Blood Functions and Components

• Study notes on the cardiovascular system, specifically the blood

Cardiovascular System

• Cells require constant nutrition and waste removal because they are metabolically active
• The heart, blood vessels, and blood make up this system
• This system connects various tissues in the body
• Blood delivers nutrients and picks up waste products; pumped by the heart through blood vessels
• The cardiovascular system transports gases and hormones throughout the body
• It plays roles in the immune response and body temperature regulation

Facts and Figures on Blood

• Blood is a type of connective tissue
• Formed elements make up 45% of blood: Cells and cell fragments
• Plasma is 55% of blood volume and is a liquid matrix
• Total blood volume in women: 4-5 liters
• Total blood volume in men: 5-6 liters
• Blood makes up 8% of the total body weight

Functions of Blood

• Aids in maintaining homeostasis through the following ways:
• Transport of gases, nutrients, and waste products
• Transport of processed molecules
• Transport of regulatory molecules
• Regulation of pH and osmosis
• Maintenance of body temperature
• Protection against foreign substances
• Clot formation

Specific Functions of Blood

• Transports oxygen from lungs to cells
• Transports carbon dioxide from cells to lungs for exhalation
• Carries ingested nutrients, ions, and water from the digestive system to cells
• Transports waste products from cells to kidneys for elimination
• Carries substances made in one body location via the blood to another part for modification and finalization.
• Transports hormones and enzymes to regulate body processes from one body part to another
• Buffers maintain blood pH around 7.35-7.45
• Osmotic composition critical for maintaining normal fluid and ion balance
• Carries warm blood from the body core to the body surface where heat is released
• An important part of the immune system is located within the blood to fight substances like toxins or microorganisms
• Protects against excessive blood loss when vessels are damaged
• It is the first step in tissue repair and returning tissues to function when tissues are damaged

Plasma

• 91% water and 9% other
• Contains proteins, ions, nutrients, gases, and wastes
• Is a colloid

Plasma Proteins

• Produced by the liver or blood cells
• Globulins
• Albumins
• Fibrinogen

Other components of plasma

• Ions: Sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), chlorine (Cl), iron (Fe), hydrogen phosphate (PO4), hydrogen (H), hydroxide (OH-), bicarbonate (HCO3-)
• Nutrients: Vitamins; glucose, AA's, cholesterol, and triglycerides
• Gases: O2, CO2, and N2
• Wastes: Urea, uric acid, creatinine, ammonia salts, bilirubin, and lactic acid
• Regulatory substances

Functions of the the components of plasma

• Water is a solvent and suspending medium
• Ions are involved in osmosis, membrane potential, and acid-base balance
• Nutrients such as vitamins, promote enzyme activity. Remaining nutrients are energy and building blocks
• Regulatory substances such as enzymes that catalyze chemical reactions and hormones that stimulate/inhibit body functions
• Oxygen is required for aerobic respiration
• CO 2 is a waste product of aerobic respiration that can be used as bicarbonate to help buffer blood
• N2 is inert

Globulins

• Alpha globulins protect tissues via inflammation
• They act as a transport protein
• They convert Fe2+ to Fe3+ for transport in transferrin
• Alpha globulins transport hemoglobin from damaged red blood cells
• Beta globulins act as a transport protein
• They are involved in immunity and prevent blood loss
• Most antibodies are gamma globulins involved in immunity

Albumin

• It is partly responsible for blood viscosity and osmotic pressure
• Functions as a buffer and transport protein

Fibrinogen

• Functions in blood clotting

Plasma Waste

• Urea, Uric Acid, Creatinine, and Ammonia Salts are byproducts of protein metabolism excreted by the kidneys
• Bilirubin is a byproduct of RBC breakdown excreted by the liver through bile into the intestine
• Lactic Acid is a byproduct of anaerobic respiration converted into glucose by the liver

Formed Elements

• Red blood cells (erythrocytes)
• White blood cells (leukocytes)
• Platelets (thrombocytes)
• Red blood cells are 700x more than white blood cells
• They are 17x more than platelets
• White blood cells are broken down into two categories:
  • Granulocytes
  • Agranulocytes

Granulocytes

• Basophils
• Eosinophils
• Neutrophils

Agranulocytes

• Monocytes
• Lymphocytes

Hematopoiesis

• Also known as hemopoiesis; it is the production of formed elements
• In embryos formed elements come from: tissues like the yolk sac, liver, thymus, spleen, lymph nodes, and red bone marrow (RBM)
• After birth formed elements come from:
• Confined to RBM with some lymphoid tissue aiding in production of lymphocytes
• Young children almost all bone marrow is RBM
• Adults RBM confined to ribs, sternum, vertebrae, pelvis, proximal femur, and humerus (rest replaced by Yellow bone marrow)

