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No, it's not true. Truth is artery carries away blood from heart under pressure while vein carries blood towards heart.


Usually arteries carry oxygenated blood and veins carry de-oxygenated blood. But there are exceptions in biology .

The pulmonary artery carries de-oxygenated blood, from the right ventricle of the heart to the lungs.

The pulmonary veins , which are 4 in number, carry oxygenated blood from the lungs to the left atrium of the heart.

The following diagram of the heart and the great vessels shows pulmonary artery and veins.
The pulmonary artery is colored blue, which indicates it carries de-oxygenated blood.
And the pulmonary veins are colored red, which indicates they carry oxygenated blood.


First we have to see the composition of cheese, then we will know which enzymes are required to digest it.



Like many food, cheese also contains a lot of water. It also contains lots of calcium, other minerals and vitamins. Our body must digest the protein, fat and carbohydrate components of cheese.

Cheese contains mainly milk protein casein. For digestion of protein, proteolytic enzymes are needed.

a) Such enzymes are present in gastric juice (e.g. pepsin ) and also in pancreatic juice (e.g. trypsin, chymotrypsin ).

b) Protein is broken down first in long polypeptides within stomach and then in smaller peptones within small intestine.

c) Lastly, carboxypeptidase (present in pancreatic juice) and aminopeptidase (present in intestinal juice) enzymes help in final digestion to produce absorbable amino acids.

Fat portion of cheese is digested by enzyme lipase , secreted by both intestinal glands and exocrine pancreas. Digestion of fat can take place in small intestine, only after mixing of bile juice. Bile salts present in bile help in emulsification of dietary fat to form microscopic fat globules. Lipase can then act on fat molecules to release absorbable fatty acids and glycerol molecules.

Sugar present in cheese is lactose: it is a disaccharide. Lactase is the enzyme, present in intestinal juice, that breaks down lactose into glucose and galactose.


The Brain...


Derived from Greek, it basically mean "No brain inside"...

During pregnancy, the brain normally develops from the Neural Tube into the embryonic (vertebrate) brain. Towards the end of development a differentiation takes place into the Forebrain, Midbrain and Hindbrain.

Pic: (Courtesy of https://en.wikipedia.org/wiki/Cerebrum)

enter image source here

Although in anencephaly there can be a total lack of brain tissue, the term usually refers to a lack of the Telencephalon.
The Telencephalon develops into the *Cerebrum, the "Main Brain".

Needless to say, the foetus has no future, and, if born at all, doesn't survive for more than a few hours, a day or two at most....


Skeletal muscles.


  • Skeletal muscles or voluntary muscles can be controlled by our will.
  • These are also known as striated muscles as well as voluntary muscles.
  • Skeletal muscle is one of three major muscle types, the others being cardiac muscle and smooth muscle.

  • It is a formed of striated muscle tissue which is under the 'voluntary' control of the somatic nervous system.

  • Most skeletal muscles are attached to bones by bundles of collagen fibers known as tendons.



Here's what I find.


Of our total iron intake,

  • About 10 % to 15 % comes from meat, fish, and poultry as heme
  • About 85 % to 90% comes from grains and vegetables as non-heme iron

Absorption of heme iron

Most of the iron from digested food is absorbed through the duodenal villi.

Heme iron is moved across the cell membrane into the cytoplasm by facilitated transport through heme transporters.

(From SlideShare)

Proteolytic enzymes in the cytosol release the #"Fe"^"2+"# ions, which enter a common pool with non-heme iron.

Absorption of non-heme iron

To be absorbed, non-heme iron must be in the #"Fe"^"2+"# form. Any iron in the #"Fe"^"3+"# form is first reduced to #"Fe"^"2+"# by a ferric reductase.

Intestinal absorption
(From ResearchGate)

A protein called divalent metal transporter 1 (DMT1) then transports the iron into the cell through the cell membrane.

The cell can then either

  • store the #"Fe"^"2+"# by complexing it as ferritin or
  • release the #"Fe"^"2+"# into the body via the iron exporter, ferroportin

The enzyme hephaestin helps ferroportin transfer iron across the cell wall.

The #"Fe"^"2+"# ions are again oxidized to #"Fe"^"3+"# and bound to plasma transferrin for transport throughout the body.


They have a second function...


The (bio-)chemicals mentioned are Neurotransmitters.

But they have a second function: they also act as Neuromodulators. There is a marked difference in both mode of operation and result:

Neurotransmitters act exclusively within the synapse between two neurons, effecting a fast impulse transfer. This results in either an IPSP (Inhibitory Post Synaptic Potential) or an EPSP (excitatory Post Synaptic Potential) in the receiving neuron.

Neuromodulators act in a different way: they seep into the nervous tissue, affecting whole regions of it.

Neurotransmitters usually bind to ionotropic receptors. More commonly referred to as Ligand-gated ion-channels. By binding, they open the channel to let ions flow through:

As mentioned, they operate strictly within the synaptic cleft, between two neurons: the Pre-synaptic and the Post-synaptic ones.

Neuromodulators act on different receptors on the neurons, and in a different way: they act on Metabotropic receptors.
Also known as secondary messengers, rather than transferring a signal like the Neurotransmitters mentioned above, they influence the mode of operation of the (post-synaptic) neuron.
To keep it simple: let's say they alter (modulate) the sensitivity of the accepting neuron: they can (indirectly) open or close ion-channels, and initiate other (intracellular) effects:



To put it in simple terms: Consider a play being performed in a theatre. The perception of the performance of the players on the stage can (will) be influenced by the lighting on the stage: Turning the lights to full power will represent a fine, sunny day, while switching them off resuls in the mood of a dark night.

Neuromodulators have the same effect: In contrast to neurotransmitters, in their role as modulators they act on multiple cells at the same time (whole regions), and the mode of operation is much slower.

But don't forget, the modulators mentioned can act as neurotransmitters as well.

To come back to the question: an imbalance in Neuromodulation WILL affect the mood a person is experiencing: a shortage will often lead to depression....

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