cardiovasuclar Flashcards
1
Q
why do we have a cardiovascular system
A
to provide oxygen and nutrients and remove wastes like carbon dioxide from cells
2
Q
hemodynamics
A
the study of blood flow
relationship between blood flow, pressure, and resistance to blood flow
3
Q
flow equation
A
flow = change in pressure/resistance to flow
4
Q
what must occur to have flow
A
the pressure difference must overcome resistance to flow P>R
5
Q
hydrostatic pressure
A
the pressure that the volume of blood within out circulatory system exerts on the walls of the blood vessels that contain it
6
Q
factors that determine resistance to blood flow
A
viscosity of the blood, length of the blood vessel, diameter of the blood vessel
7
Q
viscosity
A
the friction between molecules of a flowing fluid
8
Q
heamtocrit
A
the number of red blood cells in the blood
9
Q
resistance equation
A
r = 8ln/pi r^4
l = vessel length
n = blood viscosity
r = inside radius of vessel
— very small changes in vessel diameter can lead to large changes in resistance —
10
Q
function of the cardiovascular system
A
- deliver oxygen and nutrients and remove waste products of metabolism
- fast chemical signaling to cells by circulating hormones or neurotransmitters
- thermoregulation
- mediation of inflammatory and host defense responses against invading microorganisms
11
Q
components of the cardiovascular system
A
heart
blood vessels
blood
12
Q
vessels
A
arteries, arterioles, capillaries, venules, veins
13
Q
arterioles
A
small branching vessels with high resisitance
14
Q
capillaries
A
transport of blood between small arteries and veins
- exchange materials between blood and cells in the body
15
Q
atria
A
thin-walled low pressure chambers, receive blood returning back to the heart
16
Q
ventricles
A
thick-walled chamber, forward propulsion of blood
17
Q
apex of heart
A
the lowest superficial surface of the heart
18
Q
base of heart
A
the upper surface of the heart where the blood vessels attach
19
Q
septa
A
muscular wall that separates the left and right sides of the heart
20
Q
interatrial septum
A
separates left and right atria
21
Q
interventricular septum
A
separates left and right ventricles
22
Q
pulmonary circuit
A
carries blood to and from the gas exchange surfaces of the lungs
23
Q
systemic circuit
A
transports blood to and from the rest of the body
24
Q
pericardium
A
a fibrous sac surrounding the heart and the roots of the great blood vessels leading into and out of the heart
- functions:
stabilizes the heart in the thoracic cavity
provides protection to the heart by physically surrounding it
reduces friction as the heart beats by secreting the pericardial fluid
limits overfilling of the heart chambers
25
fibrous pericardium
outer layer of the pericardial sac
provides protection for the heart and stabilizes the heart in the thoracic cavity by attaching to structures in the chest, holds heart in place, prevents overfilling of heart
26
parietal pericardium
part of the serous pericardium
lies underneath the fibrous pericardium and is attached to it
27
visceral pericardium
part of the serous pericardium
innermost layer of the pericardial sac
called the epicardium when it comes into contact with the heart muscle
28
pericardial cavity
separates the parietal pericardium from the visceral pericardium
29
serous layer
a layer composed of cells that secrete fluid
30
pericarditis
inflammation of the pericardium caused by viruses, bacteria, fungi, trauma or malignancy
leads to fluid accumulation in the pericardial cavity
31
cardiac temponade
compression of heart chambers due to excessive accumulation of pericardial fluid
heart's movement is limited and heart chambers cannot fill with adequate amount of blood
32
3 layers of heart wall
epicardium
myocardium
endocardium
33
epicardium
aka visceral pericardium
layer immediately outside the heart muscle and covers the outer surface of the heart; a protective layer
attached to myocardium with connective tissues
34
myocardium
the muscular wall of the heart underneath the epicardium
contains muscle cells or myocytes which contract and relax as the heart beats
35
endocardium
innermost layer of the heart wall that lines heart cavities and the heart valves; a thin layer of endothelium which is continuous with the endothelium of the attached blood vessels
36
myocytes
cardiac muscle cells
