PSIO Lab 2

Blood Vessels

Describe the general appearance of arteries and veins

Arteries: Thick walls, small lumens. Rounded.

Veins: Thin walls, large lumens. Flattened.

What are the three distinct tissue layers in both arteries and veins? (superficial to deep)

1. Tunica externa

2. Tunica media

3. Tunica intima

Describe the tunica externa in both arteries and veins

Arteries: Usually thinner than media (except in big vessels). Collagenous/elastic fibers. Vasa vasorum are present on large vessels.

Veins: Thickest layer in veins. Collagenous/elastic fibers, some smooth muscle. Vasa vasorum are present in large vessels

Describe the tunica media in both arteries and veins

Arteries: Thickest layer in arteries. External elastic lamina → Smooth muscle (deep)

Veins: Thinner than externa. Smooth muscle/collagenous fibers. Vasa vasorum in large vessels. No external elastic membrane.

Describe the tunica intima in both arteries and veins

Arteries: Endothelium appears wavy. Basement membrane. Internal elastic membrane. (superficial)

Veins: Endothelium appears smooth. No internal elastic membrane.

Label this diagram of the internal blood vessel

What are vasa vasorum?

Small networks of blood vessels that supply the tunica externa (arteries and veins) and tunica media (veins)

Nervi vasorum

Nerves that innervate the tunica externa

What are the three types of arteries? And what are some characteristics?

1. Elastic arteries: found closest to the heart/thickest walls/most elastic

2. Muscular arteries: Distribute blood to a vast network of arterioles, aka distributing artery

3. Arterioles: very small arteries that lead to a capillary

What are capillaries? What do they do?

• Microscopic channels that supply blood to tissues throughout the body (perfusion)

• exchange gas/other substances through blood and surrounding interstitial fluid

What is perfusion?

The distribution of blood to the tissues

What must be true about capillaries that allows them to allow substances to pass through?

Their walls must be “leaky”

What are the three major types of capillaries? What are they categorized based on?

• Categorized based on leakiness

  • Continuous capillaries (least leaky)

  • Fenestrated capillaries

  • Sinusoid capillaries

Blood moves out of ____ to enter the venous circulation

capillary beds

What is the purpose of valves in large veins?

Promote unidirectional flow to the heart; prevent backflow toward capillaries

Which is more distensible? Arteries or veins? Why?

Veins because they store higher amounts of blood at any given time;

• Adjusts the contraction of veins

• Remember: thinner walls, larger lumens

What is a venule? What do multiple venules make up?

An extremely small vein

• Multiple venules join together = vein

Postcapillary venule

Multiple capillaries join together to form a postcapillary venule exiting the capillary bed

Fill out this function chart

Label this diagram of an artery

1. Tunica Externa

2. Tunica Media

3. Tunica interna

Anastomosis

Vessel that allows for alternate route of blood flow

Trunks

Large, short vessels that immediately branches

Portal

Vessel that connects two capillary beds in series

Vasoconstriction

Contraction of smooth muscle, smaller lumen

• INCREASES blood pressure

Vasodilation

Relaxation of smooth muscle, bigger lumen

• DECREASES blood pressure

The cerebral arterial circulation (circle of willis) is an example of what?

Anastomosis

The brachiocephalic trunk branches into which two vessels?

Right subclavian artery and right common carotid artery

What are the three major branches of the aortic arch?

1. Brachiocephalic artery (→ right common carotid/right subclavian)

2. Left common carotid artery

3. Left subclavian artery

Where do the R/L subclavian and R/L carotid arteries supply blood?

Subclavian: arms

Carotid: head and brain

What do the R/L subsclavian arteries branch into?

Vertebral arteries

What do the R/L Common Carotid arteries branch into? To where do these arteries supply blood?

1. External carotid artery: Scalp and R/L head

2. Internal carotid artery: brain and cerebral circuit

Where do mesenteric arteries supply blood?

Intestines

List the three branches of the Celiac trunk

1. Common hepatic artery

2. Splenic artery

3. L Gastric artery

Name the blood vessels that will receive blood directly from the right radial artery

Right deep/superficial palmar arches

Name the blood vessels that will receive blood directly from the left median cubital vein

Cephalic/Basilic vein

True or false: The anterior tibial artery supplies the medial/lateral plantar arteries with blood

FALSE! The anterior tibial artery supplies the dorsal arteries of the feet

Name the blood vessel that will receive blood directly from the Right posterior tibial veins

Right popliteal vein

What is the hepatic portal system?

A system of capillaries that allows nutrients and wastes to travel to the liver for processing

True or false: Portal systems begin in capillaries and end in their target organs

False! Begin in capillaries and end in capillaries