A&P 2 Circulation Flashcards
(147 cards)
1
Q
What are the 3 wall layers of arteries and veins from external to internal?
A
Tunica Externa (adventitia) Tunica Media Tunica Interna (intima)
2
Q
The Tuncina Externa is composed of what?
A
Elastic and collagen fibers (connective tissue)
3
Q
The Tunica Media and Tunica Intima of Arteries contain what, that Veins do not?
A
External and Internal elastic lamina
4
Q
What is continuous with the endocardial lining of the heart?
A
Endothelium
5
Q
What are the 2 major types of arteries?
A
Elastic
Muscular
6
Q
The Tunica Interna consists of what layers?
A
Internal elastic lamina (arterial)
Basement membrane layer
Endothelial cell layer
7
Q
The Tunica Media consists of what layers?
A
External elastic lamina (arteries)
Smooth muscle layer
8
Q
What does the Tunica Externa consists of?
A
Collagen fibers
Vasa Vasorum
9
Q
What is a momentary storage of mechanical energy called?
A
Pressure Reservoir
10
Q
Elastic arteries are also called?
A
Conducting arteries
11
Q
What are the muscular arteries?
A
Brachial
Femoral
Axillary arteries
12
Q
What is another name for muscular arteries?
A
Distributing arteries
13
Q
The Tunica Externa Layer is thicker in what type of arteries?
A
Muscular arteries
14
Q
A union of branches of two or more arteries supplying blood to the same region of the body are called?
A
Anastomoses
15
Q
What is it called when anastomoses provide alternate routes for blood to reach an organ?
A
Collateral circulation
16
Q
What are arteries that do not anastomose?
A
End-arteries
17
Q
The Tunica Externa Layer of Arterioles consists of what?
A
Areolar Connective Tissue containing unmyelinated sympathetic nerves
18
Q
A high firing rate of sympathetic tone will cause what to an artery?
A
Vasoconstriction
19
Q
A low firing rate of sympathetic tone will cause what to an artery?
A
Vasodilation
20
Q
Vasoconstriction of arterioles causes what?
A
Increased Blood Pressure
21
Q
Vasodilation of arterioles causes what?
A
Decreased Blood Pressure
22
Q
Branches off an arteriole that do not have a tunica media?
A
Metarterioles
23
Q
What is the blood vessel that has the largest surface area?
A
Capillaries
24
Q
The flow of blood from metarteriole through capillaries and into postcapillary venules is called?
A
Microcirculation
25
Capillaries are absent where?
Cornea
Lens of Eye
Cartilage
26
A network of 10-100 capillaries that arise from a single metarteriole is called?
Capillary bed
27
Contraction and relaxation of pre-capillary sphincters is called what and happens how often?
Vasomotion
| 5-10 times per minute
28
What is a metarteriole that has constricted sphincters to all capillaries except one?
Thoroughfare channel
29
What are the types of capillaries?
Continuous
Fenestrated
Sinusoids
30
Most capillaries are what type?
Continuous
31
Where can you find continuous capillaries?
CNS
Lungs
Skin
Muscle Tissue
32
Where can you find Fenestrated Capillaries?
```
Kidneys
Villi of Small Intestine
Choroid Plexus of Brain
Ciliary Process of Eyes
Most Endocrine Glands
```
33
Where can you find Sinusoid Capillaries?
```
Spleen
Anterior Pituitary
Parathyroid
Bone Marrow
Adrenal Glands
```
34
Some parts of the body may pass blood from one capillary network to another capillary networks through what?
Portal system
35
What are small veins that receive blood flow directly from capillary beds?
Postcapillary venules
36
What is the last sire of metabolic exchange?
Postcapillary Venules
37
As postcapillary venules move away from capillaries they become what?
Muscular Venules
38
What can serve as reservoirs for large amounts of blood if needed?
Postcapillary and muscular venules
39
Blood exiting a laceration by a steady oozing flow means what was lacerated?
Vein
40
Blood exiting a laceration by spurting means what was lacerated?
Artery
41
What type of veins travel between skeletal muscles?
Deep veins
42
What type of veins lie within the subcutaneous layer of the skin?
Superficial veins
43
What is the Blood Distribution breakdown?
```
64% - veins and venules
13% - arteries and arterioles
9% - pulmonary blood vessels
7% - capillaries
7% - heart
```
44
Substances enter and leave capillaries by what three basic mechanisms?