branched or y shaped
joined longitudinally or end to end to adjacent myocytes
striated or stripped appearance (actin and myosin)
has a single centrally located nucleus
rich in mitochondria (ATP)
adjacent cells are held together by intercalated disk
37
2 types of specialized intercellular junction at intercalated disks
desmosomes
gap junction
38
desmosomes
adhering junctions that hold cells together in tissues subject to considerable mechanical stress or stretching
mechanically couple one heart cell to another
proteins involved: cadherins, plaques, intermediate filaments
39
gap junction
communicating junctions that electrically couple heart cells, allowing ions to move between cells proteins involved: connexons
40
atrioventricular (AV) valves
found between the atria and the ventricles on both the left and right sides of the heart
- on left side: bicuspid or mitral valve
- on right side: tricuspid
41
semilunar (arterial) valves
found between the ventricles and the arteries into which the ventricles pump their blood
- between left ventricle and aorta: aortic valve
- between right ventricle and pulmonary trunk: pulmonary valve
42
what are valves made of
fibrous tissue (collagen) and covered by endothelium
43
what are valve rings made of
cartilage
what the valves attach to
44
chordae tendineae
tough, thin fibrous cords of tendinous-type tissue that AV valve leaflets are attached to
extend from the leaflets and attach to papillary muscles
45
papillary muscles
cone shaped muscles that protrude from the inner surface of the ventricular walls
- pulls the chordae tendineae to keep the valve closed
46
cardiac skeleton
the fibrous skeleton of the heart made of dense connective tissue
47
cardia skeleton functions
physically separates the atria from the ventricles
electrically inactive and blocks the direct spread of electrical impulses from the atria to the ventricles
provides support for the heart, providing a point of attachment for the valves leaflets and cardiac muscle
48
coronary circulation
part of the systemic circulatory system and supplies blood to and provides drainage from the tissues of the heart
49
coronary arteries
arteries supplying the heart
50
cardiac veins
collect poorly oxygenated blood and empty into the coronary sinus, which returns the blood to the right atrium
51
coronary sinus
a collection of veins joined together to form a large vessel that collects blood from the myocardium of the heart and empties into the right atrium, returning the poorly oxygenated blood back to the right side of the heart
52
systole
represents the time during which the left and right ventricles contract and eject blood into their respective artery
53
diastole
represents the period of time when the ventricles are not contracting; relaxed
54
atherosclerosis
a condition in which the arteries become hardened and narrowed because of an excessive accumulation of plaque in the vessel wall
atherosclerotic plaque made of fat, cholesterol, calcium and other substances in the blood
55
angina
chest pain; when a plaque is present in a coronary artery, restricted blood flow to the heart muscle may result in chest pain
56
myocardial infraction
heart attack
atherosclerotic plaques can grow so large that they completely block arterial blood flow; heart muscle dies due to loss of blood supply
57
syncytium
a set of cell that act together
58
intercalated discs
join cardia muscle cells (myocytes) together, contain gap junctions and desmosomes
mechanically, chemically, and electrically connect myocytes to one another
59
autorhythmicity/automaticity
the heart contract or beats rhythmically as a result of action potentials that it generates itself
60
myogenic
muscular in origin, action potentials in the heart generated without nervous or hormonal stimulation
61
2 types of specialized cardia muscle cells
contractile cells
conducting cells
62
contractile cells
perform the mechanical work of pumping or contracting to propel blood forward
~99% of myocytes
contract when stimulated by an action potential
63
conducting cells
autorhythmic cells which initiate and conduct action potentials which are responsible for contraction of the contractile cells
~1% of myocytes
are in electrical contact with each other and the cardiac contractile cells through the gap junctions
64
