Of your many organs, the vital ones number five,
Note that without them, you could not survive. They are the brain, heart, lungs, kidneys, and liver!
We will now discuss the functions they deliver!
The BRAIN lets you think, but also does much more!
Like maintaining homeostasis and secreting hormones galore!
I act like a thermostat, using negative feedback, If parameters diverge, I SET them back on track!!!
I ensure proper body temp and water content, Abnormal blood glucose, oxygen, pH I prevent!
Through perception I gather environmental sensory input,
Providing info for rapid, coordinated motor output.
I motivate you to perform behaviors promoting survival,
Seeking food, water, shelter, mates, all of which are vital!
After these behaviors, I release dopamine as a treat
(Because this encourages these actions to repeat!)
Since behaviour is driven by brain activity, it’s plain,
That changes in behaviour mean changes in your brain!
Encoding, storage, retrieval allow memory and learning,
So past info is useful for situations that are recurring!
Thanks to my motor systems, body movements get initiated,
From breathing to limb position, I make you animated!
My suprachiasmatic nucleus can tell day from night,
Controlling circadian rhythms, it’s reset by daylight!
The HEART circulates blood to reach all your tissues,
Providing them with oxygen, so they function without issues.
Two atria and two ventricles compose my four chambers,
The left side is larger to accommodate more labours!
The right side pumps your blood, to the lungs and back,
Doing pulmonary circulation, it’s job is fairly slack.
The left side pumps to every body location, Except for the lungs, in systemic circulation!
We LUNGS are the organs that allow you to breathe
Alveoli, our functional units, this function bequeath!
Performing gas exchange, extracting oxygen from air,
Which enters your bloodstream, while sending CO2 back there!
Going to the lungs is the trachea, which leads to,
The bronchi, bronchioles, then to the alveoli. The right lung is larger, the left hugs the heart tight!
The left lung has two lobes, but there are three on the right!
We lungs cannot power inhalation on our own, We just expand with the thoracic cavity as shown!
It is I your LIVER, with over 500 functions, Including protein and hormone production.
I filter blood and hold 13% of blood volume, Detoxifying blood from toxins, alcohol, and drugs - BOOM!
Senescent red blood cells say their farewells, As they undergo hemolysis thanks to Kupffer cells!
Kupffer cells are a kind of tissue resident macrophage,
With bacterial endotoxins and bacteria they engage!
Now the reason you don’t bleed to death from a papercut
Is thanks to clotting factors – a natural Band-Aid – WHAT?!
These cause hemostasis, which stops your bleeding By forming a hemostatic plug, for blood loss impeding!
I also produce chemicals for digestion and growth!
My bile helps digestion and it absorbs fats and vitamins, both!
I regulate blood sugar levels, just so you know!
Storing glycogen if it’s high, releasing glucose if it’s low!
We are the KIDNEYS! A fifth of cardiac input we receive!
We filter blood and make urine – till your bladder you relieve!
We each have a million nephrons, our structural and functional units,
At the nephron’s start, filtration occurs in the glomerulus!
Spanning the cortex and medulla, nephrons bear the burden,
Of filtration, reabsorption, secretion, and excretion to produce urine!
Kidneys control the volume of various body fluid compartments,
Help regulate blood pressure, and remove toxins of all assortments.
We excrete metabolic waste and control electrolyte concentrations,
Expelling hydrogen, ammonium, potassium in our secretions.
Other secretions into urine include urea, from protein catabolism,
And uric acid, from nucleic acid metabolism.
But water, sodium, glucose, amino acids and bicarbonate,
Are reabsorbed into the body, not released when you urinate!
Some other kidney functions on the nephron don’t depend,
Like synthesizing hormones, erythropoietin and renin.