cardiovascular system Flashcards
1
Q
what does the circulatory system do?
A
pumps and directs blood cells and substances carried in blood to all tissues of the body
2
Q
the circulatory system includes the _________ and ____________ _____________ ___________.
A
blood and lymphatic vascular system
3
Q
the components of the circulatory system
A
- heart
- arteries
- capillaries (microvasculature)
- veins
4
Q
what is the lymphatic system?
A
the system that connects with the vascular system that carry lymph and return fluid from tissue spaces all over the body to the blood
5
Q
the cardiovascular system includes what 2 types of circulation?
A
- pulmonary
- systemic
6
Q
the pulmonary circulation
A
- carries deoxygenated blood from the right side of the heart to the lungs
- after being oxygenated, the blood travels back to the left side of the heart
7
Q
the systemic circulation
A
pumps blood from the left side of the heart to the head, limbs, rest of body, and back to the right side of the heart
8
Q
the function of the heart in the circulatory system
A
propel blood throughout the system
9
Q
the function of the arteries in the circulatory system
A
a series of vessels that carry blood to the tissues and becomes smaller as they branch into organ
10
Q
the high pressure system
A
arteries (thicker walls)
11
Q
the low pressure system
A
veins
12
Q
what controls blood pressure?
A
arterioles
13
Q
the function of the capillaries in the circulatory system
A
the smallest vessels that are the site of gas, nutrient, and waste exchange
14
Q
the function of the veins in the circulatory system
A
a series of venules that bring blood to the heart and get bigger as they get closer to the heart
15
Q
what kind of epithelium lines the cardiovascular system internally?
A
simple squamous epithelium (cardiac and vascular endothelium)
16
Q
capillaries are made almost entirely of
A
a single layer of endothelial cell and associated pericytes
17
Q
the heart develops embryonically from
A
a simple blood vessel
18
Q
at the beginning of the 3rd week, blood vessel formation begins in the
A
extraembryonic mesoderm of the umbilical vessel, connecting stalk, and chorion
- embryonic blood vessels develop 2 days later
19
Q
the mesoderm gives rise to
A
- connective tissue
- cartilage
- bone
- striated smooth muscle
- HEART
- BLOOD
- LYMPHATIC VESSELS
- kidneys
- ovaries
- testes
- genital ducts
20
Q
the myocardium of the ventricular walls is ___________ than that of the atria
A
thicker!
21
Q
the layers of the heart
A
- endocardium
- myocardium
- epicardium
~~pericardium~~
22
Q
the endocardium
A
- in contact with the blood inside the heart
- is homologous to the tunica intima
- thicker in atria than ventricles
23
Q
the myocardium
A
- is homologous to the tunica media
- forms the bulk of the heart wall
- consists mostly of cardiac muscle
- thickest layer
24
Q
the epicardium
A
- the outer layer
- homologous to the tunica adventitia
- has 2 layers
- loose fatty connective tissue
25
the mesothelium
one layer of squamous to cuboidal mesothelial cells
- line pleural and peritoneal cavities
26
the pericardium
- fibroelastic
- fluid-filled sac
- has outer parietal layer that reflects onto the heart surface as a visceral layer
- similar to pleura of peritoneum
27
the valves of the heart are
- flaps
- connective tissue
- anchored in heart's dense connective tissue
- prevent backflow of blood
28
the fibrous tissue of the heart includes
- chordae tendinae
29
chordae tendinae
- cords that extend from the cusps of both AV valves
- attach to papillary muscles
- prevent valves from turning inside out during contraction
30
subendocardial layer of the heart includes
- loose connective tissue
- small blood vessels
- nerves
- purkinje fibers
31
atrial _________ is thicker than ventricles
endocardium
32
ventricular __________ is thicker than in the atria
myocardium
33
the atrioventricular valves are:
- mitral (bicuspid - left side)
- tricuspid (right side)
- located between atria and ventricles
34
the semilunar valves
- are aortic and pulmonary
- control the outflow from the ventricles to the arteries
35
valves are made of
- dense connective tissue
- contains lots of elastic tissue
- contains endothelium of blood and lymphatic vessels
36
what is the conduction system?
the system that initiates the electrical impulse for contraction (heartbeat) and spreads it through the ventricular myocardium
37
characteristics of the conduction system
- excitable
- modified cardiomyocytes
- cardiomyocytes contract in non synchronized/involuntary manner
38
the sinoatrial (SA) node
- pacemaker
- in the wall of the right atrium
- sets tone for the rest of the contraction of the heart
- connects AV node in the floor of the atrium
- delays conduction
39
purkinje fibers
- modified cardiac muscle joined by intercalated disks
- specialize in impulse conduction rather than contraction
- paler stain
- sit close to the endothelium
40
the AV bundle (of His)
- gives rise to right and left bundle branches that run along the interventricular septum to the apex of the heart
- connected with AV node
41
AV node
- consist of myocardial tissue
- connected with AV bundle
42
the layers of the blood vessels
- tunica intima
- tunica media
- tunica adventitia
43
tunica intima
- endothelium (simple squamous on basal lamina)
- subendothelial loose connective tissue
- internal elastic lamina
- fenestrated sheet for diffusion
- prominent in muscular arteries
44
tunica media
- smooth muscle (secretion, elastic fibers, reticular fibers)
- much thicker in arteries than veins (more elastin)
45
tunica adventitia
- fibroblasts + collagen + loose elastic connective tissue
- vasa vasorum (nutrients from lumen and vessels)
- nervi vasorum
- vasoconstriction/vasodilation
- lymphatics
46
what is the vasa vasorum?
microvasculature to bring oxygen and nutrients to local cells that are too far from lumen
- supply nutrients to the larger arteries and veins
47
what comprises the vasa vasorum?
