ANS Flashcards
What does the ANS control?
Involuntary activities:
- Smooth muscle
- Cardiac muscle
- Various glands
What are the 2 divisions of the ANS?
- Sympathetic NS
- Parasympathetic NS
What nerves does the parasympathetic NS affect?
- Brainstem:
- CN 3,7,9 - head structures
- CN 10 (vagus) - thoracic and abdominal organs
- Sacral spinal cord:
- S 2,3,4 - pelvic organs
What nerves does the sympathetic NS affect?
- Thoracic and lumbar regions of the spinal cord T1-L2
Where is the ganglion in a parasympathetic neuron of the ANS?
Close or very near to the effector organ
Where is the ganglion in a sympathetic neuron if the ANS?
Midway
What are the 2 components of the SNS?
- Nervous component
- Endocrine component
What is the endocrine component of the SNS?
- Adrenal medulla - produces and releases adrenaline into the blood stream
What is the ganglion like in the PNS?
- Long pre-gang neuron
- Short post-gang neuron
- Ganglion near or in effector organ
What is the ganglion like in the SNS?
- Pre- and post-gang neurons similar in length
- Synapse in Sympathetic chain or one of the collateral (or pre-vertebral) ganglia or in the adrenal medulla
Where does the PNS generally have actions on?
- Generally had discrete actions on single organs in the body ‘core’:
- Salivary gland; heart
What are the conservative, anabolic effects of the PNS?
- Storing energy - digestion etc
- Slowing heart
Where does the SNS generally have actions on?
- More widespread actions, often affecting whole body
* distribution of sympathetic nerves; circulating adrenaline
What is the SNS associated with?
- Homeostasis
- blood pressure, thermoregulation
- Fight, flight or fright
- meeting demands of active muscle
What is the effect of the ANS on smooth muscle?
- Blood vessels in various parts of the body
- Bronchi, bronchioles
What is the effect of the ANS on the heart?
- GIT - change in circulation of GIT will have effect on heart
- Rate, force of contraction
What is the effect of the ANS on glands?
- Salivary glands
- Gastro-intestinal glands
- Sweat glands
Does the ANS have an effect on metabolism?
Yes, a major effect
Does the ANS control breathing?
NO, the breathing muscles are skeletal muscles, and are controlled by somatic nerves (e.g. phrenic nerve) - not conscious but not controlled by ANS
What are the PNS and SNS effects on the iris?
PNS - Contraction
SNS - Contraction
What are the PNS and SNS effects on the ciliary muscle?
PNS - Contraction
SNS - Relaxation
What are the PNS and SNS effects on salivary glands?
PNS - Secretion (copious, watery)
SNS - Secretion ( viscous, low volume)
What are the PNS and SNS effects on the lacrimal gland?
PNS - Secretion
SNS - Secretion
What are the PNS and SNS effects on nasal glands?
PNS - secretion
SNS - nothing