where are conducting myocytes found
- sinoatrial node (SAN) - wall of the right atrium
- internodal pathways - SAN to AVN and also cross the interatrial septum to the left atrium
- atrioventricular node (AVN) - base of the right atrium
- the bundle of His (AV bundle) - cardiac skeleton
- the left and right bundle branches - along the interventricular septum
- purkinje fibers - myocardium of the ventricles
65
electrical connection between atria and ventircles
AVN and bundle of His
66
where are action potentials generated that drive the rest of the conducting system
SAN (sinoatrial node)
67
cardiac pacemaker
initiates action potentials that set the heart rate
68
pathway of action potentials generated by SAN
SAN generates action potentials -> internodal pathways -> contractile cells of both the left and right atria -> left and right atria contract at the same time -> stimulus is passed by the internodal pathways to AVN -> wave of depolarization must pass through ACN and Bundle of His to excite ventricles due to presences of cardiac skeleton
69
why is there an AVN delay
ensure the atria depolarize and contract before the ventricles depolarize and contract
70
purkinje fibers
large number, diffuse distribution of action potential, fast conduction and velocity
action potential from left and right bundle branches that travel along intraventricular septum
71
wolff-parkinson-white syndrome
there is an extra connection in the heart called an accessory pathway - an abnormal piece of muscle that connects directly between the atria and ventricles allowing electrical signals to bypass the AVN and move to the ventricles fast than usual, leading to an abnormally fast heartbeat
72
fast action potentials
found in contractile myocytes in the atrial myocardium, ventricular myocardium, bundle of His, bundle branches, and purkinje fibers
73
slow action potentials
found in conducting myocytes in the sinoatrial node and atrioventricular node
74
what ions are involved in the phases of cardiac action potentials, which direction is flow
Na, K, Ca
Kin > Kout
Caout > Cain
Naout > Nain
75
what does the pacemaker potential allow for
allows the SAN cells to generate regular spontaneous action potentials without any external influence from nerves or hormones
76
3 ionic conductances involved in slow action potentials
1. progressive reduction in K permeability (K channels close)
2. F-type channels (depolarizing Na current, Na moves into cell)
3. t-type channels (Ca channel, T = transient (opens only briefly) Ca moves into cell to provide final depolarization to bring membrane to threshold)
77
l-type channels
Ca channel, L=longlasting, channels open mores slowly and remain open for a prolonged period depolarizing phase
78
repolarization phase of slow action potential
opening of voltage gated K channels, K leaves the cell
79
what is responsible for the depolarization in a slow action potential
Ca
80
where are fast type action potentials found
atrial contractile cells (atrial myocardium)
81
electrocardiogram (ECG, EKG)
a recording of the electrical activity of the heart
a measure of the currents generated in the ecf by the changes occuring simultaneously in many cardiac cells
82
P wave
first wave on ECG
represents depolarization of the atria
upward deflection in the trace
approx 25 ms after the P wave the atria will contract
83
QRS complex
wave consisting of 3 peaks
represents depolarization of the ventricles
84
T wave
upward deflection
represents repolarization of the ventricles
85
AVN block
a type of heart block in which conduction between the atria and ventricles is impaired; partial or complete interruption of the impulse from the atria to the ventricles
86
partial AVN block
the damaged AVN permits only every other atrial impulse to be transmitted to the ventricles; every second p wave is not followed by a qrs complex or t wave
87
complete AVN block
electrical depolarizations of the atria are not transmitted to the ventricles; no synchrony between atrial and ventricular electrical activities
88
sarcolemma
plasma or cell membrane of a cardiac
89
sarcoplasmic reticulum
a special type of smooth endoplasmic reticulum which stores and pumps Ca (important for excitation-contraction coupling)
90
sarcomeres
contractile unit of muscle; contain the protein filaments actin and myosin
91
what are myofibrils made of
