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