basic medical sciences

All about the blood pressure; my personal impression

The blood pressure is the force exerted by the blood on the wall of the blood vessel;
P = F/A
Where P is the pressure; F is the force and A is the area

all about the blood pressure figure 1Figure 1: The blood pressure is the force exerted by the blood on the wall of the blood vessel.

In other words:
The blood inside the blood vessel exerts a force that tends to keep the blood vessel open, i.e. not collapsed.

Therefore, the blood vessel itself plays an important role in determining the blood pressure, because when the blood vessel is more malleable, i.e. it does not much resist the force exerted by the blood, the resulting blood pressure is less for the same amount of force ‘F’ as compared to the situation when the blood vessel is stiff.

To sum up, the blood pressure is the outcome of two main and interacting parameters:
1- the force exerted by the blood on the vessel wall to keep it open and
2- the blood vessel malleability or distensibility, i.e. malleable or stiff.

The blood pressure is an important parameter of the blood circulation condition and is measured conveniently by an indirect method using an apparatus called sphygmomanometer.

This method relies on detecting sounds caused by blood flow turbulence during blood vessel compression, where the first appearance of sound denotes the highest level of blood pressure, i.e. systolic blood pressure, and the disappearance of sound denotes the lowest level, i.e. diastolic blood pressure.

The following diagram shows this indirect measurement of blood pressure.

all about the blood pressure figure 2Figure 2: The indirect measurement of blood pressure using a sphygmomanometer.

The blood pressure alternates between a maximum level (systolic) and a minimum level (diastolic) with a gradient slope in between!

Can the behaviour of blood pressure be approximated to the behaviour of regular wave?

all about the blood pressure figure 3Figure 3: Can the behaviour of blood pressure be approximated to the behaviour of regular wave?

Critique/ evaluation of the blood pressure as a conventional parameter for assessing blood circulation condition.

The blood pressure is dynamic. It changes continuously to reflect many physiological processes and conditions.

However, such changes in blood pressure are kept within certain range that can vary (significantly) from one person to another; and still considered normal or physiological.

The human body may be described in three different conditions of activity or stress; considering both physical and emotional aspects:
1- Relaxing
2- Working or exercising
3- Demanding stress

Because the blood vessel is living and viable, it can respond to dozen(s) of signals and/or signal combinations.
Examples of signals/ conditions:
1- Circulating chemical/ biological molecules.
2- Cold/ hot
3- Full stomach; full rectum
4- Thirst; hunger; smells; oxygen
5- Mood condition; accept/refuse feeling

And as such the blood pressure changes over time and condition-wise to meet the body’s need of sufficient and effective tissue supply of nutrients and oxygen and to eliminate waste products and CO2.

Why should the blood pressure be changing or dynamic?
The gross changes and sensible phenomena can find their origin in basically working subtle changes.

There could be subtle, i.e. very fine, changes in blood pressure that are needed for proper and smooth blood flow within the blood vessel.
These may be due to the continuous (breathing-like) changes in vessel wall diameter (mainly small blood vessels) that would help stirring of blood into a largely homogenous mixture. Otherwise, the blood in the vessels would be quite randomly fractionable.

all about the blood pressure figure 4Figure 4: Subtle changes in small blood vessel diameter (wall contraction) that would help blood mixture stirring or mixing. The figure shows one cycle (intrinsic mini-hearts).

Here, we may appreciate the condition of the blood vessel lining being smooth to hep both quiet blood flow and blood mixing.

The blood pressure is dynamic and changes to meet the needs of the body according to each situation.

The blood pressure changes are kept within a range that may differ significantly from one person to another and would be considered normal or physiological for that person.

The blood pressure is the outcome of a few other parameters, e.g.:
1- blood kinetic energy
2- blood vessel condition; malleable: health =/ stiff; relaxed =/ contracted and
3- blood volume
which in turn are influenced by body condition.

