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hemodynamics schoolcraft college anatomy 2
book is by martini and roth
176
Anatomy
Undergraduate 1
09/16/2012

Additional Anatomy Flashcards

 


 

Cards

Term
conducting system 
Definition
coordinates those chamber contractions to move blood through both pumps and out to the body
Term
contractile 
Definition
cells squeeze the heart from bottom to top in a smooth rhythmic motion
Term
ECG
Definition
electrical impulses that drive the contractions can be measured with
Term
Contractile Cells
Definition
– produce contractions that move blood
Term
Autorhythmic Cells 
Definition

the cells that coordinate

    the contractions 

 
Term
conducting system
Definition

the contractions 

called the 

Term

wall of right atrium

 
Definition

SA node – sinoatrial node

 
Term

junction between right atrium and right ventricle

 
Definition

AV node – atrioventricular node

 
Term
SA node 
Definition
= sets the pace
Term
AV node 
Definition
= receives message from SA node
Term

conducting cells

 
Definition

throughout myocardium

in AV bundle

in bundle branches

in Purkinje fibers

 
Term
Automaticity
Definition

most of these conducting cells are smaller than the working contractile cells

and those in the nodes are UNSTABLE

they cannot maintain a STABLE resting potential

so these cardiac muscle fibers are SELF-EXCITABLE

they depolarize spontaneously and cause those nearby to also depolarize

 
Term
PREPOTENTIAL (or pacemaker potential
Definition
this gradual depolarization is called a 
Term
a prepotential 
Definition

is a gradual depolarization

slow inflow of sodium ions

no outflow of potassium

Term

SA 

80-100 / minute

 
Definition
these nodes spontaneously depolarize the fastest
Term
40-60 / minute
Definition
AV node generates action potentials at 
Term
SA 
Definition
this NODE ESTABLISHES THE HEART RATE
Term

parasympathetic system – vagus nerve

 
Definition
your normal resting rate is lower than the above 80-100/ bpm because of the 
Term
noncontractile cel
Definition

– these begin and distribute the impulses

Initiate action potentials 

these are only a small percentage of the heart cel

Term
Autorhythmic cells
Definition
noncontractile cells are a type of
Term
SA Node 
Definition

your personal pacemaker

sends out an action potential which reaches the AV node in a fraction of a second

message sent along internodal pathways – see yellow lines

BUT – stimulus is also passed to the muscle cells of both atria

so both atria contract

stimulus only reaches throughout the atria

ventricles do not feel the stimulus

 
Term
av node
Definition

these cells are smaller than the cells that conducted the impulse here from the SA node

so impulse SLOWS

impulse is delayed here

allows atria time to finish contracting

Term

230 bpm higher than that is abnormal state and movement of blood through the pump is dangerously reduced

 
Definition
fastest the AV node can pass impulses on throughout the heart is 
Term
av bundle
Definition
this is the electrical connection between the atria and ventricles
Term
AV bundle 
Definition

damage this and ventricles don’t get the message

 
Term
Purkinje fibers
Definition

radiate from apex toward the base (top) of heart

cause ventricles to contract in a rhythmic wave from inferior to superior aspect

pushing blood toward the exit vessels

SO BOTH VENTRICLES CONTRACT AT ABOUT THE SAME TIME

then the heart rests

 
Term
conduction deficits 
Definition

= damage to any part of this conduction pathway

could slow it down or cause timing disruptions

ECG is used to diagnose

Term

= INTRINSIC

DOES NOT NEED THE NERVOUS SYSTEM

 
Definition
depolarization leading to contraction of heart is
Term
basic rhythm
Definition
the nervous system sends autonomic fibers to the heart to ALTER the 
Term
electrocardiogram (ECG
Definition
Electrical activity is recorded by 
Term
P wave 
Definition
corresponds to depolarization of SA node
Term
QRS complex 
Definition
corresponds to ventricular depolarization
Term
T wave 
Definition
corresponds to ventricular repolarization
Term
Atrial repolarization 
Definition
record is masked by the larger QRS complex
Term
Contractile Cel
Definition
these do the major work of the heart
are about 99% of heart cells
recall skeletal muscle and the action potential
calcium binding to troponin initiating contraction..
BUT there are some differences in the process in cardiac muscle
nature of the action potential
source of the calcium
duration of the contraction
 
