Cardiovascular System - Blood Vessels Flashcards
Exam 2
1
Q
Varicose Veins
A
dilated and painful veins due to incompetent (leaky) valves; Can be caused by prolonged standing in one position, pregnancy, obesity
2
Q
Hemodynamics
A
the means by which blood flow is altered and distributed and by which blood pressure is regulated
3
Q
Angiogenesis
A
the growth of new blood vessels
- important process in fetal and postnatal
4
Q
Tumor Angiogenesis Factors (TAFs)
A
proteins secreted by malignant tumors that stimulate blood vessel growth to nature the tumor cells
5
Q
Blood Vessels
A
form a closed system of tubes that carry blood away from the heart, transport it to the tissues of the body, and then return it to the heart
6
Q
Arteries
A
carry blood from the heart to the tissues
7
Q
Arterioles
A
very small arteries that deliver blood to capillaries
- through vasodilation and vasoconstriction, play a key role in regulating blood flow from arteries into capillaries and in altering arterial blood pressure
8
Q
Capillaries
A
- the site of substance exchange between the blood and body tissues. Usually connects arterioles and venules
- found near almost every cell in the body
9
Q
Venules
A
drain blood from capillaries into larger veins
10
Q
Veins
A
convey blood from the tissues back to the heart
11
Q
Vaso Vasorum
A
-“Vessels of Vessels”
- network of small blood vessels that supply nutrients to the walls of the large blood vessels
12
Q
Walls of the Artery
A
Tunica Interna, Tunica Media, Tunica Externa
13
Q
What are the functional properties of arteries?
A
Elasticity and Contractility (maintained in the tunica media)
14
Q
Elasticity
A
- allows arteries to accept blood under great pressure from the contraction of the ventricles and send it through the system
- due to elastic tissue in the tunica interna and media
15
Q
Contractility
A
- allows arteries to increase or decrease lumen size and to limit bleeding from wounds
- due to the smooth muscle in the tunica media
16
Q
Elastic Arteries
A
- large arteries with more elastic fibers and less smooth muscle
- able to receive blood under pressure and propel it onward
17
Q
What are Elastic Arteries also called?
A
Conducting Arteries b/c conduct blood from the heart to medium-sized muscular arteries
18
Q
Muscular Arteries
A
have a large amount of smooth muscle in their walls and distribute blood to various parts of the body
19
Q
Vasoconstriction
A
decrease in the size of the lumen of a blood vessel
20
Q
Vasodilation
A
increase in the size of the lumen of a blood vessel
21
Q
Microcirculation
A
flow of blood through the capillaries
22
Q
What is the primary function of capillaries?
A
permit the exchange of nutrients and wastes between the blood and tissue cells through interstitial fluid
23
Q
What composes the layer of the capillaries?
A
endothelium and a basement membrane (single layered)
24
Q
What is the function of the smooth muscle in the capillary walls?
A
regulate the flow of blood through them
25
Precapillary Sphincters
rings of smooth muscle fibers (cells) that regulate blood flow through true capillaries
26
What are the three types of capillaries?
| Provide Definitions
- Continuous: little or no space between squamous cells (found in skin, muscles, lungs, brain)
- Fenestrated: found in Glomerulus and Bowman's Capsule (Renal Corpuscle) of the Kidneys
- Sinusoids: widest openings (found in the liver)
27
How do veins differ from arteries?
- veins have thinner tunica interna and media and a thicker tunica externa
- veins have less elastic tissue and smooth muscle and therefore thinner-walled
- contain valves to prevent backflow of blood
28
Vascular (Venous) Veins
2 examples where located
- veins with very thin walls with no smooth muscle to alter their diameters
- Ex: brain's superior sagittal sinus
- Ex: coronary sinus of the heart
29
What can weak valves cause?
Varicose Veins (blood pools, causing enlarged veins)
30
What are the most common sites for Varicose Veins?
- esophagus
- superficial veins of the lower limbs
- veins in the anal canal (hemorrhoids)
31
What are the treatment options for varicose veins in the lower limbs?
- sclerotherapy
- radio frequency endovenous occlusion
- laser occlusion
- surgical stripping
32
Anastomoses
- the union of the branches of two or more arteries supplying the same region
- provide alternate routes for blood to reach a tissue or organ
- can also consists of two veins or a vein and an artery
33
Collateral Circulation
the alternate flow of blood to a body part through an anastomosis
34
End Arteries
- arteries that do not anastomose
- occlusion of an end artery interrupts the blood supply to a whole segment of an organ, producing necrosis (death) of that segment
35
Blood Reservoirs
- the systemic veins and venules that contain the largest portion of the blood, at rest
- they store blood and, through venous vasoconstriction, can move blood to other parts of the body if the need arises
36
What occurs during hemorrhaging?
