Cardiac Physiology

A system comprising the heart, blood, and blood vessels.

Cardiovascular System

Fluid that carries materials to and from cells.

Blood

the pump that pumps blood throughout the body

the heart

series of tubes that transport blood

blood vessels

Red blood cells that carry oxygen bound to hemoglobin.

Erythrocytes

White blood cells that mediate immune responses (fight disease)

Leukocytes

Parts of cells (cell fragments) called megakaryocytes, that allow your blood to clot. 

Platelets

The liquid portion of blood.

Plasma

Large blood vessels that carry blood away from the heart. (moves fast)

Arteries

Smaller blood vessels that carry blood away from the heart and leads to your capillaries (moves fast)

Arterioles

Large blood vessels that carry blood back to the heart (fast flow)

Veins

Small blood vessels that carry blood to the heart & collects blood from the capillaries

• Venules

The smallest blood vessels where gas exchange occurs, carries blood away from the heart, and blood moves slowly through here (leaky)

Capillaries

wider diameter =

faster blood flow

The muscular wall separating the left and right sides of the heart.

Septum

Includes the left atrium and left ventricle; supplies blood to the systemic circuit (the rest of your body).

Left side of heart 

Blood rich in oxygen, delivered from the lungs to the heart.

Oxygenated Blood

Includes the right atrium and right ventricle; supplies blood to the pulmonary circuit. (lungs)

Right Heart

Blood low in oxygen but high in CO2, returned from the tissues back to the heart (just left the lungs): comes out the tissues to go to the heart

Deoxygenated Blood (blue)

what kind of blood is pumped through the right side of the heart to the lungs?

deoxygenated blood

what kind of blood is pumped through the left side of the heart to everywhere else in the body?

oxygenated blood (red)

A duct that connects the aorta and pulmonary artery in embryonic development that normally closes after birth.

Ductus Arteriosus

A condition where the ductus arteriosus does not close after birth, leading to mixed oxygenated and deoxygenated blood.

Patent (open) Ductus Arteriosus (PDA)

Shortness of Breath, stunted growth ,and can lead to congestive heart failure later in life. 

symptoms of PDA due to mixed blood.

Blood vessels in the lungs and connecting lungs to the heart.

Pulmonary Circuit

Blood vessels in the rest of the body.

Systemic Circuit

what part of the heart is the most muscular and has to pump blood all the way to your toes?

left ventricle

what do valves do?

prevents the back flow of blood which allows for unidirectional flow

separates the atria and ventricles. prevents blood from leaving the ventricles and going back into the atria and separates the two

Atrio-ventricular Valves (AV)

The left AV valve that seperates the left atrium and left ventricle.

Mitral/Bicuspid Valve

The right AV valve that separates the right atrium from the right ventricle 

Tricuspid Valve

Valves that prevent blood from leaving the arteries and going back into the ventricles (separates arteries and ventricle).

Semilunar Valves (SL moon valves)

The left SL valve that prevents backflow into the left ventricle.

Aortic Semilunar Valve

The right SL valve that prevents backflow into the right ventricle.

Pulmonary Semilunar Valve

Ways to increase pressure in the heart?

Contraction & Adding more blood

What direction does blood move?

from high to low pressure

AV valves _____ when atrial pressure > ventricular pressure

open

SL valves ___ when ventricular pressure > aortic/arterial pressure.

open

AV valves _____ when ventricular pressure > atrial pressure

close

SL valves ____ when aortic/arterial pressure > ventricular pressure.

close

what is the order of the Contraction of Myocardium (cardiac cycle)

First: Both atria contract at the same time, Second: Both ventricles contract at the same time 

When the heart contracts without neural input it is ____

Myogenic

Sets the rhythm/how quickly the heart beats using SA & AV nodes

Pacemaker Cells

Cells and that generate the force/ how hard the heart beats during heart contraction.

Cardiac Contractile (muscle) Cells

Transmits the rhythm of the heartbeat through electrical activity (internodal pathway, interatrial pathway, Purkinje fibers)

Conduction fibers (Cardiac)

 Like the electrical wiring in the heart it allow the action potentials that were produced by the SA node and AV node to flow throughout the heart.

Conduction fibers

Located in the right atrium & produces an action potential that makes both atria contract 

SA Node

What is at the top of the ventricles and produces a second action potential that makes both ventricles contract

AV Node

A rapid rise and subsequent fall in the voltage or membrane potential across a cellular membrane.

Action Potential

Connections between cardiac muscle cells that allow synchronized electrical activity between cells in a specific order

Gap Junctions

The nerve from the heart enters the spinal cord next to the left arm nerve. Pain signals from the heart can “spill over,” making the brain think pain is coming from the arm. This is called referred pain and is a heart attack symptom.

. Why Heart Pain Affects the Left Arm

when the cell becomes less negative

depolarization

Do not have a stable resting membrane potential

and

Constantly depolarize → repolarize → hyperpolarize.

Pacemaker cell action potential

Cardiac pacemaker cells spontaneously depolarize because of the activity of ? because of these ___, one action potential inevitably leads to the next action potential. 

HCN: “funny” channels

what is activated by hyperpolarization of the membrane?

HCN channels: Funny channels

what happens during slow depolarization?

Voltage-gated K channels close

“Funny” channels (let Na in, K out) open

PNa↑   PK↓

ALL valves are closed: volume of blood remains the same.

Isovolumetric Contraction

Phase of the cardiac cycle where the atria contract to push blood into the ventricles.

Atrial Contraction

Phase where blood is ejected from the ventricles into the systemic and pulmonary circuits.

Ventricular Ejection

Phase during ventricular relaxation where all heart valves are closed.

Isovolumetric Relaxation

Occurs during ventricular contraction, prompting closure of AV valves.

Rising Pressure in Ventricles

The phase of the cardiac cycle in which the ventricles relaxes and fills with blood. (when you die your body relaxes)

Diastole

The phase of the cardiac cycle in which the ventricles contracts and pumps blood.

Systole

Longer in cardiac muscle to prevent tetanus.

Cardiac Action Potential Duration

Mechanism by which calcium entering the cardiac cells triggers more calcium release from the sarcoplasmic reticulum.

Calcium Induced Calcium Release

Calcium channels that open briefly before the threshold to finish depolarizing

T-type Ca Channels

During rapid depolarization, Long-lasting calcium channels. Voltage-gated L-type Ca channels open

Voltage-gated Na channels open

PCa↑↑   PNa↑

L-type Ca Channels

Voltage-gated K channels open

Voltage-gated L-type Ca channels close

Voltage-gated Na channels inactivate

repolarization

Long refractory period makes summation/tetanus of contraction impossible.

Due to L-type Ca2+ channels closing slowly during the falling phase of the action potential.

true

A short delay after both atria/atriums contract to allow enough time for the ventricles to fill up COMPLETELY before they start contracting. 

AV Node Delay

An increase in the membrane potential of a cell, is when it’s getting more negative

Hyperpolarization