Autonomic Nervous System - Nov. 27th

Question 1

Autonomic Branches

. Sympathetic neurons. Parasympathetic neurons
- Short something? long something? Ach and epi Where?

Cholinergic Receptors
bind what?
where are nicotinic receptors found?
where are muscarinic receptors found? response

Answer 1

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

CHOLINERGIC RECEPTORS

• Bind Acetylcholine
• Nicotinic receptors found at the Sympathetic Ganglia. Parasympathetic Ganglia. Neuromuscular junction (skeletal muscle)
• Muscarinic Receptors found at the Parasympathetic effector organs.
  rest and digest response

Question 2

ADRENERGIC Receptors
Alpha 1 (epi and norepi)
- vasoconstricts? sweat? pupil? urine?
Alpha 2 (epi and norepi)
- insulin release? nore release?
Beta 1 (epi and norepi)
- heart rate? kidney?
Beta 2 (only epi)
- blood vessels? bronchioles? gut and uterus?
Beta 3

Answer 2

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

Question 3

Locations for receptors of Ach NORI and EPI. Just a table switch sides

Answer 3

Question 4

Recap of everything. just a table

and Sympathetic and Parasympathetic regions

Answer 4

muscarinic gives Parasympathetic response

Question 5

Sympathetic Effects (Fight or Flight)
Paraympathetic Effects (Rest and Digest)

heart rate? breath? blood vessels? gut? kidney? urine? pupil?

PARA on blood vessels!!!

Answer 5

↑ 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

PARASYMPATHETIC

↓ heart rate and contractility
↓ breathing rate and depth
***No effect on blood vessels
↑ Gut activity and secretions
↑ kidney function and urine output
Pupil constriction

blood vessel affects are all synpathetic> NO PARASYMPATHETIC

Question 6

General senses
Special senses
Visceral senses
Proprioceptors

Answer 6

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

Question 7

Sensory Receptors

Specialized endings, function

Separate cell that signals to afferent neuron, eg.

Receptor Field

Answer 7

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

Question 8

Characteristics of Sensory Receptors

what is the M? different types of M

Answer 8

MAIL
Modality
Adaptation
Intensity
Localization

Modality
- Receptor type
- Each responds to one type of stimulus only
* Except pain

Chemoreceptors
Mechanoreceptors
Proprioceptors

Question 9

Free nerve ending types

Answer 9

Specific types of mechanosensory
stimulation are transduced by
specific types of receptor cells

Question 10

Intensity. how are they coded, and what is the outcome

Adaptation to stimulus

Phasic or fast-adapting receptors
Tonic or slow-adapting receptors

Answer 10

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

Question 11

Localization or Acuity
depends on?

Receptor Field Effect

Answer 11

Ability to distinguish between to stimulus points
Depends on:
- Receptor field size
- Receptor field overlap
- Area of representation in cortex
- Lateral inhibition

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*

BACK
If receptor field size increases acuity or ability to localize decreases
Eg. Back less sensitive than fingers

FINGERS
With more overlap of receptor fields
- Acuity increases
Eg. Fingers

Question 12

Lateral Inhibition

what does it do? because neuron b is at highest frequency? lateral inhibition allows the CNS…?

Answer 12

Receptor fields continuous
Increases “contrast”
So increases acuity

Because neuron B is firing at the highest freq., it inhibits A and C via inhibitory pathways to a greater extent than A and C inhibit B.

Lateral inhibition allows the CNS to more accurately locate the source of stimulation, which can help guide necessary or beneficial responses.

inhibit A and C, and turn off the neighbours
A and C also inhibit A