Cardiovascular System Flashcards
1
Q
What are the functions of the cardiovascular system?
A
To provides a pump (the heart) that circulate the fluid (the blood) and a series of conduction hoses (the blood vessels) that carry it throughout the body
2
Q
What do arteries do?
A
carry blood away from the heart
3
Q
What do veins do?
A
return blood to the heart
4
Q
What are capillaries?
A
they form a bed connecting the smallest arteries (arterioles) and veins (venuoles)
5
Q
What does the pulmonary system include?
A
Blood to and from the lungs
6
Q
What does the systemic system include?
A
Blood to and from the rest of the body
7
Q
What are valves?
A
Mechanical devices that permit the flow of blood in one direction only
8
Q
What are the atrioventricular valves?
A
tricuspid and bicuspid valve
9
Q
What are the other names for the bicuspid valve?
A
left AV valve, mitral valve
10
Q
What is the other name for the tricuspid valve?
A
right AV valve
11
Q
What are the semilunar valves?
A
halfmoon shaped flaps, includes pulmonary semilunar valve and aortic semilunar valve
12
Q
Where is the pulmonary semilunar valve located?
A
At the entrance of the pulmonary artery
13
Q
Where is aortic semilunar valve located?
A
At the entrance of the aorta
14
Q
What are cardiac muscles wrapped by?
A
a strong but elastic sheath, and adjacent cells are tied together by fibrous cross links
15
Q
What does the fibrous skeleton of the heart consist of?
A
Four dense bands of tough, elastic tissue that encircle the bases of the pulmonary trunk and aorta and the heart valves
16
Q
What are the 5 classes of blood vessels and describe them:
A
- arteries: carry blood away from the heart
- arterioles: are smallest branches of arteries
- capillaries: are the smallest blood vessels and are located between blood and interstitial fluid
- venules: collect blood from capillaries
- veins: return blood to heart
17
Q
What are the three layers of arteries and veins?
A
tunica adventitia, tunica media, tunica interna (includes the endothelial lining a connective tissue layer)
18
Q
What are the functions of capillaries?
A
- location of all exchange functions of cardiovascular system
- materials diffuse between blood and interstitial fluid
19
Q
What are the structures of capillaries?
A
- endothelial tube, inside thin basal lamina
- no tunica media
- no tunica externa
- diameter is similar to red blood cell
20
Q
What are the three types of capillaries?
A
- continuous capillaries
- fenestrated capillaries
- sinusoids
21
Q
What is the structure of continuous capillaries?
A
- complete endothelial lining
- small solutes and water
- all tissues except epithelial and cartilage
22
Q
What are the functions of continuous capillaries?
A
permit the diffusion of:
- water
- small solutes
- lipid-soluble materials
block:
- blood cells
- plasma proteins
23
Q
What are the structures of fenestrated capillaries?
A
pores, endocrine organs (kidneys, intestinal tract)
24
Q
What are the functions of fenestrated capillaries?
A
permit the rapid exchange of water and larger solutes
25
What is the structure of sinusoids?
they have gaps between adjacent endothelial cells
26
What do sinusoids do?
permit free exchange of water and large plasma proteins
27
Where are sinusoids located?
liver, spleen, bone marrow, endocrine glands
28
What are arteriovenous anastomosis?
direct connections between arterioles and venules. They bypass the capillary valve
29
What is the capillary sphincter?
It guards the entrance to each capillary. It opens and closes, causing capillary blood to flow in pulses
30
What is vasomotion?
the contraction and relaxation cycle of capillary sphincters. It causes blood flow in capillary beds to constantly change routes
31
What does the capillary blood or plexus do?
usually connects 1 arteriole and 1 venule
32
How is blood distributed?
the total blood volume is unevenly distributed among arteries, veins, and capillaries. Heart, arteries, and capillaries: 30-35% of blood volume & venous system: 60-65%. 1/3 of venous blood is the large venous networks of the liver, bone marrow, and skin (the venous reserve)
33
What is a heartbeat?
a single contraction of the heart
34
What is the series of a heartbeat?
first the atria, then the ventricles, in a coordinated manner so that blood flows in the right direction at the proper time
35
What are the types of cardiac muscle cells?
conducting system: controls and coordinates heartbeat
contractile cells: produce contractions
36
What is the conducting system?
A system of specialized cardiac muscles cells. It initiates and distributes electrical impulses that stimulate contraction. It also has automaticity, meaning that the cardiac muscle tissue contracts automatically
37
What are the parts of the conducting system and where are they located?
- sinoatrial (SA) node: located in the wall of the right atrium
- atrioventricular (AV) node: located at the junction between the atria and ventricles
- conduction cells: innterconnect the two nodes and distribute the contractile stimulus throughout the myocardium
38
What do the conducting cells include?
- internodal pathways
- AV bundle
- bundle branches
- purkinje fibers
39
What is prepotential - sinoatrial?
Also called the pacemaker potential, is the resting potential of conducting cells (leaking channels, gradually depolarizes toward threshold). SA node depolarizes first, establishing heart rate.
40
Describe the heart rate.
- SA node generates 60-11 action potentials per minute --> pacemaker
- sympathetic neurons can increase the rate of depolarization of SA node and increase heart rate: parasympathetic stimulation slows heart rate
- AV node generates 40-60 action potentials per minute
41
Describe impulse conduction through the heart (AV).
- the action potential of SA nodes affects only the atria
- AV nodes takes about 100 msec for the impulse to pass through the AV node and enter the AV bundle
42
What is the relevance of defibrillation?