sarcomeres
92
actin
thin filament
93
myosin
thick filament
94
t-tubules
invaginations of the sarcolemma; surround myofibrils; transmit action potentials propagating along the surface membrane to the interior of the muscle fiber; lie in close proximity to the sarcoplasmic reticulum and contain many l-type ca channels
95
excitation-contraction coupling
the process by which the arrival of an action potential at the cell membrane leads to contraction of the muscle cell
96
steps of ECC
- Ca levels control contraction of the cardiac muscle
- during the plateau of the action potential, extracellular Ca enter the cytoplasm of the cardiac muscle cell through l-type Ca channels
- Ca binds to ryanodine receptors on the sarcoplasmic reticulum
- ryanodine receptor opens Ca channel, releasing Ca from SR
= calcium-dependent calcium release
97
troponin
contains binding sites for Ca and tropomyosin
regulates access to myosin-binding sites on actin
98
tropomysoin
partially cover the myosin binding sites on actin at rest, preventing cross bridges from making contact with actin
99
steps invloved in contraction
- excitation spreads along sarcolemma from ventricular myocyte to ventricular myocyte by t-tubules
- excitation spreads down to the interior of the myocyte by t-tubules
- during plateau phase of fast action potential, permeability of myocyte to Ca increases a l-type Ca channels open
- ryanodine receptors open more Ca channels
- cytosolic Ca binds to troponin, inducing a conformational change in the regulatory complex
- binding sites on actin are now able to bind to the energized cross-bridge on the mysoin head
100
how does contraction end
with the removal of Ca from troponin
101
how is Ca removed
- l-type channels close
- SR no longer stimulated to release Ca
- SR contain Ca-ATPases to pump Ca in the cytosol back into the SR
- Ca also removed from the myocyte by Na/Ca exchanger found in sarcolemma
- the reduced binding of Ca to troponin will block the sites of interaction between mysoin and actin, allowing for relaxation of the myofibrils
102
isovolumetic contraction
ventricles, contract, all heart valves closes (AV and semilunar valves) blood volume in ventricles remains constant, pressure rises; muscles develops tension but cannot shorten
103
ventricular ejection phase
pressure generated by the ventricles during contraction now exceeds the pressure in the artery into which the ventricle ejects its blood
104
isovolumetric ventricular relaxation
all heart valves close, blood volume remains constant, pressure drops
105
ventricular filling
AV valves open, blood flows into ventricles from atria
106
passive ventiruclar filling
the ventricles receive approx 70% of their blood volume
- atria and ventricles are relaxed
107
atrial contraction/atrial kick
completes ventricular filling
ventricles still relaxed
108
end-diastolic volume (EDV)
the amount or volume of blood in each ventricle at the end of ventricular diastole
109
end-systolic volume (ESV)
the amount or volume of blood in each ventricle at the end of ventricular systole, or at the end of ventricular contraction and ejection
110
stroke volume equation
SV = EDV - ESV
~70-75mL
111
wigger's diagram
shows the pressure and volume changes for the heart
112
first heart sound
lub
caused by closure of the AV valves at the beginning of isovolumetric ventricular contraction and signifies the onset of ventricular systole
113
second heart sound
dub
cause by closure of the semilunar valves and signifies the onset of ventricular diastole
114
laminar flow
characterized by smooth concentric layers of blood moving parallel down the length of a blood vessel
115
stenotic valve
a valve in which the leaflets do not open completely, this can occur when the valve leaflets become stiffer due to calcium deposits or scaring of the valve
when blood flows through a stenotic valve, it becomes turbulent and is heard as a murmur
116
insufficient valve
does not close completely die to widening of the aorta or scaring of the valve
blood flows backwards through the leaky valve and produces turbulence heard as a murmur
117
sympathetic postganglionic fibers innervate
the entire heart
norepinehprine released
118
parasympathetic postganglionic fibers innervate
atria, SAN and AVN
acetylcholine released
119
parasympathetic stimulation decreases ...
