Unit 4 - Cardiovascular System Flashcards
1
Q
What is the cardiovascular system composed of?
A
heart and system of vessels
2
Q
What is the main two functions of the cardiovascular system?
A
- contribute the blood to the tissues of the body
- flow the blood through the lungs for exchange of gases
3
Q
Where is the heart located?
A
Mediastinum - middle of the thoracic cavity, between two lungs
4
Q
What is the shape of the heart?
A
- rounded cranial end called the base of the heart
- apex of the heart is located at the caudal end
5
Q
How is the heart attached to the thoracic cavity?
A
Large arteries and pericardial sac
6
Q
What is the pericardial sac?
A
membrane that surrounds the heart and keeps it locked in place, contains fluid for lubrification
7
Q
What are the two components of the pericardium?
A
Visceral pericardium: adherent to the outer surface of the heart
Parietal pericardium: outer layer
in between lies the pericardium fluid
8
Q
What are the functions of the pericardium?
A
- limits motion of the heart
- keeps it from over-expanding
- reduces friction when the heart is beating
9
Q
What are the three layers of the heart?
A
Endocardium
Myocardium
Epicardium
10
Q
What is the function of the endocardium?
A
- innermost layer of the heart
- in direct contact with the blood
- line the chambers of the heart
- forms a double layer in the valves
11
Q
What is the function of the myocardium?
A
- placed underneath the endocardium
- consists of muscles fibers and connective tissue
- form the fibrous rings around the valves
12
Q
What is the function of the epicardium?
A
- outermost layer which includes connective tissue
- also considered part of the pericardium
13
Q
What are the two chambers of the heart?
A
Left atrium and right atrium
14
Q
What is the function of the atria?
A
receive blood from large veins to the heart
15
Q
How can the atria be identified from the outside of the heart?
A
by the auricles, blind pouches that look like “earflaps”
16
Q
What are the atria separated by?
A
interatrial septum
17
Q
What happens once the atria is full of blood?
A
atria wall contracts and pushes blood into the ventricles
18
Q
What are the two types of ventricles?
A
Left ventricle and right ventricle
19
Q
What is the function of the ventricles?
A
pump blood out from the heart and contain coronary blood vessels
20
Q
What are the ventricles separated by?
A
interventricular septum
21
Q
How are the ventricles visible from the outside of the heart by?
A
interventricular groove
22
Q
What is the groove that separates the atria from the ventricles?
A
atrioventricular groove
23
Q
What is the function of the septum?
A
Divides the heart into right and left sides, avoids mixing the oxygenated blood from the deoxygenated blood
24
Q
What can the septum of the heart be divided into?
A
Interatrial septum
Interventricular septum
25
Where are the four valves of the heart located?
two are located between the right and left atria and their respective ventricles
two are located between the right and left ventricles and the arteries they eject blood into
26
What are the names of the four valves of the heart?
Bicuspid valve
Tricuspid valve
Pulmonary valve
Aortic valve
27
What is the function of the bicuspid valve?
separates the left atrium from the left ventricle and has two leaflets
28
What is the function of the tricuspid valve?
Has three leaflets, separates the right atrium from the right ventricle
29
What are the valves of the heart connected to?
Connected to fibrous tissues called chrodae tendinae
Which are in turn attached to papillary muscles
30
What do the contraction of the heart valve muscles do?
Contraction of the chordae tendinae and the papillary muscles makes the valves open and close
31
What is the function of the pulmonary valve?
opening ad closing the pulmonary trunk
32
What is the function of the aortic valve?
opening at the aorta
33
What is the name/function for the aortic and pulmonary valves of the heart?
semilunar valves: ensure blood flows only from the ventricle into the artery,
34
What occurs in the valves when the ventricles relax and contract?
Relaxation: valve leaflets open to allow blood to flow from the atrium into the ventricle
Contraction: valve leaflets are forced closed
35
What is the function of the chordae tendinae?
prevent the margins of the valve from everything back into the atrium
36
How does the thickness of the heart walls vary?
aortic walls are thinner: shorter distance blood travel
left ventricle is thicker than right ventricle: pumps blood to a greater distance at higher pressure
37
What are some characteristics of the cardiac muscle?
- cell found only in the heart
- make up the myocardium
- contains 1-2 nuclei located near to the center of the cell
- contains involuntary contractions
38
What is the difference between skeletal vs cardiac muscle cells
cardiac can start a contraction on its own, skeletal contractions come from the CNS
39
How are the cardiac cells joined together?
intercalated discs
40
What is a gap junction?
channels that allow direct communication in the intercalated discs and rapid passage of ions and small molecules between adjacent cardiac muscle cell
41
What is the function of the gap junctions?
- facilitate the spread of electrical impulses from one cardiomyocyte to the next
- ensure synchronized contraction of the entire heart muscle
42
What are desmosomes?
a component of intercalated discs and are specialized structures that provide strong mechanical connections between adjacent cardiomyocytes
43
What is the function of desmosomes?
- component of intercalated discs, provide mechanical connections between adjacent cardiomyocytes
- anchor the cells together, preventing them from pulling apart during the intense contractions of the heart muscle
- contribute to the structural integrity of the heart tissue
44
How are cardiac muscles stimulated to contract?
have autorhythmic cells, one cardiac cell can stimulate the next cardiac cell
45
What are the five types of vessels?
Artery - large vessel
Arteriole - smaller branch of the artery
Capillary - smallest blood vessels in the vascular system
Venules - smaller branch of the vein
Veins - large vessel with valves
46
What are the three layers of arteries and veins?
