Life-Giving Blood
Made in His Image: Life-Giving Blood
By Randy J. Guliuzza, P.E., M.D. *
After 100 years, automobiles still need
engine oil, transmission fluid, brake fluid, antifreeze, power-steering fluid,
and so on.
Wouldn't it be great if just a single multipurpose fluid could be circulated from a
central reservoir?
Each part would use only the needed
properties of the fluid, exclude detrimental properties, and then send it back.
The new system’s worldwide impact would
ensure a huge market--and academic honors--for the clever developers.
This lucrative breakthrough, however, would
not be pioneering.
Just such a brilliant integration of fluid
properties to the diverse needs of the physical body has already been achieved
in human blood - in a self-starting process beginning about 15 days after
fertilization.
Heart and Blood Vessel Formation
The
first human cell divides rapidly, becoming a small cluster that implants inside
the uterus.
Initially it flattens out to a disc only a
few cells thick that is able to get nutrients by diffusion from maternal blood
circulation.
However, by two weeks after fertilization the
disc is becoming too thick for this, so the developing embryo urgently needs a
nutrient transport system.
Right on cue, blood and blood vessel
formation begin at the end of the second week in both the embryo and developing placenta.
Heart tubes (the precursor to the heart) form
and start pumping within seven days.
The cardiovascular system is the first organ
system to become functional--an important factor, since every cell depends on
blood to survive.
Vital Characteristics of Blood
Blood
is a liquid tissue. For normal human function, blood has to be
a fluid. Why?
Fluids can flow, carry either suspended or
dissolved solids and gases, and respond to even slight pressure changes by
continuously changing shape.
Blood and blood vessels, therefore, form an
incredibly flexible conduit--the exact shape of a person's body at any moment -
that connects the outside world to the deepest cells inside.
Cellular metabolic demands are relentless.
That is why nearly all of the estimated 60
trillion cells in the body - each one carrying out an average 10 million
chemical reactions per
second - are
always close to blood vessels bringing oxygen and fuel.
Blood is made up of solid (formed) parts such
as oxygen-carrying red blood cells (RBCs), disease-fighting white blood cells
(WBCs), and platelets suspended in a liquid that is 92 percent water.
This liquid, called plasma, has about 120 dissolved components that include oxygen,
carbon dioxide, glucose, albumin, hormones, and antibodies.
Sensors continuously monitor the concentrations of these items and make swift adjustments.
Vital body functions like normal acid-base
ratio, intracellular water content, blood’s ability to flow through vessels,
and managing body heat production depend as much on correct concentrations as
the correct mix of components.
Fetal Blood Production
The
embryo makes RBCs first, his most necessary blood component.
These distinctive cells are made by the inner
lining of blood vessels in a temporary structure outside the embryo called the yolk sac, which in people is actually a "blood
forming sac" that never contains yolk.
This misguided name was given because it was
believed to have "arisen" in a pre-human animal ancestor and because
it initially contains a yellow substance.
The progenitor RBCs eventually migrate from
the yolk sac to the liver and spleen, which become the lead cell-forming sites
by the mid-second month of gestation. By the fifth month, bone marrow is
sufficiently formed to take over for nonstop lifelong production.
Interestingly, even in adulthood if the body
is stressed by a shortage of RBCs, the spleen and liver can resume production
as emergency backup sites.
In children, blood formation occurs in the
long bones such as the upper leg and shin. In adults, it occurs mainly in the
pelvis, cranium, vertebrae, and sternum.
However, development, activation, and some
proliferation of certain WBCs occur in the spleen, thymus gland, and lymph
nodes.
Normally, sensor-control mechanisms balance
mature RBCs from their production to their loss--which is about 1,200,000 cells per second.
How does the marrow produce these prodigious
numbers of cells?
Blood Formation: A Precisely-Planned Process
Blood
formation begins with a self-renewing population of pluripotent stem cells that are capable of developing
into any type of blood cell lineage (RBC, WBC, or
platelet).
They reproduce by making exact copies of
themselves called clones or daughter cells.
Some daughter cells or originals remain as pluripotent stem cells,
but the rest will be “committed” to specific lineage pathways.
Which cells stay as stem cells and which get
committed is a random process.
In contrast, the survival and expansion of
cells in each lineage is precisely controlled by dozens of interacting chemical signals
called colony
stimulating factors (CSFs)
-some produced in other body tissues.
CSFs control numerous activities, including
turning certain genes on and off at just the right time so each unique feature
of the cells is made.
The marrow provides a protected
microenvironment where immature cells grow on a meshwork of fat cells, large
WBCs called macrophages, and cells lining the marrow.
The meshwork compartmentalizes the nurturing
process and also secretes vital CSFs.
Proper growth is stimulated by strict
regulation, in stepwise fashion, over both order and timing of when 12 major CSFs are introduced to the
blood cells.
Controls are so exact that concentrations of CSFs from other tissues can be as low as
10-12 molar (like one grain of salt dissolved in about 27,000
gallons of water).
