Very Hard Flashcards
where is PNS and SNS
PNS is the cranial and sacral SNS is the lumbar and thoracic
Electrical stimulation of postganglionic parasymaethic fibre to vessels
Acetylcholine and nitric oxide produce a rapid relaxation
The vasoactive intestinal peptide can produce a slow delayed response
Electrical stimulation of postganglionic sympathetic fibre to vessel
ATP produces a fast contraction in the smooth muscle
Noradrenaline produces a moderately fast response
Neuropeptide Y produces a slow response
Noradrenaline and adrenaline
Noradrenaline and adrenaline are endogenous agonist of a family of adrenoreceptors that are GPCRS
A adrenoceptors -> noradrenline -> adrenaline -> isoprenaline
B adrenoreceptors -> isoprenaline -> adrenaline -> noradrenaline
what is motor neurons
Motor neurons - cell bodies in the cerbeal cortex and their axons extend down the spine
what is a lower motor neuron
Lower motor neuron is neuron synapses are directly responsible for stimulating contraction which allows the generation of force that can lead
what is extrafusal and intrafusal
extrafusal is a motorneuron and is the bulk of skeletal muscle fibres
Intrafusal is by y motorneuron and is the remaining speclaised fibres
Stretch Myotatic Reflex
muscle stretch and group 1a afferent fibres in the muscle spindle start firing
these synapses on the motorneuron same muscle from which the group 1a afferent relayed the sensory information a motorneuron indcue contraction of skeletal muscle and the muscle returns to resting and firing la decrease
Inverse Myotatic Reflex
muscle contracts, extrafusal fibres shorten and stimulate golgi tendon
group 1b afferent start firing and send sensory information to inhibitory interneurons they synapse on the spinal cord
inhibitory interneuron synapse on the a motorneuron muscle returns tot he resting length and firing frequency of group 1b decreases
synergist muscle also relax and antagonist muscle contracts
Flexion withdrawl reflex
The leg that feels the pain the reflex inhibits in reflex inhibits the spinal cord extensor and estimates flexor
the opposite leg reflex stimulates spinal cord the motor neurons to extensor muscle and inhibits the motor neurons to the flexor
Cardiopulmonary Baroreceptors
veno arterial stretch mechanoreceptors in pinkish bit
baroreceptors in the aorta
Non-myelinated mechanoreceptors below bit
Chemoreceptors left side
Not all baroreceptors are created equal
Carotid sinus baroreceptors are more sensitive
the cause greater changes in blood pressure that aortic arch baroreceptors
Long-term control differs
Long-term control differs
Relies on the control of blood volume
Think control of cardiac output by Starling’s law of the heart
Involves kidney