Unit 3/4: CVS Vessels & Circulation Flashcards
1
Q
What are the largest type of arteries?
A
Elastic arteries (2.4 to 1 cm) diametre)
2
Q
What allows for stretch and recoil in elastic arteries?
A
The many elastic fibres in the tunics
3
Q
What are the medium sized category of arteries?
A
Muscular (1cm to 0.3mm)
4
Q
The brachial and coronary arteries are examples of ________ arteries.
A
Muscular
5
Q
What are the smallest type of arteries?
A
arterioles (0.3mm to 10 micrometres)
6
Q
What is missing from smaller arterioles as compared to other arterial structures?
A
Tunica externa (only have thin endothelium and single smooth muscle layer)
7
Q
Which arteries are the “conducting arteries”?
A
Elastic (elastic fibres allow for constriction and dilation to pump blood throughout body)
8
Q
What arterial structure are responsible for regulating systemic blood pressure and flow?
A
arterioles
9
Q
T or F: Veins have thinner tunica externa as compared to arteries.
A
False- veins have thicker tunica externa
10
Q
What part of the brain regulates vasomotor tone?
A
medulla oblongata
11
Q
What is vasomotor tone?
A
The degree to which blood vessels contract and relax - a key factor in regulating blood pressure and tissue perfusion.
12
Q
T or F: Veins have more elastic and collagen fibres as compared to arteries.
A
False- veins has less elastic and collagen fibres as compared to arteries.
13
Q
What is the purpose of valves?
A
Prevent backflow and keep blood from pooling in limbs to ensure flow to heart.
14
Q
T or F: Venules have no valves but still have all 3 tunics.
A
True
15
Q
Diametre of venules.
A
8-100 micrometres
16
Q
List the tunic(s) of capillaries.
A
Tunica intima- no subendothelial layer.
17
Q
How large are capillaries?
A
1 mm in length, 8-10 micrometers in diameter
18
Q
What are the 3 types of capillaries?
A
Continuous, Fenestrated, Sinusoid.
19
Q
Which tunica is thickest in arteries
A
tunica media
20
Q
Which tunica is lined by endothelium (simple squamous epithelium)?
A
tunica intima
21
Q
Which tunica is a sheath of connective tissue with collagenous fibres?
A
externa
22
Q
Which tunica is thickest in veins?
A
Externa
23
Q
T or F: Capillaries are much larger than erythrocytes.
A
F: Only slightly larger than a single erythrocyte (which means erythrocytes have to travel almost single file through them)
24
Q
What type of capillaries are found in areas of high fluid transport? (kidney, intestines)
A
Fenestrated
25
Average Pressure of arteries:
High: 40-100 mmHg
26
Average pressure of veins:
Low: 0-20 mmHg
27
What is the least common type of capillary?
Sinusoid (large opening on endothelial lining allow for passage of large molecules; plasma, proteins )
28
What separates continuous capillaries from fenestrated and sinusoid?
Complete endothelial lining
29
Where would you find an arteriovenous anastomosis?
fingers, toes, palms, ears
30
How does bulk flow use filtration and reabsorption for mass movement of fluids in and out of capillary beds?
filtration- increase P in capillary to decrease P in tissue
reabsorption- increcrease P in tissue to decrease P in capillary
31
What are the two types of pressure that drive filtration and reabsorption?
Hydrostatic (HP) and Colloid osmotic (COP)
32
How does Hydrostatic Pressure work?
Forces fluid out of capillary.
Blood HP (HPb)- force exerted by blood inside the vessel
Interstitial fluid HP (HPif)- force exerted by te interstitial fluid outside of vessel
33
Describe bulk flow.
- Fluids flow down a pressure gradient (high to low)
- Large amounts of fluids (and dissolved substances) move between capillaries and interstitial fluid of tissues (they only move 1 direction because they only move from high to low concentration)
- Critical for fluid balance between blood and interstitial space
34
Describe the qualities of filtration and reabsorption in regards to bulk flow.
Filtration
- Movement of bulk flow out of the blood
- Arterial end
- Related to the pressure inside and outside vessel and same with reabsorption
Reabsorption
- Movement of bulk flow back into the blood
- At venous end
35
What is colloid osmotic pressure (COP) and how does it work?
Pressure tha large molecules in fluid exert to keep water in the blood vessels.
- based on solute concentration and osmosis
- forces fluid back into capillary
36
What is net filtration pressure?
Interaction between hydrostatic and colloid osmotic pressure.
37
What occurs if the NFP is positive?
Filtration.
Negative NFT = reabsorption
38
Calculate the NFP if the blood hydrostatic pressure (HPb) is 35 mmHg and the blood colloid pressure (COPb) is 25 mmHg.
