Because the thing about vascular tone,
Is not just more or less vasoconstriction,
When tone is reduced,
This is often produced,
By the active process of vasodilatation.
That beta-adrenoceptors mediate dilatation.
Does not mean that they’re inhibitory.
Just like the rest,
They’re linked to G alpha S,
So result in more cyclic AMP.
Trapped in the freshly laid osteoid,
Some osteoblasts become osteocytes.
There they sense load,
Such that remodelling is slowed,
In the immobile and also spaceflight.
So that’s an end of this year’s daylight savings.
It is not just an extra hour in bed.
Disruption ensues,
To your Zeitgeber cues,
Increasing risk from chronic diseases instead.
Smooth muscle is the best type of muscle,
For all of the roles that it plays.
From controlling blood flow,
To when you must go,
And your focus, peristalsis and airways.
Isometric or isotonic contractions,
Are used for muscle experimenting.
Isometric depends,
On being secured at both ends,
And where tension’s developed but not shortening.
The sacroplasmic reticulum,
Is a skeletal muscle calcium store.
Following depolarisation,
The T-tubule migration,
Stimulates ryanodine receptors and the outpour.
Phase 4 of Valsalva Manoeuvre,
Occurs when the breath hold’s released.
The increased venous return,
Stimulates the vagus in turn,
Causing the heart rate to decrease.
The humble Valsalva manoeuvre,
Can test autonomic control.
The quickened pulse it reflects,
The baroreceptor reflex,
That’s triggered by the subject’s breath hold.
With colds and with flu comes a fever,
As pyrogens act from within.
Your hypothalamus is told,
That you’re actually cold,
So physiological thermogenesis kicks in.
Once acetylcholine binds to its receptor,
And its target cell signal transduced.
The cholinesterase,
Ensure it never outstays,
And what’s left in the cleft is reduced.
Ringers indeed contains potassium,
But its concentration is relatively low.
Its volume of distribution,
Means no increased concentration,
As study on study now show.
Lactate ringers in hyperkalaemia,
Was once contraindicated.
As potassium it contains,
A fear of adding fuel to the flames,
So saline was preferred option instead.
Intermittent claudication,
A hallmark of arterial disease.
From the pain you imply,
Demand can’t be met by supply,
But if you stop for a rest it will ease.
The thing about catecholamines,
Is their rank order of potency.
Adrenaline it’s true,
Binds both alpha and beta too,
But it’s beta it’ll bind preferentially.
Contusion or trauma to the testicles,
Can be felt in the lower abdomen.
That pain is referred,
By the genitofemoral nerve,
Which arises from the spinal lumbar region.
I used to have an excellent French phrase book full of helpful phrases such as this.
It was called C’est Pour Mon Crapaud (it’s for my toad)
Interactions between pure actin and myosin,
Aren’t regulated but actually the norm.
But on filaments that are thin,
The tropomyosin,
Regulates when cross bridges will form.
The phenomenon of the pudding stomach,
To squeeze in dessert even though you’re full.
Having dined out on salty,
And a helping of umami,
Something sweet offers a tasty new pull.
As temperatures climb in a heatwave,
And you look for some protection.
One way to keep cool,
Put your feet in a basin or pool,
As it increases heat loss by convection.
A crucial survival mechanism,
Is the flexor withdrawal reflex.
Noxious sensory information,
Has rapid spinal integration,
And sharp withdrawal avoids harmful effects.
The joys of small vessel myography,
When you don’t know whether to cry or to laugh.
When the vessel’s prepared,
With the upmost of care,
Only to disappear, without trace, in the bath.
An osteoblast will lay down the osteoid,
Within this freshly laid bone some remain.
That’s not the end of its plight,
It becomes an osteocyte,
And relays signals of bone stress and strain.
The ventricular action potential,
Has a long phase of calcium plateau.
Because it’s still depolarised,
The heart can’t be tetanised,
As the tension on its way to zero.
Secondary hyperparathyroidism,
Is a feature of chronic kidney disease.
With the tissue depletion,
There’s less 1 alpha hydroxylation,
Resulting in vitamin D deficiencies.
BNP is a marker of heart failure,
That suggests excess fluid retention.
Since the Frank-Starling curve,
Says stroke volume’s preserved,
By a RAS-induced volume expansion.
Filtration along a capillary,
Is not reversed at the venous ends.
In the interstitium’s place,
Sits the subglycocalyx space,
That’s the gradient upon which filtration depends.
A protection for cerebral perfusion,
Alpha adrenoceptors are relatively rare.
So when sympathetic activation,
Produces peripheral constriction,
The cerebral circulation is relatively spared.
In the principal cells of the kidney,
Are important for sodium reabsorption.
But this comes at a cost,
That is potassium loss,
So you can’t control either in isolation.
The mechanism of reactive hyperaemia,
Increased flow after a drop in perfusion.
As flow increase from its nadir,
There’s an increase in shear,
The results in more vasodilation.
