Lecture 4 - Autonomic Nervous System Flashcards
Why study the autonomic nervous system?
- homeostasis (tightly controlled internal environment)
- drug actions
- drug side effects
Explain the nervous system tree
NS:
- CNS
- PNS
PNS:
- motor nerves
- sensory nerves
Motor nerves:
- autonomic (movement of smooth muscles ex. intestines)
- somatic (movement of skeletal muscles)
Autonomic NS:
- parasympathetic
- enteric
- sympathetic
*we will be focusing on parasympathetic/sympathetic!!
sensory nerves are known as ??
afferent nerves (info from the periphery flows into CNS)
motor nerves are known as ???
efferent (info flows from the CNS to the periphery)
-results in peripheral change (motor)
somatic nervous system is ___ controlled
consciously
PNS and SNS are both _____ systems
efferent (motor)
“visceromotor”
PNS and SNS involve regulation of our ____ environment
internal
out of our control
PNS and SNS both involve _ neutrons that synapse in a peripheral ganglion
2
What 3 things do the PNS and SNS innervate?
- glands
- smooth muscle
- cardiac muscle
in daily life - vast majority = ?
parasympathetic
you’re relaxed, digesting, not expending energy
ergo tropic = ?
energy expenditure
*this is part of SNS
fight or flight = ?
sympathetic
rest and digest = ?
parasympathetic
trophotropic = ?
leading to growth
(energy storage)
*this is part of PNS
Where is SNS innervated?
thoracic lumbar segments
Where is PNS innervated?
cranial and sacral segments
T or F:
SNS - can pick and choose which organ to activate
False
PNS - can pick and choose which organ to activate
SNS - usually has to affect the whole body
If you’re in danger of dying or running from a gorilla (RIP Harambe) or crap like that = ___ activated
SNS
If you’re just chillin (like a villain) = ___ activated
PNS
SNS has ___ preganglionic axon and ___ postganglionic axon
short preganglionic axon
long postganglionic axon
PNS has ___ preganglionic axon and ___ postganglionic axon
long preganglionic axon
short postganglionic axon
i.e. it is right near it’s target so it can pick and choose organs ??
All preganglionics release ___ and are ________
Ach
excitatory (+)
Symp postganglionics release ___ and are ??
NE
excitatory (+) or inhibitory (-)
Parasymp postganglionics release ___ and are ??
Ach
excitatory (+) or inhibitory (-)
PNS targets ?
organs of head, neck, trunk, & external genitalia
SNS targets ?
- organs of head, neck, trunk & external genitalia
- adrenal medulla
- sweat glands in skin
- arrector muscles of hair
- all smooth vascular smooth muscle
SNS is distributed where?
essentially all tissues (because of vascular smooth muscle)
PNS is distributed where?
only head, neck, truck, and external genitalia
-never reaches limbs or body wall (except for external genitalia)
____ is catabolic (expend energy)
SNS
____ is anabolic (save energy)
PNS
T or F: you can have dual innervation of many organs and have it act like a brake and accelerator to provide more control
TRUE
What would SNS do to:
heart
increase heart rate
increase BP
What would SNS do to:
blood vessels
blood vessels constrict and allow more blood to move to to the muscles
What would SNS do to:
intestine
inhibit digestion/absorption
What would SNS do to:
bladder
relax bladder (constrict sphincter)
What would SNS do to:
airways
alveolar dilation (allow more air to get into lungs)
What would PNS do to:
heart
decrease heart rate
decrease BP
What would PNS do to:
blood vessels
blood vessels dilate
(go wherever it needs to)
-decrease BP