Chapter 19 Blood Vessels

Question 1

The Cardiovascular system consists of

Answer 1

the heart and blood vessels

Question 2

There are about ___ miles of blood vessels in the body and the blood vessels are made of ____

Answer 2

1. 60,000 miles

2. Living Cells

Question 3

Arteries

Answer 3

carry blood away from the heart

• narrow lumen compared to veins
• thicker walls than veins

Question 4

Veins

Answer 4

carry blood toward the heart

• wider lumen than arteries
• have thinner walls compared to arteries

Question 5

Capillaries

Answer 5

exchange sites

Question 6

3 Main Parts of The Vascular System

Answer 6

1. Arterial System
2. Capillaries
3. Venous System

Question 7

Arterial System

Answer 7

High Pressure System, thickest layer is tunica media, all layers have more elastic fibers

1. Elastic Arteries- (1-2.5 cm diameter) conducting arteries, has much elastic fibers for stretch + recoil
   ex: aorta, pulmonary arteries
2. Muscular Arteries- (0.3mm- 1cm diameter (smaller)) distributing arteries (distribute blood to specific parts of the body/organs)
   - tunica media cause changes in diameter (vasoconstriction + vasodilation)
   ex: brachial and radial arteries
3. Arterioles (10 micrometers- 0.3 mm (smallest diameter blood vessel)
   - resistance vessels
   - affects blood pressure
   - carry blood to specific capillary beds
   - vasoconstriction + vasodilation to distribute blood to specific capillary beds

Question 8

Arterial System: Elastic Arteries

Answer 8

Size: (1-2.5 cm diameter) widest diameter artery

• conducting arteries
• has much electric fibers for stretch + recoil
  ex: aorta, pulmonary arteries

Question 9

Arterial System: Muscular Arteries

Answer 9

Size: (0.3mm- 1 cm diameter) smaller

• distributing arteries (distributing blood to specific parts of the body/ organs)
• tunica media causes changes in diameter(vasoconstriction + vasodilation)
• ex: brachial + radial arteries

Question 10

Arterial System: Arterioles

Answer 10

Size: (10 micrometers- 0.3mm) smallest diameter blood vessel

• resistance vessels; affects blood pressure
• vasoconstriction + vasodilation to distribute blood to specific capillary beds

Question 11

The Walls of Arteries and Veins have 3 Layers

Answer 11

1. Tunica Interna- endothelial cells
2. Tunica Media- smooth muscle cells
3. Tunica externa- collagen and elastic fibers

Question 12

Blood Flows through the hollow part called the

Answer 12

Lumen

Question 13

Layer of the wall from arteries and veins: Tunica Interna

Answer 13

lined with endothelial cells

-innermost layer

Question 14

Layer of the wall from arteries and veins: Tunica Media

Answer 14

made of smooth muscle tissue

• middle layer
• has ability to change diameter of blood vessel
• causes Vasoconstriction- when the tunica media shorten–> causes lumen to narrow
• causes Vasodilation- lumen widens, increasing blood flow

Question 15

Layer of the wall from arteries and veins: Tunica Externa

Answer 15

made of connective tissue fibers like collagen and elastic fibers
-outermost layer

Question 16

Capillary walls have only 1 layer:

Answer 16

Tunica Interna

Question 17

Capillaries

Answer 17

exchange sites

• medium pressure
• only has layer tunica interna- thin walls
• size: 5-10 micrometers in diameter
• tight junctions join cells together
• Clefts- gaps between neighboring cells; makes capillaries permeable (leaky)

Question 18

3 Types of Capillaries

Answer 18

1. Continuous Capillaries
2. Fenestrated Capillaries
3. Sinusoids

Question 19

Type of Capillary: Continuous Capillaries

Answer 19

• least permeable (less leaky)
• has more tight junctions + clefts
• most common in skin + muscles

Question 20

Type of Capillary: Fenestrated Capillaries

Answer 20

• very permeable
• has pores to allow materials to go through walls of capillaries
• have clefts
• fewer tight junctions
• found in: small intestine and kidney filtration membranes

Question 21

Type of Capillary: Sinusoids

Answer 21

• extremely permeable
• large pores and clefts
• fewest tight junctions
• found in Red bone marrow (where hemopoiesis happens)
• allows whole cells to cross (RBC, WBC , platelets)
• found in spleen (macrophages in spleen that remove damaged RBCs
• found in liver (macrophages remove bacteria)
• big cells move through sinusoids

Question 22

Venous System

Answer 22

• lowest pressure
• have wide lumens
• thin walled
• tunica externa is the thickest layer
• blood reservoirs of the vascular system; holds about 65% of total blood supply (all blood)

Question 23

The Venous System Consists of

Answer 23

1. Venules
2. Veins
3. Venous Sinuses

Question 24

The Venous System: Venules

Answer 24

size: 8 micrometers- 0.1 mm in diameter

- carries blood away from capillary beds; join together to make larger diameter blood vessels to make veins

Question 25

The Venous System: Veins

Answer 25

size: 0.1mm- 4cm in diameter

- valves present in veins prevent backflow from low pressure

Question 26

The Venous System: Venous Sinus

Answer 26

specialized, broad veins supported by surrounding tissue, unique because it has only tunica interna

• has 1 layer- tunica interna
  ex: dural sinus (in brain; drains cerebral spinal fluid CSF and blood from brain)
  ex: coronary sinus (in heart) drains blood from myocardium

Question 27

Anastomosis

Answer 27

(detour)
alternate pathways for blood to reach specific tissue or organ (incase their is a blockage because blood needs to keep flowing and moving to the heart)