Blood Vessels Flashcards
Layers of the blood vessel wall
- t. intima (endothelium): loose CT + simple squamous epi.
- t. media: smooth muscle (not cardiac), may have elastin
- t. externa (adventitia) : fibrous CT with elastin
Arteries
- distinguishing features: relatively small diameters (compared to veins), thick t. media, abundant elastin
- function of arteries: carry blood away from the heart to H and B tissues (not always oxygenated)
Veins vs. Arteries
- 1 systemic artery leaves the L ventricle vs. 3 systemic, major veins enter the R atrium
- Large and medium size arteries –> deep locations vs. “superficial veins” underneath the skin
- Several parallel veins take the place of a single larger vein (“venous plexuses”)
Veins
• Distinguishing features: relatively large diameters, thin t. media, thick t. externa,
large veins have valves especially in legs
• Function of veins: carry blood from Head and Body tissues back to the heart (not always deoxygenated)
• At any moment at rest 50-70% of your blood is in your veins
Capillaries
- structure: endothelium (t. intima) only (keeps CVS closed)
- function: exchange of substances with Head and Body tissues
Regions of the aorta (3)
- ascending: the 1st section, exits the LV
- arch: bends to the left and posteriorly
- descending: passes blood in an inferior direction
– thoracic aorta: the descending aorta superior to the diaphragm
– abdominal aorta: the descending aorta inferior to the diaphragm
2 branches from the ascending aorta
- Coronary arteries: supply the myocardium
- Rt. Coronary branches to the marginal artery and posterior interventricular artery
- Lt. Coronary branches to the anterior interventricular a. and circumflex a.
Cardiac veins
- Drain capillaries of the myocardium
- Supports the myocardium of the heart (not endo- or pericardium.
- Endocardium uses the blood in the heart chambers
- Pericardial aa. arise from other sources
What the aortic arch supplies
the head, neck, upper limbs, and anterior chest wall
What the brachiocephalic branches to
rt. subclavian a. and rt. common carotid a.
Lt. common carotid a.
Branches to internal and external carotid a.
Lt subclavian a. passes under clavicle toward the left arm
Branches to: • vertebral a. • thyrocervical a. • costocervical a. • internal thoracic a. • axillary a.
Superior Vena Cavae
- superior: formed by 2 brachiocephalic veins and azygos system of veins
- brachiocephalic veins (2): formed by internal jugular and subclavian veins
- (external jugular veins empty into the subclavian veins)
From the thoracic aorta
• posterior intercostals arise from the thoracic aorta
– anterior intercostals arise from the internal thoracic a. or costal cervical a
• bronchial, esophageal, and superior phrenic arteries
From the abdominal aorta (abdominal region)
- inferior phrenic arteries
- celiac trunk; quickly branches to (3): hepatic, lt. gastric, splenic
- other gastric arteries: lt. gastroepiploic a. and rt gastric
- gonadal arteries either spermatic or ovarian a.
- inferior mesenteric artery other areas of the colon not supplied by the superior mesenteric a.
- lumbar arteries muscles and spinal cord of lumbar region