12/30/20

Blood and Blood Vessels

Study Guide

Cardio = heart
Vascular = blood or blood vessels

3 Components to Cardiovascular System:

1. Blood
¡ The transporter

2. Heart
¡ The pump

3. ________________
¡ The highway

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Roles as Regulator and

Protector
¡ Regulates:
¡ ____________
¡ Body temperature
¡ Water content of cells

¡ Protects through:
¡ Clotting
¡ Combats toxins and microbes
¡ White blood cells
¡ Plasma proteins

Properties
¡ Viscous

¡ Slightly alkaline
¡ pH = 7.35-7.45

¡ Temperature = __________

¡ 4-6 Liters
¡ Up to 50% more during pregnancy

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Plasma + Formed Elements =

Whole Blood
¡ Plasma
¡ ____________ liquid with dissolved
substances
¡ 91.5% water, 8.5% solutes (mostly proteins)

¡ Formed elements
¡ Red blood cells (RBCs)
¡ White blood cells (WBCs)
¡ __________________

¡ Hematocrit:
¡ % of total blood volume made up of RBCs

Cellular
Components
¡ Erythrocytes (RBCs)
¡ Tissue oxygenation

¡ Leukocytes (WBCs)
¡ Immunity

¡ ________________ (platelets)

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Hemopoiesis

¡ Production of formed elements

¡ Begins with hemopoietic stem cells in red bone marrow
¡ Pluripotent stem cellsà lymphoid or ________

¡ Lymphoid stem cells

¡ Lymphocytes
¡ Begins in bone marrow, completes in lymphatic tissues
¡ T cells, B cells, and natural killer cells (NK)

¡ Myeloid stem cells—begin and complete in __________

¡ RBCs, platelets, granulocytes, monocytes, mast cells

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Erythrocytes (RBCs)
¡ Biconcave cells
¡ Lack nuclei—all space for oxygen
transport

¡ Contain hemoglobin
¡ Carries _______________
¡ Responsible for red color

¡ Hemoglobin = 4 O2 molecules
¡ Globin (protein)
¡ 4 polypeptide chains
¡ 4 Hemes (one in each chain)
¡ Iron ion in each heme, each binds to 1
oxygen

¡ Life span about 120 days

¡ Macrophages break down to recycle
¡ Iron for new hemoglobin for new RBCs
¡ Non-iron portion of heme converted to
_________________

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Erythropoiesis:
Begins in Bone Marrow
¡ Production of new
__________________

¡ Stimulated by hypoxia (negative

feedback loop)
¡ Releases the hormone,
erythropoietin (EPO-kidney)
¡ Enters bloodstream
¡ Stimulates RBC production (bone
marrow)
¡ Reticulocytes enter bloodstream,
mature in 1 to 2 daysà RBCs
increased!
¡ Oxygen carrying capacity
increases
¡ EPO __________________

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Blood Type
¡ Antigens found on surfaces of RBCs

¡ Blood groups—based on the presence of absence of certain

blood groups.
¡ ABO blood group—A or B antigens
¡ RH blood group—RH antigen

¡ Agglutinins – antibodies in plasma that react with A and B

antigens when mixed.

¡ Transfusions
¡ Whole blood or blood components
¡ Agglutination: Recipient’s antibodies bind to antigens on donated
RBCs. Blood types are incompatible.

¡ Blood types (sub-categories of blood groups)

¡ A+, A-, B+, B-, AB+, AB-, O+, O-

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Rhesus Factor
¡ Discovered in blood of Rhesus monkey

¡ If an Rh+ person receives Rh- blood (of the right

ABO group), no harm.

¡ If an Rh- person receives an Rh+ blood

transfusion, it starts making anti-Rh antibodies.
¡ Incompatible blood transfusion
¡ Sharing needles
¡ Pregnancy
¡ If Rh- mom and Rh+ fetus, can impact future
pregnancies.

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Let’s review!

Myeloid line:
• RBCs
• Platelets
• Some Leukocytes
(innate)
• Eosinophils
• Basophils
• Neutrophils
• Monocytes

Lymphoid line: (acquired)

• Lymphocytes

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White Blood Cells (Leukocytes)

¡ Granular
¡ Eosinophils
¡ Basophils
¡ Neutrophils

¡ Agranular
¡ Lymphocytes
¡ Monocytes/macrophages

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What do they do?

¡ Chemotaxis: happens when something releases

chemicals that attract phagocytic neutrophils
and macrophages.
¡ Neutrophils
¡ Monocytes

¡ Eosinophils: ____________________

¡ Basophils: _______________________

¡ Lymphocytes: ________________________

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Platelets (Thrombocytes)
¡ Thrombopoietin + myeloid stem cells à
Platelets
¡ No nucleus
¡ Chemicals that promote blood clotting

¡ Role of platelets:

1. Induces ______________ to slow blood

flow

2. Form platelet plug to stop further

bleeding

3. Active coagulation cascade to

stabilize plug

4. Initiate clot retraction and dissolution

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Hemostasis
¡ Stopping blood ____________

¡ 3 mechanisms:
1. Vascular spasms

2. Platelet plug formation

3. Blood clotting

¡ Clotting process:

1. Formation of prothrombinase

2. Conversion of prothrombin into thrombin

3. Conversion of thrombin of soluble fibrinogen into insoluble

fibrin.

