Transcript Notes - Belle Vernon Area School District

Cardiovascular System
I. Functions of the heart.
1. Generating _______________.
2. Routing ________________.
3. Ensuring blood moves __________.
4. _______________ blood supply.
Cardiovascular System
II. Heart
A. General Characteristics
 1.
____________time/day
 2. ____/day = ____
gallons
 3. ________ miles of
blood vessels
 4. Center of the
circulatory System
 5. Center of the Thoracic
Cavity, between the
lungs
 6. ____ on the left side
 7. ______ in size after
the age of 65.
B. Coverings of the heart
1. ___________ - covers the heart, 2 main layers
a. ___________________(pericardial sac)
•Outer
•Loose fitting
1. _________ - Outer, thick, tough
dense connective tissue.
Protects & anchors to the
diaphragm
2. _________ - Inner, thin,
Squamous epithelium
b. _____________________(Epicardium)
•Attaches to the surface of the
heart
•Considered to be the outer most
layer of the heart.
c. ________________
•Space filled with ________
•_______________
•____________ - swelling of space
Review

What is the main function of the heart?

What is the general size & shape of the
heart?

Which cavities contain the heart?
C. Heart Walls
______ layers - middle is the most
important ______________________
1. _________ - Thin protective
barrier of the heart
Serous membrane
Fat deposits
2. ___________ -Bulk of the heart
_______________- bundles of
connective tissue
Layer that contracts
3. ___________- Inner most layer
Smooth white layer
 __________________
D. Heart Chambers
Superior
1. ______________ Receiving chambers for
blood
__________role in pumping
_________- ridges of muscle
_________- separates the
atrium into right & left
halves
_________- oval depression
of the heart believed to be
an opening in the fetal heart
a. ____________- receives
from the vena cava
b. _____________receives
from the lungs
Inferior
2. _______________ - forces blood
through the body
____________- Irregular folds
of muscle in the endocardium
__________________Slender projections off of the
trabuclae carnae
 Attaches to valves & aids in
function
__________________Separates ventricles into left &
right halves
__________________- Externally
separates the atrium & ventricles
Review

What are the 3 layers of the heart from
outer to inner most?

Why is the inside of the heart coated with
simple squamous?

What are the chambers of the heart?

What wall divides the right and left sides
of the heart?
E. Heart valves
Blood flows in __________________
Prevents ___________________

