Cardiovascular System Functions and Structures

Cardiovascular System Functions

• Four major functions of the cardiovascular system: Transportation of oxygen, carbon dioxide, heat, hormones, white blood cells, nutrients, and waste products.
• Substances transported: nutrients (glucose, amino acids) from gastrointestinal tract to body cells, hormones from endocrine glands to target tissues, waste products (urea, creatine) from various organs to kidneys and other organs, oxygen & nutrients to muscles & organs, and lymphatic cells/immune substances to infection/inflammation sites.

Heart Structures

• The left ventricle has thicker walls than the right ventricle because it pumps blood to the entire body, requiring greater pressure.

Blood Vessels

• Arteries carry blood away from the heart, branching into progressively smaller vessels (arterioles, capillaries).
• Capillaries have thin walls for gas, nutrient, and waste diffusion between blood and interstitial fluid.
• Venues and veins collect blood from capillaries and return it to the heart.
• Venous return is aided by:
  • Valves: Preventing backflow in veins.
  • Skeletal muscle pump: Muscle contractions help move blood.
  • Respiratory pump: Breathing helps move blood.

Arteries and Veins Microscopic Comparison

• Arteries have thicker walls of smooth muscle than veins to withstand high pressure. This elasticity regulates blood flow and maintains blood pressure via constriction/dilation.
• Veins are larger in diameter, appear collapsed or irregular, and have thinner walls.
• Capillaries are narrow, allowing red blood cells to pass through in single file.
• Blood vessels are lined with simple squamous epithelium.

Major Arteries

• Ascending aorta: Supplies oxygenated blood to the heart (coronary arteries) and the body.
• Aortic arch: Branches into major vessels supplying the head, neck, and upper limbs.
• Descending aorta (thoracic and abdominal): Supplies blood to the thoracic and abdominal regions, including organs and tissues
• Brachiocephalic trunk: Supplies blood to the right side of the head, neck and right arm
• Common carotid: Supplies blood to the head and neck.
• Celiac trunk: Supplies blood to the stomach, liver, pancreas, spleen, and intestines.
• Common hepatic: Supplies blood to the liver, gallbladder, and parts of the stomach and intestines.
• Splenic: Supplies blood to the spleen, pancreas, and part of the stomach.
• Renal: Supplies oxygenated blood to the kidneys.
• Common iliac: Supplies blood to the lower limbs and pelvic regions.
• External/Internal carotid: Supplies blood to the face, scalp, neck, ears, and muscles of mastication; brain, eyes and orbit respectively.
• Vertebral: Supplies blood to the cervical spine, brainstem, and posterior brain.
• Basilar: Supplies the brainstem, cerebellum, and posterior cerebral hemispheres.
• Cerebral arterial circle: Provides redundant blood supply to the brain, protecting against potential ischema and maintaining blood flow.
• Subclavian: Supplies the upper limbs, neck, brain, and part of the thoracic wall
• Axillary: Supplies the shoulder, axilla, and upper limb.
• Brachial: Supplies the upper arm, elbow joint, and forearm.
• Ulnar: Supplies the medial side of the forearm and hand.
• Radial: Supplies the lateral side of the forearm, wrist and hand.
• External & Internal iliac: Supplies blood to the lower limbs and pelvic regions respectively.
• Femoral: Supplies the thigh, knee, hip joint.
• Popliteal: Supplies the knee joint, muscles of the knee and lower leg.

Major Veins

• Superior vena cava: Drains deoxygenated blood from the upper body.

• Brachiocephalic: Drains blood from the head, neck, and upper limbs.

• Internal jugular: Drains blood from the brain, face, neck.

• External jugular: Drains blood from the face, scalp, neck.

• Inferior vena cava: Drains deoxygenated blood from the lower body.

• Renal: Drains the kidneys.

• Splenic: Drains the spleen, stomach, pancreas, and intestines.

• Hepatic: Drains the liver.

• Hepatic portal: Carries blood from the digestive organs to the liver.

• Subclavian: Drains blood from the upper limb, neck, and chest.

• Axillary: Drains blood from the upper limb, shoulder, chest, and arm.

• Cephalic: Drains blood from the lateral forearm and hand.

• Brachial: Drains blood from the upper arm, elbow, and forearm.

• Basilic: Drains blood from the medial forearm, upper arm, and hand.

• Ulnar: Drains blood from the medial forearm and hand.

• Radial: Drains blood from the lateral forearm, thumb, and hand.

• Common iliac: Drains blood from the lower limbs and pelvic regions

• External iliac: Drains blood from the lower limbs, anterior abdominal wall.

• Internal iliac: Drains blood from pelvic organs, gluteal region.

• Femoral: Drains blood from the thigh, kneee, lower leg.

• Great saphenous: Drain blood from the superficial structures of the lower leg and foot

• **Popliteal:**Drain blood from the knee joint, muscles of the knee, and lower leg.

Cerebral Arterial Circle

• Redundant blood supply to the brain; prevents ischemia.

Hepatic Portal System

• Carries blood from the digestive tract to the liver for nutrient processing and detoxification.

Fetal Circulation

• Placenta: Facilitates gas and nutrient exchange between mother and fetus (no adult equivalent).
• Umbilical arteries: Carry deoxygenated blood to the placenta.
• Umbilical vein: Carries oxygenated blood and nutrients from the placenta.
• Ductus venosus: Shunts blood from umbilical vein to inferior vena cava, bypassing fetal liver.
• Foramen ovale: Shunts oxygenated blood from right atrium to left atrium, bypassing lungs (fossa ovalis in adult).
• Ductus arteriosus: Shunts blood from pulmonary trunk to aorta, bypassing lungs (ligamentum arteriosum in adult).
• Fetal structures degenerate after birth.

Lymphatic System

• Three main functions:

  • Fluid balance
  • Immune defense
  • Nutrient absorption (fats/fat-soluble vitamins)

• Lymph formation: Excess interstitial fluid enters lymphatic capillaries.

• Lymph return: Enters lymphatic vessels, filtered by lymph nodes (phagocytes destroy pathogens), and returns to blood via subclavian veins.

• Lymphatic organs/tissues: Thymus (T cell maturation), spleen (filters blood), lymph nodes (filter lymph, immune response), tonsils (trap pathogens), aggregated lymphatic follicles in intestines (immune surveillance), appendix (immune surveillance of gut flora), bone marrow (blood cell production including lymphocytes)

• Lymphatic vessels and ducts: Collect interstitial fluid and return it to the blood (thinner walled and more valves than veins)

• Edema: Swelling due to fluid accumulation in tissues.

Explore the essential functions and structures of the cardiovascular system in this quiz. Learn about the transportation roles, heart anatomy, and blood vessel types critical for maintaining body health. Test your understanding of how nutrients and gases are exchanged within this intricate system.