Diffusion
Transcytosis
Bulk Flow
45
What is the most important method of exchange where the substances move down the concentration gradient?
Diffusion
46
Filtration is described as?
Fluid and solutes "from" CAPILLARIES into interstitial fluid
47
Reabsorption is described as?
Fluids and solutes "from" INTERSTITIAL FLUID into blood
48
What is the equation for Net Filtration Pressure?
NFP = (BHP+IFOP) - (BCOP + IFHP)
49
BHP stands for what and does what?
Blood Hydrostatic Pressure
"Pushes fluid from capillaries into interstitial space"
50
IFOP stands for what and does what?
Interstitial Fluid Osmotic Pressure
"Pulls fluid out of capillaries into interstitial fluid"
51
BCOP stands for what and does what?
Blood Colloid Osmotic Pressure
"Pulls fluid from interstitial space into capillaries"
52
IFHP stands for what and does what?
Interstitial Fluid Hydrostatic Pressure
"Pushes fluid out of interstitial space into capillaries"
53
How much of the fluid filtered out of capillaries is reabsorbed?
~85%
54
What will happen to blood flow if you increase the length of the tubule?
Flow will DECREASE
55
As the pressure gradient against the tubule increases, what will happen to the flow?
Increases
56
If the viscosity of a tubule is increased; what will happen to the flow/
Decreases
57
The smaller the lumen, the _______the resistance of blood flow?
Greater "slower flow"
58
When arterioles dilate, resistance ______, and then blood pressure_______.
Decreases, decreases
59
When arterioles constrict, resistance ______, and then blood pressure_______.
Increases, increases
60
Blood viscosity is what?
Ratio of red blood cells to plasma volume
61
The higher the viscosity, the ______the resistance?
Higher "slower flow"
62
What effect does dehydration have on viscosity and BP?
Increases viscosity and BP
63
As the cross sectional area increases, what happens to the velocity?
Decreases
64
What is the usual blood circulation time for a single drop of blood in a healthy adult?
1 minute
65
If pressure in the right atria or ventricle increases, venous return______?
Decreases
66
What are 2 mechanisms that help return blood to the right side of the heart?
Skeletal muscle pump
| Respiratory pump
67
When standing at rest, the distal and proximal venous valves are _______?
Both OPEN
68
When the leg muscles contract (tiptoes), the proximal and distal venous valves?
Proximal OPENS
| Distal CLOSES
69
After standing on your tiptoes, the proximal and distal venous valves?
Proximal CLOSES
| Distal OPENS
70
What does the chemoreceptors reflex do?
Monitors concentration of various CHEMICALS in blood and STRECH
71
Two chemoreceptors and what do they do?
Carotid bodies- receptors in carotid arteries
Aortic bodies- receptors in aortic arch
72
What activates the chemoreceptors reflex? Examples of this and what the response it?
Changes in blood concentration of O2, CO2, and H+
Hypoxia- Reduced O2
Acidosis- Increased H+
Hypercapnia- Increased CO2
- Response is VASOCONSTRICTION and INCREASED BP
73
What do baroreceptors do?
Monitor changes in PRESSURE and STRECH in VESSLE WALLS
74
What activates baroreceptors?
The stretching of the carotid sinus or aortic arch receptors.
75
What are the two baroreceptors and what do they regulate?
Carotid Sinus Reflex- Regulates BP in the BRAIN
Aortic Reflex- Regulates SYSTEMIC BP
76
In the carotid sinus reflex where do nerve impulses propagate?
From sinus baroreceptor over sensory axons in glossopharyngeal nerves then into cv
77
In the aortic reflex where do nerve impulses propagate?
From baroreceptors reach the cv center via sensory axons of vagus nerves
78
What happens when the baroreceptors are stretched less?
- Causes drop in BP
- Nerve impulses to be sent SLOWER rate to CV center
- CV center DECREASES parasympathetic stimulation through vagus nerves and INCREASES sympathetic stimulation through cardiac accelerator nerves
- This INCREASES the BP back to normal levels
79
What happens when the baroreceptors are stretched more?
- Causes increase in BP
- Nerve impulses are sent FASTER rate to CV center
- CV center INCREASES parasympathetic stimulations through the vagus nerves and DECREASES sympathetic stimulations through the cardiac accelerator nerves
- This DECREASES the BP back to normal rate
80
What is the pressure gradient throughout the body?
