You'll never sail among the Islands of Langerhans or drift lazily down the aqueduct of Sylvius. And don't expect to stroll along the banks of Hunter's Canal, or watch the sun go down behind McBurney's point, explore the Fissure of Rolando or ride through the Tunnel of Corti. You'll never trundle the Bundle of Vicq d' Azyr, or pillow your head no Passavant's Cushion, or vacation in Wernicke's Centre. Nor will you wall under the Palmar Arch, or Loop the Loop of Henle. And you may travel the whole world over and never gaze down upon Pacchionian depression or stand in the shadow of the Pyramids of Malpighi. Because - they are parts of the human body!!!!

Iron is critical to a number of
synthetic and enzymatic
processes. Most of the body iron
is part of the hemoglobin
molecule where iron serves a key
role in oxygen transport. Iron is
recycled and thus conserved by
the body. Daily intake ( 1 mg ) s
balanced against small daily
losses (1 mg ).
The amounts shown in the Fe
Cycle Card are in mg of iron lost
or gained per day. They were
derived in the following manner.
The average blood volume in a
70 kg man is 5,000 ml.
There are 150 grams of
hemoglobin in each liter of
blood, therefore there are 750 g
of hemoglobin in the body.
Each gram of hemoglobin
contains approximately 3.3 mg of
iron or 2475 mg of iron in the
body.
Dividing the 2475 mg total by the
120 day average RBC lifespan
results in the iron needed per
day or 20.6 mg iron/day.
Hemoglobin Fe 2200 mg
Ferritin & Hemosiderin 1000 mg
Myoglobin Fe 300 mg
Other Fe (cytochromes; enzymes) 100 mg
Total Body Iron 3600 mg
An average adult in the U.S. on a
2,500 calorie diet ( 6 mg of
iron/1,000 kcal) ingests 15 mg of
iron daily. Only 5-10 % or about
1.0 mg of dietary iron is
absorbed as ferrous iron (Fe++),
mainly in the duodenum and
upper jejunum where the pH is
low. The mucosal cells oxidize the
ferrous iron to ferric iron
, which is then
complexed with apoferritin to
form ferritin. Some of the ferritin
is transported out of the mucosal
cell into the plasma bound to
transferrin. Thus bound, iron can
be transported to the bone
marrow or iron storage sites
where it is stored as either
ferritin or hemosiderin.

Most cells have transferrin
receptors (CD 71) to which iron
ladden transferrin binds. The
receptor-transferrin-iron
complex is then incorporated
into the cytosol by endocytosis.
In red cells the endocytotic
vacuole fuses with a lysozyme,
where at an acid pH the iron (Fe+
+) is released from transferrin
and transported to mitochondria
where it is incorporated into
heme, the ferrous iron complex
of protoporphyrin IX.
Fe
Although iron is utilized in
virtually all cells, the bulk of body
iron is found in erythrocytes with
lesser amounts in myoglobin.
Large amounts of iron are
required during growth periods
in infant, childhood and teenage
years.
Transferrin carries iron to the
bone marrow where it is
accepted into RBCs via a
transferrin receptor (CD71) and
incorporated into heme for use
in hemoglobin.
Not all erythrocytes develop and
mature successfully. Some die in
the marrow and their iron is
salvaged by macrophages. This
failure to mature resulting in
death in the marrow is known as
ineffective erythropoiesis.

Normally only small amounts of
iron are lost daily as hair, skin,
urinary bladder,and
gastrointestinal cells are shed.
This amount can easily be
replaced by dietary intake.
With bleeding, larger amounts of
iron can be lost. The most
common normal blood losses are
due to menstruation and
pregnancy.

Glucose is by far the most
common carbohydrate and classified as a monosaccharide,
an aldose, a hexose, and is a reducing sugar. It is also known
as dextrose, because it is dextrorotatory (meaning that as
an optical isomer is rotates plane
polarized light to the right and also an origin for the D
designation. Glucose is also called blood sugar as it circulates in the blood at a
concentration of 65-110 mg/mL of blood.
Glucose is initially synthesized by chlorophyll in plants using carbon dioxide from the air and
sunlight as an energy source. Glucose is further converted to
starch for storage.

Ring Structure for Glucose:

Up until now we have been
presenting the structure of
glucose as a chain. In reality, an
aqueous sugar solution contains
only 0.02% of the glucose in the
chain form, the majority of the
structure is in the cyclic chair
form.
Since carbohydrates contain both
alcohol and aldehyde or ketone
functional groups, the straight-
chain form is easily converted
into the chair form - hemiacetal
ring structure. Due to the
tetrahedral geometry of carbons
that ultimately make a 6
membered stable ring , the -OH
on carbon #5 is converted into
the ether linkage to close the
ring with carbon #1. This makes
a 6 member ring - five carbons
and one oxygen.
Steps in the ring closure
(hemiacetal synthesis):
1. The electrons on the alcohol
oxygen are used to bond the
carbon #1 to make an ether (red
oxygen atom).
2. The hydrogen (green) is
transferred to the carbonyl
oxygen (green) to make a new
alcohol group (green).
The chair structures are always
written with the orientation
depicted on the left to avoid
confusion.
Hemiacetal Functional Group:
Carbon # 1 is now called the
anomeric carbon and is the
center of a hemiacetal functional
group. A carbon that has both an
ether oxygen and an alcohol
group is a hemiacetal.

Glucose in the Chair Structures:

The position of the -OH group on
the anomeric carbon (#1) is an important distinction for carbohydrate chemistry. The Beta position is defined as
the -OH being on the same side of the ring as the C # 6. In the
chair structure this results in a horizontal projection.
The Alpha position is defined as the -OH being on the opposite
side of the ring as the C # 6. In the chair structure this results in a downward projection.
The alpha and beta label is not
applied to any other carbon -
only the anomeric carbon, in this
case # 1.

As the heart undergoes
depolarization and
repolarization, electrical currents
spread throughout the body
because the body acts as a
volume conductor. The electrical
currents generated by the heart
are commonly measured by an
array of electrodes placed on the
body surface and the resulting
tracing is called an
electrocardiogram (ECG, or EKG).
By convention, electrodes are
placed on each arm and leg, and
six electrodes are placed at
defined locations on the chest.
These electrode leads are
connected to a device that
measures potential differences
between selected electrodes to
produce thecharacteristic ECG
tracings.
Some of the ECG leads are bipolar
leads (e.g., standard limb leads)
that utilize a single positive and a
single negative electrode
between which electrical
potentials are measured.
Unipolar leads (augmented leads
and chest leads) have a single
positive recording electrode and
utilize a combination of the other
electrodes to serve as a
composite negative electrode.
Normally, when an ECG is
recorded, all leads are recorded
simultaneously, giving rise to
what is called a 12-lead ECG.