Week #6 Cardiovascular System

Location of Heart

Sits in thorax between the lungs

base points toward the right shoulder, while the apex rests on the diaphram pointing left

Three Heart Layers

Epicardium: Protective outer layer

Myocardium: Thick middle layer that contracts to pump blood

Endocardium: Smooth inner lining of the chambers and valves

Four Chambers

Right Atrium: Receives oxygen-poor (deoxygenated) blood from the body through the superior vena cava and inferior vena cava

Left Atrium: Receives oxygen-rich blood from the lungs via the pulmonary veins

Right Ventricle: Receives blood from the right atrium and pumps it to the lungs via the pulmonary artery.

Left Ventricle: the thickest and strongest chamber; it pumps oxygen-rich blood out to the rest of the body through the aorta

Pulmonary circulation

Heart →lung → heart

pulmonary circuit to the systemic circuit

compare action potentials of a neuron vs a cardiac contractile cell

A neuron action potential lasts 1 millisecond and relies on sodium and potassium for rapid communication.

A cardiac contractile cell action potential lasts 200–400 milliseconds, relies on sodium, potassium, and calcium, and features a unique plateau phase that allows the heart muscle to firmly squeeze and safely refill with blood.

describe mechanism of pacemaker cells

spontaneously and continuously drift upward to fire electrical signals that set your heart rate

describe and explain the electrical activity of the heart

an automated system of specialized cells that generate and pass signals to make the heart muscle contract and pump blood

describe and explain the pacemaker activity of the heart

the ability of specialized cells in the sinoatrial (SA) node to spontaneously generate electrical impulses that drive the heartbeat

explain the blood circulation in heart

in a continuous, one-way path divided into the right side (which handles deoxygenated blood) and the left side (which handles oxygenated blood

explain heart sounds

the noises made by blood flowing through the heart chambers and the snapping shut of the heart valves

AV heart closure 1st sound

Semilunar valve closure 2nd sound

explain wiggers diagram

a standard multi-line graph used in physiology to show all the simultaneous electrical, mechanical, and auditory events of a single cardiac cycle (heartbeat)

explain the frank-starling law of the heart

the stroke volume of the heart increases in response to an increase in the volume of blood filling the heart (end-diastolic volume), due to the stretching of cardiac muscle fibers

describe and explain the actions of autonomic nervous system on the heart

autonomic nervous system (ANS) controls your heart rate, pumping strength, and electrical speed without you needing to think about it

It uses two opposing teams to keep your body balanced: the sympathetic nervous system (the accelerator) and the parasympathetic nervous system (the brakes).