Transcript Cardiovascular System

Cardiovascular
System
THE HEART AND
CIRCULATORY SYSTEM
Heart Anatomy
Size: approximately the size of a person’s fist
Left side of thoracic cavity
Coverings: Pericardium
Double layered sac
Contains 10 – 20 cc. Of pericardial fluid to reduce
the friction of the beating heart
Heart Wall
Myocardium: heart muscle; thicker on left side of
the heart
Chambers
Atria (L & R Atrium)
2 upper chambers of heart
Thin walls, smooth inner surface
Foramen ovale: passageway between the 2 atria so
that the lungs are bypassed in the developing fetus
Cont. (Atrium)
Fossa ovale: scar tissue where the foramen ovale
existed until it closed up shortly after birth
Responsible for receiving blood
Ventricles
Thicker walls, irregular inner surface
Contain chordae tendineae (prevent heart valves from
turning inside out when ventricles contract)
Left wall 3 times as thick as right wall; forms apex of
heart
Responsible for pumping blood away from the heart
Accessory Structures
Septum: muscular wall dividing the heart into right
and left halves
Heart valves – prevents the backflow of blood
Great Vessels
Superior and inferior vena cava: receive deoxygenated blood
from all parts of the body
Pulmonary arteries: carry deoxygenated blood to the lungs
from the right ventricle
Pulmonary veins: carry oxygenated blood to the left atrium
from the lungs
Aorta: carries oxygenated blood to distribute to all parts of
the body
Pathway of Blood Through the Heart and
All Body Tissues
1. Superior and inferior vena cava
2. Right atrium
3. Tricuspid valve
4. Right ventricle
5. Pulmonary semilunar valve
Continue pathway
6. Pulmonary arteries
7. Lungs ( O2 and CO2 exchange = external respiration)
8. Pulmonary veins
9. Left atrium
10. Bicuspid/Mitral valve
Continue pathway
11. Left ventricle
12. Aortic semilunar valve
13. Aorta - all parts of body via arteries
Cont. pathway
14. Arterioles
15. Capillaries of individual tissues (O2 and CO2
exchange = internal respiration)
16. Venules
17. Veins
18. Superior and inferior vena cava
Cardiovascular Circuits
Pulmonary circuit: transport of blood from the right side
of the heart to the lungs and then back to the left side
of the heart
Systemic circuit: transport of blood from the left side of
the heart to all parts of the body and then back to the
right side of the heart
Coronary circuit: transport blood from the left side of
the heart to the heart tissues and back to the right
side of the heart
Valves
Tough fibrous tissue between the heart chambers and major blood vessels of the
heart
Gate-like structures to keep the blood flowing in one direction and to prevent
regurgitation or backflow of blood
Atrioventricular valves: when ventricles contract, blood is forced upward and the
valves close; attached by papillary muscles and chordae tendineae
Tricuspid valve: between the right atrium and the right ventricle
Bicuspid/mitral valve: between the left atrium and the left ventricle
continue Valves
Semilunar Valves: 3 half moon pockets that catch
blood and balloon out to close the opening
Pulmonary semilunar valve: between the right
ventricle and the pulmonary arteries
Aortic semilunar valve: between the left ventricle
and the aortic arch/aorta
5. Heart Sounds
When the AV (atrioventricular) and semilunar
valves close, they make the sound heard as “lubdub” (auscultated with stethoscope)
Cardiac Circulation (Blood Supply to the
Heart)
1. Aorta - coronary arteries - capillaries in myocardium
coronary veins - coronary sinus - right atrium
2. Blood in chambers nourishes endocardium
3. Coronary circuit open ONLY during relaxation phase of
cardiac cycle
4. Occlusion of coronary artery - myocardial infarction (heart
attack) if collateral circulation is inadequate
Heart
Physiology
Nerve Supply to Heart
Alters rate and force of cardiac contraction
Vagus nerve (parasympathetic nervous system):
slows heart rate
Sympathetic nerves: increase heart rate
Epinephrine/Norepinephrine: increase heart rate
Nerve supply to heart
Sensory (afferent) nerves: detect atria being
stretched and lack of oxygen (changes rate of
contractions)
Angina: chest pain due to lack of oxygen in
coronary circulation
Automaticity
Enables heart to contract rhythmically and continuously
without motor nerve impulses
SA (sinoatrial) node: pacemaker located where the superior
and inferior vena cava enter the right atrium
▪ http://www.argosymedical.com/Circulatory/samples/ani
mations/Heart%20Conduction%20System/index.html
AV (Atrioventricular) node: sends impulses to ventricles
Purkinje fibers: in heart wall to distribute nerve impulses
Overview
of Blood
Vessels
Arteries
ALWAYS Carry blood AWAY from the heart
All BUT pulmonary arteries carry oxygenated blood
Aorta: largest artery; 1 inch in diameter
Arterioles: smallest arteries
Arteries
Coronary arteries: most important; supply blood to
the heart muscle
Veins
Carry blood TOWARD the heart
All BUT pulmonary veins carry deoxygenated blood
Layers much thinner, less elastic
Series of internal valves that work against the flow of gravity to prevent reflux
Superior and inferior vena cava: largest veins
Venules: smallest veins
Capillaries
Tiny, microscopic vessels
Walls one cell layer thick
Function: to transport and diffuse essential
materials to and from the body’s cells and the
blood
Blood
Pressure
Blood Pressure
Systole: maximum pressure formed during a
ventricular contraction
Diastole: minimum pressure during ventricular
relaxation (atrial contraction)
Blood Pressure
Normals
Systolic = 100 – 140
Diastolic = 60 – 90
Hypotension: Systolic < 90
Hypertension: Systolic > 150 and/or Diastolic > 90
Blood Pressure
Factors Affecting BP
Cardiac output
Peripheral resistance
Blood volume
Diseases of the Cardiovascular System
1.
