Download Heart Anatomy

Cardiovascular System
Functions:
Generate__________
__________
Routes _________
Regulates ________ and
_________ of blood
flow
A muscular pump and network of vessels
to distribute blood to ENTIRE body
15.2 Heart Anatomy
Base: to apex: ~ 14cm
Describe the location of
heart.
What is the name of this
Anatomical region?
Membranes
double-walled sac =
1) outer layer, tough, dense
connective = _________
-protects, anchors and prevents
overfilling
2) inner, 2-layered = _________
_________and _________
___________ aka
epicardium
Between the 2 layers of serous
is cavity with serous fluid =
pericardial fluid
Wall of Heart
3 layers:
1) Outer epithelial &
connective = ________
2) Middle cardiac muscle
= ____________
3) Innermost epithelial &
connective is
continuous with vessels
= _____________
Chambers & Landmarks
Superior = _______ = RECEIVERS
of blood, has auricles WHAT are the
vessels that deliver?
Divisions =
________ and
_______;
sulces on
surface only
Inferior = ________ right one is most
of ant. surface, left one is
inferoposterior surface and is the
______.
Ventricles form and function
Bulk of heart: they are
________ due to pressure
generated when muscles
_________.
Interior: irregular bundles
of muscle = trabeculae carneae
Chordae tendinae:
papillary muscle:
When contraction: right ventricle sends blood to =
and left ventricle sends blood to =
Atrioventricular (A-V) valves prevent
backflow into atria when ventricles
contract
Right valve =
left =
Heart relaxes = VALVES
________. Blood enters atria
and passively flows into
ventricles.
Heart contracts = VALVES
________.
Semilunar valves: Named for vessels
(pulmonary & aorta) and appearance
As ventricles contract,
pressure is ________ in
the ventricles than the
vessels they
serve…VALVES
______.
Blood rushes into vessels,
as soon as pressure is
_________ in
vessels…VALVES
__________.
Fibrous skeleton of heart
• Elastin and collagen,
thicker around heart
valves and where great
vessels leave heart
• Reinforces the
myocardium, ________ &
________valves
•
Also INSULATES to
prevent electrical
stimulation.
How does blood move through heart?
2 pumps that have separate circuits
PULMONARY=Right side
SYSTEMIC =Left side
• Blood returns to right
atrium, O2 poor and CO2
rich (what vessels?)
• Blood flows from atrium to
ventricle (valve?)
• From right ventricle leaves
via pulmonary artery (valve?)
• gas exchange occurs in
______
•
blood from lungs to left
atrium (what vessels?)
• passes into left ventricle
(valve?)
• leaves through aorta
(valve?)
• ALL tissues of body
Compare and contrast
Equal volumes moved by each side BUT
____________ = less mileage and lower
pressure system (24 and 8 mmHg)
____________ = 5 times more resistance
(friction) much longer and high pressure
(120 and 80 mmHg)
How does this affect appearance?
Coronary circuit
Heart is large muscle VERY metabolically active,
needs own supply of oxygen and nutrients
Lots of individual variation and collateral
circulation…WHY?
15.3 Heart Action
Initiation & perpetuation of cardiac cycle =
blood flow through heart from contraction to
contraction driven by __________.
_______ are primer pumps = fill ventricles with blood
__________ are power pumps = move blood to body
Blood moves out of chambers during _________ also
known as _________ and into chambers during
___________ also known as ___________.
Ventricular filling: diastole
Blood returning to heart
AV valves are______,
SL valves are _________
• Pressure in ventricle is
_________than atria
• 70% of ventricular filling
will occur passively
• Atrial systole: delivers
30% of blood.
Ventricular systole
Atria relax = atrial ________
Ventricles begin contraction,
pressure rises as soon as it is
_______ atria AV valves will
___________.
As soon as pressure in ventricles
> vessels, SL valves _______ and
ventricular ejection occurs
Understand cause and
effect…..
Your health is dependent on ________ ________.
Blood flow is controlled by ________and ______of
valves.
Valves are controlled by _________.
