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Physiology - CH 19 - Blood


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What are the five functions of the cardiovascular system?
To transport materials to and from cells:
-oxygen and carbon dioxide
-immune system components
-waste products
What type of tissue is blood?
connective tissue
What are the five functions of blood?
-Transport of dissolved substances
-Regulation of pH and ions
-Restriction of fluid losses at injury sites
-Defense against toxins and pathogens
-Stabilization of body temperature
What does fractionation do?
Seperates blood into:
Plasma (fluid + proteins)
Formed elements (cells and solids)
Whare are the three types of formed elements within the blood?
Platelets (cell fragments)
What is the majority of plasma?
What does plasma contain?
-Dissolved proteins
-Other solutes

Similar to interstitial fluid & can exchange with IF

Matrix for other formed elements
What types of materials are exchanged between plasma and IF?
-Small solutes
What is the main difference between Plasma and IF?
Proteins do not pass the endothelial wall of vessels and IF contains none of the proteins
What are the three classes of plasma proteins?
Albumin - Transport (Fatty acids, thyroid/hormone transport)
Glubulin - Antibodies/Immunoglobins, Transport globulines
Fibrinogen - Form clots, form long insoluble strands of fibrin
What is serum?
Liquid part of blood once fibrin has "fallen out"
Where are a majority of the plasma proteins made?
Where are antibodies made?
plasma cells (not the same plasma as blood)
What is the approximate percentage of total body weight due to blood?
What is the majority of formed elements within blood?
Erythrocytes (99%)
What is a hematocrit?
Reports percentage of RBCs in whole blood

Male 40-52%
Female 36-47%
What is the important of RBCs shape and size?
High surface-to-volume ratio:
quickly absorbs and releases oxygen

Discs form stacks:
smoothes flow through narrow blood vessels Discs bend and flex entering

small capillaries:
7.8 µm RBC passes through 4 µm capillary
What are the basics of erythrocytes?
Lack nuclei, mitochondria, and ribosomes

Live about 120 days

Contain hemoglobin for oxygen and CO2 transport
What transports respiratory gases in blood?
What is special about fetal hemoglobin?
Has VERY strong affinity for oxygen and is able to steal oxygen from mothers blood via placenta
What is anemia?
Mematocrit or hemoglobin levels are below normal
What is Hemoglobinuria?
hemoglobin breakdown products in urine due to excess hemolysis in blood stream
What is Hematuria?
whole red blood cells in urine due to kidney or tissue damage
What is hemopoiesis?
Process of producing formed elements of blood by:

Myeloid stem cells
Lymphoid stem cells
What are hemocytoblasts?
Stem cells in bone marrow divide to form:

myeloid stem cells: (become RBCs, some WBCs)
lymphoid stem cells: (become lymphocytes)
What is Erythropoiesis?
-Red blood cell formation
-Occurs only in red bone marrow (myeloid tissue)
-Stem cells mature to become RBCs
What does building a red blood cell require?
amino acids

vitamins B12, B6, and folic acid

Low RBC production due to unavailability of vitamin B12 is pernicious anemia
What stimulates erythropoieses?
Erythropoietin (EPO):

secreted when oxygen in peripheral tissues is low (hypoxia)

due to disease or high altitude
What are the most numerous cells in the body?
Red Blood Cells
How long do red blood cells circulate before being recycled?
Four months
What are red blood cell antigens known as?
What are the four basic blood types?
A (surface antigen A)
B (surface antigen B)
AB (antigens A and B)
O (neither A nor B)
What is the Rh factor?
Also called D antigen

Either Rh positive (Rh+) or Rh negative (Rh—)

Only sensitized Rh— blood has anti-Rh antibodies
What is universal donor?
What is the main purpose of white blood cells?
Defend against pathogens

Remove toxins and wastes

Attack abnormal cells
What are three white blood cell disorders?
Leukopenia: abnormally low WBC count
Leukocytosis: abnormally high WBC count
Leukemia: extremely high WBC count
What are the five types of White Blood Cells?
Which of the white blood cells are non-specific defenses and which are specific defenses?