- the result of varicosities in anal veins
- blood pressure and volume decrease
- vasoconstriction of veins in venous reservoirs help to compensate for the blood loss
37
Where are the principal reservoirs located?
veins of the abdominal organs (liver and spleen) and skin
38
What are the 3 ways substances enter and leave the capillaries?
- diffusion (most important)
- transcytosis
- bulk flow (filtration and absorption)
39
Capillary Diffusion
- important for solute exchange between plasma and interstitial fluid
- substances such as O2, CO2, glucose, amino acids, hormones, etc. diffuse down concentration gradients
- all plasma solutes, except larger proteins, pass freely across most capillary walls
- exception of diffusion of water-soluble materials against capillary walls is in the brain where blood-brain barrier exists
40
Transcytosis
the enclosing of substances within tiny vesicles that enter cells by endocytosis
41
Bulk Flow
- important for regulation of the relative volumes of blood and interstitial fluid
42
What 2 things are the movement of water and dissolved substances (except proteins) through capillaries dependent upon?
hydrostatic and osmotic pressures
43
Starling's law of the capillaries
most of the water that moved from the capillaries into the interstitial fluid at the arterial end will be returned to the bloodstream at the venous end
44
Edema
- an abnormal increase in interstitial fluid
- caused by the disruption of the balance of filtration and reabsorption between interstitial fluid and plasma
- may be caused by several factors including increased blood hydrostatic pressure in capillaries due to an increas in venous pressure
45
What factors can cause Edema?
increased blood hydrostatic pressure in capillaries due to:
- an increase in venous pressure
- decreased concentration of plasma proteins that lower blood colloid osmotic pressure
- increased permeability of capillaries which allows greater amounts of plasma proteins to leave the blood and enter tissue fluid
- increased extracellular fluid volume as a result of fluid retention
- blockage of lymphatic vessels postoperatively or due to filarial worm infection
46
What does the distribution of cardiac output to various tissues depend on ?
difference of the blood flow and resistance to blood flow
47
Blood Pressure
- the pressure exerted on the wall of an artery when the left ventricle undergoes systole and then diastole
- In clinical use, BP refers to pressure in arteries
48
What device is used to measure BP?
sphygmomanometer
49
What equation determines Cardiac Output (CO)?
mean aortic blood pressure (MABP) / total resistance (R)
50
What factors affect blood pressure?
- cardiac output
- blood volume
- viscosity
- resistance
- elasticity of arteries
51
Resistance
the opposition of blood flow as a result of friction between blood and the walls of the blood vessels
52
What are the 3 sources of blood flow resistance?
- blood viscosity
- total blood vessel length
- blood vessel diameter
53
Blood Viscosity
- the thickness or "stickiness" of blood due to formed elements and plasma proteins
- greater viscosity results in molecules less easily able to slide past each other (greater blood flow resistance)
54
Systemic Vascular Resistance
| AKA Total Peripheral Resistance
- all of the vascular resistances offered by systemic blood vessels
- most resistance is in arterioles, capillaries, and venules due to their small diameters
55
What is the only vessel that provides direct access to nearly every cell in the body?
capillaries
56
The presence of ______ stabilizes the wall of capillaries
pericytes: the outer surface of capillaries
57
Pericytes
contractile stem cells that can generate new vessels or scar tissue, stabilize the capillary wall, and help control capillary permeability
58
What is the rate of pressure as blood leaves the aorta and flows through systemic circulation to reach the right atrium?
0 mm Hg
59
Up to 65% of the body's blood supply is found in ______.
veins
60
What causes Venous Return?
venous return occurs because of the pressure gradient between the venules and the right atrium
61
What are some of the factors that maintain blood return to the heart? (3)
- skeletal muscular contractions
- valves in veins (especially in the extremities)
- pressure changes associated with breathing
62
Blood Flow
- the volume of blood that flows through any tissue in a given period of time
- volume of blood flow is inversely related to the cross-sectional area of blood vessels; blood flows most slowly where cross-sectional area is greatest
- blood flow decreases from the aorta to arteries to capillaries and increases as it returns to the heart
63
Syncope
fainting; a sudden, temporary loss of consciousness followed by spontaneous recovery
64
What is the most common cause of Syncope?
cerebral ischemia
65
Which two factors determine Arterial Blood Pressure?
