Principles of Anatomy: Blood Vessels

Distribution of blood

• Systemic circuit > pulmonary circuit

• Veins> arteries> heart> capillaries

Distribution changes due to autonomics (exercise, being nervous, etc)

arteriole

• smallest of arteries that delivers blood to capillaries

• Higher pressure

venule

smallest of veins that collects blood from the capillaries and sends it back to heart via veins

simplest pathway

simplest, most common, one capillary bed

portal system

• two capillary beds right after another

• common in digestive systems (hepatic portal system, liver)

arteriovenous anastomosis

blood flows from an artery directly into a vein, no capillary bed

venous anastomoses

one vein empties directly into another

arterial anastomoses

two or more arteries merge into one

vessel wall

Turnica Interna- innermost

• simple squamous epithelium

Turnica Media- middle

• smooth muscle (controlled by ANS)

  • contraction= vasoconstriction

    • decrease in lumen diameter, increase in blood pressure

Tunica externa- outermost

• Connective tissue

Veins

get gradually larger in diameter

Medium veins-

• tunica interna invades lumen to create valves

• valves allow one way blood flow

• THIN tunica media compares to arteries because they don’t propel blood as well

arteries

get gradually smaller in diameter

• THICK tunica media to pump blood forward all throughout body

Arteriole

• have sphincters that open and close lumen

• smooth muscle cause vasoconstriction to limit blood entering capillary beds

  • precapillary sphincters dilated= capillaries are abundantly supplied with blood

  • precapillary sphincters closed= blood bypasses capillaries

arteries supplying upper limb

1. aortic arch

2. brachiocephalic trunk

3. subclavian artery

4. axillary artery

5. brachial artery

6. radial/ulnar artery

7. palmar arches

arteries supplying lower limbs

1. abdominal aorta

2. common iliac arteries

3. external iliac arteries

4. femoral arteries

5. popliteal arteries

6. anterior/posterior tibial arteries

7. dorsal pedal artery

veins of upper limbs

1. radial/ulnar veins

2. brachial vein

3. axillary vein

4. subclavian vein and internal jugular vein (drains head)

5. brachiocephalic vein

6. superior vena cava

*internal jugular and subclavian join to form brachiocephalic and right and left brachiocephalic flow into SVC

veins of lower limbs

1. anterior/posterior tibial veins

2. popliteal vein

3. femoral vein

4. external iliac veins

5. common iliac veins

6. inferior vena cava

arterial pressure points

• vessels used to palpate pulse

• points you can apply pressure to to reduce bleeding

• when distal pulses are hard to feel, could be a sign that tissues aren’t being profused= amputation