Peripheral Nervous System Flashcards
What does the PNS do?
Transmits information to and from the brain and spinal cord
Axons of the somatic component go to?
Sensory and motor axons associated with activity in the muscles, the joins and the skin
Axons of the visceral component (autonomic NS) go to?
Axons carrying nerve impulses to the glands, organs and blood vessels
Incoming (afferent) axons are located in which root?
Dorsal (posterior) root
Outgoing (efferent) axons are located in which root?
Central (anterior) root
What is a ganglion?
A swelling on the dorsal root is called the dorsal root ganglion which is where all the cell bodies of sensory neurons sit
What is a motor unit?
One lower motor neuron and all the muscle fibres it inner ages
What 2 mechanisms controls the strength of a muscle contraction?
Frequency and recruitment
How many nerve plexus’ are in the body?
4
What are the 3 types of reception found in the body?
Cutaneous receptors, proprioceptors, nociceptors
What are the 2 types of cutaneous receptors? What do they respond to?
Mechanoreceptors - respond to mechanical forces such as touch, pressure, vibration and stretch
Thermoreceptors - respond to temperature
Nociceptors - respond to noxious stimuli and result in the sensation of pain
What is a dermatome?
An area of skin supplied by all the sensory nerve fibres of one spinal nerve
What are dermatome maps used for?
To determine the source of pain by identifying the area of skin innervated by a specific spinal nerve
What does it mean that peripheral nerves are ‘mixed’ nerves?
They contain sensory (afferent) and motor (efferent) neurons
What are the 12 cranial nerves and what are they associated to?
Learn the table
What are the 2 divisions of the ANS?
Sympathetic and Parasympathetic
Which system is the ‘fight or flight’ system?
Sympathetic
Which system is the ‘rest and digest’ system?
Parasympathetic
ANS nerve fibres are larger or smaller than those of the somatic nervous system?
Smaller
What are some actions of the sympathetic nervous system?
Increases heartbeat, regulates blood, increase ventilation, raise glucose in blood, dilate pupils, stimulate sweat glands
What is the chain of ganglion?
The sympathetic nervous system structure is in a chain. Each ganglion is linked to the next from the base of the skull to the coccyx.
What are some of the actions of the parasympathetic nervous system?
Decreases heart rate, slows breathing, constricts pupils, stimulates digestion
Where are the ganglion of the parasympathetic nervous system?
Near the structure supplied by the nerve. Eg. the heart.
