Heart and Vessels Flashcards
0
Q
ather/o
A
fatty substance
1
Q
arter/o, arteri/o
A
artery
2
Q
atri/o
A
atrium
3
Q
cardi/o
A
heart
4
Q
coron/o
A
heart
5
Q
pericardi/o
A
pericardium
6
Q
rhytm/o
A
rhythm
7
Q
sphygm/o
A
pulse
8
Q
steth/o
A
chest
9
Q
vas/o
A
vessel
10
Q
vascul/o
A
vessel
11
Q
ven/o, ven/i
A
vein
12
Q
ventricul/o
A
ventricle
13
Q
pericardial sac (parietal pericardium)
A
anchors heart to great vessels (aorta and venae cavae)
14
Q
epicardium (visceral pericardium)
A
serous membrane covering heart’s surface
secretes pericardial fluid
15
Q
myocardium
A
heart’s middle layer composed of cardiac muscle tissue
16
Q
endocardium
A
heart’s inner most layer, lines the 4 chambers of the heart
17
Q
coronary sulcus
A
marks separation of atria from ventricles
18
Q
interventricular sulcus
A
mark separation of left and right ventricles
19
Q
interatrial septum
A
separates two atria from each other
20
Q
interventricular septum
A
separate ventricles from one another
21
Q
pulmonary circuit
A
heart pumping blood to the lungs and back
CO2 is unloaded and O2 is loaded
22
Q
systemic circuit
A
once blood is returned from lungs, left side of heart pumps blood to all parts of body to be returned back to heart
O2 is unloaded and CO2 is loaded
23
Q
Steps of cardiac conduction system
A
- heartbeat started by SA node
- from SA node, cardiac muscle cells carry electrical impulse across myocardium of both atria causing depolarization
- while step 2 happens, other cardiac cells cary impulse to AV node
- AV bundle carries impulse down interventricular septum to apex
- Purkinje fibers fan out from AV bundle stimulating cardiac muscle cells to depolarize and contract
24
Phases of cardiac cycle
1. Atrial systole: SA node fires, atria depolarize and contract together. increased pressure pushes blood through AV valves to ventricles
2. Atrial diastole: atria repolarize and relax. pressure in superior/inferior venae cavae and pulmonary veins is greater than atrial pressure so blood rushes in
3. Ventricular systole: once impulse is carried from AV node to purkinje fibers ventricles depolarize and contract together. chordae tendinae also contract to prevent backflow. contraction of ventricles decreases volume and increases pressure inside ventricles. blood pushed through pulmonary and aortic valves.
4. Ventricular diastole: ventricles repolarize and relax. blood moves from AV valves to ventricles from atria. all 4 chambers fill with blood during this phase. atria are not contracting during this phase. blood is passively moving from atria to ventricles due to difference in pressure
25
sinus rythm
normal pace, with 70-80 bpm
26
vagal tone
a pace normally kept in check by autonomic nervous system through vagus nerve
27
ectopic focus
occurs when any part of conduction system other than SA node sets pace
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nodal rhythm
occurs if AV node is ectopic focus
29
P wave
shows depolarization of atria
30
Q, R, S waves
together represent ventricles depolarizing
31
T wave
represents ventricles repolarizing
32
What event does normal ECG not show?