1. _________________(AV) - between
atrium & ventricles
_______triangular flaps or cusps
Point downward into the
ventricles
___________ between right
Atrium & ventricle (3 flaps)
Bicuspid (mitral) between left atrium &
ventricle (2 flaps)
Chordae tendinae - strands of
connective tissue
Anchors cusps to papillary walls of the
ventricles
Murmur - Cusps do not lose completely
- leaking of blood
2. Semilunar (SL) Valves
Between ventricles & blood leaving
Pulmonary & Aortic
3 half moon (semilunar) cusps
F. Blood flow through the heart
G. Supply of blood to the heart
Coronary Circulation
Right & Left Coronary Arteries - carries fresh oxygenated blood
(70% of oxygen, only 25% to skeletal muscles, increases to 70%
during exercise)
Great & Small cardiac vein
Coronary Sinus - large vein that collects blood leaving the heart
II. Heart Physiology - Pumps blood through out the
body
A. Cardiac Cycle - contraction of both the atria &
then ventricle.
1. Systole - Contraction
2. Diastole - Relaxation
B. Heart Sounds - LUB - DUB Closing of the heart
valves
1. Lub - Closing of the AV valves
2. Dub - Closing of the Sl valves
C. Heart Conduction - Each
cardiac cycle is stimulated
by special conducting cells
in the heart.
1. Receives a signal form
the autonomic nervous
system.
2. Sinoatrial (SA) Node
“Pacemaker” - cluster of
pace setting cells
Initiates each cardiac cycle
by generating an electric
impulse.
Spread quickly through out
the atrium.
Stimulates the second
cluster of cells.
3. Atrioventricular (AV) Node,
AV. bundle, Bundle of His relays the signal to the
ventricles.
Extends down the septum of
the heart.
4. Purkinje fibers - branches of
the AV node, passes further
into the myocardium.
5. If the SA node is unable to
produce the electrical impulse
for the heart to contract, the
AV node functions as the
pacemaker
6. Slower – Ectopic beat.
D. Electrocardiogram (ECG or EKG) measures the electrical events
during a cardiac cycle
1. Detect changes in the
electrical changes in the
heart wall
2. Electrical changes produces a
changes in the ionic flow
through out the body
SA node fires send action potential.
P Wave - depolarization of the atria action potential.
QRS Wave - depolarization of the
ventricle.
T Wave ventricular repolarization of
the ventricle
PQ interval – atria contract
& begins to relax.
QT interval – ventricle
depolarizes &
repolarizes.
E. Cardiac Output - Volume of blood pumped
1. Heart rate X Stroke Volume = Cardiac Output
75 bpm X 70 ml
= 5250 ml/min (5.25
L/min)
2. Adjustments - exercise
Heart rate
Stroke Volume
3. Starling’s Law - Further the heart is stretched,
the stronger the contraction.
Preload – pressure on the heart when the
ventricles are stretched when filling with
blood.
Afterload – pressure the heart must beat
against.
F. Regulation of Heart Activity
1. Controlled by the reflex center (cardioregulatory
center) - medulla oblongata.
2. Baroreceptors - detect the blood pressure.
3. Parasympathetic fibers from the medulla
oblongata through the Vagus nerve extends to the
heart.
Acetylcholine (Ach) slows the heart
Norepinephrine (NE) speed the heart up
Barorecptor relfex
G. Cardiac cycle
Three major events in the cycle.
1. Systole –
a. Blood is pushed towards the
atria, closely the AV valves.
b. Pressure increases in the
ventricle forcing the SL valves to
open.
2. Diastole –
a. Pressure in the ventricles
decrease, the AV valves open and
blood fills the ventricles up to 70%
of their volume.
3. EndAtria relaxes & fills with blood, then
contract & starts it over.
Cardiac Cycle
III. Aging
A. By 70 output is reduced by 30%, by 85 30%60%.
B. Hypertrophy is common (enlargement of left
ventricle), due to increase afterload (high blood
pressure).
Leads to decreased elasticity & increased
stiffness.
Increased left atria pressure and cause
pulmonary edema, feel out of breath.
C. Greater amount of time to contract & relax
leading to decreased in maxmium heart rate.
D. Connective tissue with the valves becomes less
flexible.
E. Development of coronary artery disease in 10%
of people over 80.
VI. Cardiovascular diseases
A. Congestive heart failure - failure of the heart to pump
blood to the body tissues.
B. Heart Block – Failure of the SA or AV. to generate
impulses.
C. Heart fibrillation - Heart beats at a irregular pace.
D. Heart flutter - heart race up to 300 bpm.
E. Hypertension - elevated blood pressure.
F. Murmur - Leaking of blood through a closed valve.
G. Myocarditis - infection of the heart muscle.
H. Pericarditis - Infection of the pericardial sac
which results in thicken or scarring.
Cardiovascular diseases
Blood Vessel and Circulation
Functions
1. Carry Blood
2. Exchange of nutrients
3. Transport
4. Regulate blood pressure
5. Direct blood flow
I Blood Vessels - Forms a closed
circulatory system (Arteries >Capillaries ->Veins)
Made up of three layers
a. Lumen - space for the flow of blood.
b. Tunica Intima - inner lining.
c. Tunica Media - smooth muscle, contractibility.
d. Tunica Adventitia – anchoring
Review

1. State the functions of blood vessels.

2. What is the inner space called of blood
vessels?

3. What are the three layers of blood
vessels?
A. Arteries - Carries blood away
from the heart
Strong & Elastic
1. Elastic Arteries – Largest in
diameter.
Mainly elastic
2. Muscular arteries – medium
sized and small diameter.
Mainly smooth muscle
3. Distributing arteries –
vasoconstriction Vasomotor fibers of
the (autonomic).
vasodilatation - nerve
impulse is inhibited muscle relaxes &
elastic fibers recoils.
4. Small arteries
5. Arterioles - 0.5 mm in
diameter
Review

