ch 2 - the heart

found in the ____ cavity in a space called the ____. covered by the _____ (tissue) and sits in the ______ cavity.

[thoracic cavity] [mediastinum]

[pericardium] [pericardial cavity]

pericardial cavity

serous fluid filled cavity - located btwn visceral and parietal pericardium

most BVs emerge and enter through the ____. the most inferior tip of the heart is the _____

[base] [apex]

name the 4 chambers of the heart

atria (upper receiving chambers)

• right atrium

• left atrium

ventricles (lower pumping chambers)

• right ventricle

• left ventricle

auricles

external muscular pouches increasing atria volume

list the 2 circulation system types in the human body

1. pulmonary

2. systemic

pulmonary circulation

transports deoxygenated blood from the heart to the lungs for O2 absorption, CO2 release

systemic circulation

carries oxygenated blood from heart to all body tissues to deliver nutrients, collect waste

why does pulmonary circulation send deoxygenated blood to the lungs if it’s deoxygenated? don’t the lungs breathe in oxygen?

we are talking about blood flow, not the actual gas of O2 inhaled into the lungs. deoxygenated blood undergoes gas exchange when it is sent to the lungs (aka CO2 is dropped off and fresh O2 is absorbed).

the fresh O2 travels back to the heart through the pulmonary veins (systemic circulation) and is then sent out to body tissues

what part of the heart pumps blood into the following:

• pulmonary circulation circuit

• systemic circulation circuit

• pulmonary = right ventricle (pumping chamber)

• systemic: left ventricle (pumping chamber)

describe the flow of blood intro, through, and out of the heart during the pulmonary circulation circuit (specific structure names)

1. deoxygenated blood enters heart through superior and inferior venae cavae

2. blood drains into the right atrium

3. blood pumps into the right ventricle

4. from there, blood travels through the pulmonary semilunar valve to the pulmonary trunk (superior structure)

5. from pulmonary trunk, blood travels through L+R pulmonary arteries

6. blood travels to lungs where pulmonary capillaries exhibit gas exchange (CO2 → O2)

describe the flow of blood intro, through, and out of the heart during the systemic circulation circuit (specific structure names)

1. after travelling to the lungs to pick up O2, oxygenated blood travels back to the heart

2. blood returns into the heart through the L+R pulmonary veins

3. blood drains into the left atrium

4. blood is pumped into the left ventricle

5. blood is pumped through the aortic semilunar valve into the aorta

6. aorta branches out allowing blood to travel to body tissues

7. systemic capillaries exhibit gas exchange (O2 → CO2)

label all structures within the figure

membrane surrounding heart and the pericardial cavity

pericardium

pericardium (where + 2 layers + sublayers)

• also define pericardial cavity

membrane surrounding heart and its pericardial cavity

2 layers

• outer: fibrous pericardium

• inner: serous pericardium

  • parietal layer: fused to fibrous pericardium

  • visceral layer: physically part of heart wall

pericardial cavity

• serous-fluid filled space inbtwn visceral and parietal pericardium

identify the membrane layers of the heart

identify the 3 layers of the heart (NOT the serous/fibrous membranes)

• epicardium

• myocardium

• endocardium

epicardium

(1/3 heart layers)

• visceral pericardium

myocardium (thick/thin layer, cell type, unique function, septa)

(2/3 heart layers)

• thickest layer of hearty

• cardiac muscle cells

• cardiac muscle tissue contracts to pump blood through the heart

endocardium (thick/thin layer, cell type, septa)

(3/3 heart layers)

• innermost layer, thinnest layer

• simple squamous epithelium - endothelium

the myocardium surrounding the ______ ventricle is thicker so it can generate large pressure amounts, overcoming the […]

[left ventricle] - [greater resistance in the systemic circuit]

septa (3) (other internal structures of heart)

extension of myocardium that divides heart into its 4 chambers

1. separating atria: interatrial septum

2. separating ventricles: interventricular septum

3. separating atria from ventricles: atrioventricular septum

   1. thicker

   2. reinforced with cardiac skeleton (dense connective tissue)

fossa ovalis (other internal structures of heart)

oval depression in the interatrial septum (septum separating the 2 atria) - leftover from foramen ovale (opening in fetal heart)

valves (2) (other internal structures of heart)

• openings btwn atria and ventricles: atrioventricular valves

• openings btwn ventricles and arteries (leading to aorta and pulmonary arteries): semilunar valves (pulmonary, aortic)

purpose of having valves

ensures unidirectional flow of blood; no backflow

coronary sinus (other internal structures of heart)

vein draining blood from the heart myocardium

autorhythmicity

cardiac muscle initiating action potentials that spread rapidly from cell to cell

contractile cells

conduct impulses and perform contractions to pump blood

conducting cells

initiate and propagate action potential to trigger contractions

sinoatrial (SA) node

pacemaker setting normal heart rhythm

• generates nerve impulse initiating sinus rhythm → sends impulse to atrioventricar node

atrioventricular (AV) node

electrocardiogram (ECG)

tracing the electrical signal of the heart using electrodes (3, 5, 12)

5 points of the ECG

1. P Wave = atrial depolarization, contraction begins

2. QRS Complex = ventricular depolarization, contraction begins at R wave

3. T Wave = repolarization of the ventricles (atria repolarize during QRS wave)

systole

period where blood is pumping out of the heart

diastole

relaxation period where heart chambers fill with blood

S1 vs S2

S1 = atrioventricular valves