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60 Cards in this Set

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What takes place during depolarization in regards to an action potential
-Excitable cells triggered
-Na in, K out
-Fast Na channel open first
-slow K channels open later
Repolarization
-slow Na channels close
-slow K channels cont to open
-conductance of K peaks @ mid-repolarization
After-depolarization
-Occurs after spike potential and after repol is approx 70% complete
-rate of repol is decreased
-conductance of K and Na decreases
Hyperpolarization
-Occurs at end of AP
-membrane potential becomes more negative than resting pot.
-conductance of Na returns to resting level
-conductance of K remains elevated above resting level
What is the role of neurotransmitters?
to cause exciatatory or inhibitory potentials
Where are excitatory and inhibitory NTS found?
In both, PNS and CNS
What is the hallmark of Alzheimer's Disease?
Destruction of neurons that release ACH in the brain
Area between presynaptic and post synaptic cell which contains acetylcholinesterase
Synaptic cleft
This period of the Action Potential constitutes:
1. Resting membrane potential
2. Ends when threshold is reached and action potential begins
3. Determined by extracellular K Concentration
The latent period
Actions of ACH at the neuromuscular junction and at the heart
Excitatory at neuromuscular junction- Acts to open chemically gated ion channels

Inhibitory in parasympathetic fibers of Vagus nerve (cranial nerve X)
- Innervates the heart
- Slows the heart rate down
Types of Neurotransmitters
1) acetylcholine 2) amino acids 3) biogenic amines 4) neuropeptides 5) gases
Excitatory Amino Acid NTS found in the brain
Glutamate and Aspartate
Inhibitory Amino Acid NTS
1.GABA-primarily in the brain
2.Glycine-Primarily in the spinal cord
How does Valium work?
It enhances the the action of GABA with further inhibition
Types of Biogenic Amines, also called catecholamines and are actively transported back into the synaptic bulb after release
NOREPINEPHRINE (NE) EPINEPHRINE
DOPAMINE (DA)
SEROTONIN (5-HT)
Implicated in maintaining arousal, dreaming and mood regulation
NOREPINEPHRINE (NE) & EPINEPHRINE
Where is Epi found?
In the Brain and Spinal Cord
Where is Norepi found?
NE found in brain, spinal cord, GI tract, Sympathetic endings
What are the actions of Dopamine
Involved in emotional responses
Regulates gross automatic movements of skeletal muscles
What causes Parkinson's Disease?
Degeneration of neurons producing dopamine causes Parkinson's Disease
Where is Dopamine found?
DA is found in the brain, retina, sympathetic ganglia
Serotonin (5-HT) is involved in?
Induces sleep, sensory perception, temperature regulation and control of mood
Name a drug that inhibits serotonin reuptake
Prozac, its an anti-depressant
What is the action of Angiotensin II
stimulates thirst
Name some Neuropeptides
May also act as hormones

Angiotensin II
Oxytocin
Antidiuretic hormone, Enkaphalins and endorphins
Atrial Natriuretic Peptide, Gastrin
What type of effects do Enkaphalins and endorphins have
analgesic effects
This type of NTS is released by endothelial cells lining blood vessels - Causes relaxation and vasodilation
Nitric Oxide
What are the effects of Nitric Oxide?
Causes relaxation and vasodilation. Effect is to lower BP
Name some factors that alter the impulses and synapses
Alkalosis
Acidosis
Hypnotics
Caffeine
Drugs
What does alkalosis do to a neuron?
It increases the excitability of neuron
Impulses arise inappropriately - Light headedness, numbness, tingling, nervousness, muscle spasms
What is acidosis and what does it do?
Decrease in pH below 7.3
Progressive depression of neuron activity
Produces apathy and muscle weakness
How do HYPNOTICS, TRANQUILIZERS, ANESTHETICS affect the threshold?
Increases the threshold for excitation
How do CAFFEINE, BENZEDRINE, NICOTINE affect the threshold?
Reduces threshold for excitation
What is the Lambert-Eaton Myasthenic Syndrome?
Autoimmune disorder production of antibodies to presynaptic Ca++ channels leading to decreased presynaptic release of ACH
What is Myasthenia Gravis?
Autoimmune disorder involving production of antibodies to nicotinic ACH receptors
How does botulism work?
It blocks presynaptic Ach release at neuromuscular junction, causing paralysis
How do you get botulism?
Ingestion of endotoxins from improperly cooked foods
What is Tetanus?
causes spasmodic muscle contraction and you get it by
skin exposure to exotoxins which block presynaptic release of Ach
What do cholinergic receptors do?
mediate the actions of acetylcholine (ACh)
The types of cholinergic receptors
nicotinic and muscarinic
Site of muscarinic receptors
at the postganglionic parasympathetic neuroeffector junction in smooth muscle, heart, and exocrine glands
What are the effects of muscarinic receptors
salivation, urination, defecation, pupillary constriction, vasodilation, cardiac slowing, depressed AV nodal conduction, and bronchoconstriction
Name an antagonist of muscarinic receptors
Atropine is antagonist at this receptor (m2)
What is the action of nicotinic receptors
mediate most of the actions of nicotine and some of those ACh
Effects of nicotinic receptors
release of catecholamines from the adrenal medulla, ganglionic transmission, and transmission of the somatic neuromuscular junction
The two types of nicotinic receptors
Nn and Nm
Where are Nn receptors located?
in Ganglia
Where are Nm receptors located?
in the neuromuscular junctions
The two major types of Adrenergic receptors
Alpha 1 receptors are sensitive to blockade by prazosin (Minipress®) postsynaptic
Alpha 2 receptors are sensitive to blockade by yohimbine. Alpha2 (presynaptically on sympathetic postganglionic nerve terminal)
What does activation of the presynaptic alpha 2 receptors do?
inhibits the release of NE
What do Beta receptors do when activated?
generally produce "inhibitory" responses of smooth muscle in which they are located.
Bronchodilation and vasodilation
Classical agonist of beta-receptors
isoproterenol (Isuprel)
Classical antagonist of beta receptors
propranolol (Inderal)
What do Beta 1 receptors do when activated
Beta1 receptors, when activated, produce cardiac positive chrono- and inotropic responses and lipolysis
Name a Selective antagonist of beta 1 receptors
metoprolol (Lopressor®)
Name a Selective beta 2 agonists, which are useful in the treatment of asthma
terbutaline (Brethine)
This drug is a selective alpha1 antagonist, and a non-selective antagonist of both beta1 and beta2 receptors
labetalol (Normodyne)
What are some of the causes for receptor malfunction?
Receptors response to drugs and Diseases such as:

Diabetes
Guillan-Barre
Myasthenia gravis
The effector molecule which catalyzes the conversion of ATP into the "second messenger" cyclic AMP (cAMP)
Adenosine Cyclase
Types of intracellular mediators
Second Messengers
Protein kinases
G-Proteins