+10 mmHg filtration
NFP= (HPb-HPif) - (COPb - COPif)
=(35-0) - (25-0)
= +10mmHg
39
List the 4 factors that control local blood flow.
1. Degree of vascularity
2. Myogenic Response (constant blood flow to a tissue, controlled vasoconstriction and vasodilation)
3. Local Regulatory Factors (vasoactive chemicals- inflammation)
4. Total Blood Flow (cardiac output)
40
What type of pressure is blood pressure a form of?
Hydrostatic pressure
41
How do you calculate pulse pressure?
pulse pressure = (systolic pressure) - (diastolic pressure)
42
How do you calculate mean arterial pressure?
MAP = diastolic BP + (pulse pressure/3)
43
T or F: pressure in veins must be greater than pressure in atrium of heart.
True
44
List two factors that affect venous return.
1. Pressure is very low ub atrium during diastolic (~ 0mmHg)
2. Pumps (increase venous pressure)
45
List and describe the types of pumps in the venous system.
1. Skeletal Muscle Pumps (assist in venous return from limbs, P in veins can be increased by contracting surrounding muscles)
2. Respiratory Pump (assist in venous return from thorax, exhalation moves blood into atrium)
46
List 3 factors that influence resistance.
1. Blood Viscosity (thickness of fluid, inc. Viscosity = incr Resistance = decr. Flow)
2. Vessel Length (incr. Length = incr Resistance = decr. Flow)
3. Vessel Diametre (incr/ Diametre = decr. Resistance = incr. Flow)
47
Explain how to find total blood flow.
Total blood flow is proportional to the blood pressure gradient divided by total peripheral resistance. (F= delta P/R)
48
What are the average capillary blood pressures at the arterial and venous end?
Arterial ~ 35-40 mmHg
Venous ~ 20 mmHg
49
Which vessel layer is involved in blood clotting and immune response?
Tunica intima
50
What type of tissue is the tunica intima?
endothelium: simple squamous epithelium
subendothelial layer: loose connective tissue (in larger vessels)
51
Which layer anchors the vessel and provides structural support and protection?
tunica externa
52
What type of tissue is the tunica media made of'?
circularly arranged smooth muscle cells with elastic fibres
53
What type of tissue is tunica externa made of?
Areolar connective tissue with elastic and collagen fibres
54
Where are valves formed?
Primarily of tunica intima and strengthened by elastic and collagen fibers - valves have an anatomic structure similar to semilunar valves of the heart
55
Identify the structures of a capillary bed and describe how these structures and blood flow regulate capillary exchange.
1. Arteriole- smallest artery that leads to capillary bed
2. Metarteriole- branch of of an arteriole which feeds the capillary bed; serves as vascular shunt when precapillary sphincters are closed; origin of capillary bed
3.Precapillary Sphincter - control blood flow in and out of the capillary bed; usually closed unless tissue needs it; smooth muscle; origin of true capillary
4. True Capillary- branch from the metarteriole and make up the bulk of the capillary bed
5. Thoroughfare channel- distal part of the metarteriole that connects to a post capillary venule which drains the capillary bed
6. Venule- companion vessels to arterioles; smallest veins
56
What types of solutes cross the 3 types of capillary walls?
Sinusoid - Large substances (formed elements, large plasma protein) and plasma
Fenestrated - large amounts of materials are filtered, released, or absorbed; some smaller proteins
Continuous - Plasma and its contents (except most proteins); some leukocytes
57
Know how baroreceptors regulate blood pressure by altering both heart and blood vessels when homeostasis is disrupted.
Baroreceptors are specialized sensory nerve endings that respond to stretch. Detecting stretch of the blood vessel wall that occurs as the blood volume within them changes. The two main baroreceptors for the cardiovascular system are those located within the aortic arch and carotid sinuses, specifically within the tunica externa
Baroreceptors connect to our cranial nerves (vagus, glossopharyngeal) and allow us to send sensory neurons about the stretch in these specific areas. This is important for systemic blood pressure
Vagus is for head and neck which is very important
58
What part of the brain is the cardiovascular centre located?
medulla oblongata
59
What are the two centres within the cardiac centre and what do they control?
Cardioinhibitory Centre
- parasympathetic
- decreases HR
Cardioacceleratory Centre
- sympathetic
- Increases HR and SV
60
What does the vasomotor centre do?
Controls contraction of smooth muscle of vessels (changes diameters of vessels)
61
What controls short term blood pressure regulation?
baroreceptors and chemoreceptors
62
Trace the path of blood flow of the pulmonary circuit.
RV - pulmonary trunk - pulmonary arteries - arterioles - pulmonary capillaries - venules - pulmonary veins - LA
63
What are the 3 major branches of the aortic arch?