Red Blood Cells

• RBC's are biconcave disks with thicker edges than in the center
• This shape allows for greater surface area and facilitates faster gas movement into the cell
• It allows for bending and folding, permitting easier passage through small blood vessels
• Original cell loses its nucleus and nearly all organelles upon maturation
• Hemoglobin makes up 1/3 of the RBC volume
• Minor components include lipids, ATP, and the carbonic anhydrase enzyme
• Primary function is to transport oxygen

Oxygen and Carbon Dioxide Transport in Blood

• 98.5% of oxygen is linked to hemoglobin; 1.5% dissolved in plasma

• Hemolysis is when the RBC ruptures.

• Hemoglobin must stay within the cell or it will denature and no longer function

• Carbon dioxide transported in 3 main ways:

• 7% dissolved in plasma

• 23% attached to hemoglobin

• 70% transported as bicarbonate ion (HCO3-)

• Carbonic anhydrase enzyme enables the conversion of carbon dioxide and water into carbonic acid which then dissociates into a H+ and HCO3

Hemoglobin

• Consists of 4 PP-Chains and 4 Heme-groups
• Each polypeptide chain (globin) is bound to 1 heme
• There exist 9 hemoglobin types based on amino acid sequences (α, β, γ, σ & embryonic)
• A heme is a red pigment molecule containing iron
• There are 3 types of hemoglobin that exist with different affinities for oxygen: embryonic, fetal, and adult
• Embryonic hemoglobin produced up to 3rd month of development
• By the 3rd month the fetal hemoglobin replaces the embryonic hemoglobin
• After birth 60-90% is adult hemoglobin, by 2-4 years almost exclusively adult hemoglobin
• Each RBC contains 270 million hemoglobin proteins (4 oxygen molecules each)
• There are 20-30 trillion RBC's at any given time, ~25% of all cells, ~100 trillion total

Hemoglobin Iron

• Iron is required for normal hemoglobin function, oxygen binds to the iron molecule within the heme
• Iron ingested in diet
• Exposure to O2, binds one O2 to each Heme (oxyhemoglobin) without (deoxyhemoglobin)
• Amino acids of the globin bind to CO2 as carbaminohemoglobin
• Hemoglobin also binds to nitric oxide (NO), functions as a chemical signal (hormone) that induces smooth muscle relaxation, plays a role in blood pressure with NO

RBC Life and Death

• Lowered blood oxygen prompts kidney to release erythropoietin, stimulating bone marrow and increasing RBC production and blood oxygen levels
• RBC's live for only 110 (female)-120 (male) days
• Without nuclei they cannot produce new proteins or divide, proteins, enzymes, PM components degenerate
• This causes eventual rupture of the cell, it becomes less able to transport oxygen
• Aged, damaged, abnormal RBC's taken to the spleen, liver, lymphatic tissue; macrophages isolate hemoglobin
• Hemoglobin is broken down into heme and globin

Heme and globin

• Globin is broken down into amino acids to make new proteins
• Heme - Fe is then released, converted into biliverdin then to bilirubin, which enters bile and goes into the small intestine
• Iron transferred back into blood or stored for later use

White Blood Cells

• They lack hemoglobin, have a nucleus and protect the body by removing debris
• Inhibit invading microorganisms
• Most motile, exhibiting ameboid movement
• Leave the blood stream and enter the tissue via diapedesis
  • They are thin and elongated, slip between cells of the blood vessel walls
• Exhibit chemotaxis, drawing them to foreign or waste material
• At the site of infections WBC’s accumulate & phagocytize bacteria and dead cells
• Pus is a buildup of dead WBC + bacteria + fluid + cell debris

Granulocyte Breakdown

Basophil

• Nucleus with 2 indistinct lobes, cytoplasmic granules stain blue-purple between 10-12 micrometers
• Release histamine to promote inflammation and heparin to prevent clots

Eosinophil

• Nucleus often bi-lobed, cytoplasmic ganules stain orange-red between 11-14 micrometers
• Releases chemicals that can reduce inflammation, attacks parasites

Neutrophil

• Nucleus with 2-4 lobes connected by thin filaments, cytoplasmic granules stain light pink between 10-12 micrometers
• Phagocytize microorganisms and Ag-Ab complexes
• Lysozyme

