KIN 226 > Cardiovascular Regulation > Flashcards

Cardiovascular Regulation Flashcards

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1
Q

Regulation of Heart Rate

A

– Heart maintains its own rhythm
– Sinoatrial node (SA node)- stimulus for heart action-
the “pacemaker”
– SA node signal sent to both atria and to
Atrioventricular node (AV node)
* 0.10 sec delay to allow blood to pass from atria into
ventricles below

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2
Q

Regulation of cardiovascular system

A

-AV node gives rise to the AV bundle (Bundle of His)
- transmits signal via Purkinje fibers (very fast
impulses, 0.06 sec) to ventricles for contraction
* Transmission of cardiac impulse:
SA node → Atria → AV node → AV bundle → Ventricles

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3
Q

what does SA and AV node do in the heart

A

SA node generates impulse
AV node conducts impulse to
ventricular mass

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4
Q

regulation of the cardiovascular system
cardiovascular control center:

A

-located in the medulla in the brainstem
egulates:
– heart’s output (SA and AV Node input)
– distribution of blood in the body (viscera, muscle,
etc.)
– vasomotor tone in active muscle (vasoconstriction,
vasodilation)

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5
Q

autonomic nervous system

A

parasympathetic and sympathetic

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6
Q

sympathetic

A

Catecholamine
release (epinephrine
& norepinephrine)
* Leads to tachycardia
(HR > 100 bpm)

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7
Q

parasympathetic

A

Acetylcholine release
* Leads to bradycardia
(HR < 60 bpm)
rest and digest
athletes (endurance) will typically be more bradycardic

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8
Q

sympathetic nervous system

A

-increase vasoconstriction
-increase vasodilation
-increase contractility (inotropic effect)
-increase heart rate (chronotropic effect)

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9
Q

parasympathetic nervous system

A

-decrease heart rate
-decrease contractility
-decrease vasodilation of the arterioles of skeletal muscle
-decrease vasoconstriction of visceral arterioles

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10
Q

what nervous system is stimulated when we exercise and what is inhibited?

A

stimulated =sympathetic inhibited= parasympathetic

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11
Q

resting membrane potential (RMP) of skeletal muscle =

A

more negative on inside,
more positive on outside

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12
Q

depolarization

A

membrane potential becoming more positive (influx of sodium)
* Action potential = contraction
systole
contraction

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13
Q

repolarization

A

membrane potential becoming more negative, back towards resting (efflux of potassium)
relaxation (diastole)

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14
Q

ECG

A

measures of the hearts electrical activity detected as voltage changes with the ECG

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15
Q

ECG P wave

A

atrial depolarization

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16
Q

ECG QRS complex

A

ventricle depolarization (systole)
-often masks atrial repolarization

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17
Q

ECG T wave

A

ventricle repolarization (diastole)

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18
Q

why is QRS such a big electrical change

A

the ventricles are much bigger so there needs to be much more electrical activity
what is it - ventricular depolarization not atrial

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19
Q

which electrical activity represents a persons pulse

A
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20
Q

calculating HR via ECG strip
step 1

A

calculate distance the paper travels in 1 minute. (paper speed is 25mm/second)

so in one minute the paper traveled 1500mm/min (25mm 60sec/min)

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21
Q

calculating HR via ECG strip
step 2

A

measure the distance between 4 cycles
one box =5mm,
4 cycles = = boxes mm

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22
Q

blood volume

A

blood volume in blood vessels is normally 5L
-fully dilated, vessels could hold 20L

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23
Q

arterioles are surrounded by smooth muscle

A

-innervated by sympathetic neurons, which cause vasoconstriction or vasodilation

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24
Q

blood flow : vasoconstriction and vasodilation

A

central control (VC and VD)
-peripheral control (metabolic by-products cause VD)
-nitric oxide

autoregualtory mechanism detect metabolic by products reflecting elevated metabolism and the need for more O2

