PNS Flashcards
(34 cards)
What do somatic afferent nerves do?
convey information from skin, skeletal muscle and joints
What do somatic efferent nerves do?
convey information to skeletal muscles
What is a dermatome?
an area of skinthat is supplied by a single spina lnerve
What is a myotome?
group of muscles innervated by a single spinal nerve
What do visceral afferent nerves do?
carry information from the viscera (thoracic, abdominal & pelvic organs)
What do visceral efferent nerves do?
innervate the viscera (organs) + periphery (vasculature + sweat glands)
How can visceral efferent nerves be classified?
→ sympathetic
→ parasympathetic
What is the difference in areas being innervated by visceral sympathetic and parasympathetic?
Parasympathetic only innervates the viscera (organs)
What is the difference between a ganglion and a nucleus?
→ Ganglion: collection of cell bodies OUTSIDE the CNS
→ Nucleus: collection of cell bodies INSIDE the CNS
Where are the cell bodies of all PNS afferent nerve fibres?
Spinal ganglia
Where do visceral efferent nerves synapse?
Peripheral ganglion
What is a plexus?
network of interconnecting nerves
How are peripheral nerves arranged?
In fasciculi - 3 layers of connective tissue
What are the 3 layers of connective tissue in fasciculi?
→ epineurium = External vascular layer of fasciculi
→ perineurium = Covers individual fascicles
→ endoneurium = covers individual axons
What 2 classification systems are used to classify peripheral nerves?
→ conductional velocity
→ axonal diameter
How does the conduction velocity system work?
Uses ABC, A = fastest
How does the axonal diameter system work?
Uses Roman numerals I-IV, I = largest diameter
What 2 classification systems are used to classify sensory receptors?
→ source of stimulus
→ mode of detection
How are sensory receptors classified by source of stimulus?
→ detection of internal info e.g. Exteroreceptors
→ detection of internal info eg. proprioceptors, enteroreceptors
What do exteroreceptors detect?
Pain + temperature + touch + pressure
What do proprioceptors detect?
Receptors in muscles + joints, detects movement + joint position
What do enteroreceptors detect?
→ Movement through gut
→ blood ph
Give 3 examples of proprioceptors.
→ joint receptors - found in joint capsules and
detect the start and the end of movement
→ muscle spindles - detect changes in muscle length
→ Golgi tendon organs - detect changes in tension in tendons
Name 5 different types of sensory receptors.
- Chemoreceptors: detect molecules which bind to receptor
- Photoreceptors: detect light in retina
- Thermoreceptors: detect temperature in skin
- Mechanoreceptors: detect mechanical pressure or distortion
- Nociceptors: detect tissue damage, interpreted as pain
