ANA 110 (Salmeron)--University of Kentucky--Exam 1

The heart is a ______

double pump

Left side of heart

pumps blood through miles of blood vessels in body

Right side of heart

- pumps blood to lungs

- can pick up oxygen and unload carbon dioxide

Where is the heart located?

mediastium of thoracic cavity

Apex of heart

directed inferiorly to the left

Base of heart positioned how?

superiorly to the right

Pericardial fluid is between _______ and _______

parietal layer and visceral layer of serous pericardium

fibrous pericardium

- outer layer

- dense irregular connective tissue

- prevents overstretching

serous pericardium

- inner layer of pericardium

- double layer

- delicate

two layers of serous pericardium

parietal and visceral

parietal layer of serous pericardium

fused to fibrous pericardium

visceral layer of serous pericardium

is the outer layer of the heart

Epicardium =

visceral pericardium

Layers of heart wall

epicardium, myocardium, endocardium

Epicardium

- visceral serous pericardium

- contains blood and lymphatic vessels

Myocardium

- middle, cardiac muscle tissue layer

- involuntary

Endocardium

- endothelial layer overlying connective tissue

- lines heart chambers and heart valves

Anatomy of Layers of heart wall

Chambers of the heart

two atria and two ventricles

What do atria do?

superior chambers that receive blood from veins

What do ventricles do?

inferior chambers that pump blood into arteries

Veins

blood to heart

Arteries

blood away from heart

First part of blood flow through heart (flow out)

1. blood to right atrium from superior and inferior vena cavae

2. blood passes right atrioventricular valve to enter right ventricle

3. Blood passes pulmonary semilunar valve

4. enters pulmonary artery which branches into right and left pulmonary arteries

Second part of blood flow though heart (back in)

1. blood returns to left atrium from lungs via pulmonary veins

2. passes left atrioventricular valve (bicuspid) to enter left ventricle

3. blood passes aortic semilunar valve to enter aorta artery

Three branches of aorta

brachiocephalic, left common carotid, left subclavian

Where does the right atrium receive blood?

superior and inferior vena cavae, coronary sinus straight from heart

How is the right atrium separated from the left?

interatrial septum

fossa ovalis

remnant of foramen ovale

pectinate muscles of right atrium

Tricuspid valve anatomy

How does right ventricle receive blood?

from the right atrium

How is the right ventricle separated from the left?

interventricular septum

chordae tendineae

"heart strings"

papillary muscles of ventricles

prevent backflow of blood

Trabeculae carnae

bundles of muscle that force blood out of ventricles

pulmonary semilunar valve anatomy

Circulation of oxygen-poor blood through lungs unloads ______ and picks up ____

CO2, O2

Left Atrium receives blood from where?

the four pulmonary veins

From left atrium, blood passes through the _______ into the _______

bicuspid (left atrioventricular valve), left ventricle

Left ventricle receives blood from where?

left atrium

Ligamentum anteriosum

connects aorta to pulmonary trunk as a remnant of fetal blood shunt

Atrial walls are (thicker/thinner) than ventricular walls

thinner

Why is the left ventricle thicker than the right?

The left ventricle must pump blood throughout the entire body and the right only has to go to the lungs.

Function of heart valves

open and close in response to pressure differences

Blood flows from areas of _____ to _____ pressures

high, low

Atrioventricular valves are between what?

atrium and ventricle

Semi-lunar valves are between what?

ventricle and artery

Tricuspid valve

right AV valve

Bicuspid valve

left AV valve

When heart valves open, what happens?

papillary muscles and chordae tendineae relax

What happens when heart valves close?

papilarry muscles and chordae tendineae are tight

What are the semi-lunar valves?

pulmonary (right) and aortic (left)

Pulmonary circulation

flow of blood from the heart to the lungs and back to the heart

systemic circulation

circulation that supplies blood to all the body except to the lungs

Coronary circulation

flow of blood to and from the tissues of the heart

Systematic circulation is powered by what?

Left ventricle

________ and ______ arteries supply oxygen-rich blood to myocardium of the heart

right, left coronary

Anastomoses

two or more arteries provide alternative routes in case of obstruction

Coronary veins

collect oxygen-poor blood into coronary sinus and empties it into right atrium

Great cardiac veins partners with what?

left anterior descending artery

Middle cardiac vein partners with what?

posterior interventricular artery

Sulci

surface grooves containing coronary blood vessels

Coronary sulcus contains what?

coronary sinus

anterior interventricular sulcus contains what?

Left anterior descending artery and great cardiac vein

posterior interventricular sulcus contains what?

posterior interventricular artery and middle cardiac vein

Intercalated discs

connect muscle fibers

desmosomes in discs provide ______

strength

Gap junctions of heart

connect beats of cells

autorhythmicity

heart beats on its own

sinoatrial (SA) node

pacemaker of the heart

Pattern of automatic depolarization of myocardium

1. SA node--right atrial wall

2. AV node and bundle---interventricular septum

3. right and left bundle branches--toward apex

4. Punkinhe fibers--upward in myocardium

Depolarization

Na+ comes in

Plateau

Ca2+ comes in, triggers contraction

Repolarization

K+ channels open and ions outflow

Long refractory periods between heart beats allows for what?

chambers to refill with blood

heart action potential picture

Thresh hold of SA node action potential

-50mV

Electrocardiogram

recording electrical charges of heartbeats

ECG waves explained

- P wave = depolarization (SA node)

- QRS complex = ventricular depolarization (AV node)

- T wave = ventricular repolarization

Diastole

Relaxation of the heart

Systole

Contraction of the heart

Sequence of systole to diastole

1. P wave

2. atrial systole

3. QRS complex

4. ventricular systole and atrial diastole begin

5. T wave

6. ventricular diastole occurs

Cardiac cycle

all events associated with a single heartbeat

What happens in a single heartbeat?

- two atria systole and diastole

- two ventricles systole and diastole

Heart sounds are caused by what?

closure of the heart valves

Lubb sound (S1)

closure of both AV valves as ventricles contract (ventricular systole)

Dupp sound (S2)

closure of both SL valves as ventricles relax (ventricular diastole)

End Diastolic Volume (EDV)

ventricles are full at end of atrial systole

Wiggers Diagram

different perspectives of cardiac cycle

isovolumetric contraction

all valves are closed

isovolumetric contraction occurs during when?

ventricular systole

ventricular ejection

blood is forced through semi-lunar valves

What happens after ventricular ejection?

end-systolic volume

End Systolic Volume (ESV)

volume of blood remaining in each ventricle after systole

isovolumetric relaxation

AV valves still closed

Isovolumetric relaxation happens when?

A and V diastole of cardiac cycle

Cardiac Output (CO)

Amount of blood pumped in 1 minute (~5 L)

Cardiac output equation

heart rate x stroke volume

Stroke volume

The amount of blood ejected from the heart in one contraction.