- elasticity of arteries close to heart
- volume of blood forced into them at any time
66
Pulsatile
blood pressure that rises and falls with each heartbeat
Ex: near the heart
67
Systolic Pressure
- pressure exerted in aorta during ventricular contraction
- normal = 120 mm Hg (males); 110 mm Hg (females)
68
Diastolic Pressure
- lowest level of aortic pressure, recorded during ventricular relaxation
- normal = 80 mm Hg (males); 70 mm Hg (females)
69
What is the name of the various sounds heard while taking blood pressure?
Korotkoff Sounds
70
Pulse Pressure
- difference between systolic and diastolic pressure
- normally about 40 mm Hg
- provides information about the condition of the arteries
71
Pulse
- the alternate expansion and elastic recoil of an artery wall with each heartbeat
- throbbing of arteries due to difference in pulse pressures, which can be felt under skin
- strongest in arteries closest to the heart
72
What are vital signs to take for clinical monitoring of circulatory efficiency?
- pulse
- blood pressure
- respiratory rate
- blood pressure
73
What is the most commonly used artery to feel the pulse?
radial artery
74
What are the body sites where pulse is most easily palpated?
- superficial temporal artery
- facial artery
- common carotid artery
- brachial artery
- radial artery
- femoral artery
- popliteal artery
- posterior tibial artery
- dorsalis pedis artery
75
What is a normal resting pulse (heart) rate between?
70 to 80 bpm
76
Tachycardia
a rapid resting pulse rate ( > 100 bpm)
77
Bradycardia
a slow resting pulse rate ( < 60 bpm)
78
Vasomotion
- intermittent flow or blood through capillaries
- Due to on/off opening and closing of precapillary sphincters
79
Cardiovascular Center (CV)
a group of neurons in the medulla that regulates heart rate, contractility, and blood vessel diameter
80
What does the CV receive input from?
higher brain regions and sensory receptors (baroreceptors and chemoreceptors)
81
What fibers does the output from the CV flow along?
sympathetic and parasympathetic fibers
82
How do sympathetic impulses along cardio-accelerator nerve impact heart rate and contractility?
increase heart rate and contractility
83
How do the parasympathetic impulses along vagus nerves impact heart rate?
decrease heart rate
84
Vasomotor Tone
a moderate state of tonic contraction or vasoconstriction caused by the sympathetic division continually sending impulses to smooth muscle in blood vessel walls via vasomotor nerves
85
Baroreceptors
important pressure-sensitive sensory neurons that monitor stretching of the walls of blood vessels and the atria
86
What is the function of the Cardiac Sinus Reflex?
| What is it initiated by?
- maintaining normal blood pressure in the brain
- initiated by baroreceptors in the wall of the carotid sinus
87
What is the function of the Aortic Reflex?
| What is it initiated by?
- general systemic blood pressure
- initiated by barorecetpors in the wall of the arch of the aorta or attached to the arch
88
What is the function of the baroreceptors if blood pressure falls?
- the baroreceptors reflexes accelerate heart rate,
- increase force of contraction, and
- promote vasoconstriction
89
What is the benefit of a Carotid Sinus Massage?
it can slow heart rate in paroxysmal superventricular tachycardia
90
Chemoreceptors
- receptors sensitive to chemicals
- monitor blood levels of oxygen, carbon dioxide, and hydrogen ion concentration
91
Where are chemoreceptors located?
close to the baroreceptors of the carotid sinus and arch of the aorta
92
Which hormones affect blood pressure and blood flow?
| And How?
- angiotensin II, epinephrine, norepinephrine, antidiuretic hormone, atrial natriuretic peptide
- by altering cardiac output, changing systemic vascular resistance, or adjusting the total blood volume
93
Autoregulation
the ability of a tissue to automatically adjust its own blood flow to match its metabolic demand for supply of O2, nutrients, and removal of wastes
94
What is the principal stimulus for autoregulation in most body tissues?
Oxygen (not direct)
95
What are the two general types of stimuli that cause autoregulatory changes in blood flow?
physical and chemical
96
Shock
an inadequate cardiac output that results in failure of the cardiovascular system to deliver adequate amounts of oxygen and nutrients to meet the metabolic needs of body cells
97
What can occur as a result of shock?
- cellular membranes dysfunction
- cellular metabolism is abnormal
- cellular death may eventually occur without proper treatment
98
Hypovolemic Shock
| Caused by?
increased blood volume
99
Cardiogenic Shock
| Caused by?
poor heart function
100
Vascular Shock
| Caused by?
inappropriate vasodilation
101
Obstructive Shock
| Caused by?
obstruction of blood flow
102
What are some of the homeostatic responses to shock? (4)
- activation of the renin-angiotensin-aldosterone system
- secretion of ADH
- activation of the sympathetic division of the ANS
- release of local vasodilators
103
What are some of the signs and symptoms of shock?
