Lecture XX

• I: VASCULATURE (BLOOD VESSELS). A: GENERAL OVERVIEW. 2: TYPICAL VESSELS. c: CAPILLARIES AND SUBTYPES

  • capillaries are also called exchange vessels
• I: VASCULATURE (BLOOD VESSELS). A: GENERAL OVERVIEW. 2: TYPICAL VESSELS. c: CAPILLARIES AND SUBTYPES

  • exchange vessels
  • single cell thick for vessel wall
• I: VASCULATURE (BLOOD VESSELS). A: GENERAL OVERVIEW. 2: TYPICAL VESSELS. c: CAPILLARIES AND SUBTYPES

  • exchange vessels
  • single cell thick for vessel wall
  • simple squamous epithelium
• I: VASCULATURE (BLOOD VESSELS). A: GENERAL OVERVIEW. 2: TYPICAL VESSELS. c: CAPILLARIES AND SUBTYPES

  • exchange vessels
  • single cell thick for vessel wall
  • simple squamous epithelium
  • simple diffusion: oxygen exits blood, carbon dioxide enters blood
  • protein transporter: can also move lipids, carbohydrates, amino acids, nucleic acids, vitamins
• I: VASCULATURE (BLOOD VESSELS). A: GENERAL OVERVIEW. 2: TYPICAL VESSELS. c: CAPILLARIES AND SUBTYPES

  • exchange vessels
  • single cell thick for vessel wall
  • simple squamous epithelium
  • simple diffusion: oxygen exits blood, carbon dioxide enters blood
  • protein transporter: can also move lipids, carbohydrates, amino acids, nucleic acids, vitamins
  • precapillary sphincter
• I: VASCULATURE (BLOOD VESSELS). A: GENERAL OVERVIEW. 2: TYPICAL VESSELS. c: CAPILLARIES AND SUBTYPES

  • precapillary sphincter
  • smooth muscle ring
• I: VASCULATURE (BLOOD VESSELS). A: GENERAL OVERVIEW. 2: TYPICAL VESSELS. c: CAPILLARIES AND SUBTYPES

  • precapillary sphincter
  • smooth muscle ring
  • controls flow of material
• I: VASCULATURE (BLOOD VESSELS). A: GENERAL OVERVIEW. 2: TYPICAL VESSELS. c: CAPILLARIES AND SUBTYPES

  • precapillary sphincter
  • smooth muscle ring
  • controls flow of material
  • protect capillary from being overfilled or has too high pressure
• I: VASCULATURE (BLOOD VESSELS). A: GENERAL OVERVIEW. 2: TYPICAL VESSELS. c: CAPILLARIES AND SUBTYPES

  • precapillary sphincter
  • smooth muscle ring
  • controls flow of material
  • protect capillary from being overfilled or has too high pressure
  • meta arterioles: bypass a full capillary bed if needed
• I: VASCULATURE (BLOOD VESSELS). A: GENERAL OVERVIEW. 2: TYPICAL VESSELS. c: CAPILLARIES AND SUBTYPES

  • meta arterioles: bypass a full capillary bed if needed
  • arteriovenosis anastomosis does the same job as meta arterioles
• Added Notes:

  • capillaries have no tunica interna, no tunica media, and hardly any tunica externa
  • precapillary sphincter deteriorates with age
  • meta arterioles are like extra stairs for another way down
• I: VASCULATURE (BLOOD VESSELS). A: GENERAL OVERVIEW. 2: TYPICAL VESSELS. c: CAPILLARIES AND SUBTYPES. i: CONTINUOUS CAPILLARY

  • most common
• I: VASCULATURE (BLOOD VESSELS). A: GENERAL OVERVIEW. 2: TYPICAL VESSELS. c: CAPILLARIES AND SUBTYPES. i: CONTINUOUS CAPILLARY

  • most common
  • only allows small molecules to enter or exit plasma
• I: VASCULATURE (BLOOD VESSELS). A: GENERAL OVERVIEW. 2: TYPICAL VESSELS. c: CAPILLARIES AND SUBTYPES. i: CONTINUOUS CAPILLARY

  • most common
  • only allows small molecules to enter or exit plasma
  • all cells touch each other, basal lamina is intact
• I: VASCULATURE (BLOOD VESSELS). A: GENERAL OVERVIEW. 2: TYPICAL VESSELS. c: CAPILLARIES AND SUBTYPES. ii: FENESTRATED CAPILLARY

  • limited presence
• I: VASCULATURE (BLOOD VESSELS). A: GENERAL OVERVIEW. 2: TYPICAL VESSELS. c: CAPILLARIES AND SUBTYPES. ii: FENESTRATED CAPILLARY

  • limited presence
  • large gaps between cells
• I: VASCULATURE (BLOOD VESSELS). A: GENERAL OVERVIEW. 2: TYPICAL VESSELS. c: CAPILLARIES AND SUBTYPES. ii: FENESTRATED CAPILLARY

  • limited presence
  • large gaps between cells
  • loose basal lamina
• I: VASCULATURE (BLOOD VESSELS). A: GENERAL OVERVIEW. 2: TYPICAL VESSELS. c: CAPILLARIES AND SUBTYPES. ii: FENESTRATED CAPILLARY