- heart rate by decreasing rate of depolarization or the rate of rise to threshold of the pacemaker potential
- the conduction of the electrical impulses through the AVN, increasing AVN delay
- contractility of the atrial myocardium, decreasing the force of contraction
120
sympathetic stimulation increases...
- heart rate by increasing rate of depolarization, or the rate of rise, of the pacemaker potential to threshold
- conduction of the electrical impulses through the AVN decreasing AVN delay
- contractility of the atrial and ventricular myocardium, increasing the force of contraction
121
cardiac output equation
CO = HR x SV
122
how do we alter heart rate
by modifying the activity of the SAN (heart's pacemaker)
123
how do we alter stroke volume
by varying the strength of the contraction of the ventricular myocardium
124
to increase heart rate, what must be released
increase sympathetic activity and increase release of epinephrine from the adrenal medulla to stimulate/increase the activity of the SAN increasing HR and CO
125
to decrease heart rate, what must be increased
increase parasympathetic activity, decreases SAN
126
sympathetic stimulation increases permeability of
f-type channels - allow Na to enter the cell
t-type channels - allow Ca to enter the cell
127
parasympathetic stimulation decreases the slope of the pacemaker by
decrease f-type channel permeability - reducing movement of Na into cell
increasing K channel permeability - causing more K to leave the cell
128
3 factors affecting stroke volume
- the end diastolic volume (EDV); preload
- the contractility of the ventricular myocardium
- the afterload
129
how are the ventricles stretched
increased stretch when ventricles are fuller with blood
130
frank-starling mechanism
the relationship between the end diastolic volume and stroke volume
- intrinsic mechanism
131
preload
the tension or load on the ventricular myocardium before it begins to contract, or the amount of filling of the ventricles at the end of diastole (EDV)
132
why does the parasympathetic system not affect the venous volume
most of the blood vessels in our body receive only sympathetic innervation to their smooth muscle
133
contractility
the strength of contraction at any given EDV
134
ejection fraction equation
ejection fraction = SV/EDV
135
afterload
the tension against which the ventricle must eject its blood; it is closely related to the arterial pressure
- the greater the afterload, the longer the period of isovolumetric contraction during which time the heart generates sufficient pressure to open the valves and eject blood, and a smaller stroke volume
136
what affects afteload
any factor that restricts blood flow through the arterial system
- arterial blood pressure, vascular resistance, stenotic valve
137
endothelial cells
form a physical lining the blood cells do not normally adhere to in the heart and in the blood vessels, lines the entire circulatory system
138
vasoconstriction
contraction of arterial smooth muscle decreases the diameter of the artery
139
vasodilation
relaxation of arterial smooth muscle increases the diameter of the artery
140
elastic arteries
contain many elastic fibers and few smooth muscle cells
- pulmonary trunk and aorta
can tolerate pressure changes during the cardiac cycle
141
muscle arteries
contain many smooth muscle cells and few elastic fibers
- most of the vessels in the arterial system
function to distribute blood throughout the body
142
arterioles
smallest of the arteries
composed of 1 to 2 layers of smooth muscle cells; resistance vessels in the body
play a very important role in determining our mean arterial pressure (blood pressure)
- regulate blood flow to organs by regulating the amount of blood flow to capillary beds
143
walls of arterioles have an abundance of
circular smooth muscle that forms rings around the arterioles
allows the state of constriction of the arteriolar smooth muscle to be regulated
144
tone
partial contraction in the absence of external factors such as neural or hormonal stimuli
145
factors that affect intrinsic/basal tone
extrinsic: MAP
intrinsic:
146
extrinsic factors affecting blood flow
- sympathetic nerve fibers release norepinephrine to cause vasoconstriction
- sympathetic tone
- sympathetic innervation to the arteriolar smooth muscle to regulate MAP
- noncholinergic, noradrenergic neurons (NO - a vasodilator)
- epinephrine - vasoconstriction or vasodilation
147