Pressure changes are result of __________ and
________ of myocytes/muscle.
Let’s add the sound effects to
this…..Heart sounds
• Lubb-dupp = closing of
valves and slowing of
blood flow.
• Lubb = ________valves,
beginning of ________ as
ventricular pressure rises
• Dupp = _________valves,
beginning of ventricular
_________.
Heart murmurs
-valve problem
If incompetent valve, hear
swishing as the blood
regurgitates through valve,
after closes
If stenotic valve, high pitched
sound or click due to
restricted flow through the
valve, before closes
Workload increases and over time
weakens heart
So what “drives” these pressure
changes? Cardiac conduction system:
Noncontractile cells to
initiate and distribute
the impulses/action
potential (assisted by
the gap junctions)
NAME the 6 components.
How do you get started?
Right atria, inferior to S.V.C.
Spontaneous due to decrease in K+
and increase in Ca++ and Na+
permeability
Inferior portion of interatrial septum
above tricuspid valve
Generates impulses ~
75/minute (rate in the
absence of neural and
hormonal factors is 100)
ONLY electrical
connection between atria
and ventricles (insulated by
fibrous skeleton)
Sets the pace since it is
fastest
Impulse is delayed here to let
atria respond and contract due to
smaller fibers and fewer gap
junctions.
Moving into the septum & through
the ventricles
aka bundle of His
Superior part of interventricular
septum
Divide into the right and
left branch….These serve
the respective ventricles
Responsible for the bulk of
ventricular depolarization
Course along septum
toward the apex
Rapid conduction, which
allows ventricular muscle
to contract simultaneously
How do we measure this?
Electrocardiogram (ECG or EKG)
• Composite of all APs generated by nodal and
contractile cells through time
• Measures electrical activity from surface of body
(12 leads system)
3 discernable waves, Name
them.
Depolarization Waves
• P wave = ________
_______ from SA node
through atria, 0.1 sec after
P wave begins, atria
_________.
• QRS = __________
________ shape reflects
the change in
paths….leads to
contraction
The heart must “reset”
____________ = ventricular
repolarization, this marks
the ___________AND the
inability to respond to
another AP (refractory
period)
Atrial repolarization occurs during
ventricular depolarization
As blood rebounds
off the closed valves
get spike in pressure
= dicrotic notch
Needs change….how do you
regulate?
Heart rate: affected
by___________(vagus
nerve)
&____________(accelerato
r nerve)
_________stimulation
dominates at rest
When either system is
stimulated the other is
_________.
Medulla to SA and AV nodes.
Baroreceptor reflex
Changes in blood pressure affect
the amount of stretch in the vessel
walls of aorta and carotids
Sensory =
Integrator/Coordinator =
Response =
(activate P.S.)
=
(activating sympathetic)
Other influences on regulation
Name 4 other things that can influence Heart Rate.
15.4 Blood Vessels
So now you know what blood does (and
what is in it)
You know what moves it
BUT…how does it get to the cells?
Leaving the heart = _______,
they branch/diverge as get
smaller become __________.
Arterioles become __________
smallest diameter = exchange
Going back to _______ = capillaries
become _________join/converge as
get larger = _______.
Structure: 3 tunics
Innermost called _______ or
________ : endothelium
=simple squamous
The middle is _______: smooth
muscle = bulk, controlled by
ANS =vasomotor control
The outermost is _________or
__________: connective
tissue = collagen, anchors
amount & type of tissue determines
and protects
vessel and its function
Arteries: leave heart & deliver
blood
• Elastic: Most elastin (in ALL 3 layers) more elastin
than muscle,allows expansion and contraction/recoil
with pressure and volume fluxes
• muscular/distributing :media-mostly smooth
muscle, more active in vasoconstriction &
vasodilation= ability to control blood pressure and
flow
Arterioles become
metarteriole
__________ directly
controls what capillary
beds get perfused, large
ones have 3 layers….
But as get close to
capillaries have ONLY
__________& bands of
_______ _________.
What controls SM contraction?
