Cardiovascular System Flashcards
1
Q
Define cardiovascular system
A
Transport of materials to different parts of the body
2
Q
What does the heart, blood vessels and blood do
A
Generates movement, form a pathway, and is a medium
3
Q
What is hematocrit?
A
% of red blood cells that are blood
4
Q
What is pulmonary responsible for?
A
Lungs and gas exchange (bottom)
5
Q
What is systemic responsible for?
A
Pickup and delivery for all tissues
6
Q
What is blood flow drive by?
A
Pressure created by ventricular contraction by the resistance offered by a narrow blood vessel
7
Q
What WAY does blood flow?
A
Down a pressure gradient, from high to low
8
Q
What is blood viscosity?
A
Thickness/stickiness of blood, resistance increases with this
9
Q
What does vessel length have to do with resistance?
A
Resistance increases with length
10
Q
What does vessel radius have to do with resistance?
A
Resistance increases as the radius decreases
11
Q
What is the formula for R?
A
R = 8Ln/PIEr^4
12
Q
What does a 2-fold change in vessel radius result in?
A
a 16 fold change in resistance
13
Q
What is flow rate?
A
Volume of blood that passes point in given time (L/min)
14
Q
Define velocity of flow
A
Distance travelled in given time (cm/min)
15
Q
What is the formula for V?
A
V = Flow rate/Cross sectional area
16
Q
What is the formula for pressure gradient?
A
P = P1-P2
17
Q
What has the highest and lowest pressure?
A
Aorta and Vena Cavae
18
Q
What is the base and apex of the heart?
A
Base = wide part, Apex = point
19
Q
Where does blood pass through?
A
Passes through valves to get in and out of ventricles
20
Q
Where are the AV valves?
A
Between the atria and ventricles
21
Q
Where are the SL valves?
A
Between the ventricles and pulmonary trunk (or aorta)
22
Q
What is the pulmonary system compared to the systemic?
A
Pulmonary is low resistance, low pressure system compared to systemic
23
Q
What are the action potentials in pacemaker cells?
A
Minimum is 60 which is due to net inward leak of Na+, depolarizes cell to threshold, action potential is initiated
24
Q
Define contractile cells
A
Able to get smaller, sympathetic stimulation increases contractility
25
Define skeletal muscle fiber
Refractory period very short compared to length of twitch
26
Define short refractory period
Permits tetanus of contraction
27
What is excitation contraction coupling and how does it work?
- AP in nehibouring cells send positive ions through gap
- Cell membrane depolarizes to threshold, AP initiated
- AP spreads along cell membrane and into T tubules
- When voltage gated Ca channels open, Ca enters cell and induces release of Ca from SR via CA release channels
- Ca initiate cross bridge cycle
- Cell contracts
28
What is relaxation and what happens?
- Membrane repolarizes, Ca release channels close
- Ca dissociates from troponin, some Ca pumped back into SR
- Some Ca leaves cell via Na/Ca exchanger
- Some Ca pumped out of cell
- Na/K pump maintains membrane potential
29
What are the effects of sympathetic nerve stimulation?
depolarized membrane potential
Increased slope of pacemaker potential
INCREASED HEART RATE
30
What are the effects of parasympathetic stimulation?
hyper polarized minimum potential
decreased slope of pacemaker potential
DECREASED HEART RATE
31
What is the sympathetic control of contractility?
If more Ca enters the cell, then more Ca is released from the SR
More Ca ions bind to troposin, so more cross bridges are formed
Therefore stronger contraction
32
Pacemaker cells in the SA node?
Produce spontaneous AP in a rhythmic fashion, results in the propagation of AP throughout the heart
33
What are P, QRS and T waves?
```
P = atrial depolarization
QRS = ventricular depolarization
T = Ventricular repolarization
```
34
Why is an ECG useful?
It has particular features that serve to mark the timing and quality of particular cardiac electrical events
35
Cardiac cycle of contraction?
Ventricular filling - Isovolumetric contraction - Ventricular ejection (systole, 0.3 sec)
36
Cardiac cycle of relaxation?
Isovolumetric relaxation - Ventricular filling (diastole, 0.5 sec)
37
What happens during systole?
Contracting of the heart, AV valves shut, SL valves open
38
What happens during diastole?
Relaxation of the heart, AV valves open, SL valves shut
39
What is cardiac output and what is the formula?
It is the volume of blood pumped out by EACH ventricle in one minute (typical value 5L/min)
Formula is CO = HRxSR
40
What is stroke volume and what is the formula for it?
Volume of blood pumped out of the ventricle during one contraction
Formula is SV = CO/HR or EDV - ESV
It is determined by preload, sympathetic input to ventricles and after load
41
What is Starlings law of the heart?
More blood in results in more blood out, the more blood in the ventricles the more the muscle fibres are stretched
42
What kind of tissue is an Artery, Arteriole, Capillary, Venule and Vein?
Elastic, Smooth, Endothelial, Endothelial, Elastic and smooth
43
What is systolic pressure and diastolic pressure?
```
Sys = highest pressure during ventricle ejection
Dias = Lowest pressure during ventricular relaxation
```
44
What is pulse pressure?
Systolic - Diastolic
| 120-80 = 40 mmHg
45
What is mean pressure? What is the formula?
MAP relatively constant in large arteries, blood enters from heart and leaves through arterioles
Formula is DP + 1/3 (SP-DP) = 93 mmHg
46
What happens with the branching of arterioles into narrow arterioles?
Results in high resistance to blood flow through the narrow arteriolar vessels
47
Define vasoconstriction and vasodilation
```
vasocon = increased resistance, angiotestin II
vasodil = decreased resistance, ANP
F = P/R
```
48
What are arterioles?
Vessels where the greatest drop in mean blood pressure occur
49
What are the 3 capillary types?
