Exam 1 Flashcards
What is blood?
Aka “whole blood” it is the major connective tissue in the cardiovascular system. It is a fluid connective tissue.
What are the functions of blood?
Transportation, protection, and regulation.
What is the blood function of transportation?
Blood transports things around the body ie gasses, nutrition/wastes, chemical messengers (hormones), and cells (RBC, WBC, Platelets)
What is the blood function of regulation?
Blood regulates temperature–made possible by its large percent composition of water, pH and ions–the pH range is 7.35-7.45 outside of which denatures proteins and cells, and tonicity–how the environment affects the cells shape which is important because a normal shape is vital for normal function.
What is the composition of blood?
Plasma: 55%
Formed Elements: 45%
What is the composition of formed elements?
Formed elements is another word for cells and cell parts containing 99% hematocrit–erythrocytes, and 1% Buffy Coat–leukocytes and platelets
What is the composition of plasma?
92% Water
1% hormones, waste (CO2 & Urea), nutrients (some O2, glucose and other monomers (amino/fatty acids), and electrolytes (Na+, Ca2+, Cl+)
7% Proteins: 3 most common: Albumin, globulins, fibrinogen
What is Albumin and what is its function?
Smallest, most abundant protein in blood plasma.
Functions to bind to hydrophobic compounds (lipids such as fatty acids and steroids) and prevents osmosis from plasma to tissues keeping water in the plasma, preventing tissue edema, and maintaining the osmotic pressure of blood.
What are globulins and what do they do?
The medium-sized, medium-abundance protein in blood plasma
Alpha and Beta Globulins are transport globulins that bind to and transport lipid soluble vitamins, iron, and lipids
Gamma globulins are immunoglobulins aka antibodies that bind to pathogens.
What are fibrinogens and what do they do?
The largest, least abundant blood plasma protein.
Functions to aid in blood clotting to keep RBC from leaking out of blood vessels
What is the structure of erythrocytes?
Structure: biconcave (indented on top and bottom) allowing for flexibility (bending through bv), and maximization of surface area
What are the components of erythrocytes?
Formed in red bone marrow, erythrocytes lack cell organelles and a nucleus which means that they cannot repair themselves leading to a lifespan of ~120 days (filtered out by spleen or liver)
Have Spectrin- special cytoskeleton protein to make it flexible
Has Hemoglobin (Hb) that fills the area empty from the lack of organelles and nucleus carrying about 250 million Hb molecules per cell
What is the function and structure of hemoglobin?
Hb picks up O2 in th e lungs and releases it to the tissues in a reversible binding reaction
Four globin chains which are polypeptides– big chains of amino acids, that can bind reversibly to small percentages of CO2
Four Heme groups that contain a central Fe +2. This group is what binds reversibly to O2.
Each Hb can carry four O2
What are the characteristics and structure of Leukocytes?
Leukocytes have the ability to move around and sometimes to leave the bv and crawl into a tissue this is called diapedesis
Structure: Have organelles and a nucleus, but have a short life span and is continually produced by red bone marrow
Leukocytes are either granular or agranular
What is the difference between granular and agranular leukocytes and which leukocytes fall into these categories?
With or without visible speckles under the microscope (vesicles responding to dye)
Granulocytes: neutrophils, eosinophils, basophils
Agranulocytes: lymphocytes and monocytes
What is the abundance, function, lifespan, granules and nuclei of a neutrophil?
Abundance: (most common) 50-70%
Function: Phagocytosis (mostly of bacteria) - they are the first responders at bacterial infection
Lifespan: 1-2 days
Granules: contain chemicals to kill bacteria (pyrogen that causes fever)
Nuclei: Multilobed- this is how you ID a neutrophil (cannot really see granules)
What is the abundance, function, lifespan, granules and nuclei of an eosinophil?
Abundance: 1-4%
Function: Cytotoxic (dead cell) sometimes phagocytosis
Lifespan: 6-12 hours
Granules: Reddish granules releasing chemicals in response to parasites which is common in the digestive tract and to reduce inflammation by degrading histamine
Nuclei: Bilobed nuclei
What is the abundance, function, lifespan, granules and nuclei of a basophil?
Abundance: <1%
Function: Inflammation makers
Lifespan: Unknown (1-2 days)
Granules: Release histamine (causes vasodilation to increase blood flow) & heparin (anticoagulant to increase blood flow)
-Responds to allergens and infection
-Moderates later stage inflammation
Nuclei: Hard to see nuclei behind big blue granules
Changes into Mast Cells when leaves blood
What is the abundance, function, lifespan, and nuclei of a monocyte?
Abundance: 2-8%
Function: Large phagocytic cells
Lifespan: 8hrs in blood
Nuclei: Big & fat
Release chemicals to attract fibroblasts
Leaves blood called Macrophages (++ names)
What do fibroblasts do?
Fibroblasts product collagen fibers to surround infected site
What is the abundance, function, and nuclei of a lymphocyte?
Abundance: 20-40%
Function: Acquired immunity- which means that it facilitates responses to specific viruses- reexposure attack from memory.
- Responsible for response to antigens
Nuclei: Huge & round/oval
What are the three types of lymphocytes and what do they do?
Natural Killer (NK) cells: attack cells that lack “self” proteins
T cells: attack foreign/diseased cells
B cells: secrete antibodies that bind to antigens
What is the function and origin of platelets?
Function: in hemostasis (clotting process) to stop the bleed
Origin: Megakaryocyte Huge cells in red bone marrow
-Platelets form from fragments of membrane-enclosed packets of chemicals that flake off the apical surface of the Megakaryocyte
What is hematopoises?
Hematopoiesis is the formation of all formed elements in bone marrow.