Agranulocyte Breakdown

Lymphocytes

• Round nucleus, cytoplasm forms halo around the nucleus, between 6-14 micrometers
• Produces antibodies and other chemicals responsible for destroying microorganisms
• Contributes to allergic reactions graft rejection, tumor control, & reg'n of the im

Monocytes

• Nucleus can be round, kidney shaped, or horse shoe shaped, more cytoplasm than lymphocyte, between 12-20 micrometers
• Phagocytic, transforms into macrophage that phagocytizes bacteria, dead cells, cell fragments, debris within tissue

Platelets

• Platelets are fragments of cells
• They are surrounded by the plasma membrane and containing granules, at ~3 micrometers in diameter
• Surface shows glycoproteins that allow platelets to stick to other molecules

Essential roles of Platelets

• Essential functional roles:
• Forms platelet plugs that seal holes in small vessels
• Promotes formation and contraction of clots; helps seal off larger wounds in bld vessels
• Contains actin and myosin; platelet contraction
• Platelets have a life span of 5-7 days

Hemostasis

• Stoppage of bleeding to maintain homeostasis.

The 3 Major Steps of Hemostasis

• Vascular Spasm
• Platelet Plug Formation
• Coagulation.

Vascular Spasm

• The mechanism to help slow blood flow
• Temporary constriction of vessel blood
• Produced by Nervous System Reflexes via muscle contraction
• Produced by Chemical Signals via Ex/ platelets releasing thromboxanes

Platelet Plug Formation

• Platelets accumulate to seal breaks
• Platelet Adhesion:
• von Willebrand factor (vWF) binds platelets to collagen in damaged tissue attaching platelets to damaged surface
• Platelet Release:
• Bound platelets release ADP, thromboxanes, & other chemicals which active other platelets
• Platelet aggregation
• Activated platelets express fibrinogen receptors that bind the plasma protein fibrinogen, which links plates together
• Activated platelets express the factors necessary for clot formation

The Formation of Blood Clots

• Occurs when blood vessels are severely damaged
• Blood clot is a network of protein fibers that trap blood cells, platelets, and fluids
• Series of complex reactions involving multiple coagulation factors Intrinsic pathway:
• Extrinsic occurs so chemicals are released Factor Activation begins an with factor VII
• Tissues release thromboplastin/tissue factor(TF)/F3
• The tissue factor converts inactive forms of the factors into activated forms, beginning the cycle

The Intrinsic and Common Pathways

• the extrinsic pathways convert fibrinogen to fibrin.
• Intrinsic Pathway:
• The intrinsic begins with factor XIII in the process
• This in turn triggers a number of reactions that lead to the activation of factor the common pathway to occur. Coagulation Factors assist the Intrinsic Pathways.

Control of Clot Formation

• Clotting out of control homeostasis wouldn't maintained and it would lead to death
• Blood has several anticoagulants to prevent unwanted clotting via inhibition of clotting factors: Examples:
• Antithrombin the protein comes from liver that inhibits protein from releasing.
• Prostacyclin can counteract pro protein reducing to vasodilatation that stimulate the release of platelets factors
• Heparin: can be used to inject with antithrombin it cannot active protein.

Clot Retraction & Dissolution in Hemostasis

Clot retraction is a formed clot begins condenses into denser compact structure

• a part of the tissue contraction begins by activating cause reactions -Serum will also be squeezed out with plasma proteins:
• Plasma- without Fibrinogen + Factors
• The consolidation of pulls helps prevent reduces damages and speeds recovery:

Thrombolysis in Hemostasis

• Thrombolysis, the process which forms clot it is dissolved in the few months:
• Plasminogen: by activate it to cause it to hydrolyzes clot
• Activated in thrombin by F12
• the lysing that can occur by activate process release.

Blood Clot Grouping

• • Transfusion* where blood and cells can flow or can transfer
• Infusion: where the fluid need to get transfer through Saline

Antigen/ Antibody Relations

Antigen (Ag): Located outside within cells Ab are protein antibodies within blood can determine antigens that come to attack. - Ab's are protein from cells that when attached will causes Ag's to activate proteins

• ABO- bloods occur by a - Only, b , or antigens or non can appear. This cause many complications that body cannot be to the antigens

Hemolytic Relations

• Rh negative moms need a shot in RhoGan that can release or protect it by being by negative
• Rh + moms can cause an problem and attack babies after birth or attack when in system for both the mother and the fetus.

Explore the key functions of blood, including its role in temperature regulation and pH balance. Test your knowledge of blood components such as plasma, red blood cells, and white blood cells. Learn about the fate of heme and the role of fibrinogen.