Term

in the heart muscle –

the action potential  lasts much longer (250ms +)

compare to skeletal muscle = (1 -2ms)

so the duration  of contraction is also much longer compared to skeletal muscle 

prevents – fast and ineffective contractions which would make the ‘pump’ useless

 
Definition
Action potential and contraction duration have to be different in 
Term
rapid depolarization 
Definition

–nearby cell has just passed on an impulse

sodium channels open and sodium rushes into cell

this depolarizes the membrane

channels quickly close

Term

the plateau

 
Definition

as sodium channels are closing – calcium channels (slow channels) open slowly and stay open a relatively long time

so the transmembrane (across the membrane) potential remains near 0mV for awhile

THIS IS THE MAJOR DIFFERENCE BETWEEN THE ACTION POTENTIAL IN SKELETAL MJSCLE AND CARDIAC MUSCLE

 
Term
The Plateau
Definition

transmembrane potential drops below 0

note green line starting back down

cell begins throwing sodium out BUT…

calcium channels open (slow calcium channels)

so the loss of  positive sodium is balanced by the gain of positive calcium  (2)

accounts for the slow downward trend of the mV line

finally the calcium channels begin to close

now the slow potassium channels begin opening (3)

potassium rushes out of cell

now cell must rearrange ions to suit

THIS LIMITS HEART RATE

 
Term
The Action Potential
Definition

inside the myocyte  in ventricle = -90mV

when nearby cells stimulated = starts to lose ions and becomes -75mV

that is threshold and impulse proceeds

rapidly sodium influxes and depolarization occurs

note straight green line from 4 to 1

the line is above the 0 mark = depolarization ( reversal of charge) 

sodium channels close quickly

and sodium is pumped out of the cell

 
Term
Sequence of electrical events – Action Potential
Definition

depolarization when sodium enters

this also opens channels for calcium to enter

once inside the calcium ions stimulate the SR to release the rest of the calcium (slow calcium channels)

so the depolarization wave moves down the T tubules to the SR

next sodium is no longer entering and is being pumped out

the depolarization is briefly prolonged by the calcium

this is the PLATEAU

potassium is pumped out to repolarize the membrane

then the pumps rearrange the ions…..

 
Term
Calcium
Definition

recall that the calcium entered during plateau

the entering calcium was about 20% of that required for contraction

but its arrival triggers the rest to be released from the sarcoplasmic reticulum

THIS IS ANOTHER REASON WHY CALCIUM IS SO IMPORTANT  AND SO TIGHTLY REGULATED

calcium channel blockers (verapamil) decrease the contractility of the heart  (BP med)

 
Term

there are more mitochondria in cardiac muscle than in skeletal muscle

cardiac muscle uses aerobic respiration

anaerobic metabolism (ischemic condition) would produce too much acid, which hinders ATP production

gap junctions would close and isolate the damaged cells

heart uses glucose and fatty acids

also uses lactic acid from skeletal muscle

has a reserve of oxygen in myoglobin

 
Definition
From where does the energy for all this come
Term
Cardiac cycle 
Definition
refers to all events associated with blood flow through the heart –DURING ONE COMPLETE HEARTBEAT
Term
Systole 
Definition
– contraction of heart muscle
Term
Diastole 
Definition
relaxation of heart muscle
Term
diastole 
Definition
heart is at rest but is filling again
Term

Remember – atria go through systole and diastole then the ventricles go through systole and diastole

 
Definition

Remember – atria go through systole and diastole then the ventricles go through systole and diastole

 
Term
mid-to-late diastole
Definition

heart is in total relaxation

heart blood pressure is low as blood enters atria and flows into ventricles (passively)

AV valves are open, 

 
Term
atrial systole occurs – 1
Definition

atria contract and squeeze blood

THIS pushes rest of blood into ventricles – fills them up

now the ventricles are filled – called END DIASTOLIC VOLUME (EDV)  - lots of blood in ventricles now

 
Term

Ventricular systole - 2

 
Definition

Atria relax (diastole for atria) 

