Midterm 2: Chapters 6 and 8 Flashcards
the cardiovascular system: what are the major functions?
- delivers o2, nutrients
- removes co2, other wastes
- transports hormones, other molecules
- temperature balance and fluid regulation
- acid-base balance
- immune function
the cardiovascular system: what are the three major circulatory elements?
- a pump (heart)
- channels or tubes (blood vessels)
- a fluid medium (blood)
_____ grenerates pressure to drive blood through vessels.
heart
_____ must meet metabolic demands.
blood flow
how does the blood flow through the heart?
from superior/inferior vena cavae -> RA -> tricuspid valve -> RV -> pulmonary valve -> pulmonary arteries -> lungs -> pulmonary veins -> LA -> mitral valve -> LV -> aortic valve -> aorta
right side of the heart is the ?
pulmonary circulation
pumps deoxygenated blood from body to lungs
left side of the heart is the?
systemic circulation
pumps oxygenated blood from lungs to body
myocardium itself needs blood and blood comes from?
- right coronary artery supplies right side of heart
- left (main) coronary artery supplies left side of heart
whenever you refer to myocardium you are referring to the ?
heart
myocardium: _____ muscle
cardiac
what are some left ventricle (LV) characteristics?
- must pump blood to entire body
- thickest walls (hypertrophy)
- LV hypertrophies with exercise and with disease
- but exercise adaptations versus disease adaptations very different
skeletal muscle cells are?
- large, long, unbranched, multinucleated
- intermittent, voluntary contractions
- Ca2 released from SR
myocardial cells are?
- small, short, branched, one nucleus
- continuous, involuntary rhythmic contractions
- calcium-induced calcium release
myocardial cells have one one fiber type similar to type I of skeletal muscle that include?
- high capillary density
- high number of mitochondria
- striated
cardiac muscle fibers connected by regions called?
intercalated discs
_____: hold cells together.
desmosomes
____: rapidly conduct action potentials
gap junctions
what are the two main pathways of the heart?
intrinsic and extrinsic
intrinsic control of heart activity means the heart controls its self, this is also known as?
spontaneous rhythmicity
_____: special heart cells generate and spread electrical signal.
spontaneous rhythmicity
what are the electrical signals that the spontaneous rhythmicity spread?
- sinoatrial (SA) node
- atrioventricular (AV) node
- AV bundle (bundle of His)
- purkinje fibers
extrinsic control of heart activity consists of?
parasympathetic and sympathetic control
heart activity that is parasympathetic controls?
- decreases force of contraction
- decreased HR below intrinsic HR
( intrinsic HR: 100 beats/min, normal resting HR (RHR): 60 to 100 beats/min, elite endurance athlete: 35 beats/min)
heart activity that is sympathetic controls?
- increases force of contraction
- increases HR above intrinsic HR
- determines HR during physical, emotional stress
- maximum possible HR: 250 beats/min
what is the cardiac cycle?
all mechanical and electrical events that occur during one heartbeat
the cardiac cycle consists of?
diastole and systole
_____: relaxation phase
- chambers fill with blood
- twice as long as systole
diastole
_____: contraction phase
systole
during the cardiac cycle ventricular systole is 1/3 of the cardiac cycle time and what else is occurring?
- blood ejected
- during systole, blood ejected out, but some leftover
- blood leftover in ventricle = end-systolic volume (ESV)
during the cardiac cycle ventricular diastole is 2/3 of the cardiac cycle time and what else is occurring?
- fill 70% passively, remaining 30% by atrial contraction
- at end, blood in ventricle = end-diastolic volume (EDV)
_____: volume of blood pumped in one heartbeat
stroke volume (SV)
ejection fraction (EF): ?
% of EDV that was SV
- SV / EDV = EF
- 60 mL / 100 mL = .6 = 60%
(normal for healthy, active young adult at rest)
- clinical index of heart contractile function
_____: total volume of blood pumped per minute
- Q = HR * SV (use L/min)
- resting cardiac output (4.2 to 5.6 L/min)
(average total blood volume: 5 L, therefore, total blood volume circulate once every min)
cardiac output
what is involved in the vascular system?
arteries, arterioles, capillaries, venues, veins
_____: carry blood away fro heart.
arteries
____: control blood flow, and waste exchange
arterioles
____: site of nutrient and waste exchange
capillaries
____: collect blood from capillaries
venules
_____: carry blood from venues back to heart
veins
_____: pressure exerted by blood on arterial walls.
blood pressure (BP)
_____:
- highest pressure in artery (during systole)
- top number, ~ 110 to 120 mmHG
systolic pressure (SBP)
_____:
- lowest pressure in artery (during diastole)
- bottom number, ~70 to 80 mmHg
diastolic pressure (DBP)
_____:
- average pressure over entire cardiac cycle
mean arterial pressure (MAP)
what are the general hemodynamics?
blood flow, pressure, resistance
_____: required by all tissues
- ? = change in pressure / resistance
blood flow
_____: force that drives flow
- provided by heart contraction
pressure
_____: force that opposes flow
- provided by physical properties of vessels
resistance (R)
_____: the constriction of blood vessels, which increases blood pressure.
vasoconstriction (VC)
_____: the dilatation of blood vessels, which decreases blood pressure.
vasodilation (VD)
_____: also known as resistance vessels
- control systemic R
- site of most potent VC and VD
arterioles
what is the distribution of blood?
blood flows to where it is needed the most
regions of _____ metabolism lead to ______ blood flow
increased; increased
according to intrinsic control of blood flow arterial walls can respond to?
local control mechanisms
_____: ability of local tissues to constrict or dilate arterioles that serve them
intrinsic control
what are the three types of intrinsic controls?