Interpretation and handling of blood pressure.
General concept (s):
1. The blood pressure knows what to do. It corrects itself by itself. However, it may need some help.
2. Gross changes in blood pressure can be understood and are in the most part temporary and harmless.
3. Low blood pressure and high blood pressure could be considered two faces of one coin as they share much in their conservative handling.
4. In the handling and evaluation of blood pressure, every person should know his/her unique normal.
5. The blood pressure reading should be interpreted context-wise, and not for its own.
6. Gross blood pressure changes may be
1) constitutional and need only conservative handling;
2) constitutional and need both conservative and medical handling;
3) causal and need to know and handle the cause.

Conservative handing of blood pressure.

There could be a paradigm for both low and high blood pressure.
Conservatively, low and high blood pressure are handled in the same way, because this would aim to help the body itself to correct itself through only filling the gaps.

First: enumerate the gaps that would be relevant and then order them according to their weight/influence/contribution to the present condition.

all about the blood pressure figure 5Figure 5: Example of factor chart analysis.

Second: choose the gap filling order in/according to your accurate intuition, e.g. incremental correction model that is body energy-wise correct. For the above factor chart analysis, the filling order could be:
To sit on toilet (3) — to rest for a while/walk for a while (1) — to drink sugary water or sugary juice (2) — to do gentle exercise (4) — to rest/lie down for some time if you think so (3’).

This could be a matter of trial and error, i.e. learning process. And one can know how things would be accurate and correct for him/her personally.

Incremental and logic correction is needed to achieve a smooth and satisfactory result.

Medical handling of blood pressure.

all about the blood pressure figure 6Figure 6: Blood pressure fluctuates normally according to body activity and/or day time.


all about the blood pressure figure 7Figure 7: Arbitrary blood pressure value (line) without antihypertensive drug (a) and with drug (b). A model suggested for drug monotherapy, i.e. one drug taken once daily. Notice, the dipping in blood pressure after the drug dose (arrow).


all about the blood pressure figure 8Figure 8: Arbitrary blood pressure value (line) without medication (a), or with only one medication (b), and with another medication (c). in the double or more (multi-)therapy model, one medication is suggested to produce a background blood pressure lowering (here drug b; e.g.) which seems to be more durable and more effective, while other drug(s) produce more lowering of blood pressure for shorter time; i.e. the B.p. lowering effect of the helping drug(s) may not be fully justified without considering the effect of the principal drug that produces the background BP lowering, i.e. new B.p. base line.

For further discussion and perspectives:
1- role of each B.P. variable on either systolic or diastolic blood pressure.
B.P variable           Systolic B.P.           Diastolic B.P.
Blood vessel wall        ↑↑ ?                          ↑?
Blood kinetic energy  ↑↑ ?                         ↑↑ ?
Blood volume               ↑?                            ↑↑ ?
Heart rate                     ↑↑ ?                         ↑↑ ?

2- what are the considerations needed when assessing blood circulation condition using the blood pressure?
3- what could be the original parameter of blood circulation (Ɛ) that the blood pressure serve to shadow?
4- could be there measurable parameters/variables other than blood pressure that can serve to assess blood circulation condition?
5- molecular markers for assessing blood circulation; perspective of blood circulation assessment.

basic medical sciences

Human physiology – a continuum of balance

Human physiology – a continuum of balance

Physiology is the science concerned with the body functions and its underlying mechanisms. It is one of the basic medical sciences including anatomy, histology, pathology, microbiology and pharmacology. The advantage that physiology could have compared to other basic sciences is that it goes hand in hand with body function, regulation and disturbance. Anyhow, it could be agreed upon that separation of basic sciences may apply only for simplification and study purposes rather than for real and working performances.

Sticking to basics and practical problems it may be quite obvious that medical staff including physicians study physiology in order to care of sick individuals especially those in serious conditions that need timely and efficient management. In this respect the appreciation and mastering of basic body functions that normally work dependent on each other like and for a continuum balance would make the difference in defining certain outcome. That is why studying physiology as a basic medical study course should be precise, focused and appropriately modular. In other words, the objective view and appreciation of the dynamic and interconnected body functions in a working and easily perceived biophysical model could be that what is conceived in memory and helps in health problem solving apart from many apparently irrelevant and superfluous details.

