Download the heart <3

THE HEART <3
BLOOD AND THE HEART FUN FACTS
♦ An average adult human contains
about 5 liters (5.3qt) of blood.
♦ The blood makes up about onethirteenth
of the body’s weight.
♦ The adult heart weighs about 280 grams (10 oz.)
♦ At rest, the heart pumps out about 80 millimeters
(2.6 oz) of blood with each beat.
♦ The heart beats, on average, 70 times each
minute at rest.
♦ This means all the blood is circulated (goes
round the body once) in about one minute.
♦ During strenuous exercise the heart can pump
six to eight times the amount of blood that it
pumps at rest.
Superior vena cava and
inferior vena cava – bring
deoxygenated blood to
right atrium
Pulmonary artery – takes
blood away from right
ventricle to the lungs for
O2
Pulmonary veins – bring oxygenated
blood
from lungs to left atrium
Aorta – takes blood away from left
ventricle to
rest of the body
Chambers and Valves
• SEPTUM divides into R and L
halves
• Upper chambers – RIGHT
ATRIUM and LEFT ATRIUM
• Lower chambers – RIGHT
VENTRICLE and LEFT VENTRICLE
• Four heart valves permit flow
of blood in one direction
-TRICUSPID VALVE – between right
atrium and
right ventricle
-BICUSPID (MITRAL) VALVE – between
left atrium
and left ventricle
-Semilunar valves are located where
blood leaves
the heart - PULMONARY SEMILUNAR
VALVE
and AORTIC SEMILUNAR VALVE
The heart=a muscular double pump with 2 functions
The right side receives
oxygen-poor blood
from the body and
tissues and then pumps
it to the lungs to pick
up oxygen and dispel
carbon dioxide
 Its left side receives
oxygenated blood
returning from the
lungs and pumps this
blood throughout the
body to supply oxygen
and nutrients to the
body tissues

8
9

Two circulations
 Systemic
circuit: blood vessels that
transport blood to and from all the body
tissues
 Pulmonary
circuit: blood vessels that carry
blood to and from the lungs
Chambers of the heart
sides are labeled in reference to the patient facing you

Two atria
 Right
 Left
atrium
atrium
--------------------------------------------------------------------------------

Two ventricles
 Right
 Left
ventricle
ventricle
10
Valves
three: tricuspid
one: bicuspid

to pulmonary trunk (branches R and L)
Bicuspid valve (the bicuspid one)
 LA

to RV
Pulmonary valve
 RV

(cusp means flap)
“Tricuspid” valve
 RA

11
to LV
Aortic valve
 LV
to aorta
Function of AV valves
12
Function of semilunar valves
(Aortic and pulmonic valves)
13
Meet the Heart

http://www.youtube.com/watch?v=Vi1JK6IYVt8
Pattern of flow
15
(simple to more detailed)

Body

RA

RV

Lungs

LA

LV

Boby
Body to right heart to lungs to
left heart to body
Body, then via vena cavas and
coronary sinus to RA, to RV, then to
lungs via pulmonary arteries, then to
LA via pulmonary veins, to LV, then
to body via aorta
From body via SVC, IVC & coronary
sinus to RA; then to RV through
tricuspid valve; to lungs through
pulmonic valve and via pulmonary
arteries; to LA via pulmonary veins; to
LV through mitral valve; to body via
aortic valve then aorta
LEARN THIS
PHYSIOLOGY OF THE HEART
The heart is a double pump. When the
heart
beats…
Right Heart
Deoxygenated blood flows into heart
from vena
Cava ---right atrium ---tricuspid valve--right
ventricle --pulmonary semilunar valve--pulmonary artery ---lungs (for oxygen)
Left Heart
Oxygenated blood flows from lungs via
pulmonary
Veins--- left atrium--- mitral valve--- left
ventricle--aortic semilunar valve--- aorta --- general
circulation (to deliver oxygen)
Control of Heart Contractions
SA (sinoatrial) NODE = PACEMAKER
• Located in right atrium
• SA node sends out electrical impulse
• Impulse spreads over atria, making them
contract
• Travels to AV Node
AV (atrioventricular) NODE
• Conducting cell group between atria and
ventricle
• Carries impulse to bundle of His
BUNDLE OF HIS
• Conducting fibers in septum
• Divides into R and L branches to network of
branches in ventricles (Purkinje fibers)
PURKINJE FIBERS
• Impulse shoots along Purkinje fibers causing
ventricles to contract
Flow Through the Heart

http://www.youtube.com/watch?v=7XaftdE_h60
Heart Contraction
SA Node
Sinalarterial
node
“Pacemaker”
AV Node
Atrioventricular
node
Allows impulse to
cross
into ventricles
Bundle of His
Bundle
Branches
Purkinje
Fibers
Heart Contraction Flow Chart
SA Node fires
↓
Impulse spreads across atria
↓
Atria depolarizes
↓
Atria contract (lub)
↓
Blood is pumped to the ventricles
↓
AV Node receives impulse from SA Node
↓
Impulse passes through bundle of His
↓
Impulse passes through Purkinje fibers
↓
Ventricles depolarize and contract (dub)
↓
Blood is pumped into the lungs and out to the body
Electrical conduction system: 21
specialized cardiac muscle cells that carry impulses
throughout the heart musculature, signaling the
chambers to contract in the proper sequence
(Explanation in next slides)
Conduction
system

SA node (sinoatrial)
 In wall of RA
 Sets basic rate: 70-80
 Is



the normal pacemaker
Impulse from SA to atria
Impulse also to AV node via internodal pathway
AV node
 In interatrial septum
22
Conduction continued

SA node through AV bundle (bundle of His)
 Into interventricular septum
 Divides
R and L bundle branches
become subendocardial
branches (“Purkinje

fibers”)
Contraction begins
at apex
23
24
EKG→ measures heart electricity
P Wave→ Atria contract & Depolarize
PQ Interval→ Impulse is passing through the bundle of His to the Purkinje
fibers
QRS Wave→ Ventricles depolarize and contract
T Wave→ Ventricles repolarize
Cardiac Cycle
Blood enters the atria through the vena cava (R) and the
Pulmonary vein (L)
↓
Atria will contract
↓
Blood is pushed through the AV valves into the ventricles
↓
Ventricles contract and AV valves close
↓
Blood is pushed though the pulmonary and aortic semilunar
valves into the pulmonary trunk and the aorta
↓
Ventricles relax and valves close
Cardiac Cycle Tutorial

http://faculty.alverno.edu/bowneps/cardiaccycle/cardiaccycle1m
ap.htm