ANS 2 Flashcards
Normal sympathetic activity
Targeted homeostatic mechanisms
EX. Metabolization of energy stores, increase cardiac output, sweating, people dilation
Sympathetic activation
Activation of entire sympathetic system, crisis management
Parasympathetic activity
Pupil contraction
Increased digestive activity, secretion and peristalsis
Anaerobic activities (insulin release)
“bathroom activities”
Reduced metabolic function: heart rate and respiration
Sexual arousal
Autonomic communication via the parasympathetic receptors. chlinergic, NT: acetylcholine
Nicotinic receptors
Muscarinic receptors
Nicotinic receptors
ACh binding-> Na channels open-> depolarization (excitatory)
EX. All autonomic postganglionic neurons, adrenal medullae
Mescarinic
ACh binding-> G protein activation-> activation\inhibition of a factor cell activity via secondary messengers.
EX. Increase gland is secretion, decreased cardiac muscle activity
Autonomic communication via the sympathetic receptors. Adrenergic (NT: Norepinephrine (NE) and epinephrine (E)
Alpha receptors
Beta receptors
Alpha-1 receptors
Bind to NE (normal sympathetic control) or E
Stimulate calcium release from ER
Usually excitatory
example: contraction, secretion
Alpha-2 receptors
Decrease cAMP levels
Usually inhibitory
Example: digestive activity
Beta receptors
Bind to epinephrine and norepinephrine
Increase cAMP levels in target cells
Beta-1 receptors
Excitatory: increase cardiac contraction
Beta-2 receptors
Smooth muscle relaxation
Example: respiratory smooth muscle relaxation resulting in vasodilation and bronchodilation
Beta-3 receptors
Stimulates lipolysis in adipocytes.
Signal degradation, or breakdown
Acetylcholine-> acetylcholinesterase Norepinephrine and Epinephrine 1. Monoamine oxidase (MOA) 2. Catechol-O-methyranferase (COMT) 3. Liver
Dual innervation
Opposing (antagonistic) effects at effectors
Present at most visceral organs: digestive track, heart, lungs, eyes
Autonomic tone
To controllable gas/brake pedals in operation at all times
Single innervation
Sometimes only the PSNS or SNS Controls an effector.
Example: Vasoconstriction and reproductive activity
Autonomic receptors that controls autonomic activity
Baroreceptors and chemoreceptors
Autonomic control center: cerebral cortex
Emotions can influence autonomic activity
Examples: fear anxiety and arousal
Autonomic control center: hypothalamus
Primary control center of autonomic activity. Via the connection to the pituitary gland
Autonomic control center: mid brain and brain stem
Cardiovascular control
Respiratory control
Sweating, swallowing, bladder control, pupils, salvation, and digestive secretion
Autonomic control center: spinal cord
Autonomic (short) reflexes
Micturation
Defecation
Sexual arousal