- some disease hearts develop one or more ectopic pacemakers (other than SA node)
- cardiac msucle cells receive action potentials from more than one direction
- the defibrillator sends a large electrical current of short duraction to repolarized all the cells at the same time and resume the SA as pacemaker
43
What are contractile cells?
form the bulk of the atrial and ventricular walls and produce the powerful contractions that propel blood. 99% of muscles in the heart
purkinje fibers distribute the stimulus to the contractile cells in ventricles
44
Describe the three steps of action potentials in contractile cells.
step 1. rapid depolarization
- voltage-regulated sodium channels (fast) open
step 2. the plateau
- voltage-regulated calcium channels (slow) open
- the presence of a plateau is the major difference between action potentials in cardiac and skeletal muscle fibers
step 3. repolarization
- slow potassium channels open
- the refractory period: long, so no tetanic contractions
45
What is an electrocardiogram (ECG or EKG)?
- a recording of electrical events in the heart
- obtained by electrodes at specific body locations
- abnormal patterns diagnose damage
46
What are the important landmarks of an ECG?
- P wave: atria depolarize
- QRS complex: ventricles depolarize
- T wave: ventricles repolarize
47
What are the 4 phases of the cardiac cycle?
1. atrial systole (contraction)
2. atrial diastole (relaxation)
3. ventricular systole
4. ventricular diastole
48
What are the 6 steps in the cardiac cycle?
1. atrial systole
- atrial contraction begins
- right and left AV valves are open
- atria eject blood into ventricles: filling ventricles
2. atrial systole ends:
- ventricles contain maximum volume
- atrial diastole begins
3. ventricular systole:
- pressure in ventricles rises
- AV valves shut
- isovolumetric ventricular contraction
4. ventricular ejection:
- semilunar valves open
- blood flows into pulmonary and aortic trunks
5. ventricular diastole
- ventricular pressure falls
- semilunar valves close
- ventricular pressure is higher than atrial pressure
- all heart valves are closed
- ventricles relax (isovolumetric relaxation)
6. atrial pressure is higher than ventricular pressure:
- AV valves open
- passive atrial filling
- passive ventricular filling
- cardiac cycle ends
49
What is the effect of having a valvular insufficiency for the right AV valve?
- AKA tricuspid regurgitation
- fatigue
- irregular heart rhythms (arrhythmias)
- pulsing in the neck (jugular groove)
- shortness of breath with activity
- swelling in the belly area (abdomen), legs or neck veins
50
What is the effect of having a valvular insufficiency for the left AV valve?
- AKA mitral regurgitation
- irregular heart rhythms (arrhythmias)
- shortness of breath especially when in decubit (dorsal, laterla, or sternal)
- swollen manus or pes
51
What is end-diastolic volume (EDV)?
the amount of blood in each ventricle at the end of ventricular diastole
52
What is end-systolic volume (ESV)?
the amount of blood remaining in each ventricle at the end of ventricle systole
53
What is stroke volume (SV)?
the amount of blood pumped out of each ventricle during a single beat, SV = EDV - ESV
54
What is ejection fraction?
the percentage of the EDV represented by the SV: (SV/EDV) X 100 (60% in rest)
55
What is cardiac output (CO)?
the amount of blood pumped by each ventricle in 1 minute
56
What is the equation for cardiac output?
CO (ml/min) = SV (ml/beat) X HR (beats/min)
57
What is circulatory pressure?
the pressure difference between the base of the ascending aorta and the entrance to the right atrium
58
What are the three components of circulatory pressure?
1. blood pressure
- refers to arterial pressure
- in humans, 100 to ~35 mm Hg (the start of a capillary network(
2. capillary hydrostatic pressure (CHP)
- the pressure within capillary beds, 35 to 18 mmHg
3. venous pressure
- the pressure within the venous system, ~ 18 mm Hg
59
What is millimeters of mercury (mm Hg)?
normal atmospheric pressure is approximately 760 mm Hg
60
What is systolic pressure?
the peak blood pressure during ventricular systole
61
What is diastolic pressure?
the minimum blood pressure during ventricular diastole
62
What is pulse pressure?
- the difference between these two blood pressures (systolic and diastolic pressure)
- become smaller as the distance from the heart increases; not exist in capillaries
63
What is mean arterial pressure (MAP)?
MAP = diastolic pressure + (pulse pressure/3)
64
What is autoregulation?
When local factors change the pattern of blood flow within capillary beds in response to chemical changes in interstitial fluids
65
What do central neural mechanisms do?
they respond to changes in arterial pressure or blood gas levels
66
What do hormones do?
- short-term adjustments: changes in cardiac output and peripheral resistance
- long-term adjustments: changes in blood volume that affect cardiac output and pas transport
67
What are the three cardiovascular centers of medulla oblongata and what do they do?
1. cardioacceleratory center
- controls sympathetic neurons
- increase heart rate
- produces more power contractions (reduces the ESV)
2. cardioinhibitory center
- controls parasympathetic neurons
- slow heart rate
- reduces the contractile strength (increases the ESV)
3. vasomotor centers
- control the activity of sympathetic motor neurons
- control vasoconstriction of peripheral vessels in most tissues and vasodilation in skeletal muscles and brain
68
What are the 3 shunts of fetal circulation?
ductus venosus
ductus arteriosus
foramen ovale
69
What are the additional parts of fetal circulation?
umbilical vein
umbilical artery
70
Where can you take an animal's pulse?
dog or cat - femoral artery
horse - digital or mandible artery
71
What are the best sites for venipuncture?
dog or cat - external jugular, cephalic vein, lateral saphenous vein
large animals - external jugular
cattle - tail vein = medial caudal vein
pig - jugular or ear vein
birds - jugular vein
