Lodge 1 Flashcards
- INVOLUNTARY
- Transmits information from the CNS to smooth muscle, cardiac muscle, and glands.
- Two neurons connect the central nervous system to organ (preganglionic and postganglionic neurons)
Autonomic nervous system
- VOLUNTARY
- Transmits information from the CNS to skeletal muscles
- Controls both voluntary and reflex muscle movements
- Only one neuron connects the central nervous system to muscle
Somatic nervous system
The ______ maintains the internal environment of the body (homeostasis)
autonomic nervous system
ANS regulates critical involuntary functions including…
- respiration
- circulation
- GI
- temperature
- endocrine & exocrine glands
Two divisions of ANS
- Parasympathetic system (rest and digest)
* Sympathetic system (fight or flight)
• Craniosacral
• Primary responsibility is conserving &
replenishing energy
• Active during rest or digestion hence “rest-and-digest”
• Works dynamically with the sympathetic system to maintain homeostasis
The Parasympathetic System
- Thoracolumbar (T1-L2)
- Primary responsibility is action
- Active during vigorous exercise, excitement (stress), or emergencies “fight or flight”
The Sympathetic System
Autonomic innervation of sweat gland is _____ (origin T2-L2).
Sympathetic
Many (most) visceral organs are innervated by ____ ANS division(s).
both
Dual innervation can be ____ or _____.
- Antagonistic
- Synergistic/co-operative
Some organs that receive ONLY sympathetic innervation:
- Piloerector Muscles
- Sweat Glands
- Blood Vessels*
Examples of antogonistic innervation
- The eye (radial fibers-sympathetic; circular fibers-parasympathetic)
- The heart (parasympathetic decrease heart rate and force, sympathetic increase)
Examples of synergistic innervation
- Reproductive system (parasympathetic-erection; sympathetic-ejaculation)
- Salivation (parasympathetic-increase gland secretion; sympathetic-vasoconstriction=more viscous saliva)
Post-ganglionic neurons utilize different ______.
neurotransmitters
Neurons classified as either cholinergic (contain ______) or adrenergic (contain ______).
- Acetylcholine
- Norepinephrine
Norepinephrine is released from _______ sympathetic neurons only.
Postganglionic
Catecholamine synthesis
- Phenylalanine
- Tyrosine
- L-DOPA
- Dopamine
- Norepinephrine
- Epinephrine
Catecholamine transmission activity dependent on release from vesicles, inactivation is caused by…
- Re-uptake (most important)
- Enzymatic degradation
responses to adrenergic agonists is similar to sympathetic nervous system activation
Sympathomimetics
Ways that andrenergic agonists act
– Direct receptor activation
– Promotion of NE release
– Inhibition of NE Reuptake
– Inhibition of NE Inactivation
Does NE excite or inhibit organs?
It can do both depending on the receptor
Receptors are all _____ and are divided into ______.
- GPCRs (7-TM receptors)
- alpha and beta
a1 and B1 receptors produce _____, white a2 and B2 produce ______.
- Excitation
- Inhibition
- 7-TM receptor
- GPCR (coupled to Gq)
- Increases [Ca2+]i
- Excitatory
a1 Adrenergic Receptors
a1 Adrenergic Receptor localization
primarily in smooth muscle (blood vessels, eye, bladder, urinary tract, male sex organs, uterus,)
- Vasoconstriction of blood vessels
- Contraction of the radial muscles of the eye (dilation of pupil) • Contraction of bladder
- Increase tone in urinary tract
- Contraction of uterus (pregnancy)
- Male ejaculation
a1 Adrenergic Receptors functions
- 7-TM receptor
- GPCR (coupled to Gi)
- Decreases cAMP
- Inhibitory
a2 Adrenergic Receptors
a2 Adrenergic Receptors localization
primarily located on presynaptic nerve terminals (CNS and PNS)
- Inhibitory autoreceptor
* Regulate (decrease) neurotransmitter release
a2 Adrenergic Receptors functions
- 7-TM receptor
- GPCR (coupled to Gs)
- Increases cAMP
- Excitatory
B1 Adrenergic Receptors
B1 Adrenergic Receptors localization
primarily located in the heart
- 7-TM receptor
- GPCR (coupled to Gs)
- Increases cAMP
- Inhibitory
B2 Adrenergic Receptors
B2 Adrenergic Receptors localization
lungs, gastrointestinal tract, uterus, vascular smooth muscle (heart, lung and skeletal muscle), liver
- Lungs: bronchial dilation
- GI tract: decreased motility
- Uterus: relaxation of uterine smooth muscle
- Blood vessels: Selective vasodilation (c.f. a1)
- Liver: promotes glycogenlysis (glycogen –> glucose) and gluconeogenesis (generation of glucose)
B2 Adrenergic Receptors function
Norepinephrine is devoid of ____ activity at low doses
B2
Cardiovascular effects of epinephrine
• ↑ heart rate & force (β1) • ↓ TPR (β2) (although some α1 vasoconstriction) • ↑ systolic due effects on heart • ↓ diastolic due to vasodilation
Cardiovascular effects of norepinephrine
•↑↑ TPR (α1)
(noβ2 vasodilation)
•↑ systolic & diastolic due to vasoconstriction
•Reflex ↓ in heart rate
- Drug of Choice (DOC) for anaphylactic reactions (reverses bronchoconstriction)
- tx of asthma & COPD (bronchodilator b2)
- tx of cardiac arrest (1/3 saved with EPI & 2/3 with DC countershock)
- vasoconstrictor (a1) agent with local anesthetic drugs.
- DOC for priapism – injected into the corpus cavernosa (vasoconstrictor a1)
Epinephrine (Adrenalin)
Side effects of Epinephrine (Adrenalin)
- Angina, arrhythmias (b1)
- Hypertension -> cerebral hemorrhage (a1) - Pale skin (a1)
- Acute renal failure (a1)
- tx asthma & COPD
- Potent bronchodilators
Albuterol – b2 agonist
Side effects of Albuterol – b2 agonist
- Mainly tremor
- Tachycardia etc (systemic not inhalation)
a1 agonist mediated vasoconstriction in dentistry
- Epi/NE are widely utilized as a potent vasoconstrictor agents
- Selectivity provided by topical application
- Epinephrine is often used to prolong the duration of anesthetic action
- Epinephrine is also used in gingival retraction cords
– Cardiac arrhythmia (any agent with b-activity)
– Angina (any agent with b-activity)
– Hypertension (a1)
– Cerebral hemorrhage (anything that increases BP) – Pulmonary Edema (increased DBP)
Cardiovascular effects of sympathomimetics
– Anxiety, Headache, hyperactivity, insomnia
CNS effects of sympathomimetics
– Nausea, tremors (b2)
Other effects of sympathomimetics