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25
Nitric oxide
-is a natural by product -can also be taken dilates the blood vessel will increase blood flow
26
distribution of blood flow
-dependent on immediate needs of specific tissue -at rest, blood goes to metabolically active tissue such as brain, heart, kidney and liver -redistribution of blood is critical to the body -mechanism is by changing vessel diameter (vasoconstriction/vasodilation)
27
why may you not want to have a large meal prior to intense exercise ?
the food cannot be digested die to the fact that blood flow will got to the muscles that are being worked. but the body still wants to get rid of the food
28
the cardiovascular system
pump- heart transportation - vessels medium - blood
29
blood id for transport
O2 from lungs to cells CO2 cells to lungs nutrients form digestive organs to cells waste products in the cells to kidneys, lungs, liver hormones form endocrine glands to cells enzymes to cells
30
blood regulates
pH through buffer -blood is typically quite basic (pH 6.9-7.5) Body temp -coolant properties of water content (about 50% of blood is water)
31
blood is a protector blood loss/fluid loss clotting mechanism- vitamin essential for clotting
vitamin k
32
alcohol has a negative affect on this vitamin function
vitamin b
33
what is blood made of? two portions
1. formed elements (blood cells 45% of blood volume) = hematocrit (mostly red blood cells) -erythrocytes (red blood cells) -leucocytes (white blood cells) -thrombocytes (platelets) 2. plasma (liquid containing dissolved substances; 55% of blood volume)
34
55% plasma what is in it
90% H2O 7% plasma proteins 3% other
35
45% formed elements (hematocrit) what is in it
99% red blood cells less than one percent white blood cells and platelets
36
plasma proteins 7%
albumins 55% globulins 38% fibrinogen 7%
37
albumins (55% of the plasma proteins)
-transport fatty acids, hormones -smallest protein
38
globulins (38% of plasma proteins)
-include immunoglobins (antibodies) -transport protein, bind with ions, hormones and other compounds
39
fibrinogen 7% of plasma proteins
-participates in clotting -forms fibrin -largest protein
40
plasma - other solutes (3%)
-non protein nitrogen (NPN) substances -foods (CHO, pro, fats) -regulatory substances (hormonal) -respiratory gases (O2 and CO2 ) -electrolytes (sodium, potassium, ect)
41
erythrocytes: RBCs
-produced in bone marrow -biconcave disc-no nucleus or mitochondria -red colour due to hemoglobin -life 120 days -amino acids and iron recycled what you have in your diet affects your ability to produce RBCs
42
red blood cells
transport oxygen bound to hemoglobin (Hb) -heme contains iron which binds O2 -as much as 20 ml O2 cna be bound in 100 ml of blood
43
hemoglobin (Hb)
protein portion of a RBC that binds oxygen, consists of 4 iron containing pigments (hemes) and a globin protein
44
sex difference regarding RBC and Hb
Avg. male carries 10-15% more Hb than avg. female (6% more RBCs) -testosterone stimulates red blood cell production
45
anemia
low RBC, low HB (low iron) therefor reduced carrying capacity of O2=fatigue -more prelevent in females
46
oxygen transport and cardiac output
at rest -100ml blood carries 20ml O2
47
if 100ml of blood carries 20 ml O2 how much O2 does the average person carry ?
total blood volume is 5L therefor 5000ml/100ml = 50 50 x 20ml = 1000ml O2
48
blood viscosity (hematocrit)
the percent of total blood volume composed of blood cells (40-45%) formed elements males : 40-54% females: 38-47% HCT= 60% or more is dangerous (thick blood, flow is reduced-more resistance) reasons why: -dehydration -blood doping
49
blood doping in sport in which sport is it most prevalent ?
cycling
50
blood doping: a non-pharmalogical approach to enhancing performance
red blood cell re-infusion - blood doping how it works -withdrawal of 1-4 units of blood -RBCs are frozen -re-infusion 1-7 days prior to competition effects -increases RBC number -increase oxygen carrying capacity -increases ability to perform endurance during exercise have more viscous blood
51
practice application causes of increases hematocrit
acute exercise effect -due to less plasma, fluid shifts, sweating dehydration -due to less plasma, sweating blood doping/EPO -due to increased RBCs
52
practice application dangers of increase hematocrit?
increases viscosity (thickness) - all causes -increase Tor, increased BP decreased plasma volume - dehydration -decreased SV, decreased q, increased HP and BP to maintain in general -excess stress to the cardiovascular system -ultimately if serious enough, cardiac events and death
53
hormonal blood boosting erythropoietin (EPO)
hormone produced by the kidneys
54
hormonal blood boosting epoetin (exogenous EPO)
-synthetic version -may increase RBC number by 12% - unconventional or non medical administration may create significantly greater increase -increased risk of stroke, heart attack, hart failure, pulmonary edema
55
other means to enhance oxygen transport new substance classes and potentially lethal side effect s
-perfluorocarbon emulsions -bovine and human hemoglobin solutions -increased systemic and pulmonary blood pressure -renal toxicity -impaired immune function
56
blood donation
-removal of 500ml: 8-10% of total volume form 500ml of total blood volume -fluid replacement will return plasma volume to normal within 24-48 hours -takes 6 weeks to replenish red blood cells
57
cardiovascular dynamic central vs. peripheral circulatory responses
total peripheral resistance: factors that oppose blood flow (vessel length, vessel diameter, viscosity) increase length = increase resistance increase diameter = decreased resistance increase velocity = increase resistance
58
TRP=
MAP / Q
59
VO2 max maximal oxygen consumption
-greatest amount of oxygen that the body can take in, transport, and utilize during exercise -expressed in L/min (absolute) or in ml/kg/min (relative) use this one
60
VO2 max formulas
VO2max = Q max. x A-VO2 diff max VO2max= SV x HR x A-VO2 diff max
61
Limits to VO2 mx respiratory system
O2 diffusion, ventilation , a-vO2 diff
62
Limits to VO2 mx cardiovascular system
-central factors: Q= SV x HR, arterial blood flow, Hb concentration peripheral: blood flow to non-exercising regions, muscle blood flow, capillary density, O2 extraction and exchange
63
limits to VO2 max muscle/metabolism
-myoglobin, enzymes, energy stores and delivery -mitochondrial size and number ( would not be as fatigued)
63
limits to VO2 max delivery of oxygen (biggest factor outside of genetics)
not utilization, is believed to be the main limiting factor ability of the heart Q Value
64
limits to VO2 max geentics (25-40%)
may explain individual differences in training adaptations
65
where within the CNS is the cardiovascular control centre located
medulla
66
what are the three main purposes of blood
protect, regulate, transport
67
what two elements is blood divided into
hematocrit, plasma
68
what is the primary factor that limits VO2max
delivery of oxygen Q- cardiac output
69
KIN 226
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