- clammy, cool, pale skin
- tachycardia
- weak, rapid pulse
- sweating
- hypotension (systemic pressure < 90 mm Hg)
- altered mental status
- decreased urinary output
- thirst
- acidosis
104
What are the three circulatory routes of blood vessels?
- systemic circulation (largest)
- pulmonary circulation
- fetal circulation
105
What is the route of systemic circulation?
take oxygenated blood from left ventricle through aorta to all parts of body, including some lung tissue, and returns deoxygenated blood to right atrium
106
Hepatic Portal Circulation
collects blood from the veins of the pancreas, spleen, stomach, intestines, and gallbladder and directs it into the hepatic portal vein of the liver before it returns to the heart
107
Pulmonary Circulation
takes deoxygenated blood from the right ventricle to the air sacs of lungs and returns oxygenated blood from the lungs to the left atrium
108
How do pulmonary circulation and systemic circulation differ? (4)
- blood in pulmonary circulation is not pumped so far as in the systemic circulation
- pulmonary arteries have a larger diameter, thinner walls, and less elastic tissue
- resistance in pulmonary circulation is low, so less pressure is needed to move blood through lungs
- normal pulmonary capillary hydrostatic pressure is lower than systemic capillary hydrostatic pressure, which tends to prevent pulmonary edema
109
Fetal Circulation
the exchange of materials between fetus and mother
110
Placenta
structure that supplies fetus with oxygen and nutrients and eliminates fetus's carbon dioxide and wastes through the maternal blood supply
111
How does blood pass from the fetus to the placenta?
Blood passes from the fetus to the placenta via two umbilical arteries and returns from the placenta via a single umbilical vein
112
What functions are established at birth? (6)
- pulmonary, digestive, and liver functions are established
- ductus arteriosus becomes ligamentum arteriosum
- formaen ovale becomes fossa ovalis
- ductus venosus becomes ligamentum venosum
- umbilical arteries become medial umbilical ligaments
- umbilical vein becomes ligamentum teres (round ligament)
113
What is the process of the development of blood cells and blood vessels? (3)
- begins at 15 - 16 days in the mesoderm of the yolk sac, chorion, and body stalk
- few days later vessels begin to form within embryo
- blood vessels and blood cells develop from hemangioblasts
114
How do newborn blood vessels develop?
- blood vessels develop from angioblasts which are derived from hemangioblasts
- angioblasts aggregate to form blood islands
- spaces appear and become the lumen of the vessel
115
How do newborn blood cells develop?
blood cells develop from pluripotent stem cells which are also derived from hemangioblasts
116
What general changes are associated with aging and the cardiovascular system? (6)
- loss of compliance (extensibility) of the aorta
- reduction in cardiac muscle fiber size
- progressive loss of cardiac muscular strength
- reduced cardiac output
- a decline in maximum heart rate
- increased systolic blood pressure
117
What diseases increase with age?
- coronary artery disease (arteries narrow or fill with plaque, limiting blood flow to the heart)
- congestive heart failure (heart can't pump blood well enough)
- arteriosclerosis (thickening and hardening of the walls of the arteries)
118
Hypertension
- persistently high blood pressure
- systolic pressure 140 > mmHg
- diastolic blood pressure 90 > mmHg
119
Primary Hypertension
- approx. 90 - 95% of all hypertension cases
- cannot be attributed to any particular organic cause
120
Secondary Hypertension
- approx. 5 - 10% cases
- has identifiable underlying causes such as:
- obstruction of renal blood flow or disorders that damage renal tissue
- hypersecretion of aldosterone
- hypersecretion of epinephrine and norepinephrine by pheochromocytoma
- tumor of the adrenal gland
121
Why can it take a while for some people to realize they have high blood pressure?
- High blood pressure can cause considerable damage to the blood vessels, heart, brain, and kidneys before it causes pain or other noticeable symptoms
122
What lifestyle changes can reduce elevated blood pressure?
- losing weight
- limiting alcohol intake
- exercising
- reducing sodium intake
- maintaining recommended dietary intake of potassium, calcium, and magnesium
- not smoking
- managing stress
123
What are some drugs that have been used to successfully treat hypertension?
- diuretics
- beta-blockers
- vasodilators
- calcium channel blockers
