CV system Flashcards
CV system function
supply cells/tissues with oxygen/nutrients and to remove wastes (CO2, urea)
CV system structures
heart
blood vessels
*blood is a connective tissue, not part of this system
cardiology
study of the heart and the diseases associated with it
heart
location: within mediastinum
size: closed fist, 300g
base of heart
wide superior portion
apex of heart
inferior point
heart coverings
serous (visceral & parietal) pericardium
fibrous pericardium
visceral pericardium
innermost delicate epithelium
parietal pericardium
inner lining of fibrous pericardium
pericardial cavity
between visceral and parietal pericardium and is filled with serous fluid
fibrous pericardium
outermost tough, fibrous protective CT layer the prevents over-stretching of the heart
heart wall
epicardium
myocardium
endocardium
epicardium
visceral pericardium
myocardium
cardiac muscle tissue, bulk of heart
endocardium
smooth inner lining of heart chambers and valves
simple squamous epithelium called endothelium
heart chambers
atria
ventricles
atria
upper chambers
receive blood from veins (PASSIVE)
thin walled
flaps called auricles
interatrial septum
not complete during fetal development
fossa ovalis is remnant of fetal foramen ovale
ventricles
pump blood from the heart into arteries (ACTIVE)
thick walled
trabecular carneae
trabecular carneae
irregular inner surface (ridges and folds)
arteries
carry blood away from the heart
high in O2, low in CO2 EXCEPT pulmonary arteries
aorta
blood from left ventricle to body
pulmonary arteries
blood from right ventricle to lungs via pulmonary trunk
coronary arteries
cary blood to myocardium
richest blood supply
veins
carry blood toward the heart
low in 02, high in CO2 EXCEPT the pulmonary veins
superior vena cava
blood from the head and upper limbs
inferior vena cava
blood from the trunk and lower limbs
coronary sinus
blood from myocardium
drains all coronary veins
posterior side of heart
pulmonary veins
blood from lungs to left atrium
2 from each side
ligamentum arteriosum
remnant of fetal ductus arteriosus
80% of blood goes from R->L atrium
20% of blood goes to R ventricle->pulmonary trunk-> ductus arteriosus->aortic arch
heart valves
atrioventricular (AV) valves
semilunar (SL) valves
atrioventricular valves
tricuspid (R AV)
bicuspid (L AV)
tricuspid valve
lies between right atrium and right ventricle
bicuspid valve
aka mitral valve
lies between the left atrium and left ventricle
chordae tendineae
tendon-like fibrous cords that connect the cusps of AV valves to the papillary muscle
prevent cusps from swinging back into atria
hold valves shut during contraction
papillary muscle
muscular columns that are located on inner surface of the ventricles
semilunar valves
pulmonary SL (R SL) aortic SL (L SL)
pulmonary SL valve
lies within pulmonary trunk
aortic SL valve
lies within aorta
pulmonary blood flow
right atrium (deoxygenated) tricuspid valve right ventricle pulmonary SL valve pulmonary trunk pulmonary arteries capillaries pulmonary veins left atrium bicuspid valve left ventricle aortic semilunar valve ascending aorta
coronary blood flow
ascending aorta coronary arteries left & right coronary arteries capillaries in myocardium cardiac veins coronary sinus right atrium
left coronary artery
circumflex branch (backside) anterior interventricular (descending) branch (aka widow maker)
right coronary artery
right marginal branch posterior interventricular (descending) branch
anastomoses
connections between 2 ore more branches of arteries that supply the same region with blood
provide alternate routs for blood to reach a particular region
cardiac veins
great cardiac vein (alongside widow maker)
middle cardiac vein (alongside posterior IV branch)
common causes of heart problems
blood clots
fatty atherosclerotic plaques
smooth muscle spasms w/in coronary vessels
ischemia
reduction of blood flow in the presence of normal oxygen
hypoxemia
reduction of oxygen with normal blood flow
hypoxia
reduction of oxygen and blood flow
angina pectoris
severe pain accompanied by myocardial ischemia
crushing pain radiating down left arm
labored breathing, weakness, dizziness, perspiration
during exertion, fades with rest
relieved by vasodilators (nitroglycerin)
stable angina
pain on exertion relieved with rest
unstable angina
pain on exertion, no relief with rest
usually due to atherosclerosis