atria repolarizing; this happens the same time ventricles are depolarizing which is a much stronger event
33
cardiac output
amount of blood ejected by each ventricle of the heart each minute
calculated by multiplying heart rate by stroke volume
34
stroke volume
amount of blood ejected from each ventricle per beat
35
cardiac reserve
difference between the cardiac output of a heart at rest and the maximum cardiac output the heart can achieve
36
3 factors that affect stroke volume
preload: amount of tension in the myocardium of ventricular walls
contractility: responsiveness of cardiac muscle to contract
afterload: concerns pressure in pulmonary trunk and aorta during diastole
37
frank-starling law of heart
states heart must pump out the amount of blood it receives
38
chronotropic factor
anything that changes the heart rate
| positive increase heart rate, negative decrease heart rate
39
cardiac accelerator center
uses sympathetic neurons to stimulate the SA and AV nodes to speed up heart rate
40
cardiac inhibitory center
uses parasympathetic neurons of vagus nerve to keep SA node at 70-80 bpm (vagal tone)
if vagus nerve is severed, SA node typically sets pace at 100/bpm
41
3 types of sensors that feed information to centers in medulla oblongata
proprioceptors, baroreceptors, chemoreceptors
42
proprioceptors
located in body's muscles, joints, and tendons
| information they send alerts centers to any change in body's activity level
43
baroreceptors
located in aorta and carotid arteries
alert the centers to any changes in bp
if bp falls, cardiac accelerator center stimulates SA and AV nodes to increase heart rate in an effort to restore bp to homeostasis
44
chemoreceptors
monitor pH, carbon dioxide and oxygen in blood
located at aortic arch, on carotid arteries, and in medulla oblongata
much more important for setting respiratory rate
45
chronotropic effects of chemicals
positive effects: epinephrine, caffeine, norepinephrine, nicotine, and thyroid hormone
negative effects: potassium ions
46
arteries
carry blood away from heart to capillaries
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capillaries
allow for exchange of materials between blood and tissues
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veins
deliver blood from capillaries back to heart
49
tunica externa
outermost layer of vessel wall
50
tunica media
middle layer of vessel wall
thickest layer
more muscular in arteries than veins of comparable size
may be elastic fibers in this layer depending on vessel
51
tunica interna
lining of vessel wall
| vital that this layer be smooth and secrete chemical to repel platelets
52
conducting arteries
largest of the arteries (aorta, pulmonary arteries, etc)
carry blood away from heart
need to withstand high pressure, therefore have most muscle/elastic fibers in their walls for expansion
53
distributing arteries
medium-sized
distribute blood away from conducting arteries to organs
examples are hepatic artery, and renal arteries
54
resistance arteries
smallest of the arteries
| examples are arterioles that deliver blood to capillaries
55
coronary route
heart's own circulation route composed of coronary arteries and veins
right and left coronary arteries lead to capillary beds in heart's tissue
20% of blood from capillaries directly returned to R atrium of heart
56
systemic route
carry blood from heart to tissues in the body and back again
57
what are the 2 types of alternative routes?
portal routes and anastomoses
58
portal routes
contains 2 capillary beds before blood is returned to heart
allows materials to be exchanged twice between blood and tissues before returning to heart
example: hepatic portal route
59
hepatic portal route
route between intestines and liver
blood travels from heart to arteries to capillary beds in sm intestine/other digestive organs. digested nutrients absorbed into blood through capillaries. blood travels through small veins leading to hepatic portal vein to capillary beds in liver, where nutrients are processed. blood exits liver via hepatic vein on its way back to heart.
60
anastomoses
involves vessels merging together
| 3 types
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arteriovenous anastomoses
often called a shunt
merges an artery with a vein, skipping capillary bed
used in fingers, palms, toes and ears in condition of extreme cold
protective mechanism to avoid losing heat
62
arterial anastomoses
merges 2 arteries together to provide collateral routes to same area
can be found in heart, to make sure all parts of heart are adequately fed, and at joints, where movement may block one of routes
63
venous anastomoses
most common anastomoses
| merges veins to drain an organ
64
venous return
5 mechanisms aid in venous return:
| pressure gradient, gravity, thoracic pump, cardiac suction, skeletal muscle pump
65
pressure gradiant
pressure in veins due to action of heart propels blood toward heart
66
gravity
blood moves through veins above heart due to gravity and flows downhill
67
thoracic pump
chest expands every time breath is inhaled increasing the volume and decreasing pressure within chest
as air rushes into lungs to equalize pressure, blood in veins in abdominal cavity is sucked into inferior vena cava
68
cardiac suction
atria return to shape during atrial diastole creating less pressure in atria than in superior and inferior venae cavae and pulmonary veins, so blood is sucked into atria
69
skeletal muscle pump
especially effective in limbs
| skeletal muscle action massages blood through the veins, while valve in veins prevent backflow
70
What 3 ways does resistance make a difference in terms of blood pressure?
viscosity (thickness): amount of albumins and RBCs determine blood thickness
vessel length: the greater the vessel length, the more friction that occurs between blood and vessel walls. friction slows blood.
vessel radius: the smaller the radius, the more blood comes in contact with walls of vessel. radius can be controlled in several different ways to regulate bp (vasodilation/vasoconstriction)
71
pulse pressure
indicates the surge of pressure small arteries must withstand with each ventricular contraction
equation: sytolic pressure minue diastolic pressure (in mmHg)
pulse pressure increases as stroke volume increases
72
mean arterial pressure (MAP)
average pressure arteries must be able to withstand
| determined by equation: diastolic pressure plus 1/3 of pulse pressure