Rising ventricular pressure (contraction)results in closing of AV valves (blood pushes back against valves)

called isovolumetric contraction

ventricles are starting to squeeze out the contained blood, but no valves are open yet

Ventricular ejection phase opens the semilunar valves (when ventricles squeeze – blood has nowhere to go but out through the SL valves)

 
Term
semilunar valves
Definition
the squeezing of the ventricles will eventually push open the
Term
called the STROKE VOLUME
Definition
each ventricle will eject about 80 ml of blood
Term
the EJECTION FRACTION
Definition
amounts to about 60% of how much blood was in the ventricle – this percentage is called the 
Term

Early diastole

 
Definition

Ventricles relax -3

Backflow of blood in aorta and pulmonary trunk has closed semilunar valves

remember - some blood remains in the ventricles

called END SYSTOLIC VOLUME (ESV)

ABOUT 40% OF BLOOD STILL IN HEART

what has been squeezed out = EJECTION FRACTION

 
Term
closing of heart valves
Definition
Heart sounds (lub-dup) are associated with 
Term
systole (contraction of heart)
Definition
First sound occurs as AV valves close and signifies beginning of 
Term
ventricular diastole (relaxation of heart)
Definition
Second sound occurs when SL valves close at the beginning of 
Term

blood flow through the heart is controlled by pressure changes

blood flows down its pressure gradient

pushes through any weaker opening

the pressure changes are caused by the contraction and relaxation of the myocardium

the ventricles fill mostly by passive flow of blood – explains why damage to atria is survivable, while ventricular damage is life-threatening

 
Definition

blood flow through the heart is controlled by pressure changes

blood flows down its pressure gradient

pushes through any weaker opening

the pressure changes are caused by the contraction and relaxation of the myocardium

the ventricles fill mostly by passive flow of blood – explains why damage to atria is survivable, while ventricular damage is life-threatening

 
Term
closing of heart valves
Definition
Heart sounds (lub-dup) are associated with 
Term
AV valves close and signifies beginning of systole (contraction of heart)
Definition
First sound occurs as 
Term
SL valves close at the beginning of ventricular diastole (relaxation of heart)
Definition
Second sound occurs when
Term
EDV 
Definition
– amount of blood in each ventricle just before the ventricle goes to work contracting
Term
ESV- 
Definition
amount of blood that is left in the ventricle after it has contracted
Term
SV 
Definition
amount of blood the is pumped out of each ventricle in one contraction or beat  (EDV  -  ESV  = 
Term
ejection fraction- 
Definition
a percent – this is the percent of the blood leaving the heart
Term
Cardiac Output (CO) 
Definition
is the amount of blood pumped by each ventricle in one minute
Term
CO 
Definition
is the product of heart rate (HR) times stroke volume (SV)
Term
HR 
Definition
is the number of heart beats per minute
Term
SV 
Definition
is the amount of blood pumped out by a ventricle with each beat
Term
Cardiac reserve 
Definition
is the difference between resting and maximal CO
Term
left ventricle)
Definition
(physicians are most interested in output of 
Term
HR (75 beats/min) x SV (70 ml/beat)
Definition
CO (ml/min) = 
Term
by the sympathetic cardioacceleratory center 
Definition
Heart is stimulated 
Term
parasympathetic cardioinhibitory center – puts the brakes on
Definition
Heart is inhibited by the 
Term
stress, anxiety, excitement, or exercise 
Definition
Sympathetic nervous system (SNS) stimulation is activated by 
Term
is mediated by acetylcholine and opposes the SNS 
Definition
Parasympathetic nervous system (PNS) stimulation is
Term

the autonomic stimulation, slowing heart rate and causing vagal tone

vagus – puts the brakes on

 
Definition
PNS dominates the 
Term

norepinephrine

more calcium enters which increases CONTRACTILITY

glucagon, thyroxine, digitalis also enhance contractility

 
Definition
sympathetic stimulation releases 
Term
STROKE VOLUME 
Definition

tells us how much per squeeze

Lots of factors come into play here

preload

afterload

ability to contract – contractility

 
Term
The EDV
Definition

blood waiting to be pumped out of the ventricle

how much might this be????

how long did the ventricle have to fill up?

