Autonomic Nervous System and Basic Endocrinology Flashcards
The afferent nervous system is composed of______________
Sensory Neurons
The efferent nervous system is composed of the ______________ and ______________
Autonomic NS and Somatic NS
What is the function of the Autonomic Nervous System?
Maintenance of homeostasis
Most autonomic signals are ____________ consciously and not under ________ control
Not perceived
Voluntary control
Autonomic nerves consist of 2 neurons, the ____________ and ___________ neurons synapse in ganglia
Pre-ganglionic and Post-ganglionic
What are the advantages of a 2 neuron chains in the ANS?
- 1 Pre-ganglionic neuron can synapse onto many postganglionic neurons
- 1 Pre-ganglionic neuron can synapse onto both excitatory and inhibitory neurons
- Information from sensory axons can act before reaching the CNS
Sympathetic nerves have a _____ preganglionic neuron and a _____ postganglionic neuron.
Short
Long
Sympathetic nerves exit the CNS in the _______ and _______ regions of the spine
Thoracic and Lumbar regions
Due to the short length of the ___________ neuron, the ganglia of the sympathetic nerves form a body close to the spinal cord called the _______________
Pre-ganglionic
Sympathetic trunk
What does the sympathetic trunk allow sympathetic neurons to do?
“Talk” to each other
Parasympathetic nerves have ______ preganglionic neurons and _____ postganglionic neurons
Long
Short
Parasympathetic nerves exit the ______ and _______ region of the spine
Brain
Sacral
Parasympathetic and Sympathetic nerves generally exert _________ effect on an organ
An opposite
Sympathetic stimulation causes heart rate and cardiac output to ________.
Increase
In the presence of noradrenaline the contractility of the ventricle ______ which causes cardiac output to ______.
Increase, Increase
What are the effects of increased Sympathetic NS activation?
Increased Heart Rate and CO
Constriction of arteriole and venous smooth muscle
Dilation of pupils
Relaxation of smooth muscle in the airways
Breakdown of Glycogen and Fat stores
Increased sweating
Discuss the redistribution of blood flow when the Sympathetic NS is activated.
- At rest 15-20% of blood flow goes to the skeletal muscles
- When sympathetics are stimulated blood vessels in the skeletal muscles dilate
- The blood vessels in the kidney, stomach, intestines and liver constrict
- This causes 80-85% of blood flow to go to the skeletal muscles during activity
Sympathetic NS activity stimulates the __________ to release ________ into the blood which reinforces sympathetic actions.
Adrenal Medulla
Adrenaline
Do the Parasympathetic and Sympathetic nervous systems always have opposite effects?
No, for example in the salivary glands they both stimulate secretion of saliva
What is the Dive reflex?
When the face is submerged in water, mechanoreceptors and thermoreceptors activate the parasympathetics resulting in pronounced Bradycardia (Abnormally slow HR)
What is the Cold Shock response?
Submersion in cold water will stimulate cutaneous cold receptors to activate the sympathetic NS resulting in pronounced Tachycardia (Abnormally fast HR)
With respect to the ANS, what is the function of the hypothalamus?
To integrate information it receives into a coherent pattern of autonomic responses
What is the major neurotransmitter for all pre-ganglionic-post-ganglionic synapses?
Acetylcholine
What does Cholinergic mean?
The neuron releases Acetylcholine at its synapse
What does Adrenergic mean?
The neuron releases Noradrenaline at its synapse
In sympathetic pathways, the pre-ganglionic neuron is ____________ and the post-ganglionic is ____________
Cholinergic
Adrenergic