Lecture 19- Autonomic nervous system I Flashcards Preview

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What are the population data for cardiovascular disease?

• Total global deaths – 16.7 million

– Coronary heart disease – 7.2 m

– Stroke – 5.5 m

– Hypertensive heart disease – 0.9 m

– Inflammatory heart disease – 0.4 m

– Rheumatic heart disease – 0.3 m

– Other multi causal (incl. peripheral vascular disease) – 0.9 m

• Directly attributable to high blood pressure

– 49% for coronary heart disease – 62% for stroke

-hypertension is high blood pressure


What is the disease burden of cardiovascular disease?

-% of disability adjusted life years -the highest! -males 15 y. o. and above


What is the relationship between systolic blood pressure and CV disease (cardiovascular)?

-The risk of CV disease increases with every increase in systolic blood pressure


What is the definition of high blood pressure?

-Currently the definition of high blood pressure is >140/>90 (systolic/diastolic)


Blood pressure increases with age except when:

- NaCl intake is low - Physical activity is high -Obesity is absent


How many people have high blood pressure?

- In most countries (developing and developed) - 30% of adults have high blood pressure - 50‐60% more would have better health is BP were lowered.


How can you prevent the increase in high blood pressure?

-Increased physical activity -Maintenance of ideal body weight -Better diet (fruit and vegetable intake)


Are most organs in the body innervated by the autonomic nervous system?

-most organs of the body receive a level of innervation from the autonomic nervous system -from your pupils to your reproduction -most functions of the body comes from the autonomic nervous system


What is the two neuron chain involved in the autonomic control (sympathetic)?

-the neurons that control the sympathetic activity to the organs are part of a two neuron chain, preganglionic neurons exist in the spinal cord, have a short projection to the sympathetic chain where synapse to the post ganglionic neurons that then go to the target tissue


What effect does sympathetic innervation have on blood vessels?

-projection of the sympathetic neuron onto the blood vessel causes constrictions -so increase in neural stimulation causes constriction -increase in peripheral resistance -that is how it can change blood pressure


What effect does the sympathetic innervation have on the pacemaker cells of the heart?

-increases heart rate (tachycardia)


What is the sympathetic nervous system like for controlling the blood pressure?

-sit at a midrange -can increase and decrease vascular tone and heart rate


How does the parasympathetic nervous system affect the pacemaker cells of the heart?

-parasympathetic also projects to the pacemaker cells -this decreases the heart rate


What are the characteristics of a somatic nervous system neuron?

-cholinergic neuron, innervating skeletal muscle -projects from the CNS to the muscle, it releases acetylcholine there onto N1 nicotinic acetylcholine receptor to cause contraction


What are the characteristics of an autonomic nervous system neuron? (pre ganglionic)

-also cholinergic -both sympathetic and parasympathetics preganglionic neurons use acetylcholine on N2 nicotinic acetylcholine receptor


What are the characteristics of the postganglionic neurons in the parasympathetic nervous system?

-the postganglionic in parasympathetic use acetylcholine onto M (muscarinic acetylcholine receptor), metabotropic receptors! -they are short, usually in the tissue they are innervating


What are the characteristics of the postganglionic neurons in the sympathetic nervous system?

-the postganglionic in sympathetic use noradrenaline (onto alpha and beta adrenoergicg receptors)


What is the special case of the sympathetic nervous system?

-special components: adrenal medulla, rather than postganglionic neuron have chromaffin cells that release adrenalin into the environment


Where are the sympathetic preganglionic neurons located?

-in the spinal cord

-thoracic and upper lumbar part

-in the butterfly (have the gray matter)

-in the lateral horn, called the intermediolateral cell column (IML)

-these are motor neurons so they project through the ventral horn


What is the anatomy of the pre and postganglionic neurons and the sympathetic chain?

-go through the visceral efferent fibre

 -then project through the white communicating ramus (white= myelinated)

-pre-ganglionic neurons are myelinated, white and use ACh so fast fast fast

-then synapse onto postganglionic neurons that project via gray communicating ramus (unmyelinated), slow conducting

-the beads are the ganglia (collections of postganglionic neuron cell bodies)

-called the sympathetic chain (the beads)


What is the prevertebral chain?

-another group of ganglia, along the midline, viscera -provide mainly the intestines, -prevertebral and paravertebral


What is the connection of the sympathetic postganglion neuron and the target tissue?

-postganglionic neuron projects to the target, the sympathetic ones have long projections to the target tissue (unlike parasympathetic) -doesn't have a direct connection (synaptic) -has multiple vesicle release sites -throughout long distances of the axon, each can be the release site and can affect several muscles -diffuse network of terminals


How can the sympathetic nervous system control blood flow?

-level of constriction and tone of blood vessels at any time

-can increase the activity get constriction or dilation


Does the output have tonic output?



What is this?

-second from the bottom: 2nd thoracic segment, pre-ganglionic sympathetic neuron 

-the 3rd from the bottom is blood pressure

-measuring temperature of the spinal cord (the most bottom one)

-axon signals are temperature dependent (the channels), if too cold you stop the creation and conduction of APs

-if temperature goes down the neuron slows down activity and then stops


What is this?

-upper line, normal person -below, person with a lesion below thoracic and lumbar -when have lesion, you lose the sympathetic and parasympatehtic activity!


Is there ongoing activity in sympathetic nerves supplying the musculature?

-yes -this is dependent on drive from the centers above the spinal cord -some sort of drive above, to maintain the blood pressure -excitatory input that maintains the tonic


How can a person with a high level spinal lesion survive?

-because blood pressure is pulled up by the hormones not the neurons (from kidney, angiotensin) -the regulation by the hormones is less specific, not as fine tuned


Describe the first part of this:

-have the preganglionic neurons in the spinal cord and they have effect on the primary motor neurons that then target the muscle

-know that something needs to be controlling them


What is this?

-recording of a blood pressure through finger

-exercise at different levels

-with increase in activity, increase in systolic blood pressure (less in diastolic) and increase in heart rate