Endothelium:
Smooth muscle and elastic fiber
Connective tissue and collagen fibers
47
What is the function of the endothelium layer of vessels?
the inner layer, which lines the lumen of the vessels, provides a smooth surface, low resistance for a smooth blood flow
48
Why do vessels have muscles?
dilate the vessels in temperature changes, and also regulate blood flow pressure
49
Why is the muscle layer thicker in arteries?
need to push more blood
50
What is the function of the smooth muscle and elastic fiber layer in vessels?
smooth muscle: contract and relax to change diameter of the vessel
elastic fiber: provide stretchability of the vessel
51
What is the function of the connective tissue and collagen fibers layer in vessels?
forms the outer layer, prevents the tearing of the vessel and keeps the lumen of the vessel open
52
What are the two types of arteries?
Elastic artery - greater elastic gibers in the middle layer
Muscular artery - great content of smooth muscles in the middle layer
53
What do the two types of arteries look like under a microscopic image?
elastic artery - has more fibers
muscular artery - has more smooth layers, less elastic at the top
54
What are some characteristics of elastic arteries?
- found closest to the heart
- have the greatest ability to stretch when blood passes through them
- the aorta is the largest elastic artery in the body
55
What are some characteristics of muscular arteries?
- found farther away from the heart
- in this case, blood surge is not severe enough to cause damage
- they are responsible to transport blood to organs and tissues, they branch into arterioles
56
What are some characteristics of veins?
- transport blood toward the heart
- walls are much thinner than arteries
- one-way valves open in the direction of the heart and close to prevent back flow
57
What is circulation to the lungs called?
pulmonary circulation
58
What is circulation to the rest of the body called?
systematic circulatin
59
What are the two types of pumps that the heart has?
1. Low-pressure pump: direct blood from the body to the lungs (pulmonary circ)
2. High-pressure pump: distributes blood to the systematic circ
60
What are the steps to blood flow throughout the heart?
- right atrium receives deoxygenated blood from systematic circulation
- right ventricle receives deoxygenated blood from right atrium and sends it out to the pulmonary circulation for oxygenation
- left atrium receives freshly oxygenated blood back from the pulmonary circulation
- the left ventricle receives the oxygenated blood from the left atrium and sends it to systematic circulation
61
What are some characteristics of the cardiac conduction system?
- the presence of autorhythmic cardiac muscle cells
- specialized cardiac muscle fibres that generate an action potential (electrical pulse)
- initiates the cardiac cycle
62
What are pacemaker cells?
cells able to generate an electrical pulse
63
What are the components of the cardiac conduction system?
- sinoatrial node
- atrioventricular node
- Purkinje fibers
- bundle branches (bundle of his)
64
What is the function of the sinoatrial nodes?
generate their own action potential, initiates the impulse at the right atrium, impulses spreads across both atria, causing contraction to push blood to the ventricles
65
What is the function of the atrioventricular node?
connectsthe electrical systems of the atria and te ventricles
once received at the AV node, the impulse is delayed, it permits the atria to complete the contraction before the ventricular contraction occurs
66
What is the function of the bundle of his?
fibers of the bundle of his travel down the interventricular septum to the apex of the heart
67
what is the function of the purkinje fibers?
impulses received are directed into the right and left ventricular myocardium
68
What is polarization?
When the cardiac muscle cells are at rest
69
What are some characteristics of polarization/depolarization of impulsing of the cardiac conduction system?
- sodium and calcium are located on the outer membrane of the cell while potassium is located inside
- charge on one side of the membrane is different than the other side of the membrane
- charges can change
70
What is depolarization?
needed for contraction to occur,
step 1: Na+ and Ca2+ ions moves through channels in the cell membrane from the exterior to the interior of the cell, it reverses the polarity of the cell membrane
step 2: K+ ions move through channels in the cell membrane from the interior-exterior - restores the original polarity, but now the Na+ Ca2+ and K+ ions are on the wrong sides of membrane
step 3: repolarization
71
What is repolarization?
ions are pumped back to their original located, it gets the cells ready for the next depolarization
72
what are the two portions to the circulatory system
Pulmonary (lung) circulation - right side of the heart, receives deoxygenated blood from throughout the animals body (carried in veins) and pumps it out to the lungs where it becomes oxygenated
Systemic (body) circulation - left side of the heart, receives oxygenated blood from the lungs and pumps it out to the rest of the animals body
73
where is the heart located?
the middle of the thoracic cavity in the mediastinum, the space between the two lungs
74
how is the mediastinum bound?
bounded to thoracic inlet cranially
diaphragm caudally
sternum ventrally
spinal column dorsally
75
what is the pericardium divided into?
pericardial sac and serous pericardium
76
what are the two membranes that the serous pericardium consists of?
parietal layer of the serous pericardium - lines the pericardial sac
visceral layer of the serous pericardium - lies directly on the surface of the heart
77
what is the pericardial space?
area between the visceral pericardium and parietal pericardium
78
What is in the pericardial space?
pericardial fluid that lubricates the two membranes and prevents friction as they rub together during contractions and relaxations of the heart
79
what are cardiac muscle joined by?
Cardiac muscle fibers are joined side-to-side by multiple branches and end-to-end by intercalated discs
80
What is the function of the skeleton of the heart?
- Separates the atria and ventricles
- Anchors the heart valves
- It provides a point of attachment for the myocardium
- Provides some electrical insulation between the atria and the ventricles
81
Where is the skeleton of the heart located?
between the atria and the ventricles
