Blood Vessels and Circulation Flashcards
1
Q
General characteristics of blood vessels… (5)
A
- Closed circuit of tubes
- Arteries carry blood away from the heart
- Capillaries are exchange vessels
- Veins return blood to the heart
- Oxygen does not distinguish arteries from veins
2
Q
Summary/Path of circulation
A
- Heart
- Arteries
- Arterioles
- Capillaries
- Venules
- Veins
- Heart
3
Q
- Smooth surface for blood flow
- Simple squamous epithelium
A
Endothelium
4
Q
The connective tissue in endothelium provides…
A
Provides elasticity to withstand the blood pressure changes
5
Q
The smooth muscle in blood vessel tissues control…
A
- Vasoconstriction
2. Vasodilation
6
Q
What are the 3 layers of the blood vessel?
A
- Tunica intima
- Tunica media
- Adventitia (Tunica externa)
7
Q
Characteristics of the Tunica Intima… (3)
A
- Inner most
- Endothelium on top of connective tissue
- Internal elastic membrane
8
Q
Functions of the Tunica Intima (3)
A
- Separates blood flow from vessel wall
- Prevents blood clotting
- Helps regulate blood pressure
9
Q
Characteristics of the Tunica Media (3)
A
- Middle
- Bulk of wall
- Smooth muscle and elastic CT
10
Q
Characteristics of Adventitia (Tunica Externa)
A
- Outer most
- Thin
- Made of CT, elastic and collagenous fibers
- Attaches artery to surrounding tissues
- Contains vasa vasorum
11
Q
What is vasa vasorum?
A
Blood vessels within the Tunica externa because the layer is so thick it needs its own blood supply
12
Q
Characteristics of Arteries (2)
A
- Strong and elastic
2. Subdivided into arterioles
13
Q
Artery differences from veins (3)
A
- Artery wall is thicker
- Artery lumen appears smaller
- Endothelium of artery can not contract
14
Q
Types of Arteries (2)
A
- Elastic
2. Muscular
15
Q
Characteristics of Elastic Arteries (4)
A
- Large diameter
- In areas of high pressure
- Media= high % elastic tissue and less smooth muscle
- Ex. Pulmonary truck, aorta, carotid, subclavian, common iliacs
16
Q
Characteristics of Muscular Arteries (4)
A
- Large to small diameter
- Carry blood to skeletal muscles and organs
- Media= lots of smooth muscle, less elastic tissue
- Ex. Femoral, carotids, brachialis, mesenterics
17
Q
Characteristics of Arterioles (5)
A
- Microscopic continuations of arteries
- Small diameter
- Adventitia is thin
- No external elastic membrane
- No vasa vasorum
18
Q
Characteristics of Capillaries (3)
A
- Only intima
- Basement membrane
- Simple squamous epithelium - Very thin
- Variable permeability
19
Q
What are the materials exchanged in capillaries? (3)
A
- Nutrients
- Dissolved gases
- Wastes
20
Q
How is capillary permeability maximized…? (3)
A
- Thin wall
- Low BP
- Slow blood flow
21
Q
Mechanisms of permeability (4)
A
- Diffusion across endothelial cells
- Diffusion through gaps between endothelium
- Diffusion through pores
- Vesicular transport with pinocytes
22
Q
What diffuses across endothelial cells?
A
- Lipids
2. Gases
23
Q
What diffuses through gaps between endothelium?
A
- Water
2. Small solutes
24
Q
What diffuses through pores?
A
- Water
2. Larger solutes
25
What diffuses through vesicular transport with pinocytes?
Large bound solutes
26
Characteristics of Continuous capillaries (3)
1. Tight junctions
2. Desmosomes
3. Pinocytes
27
How do continuous capillaries allow movement? (2)
1. Passive Transport
| 2. Active Transport
28
Where are continuous capillaries located? (3)
1. CNS
2. Skeletal muscle
3. Lungs
29
Characteristics of Fenestrated Capillaries (2)
1. Swiss cheese appearance
| 2. Have pores
30
What do fenestrated capillaries allow movement of?
1. Peptides
| 2. Small proteins
31
Where are Fenestrated Capillaries located?
1. Kidneys
2. Intestines
3. Endocrine Glands
4. Choroid Plexus
32
Characteristic of Sinusoid Capillaries
Specialized for max exchange by...
- Large intercellular gaps
- Pores
- Discontinuous basement membrane (allows cells to enter or exit)
33
Where are Sinusoid Capillaries located?
1. Spleen and bone marrow
| 2. Liver and adrenal glands
34
A network of interconnected capillaries
| -Derived from arterioles
Capillary beds
35
What manages blood flow to bed?
Precapillary Sphincters
36
These provide a direct connection through the bed
| -Leads through a thoroughfare channel
Metarterioles
37
2 types of Anastomoses
1. Collateral Arteries
| 2. Arteriovenous Anastomosis
38
The 2 arteries fuse
- Twice as much blood supplies in the arteries
- Found in areas with high oxygen demands
Collateral Arteries
39
Direct connection between arteriole and venule
| -Where bloodflow may be hindered by posture
Arteriovenous Anastomosis
40
- Smallest veins that collect blood from capillaries
- Can lack a media
- Scatter, minimal amount of smooth muscles occasionally
Venules
41
Characteristics of Medium sized veins (6)
- 2-9 mm in diameter
- Thin media
- Few smooth muscle fibers
- Thick adventitia
- Low BP
- Valves
42
Characteristics of large sized veins (6)
- Great veins (superior/inferior vena cava and their tributes
- Thin media
- Thick adventitia
- Low BP
- Contains valves
43
- Flap like structures projecting inward
- Folds of media
- Found in extremities
Venous Valves
44
Veins have low BP so ____ help prevent back flow of blood
Valves
45
Movement of blood through veins for the movement of limbs and contraction of muscles
Skeletal muscle pump
46
Expansion of the thoracic cavity
Thoracoabdominal pump
47
Characteristics of Blood distribution
- Uneven
- Oxygenated blood in the heart, arteries, and capillaries = 1/3
- Deoxygenated, venous blood= 2/3 of blood
- Known as blood reservoir
- Veins contract during blood loss
48
Characteristics of the Pulmonary Circuit
1. Deoxygenated blood goes to the lungs from right ventricle
2. Oxygenated in alveolar capillaries of the lungs
3. Brought to the left atrium, then left ventricle
4. Veins=oxygenated blood
5. Arteries= deoxygenated blood
49
Characteristics of the Systemic Circuit (5)
1. Oxygenated blood goes from the left ventricle to the body
2. Deoxygenation occurs in systemic capillaries
3. Brought to the right atrium, then the right ventricle
4. Veins= deoxygenated
5. Arteries= oxygenated
