Thoracic Region Aorta Branches

Cardiovascular System

• The aorta is the largest blood vessel in the human body, branching into:
  • Ascending aorta: provides blood to the heart
  • Aortic arch: supplies blood to the head, neck, and arms
  • Descending (or thoracic) aorta: supplies blood to the esophagus, spleen, and diaphragm
• Abdominal aorta:
  • Celiac trunk: first branch off the abdominal aorta, supplies blood to organs of the digestive and urinary systems
  • Common iliac arteries: terminal branches of the abdominal aorta, supply blood to the legs

Blood Components

• Blood contains:
  • Plasma (55% of total blood volume): liquid component, comprising 91% water and 8% solid components (clotting factors, proteins, electrolytes, and immunoglobulins)
  • Red blood cells: transport oxygen
  • White blood cells: part of the immune system, help fight diseases and infections
  • Platelets: cells that help with blood clotting
• Plasma is replenished every 48 hours by drinking fluids
• Human plasma is used for various purposes after donation, with type-matching for plasma being the opposite of type-matching for blood

Blood Clotting

• Prothrombin time (PT) test: measures the time it takes for blood to produce a thrombus (blood clot)
• Normal PT time: 0.8-1.1 seconds (11-13 seconds INR)
• PT test evaluates plasma clotting factors, which are used in the coagulation cascade process to convert fibrinogen into fibrin, leading to clot formation

Venous System

• Superior and inferior vena cava:
  • Superior vena cava: collects blood from above the diaphragm
  • Inferior vena cava: collects blood from below the diaphragm, is longer and wider than the superior vena cava
• Both vessels return blood to the heart, which is then oxygenated and re-circulated

Heart Circulation

• Heart has its own circulatory system, supplying oxygenated blood and removing deoxygenated blood
• Middle cardiac vein: collects deoxygenated blood from the ventricles and ventricular septum, emptying into the coronary sinus, which returns blood to the right atrium

Urinary System

• Comprised of kidneys, ureters, urinary bladder, and urethra
• Functions: create, store, and transport urine, removing toxins and waste from the body
• Organs receive arterial, venous, and nerve supply from different vessels and nerve complexes
• Common conditions affecting the urinary system include incontinence, urinary tract infections, urinary bladder infections, and kidney stones

Endocrine System

• Comprised of glands that secrete hormones, which stimulate various bodily functions
• Hormones are either proteins or steroids, binding to specific cells or organs through receptors
• Examples of hormones and their functions:
  • Testosterone and estrogen: sex hormones responsible for sexual development
  • Insulin: regulates blood sugar levels
  • Growth hormone: regulates physical growth in children
• Hormone regulation is accomplished by the hypothalamic-pituitary axis

Growth Hormone

• Produced in the anterior pituitary gland
• Regulates physical growth in children
• Hypo-secretion leads to pituitary dwarfism, while hyper-secretion leads to gigantism
• Hyper-secretion in adulthood results in acromegaly

Thyroid Gland

• Produces hormones essential for metabolism
• Requires iodine to form properly, otherwise leading to goiter (enlargement of the thyroid gland)
• Hypothyroidism: underactive thyroid gland, resulting in slowed metabolism
• Hyperthyroidism: overactive thyroid gland, resulting in Graves' disease and symptoms like bulging eyeballs (exophthalmos)

Hypothalamus

• Small part of the brain, allowing communication between the nervous and endocrine systems
• Regulates homeostasis, including temperature and water regulation
• Functions closely with the pituitary gland, releasing hormones such as antidiuretic hormone (ADH), oxytocin, and growth hormone-releasing hormone (GHRH)
• Malfunction can cause various problems, including Prader-Willi syndrome and Familial Diabetes Insipidus