THE FASTER THE HEART - BEAT THE SHORTER THE AVAILABLE FILLING TIME

how fast was the blood moving from the atrium to the ventricle

how fast was it coming back from all over the body?

 
Term
The ESV
Definition

this is the blood that didn’t make it out during the contraction

remember – there is some blood left behind

THE STROKE VOLUME HAS BEEN EJECTED

How much managed to exit the heart, leaving behind the ESV??

what was the preload?

how well did the ventricle squeeze?

what was the afterload?

 
Term

Preload – amount ventricles are stretched by contained blood 

affects end diastolic (relaxation) volume – how much blood is in ventricle at end of relaxation phase

greater the EDV (end diastolic volume)-   the larger the preload (of blood)

when you are at rest = your EDV is comparatively LOW

you’re not stretching your ventricles much

if you exercise = EDV increases and myocardium stretches further – more blood pumped out of heart

 
Definition
Factors Affecting Stroke Volume How much are you squeezing out per minute
Term
Preload
Definition

this is how much blood is ready to go before the ventricles contract

more in = more out

 
Term
Frank-Starling Law of the Heart rubber band reaction
Definition

Preload, or degree of stretch, of cardiac muscle cells before they contract is the critical factor controlling stroke volume

Law – ‘more in = more out’

stretch the ventricular muscle = it contracts harder

Exercise increases venous return to the heart, increasing SV (because preload is more)

but too much = ventricle can’t pump well =CHF

Blood loss and extremely rapid heartbeat will decrease SV=preload is less

Ex. -not much blood entering and heart will increase pace to try to keep up the pressure – but output will be less

 
Term

Contractility – cardiac cell contractile force due to factors other than EDV

Ex. Calcium, thyroxine, epinephrine, digitalis-increase

results in more blood ejected from heart

Ex. damaged heart = decreased contractility = stroke volume down

Afterload – back pressure exerted by blood in the large arteries leaving the heart

‘resistance in the pipes’ – What is in the way of blood leaving the heart?

clots, pulmonary edema = higher afterload

if increased afterload then stroke volume goes down

If HTN = ventricles don’t eject as much blood = more blood remains in heart = reduced stroke volume

 
Definition
Other Factors Affecting Stroke Volume
Term

Coronary atherosclerosis

Persistent high blood pressure

Multiple myocardial infarcts

Pulmonary problems

Valve problems

Definition

Congestive heart failure (CHF) is caused by:

 
Term
Fibrillations
Definition

small areas of the heart muscle are no longer coordinated with the rest of the muscles

blood is no longer effectively moved through the heart

 
Term
Ventricular fibrillation 
Definition
Atrial fibrillation – not as dangerous as…
Term
Ventricular fibrillation 
Definition
– can be caused by blocked coronary artery, toxic drugs, electric shock, traumatic injury
Term
bradycardia 
Definition

heart rate under 60 beats / minute

in athletes = hypertrophy and SV is higher= resting heart rate can be lower and still provide same output

but in diseased patient = not enough blood delivery to the tissues

 
Term
tachycardia 
Definition

– more than 100 beats  minute

which way does stoke volume go?

down because no time to fill

what happens to lung’s ability to exchange oxygen?

not enough time for RBCs to exchange

 
Term

decrease the workload to allow repair

so give vasodilator and drugs to decrease heart rate

 
Definition

 treatment for a mild heart attack with no drop in arterial pressure

 
Term

first priority is to maintain arterial pressure

give vasoconstrictor

 
Definition

 treatment for severe HA that shows rapidly dropping arterial pressure

 
Term
also give vasodilator but make contractions more powerful (DIG)
Definition
treatment for moderate ha
Term

Blood pressure

Resistance

Heart must push with enough pressure to overcome the resistance in the network

So the more pressure – the more flow

 BUT the more resistance – the LESS flow

There is a big pressure gradient between the aorta and the far capillaries

Various control centers will adjust the whole system

 
Definition
Blood flow determined by 
Term
Blood Pressure (BP)
Definition
Force per unit area exerted on the wall of a blood vessel by its contained blood 
Term
millimeters of mercury (mm Hg)
Definition
Blood Pressure (BP) is expressed as
Term
 systemic arterial BP in large arteries near the heart – most pressure here
Definition
 
 bp is Measured in reference to
 
Term

Referred to as peripheral resistance (PR)

 
Definition

Resistance – opposition to flow 

Measure of the amount of friction blood encounters

 
Term

vessels themselves – length and diameter

thickness of blood - viscosity

flow rates across surfaces – are there eddies or turbulence?