A well known medical term is homeostasis which would mean the fundamental criterion of keeping the body internal environment within a normal range of biochemical and biophysical values in a dynamic steady state. Therefore, homeostasis concludes the ultimate goal of all physiological processes and describes biological and living systems as comprehensively and elegantly as possible. Behind the coulisses of homeostasis one might see several body organs and tissues, each assigned to a certain function, that work dependently in harmony. Again, one may prefer to reduce those functions to their underlying biochemical and biophysical component forces that could be approximated to a couple of laws or mathematical equations. Such preference could be based on both personal views and study or experimental facilities and should accordingly influence medical case management in terms of time, technical issues, costs and ultimately outcome.

As it could be understood from the discussion above, studying physiology outside its pathophysiological frame would be a matter of time waste. This is simply because investigating disease is an essential drive and clue as well to understand a certain normal physiological process (recall the purpose of physiology as basic medical course mentioned earlier in the essay). Accordingly, it may be very rational to establish a general check list or scheme when discussing a given physiological or pathophysiologic question. Such a check list can include body temperature, pulse, blood pressure, pH, electrolytes, general condition, mood, and any emergent complaint. To conclude this essay on human physiology, it signifies the importance of modular systematic physiology and systematic review of its findings and examination.

basic medical sciences

The clapper and the intonation room, a hypothetical medical context

the clapper and the intonation room
In medicine it is usually reasonable to consider the clapper (the heart) together with its intonation room (the lungs). The cardiorespiratory cycle may, therefore, be considered one entity and should be split only for simplicity. The academic question in this point is how the two phases of respiration are orchestrated with the two phases of cardiac cycle, from one side, and with the concurrent gas/metabolite exchanges in the lungs and tissues, from the other side. Although I did not yet look for an authenticated answer, I would like to present in this text a hypothetical model based on common sense and the concept of lung compliance.

The clapper has got in intrinsic rhythmicity and alternates between contraction (systole) and relaxation (diastole). Although the serial 4- station pass of blood (the cardiac cycle) would be very exciting, i.e. right atrium > right ventricle > left atrium (through the lungs) > left ventricle (to systemic circulation), and might be apparently conforming with the site of SAN and AVN and the path of nerve impulse conduction, a 2- station pass may be described in text books, in which model the right and left hearts are switched in parallel. Yet, to fulfill my scientific fantasy, even a minor right to left lag might be present.

As the right ventricle contracts blood goes to the lungs (through the pulmonary arteries), and the lungs increase minimally in volume due to elastic recoil of the pulmonary arteries. Meanwhile, the volume of the lungs may be increased by inspiration. Such an increase in lung volume by inspiration is not factually essential for right ventricular contraction to happen with more ease because normally lung resistance is quite small to accommodate an average right ventricular systole. The presumption here is that right ventricular systole is orchestrated with an inspiration, i.e. the inspiration may be almost synchronous with the systole but not necessary equal in length. Because of the phenomenon of lung hysteresis, I may guess that expiration is more concerned with gas exchange in the lungs than inspiration may be (the model may be instantaneous more than sloping in this regard) and this would suggest that right ventricular diastole, when no more blood is ejected into the lungs, is almost synchronized with expiration as air is exhaled out; right ventricular systole/ lung inspiration > right ventricular diastole/ lung expiration, and this would be my hypothesized cardiorespiratory cycle (1).

The same idea may be applied on the left heart: left ventricular systole/ arterial recoil and capillary refilling > left ventricular diastole/ capillary resilience, when almost gas and metabolite exchange takes place between blood and tissues, i.e. again a more instantaneous than sloping model is suggested (2). The movement of fluid in the vicinity of the capillaries would follow a rather sloping model where a fluid outflow gradient on the arterial side of the capillary may be appropriately counterbalanced by another fluid inflow gradient on the venous side.

I may be eligible to confer this package of cardipulmonary assumptions the term: Gharabawy’s cardiorespiratory axioms. Though the right blood circulation may seem shorter than the left one, the total paths of deoxygenated and oxygenated blood seem to be equal. The two assumptions noted above as (1) and (2) can be represented as follows:
the clapper and the intonation room 2 (2)