Chapter 6 Vessels

Question 1

Role of Blood Vessels

Answer 1

dynamic structures that control the delivery of blood to and from body tissues

Question 2

Role of Arteries

Answer 2

Carry oxygen rich blood away from heart

Question 3

3 types of arteries

Answer 3

• elastic arteries
• muscular arteries
• Arterioles

Question 4

Which artery is an exception and has oxygen poor blood

Answer 4

Pulmonary artery

Question 5

What are Capillaries?

Answer 5

thinnest type of blood vessel involved in gas exchange

Question 6

Role of Veins

Answer 6

Return oxygen poor blood to the heart

Question 7

3 types of veins

Answer 7

-venules
-small veins
-large veins

Question 8

which vein is an exception and contains oxygen rich blood?

Answer 8

Pulmonary veins

Question 9

Largest volume of blood is located in the….

Answer 9

Veins and venules about 60%

Question 10

3 layers of tissues that make up blood vessels

Answer 10

• Tunica intima
  -Tunica media
  -Tunica externa

Question 11

Describe Tunica intima

Answer 11

• inner layer
• direct contact w blood
• similar to membrane made of one layer of epithelial cells and thin layer of connective tissue
  ARTERIES ONLY- contain an internal elastic membrane

Question 12

Describe Tunica media

Answer 12

• smooth muscle layer
• ARTERIES ONLY- elastic fiber membrane
• smooth muscle controls vasomotion (contraction or relaxation of muscle) especially in arteries.

Question 13

Contraction of tunica media is also called

Answer 13

Vasoconstriction

Question 14

Relaxation of tunica media is also called

Answer 14

Vasodilattion

Question 15

Describe Tunica externa

Answer 15

-Outermost layer
-made up of connective tissue with mainly collagen
-anchors vessel to surrounding tissue
- Vasa Vasorum- vessels of the vessels (outer layer needs own blood supply.

Question 16

which artery can withstand the most pressure?

Answer 16

Elastic because it contains an internal elastic layer and needs to be able to withstand pressure because the heart is constantly ejecting blood .

Question 17

where are elastic arteries located?

Answer 17

Proximal to heart

Question 18

Role of Elastic arteries

Answer 18

act as pressure reservoirs (expand and recoil as heart ejects blood)

Question 19

Role of Muscular arteries

Answer 19

-Deliver blood to specific body organs
- more muscle in the tunica media is responsible for vasoconstriction

Question 20

Role of Arterioles

Answer 20

• smallest artery ( many only have 2 layers)
• feed into capillary beds
  -Vasoconstriction and vasodilation control blood flow into capillary beds
  -blood within arterioles face resistance also called resistance vessels ( vessel diameter decreases blood flow decreases too)

Question 21

Which artery has
the thickest tunica
media relative to
its lumen size?

Answer 21

Muscular artery

Question 22

Describe what are aneurysms

Answer 22

balloon like bulge in the wall of a blood vessel due to weakened arterial walls.

Question 23

What happens if theres less collagen in elastic arteries?

Answer 23

• weakened blood vessels (spontaneous bruising)
  -swollen gums/ loss of teeth.

Question 24

Role of capillaries

Answer 24

connect arteriole and venules and are the major site of exchange between blood and tissues
- only tunica intima is present to promote rapid diffusion of material from blood into tissue and vice versa.

Question 25

The flow of blood through capillary beds is controlled by

Answer 25

sphincter muscle cells

Question 26

what determines if the capillary beds are open or closed?

Answer 26

contraction of sphincters

Question 27

two major type of capillaries

Answer 27

1.Continuous 2. Fenestrated

Question 28

describe Continuous capillary

Answer 28

-Most common -least permeable -wall consists of single endothelial cell thick -the cells overlap to make intercellular clefts where molecules can travel through diffusion. ex skin, lung and muscle

Question 29

if intercellular clefts were close the permeability of small molecules via diffusion would...

Answer 29

decrease

Question 30

Describe fenestrated capillaries

Answer 30

- have pores in endothelial cells = increase permeability - more permeable - found in locations where rapid transport is important like kidneys and small intestines

Question 31

describe Sinusoidal capillaries

Answer 31

- Most permeable -large fenestration and incomplete basement membrane -only found in limited locations like the liver and spleen

Question 32

order of capillaries in order of least permeable to most permeable

Answer 32

-Continuous, fenestrated, sinusoidal

Question 33

description of veins

Answer 33

veins are blood reservoirs (pool blood due to low pressure) that returns blood to heart

Question 34

order of blood drainage from capillary beds to heart

Answer 34

capillary beds --> venules --> medium sized veins--> large veins ---> heart

Question 35

Backflow valves are made of what and what do they do...

Answer 35

folds of tunica intima and ensure one way flow of blood

Question 36

Describe muscular pump on veins

Answer 36

veins rely on compression from nearby skeletal muscle and valves to push blood against gravity

Question 37

"normal" blood flow order to and from heart

Answer 37

Heart---> artery --> capillary (gas & nutrient exchange) --> vein ---> heart

Question 38

two exceptions of regular blood flow

Answer 38

1. Portal system- blood travels to two capillary beds before returning to heart 2. Anastomosis: allternating blood routes to bypass a capillary or several vessels that lead to the same location

Question 39

Types of anastomosis: Arterial

Answer 39

located around joints, allow blood to flow no matter which position the joint is in

Question 40

Types of anastomosis: venous

Answer 40

backup pathway for blood flow if a blood vessel becomes blocked

Question 41

Types of anastomosis: arteriovenous

Answer 41

common in skin, shunt blood directly into the venous plexus without it passing through capillaries