Week 9 - Circulatory

• What is the primary function of the circulatory system?

  Pumps and directs blood to all tissues
• What two vascular systems are included in the circulatory system?

  Blood and lymphatic vascular systems
• What is the estimated total length of blood vessels in an adult?

  100,000 to 150,000 kilometers
• What are the main components of the blood-vascular and cardiovascular systems?

  • The heart
  • Arteries
  • Capillaries
  • Veins
• What type of epithelium lines the internal surface of blood and lymphatic systems?

  Simple squamous epithelium called endothelium
• What are the functions of the circulatory system?

  1. Pumps and directs blood to all tissues
  2. Transports nutrients, hormones, and oxygen
  3. Moves wastes and carbon dioxide to disposal areas
  4. Aids in fighting pathogenic microorganisms
• What are the components of the cardiovascular system?

  • Blood vessels forming a closed circuit
  • Smooth muscle and connective tissue in vessel walls
  • Endothelium as a semipermeable barrier
• What is the innermost layer of blood vessels called?

  Tunica Intima
• What is the primary function of the tunica intima?

  Protective lining and regulates substance diffusion
• What is the middle layer of blood vessels known as?

  Tunica Media
• What is primarily found in the tunica media?

  Concentric layers of smooth muscle cells
• What is the outer layer of blood vessels called?

  Tunica Adventitia
• What is the composition of the tunica adventitia?

  Connective tissue with type I collagen and elastic fibers
• What are capillaries known for?

  Smallest and most numerous blood vessels
• What is the structure of capillaries?

  Single layer of endothelial cells surrounded by basement membrane
• How do capillaries optimize exchange between blood and tissues?

  Thin walls, extensive surface area, slow blood flow
• What are the two types of cells found in capillaries?

  Endothelial cells and pericytes
• What characterizes continuous capillaries?

  Many tight junctions for regulated metabolic exchange
• Where are continuous capillaries commonly found?

  Muscle, connective tissue, lungs, exocrine glands
• What is the structure of fenestrated capillaries?

  Sieve-like structure with small circular openings
• Where are fenestrated capillaries found?

  Kidneys, intestine, choroid plexus, endocrine glands
• What are discontinued capillaries also known as?

  Sinusoids
• What is the primary function of arteries?

  Carries oxygenated blood away from the heart
• How do veins differ from arteries?

  Thinner tunica adventitia and lower pressure
• What aids blood movement in veins?

  Contraction of smooth muscle and surrounding organs
• What prevents backflow of blood in veins?

  Valves projecting from the tunica intima
• What tissues make up the vascular wall?

  • Endothelium: semipermeable barrier
  • Smooth muscle: regulates blood pressure
  • Connective tissues: provide strength and elasticity
• What is the size of the heart?

  About the size of a clenched fist
• What is the primary function of the heart?

  Pumps blood to systemic and pulmonary circulations
• What is the innermost layer of the heart called?

  Endocardium
• What does the myocardium consist of?

  Mainly cardiac muscle arranged spirally
• What is the outermost layer of the heart?

  Epicardium
• What is the composition of the epicardium?

  Loose connective tissue lined by mesothelium
• What is blood classified as?

  A specialized connective tissue
• How much blood does an average adult have?

  About 5 liters
• What are the formed elements of blood?

  Erythrocytes, leukocytes, and thrombocytes
• What happens when blood leaves the circulatory system?

  Plasma proteins react to form a clot
• What is serum?

  Fluid portion of clotted blood
• What is plasma primarily composed of?

  92% water
• What is the chief plasma protein?

  Albumin