Download File - WKC Anatomy and Physiology

Human Anatomy and
Physiology
Unit IV
Circulation and Body
Defense
Part II
The Heart
Resources
Your textbook – Chapter 20
Your lab manual – Exercise 27 and 28
Wiley PLUS
Heart Topics
1.
2.
3.
4.
5.
6.
7.
8.
Location of the Heart
Chambers of the Heart
Heart Valves
Coronary Circulation
Cardiac Muscle
Cardiac Conduction System
Cardiac Cycle
Cardiac Output
Location of the Heart
The heart is located in the mediastinum,
where it is surrounded by a doublelayered pericardium
Location of the Heart
The heart is located
in the mediastinum,
where it rests on
the diaphragm
Location of the Heart
Two-thirds of the
heart lies to the
left of the midline
Location of the Heart
Location of the Heart
The heart is
enclosed and held
in place by the
pericardium
Location of the Heart
1. Outer fibrous pericardium
2. Inner serous pericardium
A) Parietal layer
B) Visceral layer
Pericardium
Pericardium
Parietal pericardium
Visceral Pericardium
Pericardial Diseases
Pericarditis
Inflammation of the
pericardium
Pericardial effusion
Passage of fluid into the
pericardial cavity
Often due to congestive
heart failure
Pericardial Diseases
Cardiac tamponade
Bleeding into the
pericardial cavity
Pericardial Diseases
Heart Topics
1.
2.
3.
4.
5.
6.
7.
8.
Location of the Heart
Chambers of the Heart
Heart Valves
Coronary Circulation
Cardiac Muscle
Cardiac Conduction System
Cardiac Cycle
Cardiac Output
Location of the Heart
The wall of the four-chambered heart has
three layers: (1) epicardium, (2)
myocardium, and (3) endocardium
Layers of the Heart Wall
Epicardium
Myocardium
Endocardium
Chambers of the Heart
Right atrium
Right ventricle
Left atrium
Left ventricle
Chambers of the Heart
Anterior View
Posterior view
Chambers of the Heart
Right atrium and
right ventricle
pump blood to the
lungs
Chambers of the Heart
Left atrium and left
ventricle pump
blood to the rest of
the body
Coronary Sulci
Coronary sulcus
Anterior
interventricular sulcus
Posterior
interventricular sulcus
Coronary Sulci
Coronary sulcus
Anterior
interventricular sulcus
Posterior
interventricular sulcus
Right Atrium
Forms the right
border of the heart
Receives blood
from:
Superior vena cava
Inferior vena cava
Coronary sinus
Right Atrium
Forms the right
border of the heart
Receives blood
from:
Superior vena cava
Inferior vena cava
Coronary sinus
Right Atrium
In between the
atria is the
interatrial septum
Fossa ovale
Right Atrium
Posterior atrial wall
is smooth
Anterior wall is
rough.
Pectinate muscle
Right auricle
Right Atrium
Right Atrium
Blood leaves the
right atrium
through the
tricuspid valve
Right Ventricle
Forms most of the
anterior surface of
the heart
Right Ventricle
Right and left
ventricles are
separated from
each other by the
interventricular
septum
Right Ventricle
The inside of the
right ventricle
contains muscular
ridges called
trabeculae carnae
Right Ventricle
Blood leaves the
right ventricle
through the
pulmonary
semilunar valve
Pulmonary trunk
Right and left
pulmonary arteries
Left Atrium
Forms most of the
base of the heart
Receives blood
from the pulmonary
veins
Left Atrium
The left atrium is
separated from the
right atrium by the
interatrial septum
Left Atrium
The walls of the left
atrium are smooth
except for the
auricle
Left Atrium
Blood leaves the
left atrium through
the bicuspid valve
Left Ventricle
Forms the apex of
the heart
Left Ventricle
Receives blood
from the left atrium
Bicuspid valve
Chordae tendinae
Papillary muscles
Left Ventricle
Blood leaves the
left ventricle
through the aortic
semilunar valve
Ligamentum
arteriosum
Atrial Septal Defects
Incomplete closure of the
foramen ovale.
Ventricular Septal Defects
Incomplete formation of
the interventricular
septum.
Myocardial Thickness and Function
Atrial walls are
thinner than
ventricular walls
Walls of the right
ventricle thinner
than walls of the
left ventricle
Fibrous Skeleton
Four dense
connective tissue
rings wrapped
around the four AV
valves of the heart
Heart Topics
1.
2.
3.
4.
5.
6.
7.
8.
Location of the Heart
Chambers of the Heart
Heart Valves
Coronary Circulation
Cardiac Muscle
Cardiac Conduction System
Cardiac Cycle
Cardiac Output
Location of the Heart
Heart valves ensure that blood flow is one
way
Heart Valves
Left AV valve (bicuspid)
Right AV valve (tricuspid)
Pulmonary semilunar
valve
Aortic semilunar valve
AV Valves
An AV valve opens
towards the ventricle
One-way due to
pressure gradient
Backflow prevented
by papillary m. and
chordae tendinae
SL valves
An SL valve opens
towards the artery
One-way due to
pressure gradient
Backflow prevented
by shape of valve
Heart Murmers
Valve incompetence
Valve stenosis
Valve Implants
Heart Topics
1.
2.
3.
4.
5.
6.
7.
8.
Location of the Heart
Chambers of the Heart
Heart Valves
Coronary Circulation
Cardiac Muscle
Cardiac Conduction System
Cardiac Cycle
Cardiac Output
Blood Flow
Systemic circulation
Pulmonary circulation
Coronary Circulation
Lt. coronary a.
