BMSC 207: Module 10

what are atria?

upper chambers of the heart that receives blood from the blood vessels

what is blood pressure?

the pressure exerted by blood on the walls of the blood vessels. Usually measured in the systemic circuit

what is the electrocardiogram?

a recording of the summed electrical events of the cardiac cycle

What is the Flow (rate)?

the volume of blood that passes one point in the cardiovascular system per unit time

what is a heart valves?

connective tissue valves that prevent the backflow of blood in the heart

what is the pulmonary circuit?

the portion of circulation that carries blood to and from the lungs

what is the systemic circuit?

portion of the circulation that carries blood to and from most tissues of the body

what is the ventricle?

lower chambers of the heart that pump blood out to the body

what is the requirement for a circulatory system?

is a consequence of increasing size and complexity of multicellular organisms

what does the circulatory system provide?

a concentration gradient from the blood to cells for nutrients and in the opposite direction for waste

what is the primary role for the circulatory system?

the distribution of dissolved gases and other molecules for nutrition, growth and repair, while simultaneously removing cellular wastes

what are the three basic functional parts of the circulatory system?

heart, blood, blood vessels

what is the secondary roles for the circulatory system?

- chemical signaling to cells by means of circulating hormones or neurotransmitters

- dissipation of heart by delivering heat from the core to the surface of the body

- mediation of inflammatory and host defense response against invading microorganisms

what were the original thoughts on what the veins and arteries do?

- thought that the veins had its origin in the liver and was distributed throughout the body

- the arteries contained air from the lungs and the 'spirits' which flowed to the heart, distributing heat and life to all parts

what three types is the transport in the circulatory system divided into?

- materials entering the body

- materials moved from cell to cell

- materials leaving the body

what does the heart do?

a dual pump driving blood in two serial circuits

what is the two serial circuits that are apart of the heart?

- pulmonary circuit

- systemic circuit

what carries the blood away from the heart?

arteries

what carries the blood back to the heart?

veins

what are the smallest vessels where transport takes place?

capillaries

what ensures that the blood flows in one direction?

a system of valves in the heart and veins

what are some notable circulations within systemic circuit?

- coronary circuit

- digestive tract/liver portal system

- kidney portal system

where is the blood coming from to the superior vena cava?

blood coming back from upper part of body

where is the blood going too from the right pulmonary arteries?

to right lung

what is the right atrium?

end of systemic circuit (in flow chamber)

what does the right ventricle do?

pumps blood to lungs main pulmonary pump

where is the blood coming from to the inferior vena cava?

blood coming from lower part of body

what is does the aorta do?

- main output for systemic

- carries blood to upper part of body

where does the blood go to the from the left pulmonary arteries?

blood to left lung

what is the left atrium?

main inflow chamber of pulmonary circuit (end of pulmonary circuit)

what is the left ventricle?

- main output pump

- drives bloodflow throughout entire body

what is the septum?

separates the left and right side of heart

where does the descending aorta carry blood too?

to the lower part of the body

where does the right atrium receive and send blood?

- receives blood from the venae cavae

- sends blood to the right ventricle

where does the right ventricle receive and send blood?

- receives blood from the right atrium

- sends blood to the lungs

where does the left atrium receive and send blood to?

- receives blood from pulmonary veins

- sends blood to the left ventricle

where does the left ventricle receive and send blood to?

- receives blood from left atrium

- sends blood to body except for lungs

where does the venae cavae receive and send blood to?

- receives blood from the systemic veins

- sends blood to the right atrium

where does the pulmonary trunk receive and send blood too?

- receives blood from the right ventricle

- send blood to the lungs

where does the pulmonary vein receive and send blood too?

- receives blood from the veins of the lungs

- sends blood to the left atrium

where does the aorta receive and send blood too?

- receives blood from the left ventricle

- sends blood to the systemic arteries

how does blood flow through the cardiovascular system?

liquids and gases commonly flow down pressure gradients from regions of high pressure to region of lower pressure

what creates the initial region of high pressure in the cardiovascular system?

by contraction of the heart

why is pressure lost when blood flows through the vessels?

pressure is lost due to friction created between the blood and vessel walls

what is driving pressure?

the high pressure created in the ventricles

what way does blood flow?

from higher pressure to lower pressure

how is the pressure gradient created?

through contraction of the ventricles

what is the flow of blood in a tube directly proportional to?

the pressure gradient at each end of the tube

True and False. flow is inversely proportional to resistance.

True

what law do you use to predict the resistance to flow from the geometry of the vessel and the properties of the fluid?

Poiseuille's law

with a larger radius is there more or less resistance?

less

what will happen to the resistance and the flow with a shorter length?

there will be less resistance and more flow

what does velocity depend on?

the flow rate an cross-sectional area

what is the heart?

the workhorse of the body, a muscle that continuously contracts, resting only for milliseconds between beats

where is the heart located?

located in the center of the thoracic cavity

what is the pericardium?

- a tough membranous sac that the heart is encased in

- a double walled sac filled with a thin layer of clear pericardial fluid

what does the pericardium do?

lubricated the external surface of the heart as it beats within the sac

what is the heart compose of?

mostly composed of myocardium (cardiac muscle) covered by thin inner and outer layers of epithelium and connective tissue

what does the atrioventricular valves?

allow flow from the atria into the ventricles

How is the AV valve attached to the papillary muscle in each ventricle?

by chordae tendineae (tendon)

what are semilunar valves?

are one way valves that exist between the ventricle and outflow artery

where do cardiac action potentials originates?

in the SA node

what does the backman's bundle do?

conducts action potentials from the SA pacemaker into the left atrium causing contraction

what does the anterior, middle and posterior internodal pathways?

conduct the action potential from the SA node to the AV node, depolarizing right atrial muscle along the way

is the atrial conduction fast or slow?

relatively slow

what prevents conduction directly from atria to ventricle?

layer of connective tissue

why does conduction slow down through the AV node?

to allow blood from atria o empty in to ventricles

what is the ventricular muscles made up of?

a spiral arrangement that ensures blood is squeezed upward from the apex of the heart

what happens if electrical activity cannot be transferred from the atria to ventricles?

complete conduction block

what is complete conduction block caused by?

caused by damage in conduction pathway

what is an example of a complete conduction block?

block at the bundle of his results in a complete dissociation between the atria and ventricles

what does an electrocardiogram (ECG) represent?

the summed electrical activity of all cells recorded from the surface of the body

who modified the ECG as we know it today?

Walter Einthoven

what happens if the electrical activity of the heart is moving towards the positive electrode of the lean?

then an upward deflection is recorded

what happens if electrical activity is moving away from a positive electrode?

is recorded as a downward deflection

what is read when an electrical activity is moving perpendicular to the axis of the electrodes?

it causes no deflection

what do waves appear as on an ECG?

appear as deflections above or below the baseline

what are segments on an ECG?

are the sections of baseline between two waves

what are intervals on an ECG?

are the combination of waves and segments

what do ECGs provide information on?

- on heart rate and rhythm

- conduction velocity