1. Brachiocephalic Trunk
2. Left common carotid artery (divides into internal and external carotid)
3. Left Subclavian artery (supplies to arms, chest, shoulder, back and CNS)
64
What are the 3 branches of the Celiac Trunk?
1. Left Gastric Artery
2. Splenic Artery
3. Common Hepatic Artery
65
Trace the pathway of the upper limbs arteries.
Aorta - brachiocephalic trunk - subclavian - axillary - brachial (deep brachial) - radial - ulnar - palmer arch - digital
66
List the branches of the subclavian artery.
1. Vertebral
2. Thyrocervical
3. Internal Thoracic
67
Trace the pathway of the lower limb arteries.
Descending abdominal aorta - common iliac - external iliac - femoral (deep femoral) - popliteal - anterior and posterior tibial (fibular) - plantar arches - digital
68
What part of the heart do veins return blood to?
RA
69
What are the two main veins that drain into the SVC?
1. Brachiocephalic (subclavian fuses with external and internal jugular veins)
2. Azygos (drains thorax, esophageal, bronchial, hemiazygos)
70
What are the 3 veins that drain into the potal venous system?
1. Inferior mesenteric (large intestine)
2. Superior mesenteric (small/large intestine and stomach)
3. Splenic (spleen, pancreas, stomach)
71
What are autonomic reflexes?
Responds to changes in blood pressure as well as blood concentrations of oxygen, carbon dioxide and hydrogen ions. (nuclei within medulla oblongata)
72
Explain the function of Aldosterone.
Helps maintain blood volume and pressure
Released from adrenal cortex
Increases reabsorption of sodium ions and water in kidneys
Decreases urine output
73
Explain the function of Antidiuretic hormone (ADH).
-Helps maintain or elevate BP
-Released by posterior pituitary gland
-Increases water reabsorption in kidney, stimulates thirst center and causes vasoconstriction
74
Explain how blood flow changes during exercise.
-Total blood flow increases during exercise
-Heart beats faster and stronger
-Blood removed from reservoir with increased BP
-Blood redistributed to active tissues
75
Concerning the exchange between blood and interstitial fluid at systemic capillaries, more fluid is _____ than ______.
filtered, reabsorbed.
76
T or F: Atherosclerosis involves a sustained increase in resistance that leads to increases in arterial pressure to maintain adequate blood flow.
True
77
T or F: Blood flow is indirectly related to the pressure gradient but directly related to the resistance.
False. Blood flow is directly related to the pressure gradient but inversely related to the resistance.
78
A venule becomes a vein when its diameter is greater than _________ micrometers.
100
79
Low blood pressure may cause the net hydrostatic pressure of a capillary to be less than normal. This will result in a(n) _________ net filtration pressure.
decreased
80
At a capillary bed, a ________ stimulates precapillary sphincters and decreases local blood flow.
Vasoconstrictor
81
Which is the most common type of capillary?
Continuous
82
A network of small arteries called the _________ provides a blood supply to the tunica externa of very large vessels.
Vasa Vasorum
83
Which of the artery types contain the internal and external elastic laminae?
Muscular
84
In general, as an artery’s diameter decreases, the artery walls show
an increase in the relative amount of smooth muscle and a decrease in the relative amount of elastic fibers
85
T or F: Filtration involves bulk flow of fluid out of the blood, whereas reabsorption is bulk flow back into the blood.
True
86
T or F: A portal system is one in which blood flows through two capillary beds before being sent back to the heart.
True
87
Which part of the circulatory system holds the largest amount of blood?
Systemic veins
88
T or F: Systolic blood pressure is recorded in arteries and is the maximal pressure that is recorded during atrial contraction
False. Systolic blood pressure is recorded in arteries and is the maximal pressure that is recorded during ventricular contraction.
89
T or F: Peripheral resistance is directly related to vessel length and inversely related to vessel radius.
True
90
Increased cardiac output decreases, increases or does not affect blood pressure?
Increases
91
The superior vena cava is formed by the merging of the _________veins.
Brachiocephalic
92
The artery that arises from the descending aorta and is immediately inferior to the celiac trunk is the _________ artery.
Superior mesenteric
93
Superior phrenic arteries supply the _________ and emerge from the _________.
diaphragm; descending thoracic aorta
94
The arteries that anastomose and form the two arterial arches in the palm are the _________and _________ arteries.
radial; ulnar
95
The artery that bifurcates into the right subclavian artery and the right common carotid artery is the:
brachiocephalic artery.
96
Aldosterone and atrial natriuretic peptide have opposite or similar effects on blood pressure?
Opposite
97
Where is Angiotensin II mainly formed?
Lungs
98
Where is aldosterone produced?
adrenal cortex
99
Where is ADH released from?
posterior pituitary
100
Where is ANP secreted?
Atrium
101
Where does the pulmonary circulation pathway begin?
RA
