PS120: Autonomic Nervous System Flashcards
(65 cards)
Define Autonomic Nervous System
the part of the nervous system that controls the involuntary acts in our body
What are involuntary acts of our body?
activity of the…
- smooth ms
- cardiac ms
- gland secretion
What are the origins of the ANS?
from limited area of CNS:
- cranial nerves 3, 7, 9, 10
- all thoracic segments
- L1, L2, L3 segments
- S2, S3, S4 segments
What are the 2 systems the ANS is divided into?
- Sympathetic NS
- Parasympathetic NS
What are the properties of SNS?
- the components of this system get activated all in one time
- (i.e) they act in sympathy with each other, hence the name sympathetic NS
- prepares body for increased activity, thus it is activated in stressful situations (emergency conditions)
- catabolic (energy consuming)
Which ANS system is energy-consuming?
The SNS; it is catabolic and activates muscular exercise, fear, flight, and fight.
What are the properties of the PNS?
- the components of this system are not activated all in one time
- (i.e.) each component acts separately.
- prepares body for recovery & repair, so it active during rest
- anabolic (energy preserving)
Why are the PNS’s parts not activated at the same time?
Generalized parasympathetic NS stimulation may be fatal.
What are the 2 types of relationship between the ANS divisions?
- Anatomical relation
- Functional relation
What are the types of anatomical relation between PNS and SNS?
- double innervation
- single innervation
What is double innervation and where is it found?
- both symp and parasymp innervation for a given organ
- majority of organs have double innervation
What is single innervation & where is it found?
there are organs that only have symp. innervation. these include:
- skin
- limbs: (blood vessels of skeletal ms.)
- abdominal & thoracic walls: (blood vessels & skin of skeletal ms.)
- ventricles of the heart
- spleen
- adrenal medulla
The adrenal medulla’s innervation is:
single (symp only)
Types of functional relations between PNS & ANS include:
- antagonism
- synergism
- similarity
- dominance
- reciprocal
Reciprocal is the same as ____ because…
Antagonism, as they both have a relationship where when one system is stimulated, the other system is inhibited.
Antagonist action in the heart:
Sympathetic: tachycardia
Parasympathetic: bradycardia
Antagonist action in the bronchi:
symp: bronchodilation
parasymp: bronchoconstriction
Antagonist action in GIT:
symp: decrease in motility
parasymp: increase in motility
define synergism
complementary action, when the two systems help each other
example of synergism:
sexual intercourse
- parasymp: causes erection of erectile tissue (clitoris & penis) and the secretion of seminal vesicle fluid & prostate gland
- symp: cause ejaculation & orgasm
define similarity
exceptionally the two systems may have similar action on the same organ
example of similarity:
symp and parasymp stimulation of salivary secretion.
- symp: leads to viscid (trophic) salivary secretion that is: (little amount, poor in water, rich in enzymes)
- parasymp: leads to watery (true) salivary secretion that is: (large in amount, rich in water, poor in enzymes)
define dominance
when one system is dominant to some organs to give them tone DURING REST
- milds continuous activity during rest
example of sympathetic dominance
vasoconstrictor tone keeping the diametre of blood vessels approximately 1/2 the max diametre; keeps ABP constant