Control of blood flow through
capillary beds
1) ___________ ___________
aka. metarteriole-thoroughfare
channel, short vessel that
directly connects the arteriole
and venule = BYPASS
2) __________ _________
(smooth muscle fiber) acts as
valve to regulate flow into
bed
Bed can be flooded or completely bypassed depending on need
of tissue or organ
Capillaries = EXCHANGE
• Only _______ ________
…designed for exchange!
Permeability varies from tissue
to tissue: in muscle = ______;
in kidney, endocrine,
intestines = ________; in
bone marrow, liver, spleen =
___________
NONE in cartilage, epithelia, lens and
cornea
LOTS in skeletal, cardiac lungs, kidneys
Correlates with metabolic activity
Hydrostatic Pressure: Drives fluids _____
of blood via filtration
Colloidal Osmotic pressure (OP): ______
hydrostatic pressure KEEP water(fluid) ___
capillary.
Net pressure determines
movement of fluids
Fluid leaves the capillary if the HP is ______
_______OP and enters the capillary if the OP
is ______ ______ HP
What happens to excess fluid?
Note if pressures change SO does the movement of fluid
Venules: going back to heart
• 10 – 100 mm
• Look a lot like capillaries
• Postcapillary venules = endothelium and
connective tissue
• Somewhat porous & permeable
veins
3 distinct tunics : BUT
always _______ walls
• Tunica ______ is thin
and poorly developed
• Tunica ________ is
thickest with collagen
and elastin = highly
distensible
• Larger __________
Venous blood pressure
Steady with VERY little
change (little resistance here,
BIG lumens)
Dissipates from ~20 mmHg
to nearly 0 mmHg at vena
cavae
So how do we get it to heart?
Valves & “pumps”
DESCRIBE THESE
15.5 Blood pressure (mm Hg)
Force per unit area exerted on a vessel wall by the
contained blood
Greatest force in the largest arteries near heart
(systemic arterial BP) due to __________________.
1) How much vessels
can be stretched
(compliance)
2) Volume of blood
forced into them
Pulsatile since
amount of blood
entering & leaving
fluxes constantly
What happens in systole?
What is diastole?
You can feel this = pulse
Difference between
systolic and diastolic =
expansion and recoil of
arteries
Anywhere in arterial tree
that can be compressed
against firm tissue =
pulse points
Factors that influence blood
pressure:
1)Heart action= stroke volume (SV), heart rate (HR),
2) vessel characteristics = resistance 3) blood
characteristics = viscosity & volume
So heart imparts pressure
and vessels work to
maintain this without being
damaged
the goal is maintaining
BLOOD FLOW
Heart Action = cardiac output
(C.O.)
• Amount of blood pumped out of each ventricle in
1 minute
• DEPENDS ON
________ ___________= volume of blood pumped
out by one ventricle in a “beat” generally related to
force of contraction
________ ______= contractions per minute
What is the math formula for cardiac output?
What’s this got to do with
pressure?
• Blood pressure varies _______ with cardiac
output
• SV increases or HR increases = ________ in
blood pressure
• SV decreases or HR decreases = ________ in
pressure
Blood Volume
• Usually ~ 5 to 6 L (8% of mass) varies with
age, size and sex
• Pressure is __________ related to the
volume (think about water faucet, turn up
flow what happens)
• Loss of blood = ________ pressure
Resistance (peripheral) = P.R.
• This is the friction between the blood and the vessel
wall.
• If friction increases what happens to flow? So what
must blood pressure do to re-establish flow?
MOST important factor:
___________ of the vessel
vasoconstriction or
vasodilation will alter BP!!!
Viscosity
• Ease of the movement of molecules in a solution
In blood this is due to amount of what?
• So increase in viscosity will __________
friction/resistance and what would the pressure
need to do to re-establish flow?
• Do you remember what we call an increase in
rbcs? How about a decrease?
So let’s look at this
relationship….
• Blood pressure (B.P.) is the result of 1) C.O.
which is S.V. & H.R. AND 2) P.R.
