Ch. 14 Heart and Cardiovascular System

heart

A muscular organ that pumps blood through the circulatory system

Atria

Upper chambers of the heart that receive blood (right atrium from
the body, left atrium from the lungs)

Ventricles

Lower chambers that pump blood (right ventricle to the
lungs, left ventricle to the body)

Valves

Structures that prevent backflow of blood and ensure unidirectional flow

Tricuspid Valve is located

Between the right atrium and right ventricle

Pulmonary Valve is located

Between the right ventricle and pulmonary artery

Mitral (Bicuspid) Valve is located

Between the left atrium and left ventricle

Aortic Valve is located

Between the left ventricle and the aorta

Septum

Muscular wall separating the left and right sides of the heart

Endocardium

Inner lining of the heart

Myocardium

Muscular layer responsible for contraction

Pericardium

Double-walled sac surrounding the heart, protecting and reducing
friction

Arteries

Carry oxygenated blood away from the heart (except the pulmonary artery)

Veins

Carry deoxygenated blood toward the heart (except the pulmonary vein)

Capillaries

Tiny blood vessels where gas, nutrients, and waste exchange occur

Aorta

The largest artery that distributes oxygenated blood to the body

Pulmonary Arteries

Carry deoxygenated blood from the right ventricle to the lungs

Pulmonary Veins

Carry oxygenated blood from the lungs to the left atrium

Vena Cava (Superior & Inferior)

Large veins that return deoxygenated blood to the
right atrium

Coronary Arteries

Supply blood to the heart muscle

Venules

Small veins that collect blood from capillaries

Arterioles

Small arteries that control blood flow into capillaries

Sinoatrial (SA) Node

The heart's primary pacemaker, setting the rhythm at ~70 bpm

Atrioventricular (AV) Node

Delays electrical impulses to allow atrial contraction
before ventricular contraction

Bundle of His

Conducts impulses from the AV node to the ventricles

Right and Left Bundle Branches

Carry impulses down both sides of the
interventricular septum

Purkinje Fibers

Specialized fibers that spread electrical impulses to the ventricles for
contraction

Contractile Cardiomyocytes

striated fibers organized into sarcomeres that perform mechanical contraction to pump blood

where are Pacemaker (Autorhythmic) Cells found

Found in the SA node and AV node

Conducting Cells

Found in the Bundle of His and Purkinje fibers, transmitting
electrical signals

Vascular Endothelial Cells

Line blood vessels, regulate permeability, and control
clotting

Cardiac Endothelial Cells

Line the heart chambers and valves, regulating
myocardial function

where are smooth muscle cells found

walls of arteries and arterioles

what do smooth muscle cells do

regulate vasoconstriction and
vasodilation to control blood pressure

what do fibroblasts do

Responsible for producing extracellular matrix and collagen, playing a role in cardiac structure and repair

what do pericytes do

Support endothelial cells in capillaries and venules, contributing to vascular stability and repair

what do red blood cells do

Carry oxygen throughout the body using hemoglobin

Neutrophils

First responders to infections

Lymphocytes (T & B Cells)

Play a role in immune defense and antibody production

Monocytes/Macrophages

Remove debris and help in immune responses

Eosinophils

Respond to allergic reactions and parasitic infections

Basophils

Release histamines, playing a role in inflammation

what do platelets do

Cell fragments that help in blood clotting by forming platelet plugs at injury sites

what’s the primary function of the cardiovascular system

Transport of nutrients, gases, waste, and chemical signals

what’s the order of the pulmonary circulation

right heart → lungs→ left heart

what’s the order of the systemic circulation

left heart → tissues → right heart

resistance factors increases with

tube length and fluid viscosity

resistance decreases with

larger vessel radius

flow rate =

volume per unit time

velocity =

distance traveled per unit time

myocardium is mostly made of

striated muscle

Coronary Circulation

Supplies blood to the heart muscle

Intercalated Discs contains

gap junctions for rapid electrical conduction

explain what happens during excitation-contraction coupling

Ca2+ influx triggers Ca2+ release from the SR

strength of graded contraction depends on

Ca2+ availability

explain what happens during action potentials

Rapid depolarization (Na⁺ influx), plateau (Ca²⁺ influx),
repolarization (K⁺ efflux)

autorhythmic cells

modified cardiac muscle cells that spontaneously generate their own electrical impulses (action potentials) without requiring nerve stimulation, unstable pacemaker potential leads to firing

what is the path of electrical conduction

SA Node → AV Node → AV Bundle → Bundle Branches → Purkinje Fibers
→ Contractile Myocardium

