Physiology. Flashcards
What are the two divisions of the autonomic nervous system?
Sympathetic and Parasympathetic.
What are the two systems of the somatic nervous system?
Motor and sensory.
What is the submucous plexus?
Sensory neurons that detect changes in chemical environment.
What is the myenteric plexus?
Motor/motility of GIT.
What is noradrenaline?
Excitatory neurotransmitter of postganglionic sympathetic neurons.
What is acetylcholine?
The excitatory neurotransmitter of postganglionic sudomotor (has to do with sweat glands) neurons.
What tissues are co-innervated by both sympathetic and parasympathetic?
Heart.
GIT.
Cranial vessels.
What tissues are only sympathetic?
Skin and vessels.
What are some sympathetic system features?
Increase heart rate.
Increase the force of contraction.
Vasoconstriction.
What are some parasympathetic system features?
Decrease heart rate.
Vasodilation.
Pupillary constriction.
What are some sympathetic system hormones?
Epinephrine, norepinephrine.
What is the parasympathetic system hormone?
Acetylcholine.
Epinephrine/Adrenaline acts on which type of receptors?
Alpha 1 - Vasoconstriction.
Beta 1 Positive Effect.
Beta 2 Vasodilation.
Norepinephrine acts on which type of receptors?
Only on Alpha 1 and Beta 1.
When is the vasoconstrictive drive increased?
In Heart failure, essential hypertension, metabolic syndrome and COPD.
What is sympathectomy?
Removal of sympathetic ganglia at T2-T4 - results in palmar hyperhidrosis (interrupts sympathetic outflow).
Acetylcholine is the excitatory neurotransmitter at which synapses?
Nicotinic and muscarinic synapses.
What do postganglionic sympathetic neurons release?
Noradrenaline (adrenergic receptors).
What do parasympathetic postganglionic neurons release?
Acetylcholine (muscarinic receptors).
What do neurons generate?
A negative potential called the resting membrane potential.
Where is the action potential propagated?
It is propagated along the length of the axon.
Electrical signals arise from what?
Ion fluxes - when a cell membrane is being selectively permeable.
What is an All-or-none response?
The strength of the stimulus does not matter. If above threshold, nerve/fibre will fire.
What do we know about fibre diameter?
The greater the diameter, the faster the AP spreads.
What do we know about myelination?
Myelinated nerves conduct faster.
What are some features of myelin?
Less leakage.
Less Na.
Saltatory conduction at nodes of ranvier.
What is multiple sclerosis?
Autoimmune disease.
Damaged myelin.
What are the different types of synapses?
Chemical.
Electrical.
What happens when the action potential reaches the axon terminal?
Voltage-gated Ca channels open.
What triggers the fusion of synaptic vesicles to presynaptic membrane?
Influx of Ca.
What is Glutamate?
An excitatory neurotransmitter, which cause opening of Na channels.
What causes depolarisation of postsynaptic neuron?
Influx of Na.
What is gamma-aminobutyric acid?
Inhibitory neurotransmitter, causes opening of Cl channels.
What causes hyperpolarisation of postsynaptic neuron?
Influx of Cl.
What do excitatory postsynaptic potential lead to?
Decrease in membrane potential - AP is generated in postsynaptic neuron.
What do inhibitory postsynaptic potentials lead to?
Pushes membrane potential further away from firing threshold.
What are the two types of adrenergic receptors?
Alpha and Beta.
Which enzyme is responsible for the formation of acetylcholine?
Choline acetyltransferase.
Which enzyme is responsible for the breakdown of acetylcholine?
Acetylcholinesterase.
What if the enzyme acetylcholinesterase was inhibited?
There will be a buildup/increase of acetylcholine.
What is glutamate used for?
Blockage of glutamate receptors have a protective role for tissues at risk in acute stroke and in brain injury.
What is the major inhibitory neurotransmitter in the brain?
GABA.
What is myasthenia gravis?
Affects NMJ.
Antibodies against acetylcholine receptors.
What are the symptoms of myasthenia gravis?
Tiredness by end of day.
Eye drooping.
Muscle fatigue.
What is the treatment for myasthenia gravis?
Inhibition of acetylcholinesterase.
Which types of muscles are striated?
Skeletal and Cardiac.
Which type of muscle is unstriated?
Smooth.
What do cardiac muscle act as?
Functional syncytium.
What are the components of muscle?
Sarcolemma.
Smooth endoplasmic reticulum.
Sarcoplasmic reticulum.
What is thick filaments?
Myosin.
What are the thin filaments?
Actin, troponin, and tropomyosin.
What is actin?
Contains myosin binding sites.
What is tropomyosin?
Covers myosin-actin binding sites.
What is troponin?
Troponin T.
Troponin C.
Troponin I.
What is troponin T?
Attaches troponin to tropomyosin.
What is troponin C?
Ca binding protein - plays a role in contraction.
What is troponin I?
Inhibits interaction between myosin and actin.
Which biomarker is most sensitive for myocardial infarction?
Troponin I.
CK-MB.
What is rigor mortis?
Muscular stiffening and rigidity caused by lack of ATP (death).
Where is smooth muscle found?
GIT, bladder, uterus etc.
What is the function of smooth muscle?
Produce motility and maintain tension.
Name a excitatory and inhibitory substance?
Glutamate and GABA.
Name two affects of increased sympathetic activity?
Increased Heart rate and pupillary dilation.
Name two affects of parasympathetic activity?
Decreased heart rate and pupillary constriction..
How does acetylcholine act on the GIT?
Increase motility.
What is the law called, when there is stimulation, there is gonna be AP?
All-or-none response.
What happens if there is no myelin?
Slower action potential.
What does Alpha-1 do?
Vasoconstriction in blood vessels.
What does Beta-2 do?
Vasodilation in blood vessels