What is a hematopoietic stem cell?
A stem cell capable of becoming any formed element.
How does the body know to make Red blood cells?
The red bone marrow is notified by EPO–erythropoietin–a hormone released by the kidneys when they sense low blood oxygen levels.
What does the EPO cause?
The EPO causes hematopoietic stem cells in the red bone marrow to differentiate into pro-erythroblasts–a committed cell that can only turn into a RBC. This turns into an early stage erythroblasts which has lots of ribosomes to make protein (important because protein is a major component of Hb). This turns into late stage erythroblast that has a lot of Hb and ejects its nucleus as it differentiates into a reticulocyte which is released into circulation and its ribosomes breakdown. Once the ribosomes are broken down the cell is an erythrocyte.
Why is erythropoiesis homeostasis important and how is it maintained?
It is important because too many RBC makes blood too viscous.
It is maintained via negative feedback. Kidneys sense high oxygen in the blood and stop secreting EPO.
What nutrients are needed to make erythrocytes and what synthesis are they used for?
Iron: For Hb synthesis
Vitamin B12, Folic Acid: For DNA synthesis during erythropoiesis.
How can we get iron and how/where is it stored in the body?
Iron comes from our diet (meat, vegetables) or from recycles RBC
Iron is either being transported as T-Iron: bonded to the transport protein transferrin, as in the Spleen, small intestine, and plasma
or being stored as F-iron: bonded to ferritin, as in the liver.
What is the life cycle of a erythrocyte?
1) Low oxygen levels in the blood
2) EPO levels increase in the blood
3) RBC are made in the red bone marrow
4) RBC function in the blood stream for 120 days
5) Spleen filters out damaged RBC by macrophages
What happens to the erythrocyte in the spleen?
The Hb is broken into globin and heme
The globin is broken into amino acids which are released into the blood stream
The heme is broken into iron and bilirubin
What happens to the bilirubin once it has been released from the spleen?
Bilirubin is transported to the liver and is made into bile.
Bile is secreted into the small intestine for digestion
-some goes back to the liver via the circulatory system for reuse
-the rest stays in the digestive track and goes into the large intestine
From the large intestine the bile is either excreted as a specific bile byproduct “stercobilin” in the stool or is released into the blood stream as “urobilin” which is filtered out and excreted bia the kidneys giving urine its yellow color.
What happens to the iron once it is broken down in the spleen?
Iron leaves the spleen as T-iron.
the T-iron is mostly brought to the liver and stored as F-iron which will eventually be brought back to the red bone marrow and put into more red blood cells
What is hemostasis? What are the three steps?
All the processes which prevent bleeding when a blood vessel is damages
1) Vasoconstriction: “vascular spasm”
2) Platelet plug: not keep all RBC in but better than nothing
3) Clot formation: stronger more stable structure in place until repair
What happens in vascular spasm?
Damages blood vessel constricts decreasing the lumen so less blood can flow and less can escape triggered by chemical released by damaged endothelium this is the automatic constriction of smooth muscles
It is sustained by chemical released by platelets
What is endothelium?
Endothelium is the epithelial cells lining blood vessels
What begins the platelet plug?
Many substances flow in the plasma while remaining inactivated such as von Willebrand factors and coagulation factors. vWf is activated when exposed to collagen which only occurs in a damaged blood vessel
What is directly below the endothelium in blood vessels?
Connective tissue called subendothelium which is mostly made of collagen fibers
What happens to form the platelet plug once vWF are activated?
Platelets bind to “stick” to activated vWF then platelets aggregate (clump) and platelets release secretions making them more sticky via a positive feedback loop.
What are the platelet secretions?
Platelets contains chemicals even though they do not have organelles.
Platelets secrete serotonin, ADP, Thromboxane A2 (TXA2) and Ca +2
What does serotonin do?
Serotonin causes vasoconstriction to maintain vessel constriction
What does ADP do?
ADP increased platelet aggregation, enlarge platelets, change platelet shape, and cause platelets to become more sticky. ADP is involved in the positive feedback loop.
What does thromboxane A2 do?
Thromboxane A2 causes vasoconstriction and increases platelet aggregation (which is a positive feedback loop)
What does Ca+2 do?
Ca 2+ is not a part of plug formation but in the coagulation cascade that forms the blood clot.
What is the last step of the platelet plug formation?
Platelets contract the size of the platelet plug by activating the actin and myosin in them.
What prevents platelet plugs from occurring or from getting too large?
Secretions from healthy endothelium cells: Prostacyclin (PGl2) and Nitric oxide (NO) prevent platelet secretions.
Platelet plug grows until it reaches an area high in these secretions.
What is the use of the Fibrin clot formation?
This is the long term fix to keep RBCs from leaking out.
What are the two pathways of fibrin clot formation and what do they do?
Intrinsic pathway: factors arising from inside the blood vessel- major factor being Factor XII that is always present in the plasma and is activated by contact with the subendothelium.
Extrinsic pathway: factors arising from damaged tissue outside the blood vessel. Major factor being Tissue Factor (released by damaged tissue outside the blood vessel)
Sese kick off the clot, they activate the coagulation cascade
these factors typically are simultaneously active
What is the coagulation cascade?
A I/E pathway activates factor X (X Xa). Xa reacts with Factor V, Ca +2, and Phospholipids on platelets and converts prothrombin to thrombin
What does thrombin do?
Activates Factor X and Factors in intrinsic pathway (a positive feedback loop: the more thrombin you have the more thrombin you have). Causes an increase in platelet aggregation so they continue to aggregate even while clot is forming. Converts fibrinogen (plasma protein) to fibrin (more cohesive network for cot formation)and converts XIII to XIIIa