  • limited presence
  • large gaps between cells
  • loose basal lamina
  • allows more larger molecules to pass through the capillary wall
• I: VASCULATURE (BLOOD VESSELS). A: GENERAL OVERVIEW. 2: TYPICAL VESSELS. c: CAPILLARIES AND SUBTYPES. iii: SINUSOID CAPILLARY

  • very limited, seen in spleen and liver
• I: VASCULATURE (BLOOD VESSELS). A: GENERAL OVERVIEW. 2: TYPICAL VESSELS. c: CAPILLARIES AND SUBTYPES. iii: SINUSOID CAPILLARY

  • very limited, seen in spleen and liver
  • gaps between cells: large enough for blood cells and large proteins to enter and exit plasma
• I: VASCULATURE (BLOOD VESSELS). A: GENERAL OVERVIEW. 2: TYPICAL VESSELS. c: CAPILLARIES AND SUBTYPES. iii: SINUSOID CAPILLARY

  • very limited, seen in spleen and liver
  • gaps between cells: large enough for blood cells and large proteins to enter and exit plasma
  • spleen filters and recycles blood cells
  • liver sorts molecules from food
• Added Notes:

  • basal lamina tight at continuous capillaries
• I: VASCULATURE (BLOOD VESSELS). A: GENERAL OVERVIEW. 2: TYPICAL VESSELS. d: VENULES

  • gather blood from capillary bed
• I: VASCULATURE (BLOOD VESSELS). A: GENERAL OVERVIEW. 2: TYPICAL VESSELS. d: VENULES

  • gather blood from capillary bed
  • thin walled
• I: VASCULATURE (BLOOD VESSELS). A: GENERAL OVERVIEW. 2: TYPICAL VESSELS. d: VENULES

  • gather blood from capillary bed
  • thin walled
  • low in oxygen, high in carbon dioxide and waste
• I: VASCULATURE (BLOOD VESSELS). A: GENERAL OVERVIEW. 2: TYPICAL VESSELS. d: VENULES

  • gather blood from capillary bed
  • thin walled
  • low in oxygen, high in carbon dioxide and waste
  • very low pressure
• Added Notes:

  • venules have no tunica media or smooth muscle
  • heart is useless in the venules
  • skeletal muscle contractions move blood to the venules, not pressure
• Added Notes:

  • veins have some tunica media
• I: VASCULATURE (BLOOD VESSELS). A: GENERAL OVERVIEW. 2: TYPICAL VESSELS. e: VEINS

  • venules merge to veins
• I: VASCULATURE (BLOOD VESSELS). A: GENERAL OVERVIEW. 2: TYPICAL VESSELS. e: VEINS

  • venules merge to veins
  • goal: return blood to right ventricle
• I: VASCULATURE (BLOOD VESSELS). A: GENERAL OVERVIEW. 2: TYPICAL VESSELS. e: VEINS

  • venules merge to veins
  • goal: return blood to right ventricle
  • will have tunica media with smooth muscle
• I: VASCULATURE (BLOOD VESSELS). B: VENOUS RETURN

  • how do we get blood back to the right ventricle?
  • needs are dependent on metabolism
• I: VASCULATURE (BLOOD VESSELS). B: VENOUS RETURN. 1: SKELETAL MUSCLE PUMPS

  • contractions generate pressure gradient to move air or fluid
• I: VASCULATURE (BLOOD VESSELS). B: VENOUS RETURN. 1: SKELETAL MUSCLE PUMPS

  • contractions generate pressure gradient to move air or fluid
  • muscle contracts and squeezes veins
• Added Note:

  • left ventricle has a similar pressure gradient for arterioles
• I: VASCULATURE (BLOOD VESSELS). B: VENOUS RETURN. 1: SKELETAL MUSCLE PUMPS. a: VENOUS VALVES

  • same principle as heart valves
• I: VASCULATURE (BLOOD VESSELS). B: VENOUS RETURN. 1: SKELETAL MUSCLE PUMPS. a: VENOUS VALVES

  • same principle as heart valves
  • blood goes in one direction
  • move based on pressure gradients
  • made of dense irregular connective tissue
• I: VASCULATURE (BLOOD VESSELS). B: VENOUS RETURN. 1: SKELETAL MUSCLE PUMPS. a: VENOUS VALVES

  • same principle as heart valves
  • blood goes in one direction
  • move based on pressure gradients
  • made of dense irregular connective tissue
  • stay shut most of the time
• I: VASCULATURE (BLOOD VESSELS). B: VENOUS RETURN. 1: SKELETAL MUSCLE PUMPS. a: VENOUS VALVES

  • same principle as heart valves
  • blood goes in one direction
  • move based on pressure gradients
  • made of dense irregular connective tissue
  • stay shut most of the time
  • as muscle contracts, vessel is squeezed and valve opens
• I: VASCULATURE (BLOOD VESSELS). B: VENOUS RETURN. 1: SKELETAL MUSCLE PUMPS. b: PRESSURE GRADIENTS

  • built off skeletal muscle, contracts to oppose gravity