Arteriosclerosis
2.
Atherosclerosis
3.
Hypertension
4.
Ischemic Heart Disease
http://www.argosymedical.com/Circulatory/samples/anim
ations/Myocardial%20Damage/index.html
5.
Cardiac Arrhythmias
6.
Bacterial Endocarditis
7.
Valvular Heart Disease
8.
Congenital Heart Disease
9.
Congestive Heart Failure (CHF)
http://www.argosymedical.com/Circulatory/samples/anim
ations/Congestive%20Heart%20Failure/index.html
Blood
Functions of blood
Transportation
1. Blood carries oxygen and nutrients from digestive
and respiratory systems and delivers them to each
cell.
2. Blood carries waste products from cells to excretory
organs.
a. Carbon dioxide from cells to lungs
b. Other waste products of metabolism to kidneys
Defense against disease
1. White blood cells combat bacterial invasion
2. Antibodies
Components of Blood
Plasma – liquid part of blood. May contain
digested food, metabolic wastes, carbon dioxide,
oxygen, hormones or enzymes.
Formed elements - …..
Formed Elements
▪ Red blood cells (erythrocytes)
Contain hemoglobin (from red bone marrow)
Transport Oxygen from lungs to cells and C02
from cells to lungs
▪ White blood cells (leukocytes)
formed in bone marrow or lymph tissue
destroy invading bacteria
▪ Platelets (thrombocytes)
tiny fragments of bone marrow cells; required for
clotting of blood
Blood Types
▪ The population is divided into four blood groups
called A, B, AB or O. The types are distinguished
by the presence or absence of specific proteins
on the surface of the red blood cells or in the
blood serum.
▪ Blood type is important in transfusion
Antigen and Antibody
Antigens
Antibodies
▪ There are two antigens,
A and B. If you have the
A antigen on the RBC,
then you have type A
blood. When B antigen
is present, you have
type B blood. When
both A and B antigens
are present, you have
type AB blood. When
neither are present, you
have type O blood.
▪ When an antigen is present
on the RBC, then the
opposite antibody present in
the plasma. For instance,
type A blood has anti-type-B
antibodies. Type B blood has
anti-type-A antibodies. Type
AB blood has no antibodies
in the plasma, and type O
blood has both anti-type-A
and anti-type-B antibodies in
the plasma. These
antibodies are not present
at birth but are formed
spontaneously during infancy
and last throughout life.
▪ Type A would have B agglutinins (antibody) in the
plasma.
▪ Type B would have A agglutinins (antibody) in the
plasma.
▪ Type AB would not have agglutinins (antibody) in
the plasma.
▪ Type O would have A and B agglutinins (antibody)
in the plasma.
▪ Universal Donor
▪ Group O
▪ Carries no A or B antigens
▪ Packed and processed units have little antibody
▪ Universal Recipient
▪ Group AB
▪
▪
▪
▪
Patient has no anti-A or anti-B present
Cannot lyse any transfused cells
Beware: other
antibodies may be present
Average Percents
▪ Type O—46%
▪ Type A—40%
▪ Type B—10%
▪ Type AB—4%
A
B
O
Blood Type Calculator
▪ http://www.biology.arizona.edu/human_bio/pro
blem_sets/blood_types/btcalcA_popup.html
▪ http://www.biology.arizona.edu/human_bio/pro
blem_sets/blood_types/inherited.html#calculato
r
inheritance
Rh factor
▪ First found in the Rhesus Monkey
▪ The Rh factor is another protein factor in red
blood cells, separate from A, B, O proteins.
▪ Rh positive blood means the Rh factor (protein)
is present in the red blood cells. (85% of the U.S.
population is Rh positive).
▪ Rh negative blood means no Rh antigen is
present in red blood cells.
▪ The Rh factor is important in transfusion and
pregnancy.
Percentage population
▪ Population
Caucasian
Rh(D) pos
Rh(D) neg
86%
14%
African-American 95%
5%
Oriental
<1%
>99%
Pregnancy and blood type
▪ Father--Rh+ blood
▪ Mother is Rh–
▪ Child could be Rh +.
▪ 1st pregnancy--if the baby is rh +, then there are
no complications.
▪ However, the mother will start to develop
antibodies against the Rh factor
Pregnancy
▪ Second pregnancy, if the child is +, the mother’s
antibodies can cross the placenta and start to
attack the fetus’ blood cells, causing hemolysis.
▪ Hemolysis--breakdown of RBC and the release of
hemoglobin into the plasma which can damage
organs.
▪ This is called erythroblastosis fetalis,can cause
severe anemia, jaundice possibly death.
Inheritance
▪ ABO & RH genes are not linked
▪ ABO & Rh(D) type are inherited independently
For example:
An A Rh(D) pos mother
and a B Rh(D) pos father
could have an O Rh(D) neg child
▪ http://www.biology.arizona.edu/human_bio/pro
blem_sets/blood_types/rh_factor.html
Blood humor