Cardiovascular SystemChapters 19 Blood

Anatomy and Physiology

Liberty Senior High

Mr. Knowles

What’s the purpose of the cardiovascular system?

Do all organisms have one?

Let’s model!

Why we need a cardiovascular system!

• Human embryos before 3 weeks are so small, materials are transported by simple diffusion.

• At third week (few mms in length), heart begins beating- first system to function.

• Supplies nutrients to all 75 trillion cells in the body.

What is the cardiovascular system?

Three parts:• Blood – a circulating fluid.

(Chapter 19).• Heart – a pump. (Chapter 20).• Blood vessels – the conducting

pipes (Chapter 21)

Cardiovascular Lymphatic Systems • Fluid leaves the vessel and enters the tissues-

interstitial fluid.• Eventually returns to the vessels.• Lymphatic system has its own vessels.• Used to transport antibodies, white blood cells,

and monitor for infection and cancer.• Cardiovascular + Lymphatic = Circulatory

System.

What is blood?

• Specialized connective tissue with cells in a fluid matrix.

Functions of the Blood• Transport dissolved gases, nutrients,

hormones, and metabolic wastes.• Regulation of the pH and electrolytes of

interstitial fluid. Neutralizes the acids created by metabolism (lactic acid).

• Restricts fluid losses through damaged vessels or at injury sites- blood clots.

Functions of the Blood• Defense against toxins and pathogens-

transports white blood cells that migrate into tissue to fight infection and remove debris. Also, deliver antibodies.

• Stabilize body temperature- absorbs heat from active muscles and distributes to other tissues. Also brings heat to the surface of the skin to lose heat.

Composition of Blood• It is a fluid connective tissue with

an extracellular matrix- plasma + formed elements (cells and cell fragments) = whole blood.

• Plasma + Formed Elements = Whole Blood.

Whole Blood After Centrifugation

Red Blood Cells

White Blood Cells “Buffy Coat”

Plasma

Whole Blood

Centrifuge and

Separate

Formed Elements

37-54%

Plasma

46-63%

Plasma

92 % Water

7 % Plasma Proteins

1 % Electrolytes and other Solutes

Plasma- The Fluid of Life!• Plasma = Plasma Proteins + a Ground

Substance (Serum).• Plasma Proteins:

Albumin- transport fatty acids, maintain isotonic solution.Globulin- immunoglobulin (antibodies).Fibrinogen- form blood clots; becomes fibrin- an insoluble protein.

Plasma

Fibrinogen

Serum Albumin

Globulin

Plasma- The Fluid of Life!• Plasma that has been

allowed to clot will lose its fibrin and other salts like Ca+2.

• Plasma without its fibrin – Serum.

Formed Elements• Formed Elements = Blood Cells + Fragments

suspended in the plasma.• Erythrocytes (Red Blood Cells) – most

abundant (99.9% of all cells); transport of oxygen and carbon dioxide.

• Leukocytes (White Blood Cells) – body’s defense cells. (0.1% of cells).

• Thrombocytes (Platelets) – small, membrane- bound packets of cytoplasm that contain enzymes for blood clot formation.

Erythrocyte

A Normal Blood Smear

Collecting and Analysis of Blood• Blood usually collected at a vein-venipuncture.• Venipuncture- veins are easy to locate, walls of

vein are thinner, pressure is lower heals easier.• Peripheral capillaries- tip of finger, earlobe;

oozing small drop for blood smear.• Arterial Puncture- check for efficiency of gas

exchange.

Properties of Blood• Temperature- 38° C or 100.4° F.

• Viscosity- has a great deal of dissolved proteins in plasma more viscous than water.

• pH – 7.35-7.45; slightly alkaline.

Erythrocytes (RBCs)• “erythros”- red; “cyte”- cell.• RBCs are the most abundant blood cell (99.9%).

25 trillion in average adult. Takes ~ 1 min. to travel circuit.

• Hematocrit- percentage of formed elements in a sample of whole blood. # of cells / microliter of whole blood.

• Has a red pigment-hemoglobin- gives whole blood its color.

RBCs Structure and Function• Highly specialized cell to transport

gases.

• Cell structure is a biconcave disc.

EM of RBCs

A Biconcave Disc

RBCs Structure and Function• Shape provides the RBC with a large surface

area.• Exchange of O2 with the surrounding plasma

must be quick; larger surface area faster the exchange.

• Total surface of all RBCs is 3800 m2 compared to 1.9 m2 of the whole human body.

RBCs Structure and Function• Biconcave shape allows them to form

stacks (dinner plates) – rouleaux inside narrow blood vessels.

• Rouleaux permit the cells to pass through blood vessels without bumping along the walls.

• Do not form logjams or clogs in the narrow capillary.

Rouleaux in a Blood Smear

Rouleaux in Bone Marrow

A Rouleaux

RBCs Structure and Function• Biconcave shape allows the

RBCs to bend and flex when entering capillaries.

• May pass through capillaries ½ the RBC’s diameter.

RBC’s are Highly Specialized Cells

• Have lost all organelles- lack nuclei, mitochondria, and ribosomes.

• Lost these structures to allow more space for hemoglobin and oxygen transport.

• Downside: RBCs unable to divide or repair themselves. Made in bone marrow.

• Short lifespan- 120 days and then must be broken down.

The Destiny of an RBC

Hemoglobin (Hb)

• Accounts for 95% of proteins inside the RBC.

