Autonomic Nervous System - Nov. 27th Flashcards
Mastery
Autonomic Branches
. Sympathetic neurons. Parasympathetic neurons
Cholinergic Receptors
Sympathetic neurons
- Short pre-ganglionic neurons
- Long post-gangionic neurons
- Ach at ganglion, Epi at Effector organ
Parasympathetic neurons
- Long pre-ganglionic neurons
- Short post-ganglionic neurons
- Ach at ganglion and effector organ
- Bind Acetylcholine
- Nicotinic receptors found at the Sympathetic Ganglia
- Parasympathetic Ganglia
- Neuromuscular junction (skeletal muscle)
- Muscarinic Receptors found at the Parasympathetic effector organs
Adrenergic Receptors
Alpha 1 (epi and norepi)
Alpha 2 (epi and norepi)
Beta 1 (epi and norepi)
Beta 2 (only epi)
Beta 3
Alpha 1 (epi and norepi)
- Vasoconstricts blood vessels – heart, muscle, gut,
kidneys, skin
- Increased sweat gland secretion / goose bumps
- Dilates pupils
- Propels urine
Alpha 2 (epi and norepi)
- Inhibits insulin release / constricts gut sphincters
- Decreases norepinephrine release
Beta 1 (epi and norepi)
- Increases heart rate and contractility
- Increased renin from kidney
Beta 2 (only epi)
- Vasodilates blood vessels – muscle, heart
- Bronchodilation
- Relaxes gut wall and uterus
Beta 3
- Lipolysis – fat tissue
- Relaxes bladder
Locations for receptors of Ach NORI and EPI. Just a table switch sides
Recap of everything. just a table
and Sympathetic and Parasympathetic regions
Sympathetic: Thoracic and lumbar regions
Parasympathetic: Cranio-sacral
Sympathetic Effects (Fight or Flight)
Paraympathetic Effects (Rest and Digest)
↑ heart rate and contractility
↑ breathing rate and depth
Blood vessel effects
Vasoconstriction to non-essentials (eg. Gut)
vasodilation to muscle
↓ Gut activity and secretions
↓ kidney function and urine output
Pupil dilation
↓ heart rate and contractility
↓ breathing rate and depth
No effect on blood vessels
↑ Gut activity and secretions
↑ kidney function and urine output
Pupil constriction
General senses
Special senses
Visceral senses
Proprioceptors
General senses
Touch, temperature, pressure, pain, itch, etc.
Special senses
Vision, hearing, smell, taste
Visceral senses
pH, osmolarity, chemoreceptors, etc.
Proprioceptors
Stretch, position, over-contraction
Sensory Receptors
Specialized endings
Separate cell that signals to afferent neuron
Receptor Field
Sensory Receptors
Two types
Specialized endings
of neuron
* Eg. touch
Separate cell that
signals to afferent
neuron
* Eg. Rods and cones
Area of skin that a sensory receptor innervates. Size will vary
Characteristics of Sensory Receptors
Modality
- Receptor type
- Each responds to one type of stimulus only
* Except pain
Chemoreceptors
Mechanoreceptors
Proprioceptors
Free nerve ending types(table)
Intensity. how are they coded, and what is the outcome
Adaptation to stimulus
Phasic or fast-adapting receptors
Tonic or slow-adapting receptors
Coded by frequency. Since AP’s are all-or-none
Higher stimulus will also stimulate more fibres
When the neuron stops sending AP’s in response to a continuous stimulus
Phasic or fast-adapting receptors
- Responds to change in stimulus
- Eg. Temp, touch, smell
Tonic or slow-adapting receptors
- Continues to send AP’s in response to constant
stimulus
Eg. Pain, vision, proprioceptors
* Non-adapting
Localization or Acuity
Receptor Field Effect
Ability to distinguish between to stimulus points
Depends on: Receptor field size, Receptor field overlap
Area of representation in cortex, Lateral inhibition
even if 2 points hit the skin, if they are in the same receptor field, you will only feel one*
If receptor field size increases acuity or ability to localize decreases
Eg. Back less sensitive than fingers
With more overlap of receptor fields
- Acuity increases
Eg. Fingers
Lateral Inhibition
Receptor fields continuous
Increases “contrast”
So increases acuity
inhibit A and C, and turn off the neighbours
A and C also inhibit A