- BP progressively DROPS as the distance INCREASES from the left ventricle
81
What does the BP drop to by the time the blood reaches the capillary levels
35mmHG
82
What does the BP drop to when it reaches the venous ends of capillary levels?
16mmHG
83
What is the estimated BP when it reaches the right vertical?
0mmHG
84
Systolic BP and Diastolic BP in arteries
- Highest BP in arteries during systole
| - Lowest BP in arteries during diastole
85
BP is determined by
- Cardiac Output
- Blood Volume
- Vascular Resistance
86
What happens at the capillary level during vasomotion?
- Contraction and relaxation of pre-capillary sphincter
- Ensures capillary bed receives blood flow during rest
- Happens 5-10 times a minute
87
Alternate name for elastic arteries
Conducting arteries
| -Conduct blood from heart to medium sized muscular arteries
88
Alternate name for muscular arteries
Distributing arteries
| -Continue to branch and distribute blood to each of the organs
89
Alternate name for arterioles
Resistance vessels
| -Resistance is due to blood rubbing against vessel wall
90
Alternate name for capillaries
Exchange vessels
| - exchange substances between blood and interstitial fluid
91
What happens during inhalation of the respiratory pump?
Diaphragm move downward causing DECREASE in pressure in thoracic cavity, INCREASE in abdominal cavity pressure
92
What happens to the abdominal veins during inhalation of the respiratory pump?
Abdominal veins are compressed pushing GREATER volume of blood through thoracic cavity towards the heart
93
What happens during exhalation of the respiratory pump?
Diaphragm move upward causing INCREASE in thoracic cavity pressure, but DECREASE in abdominal cavity pressure
94
What happens to the valves during exhalation of the respiratory pump?
Valves CLOSE preventing black flow from thoracic veins into abdomen
95
What is the cross sectional area concept?
Area INCREASES, velocity DECREASES
96
Which part of the body has the largest cross sectional area and what is its velocity?
Capillaries
| - Slowest velocity
97
Which part of the body has the smallest cross sectional area and what is its velocity?
Aorta
| -Fastest velocity
98
What cells release chemicals that indirectly alter blood vessels?
WBC's, Platelets, Smooth muscle fibers, Macrophages, Endothelial cells
99
Which are the vasodilating chemicals?
K+, H+, lactic acid, adenosine, nitric oxide (NO), kinins, histamine
100
What are the vasoconstricting chemicals?
Thromboxane A2, Surperoxide radicals, Serotonin, Endothelins
101
In Poiseuille's Law CO becomes distributed into circulatory route by two factors?
Flow
| Resistance
102
How is flow affected?
- Pressure gradient from one end of the tube to the other
- Radius of the tube to the fourth power
- Viscosity of the fluid
- Length of tube
103
How is resistance affected?
- Radius of the tube to the fourth power
- Viscosity of fluid
- Length of the tube
104
The longitudinal pressure gradient is proportional how?
Directly
105
The radius of the tube to the fourth power is proportional how?
Directly
106
The viscosity of the fluid is proportional how?
Inversely
107
The length of the tube is proportional how?
Inversely
108
Volume of fluid and salutes reabsorbed is near the volume of the fluid filtered
Starling's Law
109
What are significant sites of exchange of nutrients and wastes and is the last site for?
Post capillary venules
| - metabolic exchange
110
Where does the blood brain barrier lack?
Hypothalamus, pineal gland, and pituitary gland
111
What does the blood brain barrier allow?
Capillary exchange to occurs more freely
112
What is the tone of the sympathetic?
Sympathetic
- High rate of firing: vasoconstriction
- Low rate of firing: vasodilation
113
What do epi / norepinephrine do?
- Both INCREASE CO by INCREASING rate and force of contraction
- Cause vasoconstriction of arterioles and veins in the SKIN and ABDOMINAL GLANDS
- Cause vasodilatation of arterioles and veins in CADIAC and SKELETAL
114
What makes up the cardiovascular center, where is it located, what does it help regulate?
- Located in the medulla oblongata
- Helps regulate HR and SV
- Controls neural, Humoral, and local feedback systems that help regulate BP
115
The vasomotor center is made up of and what does it do?
Vasoconstrictor center- neurons that cause contraction of vessels
Vasodilator center- neurons that cause dilation of vessels
116
What is the mean arterial pressure, calculation, definition, and normal vs abnormal?