active hyperemia
local control which acts to increase blood flow when the metabolic activity of an organ or tissue increases
148
hyperemia
an excess of blood in the vessels supplying an organ or tissue
149
flow autoregulation
locally mediated changes in arteriolar resistance occurring when a tissue or organ experiences a change in its blood supply resulting from a change in blood pressure
150
myogenic response
the direct response of arteriolar smooth muscle to stretch
- an increase in arterial pressure and blood flow causes arterial walls to stretch, in addition to changing levels of local chemical factors
151
reactive hyperemia
locally controlled form of flow autoregulation
- occurs at constant metabolic rate
- occurs due to changes in the concs of local chemicals
152
capillaries
thin walled vessels one endothelial cell thick
contains no smooth muscle or elastic fibers
function in the rapid exchange of material between the blood and the interstitial fluid
153
intercellular clefts
gaps between capillaries that act as channels or water-filled spaces between endothelial cells through which small water-soluble substances can pass through
154
3 types of capillaries
continuous capillary
fenestrated capillary
sinusoidal capillary
155
continuous cappilary
uninterrupted/complete endothelium and continuous basement membrane
- have the lowest permeability of all capillary types allowing the exchange of water, small solutes, and lipid-soluble material only
156
pericytes
lie external to the endothelium
may help stabilize the walls of blood vessels and help regulate blood flow through capillaries
157
fenestrated capillaries
have numerous fenestra/pores (membrane lined cylindrical conduits that run completely through the endothelial cell, from the capillary lumen to the interstitial space)
surrounded by an intact or complete basement membrane
fenestra/pores allow rapid exchange of water and solutes, including larger solutes such as small peptides
found in tissues where capillaries are highly permeable (endocrine organs, choroid plexus, GI tract, kidneys)
158
sinusoids (sinusodial capillaries)
large diameter, flattened and irregularly shaped have large fenestrae and large gaps between adjacent endothelial cells
basement membrane very thin or absent
allows free exchange of water and solutes, including large substances such as rbc, cell debris, plasma proteins
found in liver, bone marrow, spleen
159
microcirculation
the circulation of blood through the smallest vessels in the body
- arterioles, metarterioles, capillaries, venules, veins
160
precapillary sphincters
ring of smooth muscle which guards the entrance to the capillary
- contract and relax in response to local condition to alter the flow of blood in the capillary beds
- receive no innervation
161
metaarterioles
aka precapillary arterioles
small blood vessels arising from an arteriole, pass through a capillary network and empty into a venule
contain smooth muscle cells enabling them to regulate blood flow by changing diameter
162
transcytosis
a process involving vesicles in which endothelial cells pick up material on one side of the plasma membrane by pinocytosis or receptor-mediated endocytosis, transport the vesicles across the cell, and discharge the material on the other side by exocytosis
163
bulk flow
the movement of protein-free plasma across the capillary wall
- quantity of solutes moving is small compared to transfer by diffusion
function to distribute ecf volume
164
filtration
movement of protein-free plasma by bulk flow from the capillary plasma to the interstitial fluid through water-filled channels
165
reabsorption
movement of protein-free plasma by bulk flow from the interstitial fluid to the capillary plasma
166
bulk flow is driven by
hydrostatic and colloid osmotic pressure between the capillary plasma and the interstitial fluid
167
hydrostatic pressure
the force of a fluid against a membrane
168
colloid osmotic pressure
the osmotic pressure due to the presence of impermeable proteins
- difference in protein conc btw the plasma and the interstitial fluid creates an osmotic force; the proteins draw fluid towards them, into the compartment that they occupy
169
blood colloid osmotic pressure
the osmotic pressure due to the presence of a large number of non-permeating plasma proteins such as albumin within the blood; proteins pull blood into the capillaries
170
net pressure
the sum of the outward pressure and the inward pressures
