Circulatory System II Overview

Circulatory System II

• Venules have the lowest pressure in the circulatory system.
• Capillaries facilitate gas exchange.

Great Vessels

• The aorta originates from the left ventricle.
• Initially, the aorta ascends, then curves downwards.
• The aorta is divided into ascending, arch, and descending portions (thoracic and abdominal), based on its location.

Aortic Arch

• The aortic arch curves superior to the heart in a U shape.
• Three major arteries branch from the arch: brachiocephalic trunk, left common carotid artery, and left subclavian artery.

Arteries of the Upper Limb

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

Arterial Terminations in the Upper Limb

• The subclavian artery provides blood to the upper extremity.
• The axillary artery, a continuation of the subclavian artery, extends to the armpit region and branches into the brachial artery.
• The brachial artery ends in the forearm by branching into the radial and ulnar arteries.

Arteries of the Lower Limb

• The femoral artery extends to the back of the knee, transitioning into the popliteal artery.
• The popliteal artery forms branches for the anterior and posterior aspects of the knee.

Venous System (Upper Limb)

• The superior vena cava receives blood from the upper extremities and head.
• The internal jugular and subclavian veins unite to form the brachiocephalic veins.
• The right and left brachiocephalic veins combine to form the superior vena cava.

Venous System (Lower Limb)

• The inferior vena cava collects blood from the lower extremities and abdomen.
• The internal and external iliac veins merge to form the common iliac vein.
• Right and left common iliac veins fuse to form the inferior vena cava.
• Veins of the lower limb such as the great saphenous and small saphenous veins.

Intravenous Injections

• Intravenous injections involve inserting a needle into a vein to administer medicine or fluids.
• Different injection angles are used depending on the target tissue (e.g., subcutaneous, intramuscular, or intradermal).