Prinzmetal angina
associated with vasospasm
idiopathic
myocardial infarction
pathological term
ischemic necrosis due to lack of oxygen
caused by thrombus or embolus in coronary artery
may result in sudden death if conduction system interrupted and ventricular fibrillation occurs
heart attack
clinical term
MI tests
ECG (EKG): wider QRS, arrhythmias
troponin levels elevated w/in 30 minutes, normal within 5-7 days
CKMB - creatinine kinase, cardiac; elevated 1-2h after, normal w/in 2-3 days
neutrophilic response within 4-7 days; could result in cardiac tampanade
MI treatments
clot dissolving agents (TPA, streptokinase)
heparin
angioplasty
reperfusion damage
when oxygen deprived tissue’s blood supply is reestablished
formation of free radicals
damage to enzymes, neurotransmitters, nucleic acids, phospholipids
reperfusion damage implications
heart disease parkinson's alzheimer's cataracts rheumatoid arthritis aging
antioxidants
defend body against free radicals
include enzyme catalase, vitamin A, C, E
cardiac conduction system
sinoatrial (SA) node
atrioventricular (AV) node
atrioventricular (AV) bundle (right and left branches)
purkinje fibers
SA node
located in right uppermost atrial wall
aka pacemaker; initiates cardiac impulses (60-100bpm)
travels through atrial fibers via gap junctions in intercalated discs to AV node
AV node
located in interatrial septum
delay signal that allows for ventricular filling
impulse travels to AV bundles
AV bundles
aka bundle of His
only electrical connection between atria and ventricles
located in superior interventricular septum
enters both right & left branches downward toward apex and purkinje fibers
perkinje fibers
aka conduction myofibers
large diameter
located within papillary muscles of ventricles
conduct impulse into mass of ventricular muscle tissue
cause ventricles to contract
electrocardiogram (ECG/EKG)
recording of the electrical changes that occur in the myocardium during the cardiac cycle
EKG uses
evaluate conduction pathways
heart enlargement
heart regions damaged
rules to remember (EKG)
depolarization precedes contraction
repolarization precedes relaxation
heartbeat waves
P wave
QRS complex
T wave
P wave
small upward wave
represents atrial depolarization (movement of electrical impulse through atria)
0.1s after P wave begins, atria contract
QRS complex
begins as downward deflection, continues as large, upright, triangular wave, ends as downward wave
represents onset of ventricular depolarization
shortly after QRS begins, ventricles start to contract
T wave
dome-shaped, upward deflection
represents ventricular repolarization
just before ventricles relax
shape indicates slow process
enlarged P wave
enlargement of atrium possibly due to mitral stenosis
enlarged Q wave
MI
enlarged R wave
ventricular hypertrophy
cardiac cycle
atria and ventricles contract alternately
blood flows from areas of high pressure to low pressure
complete cycle includes systole and diastole of atria and ventricles
systole
phase of contraction
diastole
phase of relaxation
blood pressure
systolic/diastolic
pulse pressure
systolic - diastolic
cardiac muscle contraction
- rapid depolarization due to opening of Na+ channels
- plateau due to opening of Ca++ channels
- repolarization due to opening K+ channels
- refractory period; longer than contraction
relaxation (quiescent) period
early ventricular diastole (0.4s)
- follows t-wave
- ventricular pressure drops
- SL valves close
- brief isovolumetric relaxation
- when ventricular pressure drops below atrial, AV valves open
ventricular filling
mid-late ventricular diastole (0.1s)
- rapid ventricular filling after AV valves open
- SA node fires (P wave), atria contract filling ventricles
- atria relax, ventricles depolarize (QRS)
ventricular systole
- impulse passes through AV node to ventricles
- ventricles contract
- ventricular pressure increases rapidly
- AV valves close (lubb)
- lasts 0.3s
isovolumetric contraction phase
start of contraction to SL valve opening = 0.05s
ventricular ejection phase
opening of SL valves to closing SL valves
phase: ventricular contraction (systole)
blood flow: ventricles into arteries
valves: SL open, AV closed
pressure: V high
phase: atrial relaxation (diastole)
blood flow: atria fill
valves: SL open, AV closed
pressure: A low, but rises
phase: ventricular relaxation (diastole)
blood flow: ventricles fill
