Download Blood Vessels and Circulation - Mater Academy Lakes High School

The Cardiovascular System
Blood
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Blood
 The circulating fluid or the body is the blood: a specialized connective tissue that
contains cells suspended in a fluid matrix
 Blood has 5 major functions:
▪ _________________________________________________________________
▪ _________________________________________________________________
▪ _________________________________________________________________
▪ _________________________________________________________________
▪ _________________________________________________________________
Blood Composition
 Made of plasma and several formed elements
▪ _________________________________________________________________
 Red blood cells (RBCs) or erythrocytes ________________________________________
 White blood cells (WBCs) or leukocytes function in defense
▪ _________________________________________________________________
 Formed elements are produced through _______________________
Blood Plasma
 90% water
 Plasma has large amounts of proteins
▪ 60% albumin
▪ 35% globulins (________________________________)
▪ 5% fibrinogen (________________________________)
Erythrocytes
 Biconcave discs
▪ 2 important effects on RBC function:
▪ ___________________________________________________________
▪ ___________________________________________________________
 Lose most of their organelles during formation
 Contain hemoglobin (Hb) – _________________________________________________
Erythropoiesis
 _______________________________________
 Hemocytoblasts are blood stem cells
 Phases in development
1. ________________________________________________
2. ________________________________________________
3. ________________________________________________
4. ________________________________________________
5. ________________________________________________
 Reticulocytes then become mature erythrocytes
Blood Types
 Antigens are substances that can bring about an immune response
 The presence or absence of 3 antigens (A, B, and Rh) on RBCs determines blood type
▪ Type A blood – _________________________________
▪ Type B blood – _________________________________
▪ Type AB blood – __________________________________
▪ Type O blood – _________________________________
▪ The terms Rh positive and negative indicates its presence or absence
▪ Rh is usually omitted (blood type reported as A negative/positive, B
positive/negative, etc.)
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Leukocytes
 Make up <1% of total blood volume
 Larger than RBCs and have a nucleus
 ________________________________________________________________________
Granulocytes
 Granulocytes: neutrophils, eosinophils, and basophils
▪ Neutrophils
▪ Most numerous WBCs
▪ ___________________________________________________________
▪ Eosinophils
▪ 2-lobed nucleus
▪ ___________________________________________________________
▪ Basophils
▪ Release heparin (_________________________________) and
histamine (_________________________________________________)
Agranulocytes
 Agranulocytes: lymphocytes and monocytes
▪ Lymphocytes
▪ Crucial to immunity
▪ Two types
▪ ____________________________________________________
▪ ____________________________________________________
▪ Monocytes
▪ Largest leukocyte
▪ ___________________________________________________________
▪ Crucial against viruses, parasites, and chronic infections
Platelets
 Small fragments of megakaryocytes
 ________________________________________________________________________
Hemostasis
 Fast series of reactions for the stoppage of bleeding
 Phases:
1. _________________________________
▪ Cutting the wall of a vessel triggers contraction (called a vascular spasm)
2. _________________________________
▪ Platelets attach to the site of injury. They continue to arrive and stick
forming a platelet plug
3. _________________________________
▪ A blood clot forms sealing off the damaged portion of the vessel
The Heart
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Heart Basics
 Blood flows through a network of blood vessels
▪ Blood vessels are subdivided into a pulmonary circuit (___________________
_______________________________________________) and a systemic circuit
(________________________________________________________________)
▪ Blood travels through these circuits in sequence before re-entering the heart
 Arteries (_____________________) carry blood away from the heart
 Veins (_____________________) carry blood to the heart
 Capillaries are small, thin-walled vessels between arteries and veins that permit
gas/nutrient/waste exchange with the surrounding tissues
 Approximately the size of a fist
 Enclosed in pericardium, a double-walled sac
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Contains 4 chambers (2 for each circuit):
▪ _________________________________________________________________
▪ _________________________________________________________________
▪ _________________________________________________________________
▪ _________________________________________________________________
 When the heart beats, the atria contract first, then the ventricles
Pericardium
 The heart lies within the pericardial cavity and is surrounded by the pericardium
▪ Protects, anchors, and prevents overfilling
 Subdivided into 2 layers
▪ _________________________________________________________________
▪ _________________________________________________________________
▪ Separated by fluid-filled pericardial cavity (decreases friction)
Surface Anatomy
 _________________________ – deflated atrium
 _________________________ – deep groove filled with fat. Marks the border between
the atria and the ventricles
 _________________________ – the pointed tip of the heart
The Heart Wall
