Neuromuscular Flashcards
What makes up the basal ganglia?
striatum (caudate–putamen), lenticular nuclei (the putamen, globus pallidus externus and internus), ventral striatum, substantia nigra, and subthalamic nucleus
What is CSF composition like compared to blood?
Lower pH (7.33), lower protein content, lower glucose and potassium
Which neurotransmitter isn’t inactivated by reuptake when diffused out of the cleft or pumped into presynaptic nerve endings?
Acetylcholine
Where is the aqueous humour of the eye produced?
ciliary epithelium. It has multiple functions including the maintenance of intraocular pressure and providing nutrition.
Which target tissue of the sympathetic nervous system contains muscarinic acetylcholine (Ach) receptors?
Sweat glands
How does adrenaline differ from noradrenaline?
adrenaline is a more potent vasodilator, greater effect on cardiac tissue because of more potent beta-adrenergic effects, metabolic effects 5-10 times greater, greater increase in CO, less vasoconstrictive effect
Noradrenaline is a more potent activator of the RAAS system, greater effect on TPR
Which neurotransmitter is found predominantly in motor neurons?
Acetylcholine
What is the most common cell in the neocortex?
Pyramidal neuron. Pyramidal neurons are excitatory neurons which release glutamate
What are basket and chandelier cells?
Basket cells and chandelier cells are inhibitory interneurons that release GABA as their neurotransmitter.
What are epyndymal cells?
Ependymal cells line the ventricles and are involved in the production of CSF.
What are stellate cells?
Stellate cells are excitatory interneurons that release glutamate
What happens in the sarcomere with muscle contraction?
As muscle contraction occurs, the actin and myosin filaments overlap with the actin filaments moving towards the central M line as the sarcomere shortens
How many actin filaments surround each myosin fibre
Each myosin fibre is surrounded by six actin filaments
What are thin filaments made of?
Actin
What are thick filaments made of?
Myosin
What is the role of tropomyosin and troponin in muscle contraction?
Tropomysin and troponin are closely related to actin filaments and are involved in the binding of the myosin head to the actin filament during contraction.
Which fibres are the most susceptible to hypoxia?
The beta fibres
Which fibres are most susceptible to local anaesthetic?
B and C fibres, but C fibres are the most
How do action potentials start?
Action potentials are started by an external stimulus with sodium being the initial ion movement
What does stimulation of alpha-1 receptors do?
peripheral vasoconstriction, mydriasis
What does stimulation of B2 receptors do?
relaxation of smooth muscle in the vasculature and bronchi
What does stimulation of B3 receptors cause?
stimulates lipolysis
What does stimulation of A2 receptors cause?
insulin secretion and lipolysis
Where is ADH formed?
Antidiuretic hormone (ADH) is formed mainly by the large endocrine neurons—magnocellular neurons—located in the supraoptic nucleus of the hypothalamus
Where is oxytocin formed?
Oxytocin is formed by magnocellular neurons in the paraventricular nuclei
What increases the speed of acetylcholine production?
Choline acetyltransferase
How is choline transported across the nerve cell membrane?
Actively transported via high-affinity carrier system
How much ACTH is stored in vesicles?
Storage vesicles contain between 10000 and 12000 molecules of acetylcholine arranged in separate pools according to required availability.
What are gamma motor neurons?
Gamma motor neurons (GMNs) are lower motor neurons that maintain 1a afferent activity during contraction of the muscle. GMNs also regulate the gain of the muscle stretch reflex by adjusting the level of tension in the intrafusal muscle fibers of the stretch receptors, or muscle spindles. GMNs help to regulate muscle length and tone but do not detect the length of resting skeletal muscle.
Which neurotransmitter is found in the projection of the substantia nigra pars compacta to the striatum (caudate nucleus and striatum)?
Dopamine. Normally this results in inhibition of the globus pallidus, however in Parkinson’s disease the dopaminergic input to the putamen is lost, resulting in decreased inhibition and increased excitation of the subthalamic nucleus to the globus pallidus.
Where are the primary osmoreceptors found?
Anterior hypothalamus
What do neurons of the tectospinal tract control?
Neurons of the tectospinal tract control hand and eye movements
Which anatomical structure is critical for the arousal of the sleep–wake cycle?
The ascending reticular activating system is responsible for arousal and the state of consciousness by potentiating cortical function. It is the most critical component of maintaining a state of arousal.
What sensations do Type A nerve fibres transmit?
Touch, pain (fast), cold, proprioception
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