How nervous tissue is involved in body function regulation ?
-Every neuron has two core function :
1-impulsation cunduct : impulses pass by nerves between the CNS and prephral organs thats is the essence of the local currents irradiation on the membrane neurons
2- impulsation processing : during 1 second of the spinal cord receives the amount of information equal to information volume which is contained in some greatest library and its received it in form of AP
What is the basic functional units of a neuron and their value
1- receptor: its an independent part of neuron , its serves for perception of irritation
2- Dendrite : its serves for impulsion conduct from a receptor to a neuron body
3- neuron body : as any cell body carries out the metabolic reactions to provide vital activity
4-axonal colliculus : the special part of axonal colliculus the membrane has the lowest threshold to an axonal colliculus that subthreahold impulses from receptor and dendrites pass
5- Axon : conducts impulsion from neuron body to synapse
6- synaptic patch : transmission function
What is the purpose Of CNS ?
Is implementation of the nervous regulation of peripheral organs
Nervous regulation is carried out on ?
Its carried out on the basis of reflexes
Who is the first interdouce the concept of reflex arc ?
Rene decartes 1596-1650 france philosopher
Who is the first develop the modern idea of reflex arc ?
Ivan mihailovich 1829-1905
Russian physiologist
What is the definition of reflex arc ?
And give an example
A reflex is a response of an organism mediated through the central nervous system
Ex: arm withdrawal upon finger
What is the bruise ( hematoma)?
Its also reaction to mechanical action on subcutaneous tissue, and CNS doesn’t take part in it
What is the morpho-functional substrate of reflex ?
Its reflex arc , and only an arc
- a reflex can be realized only when a reflex arc is available and through it
And its consist of 5 elements
What is the 5 elements of reflex arc ?
1- receptor 2-afferent neuron 3- central neuron 4- motor element 5-effector
Explain the first element of reflex arc ?
-The first element is A receptor
Receptor of reflex arc called receptive field
- receptive field : is set of one type receptor activation of which causes implementation of a particular reflex
Explain the 2nd element of reflex arc
Its a sensitive or afferent or cerebriptal element
- its consist of dendrite ( long ) and axon ( short )
- an afferent neuron conducts the impulse from receptive field to the central nervous system
-anatomical charectrastic :
The totality of nighboured dendrites of sensitive neurons forms sensory nerve , the totality of nighboured bodies of neurons form the prevertbral gangelia , the totality of the neighboured axons forms the posterior cerbrospinal root .
- was decicrived in Bell-Magendie experiment.
Explain the 3rd element of reflex arc
- its central element : its represented by one or multiple intercalary neurons , thats is why this element is often called intercalary element, its located only in the central nervous system
- and its perform 4 function :
1- its connect the afferent and motor components
2-its connects different reflex arc within the limits of one cns part
3-its connect of reflex arcs of different division of CNS ex spinal cord and brain
4: its processes information - body of the intercalary neuron form the post horn of the spinal cord
Explain the 4th element of reflex arc
- its the motor element or efferent or cerebrifugal one ) : its represented by a motor neuron
- motor neuron: which regulate the activity of skeletal muscles from anterior horn of the spinal cord
- motor neuron: which regulate the internal organ from lateral horn of the spinal cord
- motor neuron functions is the formation of a reflex response
Explain the 5th element of spinal cord
- its an effector : it always lies only in the periphery part ( out of the cns ) it can be either muscle or glandular
- the function of an effector is performing the feed back response
How reflexes carried out ?
The reflex can be carried out only when the integrity of all reflex arc is preserved
( anatomical and physiological integrity
What is the classification of reflexes and reflexs arcs
1- by receptor : its not exist bcs sensitive neuron doesn’t process information its only pass impulses
2- by localisation of central part of reflex arc : here there is several classification
1- by level localzation of an intercalary neuron in the CNS , Ex spinal cord , bases of brain etc
2- by presence /absence of an intercalary neuron, absolutely all centres of reflex have several intercalary neurons there is only one group have no intercalary called tendon reflex
3-classfication by effector: here is also two type of classification
1- classification by working organ
2- somatic reflex and autonmic vegtative reflexs
4- by purposefulness
5 - unconditional reflexes: those are implemented without our weariness
6-conditional reflexs
