TEST 3 material A & P II

cardiovascular system

cardiovascular system

a series of tubes filled with blood connected to a pump

systole

contraction of heart muscle

diastole

relaxation

Blood Pressure

systolic/ diastolic

septum

central wall that splits ventricle into left and right

right half

deoxygenated blood

left half

oxygenated blood

atrium

receives blood returning to the heart

pulmonary artery

only artery that contains deoxygenated blood

pulmonary vein

only vein that carries oxygenated blood

all arteries carry blood..

away from the heart

all veins carry blood..

towards the heart

apex

angles down to the left side of the heart

base

lies behind the system

systemic circulation

left side pumps blood to everywhere but the lungs

aorta→ arteries→ arterioles→ (O2 poor) capillaries → (O2 rich) venules → veins → vena cava → right atrium

pulmonary circulation

right ventricle → pulmonary trunk/ arteries (O2 poor) → capillaries → (O2 rich) pulmonary veins → left atrium

parietal pericardium

fits loosely aroundd heart

visceral pericardium

this superficial layer of heart

pericardial cavity

filled with pericardial fluid for friction-free environment

heart wall; 3 types of tissue

heart/ cardiac muscle: myocardium

epicardium: visceral layer of pericardium

endocardium: inside

cardiac muscle is

-rich in myoglobin and glycogen

-huge mitochondria: fills 25% of cell

organic fuels used

-fatty acids (60%)

-glucose (35%)

-ketones, lactic acid and amino acids (5%)

4 types of heart valves

2 atrial ventricular: between atria and ventricles

2 semilunar valves: between ventricles and arteries

right AV has how many flaps?

3

left AV has how many flaps?

2

lub

first heart sound; closing of the AV valves

dup

2nd heart sound; closing of the semilunar valves

chordae tendinae

collagenous tendon

prolapse

something is sitting where it isn’t supposed to

“working” cardiac / “conducting” myocytes

right atrium → tricuspid valve → right ventricles → pulmonary valve → pulmonary trunk → right and left pulmonary veins → right and left lungs → right and left pulmonary veins → left atrium → bicuspid/ mitral valve → left ventricle → aortic valve → aorta → systemic circulation

where are the autorythmic myoctes located?

SA and AV nodes

autorythmic

-spontaneously generate AP every .8 seconds

-1% of myocytes found in SA and AV

-incapable of contrition (dont have actin or myosin)

-resting membrane potential= -60mV (unstable)

contractile

-contract in response to AP in autorythmic cells

-make up whole heart expect AV/ SA nodes

-alot of mitochondria and myoglobin

-resting membrane potential = -90mv (stable)

what is needed for muscle contraction

Ca

gap junction

found in intercalated discs. pores that allow ions to travel from 1 cell to another (Na+)

desmoses

allow tension generated in one cell to the adjacent cells; protein complexes electrical event (AP) spread and are followed by contraction

thin filament

actin

thick filament

myosin

troponin C

binds to calcium

when calcium binds to troponin c…

tropomyosin changes its shape and exposes myosin binding sites on actin.

actin bind to myosin → contraction

key facts to contraction

• amount of Ca in the cytosol during contraction

• length of the fiber before contraction

contraction

• from SA node, atria contracts, causing atrial systole

• only route for AP to spread wave of depolarization

• from the SA node, the AP propagates via gap junctions through contractile cells causing atrial systole

ventricular systole

AV node to the bundle of His, speed AP to the purkinje fibers, that wraps around ventricles causing ventricular systole

electorcardiogram

graphical representation of the summation of the APs in the heart

P wave

atrial depolarization

QRS wave

atrial depolarization , occurs but is hidden by a much larger ventricular depolarization

T wave

depolarization of both ventricles

5 phases of the cardiac cycle

• passive ventricular filling

• atrial systole

• isovolumetic contraction

• ventricular ejection

• isovolumetric relaxation

end diastolic volume

volume of blood after filling phase

stroke volume

amont of blood which leaves each ventricle per beat

cardiac output

amount of blood which is pumped out of each ventricle per minute ml/ min

end systolic volume

blood remaining in ventricle

cardiac output formula

HR x SV

strove volume formula

pp x 1.75

pulse pressure

systolic pressure- diastolic pressure

caridacceletory

sympathetic center in medulla oblongata can increase heart rate and stroke volume

cardioinhibitory

parasympathetic; only in the medullar oblongata, can decrease heart rate only

sympathetic

NE, EPI receptors; adrenergic reptors

2 types: alpha receptors located in the blood vessels

beta receptors located in the SA and AV nodes

parasympathetic

ACH receptors cholinergic resptors

ACH at SA node; decrease frequency of. ap, decrease heart rate

passive ventricular filling

-blood returning to atria pushes open the AV valves and blood enters ventricles

85% of ventricular blood

atrial systole

-contract atria, add 15% of ventricular blood. end of filling phase; end diastolic volume

isovolumetric contraction

pressure builds in the ventricles as contraction begins. pushes blood against bottom side of AV valves.AV valves close ( 1st heart sound)

ventricular ejection

continued contraction of the ventricles pushes open semilunar valves. blood enters the great arteries. the volume of blood ejected from each ventricle is known as the stroke volume (ml/ beat)

isovolumetric relaxation

-ventricular muscle relaxes blood in the arteries relaxes back and closes the semilunar valves. second heat sound. amount of blood left in ventricles after systole is known as the end systolic volume

regulation of stroke volume

• ventricular contractility

• the preload of the ventricles

• the after load of the ventricles

arteries- arterioles

• divergent pattern of blood flow

veins- venules

return blood back to heart/ convergent pattern

capillaries

site of gas exchange

right ventricle

blood is pumped to the lungs and then back to the left atria

left ventricle

blood is pumped at a high pressure to the rest of the body

tunica media

layer of smooth muscle

tunic externa

fibrous layer

cardiac output

total blood flow through any level of circulation

HR x SV

during exercise

increase perfusion of lungs

muscle tone

partially contracted at all times

peiseuilles law

determines how much blood travels through vessels resistance is influenced by; diameter, length, viscosity

locate controls is accomplished by

paracrine

systemic control

occurs by sympathetic innervation