• B.P. = C.O. (amount of blood leaving heart over
period of time) “X” the P.R. (the forces that slow
or speed up movement = size of vessel and
viscosity of blood)
S.V. and H.R, ultimately are affected
by….NEURAL, CHEMICAL &
MECHANICAL
What is the mathematical formula to
determine stroke volume? ( blood collected
- blood left behind after contraction)
____ ______ ______depends on how long
diastole lasts and venous pressure = PRELOAD
____ ________ _________depends on arterial blood
pressure = AFTERLOAD and force of ventricular
contraction =CONTRACTILITY
Preload: degree of stretch on
heart
• How much are myocytes stretched BEFORE contraction
(mechanical) is due to ________ ________.
While resting SkM are kept near
optimal length for developing
tension, cardiomyocytes are
shorter
Can also increase venous return with increase sympathetic
stimulation (recall venous reserves, fig 15.32)
Venous Pressure
• If LOW, sympathetic can stimulate VSM to
contract/constrict which increases venous return,
• Systemic venous blood returns to which chamber?
=central venous pressure
If heart beats weakly then blood remains in heart and
the pressure increases, which decreases venous
return affecting heart’s function and can lead to
peripheral edema
Venous return
more blood returns = more stretch = _____
_________ = more contraction = more ______
__________ = more cardiac output
This is the Frank Starling law of the heart
• Slow heart rate, or exercise increase cardiac
output making heart more efficient
Contractility
• Increase in contractile strength (at a given preload)
due to Ca++ influx into cytoplasm of myocytes
• Affected by neural (ANS) and chemical
(epi/norepi & T.H.)
• As increases, eject ______ blood from heart =
__________ ESV and increase SV.
Afterload: back pressure
• Pressure in vessels that must be overcome for
ventricles to eject blood, through S.L. valve
(80mmHg in aorta, 8 mmHg in pulmonary)
• DO you see WHY Hypertension reduces blood
leaving heart? It __________ESV and decreases
SV
Heart MUST work harder to move blood
Vasomotor Center = P.R.
• This in conjunction with cardiac center =
cardiovascular center in medulla
• Functions to alter cardiac output AND _______
___________
• Uses __________ (efferent) nerves, transmits
nearly constantly = constant moderate constriction
or vasomotor tone in vessels
Vasomotor tone
• Varies from organ to organ…skin and digestive
are normally more constricted
• Any increase in sympathetic activity will _______
vasoconstriction (skin & viscera = increasing
MAP)
= important regulator of blood pressure (organ)
So moment to moment regulation
Cardioinhibitor reflex
In opposite circumstances =
cardioaccelerator
And the vasomotor center
contributes
Local control of blood flow
How tissues and organs control flow
to meet their needs,
Metabolic, neural, hormonal, longterm
Tissue Perfusion
1) Delivery of O2 and nutrients and Removal
of waste
2) Gas exchange in lungs
3) Absorption of nutrients from digestive tract
4) Urine formation
Rate of blood flow needs to be precisely what
the tissue/organs need to fulfill this
Local regulation of Flow
Autoregulation: automatic adjustment to the local
needs of tissue done via metabolite monitoring
• Inadequate perfusion = decrease _____ and
___________= decrease metabolic activity which
can lead to __________.
• What can happen if too much perfusion?
Mechanisms
• By varying the resistance of arterioles,
control blood into capillary beds via
___________ _______________ (also
angiogenesis for long-term)
• While the mean arterial pressure (MAP) is
relatively constant (homeostasis), blood
flow in organ is controlled intrinsically
Metabolic controls
• Decline in ____________
• Presence of __________, ___________
____________, e.g, histamines and kinins,
and ____________,e.g, K+, H+, adenosine,
lactic acid, CO2
Causes vasodilation and relaxation of
precap. sphincters
Neural controls of vessels
• MOSTLY affect the peripheral resistance
due to ____________ division (innervate
most blood vessels EXCEPT capillaries and
precap sphincters which have no nerves)
• Goals? Why do you need to do this?