The Cardiovasculary System: Blood Vessels And Circulation Flashcards
(114 cards)
1
Q
What do arteries do?
A
Carry blood away from the heart/oxygenated
Oxygenated except for pulmonary circulation and umbilical vessels of a fetus
2
Q
What is the primary function of capillaries?
A
Contact tissue cells and directly serve cellular needs
The capillaries allow the diffusion of nutrients in and out of tissues
3
Q
What do veins do?
A
Carry blood toward the heart/deoxygenated
Have valves to help direct the flow
4
Q
Describe the flow of blood vessels.
A
They are loops starting with arteries ending in veins getting thinner and less pressure
5
Q
True or False: All arteries carry oxygenated blood.
A
False
Pulmonary circulation and umbilical vessels of a fetus carry deoxygenated blood
6
Q
What are the three layers of arteries?
A
- Tunica intima → covered by endothelium
- Tunica media → muscular layer
- Tunica externa
7
Q
What are the three types of arteries?
A
- Elastic (Conduction) → allows for expansion and recoil
- Muscular (Distributing) → actively change diameter (like we workout)
- Arterioles (small arteries) → Control the blood flow into tissues
8
Q
What are the three types of capillaries?
A
- Continuous
- Fenestrated
- Sinusoidal
9
Q
What characterizes continuous capillaries?
A
They have tight junctions and are found in skin and muscles.
10
Q
What characterizes fenestrated capillaries?
A
They contain pores for gases and are very small, found in the kidneys.
11
Q
What characterizes sinusoidal capillaries?
A
They allow large molecules to pass and are found in the liver, bone marrow, and spleen.
12
Q
What connects the terminal end of an arteriole to a venule?
A
Capillaries
13
Q
What are capillary beds?
A
Networks of capillaries that connect arterioles to venules.
14
Q
What are the two ends of a capillary?
A
They have an arterial end and a venous end.
15
Q
What are veins?
A
Veins are blood vessels that carry blood towards the heart.
16
Q
What are the characteristics of vein walls?
A
Veins have thin walls.
17
Q
What role do valves play in veins?
A
Valves help keep blood flowing to the heart and prevent backflow.
18
Q
What are venules?
A
Venules are the smallest veins that drain into larger veins.
19
Q
What is SmartArt?
A
SmartArt is a feature used for creating diagrams and visual representations of information.
20
Q
What is the blood flow through capillaries?
A
Blood flow through capillaries is slow and intermittent.
21
Q
Why is blood flow through capillaries slow and intermittent?
A
Due to low pressure gradient along the vessel and the opening and closing of sphincters.
22
Q
What is the primary function of capillaries?
A
Capillaries are the site of all exchange between blood and tissues.
23
Q
How does simple diffusion occur in capillaries?
A
Simple diffusion occurs from high to low concentration, allowing O2 into tissues and CO2 out into blood.
24
Q
How do lipid soluble substances move through capillaries?
A
Lipid soluble substances diffuse directly through endothelial membranes.
25
How do water soluble substances move through capillaries?
Water soluble substances pass through clefts between cells.
26
What is SmartArt?
A feature used to create diagrams and visual representations of information.
27
What are the main forces determining blood flow direction in capillaries?
Hydrostatic pressure and colloid osmotic pressure.
28
What is capillary hydrostatic pressure?
The pressure that pushes fluid into the tissues.
29
What does the hydrostatic pressure of interstitial fluid do?
It pushes fluid back into the capillary.
30
What is colloid pressure?
Also known as oncotic pressure, it is caused by plasma proteins that draw water back to the vessel.
31
What is the Frank Starling Law of Capillaries?
It describes how water and larger ions move in and out of capillaries via bulk flow.
32
What is SmartArt?
SmartArt is a feature used for creating visual representations of information.
33
What does Net Filtration Pressure (NFP) represent?
NFP represents the overall forces (pressures) that determine the movement of water in or out of the capillary.
34
What happens when NFP is positive?
When NFP is positive, water moves out of the capillary at the arteriole (arterial) end.