Is the average BP in arteries
- roughly 1/3 of the way between diastolic and systolic pressures
- pressure needed to perfuse vital organs
MAP = Diastolic BP + 1/3 (systolic BP- diastolic BP)
Normal MAP: 70-100
117
What happens during tanscytosis?
- Small quantity of material crosses capillary walls
- substances in blood plasma become enclosed in tiny Pinocchio vesicles
(Endocytosis followed by exocytosis)
- Used mainly for large, lipid-insoluble molecules
118
What sets the resting level of vascular resistance?
Vasomotor / vascular tone
119
Where does diffusion occur?
- Intercellular clefts/ fenestrations
- Endothelial cell lipid bilayer
- ????
- Brain capillaries
120
How does diffusion occur in intercellular clefts/ fenestrations?
Through water soluble substances
| -Glucose and amino acids
121
How does diffusion occur in endothelial cell lipid bilayer?
Lipid soluble substances
| - O2, CO2, steroid hormones
122
How does diffusion occur in the brain capillaries?
Only allow few substances to diffuse
- Water, some gases, lipid soluble molecules
- Others like glucose and amino acids are selectivity transported (carrier mediated)
Most areas of brain have continuous capillaries
- Very "tight" junctions
- Endothelial cells very closely packed together
- Blocks many substances from passing though this blood-brain barrier
Certain parts of brain lack blood-brain barrier and allow capillary exchange to occur more freely
-Hypothalamus, penal gland, pituitary gland
123
During diffusion O2 does what?
Diffuse down their concentration gradient into interstitial fluid
-because they have high concentration in blood then tissue/interstitial fluid
124
During diffusion CO2 does what?
Diffuses down their concentration gradient into blood
| -because cells are higher in concentration in interstitial fluid
125
Most RBC's and plasma proteins cannot pass through continuous or fenestrated capillary walls as they are too big so they have to pass though where?
Sinusoids
- Liver (proteins)
- Bone marrow (RBCs)
126
Passive process by which large numbers of ions, molecules, or particles in a fluid move together in same direction?
Bulk Flow
127
What rate of movement is much greater than diffusion?
Bulk Flow
- Movement from high pressure to low pressure
- Continues as long as a pressure difference exists
128
What is diffusion more important for?
Solute exchange
129
What is bulk flow more important for?
Regulation of relative volumes of blood and interstitial fluid
130
Pressure blood exerts against blood vessel walls
BHP
131
Force caused by colloidal suspension of proteins in plasma
BCOP
132
Normally small pressure, only small amounts of protein present in interstitial fluid
IFOP
133
Opposing pressure to BHP
IFHP
134
Input to CV center
Higher brain regions cerebral cortex, lambic system, hypothalamus
135
Output from CV center
Flows along sympathetic and parasympathetic neurons of ANS
Sympathetic impulses reach heart via cardiac accelerator nerves (thoracic vertebrae)
-Increase HR and contractility
Parasympathetic impulses conveyed along vagus nerves
-Decrease HR
136
What happens to the excess filtered fluid and plasma proteins that escape from blood into interstitial fluid and what percent? (Not reabsorbed)
Enter lymphatic capillaries (~15%)
137
What is unique about the sinusoids?
- Wider then others
- Incomplete or absent basement membranes
- Unusual large fenestrations
- Large intercellular clefts
- Specialized lining
138
What portal system pass from one capillary network into another capillary network in the liver?
Hepatic portal circulation
139
What portal system pass from one capillary network into another capillary network in the pituitary?
Hypophyseal portal system
140
Major elastic arteries?
```
Aorta
Braciosephalic
Common carotids
Common iliacs
Pulmonary trunk
Subclavian
```
141
What does the tunica externa in the muscular arteries?
Thicker then elastic arteries
- Fibroblasts
- Nerve fibers
- Some collagen
- Elastin
142
What does the tunica media in the muscular arteries?
- Contains much more smooth muscle but less elastic fibers
| - Adjusts rate of blood flow
143
What does the tunica intima in the muscular arteries?
Endothelial cells
144
What does the tunica externa in the elastic arteries?
Fibroblasts, nerve fibers, and vasa vasorum (blood vessel network)
145
What does the tunica media in the elastic arteries?
- More elastic fibers called elastic lamellar than other vessels
- More collagen fibers
- Minimal smooth muscle
146
What does the tunica intima in the elastic arteries?
Endothelial and myointimal cells with supporting layer of elastin rich collagen
147
Subdivisions of systemic circulation
Coronary
Cerebral
Hepatic Portal