```
Continous = closely joined, muscles, nervous
Fenestrated = Large pores, kidneys, intestines
Sinusoids = Wide fenestrated bone marrow, liver, spleen
```
50
Define diffusion, transcytosis and Bulk flow
Diffusion = exchange of nutrients, oxygen and metabolic end points
Transyctosis = Move larger solutes and proteins
Bulk Flow = movement of fluid between capillaries and ISF
51
Define hydrostatic pressure and Calloid osmotic pressure
```
Hydrostatic = pushes
Calloid = Pulls
```
52
Define filtration and absorption
Filtration is out of capillaries into ISF
| Absorption is into capillary from ISF
53
Define net pressure
Hydrostatic - Colloid
Fluid moves out of arterial end, most returned at venous end
Pc decreases from a retrial to venous ends of capillaries due to FRICTION
54
What route is travelled by blood from the venous end of capillaries back to the heart?
Smooth muscle
Due to the presence of smooth muscle the diameter of the veins can be altered by sympathetic discharge of hormones like adrenaline and angiotensin II
55
Why is the lympethic system needed? What is its function?
for fluid transport, consists of valves, smooth muscle and skeletal muscle pumps.
Function is to return fluid filtered out by capillaries and returned to veins near the right atrium, app 3L
56
What is edema?
Accumulation of ISF which leads to failure of sympathetic system
57
Define lymph
Fluid, protein and bacteria
58
Arterial blood pressure by baroreceptor reflexes are what 4 things?
```
Monitor = barorecpetors
Integration = medullary cardiovascular system
Effector = Heart, arterioles, veins
Adaptation = setpoint reset
```
59
What is the renal system responsible for?
Control of blood pressure, the kidneys can change volume by how much it excretes
60
What is hypotension and orthostatic hypotension?
Hypotension = Low blood pressure
| Orthostatic pressure = lying down to standing up, gravity causes pooling
61
What are the reasons for loss of blood volume? What happens when there is a haemorrhage?
Haemorrhage, sweating, dirrehea
When their is a haemorrhage the baroreceptor reflex kicks i and try to compensate to bring the MAP towards normal, BR increases the heart rate therefore bringing back up the blood pressure
62
What are the major effects of exercise on blood flow? Where does the remaining blood go?
Normal distribution of blood during exercise goes to feeding your skeletal muscles, goes from resting 1.22 L/min to 22.5 L/min, large portions of remaining blood goes to heart
63
What is shock and what are the 4 causes?
An extreme drop in blood flow
1. Cardiogenic - heart fails to pump enough blood to maintain normal CO
2. Hypovolumic - decreased blood flow in circulation
3. septic - bacterial toxins
4. anaphalyatic - immune reaction, widespread vasodilation
64
What is coronary heart disease and heart attack and what are the risk factors?
They are atheroscleoresis which means that arteries form plaques which cause decreased blood flow
Risk are hypertension, smoking, obesity, inherited factors, etc.
65
What is hypertension and what is the problem with it?
A chronically increased systemic arterial pressure, usually due to vasoconstriction and therefore increase TPR
Problem is the heart has to work harder to pump out blood, endothelial cells lining vessels may be damaged, blood vessels report and adaptation of baroreceptor reflex
66
What are the 3 major types of blood cells?
Red blood cells - erythyocytes, transport Co and O
White blood cells - leukocytes, immune/defence
Platelets - cell fragments, thrombocytes, hemostatsis
67
What is plasma?
more than 90% (93%) water. it also includes ions, organic molecules, trace elements, vitamins and gases
68
What is the normal hero crit?
Males = 45-52
Females = 37-48
Blood volume, 5L females normally less
69
Define erthyroposis
Red blood cell production
70
What is a cytosine regulator?
Erythopoitin, which is a substance released by the kidneys in response to low O2 levels
71
What is the life span of a RBC?
4 months
72
Define hemoglobin
4 global chains with a heme group. Oxygen binds to each iron, max 4 per hb molecule. hemoglobin carry the O2 in the blood
73
What does Iron do?
Makes more RBC or stored in liver as peroration or travels in blood bound transferrin
74
What are the 3 steps in the Iron cycle?
1. Spleen = hemoglobin is broken in global (amino acids) and heme
2. Iron - make more RBC or stored in liver as ferratin
3. Birirubin = broken down in liver, excreted in feces or urine
75
Define anemia
Decreased ability to carry oxygen
76
Define hemostasis
Keep blood within damages vessel
77
How do you seal a cut or torn blood vessel? 5 steps
1. damage occurs
2. paracrine released by endothelium
3. vasoconstriction vascular spasm
4. temporarily decreases flow and pressure in affected vessel
5. Temporary hemostasis
78
Talk about platelet plug formation and what it is
Mechanical blocking of a hole
Fragments pinched off by megakaryotic
No nucleus, colorless
Life expectancy 10 days
79
What are activated platelets and what do they look like
Spiky outer surface and are able to stick to each other (AAA)
80
Define TXA2
Thromboxane A2, vasoconstrictor, platelet aggressor
81
Define Heparin
Compound occurring in the liver that inhibits blood coagulation, it is used as an anticoagulant in the treatment of thrombosis
82
Define tPA
Tissue plasminogen activator, involved in the breakdown of blood clots
83
Define fibrin
An insoluble protein formed from fibrin during blood clotting, forms a fibrous mesh that impeded the flow of blood
84
Define the intrinsic pathway and extrinsic pathway
```
In = exposed collagen + XII
Ex = Exposed tissue factor + VII
```
85
Define fibrinolysis
Clot dissolution
| Plasminogen and tPA bind to fibrin in blood clot
86
Define anticoagulant and name examples
A factor that opposes clot formation
| Examples are aspirin, heparin, oral anticoagulants