4. Clot retraction

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Blood Vessels

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Basics
¡ Blood vessels take things where they
need to go
¡ Supplies to _______________
¡ Waste removal

¡ Heart à Tissues à Back to Heart

¡ Arteries
¡ Veins
¡ Capillaries

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Blood Vessel Walls

¡ Most have 3 tissue

layers

1. Tunica interna
(innermost)

2. Tunica _______
(in the middle)

3. Tunica externa
(outermost)

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Arteries and veins differ in the

structure and thickness of their
walls

Vasoconstriction: ___________ muscle layer contracts & ↓ diameter of

vessel
Vasodilation: ____________ muscle layer relaxes & ↑ diameter of vessel

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Vasoconstriction and
Vasodilation:
Practical Application

¡ One method of temperature regulation:

¡ When overheating, blood vessels dilate (become

larger) due to relaxing the tunica media a bit. This
allows more blood flow towards the skin’s surface,
which results in increased heat loss.
¡ When cold: blood vessels constrict (become smaller)
due to contracting the tunica media a bit. This slows
blood flow at the skin’s surface, reducing heat loss.

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Arteries and
¡ Elastic arteries (______________ arteries) Arterioles
¡ Largest diameter arteries in the body
¡ Aorta, pulmonary trunk,
brachiocephalic trunk, subclavian
artery, common carotid artery,
common iliac artery
¡ Thick tunica media à propel blood

¡ Muscular arteries (____________ arteries)

¡ Medium-sized arteries
¡ Brachial and radial arteries
¡ Thick walls à regulators of blood flow
¡ Vasoconstriction and vasodilation

¡ Arterioles (___________arteries)
¡ Blood to capillaries
¡ Influence blood flow
¡ Adjust BP

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Capillaries
(capillus = little hair)
¡ Site of material exchange
¡ Form ‘U-turns’

¡ Thin walls
¡ No TM or TE
¡ One cell layer to pass through

¡ Capillary bed
¡ 10-100 capillaries
¡ Precapillary sphincters
¡ Types of capillary structures

1. Continuous capillaries
2. Fenestrated capillaries
3. Sinusoids

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Diffusion across Capillary

Walls
¡ Occurs most rapidly when
1. Distances involved are __________
2. Concentration gradient is ___________
3. Ions or molecules are __________

¡ Routes of diffusion
¡ Between adjacent cells
¡ Through ion channels
¡ Pores in fenestrated capillaries
¡ Through plasma membrane
¡ Sinusoids

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Venous system

¡ Venules
¡ Veins
¡ Not structured to
withstand _________
pressure
¡ Can adapt to variations
in volume and pressure
¡ Valves - thin fold of
tunica interna that form
flaplike cusps
¡ Point toward the heart
¡ Prevents backflow

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Valves

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Venous return

¡ Blood volume flowing

back to heart through
systemic veins

¡ 3 processes that assist:

¡ ___________ pressure
¡ Skeletal pump
¡ Respiratory pump

Milking action of skeletal pump

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Blood
Pressure
Overview

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Blood Reservoirs
¡ About 64% of blood volume at rest
is in the venous system

¡ Can function as _________________

¡ Can divert blood quickly if
needed
¡ Ex. During hemorrhaging, veins
constrict to counteract the drop in
blood pressure

¡ Chief principal blood reservoirs:

¡ Veins of abdominal organs (liver,
spleen)
¡ Veins of the skin

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Blood Pressure Regulation

¡ Blood pressure - pressure exerted by blood on the walls of
blood vessels when ventricles contract.

¡ Cardiovascular center: in the medulla oblongata

¡ Regulates heart rate, heart contractility and blood vessel
diameter
¡ Receives input from the following:

¡ Parasympathetic impulses decrease heart rate, sympathetic

impulses increase it

¡ ________________– monitor blood pressure, initiate reflexes in

the brain

¡ Chemoreceptors – monitor blood levels of oxygen, carbon

dioxide, and hydrogen ions.
¡ Initiate reflexes that help regulate general systemic blood
pressure.

¡ Hormones (again!)
¡ Angiotensin II, ADH à vasoconstriction, increase BP
¡ Aldosterone à increases blood volume, increase BP
¡ Epinephrine and norepinephrine à increase cardiac
output and vasoconstriction, increase BP
¡ Atrial natriuretic peptide à vasodilation, decrease BP

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RAAS
Renin-angiotensin-
aldosterone system
1. Drop in blood pressure occurs
2. Kidneys detect drop in blood pressure à
secrete renin
3. Renin converts angiotensinogen (from the
liver) to angiotensin I
4. Angiotensin I travels to the lungs where it is
converted into angiotensin II by
angiotensin-converting enzyme (ACE)

5. Angiotensin II causes vasoconstriction of

arterioles
6. Angiotensin II also stimulates aldosterone
to be secreted from adrenal cortex (a
mineralocorticoid)
7. Aldosterone stimulates kidneys to save
water
8. Blood volume and pressure increase

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Other hormones impacting

blood pressure
¡ Catecholamines
¡ Generally ___________ BP
¡ Released from adrenal medulla

¡ Atrial natriuretic peptide (released by cells

of atria)
¡ Lowers BP
¡ Released by cells of atria
¡ Induces vasodilation
¡ Induces salt and water loss via kidneys

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Vascular Resistance

¡ Depends on:
1. Size of ______________
¡ Larger vessels, blood flows quicker, less resistance
¡ Smaller vessels, blood flows slower, more resistance
2. Blood viscosity
¡ Thicker blood flows slower, more resistance
3. Total vessel _________________
¡ Greater length results in greater resistance

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Vascular Resistance

• Friction and Vessel Length

Less Greater
Resistance Resistance

• Friction and Vessel Diameter (lumen size)

Greatest resistance,
slowest flow near
surfaces

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How We Read
Blood Pressure

¡ Blood pressure
¡ Cardiac output
¡ Blood volume
¡ Vascular resistance
¡ ____________ blood pressure
¡ Pressure exerted upon
ventricular contraction
¡ Diastolic blood pressure
¡ Pressure exerted during
________________

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