 
Definition

So what might cause RESISTANCE?

 
Term
FRICTION
Definition
Vessels resist-most importantly because of 
Term
total blood vessel length- 
Definition

the longer the vessel the more friction 

the farther the blood travels – the more resistance is encountered

Ex. adding pounds = need for more vessels = more peripheral resistance

 
Term
blood vessel diameter 
Definition

friction occurs next to vessel wall

Ex. smaller the vessel the more resistance – larger vessels are not very resistant to blood flow

the blood near the center of the flow is not influenced by the sides of the vessel

 
Term
blood viscosity 
Definition

how thick is your blood?

compare syrup to water as it flows

healthy person has stable viscosity

 
Term
turbulence 
Definition

eddies and swirls

occurs in heart and larger vessels

not supposed to occur in smaller vessels - if so = damage

 
Term
peripheral resistance
Definition
Changes in vessel diameter are frequent and significantly alter
Term
Small-diameter arterioles 
Definition

are the major determinants of peripheral resistance

Fatty plaques from atherosclerosis: 

Cause turbulent blood flow

Dramatically increase resistance due to turbulence

turbulence is not smooth flow

 
Term

Resistance makes more of an impact on tissue perfusion

Vessels can dilate and feed a particular area especially well, without the rest of circulation being disturbed

The heart will still be pumping out the same amount of blood

but arterioles may provide MORE or LESS resistance – this has the most impact on resistance

 
Definition

Resistance makes more of an impact on tissue perfusion

Vessels can dilate and feed a particular area especially well, without the rest of circulation being disturbed

The heart will still be pumping out the same amount of blood

but arterioles may provide MORE or LESS resistance – this has the most impact on resistance

 
Term
pressure gradient, always moving from higher- to lower-pressure areas
Definition
The pumping action of the heart generates blood flow through the vessels along a 
Term
opposed by resistance
Definition
So blood pressure goes UP  when flow is 
Term
the vessels – the more pressure, the harder the heart works
Definition
Cardiac output has to overcome pressure in 
Term
Systemic pressure
Definition

Is highest in the aorta

Declines throughout the length of the pathway

Is 0 mm Hg in the right atrium

 
Term
arterioles
Definition
The steepest change in blood pressure occurs in 
Term
Systolic pressure 
Definition
pressure exerted on arterial walls during ventricular contraction 
Term
Diastolic pressure 
Definition
– lowest level of arterial pressure during a ventricular cycle
Term
Pulse pressure 
Definition
the difference between systolic and diastolic pressure – feel this in your wrist
Term
Mean arterial pressure (MAP) 
Definition
pressure that propels the blood to the tissues – this is an average (70 – 110mgHb
Term
farther from the heart
Definition
MAP and pulse decline as you get
Term
HYPERTENSION
Definition
above 140/90 is considered 
Term
systolic pressure over diastolic pressure
Definition
113 / 76 is read as
Term

20 to 40 mm Hg

Low capillary pressure is desirable because high BP would rupture fragile, thin-walled capillaries

Lower BP is still sufficient to force filtrate out into interstitial space and distribute nutrients, gases, and hormones between blood and tissues

 
Definition
Capillary BP ranges from 
Term

20 mm Hg 

A cut vein has even blood flow; a lacerated artery flows in spurts

Venous return in the larger vessels offers less resistance and the blood flow increases

Venous BP is steady and changes little during the cardiac cycle
 
Definition
The pressure gradient in the venous system is only about
Term

Cooperation of the heart, blood vessels, and kidneys

Supervision of the brain

Definition
Maintaining blood pressure requires
Term
Venous Pressure
Definition

low, but determines amount of blood entering heart

veins become bigger closer to heart

less resistance

needs to overcome gravity

muscles compress

respiratory pump – rising pressure in thoracic cavity (exhalation) – pushes blood into the right atrium