1. What are the function of arteries?

2. Why are arteries thick?

3. How are arteries adapted to handle
high blood pressure?
B. Capillaries - Thin wall
blood vessels that permit
exchanges of material.
1. Connect arteries to
veins
2. 0.01 mm in diameter lumen
3. Can only fit 1 RBC at a
time.
4. Form capillary beds or
networks.
 Thoroughfare channels connect arterioles directly
to veins
 True Capillaries - 10-100
per bed
Precapillary Sphincter - valve
that regulates flow of blood
into those capillaries.
Review

1. What is the function of capillaries?

2. How are capillaries adapted for their
function?

3. Describe a Thoroughfare channels.
C. Veins - Carries blood toward the heart
1. Thinner & collapse.
2. Holds 65% of the body’s blood.
3. Low blood pressure, too low to
be pumped back to the heart.
1 way valves
Body movement Skeletal contraction,
breathing.
4. Made up of three layers - same
as arteries
5. Varicose veins overstretched veins from
blood pooling , hemorrhoids.
6. Venules – thinner versions
of veins
Review

What is the function of veins?

How are veins adapted to handle low
pressure?

Name some ways that blood can be
“PUSHED” through the veins.
II. Blood Pressure - force exerted by
blood against the inner walls of
vessels
A. Influenced by:
Cardiac Output
Blood Volume
Peripheral Resistance which is
regulated by nerve, kidneys,
hormones.
B. Moves from regions of higher
pressure
to lower pressure
Systolic - Peak pressure - 120
mmHg
Diastolic - Resting - 70 - 80 mmHg
Sphygmomanometer - measures
blood pressure.
Stethoscope – Hearing
Korotkoff - tapping sound sounds
C. Pulse - rhythmic expanding & recoiling of an
arterial wall
Average
Adult 70 - 90 bpm
Child 80 - 140 bpm
tachycardia - heart rate is above 100 bpm at
rest
bradycardia - heart rate is lower than 60 bpm
at rest
Auscultatory Method
Sphygmomanometer
Stethoscope
Korotkoff sounds
D. Blood Pressure
Review

Define blood pressure.

Describe blood pressure movement.

Define pulse.
III Capillary Exchange
10 Billion capillaries
Materials (gases, nutrients)
move across capillary walls by
diffusion, osmosis, facilitated
diffusion & active transport.
Small amount of fluid also
moves across the capillary
walls:
Hydrostatic pressure - blood
pressure within the capillaries
Osmotic pressure - movement
of fluid from cells to plasma
90% reabsorbed back into the
blood
10% returned back by the
lymphatic system
Review

What are the functions of capillaries?

What is the purpose of hydrostatic pressure?

How does hydrostatic pressure compare to
osmotic pressure?

Which part of the capillary bed has the highest
hydrostatic pressure and osmotic pressure?
IV. Regulation of blood pressure regulation of steady pressure is
important.
A. Nervous Control - Adjusts cardiac
output & peripheral resistant by
autonomic fibers to the SA node &
reflex center (vasomotor center in
the medulla oblongata & pons).
1. Peripheral resistance - control by
activity of vasomotor between
the smooth muscle & reflex
center of Medulla (Vasomotor
tone, increases = constriction).
2. Control of vasomotor center
(MAP)
Map = CO X PR
a. Baroreceptors – located in
major vessels above the
heart & detect changes in
the blood pressure.
Moment to moment control
b. Chemoreceptors - Sensitive to
changes in oxygen levels or
hydrogen ions (pH) level.
carotid bodies – carotid sinus
aorta bodies - aorta
Review

What is the job of baroreceptors &
chemoreceptors?
V. Cardiovascular diseases
A.
Aneurysm - formation of
a sac within the heart or
blood vessels due to
stretching
B. Arteriosclerosis - Loss of
elasticity in arterial walls
C. Atherosclerosis - narrow
of arteries by plaque
build up
Cardiovascular diseases
1. What are the three types of blood vessels
and how are they different?
2. What is the difference between
vasodialation & vasoconstriction?
3. What are the 3 layers of the blood vessels?
4. Does blood ever flow in reverse within the
blood vessels?