• 280 million Hbs in each RBC.

• Hb binds to and transports O2 and CO2.

The Structure of Hemoglobin

Hb Molecule• Each Hb molecule = four protein chains = 2

alpha chains + 2 beta chains of polypeptides.• Each chain is a globular subunit and has a

heme group.• Heme – a porphyrin which is a ring compound

with an iron in the center.• Iron has a + charge and can bind to O2

(negative).

Hb Molecule

• When hemoglobin binds to O2 – it becomes oxyhemoglobin.

• Very weak interaction; easy to separate.• Fetus uses a fetal hemoglobin- more

readily binds to O2 for more efficient uptake from mother’s RBCs.

Hb Molecule• Alpha and Beta chains bind to CO2

at other sites and transport to lungs. • If hematocrit is low or the amount

of Hb in RBCs is low than normal activity cannot be sustained in tissue- anemia.

Sickle Cell Anemia• Mutations in the beta chains of the Hb

molecule.• When the blood contains abundant O2, the Hb and

RBCs are normal.• But when the defective Hb loses its O2,

neighboring Hb molecules interact and change the shape of the cell- curved and stiff.

• Cannot form rouleaux and may form clots.

Sickle Cell Mutation

Sickle Cell Mutation

Sickle Cell Anemia

Iron-Deficiency Anemia

Malaria in an RBC

Leukocytes (WBCs)• General Properties:

1. Help defend against pathogens, toxins, and damaged cells.2. They have nuclei and other organelles.3. Are made in bone marrow, thymus, spleen, and other lymphatic tissue.

Two Major Groups of WBCs1. Granulocytes- WBCs with

darkly-staining vesicles and lysosomes inside.

a. Neutrophils

b. Eosinophils

c. Basophils

Two Major Groups of WBCs

2. Agranulocytes- do not stain darkly on their interior; have very small vesicles and lysosomes.

a. Monocytes

b. Lymphocytes

Leukocytes• Most WBCs are not in the

circulatory system, but in tissues or organs of the lymphatic system.

• Circulate for only a short time in vessels.

Characteristics of WBCs• Move along the capillaries by amoeboid

movement.• Detect chemicals from injured cells.• Leave the capillary by squeezing through

cells –diapedesis.• Are positively chemotactic in the tissue.• Can destroy things by phagocytosis.

Ameboid Movement and Phagocytosis

White Blood Cell Diapedesis

Infected Cell

Neutrophils• Most abundant of WBCs.• Granules are neutral. Filled with

toxins.• Have a dense, segmented nucleus of

2 to 5 lobes- Polymorphonulear (PMNs).

• Very mobile and arrive at site of infection first.

Neutrophils• Phagocytize “tagged” bacteria.

• Breakdown bacteria with their toxic granules.

• Also, release chemicals to call WBCs to the site- interleukins.

Neutrophils

Eosinophiles• Granules stain with eosin- a red dye.• Only amount 2-4 % of the WBCs.• Have a bilobed nucleus.• Phagocytize bacteria and cell debris.• Use exocytosis to release toxins onto the surface

of large parasites.• Release chemicals that cause allergic reactions.

Eosinophil

Neutrophil and Eosinophil

Basophiles• Stain very darkly. Very small cells.• Very rare in circulation. Usually in tissue.• Release granules of histamine and heparin. • Histamine = permeability of capillaries.• Heparin = blood clotting.• Do not phagocytize.

Basophil

The Last Type of PhilHow’s that

blood working for you?

Monocytes• Larger cells with oval nuclei.• Circulate throughout the blood stream.• Leave the vessel and become

macrophages.• Macrophages phagocytize bacteria, cell

debris, and other foreign elements.• Also, release chemical messengers.

Monocyte

Lymphocytes

• Larger than RBCs and lack deeply-stained granules. Single, large nucleus.

• Abundant in blood. Migrate from blood to tissue through lymph return to blood.

• Most are not found in blood at any one time.

Lymphocyte

3 Kinds of Lymphocytes• T Cells: cellular immunity against foreign tissue

and cells infected with viruses; have killer T cells and helper T cells (CD-4 and CD-8).

• B cells: humoral immunity, produce antibodies (globulin proteins).Also memory cells.

• NK cells: (Natural Killers) large granules of toxin that destroy cancerous cells and some virally-infected cells.

Leukemia

A WBC Review

Platelets

• Thrombocytes (nonmammalian)

• Circulates for 9-12 days

• Cell fragments

Platelet Function

• Transport of chemicals important to the clotting process.

Show me platelet activation!

Platelet Function

• Active contraction after clot formation has occurred–Contain actin & myosin

–After clot forms contraction shrinks clot & reduces size of break in vessel wall

Platelet Function• Formation of a temporary patch

in the walls of damaged blood vessels–Forms a platelet plug: slows the rate of blood loss while clotting continues

Blood Clot

Platelet Production

• Thrombocytopoiesis occurs in the bone marrow

• Bone marrow contains: Megakaryocytes: enormous w/ large nuclei

Platelet Production• Megakaryocytes make proteins,

enzymes, & membranes.

• Shed cytoplasm in small membrane-enclosed packets: Platelets that enter circulation

• Mature megakaryocyte produces 4000 platelets.

Megakaryocyte

What happens when we have an allergic reaction?

Can allergies kill?

An Application

Video: Discovery-Body Story- Allergies