- arterioles
- capillaries
- venules
48
walls of all blood vessels except capillaries contain:
- smooth muscle
- connective tissue
- endothelial lining
49
the amount and arrangement of the tissues of blood vessels are influenced by
metabolic factors
50
the endothelium
- specialized epithelium
- semipermeable barrier between blood and interstitial fluid
51
functions of endothelium (other than exchange between blood and tissues)
- present nonthrombogenic surface
- regulate local tone and blood flow
- inflammation and local immune responses
52
blood vessel layers correspond to heart layers
53
classification of arteries
- elastic arteries
- muscular arteries
- arterioles
54
elastic arteries
- includes aorta and major branches
- elastic lamina between secretory VSMCs
- yellow
- receive blood from heart
55
atherosclerosis is mainly associated with
elastic and muscular arteries
56
muscular arteries
- have prominent wavy internal elastic lamina supporting rest of intimal layer
- layers of VSMC's
- external elastic lamina
- more smooth muscles in tunica media
57
arterioles
- small arteries
- may or may not have internal elastic lamina
- 2-5 layers of VSMCs
- no external elastic lamina
58
VSMCs secrete
- elastin
- collagen
- proteoglycans
59
blood flow into capillary beds
elastic arteries > muscular arteries > arterioles > capillaries > postcapillary venules
60
blood flow into capillary beds
- supplied by arterioles
- drain into venules
61
blood flow to capillary beds are bypassed in the skin by
arteriovenous (AV) shunts
62
capillaries are composed of
- endothelium
- nuclei bulge into lumen
- pinocytotic vesicles
- no smooth muscle except pericytes
- can differentiate into smooth muscle and endothelial cells during injury
63
types of capillaries
- continuous
- fenestrated
- sinusoids
64
continuous capillaries
- most common
- tight junctions
- minimal fluid leakage
- diffused or transcytosis
- common in brain and muscles
- continuous basement membrane
65
fenestrated capillaries
- tight junctions but have fenestrations
- greater exchange across endothelium
- basement membrane is continuous and contains a diaphragm
- found in organs where molecular exchange with blood is important
- choroid plexus, intestinal walls, endocrine organs
66
sinusoids
- larger in diameter
- discontinuous
- larger perforations
- partial, discontinuous basement membrane
- found in organs where exchange of macromolecules and cells occur readily between tissues and blood
- bone marrow, liver, spleen
67
components of veins
- 70% total blood within veins
- larger
- skeletal muscle helps drive the blood upwards (acts like pump)
68
3 tunics of veins
- poorly defined tunica media
- poorly defined boundaries between intima and media
- well developed tunica adventitia
69
postcapillary venules
- larger and more organized than capillaries and veins
- have large lumens and an intima of simple endothelial cells with occasional pericytes
- thin walls
- WBCs and integrins leave via postcapillary venules
70
what triggers atherosclerosis?
high circulating levels of low-density lipoproteins (LDL) damage arteriole endothelium
71
the lymphatic vessels converge into 2 large trunks called:
the thoracic duct and the right lymphatic duct
- these empty back into the blood
72
microcirculation of the dental pulp
- consist of end arteries running into the tissue through a small apical foramen
- leave pulp as venules
- vasculature surrounded by loose CT in rigid dentin walls
73
the lack of collateral circulation and limited ability to expand can cause
special physiological circulatory implications
74
the resting pulpal blood flow is about ______ higher than resting skeletal muscle
4x
75
the capillaries of the dental pulp have what kind of endothelium?
continuous endothelium except in odontoblastic area where it can be fenestrated
76
the interstitial space acts as
a transport medium and fluid reservoir
77
part of the vascular resistance regulating blood flow is located in
(related to teeth)
the arteries before entering the pulp and in the venules after leaving the pulp
78
how is blood flow regulated in the tooth during sympathetic trunk activation
- has an effect on pulpal blood flow (PBF)
- alpha-adrenergic receptors are identified in the pulp
- stimulation of cervical sympathetic trunk
- vasoconstriction and fall in blood flow in pulp
- neuropeptide Y induces vasoconstriction in the pulp
79
under normal conditions vascular tone is controlled by:
- nerves
- local and humoral mechanisms that maintain the vessels in a state of partial constriction
- neighboring tissues
80
what can activate the sympathetic trunk affecting blood flow in the pulp?
anxiety/fear of going to the dentist
81
the AV shunts affect
nerves or pulpal blood flow
82
changes in circulation of what tissues can affect pulp circulation?
- gingiva
- periodontal ligament
- alveolar bone