171
outward pressures
capillary hydrostatic pressure and the interstitial fluid osmotic pressure
172
inward pressure
the osmotic force due to the plasma protein conc and the interstitial fluid hydrostatic pressure
173
at the arterial end of the capillary
hydrostatic pressure ~35mmHg
- pushes fluid out of the capillary
blood colloid osmotic pressure ~28mmHg
- draws fluid into the capillary
-interstitial fluid hydrostatic press ~0mmHg
- does not cause movement of fluid
interstitial fluid colloid osmotic pressure ~3mmHg
- causes fluid to move out of the capillary
--net pressure = 35+3-0-28 = 10mmHg
- positive number therefore favors filtration of fluid from the capillary into the interstitial fluid
174
venous end of the capillary
capillary hydrostatic pressure ~15mmHg
- pushes fluid of of the capillary
blood colloid osmotic pressure ~28mmHg
- draws fluid into the capillary
interstitial hydrostatic pressure ~0mmHg
- no movement
interstitial fluid colloid osmotic pressure ~3mmHg
- causes fluid to move out of the capillary
--net pressure = 15+3-0-28 = -10mmHg
- negative number therefore favors absorption of fluid from the interstitial fluid into the capillary
175
starling forces
four factors that determine net filtration pressure
- hydrostatic pressure
- blood colloid osmotic pressure
- interstitial hydrostatic pressure
- interstitial fluid colloid osmotic pressure
176
is more fluid filtered or absorbed
filtered
177
veins
expand and recoil passively with changes in pressure
high capacitance vessels as can store large amounts of blood
highly distensible, expanding easily at low pressure and have little elastic recoil
reservoir for blood
178
venous valves
composed of two leaflets or folds; prevents backflow of blood into the capillaries
- aid in returning blood to the heart and ensuring blood flows in one direction
179
varicose veins
occur when the walls of the veins near the valves become weakened or stretched and the valves do not work properly; blood pools in the veins and vessels become distended
180
mechanisms for venous return
- smooth muscle in veins - innervated by sympathetic neurons which cause contraction
- skeletal muscle pump - compress veins
- respiratory pump - inspiration causes an increase in venous return
181
relationship between venous return and frank-starling law
inc EDV -> inc cardiac fiber length -> inc force during contraction -> inc SV
182
lymphatic system
consists of small organs (lymph nodes) and tubes (lymphatic vessels) through which lymph flows
183
lymphatic capillaries
made of single layer of endothelial cells resting on a basement membrane
have large water filled channels that are permeable to all interstitial fluid components, including proteins - through bulk flow
closed ended
184
lymph role
defense and part of the immune response
goes into right atrium
185
mechanisms that contribute to flow of lymph
- smooth muscle
- one way valves
- skeletal muscle contractions
- respiratory pump
186
compliance
ability of a vessel to distend and increase volume with increasing transmural pressure, which is the pressure inside the vessel minus the pressure outside the vessel
- the greater the compliance of a vessel, the more easily it can be stretched
187
pulse pressure equation
pp = sp-dp
188
hypertension
chronically increased arterial blood pressure
189
hypotension
abnormally low arterial blood pressure
190
normal blood pressure
120/80mmHg
191
mean arterial pressure equation
MAP = CO x TPR
192
total peripheral resistance
combined resistance to flow of all the systemic blood vessels
193
short-term regulation of MAP
- seconds to hours
- baroreceptors reflexes modify the activity of autonomic nerves supplying the heart and blood vessels as well as changes in the secretion of hormones
- adjusts co and tpr by ans
194
long-term regulation of MAP
- adjust blood volume
- restore normal salt and water balance through mechanisms that regulate urine output and thirst
195
arterial baroreceptors
mechanoreceptors that detect changes in your blood pressure
- respond to changes in pressure when the walls of the vessel stretch and relax
- generate action potentials
-- inc in MAP will inc ap
-- dec in MAP will dec ap
196
medullary cardiovascular center
located in the medulla oblongata in the brainstem
receive input from the baroreceptors which determines frequency of ap to alter parasympathetic or sympathetic innervation
197
chemoreceptors
regulate respiratory activity
