Cardiovascular (Topic 11) Flashcards
What are the two main circulations of the cardiovascular system? (2)
- pulmonary (lungs)
- systemic (everywhere else)
What carries O-poor blood to the lungs and O-rich back to the heart? (3)
pulmonary loops
What carries O-rich blood from the heart and O-poor back to the heart? (3)
systemic loop
Is the cardiovascular open or closed system? (2)
closed
What are the kinds of blood vessels? (3)
- arteries
- arterioles
- capillaries
- venules
- veins
- vena cavae
Where do arteries carry blood? (3)
away from the heart
Where do veins carry blood? (3)
to the heart
Go over slide 4
okkk
What causes valves to open and close? (5)
pressure differences
What is prolapse? (5)
What happens when there is too much pressure in the ventricles and the AV valves open backwards (up)
- (valve pushed up into the atria during ventricular contraction)
chordae tendinea and papillary muscles work together to do what? (5)
work together to prevent prolapse
What is the heart innervated by? (6)
innervated by both sympathetic and parasympathetic nerve fibers
What do sympathetic nerve fibers release? (6)
Norepinephrine (↑♥rate, ↑contractility, ↑conduction rate)
What do parasympathetic nerve fibers release? (6)
acetylcholine (decrease ♥rate, decrease contractility, decrease conduction rate)
Practice slide 7
uh huh honey
What is the conducting system? (8)
electrical contact with muscle cells
How does the electrical signal get from cell to cell? (8)
Gap Junctions
What does the Sinoatrial node (SA) “pacemaker” do? (8)
- controls the electrical impulses which cause contraction.
- Cells in SA node have faster cycling and drive the other node cells.
- in the atria
What do node cells do? (8)
spontaneous cyclic depolarization
- do not require input or signal
What does the Atrioventricular node (AV) do? (8)
delays the stimulus (100 ms)
What does the bundle of His do? (8)
transmits the stimulus to the ventricles
- right and left bundle branches
What do the perkinje fibers do? (8)
distribute the stimulus to myocardial cells
What does the P-wave account for? (10)
atrial depolarization
What does the QRS-complex account for? (10)
ventricular depolarization
- Atrial repolarization is masked by QRS
- Abnormal trace reveals abnormal heart function
What does the T-wave account for? (10)
ventricular repolarization
What is an arrhythmia? (11)
uncoordinated atrial and ventricular contractions (electrical signaling).
- Can be treated with medication or go untreated ( cause common)
What is atrial fibrillation (disorder)? (11)
rapid and irregular contractions not controlled by SA node.
- An atrial fibrillation can cause clotting and inefficient filling of the ventricles.
- A ventricular fibrillation is life threatening.
What is atrial defibrillation (treatment)? (11)
application of an electrical stimulus to “reset” the cells.
What do pacemakers do? (11)
The device delivers the electrical stimulus rather than the SA node.
- stronger than SA node so it overrides it
- for chronic issues
What is the cardiac cycle? (12)
all the events involved with the blood flow through the heart during one heart beat.
What is systole? (12)
the contraction phase.
- Isovolumetric contraction: volume constant, valves closed
- Ventricular ejection: valve opens, blood flows out
What is diastole? (12)
the relaxation phase.
- Isovolumetric relaxation: volume constant, valves closed
- Ventricular filling: AV valves open
What happens when ventricles relax? (13)
- Pressure DECREASE
- AV valves OPEN
- semilunar valves CLOSE
What happens when ventricles contract? (13)
- Pressure INCREASE
- AV valves CLOSE
- semilunar valves OPEN
What are the two sounds normally heard with a stethoscope? (15)
“lub” closure of the AV valves
“dub” closure of pulmonary and aortic valves
- any other sounds are heart murmurs
What are most heart murmurs caused by? (16)
defects of the valves
- Insufficiency (imperfect closure) then a swishing sound is heard.
- Stenosis (narrowed) a high pitched sound or a click can be heard.
What is laminar flow? (16)
smooth and quiet
- cannot be heard
What is turbulent flow? (16)
narrowed valve/ murmur
- can be heard
What is turbulent backflow? (16)
leaky valve/ murmur
- can be heard
What is cardiac output? (17)
amount of blood pumped out of each ventricle in one minute
What is heart rate? (17)
beat per minute
What is stroke volume? (17)
volume per beat
What is cardiac output formula? (17)
CO (vol/min) = HR x SV
What is the normal cardiac output? (17)
5.25 L/Min
If blood volume drops or if the heart weakens, then SV ______ and CO is maintained by ______HR (18)
- declines
- increasing
In a healthy system SV is _______ (18)
fairly constant
What is positive chronotropic factors? (18)
increase heart rate
What is negative chronotropic factors? (18)
decrease heart rate
How is heart rate controlled? (18)
by the input from the nervous system
How to calculate stroke volume? (19)
the difference between the end diastolic volume and the end systolic volume
- SV = EDV - ESV
How much blood does the heart pump? (19)
pumps about 60% of the blood in its chambers (~70 mL).