35
What happens when NFP is negative?
When NFP is negative, water moves into the capillary at the venous end.
36
How much fluid is not returned to the capillary?
A small amount of fluid (3L/day) is not returned to the capillary.
37
What happens to the fluid not returned to the capillary?
The fluid not returned to the capillary is drained by the lymphatic system.
38
What is blood pressure?
Force per unit area exerted on the wall of a blood vessel by the blood.
## Footnote
Expressed in mm Hg.
39
How is blood pressure measured?
Measured as systemic arterial BP in large arteries near the heart.
40
What causes blood to flow?
Pressure Gradient.
41
What are the main factors influencing blood pressure?
1. Cardiac output (CO)
2. Peripheral resistance (opposition to blood flow)
3. Blood volume.
42
What is blood pressure?
Force per unit area exerted on the wall of a blood vessel by the blood.
## Footnote
Expressed in mm Hg.
43
How is blood pressure measured?
Measured as systemic arterial BP in large arteries near the heart.
44
What causes blood to flow?
Pressure Gradient.
45
What are the main factors influencing blood pressure?
1. Cardiac output (CO)
2. Peripheral resistance (opposition to blood flow)
3. Blood volume.
46
What is the range of capillary blood pressure?
15 to 35 mm Hg
47
Why is low capillary pressure desirable?
High BP would rupture fragile, thin-walled capillaries
48
True or False: High capillary blood pressure is safe for capillaries.
False
49
Fill in the blank: Capillary blood pressure ranges from _______.
15 to 35 mm Hg
50
What could happen if capillary blood pressure is too high?
Rupture of fragile, thin-walled capillaries
51
What is systemic pressure?
Systemic pressure is what health professionals use to measure arterial blood pressure.
## Footnote
Normal value = 120/80
52
Where is systemic pressure highest?
Systemic pressure is highest in the aorta.
53
How does systemic pressure change throughout the pathway?
Systemic pressure declines throughout the pathway.
54
What is the pressure in the right atrium?
The pressure in the right atrium is 0 mm Hg. If it is higher, it relaxes the atrial reflex.
55
Where does the steepest drop in pressure occur?
The steepest drop in pressure occurs in arterioles.
56
What is systemic pressure?
Systemic pressure is what health professionals use to measure arterial blood pressure.
## Footnote
Normal value = 120/80
57
Where is systemic pressure highest?
Systemic pressure is highest in the aorta.
58
How does systemic pressure change throughout the pathway?
Systemic pressure declines throughout the pathway.
59
What is the pressure in the right atrium?
The pressure in the right atrium is 0 mm Hg. If it is higher, it relaxes the atrial reflex.
60
Where does the steepest drop in pressure occur?
The steepest drop in pressure occurs in arterioles.
61
What is the change in venous blood pressure during the cardiac cycle?
Changes little during the cardiac cycle
62
What is the typical pressure gradient in venous blood pressure?
About 15 mm Hg
63
Why is venous blood pressure considered low?
Due to cumulative effects of peripheral resistance
64
65
What is the role of baroreceptors in the carotid sinus?
They protect the brain.
66
What is the function of baroreceptors in the aortic arch?
They maintain systemic circulation.
67
Where are chemoreceptors located in relation to the respiratory system?
In the same locations as baroreceptors (carotid sinus and aortic arch).
68
What is the pathway of baroreceptor signaling?
Baroreceptors → Vasomotor Control Center → Vascular Muscles.
69
What actions do vascular muscles perform in response to baroreceptor signaling?
They undergo dilation or constriction.
70
What is the Direct Renal Mechanism?
It alters blood volume independently of hormones.
71
What happens when blood pressure (BP) or blood volume increases?
The kidneys eliminate more urine, thus reducing BP.
72
What occurs when blood pressure (BP) or blood volume decreases?
The kidneys conserve water, and BP rises.
73
What is the role of the kidney in the Renin-Angiotensin Mechanism?
The kidney releases renin when blood pressure is low
74
What does renin produce in the Renin-Angiotensin Mechanism?