 
Term
filtration 
Definition

works because of water pressure (hydrostatic)

solutes are moved as  solution flows past a membrane that allows them to pass through

 
Term
reabsorption 
Definition

works because of osmosis

osmotic pressure of a solution = how many solutes contribute to the attraction of water

blood colloid osmotic pressure or oncotic pressure

 

REMEMBER – solutes attract water – it wants to move toward the solutes to even out its own gradient

 
Term

net hydrostatic pressure =

 
Definition

add up the amount of force driving fluids out of blood (Ex. 35 mm Hg)

plus the amount of force of the fluid pushing back against the capillary (Ex. small, negligible value)

 
Term

net colloid osmotic pressure

 
Definition

add the attractive force (proteins) in the capillaries  to ‘lure’ water back into the capillary

plus the attractive force of the very few proteins in the nearby tissues (Ex. also negligible)

 
Term
NET FILTRATION PRESSURE
Definition

net hydrostatic pressure + net colloid osmotic pressure

 
Term
VASODILATORS
Definition

blood flows faster in that area

histamine dilates blood vessels

lactic acid from exercise

rising levels of hydrogen (pH is moving toward acid)

temperatures increase in that area

causes smooth muscles of precapillary sphincter to relax

 
Term
VASOCONSTRICTORS 
Definition

sphincters tighten

wounds – platelets and other chemicals cause vasoconstriction

cold

 
Term

cardiovascular center

the brain – medulla has
 
Definition

acceleratory part increases your cardiac output with sympathetic messages

inhibitory center uses the parasympathetic

Term
the sympathetic vasoconstrictor nerves 
Definition

– produce VASOMOTOR TONE

keeps arterioles a bit constricted

with small adjustments to arterioles – blood pressure (peripheral resistance) is controlled

 
Term

Pressure Receptors called BARORECEPTORS

 
Definition

sense the amount of stretch in various organs

in CV system – located

near internal carotid arteries (carotid sinus)

in wall of ascending aorta

in wall of right atrium

 
Term

parasympathetic nerves put the brakes on (Ach)

vasomotor center dilates vessels

 
Definition

what happens if pressure is sensed as too high?

 
Term

sympathetic nerves stimulate heart (EP)

sympathetic neurons constrict vessels

 
Definition

what happens if pressure is sensed as too low?

 
Term

Valsalva's maneuver

 
Definition

vena cava collapse, return to heart decreases

drop in CO and BP

aortic and carotid baroreceptors notice

heart rate increases and blood vessels constrict

release the pressure and heart returns to normal

but there will be a moment of high blood pressure

 
Term
Chemoreceptor Receptors  
Definition

sensory receptors notice changes in your carbon dioxide, oxygen, or pH levels

in blood AND CSF

these are specialized cells near the carotid sinus and in the aorta (carotid body, aortic body)

Term
Chemoreceptor Receptors 
Definition

if a rise in carbon dioxide (or a fall in pH)

these sensory cells notice  (cardiac center is stimulated)

so heart rate goes up, bv constrict (BP goes up) =blood pressure rises

 
Term
Adrenal medulla hormones 
Definition
norepinephrine and epinephrine increase blood pressure
Term
Antidiuretic hormone (ADH) 
Definition

causes intense vasoconstriction in cases of extremely low BP – saves water from exiting the body as urine

from pituitary

 
Term
Angiotensin II 
Definition
kidney release of renin generates angiotensin II, which causes vasoconstriction
Term
Atrial natriuretic peptide (ANP
Definition
causes blood volume and pressure to decline
Term
Inflammatory chemicals 
Definition
– histamine, prostacyclin, and kinins are potent vasodilators
Term
Alcohol 
Definition
causes BP to drop by inhibiting A
Term
blood volume
Definition
Long-term mechanisms control BP by altering
Term
to eliminate water, thus reducing BP
Definition
Increased BP stimulates the kidneys
Term

increase blood volume and BP

 
Definition
Decreased BP stimulates the kidneys to 
Term
Renal Regulation
Definition
Long-Term Mechanisms to Control BP
Term
Kidneys 
Definition
act directly and indirectly to maintain long-term blood pressure
Term

