Chapter 19 Blood Flashcards
About 5 liters of ___________, a fluid connective tissue that makes up about 8% of total body weight, circulates through the blood vessels at all times.
Blood
One of the two major components of blood, _____________, is the liquid extracellular matrix of blood.
Plasma
The ____________ of blood include the cells and cell fragments found suspended in plasma.
Formed elements.
What are the 3 types of formed elements in the blood?
Erythrocytes- Red blood cells (RBCs)
Leukocytes- White blood cells (WBCs)
Platelets- small cellular fragments.
List the functions performed by blood
- Exchanging gases - both oxygen and carbon dioxide are transported by blood.
- Distributing solutes-plasma transports ions, nutrients, hormones and wastes, and plays a role in regulating ion concentrations in tissues.
- Performing immune functions-both leukocytes and immune system proteins are transported throughout body in blood.
- Maintaining body temperature- blood carries away heat generated as byproduct of many chemical reactions in body.
- Sealing damaged vessels by forming blood clots-platelets and certain proteins from blood clot; seals damaged blood vessels to prevent blood loss.
- Preserving acid-base homeostasis- pH of blood is maintained between 7.35 and 7.45; remains relatively constant as blood contains several important buffering systems.
- Stabilizing blood pressure- blood volume is major factor in determining blood pressure.
Three distinct layers form when a blood sample is spun rapidly in a centrifuge, these three layers include what?
Top layer- plasma (55% of total blood volume)
The middle layer- Buffy coat (1% of total blood volume)
Bottom layer- erythrocytes/hematocrit (44%)
____________ is a pale yellow liquid whose volume is 90% water.
Plasma
Define viscosity
Refers to the thickness of blood.
Less water in plasma leads to ___________ viscosity and _______________ blood flow.
Greater
sluggish/slow
__________________ forms colloid that makes up about 9% of plasma volume and include albumin, immune proteins (g-globulins), transport proteins and clotting proteins.
Plasma Proteins
Define albumin
A large protein synthesized in the liver. Responsible for blood’s colloid osmotic pressure; draws water into blood by osmosis.
Immune proteins, g-globulins, also known as _______________, are made by leukocytes, components of the immune system.
Antibodies.
_________________ binds to lipid-based molecules that otherwise are incompatible with the mostly water-based plasma, which allows these molecules to use blood as a transportation system.
Transport Proteins
These proteins stop bleeding from injured blood vessels by forming a blood clot with assistance from platelets.
Clotting Proteins.
What enables erythrocytes to transport oxygen and carbon dioxide?
Erythrocytes structure.
Describe the structure of a erythrocyte
The typical erythrocyte is a biconcave disc or a flattened donut-shaped cell that is concave on both sides. This shape increases the surface area of the cell, which is vital to their role in gas exchange.
Mature RBCs are ____________, having lost the nucleus during maturation, and lack most of the other typical cellular organelles.
Anucleate
What is a large protein that consists of 4 polypeptide subunits: two alpha chains and two beta chains?
Hemoglobin
An iron-containing compound in which polypeptides are bound.
Heme group
An iron ion in each heme group is oxidized when it binds to oxygen in regions of high oxygen concentrations which forms a red-colored molecule called what?
Oxyhemoglobin
Hemoglobin releases oxygen into regions, such as tissues surrounding systemic capillary beds, where oxygen concentration is ___________.
Low
In tissues where oxygen levels are low, hemoglobin binds to carbon dioxide forming ______________, which accounts for about 23% of the CO2 transportation in blood.
Carbaminohemoglobin
What is the life span of an erythrocyte?
About 100-120 days
What is the process that takes place in red bone marrow where the formed elements in blood are produced
Hematopoiesis
Formed elements in the blood are formed by _________________ stem cells.
Hematopoietic
__________________ is the specific hematopoietic process that produces erythrocytes from HSCs. This process takes approximately 5-7 days to complete.
Erythropoiesis
Eryhropoiesis begins when Hematopoietic stem cells differentiate into progenitor cells called _______________ (CFUs), which have committed to forming only one single cell type.
Erythrocyte colony forming units.
When erythropoietin, which is secreted by the kidneys, is present, erythrocyte CFUs differentiate into __________________.
Proerythroblasts.
Proerythroblasts develop into ______________, which rapidly synthesize Hb and other proteins.
Erythroblasts
As a erythroblast matures what happens to the nucleus?
It shrinks and is eventually ejected resulting in a reticulocyte
__________________ enters the bloodstream by exiting through pores in the sinusoidal capillaries of the bone marrow.
Reticulocytes
Describe how regulation of erythropoiesis is accomplished
It is accomplished by erythropoietin that triggers a negative feedback loop which maintains the hematocrit within a normal range.
Describe the regulation feedback loop
- Stimulus- Blood levels of oxygen fall below normal
- Receptor- kidney cells detect falling organ levels
- Control Center- kidneys produce erythropoietin and releases hormones into the bloodstream
- Effector/Response- production of erythrocytes increases
- Homeostasis- blood levels of oxygen rise to normal
Describe the death of an erythrocyte
Cells become less flexible as the age and get trapped in the sinusoids of the spleen.
- Spleen macrophages digest erythrocytes.
- Hemoglobin is broken down into amino acids, iron ions, and heme.