valves: AV open, SL closed
pressure: V low, but rises
phase:
blood flow: atria to ventricles
valves: AV open, SL closed
pressure: A high
lubb
S1: closing of AV valves (ventricular systole); loud and long
mitral stenosis: diastolic
dupp
S2: closing of SL valves (ventricular diastole); short and sharp
aortic stenosis: systolic
murmur
incomplete closing of valve cusps
cardiac output (CO)
volume of blood pumped by each ventricle in one minute; average is 5L; HR x SV
stroke volume (SV)
volume of blood pumped out by a ventricle with each beat (EDV - ESV); average is 50-70mL
end diastolic volume (EDV)
average is 120-150mL
end systolic volume (ESV)
average is 50-60mL
blood pressure (BP)
the pressure exerted by blood on the wall of arterioles
mean (systemic) arterial blood pressure (MABP)
Maximum during systole, minimum during diastole
normal range is 120/80
CO x TPR
total pressure resistance (TPR)
pressure within arterioles
CV regulation: autonomic nervous system
located in medulla of brainstem
parasympathetic (normal) decreases (CN X, vagus)
sympathetic (stress) increases (white rami communicates)
CV regulation: chemicals
hormones (epinephrine increases rate and force)
ions (calcium increases, potassium, sodium decreases)
atrial natriuretic peptide (ANP)
CV regulation
decreases with age females higher, males lower temperature (heat increases) emotion disease
chronotropic
rate of contraction
inotropic
force of contraction
baroreceptors
aortic/carotid sinuses
increase in BP, vasodilation, decrease heart rate
decrease in BP, vasoconstriction, increase heart rate
chemoreceptors
aortic/carotid bodies
detects changes in pH, temperature, ions, and hormones
artery
- strong, thick-walled
- carry blood under great pressure
- carry blood that is high in oxygen, low in CO2 (except pulmonary)
- branch into arterioles
- may unite with branches of other arteries supplying the same region forming anastomosis
hemodynamics
study of the forces in blood movement
arteriole
- small artery
- carry blood to capillaries
- regulates blood pressure
vasoconstriction
decreased blood flow, increased blood pressure
vasodilation
increased blood flow; decreased blood pressure
capillary
- smallest, thinnest blood vessels
- permit exchange of gases, nutrients, and wastes between blood and tissues
- endothelium, basement membrane, no tunica media
types of capillaries
continuous
fenestrated
sinusoids
continuous capillary
plasma membranes form continuous ring around lumen
found in skeletal/smooth muscle, CTs, lungs
fenestrated capillary
endothelial plasma membrane contain pores
found in glomeruli of kidneys, villi of small intestine
sinusoids
contain spaces between the endothelial cells with basement membranes being incomplete or absent
found in liver, spleen
capillary exchange
simple passive diffusion
vesicular transport
bulk flow
simple passive diffusion
- most common
- substances include oxygen, CO2, glucose, hormones
- lipid soluble pass directly through endothelial cell membrane
- water soluble pass through fenestrations between endothelial cells
vesicular transport
formation of a vesicle to move in/out of cell, fuses with cell membrane
bulk flow
filtration, absorption
vein
- carry blood toward heart
- thin walled
- carry blood under low pressure
- contain valves to preven regurgitation
- carry blood high in CO2 (except pulmonary)
venule
carry blood from veins to capillaries
blood distribution
60-70% in veins/venules 10-12% in arteries/arterioles 10-12% in pulmonary vessels 8-10% in heart 4-5% in capillaries
BP factors
- cardiac output
- blood volume
- peripheral resistance
peripheral resistance
opposition to blood flow primarily due to friction
- blood viscosity
- vessel length
- vessel radius
neuro regulation of CV system
- medulla
- three centers: higher brain centers, baroreceptors, chemoreceptors
- from CV center to SA node; vasomotor center to smooth muscle of peripheral vessels
negative feedback high BP
- BP increase detected by baroreceptors in carotid or aorta
- Impulse sent to CV & vasomotor centers
- CV center sends impulse to SA node to decrease HR, lowering CO/BP
- vasomotor center sends an impulse the arterioles causing vasodilation, lowering BP
hormones that increase BP
1, epinephrine, norepinephrine (increases CO, vasoconstriction)
- antidiuretic hormone (increases reabsorption of H2O by collecting ducts in kidneys, vasoconstriction)
