12.1 Autonomic and CNS Flashcards
1
Q
Central Nervous System
A
- Consists of brain and spinal cord
- Brain is the main functional unit
- Spinal cord is main processing unit (movement/reflex)
2
Q
Peripheral Nervous Syste
A
- Split into afferent and efferent
Afferent - Sensory neurons that carry sensory information towards the CNS
Efferent - Motor neurons that carry impulses from CNS to muscles to produce movement - Also divided into Somatic and Autonomic
3
Q
Somatic PNS
A
- Controls voluntary movement through skeletal muscle and mediation of involuntary reflexes
4
Q
Autonomic Nervous System (cont)
A
- Controls involuntary activities in smooth muscle, secretory glands, and visceral organs.
- Functions for homeostasis, stress response, and body tissue repair.
- Acetylcholine and norepinephrine are the major neurotransmitters for ANS.
5
Q
Autonomic Nervous System (ANS)
A
Divided into Parasympathetic Nervous System (PSNS) and Sympathetic Nervous System (SNS)
Sympathetic - Fight or Flight Response preparing the body for intense physical activity
Parasympathetic - Relaxes body and inhibits/slows many functions
6
Q
Physiological Effects of SNS
A
- Increase heart rate, arterial blood pressure and cardiac output
- Increased blood glucose, pupillary dilation, rate of cellular metabolism
- Increased blood flow to brain, heart, skeletal muscles
- Increased rate/depth of respiration
7
Q
Adrenergic Receptors
A
- These include alpha, beta, and dopamine receptors
- Agonist means stimulator
- Antagonist means inhibitor/blocker
8
Q
Stimulation of SNS Receptors
A
- Stimulation of SNS receptors produces adrenergic effects and blockage produces antiadrenergic effects
- Stimulation of SNS receptors produces adrenaline effects on the body
9
Q
Physiological Effects of PSNS
A
- Dilation of blood vessels in the skin
- Decreased heart rate
- Increased secretion of digestive enzymes
- Pupillary constriction
- Contraction of smooth muscle in bladder
- Contraction of skeletal muscle
10
Q
Stimulation of PSNS
A
- Stimulation produces cholinergic effects and blockages produce anticholinergic effects
11
Q
Catecholamines (adrenergic agonist)
A
- Contain catechol and an amine group
- Can be nonselective (alpha and beta receptors) or selective
- Short duration
- Cannot be given orally
- Does not cross BBB
- Destroyed by COMT and MAO located in liver and intestinal wall
- Examples include dopamine, dobutamine, epinephrine, isoproterenol, norepinephrine
12
Q
Non-Catecholamines
A
- Activates alpha and beta receptors
- Poor affinity so poorly selective
- Long duration
- Can be given orally
- Does not cross BBB
- Destroyed only by MAO so longer half-life
- Examples clonidine, ephedrine, respiratory drugs, mephentermine
13
Q
Alpha-1 Adrenergic Receptors
A
- Vasoconstriction and Mydriasis (Pupil Dilation)
- Homeostasis of skin and mucous membranes (usually topical epinephrine)
- Supplements anesthesia; delays absorption to prolong anesthesia, usually epinephrine
- Hypotension when fluid replacement and other measures fail
- Mydriasis to facilitate eye exam or ocular surgery
14
Q
Alpha-1 Adrenergic Receptors Adverse Effects
A
- Hypertension due to vasoconstriction
- Necrosis due to vasoconstriction locally
- Reflex bradycardia - Increased blood pressure stimulates baroreceptors leading to bradycardia. This can compromise tissue perfusion in people with diminished cardiac reserve.
15
Q
Alpha-2 Receptor
A
- No therapeutic action on PNS but significant on CNS