- Heme is first converted into waste product biliverdin; can then be converted further to yellowish waste product called bilirubin.
- Iron ions and amino acids are recycled; used to make new hemoglobin in red bone marrow.
- Iron ions are transported back to red bone marrow in bloodstream by protein called transferrin.
- Bilirubin is sent to liver for excretion.
Define Anemia
A common condition defined as decreased oxygen-carrying capacity of the blood.
What are the three primary causes of anemia
Decreased hemoglobin, decreased hematocrit and abnormal hemoglobin
What are the general symptoms of anemia
Pallor (pale skin), fatigue, weakness and shortness of breath
In response to the diminished oxygen-carrying capacity, the body boosts the production of ______________ as the number of circulating reticulocytes increases in the blood, which is caused by different types of anemia.
EPO (erythropoietin)
Severe anemia can cause the heart rate to ___________ in response to the body’s attempt to __________cardiac output to match the demand of oxygen from the oxygen-deprived tissues
Elevate
Increase
What is the most common form of anemia ?
Iron-deficiency anemia
What can cause iron-deficiency anemia?
Caused by inadequate dietary iron intake, reduced intestinal absorption of iron, or slow blood loss. Vitamin B6 deficiency, malnutrition poisoning with certain drugs or heavy metal like lead, and pregnancy can all cause this
This results from vitamin B12 deficiency, which interferes with DNA synthesis of rapidly dividing cells.
Pernicious Anemia
Certain medications or exposure to ionizing radiation can inhibit or stop the production of erythrocytes in the red bone marrow, a condition called _______________ anemia.
Aplastic Anemia
What is the most common cause of abnormal hemoglobin is
Sickle-cell disease
______________ or _____________ are larger than erythrocytes and have a prominent nucleus. This group of cells uses the bloodstream, as transportation, as they generally dont perform their functions within the blood.
Leukocytes or White blood cells
These cells adhere to the walls of blood vessels then squeeze between the endothelial cells to enter the surrounding tissue.
Leukocytes
What two basic categories are leukocytes divided into?
Granulocytes and agranulocytes
Describe Granulocytes
Are readily distinguished by their unusual nuclei, which is a single nucleus composed multiple connected lobes. All cells in this group contain general lysosomal granules as well as granules unique to each type of granulocyte.
Granules are divided into three categories, they are
Neutrophils, Eosinophils and Basophils
Describe Neutrophils
The most common leukocyte, have cytoplasmic granules that absorb both dyes, which stains their cytoplasm a light lilac color. The function of it is - Active phagocytes that ingest and destroy bacterial cells.
Cells that have a uniquely shaped nucleus composed of 3 to 5 lobes
Polymorphonuleocytes (polys or PMNs)
Describe the process of Chemotaxis
Injured cells release chemicals that attract neutrophils, the neutrophils exit the bloodstream and release their granules in the damaged tissue.
Describe the structure of Eosinophils
They have a Bilobed nucleus and appear red due to the uptake of eosin dye
What is the function of eosinophils
They are phagocytes that ingest foreign molecules; they respond to infections with parasitic worms and allergic reactions; they contain chemicals to mediate inflammation
These are the least common of the leukocytes, they have an S-shaped nucleus and appear dark purple due to the uptake of methylene blue dye.
Basophils
What are the functions of basophils
Chemicals in granule mediate inflammation
What is the second most common leukocyte in blood, and contains large spherical nuclei and a light blue rim of cytoplasm when stained?
Lymphocytes
The two basic types of lymphocytes, ______________ and ________________ have similar appearances but different functions, although both cell types are activated by cellular markers found on all cells called _______________.
B lymphocytes
T lymphocytes
Antigens
When activated these cells produce antibodies in which bind to and remove antigens from tissues.
B lymphocytes (B cells)
These cells are activated by specific antigens, do not produce antibodies. These cells have membrane-bound receptors for individual antigens. These cells activate other immune system components and directly destroy abnormal body cells, such as cancer cells or virally infected cells.
T lymphocytes (T cells)
These are the largest cells in the leukocyte family, have a U-shaped nuclei surrounded by light blue or purple stained cytoplasm. These cells only circulate in the blood briefly before they exit the capillaries to enter the tissues where some mature.
Monocytes
What do monocytes mature into ?
Macrophages
What is the role of macrophages?
Phagocytic cells that ingest dead and dying cells, bacteria, antigens and other cellular debris
Define Leukopoiesis
The process in the bone marrow that uses hematopoietic stem cells (HSCs) to form new Leukocytes. HSCs divide and spilt into two cell lines.
Define the myeloid cell lines
Produces most of the formed elements, including erythrocytes and platelets. This cell line differentiates into blast cells, committed to becoming monocytes, called monoblasts and precursor cells called promonoblasts. Granulocytyes are derived from myeloblasts that differentiate into precursor cells called promyelocytes. Band cells, or stab cells, are the final stage, which developed into mature granulocytes that enter the bloodstream.
Describe the lymphoid cell line
Produces lymphoblasts, committed to becoming B and T lymphocytes, which then develop into prolymphocyte precursor cells. B and T lymphocytes mature in different locations, B for bone marrow and T for thymus.
B lymphocytes remain in the ______________, during their maturation
Bone marrow
T lymphocytes migrate from the bone marrow to the ____________ gland in the mediastinum to complete their maturation.
Thymus