses
Parasympathetic - used in restful situations
What are the effects of both the Sympathetic and Parasympathetic autonomic efferents?
Sympathetic:
- increases heart rates
- increases blood flow to muscles (constricts blood vessels to skin and viscera)
- decreases gastric motility
- decreases salivation
- increases pupil size
- increases sweating
Parasympathetic:
- decreases heart rate
- increase gastric motility
- decreases pupil size
- increases salivation
What are the structural and neurotransmitter differences between sympathetic and parasympathetic nervous systems?
Sympathetic nervous system:
- Sympathetic ganglion close to the CNS = short axon of neuron 1 and long axon of neuron 2
- Uses noradrenaline / norepinephrine. (NE)
Parasympathetic nervous system:
- Parasympathetic ganglion further away from the CNS = long axon of neuron 1 and short axon of neuron 2.
- Uses Acetylcholine. (ACh)
Where does the Sympathetic nervous system leave from the CNS and what is the position of the ganglia?
- Axons of the Pre-ganglonic cells leave the CNS from the Thoracolumbar levels of the spinal cord. (between T1 and L2)
- Axons extend a short distance (as sympathetic ganglia are located close to the CNS)
- Sympathetic ganglia form a chain (sympathetic chain)
- Synapse and cell body of the post-ganglionic neuron is located in the sympathetic ganglion.
Describe the sympathetic chain ganglia and where they are located.
- 21-23 pairs (depending on height)
- Located along the sides of the vertebral column
- Place where the pre-ganglionic neuron (neuron 1) synapses with the post-ganglionic neuron. (neuron 2)
What are the 2 types of sympathetic ganglia?
Chain ganglia:
- 21-23 pairs
- alongside the vertebral column
Collateral ganglia:
- 3 main collateral ganglia
- not included in the chain of ganglia
Where does the Parasympathetic nervous system leave from the CNS and what is the position of the ganglia?
- Axons of the pre-ganglionic neurons leave from the cranial (brainstem) and sacral (spinal cord) levels. (craniosacral nerves)
- Pre-ganglionic axons extend a long distance (as the parasympathetic ganglia are located further away from the CNS and closer to the effector organs).
