The Blood Flashcards
What are three main functions of blood?
-transport
-regulation
-protection
Describe the substances blood transports
-O2 from lungs to tissues
-CO2 from tissues to lungs to be exhaled
-nutrients from the digestive system
-hormones from endocrine cells to target tissues
-heat and waste products of cellular respiration from cells to be exhaled
How does blood regulate body temperature?
-vasoconstriction and vasodilation of blood vessels
-increasing the amount of blood going to skins surface and to sweat glands helps the body to lose heat
How does blood regulate water content in tissues?
as a result of osmotic pressure gradients due to proteins and dissolved ions within.
What type of tissue is blood?
connective
What does albumin do?
-its a carrier protein and shuttles various molecules through the circulation
-maintians blood osmotic pressure
What is the function of fibrinogen?
produce fibrinogen for clotting
What is the function of globulins?
-immunoglobins
-antibodies bind to foreign substances called antigens
-form antibody-antigen complexes
-transport globulins
-hormone binding proteins
-metalloproteins and apolipoproteins
-steroid binding proteins
What is the percentage composure of blood plasma?
over 90% water
7% plasma proteins-created in the liver confined to bloodstream
What is the buffy coat?
WBC (leukocytes) and platelets
Name some cells in the blood
-neutrophil
-erythrocyte
-eosinophil
-platelets
-monocyte
-lymphocyte
-basophil
What substances make up the plasma
-water
-proteins
-nutrients
-hormones
etc
what are the layers of the blood?
-plasma
-buffy coat
-hematocrit
How does homeostatic mechanisms maintain plasma composition?
-if plasma proteins levels drop
-liver makes more proteins
-if blood becomes too acidic during physical activity then respiratory and renal systems kick in to restore PH of the blood to “normal”
What is the structure of erythrocytes?
-biconcave disks
-no nuclei
-haemoglobin
How many molecules of haemoglobin can a single erythrocyte contain?
250 million!!
Define hypotonic, hypertonic and isotonic
isotonic-same solute concentration as the cell
hypo-water moves into the cell by osmosis, higher water potential in cell, low solute concentration (lysis)
hyper-water moves out of cells by osmosis, low water potential in cell, high solute concentration
(crenation)
What are leukocytes?
a type of white blood cell that are involved in our immune response and fight invading pathogens
What are the five types of leukocytes that are grouped according to wether they have granueles or not?
-granulocytes:
-neutrophils, eosinophils, basophils
agranulocytes:
-small lymphocytes
-monocytes
What is the role of neutrophils?
phagocytise bacteria
What is the role of eosinophils?
involved in allergies and they kill parasites
What is the role of basophils?
-also called mast cells
-reside in connective tissue
-release histamine,heparin
-involved in the inflammatory respones
What is the role of lymphocytes?
form plasma cells which produce antibodies
What is the role of monocytes?
phagocytise debris
What is the role of platelets/thrombocytes?
-involved in the blood clotting response
-when a blood vessel is ruptured or damaged they stick to the area of damage to form a platelet plug.
What is the process called that produces erythrocytes?
erythropoiesis
What is the role of the hormone erythropoietin in erythropoiesis?
they stimulate the formation of erythrocytes
What are the three steps of haemostasis?
-vascular
spasm/vasoconstriction
-platelet plug formation
-coagulation
Describe what happens during vascular spams
damaged tissue responds by vasoconstriction which is the contraction of smooth muscle which acts to limit blood loss
-buys time for the other two steps to occur
Describe what happenss during platelet plug formation
-platelets aggregate to form a temporary plug that seal the break in the vascular wall
-when activated platelets become stickier to help the adhesion to the injury site-facilitated by chemical messengers
Why is platelet plug formation a positive homeostatic feedback system?
as more platlets aggregate, more chemicals are released that stimulate more platelets to migrate to the area to aggregate.
What happens during coagulation?
-infiltrating and reinforcing the platelet plug with fibrin threads that act like glue binding all the aggregated platelets together.
-blood clot/fibrin mesh formed
What happens during coagulation after the blood is clotted?
-plasma is without its clotting proteins and forms serum.
-fibrin threads come from dissolved blood proteins formed through a multistage process with clotting factors/ asprocoagulants
What is the product of the intrisic pathway/phase 1 of coagulation?
prothrombin activator
What ions are involved during the enzymatic casacade of coagulation?
ca2+
k+
Give a brief overview of coagulation
stage 1-platelets attach to endothelium
stage 2-platelets start to release fibrin and begin to seal endothelium
stage 3-the fibrin network traps RBC and completley seals the endothelium
Define haematocrit
the ratio of the volume of red blood cells to the total volume of blood
what factors influence haematocrit?
-pregnancy (lowers)
-blood loss (lowers)
-blood transfusion (higher)
-severe dehydration (higher)
medical conditions such as sleep apnea.
When does a transfusion reaction occur?
the recipients plasma antibodies attack the donors red blood cells
What happens during the inital events of transfusion reaction?
Agglunation of foreign red blood cells clog small blood vessels throughout the body.
the next few hours the clumped red blood cells begin to rupture or are destroyed by phagocytes and their haemoglobin is released into the bloodstream
What happens in a severe transfusion reaction?
RBCs are lysed almost immediately
What problems does the events of a transfusion reactions lead to?
-transfused blood cells cant transport oxygen
-the clumped red blood cells im small vessels hinder blood flow to tissues beyond those points
-Can cause kidney shutdown-acute renal failure
What symptoms can transfusion reactions cause?
-fever
-chills
-low BP
-rapid heartbeat
-nausea
-vomiting
-general toxicity
Describe ABO blood groups
based of the prescence or abscence of two agglutinogens, type A and type B
depending on which person inherits the ABO blood group they will either be A, B , AB or O
What is unique to the ABO blood group?
prescence of plasma or preformed antibodies called agglutinins.
agglutinins act against RBCs carrying ABO antigens that are not present on a persons own red blood cells
Describe the RH blood group
-52 named Rh agglutionogens-RH factor
-common types-C, D, E, e
What does Rh + mean?
RBCs carry the D antigen
-can accept positive or negative blood
What does Rh- mean?
RBCs do not carry the D antigen
-can only accept negative blood