What is stroke volume influenced by? (19)
- Preload
- Magnitude of sympathetic stimulation to the ventricles
- Afterload
What is preload? (19)
volume of blood in heart before contraction
What is afterload? (19)
arterial pressure that the heart is pumping against
(the pressure that the ventricles must overcome to force open the semilunar valves)
What is the frank-starling mechanism? (20)
heart muscles produce maximal power when more stretched than at rest.
What happens to Stroke Volume as End-diastolic volume increases? (20)
stroke volume increases
How does sympathetic stimulation affect cardiac output? (21)
- increases stroke volume because it increases contractility
- also increases heart rate
Why would a more forceful contraction expel more blood with each pump? (21)
the ventricles are never completely empty of blood
What can increase afterload? (22)
Anything that increases systemic or pulmonary arterial pressure
ex: hypertension
What is hypertension? (22)
high blood pressure
- above 140/90
Primary causes:
- High blood volume (usually due to high sodium levels)
- Decreased arterial compliance
What is arteriosclerosis? (23)
Thickening or hardening of the arteries. It results is the loss of elasticity (happens with age)
What is atherosclerosis?
forming of plaques
- as it gets thicker, lumin gets smaller and can cause blockage (also reduces compliance/less stretchy)
- a specific type of arteriosclerosis
What is coronary artery disease? (24)
atherosclerosis of arteries that supply the heart tissue
What is a myocardial infarction? (25)
heart attack
- tissue damage due to decreased blood supply
What is a stroke? (25)
tissue damage in the brain
What are the two types of strokes? (25)
- hemorrhagic: due to a blood leak (tear of vessel)
- ischemic: plaque build-up
What is an echocardiogram? (26)
Noninvasive technique that uses ultrasonic waves. This technique can detect the abnormal functioning of cardiac valves or contractions of the cardiac walls, and can also be used to measure ejection fraction.
What is a mitral valve prolapse? (26)
left AV valve (mitral valve) prolapses (pushed open backwards)
- Blood leaking back into the atrium
- Reducing cardiac output
- Arrhythmia
- Perhaps increasing risk of endocardial infection
What are the different types of arteries? (27)
- Elastic arteries
- Muscular arteries
- Arterioles
What is the endothelium? (27)
the inner lining of all blood vessels
What is the difference between arteries and veins? (27)
- Arteries have thicker, smooth-muscle walls (smaller opening)
What are capillaries composed of? (27)
simple squamous epithelial cells (just the endothelium lining)
What is systolic? (28)
Maximum arterial pressure occurs peak ventricular ejection
What is diastolic? (28)
minimum pressure occurs just before ventricular ejection begins
What is pulse pressure? (28)
= systolic - diastolic
Arterial mean and pulse pressure ______ with downstream distance from the heart (28)
decreases
Pressures in systemic mostly _____ than in pulmonary circulation (28)
higher
Review graph on 28
arteries: systemic circulation pressure is generally a lot higher than pulmonary(it takes greater pressure to get blood to your extremities)
arterioles: drops
capillaries: drops more
venules: considerably lower than arteries
veins: systolic drops lower than pulmonary
How to calculate compliance (29)
delta volume / delta pressure
The higher the compliance of a structure, the ___ easily it can be stretched. (29)
more
What are arteries often called? Why? (29)
pressure reservoirs
- reservoirs because of the elastic recoil. They are not as compliant as veins.
What are characteristics of elastic arteries? (30)
- The major example of an elastic artery is the aorta.
- Large lumen vessels (low resistance) that contain more elastin than the muscular arteries.
- Serve as “pressure reservoirs” ‒‒ they expand and contract (recoil) as blood is ejected by the heart. This allows blood flow to be continuous.
What would happen if your aorta did not have large compliance? (30)
- the aorta could rupture
What are characteristics of muscular arteries? (30)
- Deliver blood to specific organs (mesenteric artery, renal artery etc.).
- Have the most smooth muscle and are very active in vasoconstriction.
- Play a large role in the regulation of blood pressure.
What is normal arterial blood pressure? Hypertensive? Hypotensive? (31)
- Normal = 120 /80 mmHg
- hypertensive = 140/90 mm Hg
- hypotensive = 90/60 mm Hg
What happens to systolic and diastolic pressure as we get older? (31)
- systolic increases
- diastolic decreases
Why does arteriosclerosis cause its effect on systolic and diastolic pressure? (31)
Go over slide 32
oh yeah blood pressure taking
How do you hear Korotkoff/s sounds? (32)
Sphygmomanometer for pressure + stethoscope to hear
Characteristics of arterioles (33)
- Smallest arteries.
