Mairead - ANS Integration, Reflexes and Tone Flashcards
What happens if an organ is innervated by both the sympathetic and parasympathetic division?
(2)
The divisions might have opposing effects e.g. in the heart
Or they might have complementary effects e.g. in reproduction
Which autonomic division are the arteries and veins innervated by?
Most are innervated by the sympathetic division
What is autonomic tone?
The resting level of spontaneous activity shown by the ANS neurons in the absence of stimuli
Write a note on the ANS and the heart
(4)
Has both sympathetic and parasympathetic innervation
The sympathetic increases heart function (HR and SV)
The parasympathetic decreases heart function (mostly just HR)
At rest both are active but parasympathetic is dominant
Write a note on the blood vessels and the ANS
(2)
Blood vessels are mainly innervated by sympathetic nerves
Control of blood flow and blood pressure by increasing/decreasing sympathetic tone
What is integration?
Sensory receptors, sensory nerves, nervous interpretation, motor nerves and an effector all in a circuit called a reflex
In the somatic NS, what does reflex speed depend on?
Giving examples (3)
The length of the circuit
Spinal reflexes are short and quick and have few synapses
Brain reflexes are long and slower and usually have many sensory inputs
List the steps to a reflex arc
(5)
- Arrival of stimulus and activation of receptor
- Activation of a sensory neuron
- Information processing in CNS
- Activation of a motor neuron
- Response by effector
Where can integration/information processing take place in the ANS?
In the ganglia
In the CNS
Give a specific type of ganglia where information processing can take place
Parasympathetic ganglia
Give some locations in the CNS where integration can take place.
Also give the type of integration that occurs.
(3)
In the spinal cord (subconscious)
In the brainstem (subconscious)
In the hypothalamus (both conscious and subconscious elements)
What is the blood pressure reflex called?
Baroreceptor reflex
What happens to the Baroreceptor reflex when the SNS activity increases and the PSNS activity decreases?
There is an increase in cardiac output and vasoconstriction which increases blood pressure
What happens to the Baroreceptor reflex when the PSNS activity increases and the SNS activity decreases?
There is a decrease in cardiac output and vasodilation which reduces blood pressure
Define negative feedback
(2)
A corrective mechanism that opposes or negates a variation from normal limits
A stimulus triggers a response, then the response reduces the strength of the stimulus