Direct renal mechanism

 
Definition

 alters blood volume by working faster to eliminate water (thus more urine)

 
Term
Indirect renal mechanism 
Definition

involves the renin-angiotensin mechanism

special cells in kidney sense a fall in BP, release renin, which ultimately…

gets aldosterone into the system to save sodium

makes you thirsty

stimulates ADH secretion to save water in collecting ducts

stimulates heart and constricts arterioles

 
Term
Vital signs 
Definition
pulse and blood pressure, along with respiratory rate and body temperature
Term
Pulse 
Definition
– pressure wave caused by the expansion and recoil of elastic arteries
Term
Radial pulse 
Definition
(taken on the radial artery at the wrist) is routinely used
Term
Variations in Blood Pressure
Definition

Blood pressure cycles over a 24-hour period

BP peaks in the morning (due to waxing and waning levels of retinoic acid)

Extrinsic factors such as age, sex, weight, race, mood, posture, socioeconomic status, and physical activity may also cause BP to var

Term
Hypotension 
Definition
low BP in which systolic pressure is below 100 mm Hg
Term
Hypertension
Definition

condition of sustained elevated arterial pressure of 140/90 or higher

Transient elevations are normal and can be caused by fever, physical exertion, and emotional upset

Chronic elevation is a major cause of heart failure, vascular disease, renal failure, and stroke

 
Term
Orthostatic hypotension 
Definition
temporary low BP and dizziness when suddenly rising from a sitting or reclining position 
Term
Chronic hypotension 
Definition
– hint of poor nutrition and warning sign for Addison’s disease
Term
Acute hypotension 
Definition

important sign of circulatory shock

Threat to patients undergoing surgery and those in intensive care units

 
Term
Primary or essential hypertension 
Definition
risk factors in primary hypertension include diet, obesity, age, race, heredity, stress, and smoking
Term
Secondary hypertension 
Definition
– due to identifiable disorders, including excessive renin secretion, arteriosclerosis, and endocrine disorde
Term

Delivery of oxygen and nutrients to, and removal of wastes from, tissue cells 

Gas exchange in the lungs

Absorption of nutrients from the digestive tract

Urine formation by the k

Definition
Blood flow, or tissue perfusion, is involved in
Term
Metabolic controls 
Definition
brain tissue is extremely sensitive to declines in pH, and increased carbon dioxide causes marked vasodilation
Term
Temperature Regulation
Definition

As temperature rises (e.g., heat exposure, fever, vigorous exercise):

Hypothalamic signals reduce vasomotor stimulation of the skin vessels-loosen the muscles

Heat radiates from the skin 

As temperature decreases, blood is shunted to deeper, more vital organs

Term
Blood Flow: Lungs
Definition

Blood flow in the pulmonary circulation is unusual in that:

It’s a quick trip through the lungs 

Arteries/arterioles are more like veins/venules (thin-walled, with large lumens)

Vessels are so thin that it doesn’t take much pressure to move blood through

Vessels will constrict in areas of lung where the alveoli are blocked…..

 
Term
Circulatory shock 
Definition

any condition in which blood vessels are inadequately filled and blood cannot circulate normally 

Not enough blood flow to meet tissue needs

 
Term
Hypovolemic shock 
Definition
results from large-scale blood loss 
Term
Vascular shock 
Definition

poor circulation resulting from extreme vasodilation

anaphylaxis or septic shock

 
Term

 

Cardiogenic shock  
Definition
the heart cannot sustain adequate circulation = pump failure
Term
When Things Go Wrong – compensation occurs
Definition

So - in loss of blood volume and pressure (hemorrhaging) = less pressure forcing water and solutes out into tissues

so reabsorption dominates

= more fluids back to blood

 

Other factors in cardiovascular problems - - - -

in dehydration – the concentration of those large plasma proteins increases = calling more water back into blood

 

BUT --if liver damage - not enough of those large plasma proteins to lure the water back to blood

person has ascites

 
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