Cardiovascular System: Arterial Circulation

Arterial System Overview

  • Starts with the heart and aortic arch.
  • Key Arteries from Aortic Arch:
    • Brachiocephalic trunk (or artery)
    • Left common carotid artery
    • Left subclavian artery
  • Important: Always specify "artery" to avoid errors.

Brachiocephalic Trunk

  • Divides into:
    • Right subclavian artery
    • Right common carotid artery
  • The split marks the end of the brachiocephalic trunk.

Common Carotid Arteries

  • Both left and right common carotid arteries split.
  • Division leads to:
    • Internal carotid artery
    • External carotid artery
  • The split indicates the end of the common carotid arteries.
  • Common mistakes to avoid:
    • Using just "external carotid" or "internal carotid" without "artery."
    • Mixing common, internal, and external terms (e.g., "external internal").

Carotid Sinus

  • Located at the beginning of the internal carotid artery (sometimes shown as a bulge in diagrams).
  • Contains baroreceptors that detect blood pressure.
  • Mechanism:
    • Stretching indicates high blood pressure.
    • Lack of stretching indicates low blood pressure.

Subclavian Artery and its Transition

  • Tracing Arteries: Important for identification in quizzes and exams; use finger tracing on diagrams.
  • Right Subclavian Artery:
    • Becomes the axillary artery.
  • Transition point: posterior to the clavicle.

Axillary Artery

  • Location: after the clavicle.
  • Prior location of blood: Right subclavian artery.
  • Next locations after the axillary artery: Brachial and deep brachial arteries, which branch off after the axillary artery.
  • Axillary artery ends at its split into the brachial and deep brachial arteries.

Brachial and Deep Brachial Arteries

  • Distinguishing Feature:
    • Deep brachial artery fades (posterior to the bone).
    • Brachial artery does not fade (anterior/superficial to the bone).
  • Brachial Artery branches into the radial and ulnar arteries.

Radial and Ulnar Arteries

  • Brachial artery splits into these.
  • Thumb side: radial artery.
  • Pinky side: ulnar artery.
  • If anatomical position is unclear, remember: ulna is more medial.

Descending Aorta

  • Thoracic Aorta: Portion within the thoracic cavity.
  • Abdominal Aorta: Portion within the abdominal cavity.
  • Landmarks for division:
    • Diaphragm: Separates thoracic and abdominal cavities.
    • Xiphoid Process: Superior indicates thoracic, inferior indicates abdominal.
    • Apex of the Heart: Superior is thoracic, inferior is abdominal (apex rests on the diaphragm).

Common Carotid Artery Branching (Head Region)

  • Divides into:
    • Internal carotid artery
    • External carotid artery

Internal Carotid Artery

  • Distinguishing Feature: Fades in images, indicating it goes inside the skull.
  • Enters the skull through the carotid canal.
  • Function: Supplies blood to the brain.

External Carotid Artery

  • Branches into:
    • Superficial temporal artery
    • Occipital artery
    • Facial artery
    • Maxillary artery
  • Maxillary Artery: Passes through the infraorbital foramen; supplies blood to the cheek area.

Arterial Supply Functions (Head Region)

  • Ophthalmic artery: Supplies the eyes/eye area.
  • Facial artery: Supplies the face.
  • Maxillary artery: Related to the maxilla.
  • Superficial temporal artery: Supplies the side of the head.
  • Occipital artery: Supplies the occipital bone (back of the head).

Vertebral Arteries

  • Course: Surrounded by bone in the neck.
  • Pass through the transverse foramen of cervical vertebrae (only vertebrae in the neck have transverse foramen).
  • Enter the skull through the foramen magnum.
  • Cervical vertebrae: There are seven (breakfast, lunch, and dinner reminder).

Circle of Willis (Arterial Circle)

  • Components (have dots in the picture):
    • Anterior communicating artery
    • Posterior communicating artery
    • Anterior cerebral artery
    • Posterior cerebral artery
    • Internal carotid artery.
  • Function: Ensures continuous blood supply to the brain if one vessel is blocked.

Abdominal Aorta and Branches

  • Diaphragm: Separates thoracic aorta from abdominal aorta.
  • Phrenic Arteries (Superior and Inferior): Supply blood to the diaphragm (phrenic refers to the diaphragm).
  • Celiac Trunk:
    • Branches into: left gastric artery, splenic artery, and common hepatic artery.
  • Superior Mesenteric Artery:
    • Feeds most of the small intestine and proximal large intestine.
  • Suprarenal Arteries:
    • Feed the suprarenal glands (adrenal glands); located on top of the kidneys.
  • Renal Arteries:
    • Supply blood to the kidneys (renal refers to the kidneys).
  • Gonadal Arteries:
    • Supply the gonads (ovaries or testes).
    • Use "gonadal" if sex isn't clear. Specify male/female if sex is evident in the image.
  • Inferior Mesenteric Artery:
    • Feeds the distal large intestine.
  • Lumbar Arteries:
    • Supply the lower back and abdominal wall; typically branch out straight left and right.