Circulatory System II Overview

Circulatory System II

• Venules have the lowest pressure.
• Capillaries are crucial for gas exchange.

Great Vessels

• The aorta emerges from the left ventricle.
• Initially, it ascends, then curves downwards.
• Sections are named:
  • Ascending aorta
  • Aortic arch
  • Descending aorta (divided into thoracic and abdominal aorta).
• Location is based on its position relative to the umbilicus and the thoracic and abdominal regions.

Aortic Arch

• Curves to the left, resembling an inverted "U."
• Superior to the heart.
• Branches off three major arteries in this order:
  • Brachiocephalic trunk
  • Left common carotid artery
  • Left subclavian artery

Arteries of the Upper Extremity

• The subclavian artery continues as the axillary artery, then the brachial artery.
• The brachial artery divides into the ulnar and radial arteries.

Intravenous Injection

• Tourniquet is used to facilitate vein access.
• Puncture site is covered to prevent contamination.
• Specimen is retrieved after successful vein puncture.
• Different angles of injection are used for various tissue depths:
  • Intramuscular (90°)
  • Subcutaneous (45°)
  • Intravenous (25°)
  • Intradermal (10° - 15°)

Veins of the Upper Limb

• Divided into superficial and deep veins.
• Deep veins have the same names as their corresponding arteries.
• Radial and ulnar veins join to form the brachial vein.
• The brachial vein, after passing the pectoralis major, becomes the axillary vein.
• The axillary vein continues as the subclavian vein.

Veins of Upper Limb (Continued)

• Superficial veins (cephalic and basilic) join in the forearm as the median cubital vein.
• This structure is located at the anterior elbow.

Veins of the Lower Limb: Superficial

• Arcus venosus dorsalis pedis
• Great saphenous vein (opens into femoral vein)
• Small saphenous vein (empties into popliteal vein)

Veins of the Lower Limb: Deep

• Anterior and posterior tibial veins, as well as fibular veins merge into the popliteal vein.
• The popliteal vein connects with the femoral vein within the thigh.

Inferior Vena Cava

• Venous blood from the lower extremities and abdomen enters through the inferior vena cava.
• Internal and external iliac veins unite to form the common iliac vein.
• The right and left common iliac veins merge to form the inferior vena cava.

Superior Vena Cava

• Blood from the upper body (head/neck/upper limbs) returns to the heart through the superior vena cava.
• Internal jugular veins and subclavian veins unite to form the brachiocephalic veins.
• The right and left brachiocephalic veins combine to form the superior vena cava.

Blood Pressure Measurement Sites

• Locations for measuring blood pressure in the upper and lower limbs are indicated.