Please enable JavaScript.

Coggle requires JavaScript to display documents.

Nervous system - Coggle Diagram

- - - - info sent to integrator (brain)
        
        effector: processes activated by efferent nerves and hormone systems
        
        Compensatory response re-establishing homeostasis
- - - - a1: vein/ arteriole smooth muscle
        
        Contraction and stimulatory effect and higher affinity for NA
      - a2: endocrine pancreas
        
        inhibit insulin release (inhibitory effect) and higher affinity for NA
      - b1: heart
        
        increase rate and force and a stimulatory effect, also has similar affinity for Air/ NA
      - b2: airway smooth muscle
        
        relaxation and inhibitory effect and higher affinity for Adr
    - - Muscarinic acetylcholine
        
        named after agonist muscarine
        
        sound on effector cells innervated by parasympathetic branch
        
        blocked by atropine
      - Nicotinic acetylcholine
        
        named after the agonist nicotine
        
        receptors found on: postganglionic cell bodies and post synaptic membranes of skeletal muscle cells
- - - - motor (efferent = away from CNS)
        
        sympathetic (fight or flight)
        
        nerve fibres leave thoracic and lumbar regions of spinal cord
        
        sympathetic ganglia lie close to spinal cord and form a body known as sympathetic trunk
        
        short preganglionic fibres
        
        long post-ganglionic fibres
        
        ganglion closer to CNS
        
        Effect of increased sympathetic NS
        
        increased HR and CO (increased contractility of ventricle in presence of NA
        
        Constrict arteriole and venous smooth muscle = Increase BP
        
        Pupils dilate to let more light in
        
        respiratory airways open (relaxation of airway smooth muscle)
        
        breakdown of glycogen = more energy for muscles and brain
        
        increased sweating
        
        redistribute blood to skeletal muscles (during exercise)
        
        digestive and urinary activities shut down
        
        activate adrenal gland (adrenal medulla)
        
        release adrenaline and noradrenaline (catecholamines)
        
        adrenal gland activation
        
        preganglionic neuron (lumbar)
        
        chrmaffin cell (modified postganglionic neuron) = no axon cause it secretes Adr (80%)/ NA (20%) to bloodstream
        
        parasympathetic (rest or digest)
        
        nerve fibres leave from brain and sacral regions of spinal cord
        
        long preganglionic fibres
        
        short postganglionic fibres
        
        ganglion closer to effector organs
      - Sensory (afferent = towards CNS)
      - involuntary/ sensory signals are not perceived consciously
        
        heart
        
        smooth muscle of blood vessels
        
        visceral organs
        
        lungs
        
        intestine
        
        bladder
        
        glands
        
        genitalia
      - Two neutron chain
        
        Pre-ganglionic neuron
        
        cell body located in the CNS
        
        axon synapses with cell body of second neutrons, which lies in ganglion (cluster of neuronal cell bodies outside CNS)
        
        post-ganglionic neuron
        
        axon innervates the effector organ
        
        Advantages
        
        preganglionic neuron can synapse onto many postganglionic neurons
        
        can synapse onto both excitatory and inhibitory postganglionic neurons
        
        rapid, reflex effects on output
    - - motor (efferent = away from CNS)
        
        skeletal muscles
      - sensory (afferent - towards CNS)
  - - - salivary glands have both sympathetic and parasympathetic innervation but both are stimulatory for saliva secretion
- - - - Dive reflex
        
        Face cold and wet (breath hold) which stimulates mechanism- and thermoreceptors and consequently activates the parasympathetic system resulting in profound bradycardia
      - Cold shock response: immersion stimulates cutaneous cold receptors (whole body), which activates sympathetic system resulting in tachycardia
      - two opposing influences acting on heart simultaneously resulting in arrhythmias