 Epicardium—_______________________________________
▪ Covers the outer surface of the heart
 Myocardium
▪ _________________________________________________________________
▪ Forms concentric layers that wrap around the atria and spiral into the walls of
the ventricles
▪ Results in a squeezing/twisting motion that increases the pumping frequency of
blood
 ________________________________________________________________________
Chambers
 Four chambers
▪ Two atria
▪ Separated internally by the interatrial septum
▪ Opens into ventricle via atrioventricular (AV) valve
▪ ____________________________________________________
▪ Receive blood from superior vena cava (_________________________
________________________________) and inferior vena cava (______
__________________________________________________________)
▪ Two ventricles
▪ Separated by the interventricular septum
▪ Blood travels from the right atrium to the right ventricle through an
opening covered by 3 flaps, called cusps (part of right AV valve)
▪ ___________________________________________
▪ Also a left AV valve called the bicuspid or mitral valve
Heart Valves
 Atrioventricular Valves
▪ _________________________________________________________________
▪ When the ventricles contract blood moving back towards the atrium swings the
cusps together, closing the valves
 Semilunar Valves
▪ _________________________________________________________________
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Coronary Circulation
 Arteries
▪ _________________________________________________________________
_________________________________________________________________
▪ _________________________________________________________________
_________________________________________________________________
 Veins
▪ Great and middle cardiac veins carry blood away from the coronary capillaries
▪ Drain into the coronary sinus (large, thin-walled vein)
Heartbeat
 When the entire heart contracts in a coordinated manner so that blood flows in the
correct direction at the proper time
 2 types of cells involved:
▪ Contractile Cells
▪ ___________________________________________________________
▪ Noncontractile Cells
▪ ___________________________________________________________
The Conducting System
 Atria contract first followed by the ventricles
 Cardiac contractions are coordinated by the conducting system
▪ _________________________________________________________________
▪ Made up of 2 non-contracting cells:
▪ ______________________ – establish rate of cardiac contraction
▪ ______________________ – distribute contractile stimulus to the
general myocardium
Electrocardiogram (ECG or EKG)
 ________________________________________________________________________
 Three waves seen during an ECG
▪ P wave: ______________________________________________
▪ QRS complex: ________________________________________________
▪ T wave: ______________________________________________
The Cardiac Cycle
 The period between the start of one heartbeat and the start of the next
▪ Systole (contraction) – ______________________________________________
_________________________________________________________________
▪ Diastole (relaxation) – ______________________________________________
_________________________________________________________________
Phases of the Cardiac Cycle
 Atrial systole
▪ _________________________________________________________________
 Atrial diastole/ventricular systole
▪ Av valves shut
▪ When ventricular pressure exceeds atrial pressure, _______________________
_________________________________________________________________
 Ventricular diastole
▪ Ventricular pressure declines, semilunar valves close
▪ _________________________________________________________________
▪ Both atria and ventricles are now in diastole
Cardiac Output (CO)
 Volume of blood pumped by each ventricle in one minute
 _______________________________________________________________________
▪ HR = number of beats per minute
▪ SV = volume of blood pumped out by a ventricle with each beat
Blood Vessels and Circulation
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Blood Vessels
 ________________________________________________________________________
________________________________________________________________________
 Delivery system of dynamic structures that begins and ends at the heart
▪ Arteries: ______________________________________________; oxygenated
except for pulmonary circulation and umbilical vessels of a fetus
▪ Capillaries: ________________________________________________________
▪ The vital functions of the cardiovascular system occur at the capillary
level: ______________________________________________________
___________________________________________________________
▪ Veins: ____________________________________________________________
Structure of Blood Vessel Walls
 Arteries and veins have 3 layers:
▪ _______________________ – innermost layer
▪ _______________________ – middle layer containing smooth muscle for
contraction (vasoconstriction) and relaxation (vasodilation)
▪ _______________________ – outermost layer, anchors vessel
Arteries
 When traveling from the heart to capillaries blood goes through elastic arteries,
muscular arteries, and arterioles:
▪ ___________________________
▪ Large thick-walled arteries with elastin in all three tunics
▪ Aorta and pulmonary trunk and their major branches
▪ Act as pressure reservoirs—expand and recoil during the cardiac cycle
▪ ___________________________
▪ Deliver blood to body organs and skeletal muscle
▪ ___________________________
▪ Smallest arteries
▪ Lead to capillary beds
▪ Alter blood pressure and rate of flow through dependent tissues
Capillaries