- Function controlled by neural, hormonal, paracrine.
- Control minute-to-minute blood flow into the capillary beds.
- If they contract, reduced blood flow
- If they dilate, increased blood flow
What is the formula for flow? (34)
delta P / R
How do you decrease flow if pressure stays the same? (34)
vasoconstriction
How do you increase flow if pressure stays the same? (34)
vasodilation
What are capillaries? (35)
smallest blood vessels and sites of exchange
What are capillaries? (35)
smallest blood vessels and sites of exchange
What are the three types of capillaries? (35)
- continuous
- fenestrated
- sinusoidal
Characteristics of continuous capillaries (35)
found in skin, muscle
most common kind have tight junctions.
Characteristics of fenestrated capillaries (35)
more permeable — intestines, hormone-producing tissues, kidneys, etc.
Characteristics of sinusoidal capillaries (35)
- only one with an incomplete basement membrane
- found in the liver, bone marrow and lymphoid tissues
Go over anatomy of a capillary on slide 36
uh huh
What do metarterioles do? (36)
- connects arteriole to venule
- capillaries exit from them
What do precapillary sphincters do? (36)
- controls blood flow through the capillary bed by local metabolic factors
What has to move across the capillary? (37)
CO2?
Glucose?
O2?
What is the main mode of transport in capillaries? (37)
diffusion:
- lipid soluble cross the membrane
- water soluble passes through water-filled channels (pores) in the endothelium
also Vesicle transport and Bulk flow
What capillary movement only occurs in the brain? (37)
mediated transport (blood-brain barrier)
What is bulk flow? (38)
- movement of protein-free plasma
- Distributes the extracellular fluid volume.
- Direction of flow: net hydrostatic pressure and the net osmotic pressure.
Explain filtration and absorption in terms of bulk flow (38)
- more filtration (plasma to interstitial fluid) on arteriole side
- more absorption (interstitial fluid to plasma) on venule side
- When fluid gets filtered out, it leaves solutes in capillary resulting in high osmotic pressure
- From arteriole to venule: decrease blood pressure, increase osmotic pressure
Characteristics of veins (39)
- The walls are thinner than arteries, so they often appear collapsed in Histological slides.
- veins have less smooth muscle than arteries
- Veins are highly distensible (more compliant), so they act as blood reservoirs.
- veins have valves to keep blood from flowing backwards
- Blood pressure in veins is 10-15 mmHg. (weak)
What maintains the pressure and returns blood to the heart in veins? (40)
- Smooth muscle contractions (Sympathetic nervous system)
- Skeletal muscle pump (with valves)
- Respiratory pump
What are varicose veins? (40)
veins that have become dilated and tortuous because of incompetent (leaky) valves.
What is blood made of? (41)
cells and cell fragments
- erythrocytes (RBC)
- leukocytes (WBC)
- platelets
What is plasma made of? (41)
- proteins
- ions
- glucose and other nutrients
What is a hematocrit? (41)
% of components
- plasma 55%
- Buffy coat
- erythrocytes 45%
What is normal blood volume? (41)
5.5L
Go over slide 42
ok
What are eryhtrocytes? (43)
red blood cells
What are leukocytes? (43)
White blood cells
What do all blood cells come from? (44)
All blood cells come from a single population of bone marrow cells
What is hemopoiesis? (44)
production of blood cells and platelets from bone cells
What is a megakaryocyte? (44)
basically a giant platelets
- platelets are small pieces of megakaryocytes
Characteristics of erythrocytes (RBC) (45)
- Transport oxygen and carbon dioxide. Biconcave disk in shape with a flexible membrane.
- Cell Lifespan:
- Produced in bone marrow
- Lose nucleus and most organelles during
maturation
- Circulate for 120 days
- Destroyed in spleen and kidney
What is hemoglobin? (45)
- Molecule that carries O2 and CO2
- Contains 4 iron atoms
- Needed in diet, 25% stored in liver
Why is the biconcave shape of RBC important? (45)
it increases surface area for gas exchange
What are the physiological process to stop bleeding? (46)
- vasoconstriction
- formation of platelet plug
- blood coagulation (clotting)
What are the physiological process to stop bleeding? (46)
- vasoconstriction
- formation of platelet plug
- blood coagulation (clotting)
What is blood clotting? (47)
Blood converted into solid gel called clot or thrombus
- Occurs around platelet plug
- Dominant hemostatic defense mechanism