Left anterior descending a.
Circumflex a.
Rt. coronary a.
Posterior descending
coronary a.
Cardiac Veins
Great
Middle
Small
Anterior
Athersclerosis
Coronary Bypass
Heart Topics
1.
2.
3.
4.
5.
6.
7.
8.
Location of the Heart
Chambers of the Heart
Heart Valves
Coronary Circulation
Cardiac Muscle
Cardiac Conduction System
Cardiac Cycle
Cardiac Output
Cardiac Muscle
© Jason Taylor
Cardiac Muscle
© Jason Taylor
Heart Topics
1.
2.
3.
4.
5.
6.
7.
8.
Location of the Heart
Chambers of the Heart
Heart Valves
Coronary Circulation
Cardiac Muscle
Cardiac Conduction System
Cardiac Cycle
Cardiac Output
Cardiac Conduction System
Action Potentials in Cardiac Cells
Rapid Depolarization
Plateau
Repolarization
Refractory Period
The ECG
P Wave
QRS Complex
T Wave
ECG
Heart Topics
1.
2.
3.
4.
5.
6.
7.
8.
Location of the Heart
Chambers of the Heart
Heart Valves
Coronary Circulation
Cardiac Muscle
Cardiac Conduction System
Cardiac Cycle
Cardiac Output
The Cardiac Cycle
Atrial Systole
Ventricular Systole
Relaxation Period
Atrial Systole
ECG Connection: from P
wave to Q wave
AV valves: open
SL valves: closed
Atrial Systole
Both atria contract
Atrial pressure increases
AV valves open
Blood flows into both
ventricles
Ventricles are relaxed
Ventricular pressure too
low to open SL valves
Ventricular Systole
Divided into two periods
isovolumetric ventricular
contraction
ventricular ejection
Atria are relaxed and
filling with blood
Isoventricular Ventricular Contraction
ECG Connection: begins
with R wave
AV valves: closed
SL valves: closed
Isoventricular Ventricular Contraction
Both ventricles begin
contracting
Ventricular pressure
increases
AV valves close
Ventricular pressure too
low to open SL valves
SL valves remain closed
Ventricular Ejection
ECG Connection: from
S wave to T wave
AV valves: closed
SL valves: open
Ventricular Ejection
Both ventricles
continue contracting
Ventricular pressure
continues to increase
AV valves remain closed
High ventricular
pressure opens SL
valves
Blood is ejected into
pulmonary trunk and
aorta
Stroke Volume
Stroke volume - the
volume of blood ejected
from each ventricle
during systole.
SV= EDV-ESV
SV =130 ml – 60 ml
SV = 70 ml
Relaxation Period
Divided into two
periods:
Isovolumetric ventricular
relaxation
Passive ventricular filling
Both atria and ventricles
are relaxed and filling
with blood
Isovolumetric Ventricular
Relaxation
ECG Connection: begins
at end of T wave
AV valves: closed
SL valves: closed
Isovolumetric Ventricular
Relaxation
Both ventricles begin to
relax
Ventricular pressure
begins to decrease
Low ventricular pressure
closes SL valves
Ventricular pressure too
highto open AV valves
Passive Ventricular Filling
ECG Connection: after T
wave to next P wave
AV valves: open
SL valves: closed
Passive Ventricular Filling
Both ventricles continue
to relax
ventricular pressure
continues to decrease
SL valves remain closed
Atrial pressure exceeds
ventricular pressure
AV valves open
Blood fills the ventricles
Cardiac Cycle and Heart Rate
Durations of atrial and ventricular systole
are relatively constant
Increased heart rate  decreased
relaxation period
Heart Topics
1.
2.
3.
4.
5.
6.
7.
8.
Location of the Heart
Chambers of the Heart
Heart Valves
Coronary Circulation
Cardiac Muscle
Cardiac Conduction System
Cardiac Cycle
Cardiac Output
Cardiac Output
Cardiac Output (CO) = SV X HR
At rest CO = 70 X 75
At rest CO = 5.25 L/minute
Cardiac Reserve = 5 X CO
CO adjusted by changing SV or HR
Regulation of Stroke Volume
Preload
Contractility
Afterload
Preload
Increased stretch  increased
force of contraction
Increased filling during
diastole  increased force of
contraction during systole
Determined by:
Duration of ventricular diastole
Venous return
Why Preload?
The relationship between ventricular
filling (EDV) and preload equalizes the
output of the right and left ventricles and
keeps the same volume of blood flowing
to both systemic and pulmonary
circulations.
Contractility
Positive inotropics
increase contraction
Norepinephrine and
epinephrine
Negative inotropics
decrease contraction
Acetylcholine
Afterload
Afterload – the pressure that
the ventricles must overcome to
open the SL valves.
Increased afterload 
decreased SV
Regulation of Heart Rate
Regulating HR is the body’s principal
mechanism of short-term control of CO
Three main mechanisms:
1. ANS
2. Endocrine system
3. Other factors
Regulation of Heart Rate - ANS
Regulation of Heart Rate - Endocrine
Epinephrine and Norepinephrine
Increase HR and contractility
Thyroid hormone
Increases HR and contractility
Cations also affect heart rate:
Na+ and K+ decrease HR and contractility
Ca2+ increases HR and contractility
Regulation of Heart Rate – other factors
Cations also affect heart rate:
Na+ and K+ decrease HR and contractility
Ca2+ increases HR and contractility
EXERCISE AND THE HEART
Exercise and the Heart