Angiotensin II
75
How does Angiotensin II affect blood pressure?
It increases blood pressure
76
What is a direct action of Angiotensin II?
It is a potent vasoconstrictor
77
What is an indirect action of Angiotensin II?
Secretion of aldosterone
78
What effect does aldosterone have on renal function?
It increases renal reabsorption of Na+ and reduces urine formation
79
What hormone does Angiotensin II stimulate the release of?
ADH (Antidiuretic Hormone)
80
Fill in the blank: When blood pressure is too low, the kidney releases _______.
renin
81
True or False: Angiotensin II only increases blood pressure through direct vasoconstriction.
False
82
What method is used to measure systemic arterial blood pressure?
The auscultatory method using a sphygmomanometer.
83
How is pressure increased in the cuff during blood pressure measurement?
Pressure is increased until it exceeds systolic pressure in the brachial artery.
84
What is done after the cuff pressure exceeds systolic pressure?
Pressure is released slowly while the examiner listens for sounds of Korotkoff with a stethoscope.
85
What is blood flow?
Volume of blood flowing through a vessel, an organ, or the entire circulation in a given period.
86
How is blood flow measured?
Measured as ml/min.
87
What is blood flow equivalent to in the vascular system?
Equivalent to cardiac output (CO) for the entire vascular system.
88
How does blood flow behave when at rest?
Relatively constant when at rest.
89
How does blood flow vary among individual organs?
Varies widely through individual organs, based on needs.
90
What is resistance in the context of circulation?
Opposition to flow, a measure of the amount of friction blood encounters.
91
Where is resistance generally encountered?
In the peripheral systemic circulation.
92
What are the three important sources of resistance?
1. Blood viscosity
2. Total blood vessel length
3. Blood vessel diameter (arteria)
93
How do blood viscosity and total blood vessel length change?
They remain fairly constant but can change over a period of time.
94
How does blood vessel diameter change?
It can be changed easily.
95
What are the major determinants of peripheral resistance?
Small-diameter arterioles are the major determinants of peripheral resistance.
96
What can dramatically increase resistance in blood vessels?
Abrupt changes in diameter or fatty plaques from atherosclerosis dramatically increase resistance.
97
What effect do abrupt changes in diameter or fatty plaques have on blood flow?
They disrupt laminar flow and cause turbulence.
98
What is blood flow directly proportional to?
Blood pressure gradient
## Footnote
An increase in pressure leads to an increase in blood flow.
99
What happens to blood flow if peripheral resistance increases?
Blood flow decreases
## Footnote
This reflects the inverse relationship between blood flow and resistance.
100
What is more important in influencing local blood flow?
Resistance
## Footnote
Resistance can be easily changed by altering blood vessel diameter.
101
Blood flow is inversely proportional to _______.
Peripheral resistance
102
If blood pressure increases, what happens to blood flow?
Blood flow speeds up
103
What can easily change resistance in blood flow?
Altering blood vessel diameter
104
What is perfusion?
The flow of blood through a tissue or an organ
## Footnote
Perfusion is essential for delivering oxygen and nutrients while removing carbon dioxide and waste products.
105
What is the primary purpose of perfusion?
To deliver oxygen and nutrients, and to remove carbon dioxide and waste products
106
At rest, how much blood does the heart pump per minute in men?
About 5.25L/min
107
At rest, how much blood does the heart pump per minute in women?
About 4.25L/min
108
True or False: Perfusion is only concerned with delivering oxygen.
False
109
Fill in the blank: The flow of blood through a tissue or an organ is known as _______.
perfusion
110
What is the fastest blood flow location?
The fastest blood flow occurs in the aorta.
111
Where is blood flow slowest?
Blood flow is slowest in capillaries.
112
How does blood flow change in veins?
Blood flow picks up speed again in venules and veins.
113
What regulates blood flow to tissues?
Blood flow to each tissue is regulated depending on the actual needs of the tissue.
114
What is autoregulation?
Autoregulation is the process of adjusting the diameter of the arteries feeding a particular tissue.