- angiotensin II (vasoconstriction, secretion of aldosterone)
- aldosterone (increases Na+, water reabsorption in DCT
hormones that decrease BP
- atrial natriuretic peptide (vasodilation, loss of salt/water in urine)
- histamine (vasodilation)
pulse
- pressure wave that travels through arteries following ventricular systole
- strongest in arteries closest to heart
- commonly measured in radial artery
- normal is 70-80bpm
tachycardia
pulse > 100bpm
bradycardia
pulse < 60bpm
sphygmomanometer
instrument used to measure BP; typically use brachial artery
pulmonary circuit
vessels that carry blood the right ventricle to the lungs, and vessels that return the blood to the left atrium
- pulmonary trunk
- R&L pulmonary arteries
- capillaries in lungs
- R&L pulmonary veins
top CV diseases
- ischemic heart disease
- hypertension
- congenital septal defects
ischemic heart disease
primary cause is atherosclerosis within vessels restricting blood flow; coronary artery disease
congenital septal defects
acyanotic: ventricular/atrial septal defect
cyanotic: tetralogy of Fallow; transposition of great vessels
tetralogy of Fallow
dextraposed aorta -> pulmonary stenosis -> right ventricular hypertrophy -> blood leaks R->L ventricle
transposition of great vessels
pulmonary trunk & aorta switched; often accompanied by septal defects
circle of willis
sits around sella turcica; blood-brain barrier
left and right internal carotid (also from middle cerebral)
left and right anterior cerebral
anterior communicating
left and right posterior cerebral (from basilar
pulse deficit
difference between cardiac contractions vs. pulse; normal is below 10.
branches of the aorta
ascending aorta
aortic arch
descending aorta
branches of the ascending aorta
right coronary (myocardium) left coronary (myocardium)
branches of the aortic arch
brachiocephalic (right arm/head)
left subclavian (left arm)
left common carotid (left head)
branches of the common carotid arteries
internal common carotid (brain)
external common carotid (scalp)
branches of the subclavian arteries
axillary (armpit)
vertebral (cervical vertebrae/skull)
vertebral arteries
anastomose into basilar artery
branches of axillary arteries
becomes brachial distally (upper arm)
radial (lateral forearm)
ulnar (medial forearm)
descending aorta
becomes thoracic within thoracic cavity
becomes abdominal within abdominal cavity
branches of abdominal aorta
celiac trunk (liver, stomach, spleen)
superior mesenteric (sm intestine, cecum, ascending/transverse colon, pancreas)
inferior mesenteric (descending/sigmoid colon, rectum)
suprarenal & renal
gonadal
common iliac
common iliac arteries
becomes external iliac within pelvis (lower extremities)
becomes femoral in leg (thigh)
becomes popliteal in knee
branches of popliteal arteries
posterior tibial (lower leg) anterior tibial (foot/toes)
superior vena cava
right & left brachiocephalic
branches of brachiocephalic veins
jugular (branches into internal and external)
subclavian
branches of subclavian veins
cephalic
axillary
branches of axillary veins
basilic
brachial
median cubital vein
anastomose with basilic & cephalic veins
common venipuncture site
coronary sinus
drains directly into right atrium
inferior vena cava
hepatic
renal & suprarenal
gonadal
common iliac
hepatic vein
becomes hepatic portal vein
branches: gastric, mesenteric, splenic
common iliac vein
internal
external
external iliac vein
femoral great saphenous (longest vein, begins median ankle)
atrial natriuretic peptide
- increased blood pressure/volume
- stretched atrial walls
- ANP released
- stimulates water/Na+ release, inhibits aldosterone, surpasses thirst, dilates blood vessels
- increased fluid loss, reduced fluid gain, reduced blood pressure
hydrostatic pressure (HP)
force generated by pressure on capillary wall
oncotic (colloid osmotic) pressure (OP)
force exerted by proteins (albumin) present in blood or interstitial fluid on capillary walls
HP > OP
fluid forced out of capillary (24L/day)
HP < OP
fluid reabsorbed into capillary (20.4L/day)
lymphatic capillaries
absorb remaining fluids (3.6L/day)
net filtration pressure
difference between hydrostatic and oncotic pressure
total capillary net filtration pressure
CH - capillary hydrostatic pressure CO - capillary oncotic pressure IH - interstitial hydrostatic pressure IO - interstitial oncotic pressure (CH + IO) - (CO + IH)
