Functions of the Internal Organs

Heart

·          Pump oxygenated blood to cells

·          Pump deoxygenated blood to lungs

·          Maintain blood pressure

Lungs

·          Oxygenate Blood

·          Expire Carbon Dioxide

·          Aid in acid base balance

·          Involved in beat to beat variability of Heart

·          Converts Angiotensin I to Angiotensin II, responsible for regulate blood pressure

Kidney

·          Removes waste products from blood

·          Regulates fluid volume, reabsorbtion and excretion

·          Involved in Blood pressure regulation

·          Secretes erythropoietin which stimulated marrow to make RBC

·          Secretes rennin which regulates blood pressure

·          Secretes active form of Vit D which helps maintain calcium balance for bones

·          Regulates acid base balance

·          Involved in inorganic electrolyte balance

Spleen

·          Acts like a large lymph node involved in immunological functions , like the production of antibodies and the maturation of B- and T-lymphocytes, and Macrophages

·          Acts as a blood filter to remove waste, including damaged red blood cells, platelets, and bacteria, through phagocytosis by macrophages and neutrophils

·          Removes hemoglobin from RBC and recirculates it

·          Acts as a reservoir for various other white blood cells and platelets

·          Acts as a filter against foreign organisms that infect the bloodstream

·          Creates new blood cells especially during fetal debelopment

Liver

Endocrine functions

·          Secretes insulin-like growth factor 1 (IGF-1) in response to growth hormone, this encourages growth by inducing mitosis in many tissues, especially bone.

·          Involved in the production of vitamin D.

·          Converts triiodothyronine (T3) from thyroxine (T4).

·          Secretes angiotensinogen, which is acted upon by renin in the kidney to form angiotensin.

·          Metabolizes and transforms hormones

Clotting functions

·          Produces many of the plasma clotting factors, especially prothrombin and fibrinogen.

·          Makes bile salts,  important for the absorption of vitamin K, necessary for production of the clotting factors.

Plasma proteins: Creates and secretes albumin in the plasma, acute phase proteins , binding proteins for steroid hormones, lipoproteins, and trace elements,  and other proteins

Digestive functions through bile production and secretion

·          Creates and secretes bile acids, important for digestion and                 absorption of fats.

·          Neutralizes acid in the duodenum by secreting into the bile a bicarbonate-rich solution of inorganic ions, that neutralizes acid in the duodenum.

Organic metabolism

·          Changes plasma glucose into glycogen and triacylylycerols in the absorptive phase.

·          Produces triacylylycerols and secretes it as lipoproteins in the absorptive phase.

·          Changes glucose from glycogen and other precursors –gluconeogenesis- during the postabsorptive phase and lets the glucose into the blood.

·          Changes fatty acids into ketones when fasting.

·          Manufactures urea, the waste product of amino acid and protein catabolism, and discharges it into the blood to be dealt with be the kidneys.

Cholesterol Metabolism

·          Manufactures cholesterol and discharges it into the blood.

·          Secretes plasma cholesterol into bile.

·          Changes plasma cholesterol into bile acids.

Excretory, Detoxification, and Degradative Functions

·          Releases bilirubin and bile pigments into the bile

·          Excretes many foreign and endogenous organic molecules through the bile.

·          Biotransforms many foreign and endogenous organic molecules into other usable substrates or some improved way of excreting the metabolite.