Amazingly, at certain steps in the process
some of the maturing (or mature) blood cells themselves emit CSFs to direct their own development or
even control the meshwork.
For RBCs, a crucial stimulating hormone is erythropoietin, commonly called EPO. Without EPO, no RBCs
would be made. EPO is steadily circulated, keeping RBC production at the normal
rate.
But "normal" for a ten-year-old
girl at sea level may not be "normal" for a sixty-year-old man living
on a mountain.
The genes with instructions for making EPO
are controlled by stimulants known as hypoxia-inducible factors (whose function depends on several vital
enzymes).
These factors activate EPO DNA but not in response to the number of
RBCs. Rather, low
oxygen concentrations induce
more EPO production, which normally results in rapidly rising RBC numbers.
By regulating just exactly what is
needed--the blood's ability to carry adequate oxygen--the optimum number of
RBCs running at maximum oxygen capacity is continuously and efficiently
adjusted.
Therefore, it would be fitting for EPO to be
produced mainly in an organ that is very sensitive to changes in blood
pressures and oxygen content, such as the renal cortex of the kidney--which it
is.
Integrating Blood Properties with Organ Function
The
familiar biconcave shape of human RBCs bestows the highest possible
membrane surface area relative to intracellular volume and oxygen saturation
rate.
This makes it possible for over 250 million
hemoglobin molecules in each of the billions of RBCs to be oxygen-loaded
in a fraction of a second.
Recall that nearly all body cells are in
close proximity to blood vessels. By necessity, most of these vessels are tiny
capillaries, of which 40 could be put side-by-side in the diameter of a human
hair.
RBCs are twice the diameter of a capillary
but can actually squeeze through it. How? Structural properties in the RBC's
membrane allow the cell shape to be incredibly deformed and then spring back to
normal.
Five specialized structural proteins confer
this important ability and a genetic defect in any causes diseases due to
rupturing of less-flexible RBC membranes.
RBCs are themselves living tissues. It would
be possible for RBCs to consume much of their oxygen payload with little left
to supply other tissues.
However, RBCs have enzymes to power their
metabolic processes without the use of oxygen--so they consume none of their precious
cargo.
Several kinds of cells, like the clear cornea
and lens of the eye, need the oxygen and nutrients carried in blood but could
not function properly if coated in red blood cells.
This problem is overcome by a part of the eye
that acts like a blood filter. Using ultrafine portals--so small as to screen
out RBCs and other proteins - a crystal-clear water-based portion carries just
enough dissolved oxygen and nutrients.
After nourishing the cornea, the fluid is
reabsorbed - through another set of tiny holes - back into the bloodstream.
Cerebral spinal fluid and urine are some
other ultrafiltrates of blood in which only some of blood’s properties are
extracted to fill a need at a precise location.
Conclusion
From
the earliest days in the mother's womb until the day of death, a person's life
is in the blood.
Even a person-to-person gift of blood is
treasured and called "the gift of life."
Human blood is indeed a gift from the Lord
Jesus Christ, clearly testifying to His great creative abilities and the body’s
total unity of function.
The Bible says that the Lord Jesus' blood is
particularly special - in fact, "precious" (1 Peter 1:19).
Because it is able to redeem us and cleanse
us from all sin (1 John 1:9).
Let us
give glory "unto him that loved us, and washed us from our sins in his own
blood" (Revelation 1:5).
* Dr. Guliuzza is ICR's National Representative.
Cite this article: Guliuzza, R. 2009. Made in His Image:
Life-Giving Blood. Acts &
Facts. 38 (9): 10-11.
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Oh, the Blood of Jesus
Author: Anonymous
https://www.youtube.com/watch?v=HWdRsinKm2YBluegrassShilohWorshipMusic
CLICK HERE . . . to view complete playlist . . .
lyrics
1 Oh, the blood of Jesus,
Oh, the blood of Jesus,
Oh, the blood of Jesus,
it must not suffer loss.
Oh, the blood of Jesus,
Oh, the blood of Jesus,
it must not suffer loss.
2 Oh, the word of Jesus,
Oh, the word of Jesus,
Oh, the word of Jesus,
it cleanses white as snow.
Oh, the word of Jesus,
Oh, the word of Jesus,
it cleanses white as snow.
3 Oh, the love of Jesus,
Oh, the love of Jesus,
Oh, the love of Jesus,
it makes His body whole.
Oh, the love of Jesus,
Oh, the love of Jesus,
it makes His body whole.
There is
power, power, power, power,
Wonder working pow'r,
In the blood, in the blood, of the Lamb, of the Lamb,
There is power, power, power, power,
Wonder working pow'r,
In the precious blood of the Lamb.
Wonder working pow'r,
In the blood, in the blood, of the Lamb, of the Lamb,
There is power, power, power, power,
Wonder working pow'r,
In the precious blood of the Lamb.
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