SA node is also the primary

pacemaker

if the SA node fails, then the ______ node can take over

AV

on an ECG a p wave represents

atrial depolarization

on an ECG the QRS complex represents

ventricular depolarization

in an ECG what does a T wave represent

Ventricular repolarization

systole is the _______ phase

contraction

diastole is the __________ phase

relaxation

first heart sound are the

AV valves closinthe

second heart sound are the

semilunar valves closing

End-Diastolic Volume (EDV)

Blood in ventricles before contraction

End-Systolic Volume (ESV)

Blood remaining after contraction

Stroke Volume (SV) =

EDV - ESV

Ejection Fraction =

Stroke Volume / EDV (% of blood ejected per beat)

Cardiac Output (CO) =

Heart Rate × Stroke Volume (~5 L/min at rest)

how does the parasympathetic system control heart rate

(ACh) it slows heart rate

how does the sympathetic control heart rate

(epi/norepi) increases heart rate and contractility

what’s the frank-starling law

Greater EDV → Stronger contraction → Higher stroke volume

name two positive inotropes

catecholamines and digitalis

what do positive inotropes do

increase contractility

name a negative inotrope

beta-blockers

what do negative inotropes do

decrease contractility

afterload is the

the pressure or resistance the heart ventricles must overcome to eject blood into the aorta and pulmonary arteries during systole

Afterload is determined by

EDV and arterial pressure

high afterload increases

cardiac workload

what are the three basic themes in physiology the cardiovascular system demonstrates

blood flows, circulation of blood, and myocardial contraction

the heart pumps blood through a closed system of _______

blood vessels

primary function of the cardiovascular system

transport of nutrients, water, gases, wastes, and chemical signals to and from all body parts

what in the heart and veins ensure unidirectional blood flow

valves

the pulmonary circulation goes from the _____ side of the heart to the _____ and back to the heart

right, lungs

the systemic circulation goes from the _________ side of the heart to the ______ and back to the heart

left, tissues

pulmonary circulation moves _________ blood from the heart to the _______ and then back to the heart

deoxygenated, lungs

systemic circulation is the pathway through which _________ blood is transported from the heart to all the body _______ and _________ blood is returned to the heart

oxygenated, tissues, deoxygenated

describe the path deoxygenated blood takes in the pulmonary circulation

• Deoxygenated blood enters the heart from the vena cava.

• The blood flows into the right ventricle, then through the

pulmonary valve, and into the pulmonary artery.

• The blood travels to the lungs, where it releases carbon dioxide

and receives oxygen.

• The blood returns to the heart through the pulmonary vein and

into the left atrium.

• The blood then flows into the left ventricle, which pumps it out

through the aortic valve and into the aorta.

describe the path oxygenated blood takes in the systemic circulation takes

• Oxygenated blood is pumped from the left ventricle of the heart
into the aorta.
• The aorta branches into smaller arteries that carry blood to the
body's tissues.
• In the capillaries, blood exchanges oxygen for carbon dioxide.
• Deoxygenated blood returns to the heart through veins.
• The veins empty into the right atrium of the heart.

hypoxia

tissues are deprived of oxygen

blood flows because liquids move from ______ to ________ pressure regions

high, low

what are the 2 components of fluid in motion

dynamic (kinetic) and lateral (hydrostatic)

the pressure of a fluid in motion decreases with ______

distance

hydrostatic pressure

The pressure exerted by a stationary column of fluid in a tube. Hydrostatic pressure is the pressure exerted by a fluid at rest. It is the force that the fluid applies on the walls of its container, or any object submerged in it.

pressure is lost (due to ______) as blood moves through

friction, vessels

_________ of the heart creates pressure without changing the volume of blood

contraction

driving pressure

pressure of the blood leaving the heart to the vessels