ANS - Lecture 4 Flashcards
In ANS, 2 neurons that connect CNS to the target neuron
preganglionic neuron and postganglionic neuron
Where pre and post ganglionic neuron synapse.
In the autonomic ganglia
What is an autonomic ganglia
collection of dendrites, cell bodies, synapses in the PNS. There are many
SS (symp. system) : where cell body of pregang. neuron and where it synapses/where axon reaches out
In the spinal cord, axon reaches out just outside the spinal cord and synapses with postgang. neuron
SS postgang. neuron length
long (reaches out from near spinal cord to the organ)
SS : Synapse 1 is excit. or inhib.
excitatory
SS : Synapse 1 neurotrans. and receptor on the postgang. cell
ACh. nACh receptors
SS : Synapse 2 (on the target tissue) excit. or inhib.
Can be either. Depends on target tissue
SS : Synapse 2 neurotransm.
Norepinephrine (neuromodulator btw)
SS : Norepinephrine effect on heart and on bronchial tubes
Heart : Faster heartbeat
Bronchial tubes : Smooth muscle relaxes (not activating), tubes expand
SS : Synapse 2 receptors on target organ (2), difference + type of receptor
alpha-adrenergic receptors or beta-adrenergic receptors
similar structure, pharmacologically diff. Metabotropic receptors
PSS (parasymp. system) : Where cell body of preganglionic neuron is
Brain stem (most of them) and sacral part of the spinal cord
PSS : pregang. neuron length
long, extends almost all the way to target organ
PSS : postgang. neuron length
short, short axons directly into target tissue
PSS : Synapse 1 excit. or inhib. + neurotransm. and receptor
excitatory (just like SS synpase 1). ACh, nACh receptors
PSS : Synapse 2 excit or inhib. + neurotransm + receptors
Can be either excit. or inhib. ACh, muscarinic ACh receptors
muscarinic ACh receptors what type of receptor
Metabotropic receptors
PSS : ACh effect on heart and on bronchial tubes
Heart : Slower heartbeat
Bronchial tubes : Causes contractions of smooth muscle (activating)
Ultimately, what is the diff. between SS and PSS
Pharmalogical differences that neurotransmitters have on target organs (how they affect target cells)
SS : Distribution of preganglionic neurons
Originate from thoracic and lumbar parts of spinal cord
SS : Specific name of where Synapse 1 takes place + name of these when aligned
SS : Synapse 1 in sympathetic ganglia. Aligned sympathetic ganglia along spinal cord = sympathetic trunks
Most important nerve in the PSS (main PS output nerve)
Vagus nerve
Where vagus nerve originates and where it goes (4)
In brainstem (vagus nerve is a cranial nerve). Goes to heart, digestive tract, bronchi and gallbladder)
ANS response to sensory inputs + info relay with CNS (4 steps)
1) Sensory components of ANS collect info
2) Info sent to CNS
3) CNS decides what to do (unconscious)
4) ANS reacts based on CNS order
4 ways to carry info (afferents) to CNS (from ANS)
Vagus nerve (output and input back to CNS - brainstem), glossopharyngeal nerve, facial nerves, pain afferents around body
Brainstem importance in ANS (2)
integrates autonomic inputs and regulates autonomic outputs
Most important region of the brainstem where integration regulation of autonomic inputs/outputs takes place
A brainstem nuclei called the nucleus of the solitary tract
What is a nucleus in neuroanatomy
Collection of neurons/synapses in the CNS
Sensory inputs don’t stop at brainstem. 3 higher brain centers involved in homeostasis
Hypothalamus
Amygdala
Limbic cortex
What limbic cortex is and does
Part of cerebral cortex that connects cognitive states (ex. being scared) to physiological responses (faster heartbeat)
What regulates autonomic reflexes in the brainstem
Higher brain centers
Main higher brain center that regulates autonomic responses in the brain stem + general function
Hypothalamus. Maintains homeostasis and regulates 3 diff. systems
Hypothalamus job in general
Maintains homestasis, regulates and coordinates 3 diff. systems
3 different systems coordinated and regulated by the hypothalamus
ANS, endocrine system and connection between cognition/behaviour and physiological states
How hypothalamus regulates/ coords ANS
Through connections between the hypothalamus and the brainstem
How hypothalamus regulates/coords endocrine system
Connections between the hypothalamus and the pituitary gland
What endocrine system does
Release various hormones in bloodstream
How hypothalamus connects cognition/behaviour and physiological states
Through connections with the limbic (cerebral) cortex
Hypothalamus action when we’re cold (ex. of coord/regul. of the 3 systems)
- Communicates to ANS through brainstem to start shivering - raise body T
- Comm. to endocrine syst (pituitary gland) to release hormones that raise metabolism.
- Comm. to limbic (cereb.) cortex to motivate to get a sweater
5 phgy needs regulated by Hypothalamus
BP, T, energy metabolism, reproduction, emergency responses to stress
How the hypothalamus ‘‘regulates’’ (based on what)
Based on biological set points
Where hypothalamus receives sensory inputs from (2)
- Sensory neurons in the body
2. Sensory neurons within the hypothalamus
How ANS links physiological states to emotion and cognitive states
Through connection with hypothalamus, which is connected to the limbic system.
Region of the brain where limbic system is found
Ventromedial prefrontal cortex
Relay of information (4 structures) that links phgy states to emotion/cognitive states
ANS HypothalamusAmygdalaVentromedial prefrontal cortex
Amygdala role (3 things to note)
Emotions
Links what body does and how we feel about it
Important in context of fear
How many amygdalas
2 amygdalas on each side of the brain
2 possible consequences of lesions to an amygdala
1) No phgy/emotional responses to pictures that should cause strong reactions
2) Failure to remember emotionally charged picture better than emotionally neutral ones
Frequency of individuals with both amygdalas lost.
Very rare