 ________________________________________________________________________
________________________________________________________________________
 Capillaries do not function as individual units but as part of an interconnected network
called a capillary bed
 The entrance to each capillary is guarded by a precapillary sphincter (a band of smooth
muscle)
▪ _________________________________________________________________
Veins
 ________________________________________________________________________
 From capillaries blood flows through the venules to the medium-sized veins to the large
veins and then enters the heart
▪ Large veins includes the 2 vena cavae
Blood Flow
 Factors affecting blood flow:
▪ _________________________
▪ ___________________________________________________________
▪ Largest pressure gradient found in the systemic circuit between the
aorta and entrance to the right atrium (called the circulatory pressure)
▪ Circulatory pressure has 3 components: __________________________
___________________________________________________________
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________________________
▪ ___________________________________________________________
▪ Sources of peripheral resistance:
 _____________________ – resistance of blood vessels to blood
flow. The most important factor in vascular resistance is friction
between blood &vessel walls
 _____________________ – the resistance to flow resulting
from interactions among molecules and suspended materials in
a liquid
 _____________________ – high flow rates, irregular surfaces,
or sudden changes in diameter can upset smooth blood flow,
this is turbulance. It slows flow and increases resistance
Blood Pressure
 The pressure in arteries fluctuates, rising during ventricular systole and falling during
ventricular diastole
▪ Systolic pressure – __________________________________________________
▪ Diastolic pressure – _________________________________________________
▪ The difference between the 2 pressures is the pulse pressure
 ____________________________________________________
Capillary Pressure
 ________________________________________________________________________
▪ Contributes to capillary exchange
▪ Capillary exchange has 4 important functions:
1. ____________________________________________________
____________________________________________________
2. ____________________________________________________
____________________________________________________
3. ____________________________________________________
____________________________________________________
4. ____________________________________________________
____________________________________________________
Venous Pressure
 Venous system requires less pressure than the atrial system
 When standing, venous blood below the heart must overcome gravity. 2 factors help:
▪ Muscular compression – _____________________________________________
▪ The respiratory pump – ______________________________________________
_________________________________________________________________
Cardiovascular Regulation
 3 mechanisms:
▪ _______________________________
▪ Automatic adjustment of blood flow to each tissue
▪ _______________________________
▪ Respond to changes in arterial pressure or blood gas levels at specific
sites
 Baroreceptor reflexes respond to changes in blood pressure,
and chemoreceptor reflexes respond to changes in chemical
composition
▪ _______________________________
▪ The endocrine system releases hormones that enhance short-term
adjustments and direct long-term changes in cardiovascular
performance
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Exercise and the Cardiovascular System
 During exercise, cardiac output and blood distribution change markedly
 As exercise begins 3 main changes take place:
▪ Extensive vasodilation – _____________________________________________
▪ Venous return increases – ____________________________________________
▪ Cardiac output rises – _______________________________________________
 Other changes: cardiac output increases, blood pressure increases, and blood flow is
restricted
Cardiovascular Response to Hemorrhage
 If blood clotting fails (severe injuries, disorders, etc.) the entire system begins making
adjustments
▪ The short-term elevation of blood pressure
▪ ___________________________________________________________
___________________________________________________________
▪ The long-term restoration of blood volume
▪ ___________________________________________________________
___________________________________________________________
___________________________________________________________
Pulmonary and Systemic Circuit Patterns
 They exhibit 3 general patterns:
▪ _________________________________________________________________
_________________________________________________________________
▪ _________________________________________________________________
_________________________________________________________________
▪ _________________________________________________________________
_________________________________________________________________
Systemic Arteries
 ______________________________ – begins at the aortic semilunar valve of the left
ventricle and ends at the aortic arch
 ______________________________ – contains 3 elastic arteries: the brachiocephalic,
the left common carotid, and the left subclavian
 ______________________________ – continuous with the aortic arch and ends at the
diaphragm
Systemic Veins
 ______________________________ – receives blood from the head, neck, upper limbs,
shoulder, and chest
 ______________________________ – collects most of the venous blood from organs
inferior to the diaphragm
 ______________________________ – delivers blood containing __________________
________________________________ to the liver, where the liver cells absorb them
for storage, metabolic conversion, or excretion