- metabolic mechanisms (VD)
- endothelial mechanisms (mostly VD)
- myogenic mechanisms (VC, VD)
_____:
- strongest stimulus for release of local VD chemicals
- buildup of local metabolic by-products ( decreased O2, increased CO2, K+, H+, lactic acid)
metabolic mechanisms (VD)
_____:
- substances secreted by vascular endothelium (arterial inner lining)
- endothelium-mediated vasodilation
endothelial mechanisms (mostly VD)
_____:
- local pressure changes can cause VC, VD
- decreased pressure causes VD
- increased causes VC
myogenic mechanisms
_____: redistribution of flow by the nervous system
extrinsic neural control
what happens in the extrinsic neural control of blood flow?
sympathetic nervous system innervates smooth muscle in arteries and arterioles
the baseline of sympathetic activity leads to?
vasomotor tone to maintain adequate blood supply
_____ sympathetic activity leads to ____ VS of area. (blood flow to that area decreases)
increased; increased
_____ sympathetic activity leads to ____ VC; passive VD (blood flow to that area increases)
decreased; decreased
what is the distribution of Venous Blood?
venous reservoir can be liberated, sent back to heart and into arteries
at rest, veins contain 2/3 blood volume which means?
- high capacity to hold blood volume (capacitance vessels)
- elastic, balloon like vessel walls
- much less vascular smooth muscle
- serve as blood reservoir
what mechanisms assist venous return?
muscle pump and one-way venous valves
integrative control of blood pressure is when?
blood pressure maintained by autonomic reflexes
_____:
- sensitive to changes in arterial pressure
- afferent signals from ? to brain
- efferent signals from brain to heart and vessels
- adjust HR and arterial pressure back to normal
baroreceptors
what are the three major functions of blood?
- transportation (O2, nutrients, waste)
- temperature regulation
- buffers acids from anaerobic metabolism pH balance
what is the blood volume in men and women?
- 5 to 6 L in men
- 4 to 5 L in women
? = plasma + formed elements
whole blood
_____: (55 - 60% blood volume)
- can decrease by 10% w/ dehydration in the heat
- can increase by 10% w/ training, heat acclimation
plasma
_____: (40-45% of blood volume)
- % of volume composed of formed elements
- erythrocytes (red blood cells): 99%
- leukocytes (white blood cells): <1%
- platelets: <1%
hematocrit
red blood cells (RBCs) have?
- no nucleus, cannot reproduce
- hemoglobin (Hb)
______:
- replace regularly via hematopoiesis
- life span ~4 months
- produced and destroyed at equal rates
RBCs
_____: oxygen-transporting protein in RBC
hemoglobin
_____: thickness of blood (due to red blood cells)
blood viscosity
if hematocrit _____, then viscosity ______.
increases; increases
what are the two main baroreceptors that sense pressure?
aortic and carotid artery baroreceptors
What are the normal ranges for resting heart rate (RHR)?
- untrained HR: 60 to 80 beats/min
- trained HR: as low as 30 to 40 beats/min
what affects resting heart rate?
affected by neural tone, temperature, altitude
_____: HR increases above HR at rest just before start of exercise
anticipatory response
according to cardiovascular responses. when resting heart rate is going through parasympathetic withdrawal what is happening?
vagal tone is decreasing
according to cardiovascular responses, when resting heart rate is going through sympathetic stimulation what is happening?
catecholamine is increasing
heart rate during exercise is?
directly proportional to exercise intensity.
_____: highest HR achieved in all-out effort to volitional fatigue.
maximum HR
_____:
- point of plateau
- optimal HR for meeting circulatory demands at a given submaximal intensity
- if intensity increases, so does ?
- adjustment to new intensity takes 2 to 3 min
steady-state HR
_____: basis for simple exercise tests that estimate aerobic fitness.
steady-state HR
_____: increases with increased intensity up to 40 to 60% VO 2 Max
stroke volume (SV)
what are factors that increase stroke volume?
- increased venous return and preload
- increased contractility
- decreased afterload
_____:
- increased stretch leads to increased contraction strength; known as the “Frank-Starling mechanism”
increased venous return and preload
increased norepinephrine or epinephrine leads to?
increased contractility
less aortic resistance due to a decrease in total peripheral resistance (vasodilation of vessels in exercising muscle)
decreased afterload
what is the Fick Equation?
O2 consumption of a tissue depends on blood flow to the tissue and the amount of O2 extracted by that tissue.
what is the blood oxygen content when the blood is resting?
~ 6 mL O2 per 100 mL blood
what is the blood oxygen content when you are hitting max exercise?
~ 18mL O2 per 100 mL blood (almost triple)
according to cardiovascular responses blood pressure during endurance exercise . . . ?
- systolic BP increases proportional to exercise intensity
- diastolic BP does not change or slightly decrease
- mean arterial pressure (MAP) increases
_____: leads to periodic large increases in MAP
- up to 480/350 mmHg
- more common when using valsalva maneuver
resistance exercise
what is the proper breathing technique?
- concentric: exhale
- eccentric: inhale
_____:
- involves expiring agents closed epiglottis and contraction of trunk musculature
- increases intraabdominal and intrathoracic pressure
- can hinder venous return, causing: dizziness, disorientation, excessively high BP, syncope
avoid valsalva maneuver
When there is an increase in cardiac output that leads to increased available blood flow, because there is an increase in blood flow to areas with greatest metabolic need (exercising muscle) this is referring to?
blood flow redistribution
_____: shunts blood away from less-active regions
- kidneys
- splanchnic circulation (liver, pancreas, GI)
sympathetic vasoconstriction
_____: permits additional blood flow in exercising muscle.
local vasodilation
sympathetic vasoconstriction in muscle offset by?
sympatholysis
