Anatomy chapter 17
how much does the heart weigh
250 to 350 grams
The amount of blood remaining in each ventricle at the end of the ventricular ejection phase is normally about
50 ml
Calculate cardiac output if the heart rate is 85 beats/minute, end-diastolic volume (EDV) is 130 ml, and end-systolic volume (ESV) is 60 ml
5950
How much blood is pumped from each ventricle during the ventricular ejection phase?
70 ml
atria of the heart produces a hormone called?
ANP -this increases the release of water and sodium into the urine which decreases BV which decreases BP
receives the wave of depolarization
AV node then AV bundle then right and left bundle branches then conduction myofibers (causes contraction)
On an electrocardiogram (ECG), atrial repolarization is obscured by the
QRS wave
Which part of the electrocardiogram (ECG) would most be affected by abnormally slow depolarization of the ventricles?
QRS wave
heard when AV valves close
S1 "lub"
the pacemaker of the heart
SA node causes 60-80
What activity is occurring in the heart during the Q-T interval on an electrocardiogram (ECG)?
The ventricular cells are undergoing action potentials
The force that right and left ventricles must overcome in order to eject blood into their respective arteries
afterload
when more than one artery supplies an area of the body w a blood supply or more than 1 vein drains an area of the body of blood
anastomoses (when blood flows thro this alternate route it is called collateral circulation)
chest pain
angina
Which vessel supplies the systemic circuit with oxygenated blood?
aorta
___ is the major systemic artery
aorta
___ of the heart sits in the cardiac notch of the left lung (bottom of heart)
apex
take blood away from the heart
arteries
shallow groove found between the atria and ventricles
atrioventricular sulcus
flat top of the heart
base
How do cardiac cells sustain a membrane potential of around 0 mV during the long plateau phase?
calcium channels remain open
pacemaker cells travel quickly thro the heart by ____
cardiac conduction system -electrical synapses (gap junctions) (FAST!)
CO= HR x SV
cardiac output equation
factors that influence HR
chronotropic agents
myocytes (cardiac muscle cells) are arranged in a ___ pattern
circular
balloon is inflated in blocked artery and a stent to keep it open
coronary angioplasty
what is the leading cause of death?
coronary artery disease
bc of how thick the heart is, it is composed of it's own BV's called
coronary circulation
fibrous skeleton (acts as electrical insulator) is composed of ___
dense irreg CT
-hole located between the pulmonary trunk and aorta -allows blood to flow directly from the pulmonary trunk to the aorta bypassing the lungs -closes after birth and becomes the ligamentum arteriosum
ductus arteriosis
-hole in fetal circulation that allows the blood to bypass the hepatic portal vein and the liver and go directly into the inferior vena cava - after birth the ductus venosus collapses and becomes ligamentum venosum
ductus venosus
innermost layer of the heart -composed of simple squamous epithelium called endothelium
endocardium
what is the outer layer of the heart?
fibrous pericardium (resists stretching and helps prevent overfilling) (anchors the heart to structures)
what are the 4 phases of the heart cycle
filling, contraction, ejection, and relaxation
-hole located in the interarterial septum -allows blood to flow directly from the right atrium to left atrium bypassing the lungs -closes after birth and becomes the fossa ovalis
foramen ovale
increased ventricular muscle cells stretch, leads to more forceful contraction
frank starling law
left ventricular hypertrophy results from
high BP in systemic circuit
thyroid hormones and glucagon
increase HR
agents that affect contractility
inotropic agents
valve fails to close fully which allows blood to leak back
insufficient valve (heart murmur)
What surface groove separates the right and left ventricles?
interventricular sulcus
a shallow groove found between the right and left ventricles
interventricular sulcus
An insufficient mitral valve (bicuspid valve, or left atrioventricular valve) would allow the backflow of blood into the
left atrium
The heart is situated in the middle of the thoracic cavity in a region known as the
mediastinum
___ is the thickest layer of the heart
myocardium
protein that carries oxygen
myoglobin
in between parietal and visceral pericardium
pericardial cavity (has fluid)
Contains fetal capillaries and maternal capillaries to aid in diffusion of O2, CO2, nutrients, waste between fetal and maternal capillaries without blood exchange
placenta
The length or degree of stretch of sarcomeres in ventricular cells before they contract
preload
____ circuit runs from the right side of the heart
pulmonary
right ventricular hypertrophy results from
respiratory disease or high BP in pulmonary circuit
heard when semilunar valves close
s2
prevents backflow from the major arteries into the ventricles
semilunar valves
inner layer of the heart that provides serous fluid -fused to pericardium -attached to the heart under visceral pericardium are fat deposits
serous pericardium parietal pericardium visceral pericardium or epicardium
calcium deposits have built up which makes valves hard and inflexible which narrows the opening of the valve -heart has to pump harder
stenotic valve (heart murmur)
cardiac muscle tissue have ___ -branched cells w a single nucleus -shorter and wider
striations
____ is the major systemic vein
superior and inferior vena cava
___ circuit runs from the left side of the heart
systemic
Archie has a resting heart rate of 125 beats per minute. Classify his cardiac dysrhythmia
tachycardia
Afterload is described as
the force the ventricles must overcome to eject blood into their respective arteries
What produces the "lub dub" heart sounds?
the vibrations of the ventricular and blood vessel walls when valves shut
mitral and aortic valves are most commonly affected by murmurs
true
norepinephrine increases HR
true
parasympathetic NS decreases HR by acetylcholine -adrenal medulla secretes the hormones
true
the left ventricle is the thickest
true
-Blood vessels to transfer blood between placenta and fetus - Umbilical vein transports oxygenated blood from placenta to the liver of the fetus - 2 Umbilical arteries transport deoxygenated blood from internal iliac arteries of the fetus to placenta
umbilical cord
return blood to the heart
veins
During what phase does blood flow from the ventricles into the pulmonary trunk and aorta?
ventricular ejection phase