skin & autonomic NS (b1- SMS) Flashcards
the 2 divisions of the autonomic nervous system are located where?
Sympathetic NS: thoracolumbar spinal cord & adrenal medulla
Parasympathetic NS: cranial nerves (II, IV, IX, X) and sacral spinal cord (S1- S4)
from these centers, fibers extend & form ganglia, and eventually reach their respective effector organs
A 22-year-old woman on a camping trip has underestimated the cool evening temperatures, so she wraps herself in a thin sheet of polyester film with a reflective surface (Mylar), also known as an emergency blanket or space blanket. She feels warm immediately. Which heat loss mechanism most likely accounts for the effectiveness of this reflective blanket?
E) Radiation
A 24-year-old student goes hiking in the Thar Desert during spring break. The environmental temperature is 105°F and the relative humidity is 20 percent. Which option best describes the major mechanism of heat loss in this student?
Evaporation
would have been conduction/convention if humidity
what does the autonomic nervous system control + what are some functions?
controls visceral (vegetative) functions - means involuntary operations of internal organs
functions:
- respiration
- digestion
- salvation
- sexual arousal
- cardiac activity
- vasomotor activity
outflow path of ANS
commands through special motor neurons called visceral motor neurons
- these neurons start in the intermedio-lateral horn of the spinal cord (where autonomic info flows out from) & are preganglionic neurons — they send signals to autonomic ganglia, which then relay to target organs
control centers of the ANS
brain is in charge, specifically:
hypothalamus: controls hunger, thirst, temp, sexual behavior, etc.
brain stem (medulla, pons, midbrain): houses vital centers: cardiac, respiratory, vasomotor
These areas are influenced by higher brain centers like the cortex & limbic system - can influence ANS during stress, emotions, etc.
neural pathway difference b/w somatic nervous system (SNS) & autonomic nervous system (ANS) (diff in neurotransmitters too)
somatic (SNS): one single neuron connects CNS directly to the effector (muscle)
- neurotransmitter: ACh
- neuron is somatic motor neuron
ANS: 2-neuron chain from CNS → ganglion then ganglion → effector organ
- divides into preganglionic fiber & postganglionic fiber
- neurotransmitter: sympathetic = norepinerphire, parasympathetic = ACh
2 divisions of the peripheral NS (for own knowledge)
somatic (voluntary control) & autonomic (involuntary control)
adrenal medulla
where epinephrine (adrenaline) & norepinephrine (nor-adrenaline) are released
they’re considered hormones now b/c they were released into the blood
where are preganglionic sympathetic neurons found?
intermediolateral (IML) horn of the spinal cord’s lateral gray matter
where are almost 75% of parasympathetic fibers present?
vagus nerve
parasympathetic system is synonymous with vagal system
sympatho-vagal balance
both sympathetic & parasympathetic nervous systems control the same organs - dynamic balance
list the organs innervated ONLY by the sympathetic division
- blood vessels (sympathetic determines vasoconstriction or vasodilation)
- sweat glands (apocrine & eccrine)
- piloerector muscles (goosebumps)
- adrenal gland
makes sense b/c body doesnt slow down blood supply
organs innervated ONLY by parasympathetic division
- lacrimal gland (tear gland)
- ciliary muscle (accommodate for near vision)
- sublingual salivary gland
postganglionic sympathetic cholinergic fibers
expections that are postganglionic sympathetic fibers that release ACh instead of norepinephrine
- normally postganglionic usually release norepinephrine
these special fibers found in: sweat glands, some blood vessels of skeletal muscles
norepinephrine transporters- NET
reuptake norepinephrine into the adrenergic nerve endings
once back in cytosol, norepinephrine can be broken by monoamine oxidase (MAO) or repackaged into vesicles
2 types of cholinergic (ACh) receptors + subtypes UQ
nicotinic: ion channels (very fast)
- found in: ganglia, NMJ, adrenal medulla
- subtypes: N1 (found at NMJ) & N2 (in autonomic ganglia, adrenal medulla)
called nicotinic bc nicotine can activate them
muscarinic: G-protein coupled (slow)
- found in: effector organs (heart, glands, smooth muscle)
- M1, M3, M5: coupled w/ Gq protein = excitatory
- M2, M4: coupled w/ Gi protein = inhibitory
adrenergic receptors
found on effector organs (heart, blood vessels, lungs, etc.)
2 major types:
α adrenergic: α1 → works on the effector organ (postsynaptic) & α2 → Works on the nerve terminal (presynaptic)
β1, β2, β3
she didnt go into much detail about these
functions of the sympathetic division
heart rate: increased
blood pressure: elevated by generalized constriction of the blood vessels
respiratory airways: open wide to permit maximal airflow
pupils, skeletal blood vessels dilate
digestive & urinary activities inhibited
functions of the parasympathetic division
- heart slows down
- blood pressure drops
- airways construct
- pupil constrict to restrict amount of light
alarm/stress response
simultaneous discharge of all portions of sympathetic NS as a unit
- due to activation of hypothalamus as a results of fear or pain
- prepares body for emergency
enteric nervous system
special division of ANS
- network of neurons that control the GIT
- can function independently (called “second brain” bc of this)
2 types of skin (functionally)
Hairy Skin (Non-glabrous): important for thermoregulation
Non-hairy skin (Glabrous skin): lips, soles of feet, palms of hand, and fingertips
(for grasping and locomotion)