What are neutrophils?
Also called polymorphonuclear leukocytes

50–70% of circulating WBCs

Pale cytoplasm granules with:
lysosomal enzymes
bactericides (hydrogen peroxide and superoxide)
What do neutrophils do?
Very active, first to attack bacteria

Engulf pathogens

Digest pathogens

Digestive enzymes

Defensins - peptides from lysosomes

Release prostaglandins and leukotrienes

Form pus
What is degranulation?
Removing granules from cytoplasm
peptides from lysosomes
attack pathogen membranes
What are eosinophils?
Also called acidophils

2–4% of circulating WBCs

Attack large parasites
Excrete toxic compounds:
nitric oxide
cytotoxic enzymes

Are sensitive to allergens

Control inflammation with enzymes that counteract inflammatory effects of neutrophils and mast cells
What are basophils?
Are less than 1% of circulating WBCs

Are small

Accumulate in damaged tissue

Release histamine: dilates blood vessels
Release heparin: prevents blood clotting
What are monocytes?
2–8% of circulating WBCs

Are large and spherical

Enter peripheral tissues and become macrophages

Engulf large particles and pathogens

Secrete substances that attract immune system cells and fibroblasts to injured area
What are lymphocytes?
20–30% of circulating WBCs

Are larger than RBCs

Migrate in and out of blood

Mostly in connective tissues and lymphatic organs

Are part of the body’s specific defense system
What are the three classes of lymphocytes?
T Cells
B Cells
Natural Killer Cells
What are T-Cells?
Cell-mediated immunity
Attack foreign cells directly
What are B-Cells?
Humoral immunity
Differentiate into plasma cells
Synthesize antibodies
What are natural killer cells?
Detect and destroy abnormal tissue cells (cancers)
What do all blood cells originate from?
All blood cells originate from hemocytoblasts:
which produce myeloid stem cells and lymphoid stem cells
How do white blood cells develop?
WBCs, except monocytes:
develop fully in bone marrow

develop into macrophages in peripheral tissues
What are the 4 colony-stimulating factors (CSFs)?
Hormones that regulate blood cell populations:

M-CSF: stimulates monocyte production

G-CSF: stimulates granulocyte productionneutrophils, eosinophils, and basophils

GM-CSF: stimulates granulocyte and monocyte production

Multi-CSF: accelerates production of granulocytes, monocytes, platelets, and RBCs
What are platelets?
Cell fragments involved in human clotting system
What is platelet circulation?
Circulates for 9–12 days
Are removed by spleen
2/3 are reserved for emergencies
What are two platelet related conditions?
abnormally low platelet count
abnormally high platelet count
What are three functions of platelets?
Release important clotting chemicals

Temporarily patch damaged vessel walls

Actively contract tissue after clot formation
How does platelet production occur?
Also called thrombocytopoiesis:

occurs in bone marrow
Megakaryocytes - giant cells
Manufacture platelets from their cytoplasm
What are the three stages of hemostasis?
The cessation of bleeding:

vascular phase (vascular spasm/contraction)
platelet phase (Platelet adhesion/aggregation)
coagulation phase (coagulation, fibrinogen -> fibrin)
What is prostacyclin?
Released by platelets during clotting to prevent uneeded clots

Inhibits clotting

Negative Feedback
What is the purpose of a blood clot?
Fibrin network
Covers platelet plug
Traps blood cells
Seals off area
What are the three pathways of coagulation?
Extrinsic pathway:
begins in the vessel wall outside blood stream

Intrinsic pathway:
begins with circulating proenzymes within bloodstream

Common pathway:
where intrinsic and extrinsic pathways converge
What is the common pathway for coagulation?
Activation of Factor X

Forms enzyme prothrombinase

Converts prothrombin to thrombin

Thrombin converts fibrinogen to fibrin
What is the purpose of thrombin?
Stimulates formation of tissue factor

stimulates release of PF-3:
forms positive feedback loop

(intrinsic and extrinsic):
accelerates clotting
What pulls a wound together during healing?
What is fibrinolysis?
Slow process of dissolving clot:

thrombin and tissue plasminogen activator (t-PA): activate plasminogen

Plasminogen produces plasmin: digests fibrin strands

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