BIOL 117 Exam 1

perfusion

delivery of blood per unit time per gram of tissue

arteries

away from heart

veins

toward heart

capillaries

sites of exchange between blood and alveoli

right atrium

receives deoxygenated blood from the body

right ventricle

pumps deoxygenated blood to the lungs

left atrium

receives oxygenated blood from the lungs

left ventricle

pumps oxygenated blood to the body

SVC and IVC

drain deoxygenated blood into the right atrium

pulmonary trunk

receives deoxygenated blood pumped from right ventricle

pulmonary vein

drain oxygenated blood into left ventricle

aorta

receives oxygenated blood pumped from left ventricle

valves

prevent backflow of blood

right AV (tricuspid)

between right atrium and ventricle, closes when ventricles contract and has papillary muscles and tendinous chords

semilunar valves

open when ventricles contract and close when they relax

pulmonary semilunar valve

between right ventricle and pulmonary trunk

left AV (bicuspid or mitral)

between left atrium and left ventricle

aortic semilunar valve

between left ventricle and aorta

right side vs left side of heart

right side receives deoxygenated blood from body and pumps it to the lungs. left side receives oxygenated blood from the lungs and pumps it to the body

pulmonary circulation

deoxygenated blood from right side of heart goes to lungs, blood picks up oxygen and releases carbon dioxide, blood returns to left side of heart

systemic circulation

oxygenated blood from left side of heart goes to the rest of the body and returns to the right side of the heart

basic pattern for circulation

right heart- lungs- left heart- body- right heart

position of the heart

sits posterior to sternum on the left side of the body between the lungs in the mediastinum

base

postero superior surface

apex

inferior, conical end

three layers that enclose heart

fibrous, parietal, visceral

fibrous layer

dense irregular CT that attaches diaphragm and base of aorta to pulmonary trunk to anchor heart and prevent its overfilling

parietal layer

simple squamous epithelium and areolar CT that connects to fibrous pericardium

visceral layer

simple squamous and areolar CT that attaches directly to heart and has two serous layers separated by pericardial cavity

pericardial sac

formed by fibrous pericardium and parietal layer of serous pericardium

anterior features of heart

atriums and ventricles, right auricle, pulmonary trunk, aorta and aortic arch

posterior features of the heart

left atrium and ventricle, pulmonary vein, vena cava, posterior interventricular sulcus, coronary sulcus and coronary sinus

how does the heart wall varies in thickness

the ventricles are thicker and left side is thicker than the right side

epicardium

simple squamous and areolar CT

myocardium

pumps blood

endocardium

simple squamous epithelium and areolar CT that is continuous with the lining of the blood vessels

interatrial septum

separates left atrium from right atrium

interventricular septum

separates left ventricle from right ventricles

pectinate muscles

ridges on anterior wall and within auricle

fossa ovalis

oval depression on interatrial septum and occupies fetal foramen ovale

foramen ovale

shunts blood from right to left atrium in fetal life

entrances for coronary sinus

SVC and IVC

trabeculae carneae

irregular muscular ridges inside ventricle wall

papillary muscles

cone shaped projections extending from internal ventricle wall (right side has two and left side has three)

chordae tendinae/tendinous chords

papillary muscles that anchor thin strands of collagen fibers

fibrous skeleton

dense irregular CT, framework, attachment, electrical insulator that prevents ventricles from contracting at the same time as arteries

coronary circulation

delivers blood to heart

coronary arteries

transport oxygenated blood to heart wall

coronary veins

transport deoxygenated blood away from heart wall toward right atrium

right marginal artery

supplies right heat border

posterior interventricular artery

posterior ventricles

circumflex artery

left atrium and ventricle

anterior interventricular artery

anterior surface of ventricles and most of interventricular septum

arterial anastomoses

connections between vessels allowing blood to arrive by more than one route

coronary veins

drain heart muscle

great cardiac vein

sits in anterior interventricular sulcus

middle cardiac vein

sits in posterior interventricular sulcus

small cardiac vein

sits next to right marginal artery

coronary sinus

sits in posterior aspect of coronary sulcus

describe cardiac muscle cells

house one or two central nuclei, have sarcolemma that invaginate to form t tubules that extend to the sarcoplasmic reticulum, bundles of myofilaments are arranged in sarcomeres

intercalated discs

connect cardiac cells

desmosomes

mechanically join cells with protein filaments

gap junctions

electrically join cells to make each heart chamber a functional unit (syncytium)

metabolism of cardiac muscle

involves myoglobin and creatine kinase and relies on aerobic cellular respiration, very versatile and uses fatty acids, glucose, lactate, amino acids and ketone bodies

ischemia

low oxygen

conduction system

initiates and conducts electrical events to ensure proper timing of contractions, have action potentials but dont contract and is autonomic nervous system

SA node

initiates heart beat and located high in posterior wall of right atrium

AV node

located in floor of right atrium

AV bundle (bundle of His)

extends from AV node through interventricular septum and divides into right and left bundles

purkinje fibers

extends from left and right bundles at heart apex and courses through walls of ventriclesd

cardiac center of medulla oblongata

cardioinhibitory center, cardioacceleratory center

parasympathetic innervation

comes from the cardioinhibitory center, right vagus nerve innervates SA node, and left vagus nerve innvervates AV node

sympathetic innervation

comes from the cardioacceletory center, increases heart rate and force of contraction and dilates vessels

stimulation of the heart

conduction system initates and propogates action potential and cardiac muscle cells initiate contraction and action potential

resting membrane potential for SA node

-90 mV

pacemaker potential

ability to reach threshold without stimulation

voltage gated channel

slow Na+, fast Ca2+, and K+

autorhythmicity

spontaneous firing

depolarization

impulse from conduction system or gap junctions open fast voltage gated Na2+ channels which causes the RMP to change from -90mV to 30mV

plateau

depolarization open voltage-gated k+ channels and slow voltage gated Ca2+ channels, k+ leaves, sarcoplasmic reticulum releases more Ca2+

repolarization

voltage gated ca2+ channels close while K+ channels remain open and membrane potential goes back to -90mV

refractory period

period of time between impulses which causes tetany in cardiac cells to be impossible

p wave

atrial depolarization

qrs complex

ventricular depolarization

t wave

ventricular repolarization

p-q segment

Associated with atrial cells' plateau (atria are contracting)

s-t segment

associated with ventricular plateau (ventricles are contracting)

p-r interval

atrial depolarization to ventricular depolarization, the time is takes the action potential to transmit the entire conduction system

q-t interval

time of ventricular action potentials

first degree AV block

the R is far from the P

second degree AV block

failure of some atrial action potentials to reach ventricles, PR prolongation and QRS complex is dropped

third degree AV block

failure of all action potentials to reach ventricles

premature ventricular contractions

abnormal action potentials in AV node or ventricles that result from stress, sleep deprivation, or stimulants

atrial fibrillation

chaotic timing of atrial action potentials

ventricular fibrillation

uncoordinated electrical activity in ventricles

ventricular contraction

raises ventricular pressure, AV valves are closed and semilunar valves are open so blood goes to arteries

ventricular relaxation

lowers ventricular pressure, AV valves are open and semilunar valves are closed

EDV

end diastolic volume- volunme of blood in ventricles after diastole which is the maximum blood volume they can hold

isovolumetric contraction

ventricular pressure increases but all valves remain closed because the pressure of the arterial trunk is still higher

ventricular ejection

ventricular pressure exceeds arterial trunk pressure and blood is ejected out through semilunar valves