Unit 9 - The Concept of Perfusion Flashcards
Essential function of the cardiovascular and pulmonary systems:
- supply _____ _____ to every cell in the body
- _____ in perfusion affects all human functions
- supply oxygenated blood to every cell in the body
- change in perfusion affects all human functions
Where is the heart located
in mediastinum between the vertebral column, sternum; flanked by lungs
What is the pericardium
- heart covering
- anchors heart to surrounding structures to form pericardial sac
3 layers of the heart wall
- epicardium
- myocardium
- endocardium
4 hallow chambers of heart
- 2 atria
- 2 ventricles
- separated by a septum
Right atrium:
- _____ deoxygenated blood from veins of body
- superior vena cava _____ blood from body _____ diaphragm
- inferior vena cava _____ blood from the body _____ diaphragm
- coronary sinus _____ blood from heart
- receives deoxygenated blood from veins of body
- superior vena cava returns blood from body above diaphragm
- inferior vena cava returns blood from the body below diaphragm
- coronary sinus drains blood from heart
Left atrium:
- receives oxygenated blood from lungs through _____ _____
- receives oxygenated blood from lungs through pulmonary veins
Right ventricle:
- receives deoxygenated blood from right atrium and pumps through pulmonary _____ to pulmonary _____ bed for oxygenation
- oxygenated blood travels through pulmonary _____ to left atrium
- receives deoxygenated blood from right atrium and pumps through pulmonary artery to pulmonary capillary bed for oxygenation
- oxygenated blood travels through pulmonary veins to left atrium
Left ventricle:
- _____ blood from left atrium
- pumps blood through _____ to general circulation
- receives blood from left atrium
- pumps blood through aorta to general circulation
atria separated by _____ _____
atrioventricular valves
- Pulmonic valve joins _____ ventricle with pulmonary artery
- aortic valve joins _____ ventricle with aorta
- Pulmonic valve joins right ventricle with pulmonary artery
- aortic valve joins left ventricle with aorta
_____ of valves creates heart sounds
closure
closure of _____ valve produces first heart sound (S1) or “lub”
atrioventricular (AV)
closure of _____ valves produces second heart sound (S2) or “dub”
semilunar
heart sounds associated with contraction and relaxation of the heart:
- systole: ventricular _____
- diastole: ventricular _____
- systole: ventricular contraction
- diastole: ventricular relaxation
There may be additional heart sounds which indicate _____ _____
damaged tissue
Pulmonary circulation:
- _____ side of heart, pulmonary artery pulmonary capillaries pulmonary veins
- _____-pressure system
- right side of heart, pulmonary artery pulmonary capillaries pulmonary veins
- low-pressure system
Systemic circulation:
- _____ side of heart, aorta and branches, capillaries of the brain and peripheral tissues, systemic venous system, and vena cava
- _____-pressure system
- Left side of heart, aorta and branches, capillaries of the brain and peripheral tissues, systemic venous system, and vena cava
- high-pressure system
Coronary circulation:
- _____ that supply the heart muscle itself
- _____ _____ regulated by aortic pressure, heart rate, heart metabolic activity blood vessel tone
- vessels that supply the heart muscle itself
- blood flow regulated by aortic pressure, heart rate, heart metabolic activity blood vessel tone
Transition from fetal to pulmonary circulation:
Flow of blood: placenta -> fetus through _____ _____ to ductus venosus to R atrium
umbilical vein
Transition from fetal to pulmonary circulation:
_____ _____ allows blood flow from R atrium to L, then into L ventricle
Foramen ovale
Transition from fetal to pulmonary circulation:
blood pumped into _____ and systemic circulation
aorta
Transition from fetal to pulmonary circulation:
Systemic vascular resistance:
- _____ after umbilical cord is cut and R atrium pressure falls
- flaps of foramen ovale _____, fibrin deposits seal the opening
- ducuts arteriosus constricts and closes within _____ hours after birth; permanent closure _____-_____ days after birth
increased
close
10-15, 10-21
- one heartbeat of contraction and relaxation stroke - volume
- difference between end-diastolic volume and end-systolic volume
- ranges from 60 to 100 mL/beat, averages 70 mL/beat in an adult
cardiac cycle
- amount of blood pumped by ventricles into pulmonary and systemic circulation in 1 minute
- determined by multiplying stroke volume by heart rate
cardiac output
- percent of diastolic volume ejected from heart during systole
- stroke volume divided by end-diastolic volume
- normal ejection fraction ranges from 50% to 70%
ejection fraction
capability of the heart muscle fibers to shorten
contractility
the greater the volume, the greater the stretch of the cardiac muscle fibers, and the greater the force with which the fibers contract to accomplish emptying
preload-starling’s law
force the ventricles overcome to eject blood volume; pressure in the arterial system ahead of the ventricles
afterload
sinoatrial node (SA node) located at junction of _____ _____ _____ and _____ _____
superior vena cava and R atrium
electrical impulse created by SA node travels to _____ node -> to bundle of his -> to _____ septum -> to _____ fibers in ventricular muscle walls
electrical impulse created by SA node travels to AV node -> to bundle of his -> to interventricular septum -> to purkinje fibers in ventricular muscle walls
electrical stimulus creates an _____ _____ -> exchange of _____, _____, and _____ ions across the cell membrane
electrical stimulus creates an action potential -> exchange of sodium, potassium, and calcium ions across the cell membrane
depolarization causes a _____ _____
myocardial contraction
repolarization is the _____ stage
resting
cardiac output determined by _____ _____
heart rate - direct and indirect autonomic stimulation
heart affected by both direct and indirect _____ _____ _____ stimulation
autonomic nervous system
phase when heart contracts; occurs from two types of ion channels
depolorization
process that returns the cell to a resting state
repolarization
- Movement of ions across cell membrane causes electrical impulse to stimulate muscle contraction
- Produces waveforms on ECG strips
the action potential
- Fast sodium channels—occurs in atrial, ventricular muscle cells and Purkinje conduction system
- Slow calcium channels—occurs in SA and AV nodes
Depolarization—phase when heart contracts; occurs from two types of ion channels
- Refractory period—period of time when myocardial cells resist stimulation; protective mechanism
- Supernormal period—occurs after refractory period; a mild stimulus to the cardiac muscle will cause repolarization
- Many cardiac dysrhythmias triggered during refractory and supernormal periods
Repolarization—process that returns the cell to a resting state
_____ _____ channels—occurs in atrial, ventricular muscle cells and Purkinje conduction system
fast sodium
_____ _____ channels—occurs in SA and AV nodes
slow calcium
period of time when myocardial cells resist stimulation; protective mechanism
refractory period
occurs after refractory period; a mild stimulus to the cardiac muscle will cause repolarization
supernormal period
a wave of blood created by contraction of L ventricle
pulse
pulse located away from the heart
peripheral
a central pulse located at the heart apex; also termed point of maximal impulse or PMI
apical pulse
measure of the pressure exerted by blood as it flows through arteries
blood pressure
Two blood pressure measures
- systolic: ventricles _____
- diastolic: ventricles _____
contract
rest
difference between the diastolic and systolic pressures
pulse pressure
proportion of RBCs to blood plasma
hct
