Lesson 6 - The Circulatory System: Blood Flashcards
leukocytes
WBC’s; blood cells that protect against infection and other diseases
what is the least abundant formed element?
white blood cells
how long do WBCs last in the bloodstream?
only a few hours in the blood before moving to tissues
leukocytes have a _____ nucleus
conspicuous
all WBCs have lysosomes called _____ _____
nonspecific granules
granulocytes have _____ _____
specific granules
specific granules
contain enzymes and other chemicals employed in defense against pathogens
granulocytes (3)
neutrophils
eosinophils
basophils
neutrophil
also called polymorphonuclear leukocytes (PMNs) because of the varied nuclear shapes
what WBC is the first to attack bacteria?
neutrophils
degranulations
occurs when lysosome granules fuse to endosomes containing phagocytized pathogen; occurs in neutrophils
what do neutrophils do in a bacterial infection? (2)
phagocytize bacteria and release antimicrobial chemicals to increase inflammation and attract other phagocytes to the are
what cell type numbers fluctuation greatly depending on the day/night cycle, seasonality, and with the phases of a menstrual cycle?
eosinophils
what cell type increases with parasitic infections?
eosinophils
when do numbers of eosinophils increase? (4)
- parasitic infections
- allergies
- collagen diseases
- diseases of the spleen and central nervous system
what types of things do eosinophils phagocytize? (3)
- antigen-antibody complexes
- allergens
- inflammatory chemicals
what enzymes do eosinophils release? (2)
- enzymes that weaken or destroy parasites such a worms
- enzymes that counter the inflammatory effects of neutrophils and mast cells
what cell type increases with chickenpox, sinusitis, and diabetes?
basophils
what is histamine?
a vasodilator; dilates blood vessels and speeds flow of blood to an injured area
what is herapin?
an anticoagulant; prevents blood clotting and promotes the mobility of other WBCs in the area
both _____ and _____ increase local inflammation initiated by mast cells
histamine, heparin
basophils secrete _____ and _____
histamine, heparin
microphages (2)
neutrophils and eosinophils
what causes pus formation?
a mixture of dead neutrophils, cellular debris, and waste products during the immune response
agranulocytes
lack specific granules and include lymphocytes and monocytes
what things do lymphocytes destroy? (3)
- cancer
- foreign cells (?)
- virally infected cells
lymphocytes present _____ to activate the immune response
antigens (APC)
visual appearance of a stained lymphocyte
- variable amounts of bluish cytoplasm
- ovid/round
- uniform dark violet
visual appearance of a stained basophil
coarse, dark violet granules
when do lymphocyte numbers increase?
diverse infections and immune responses
what do lymphocytes do? (2)
- coordinate actions of other immune cells
- secrete antibodies and provide immune memory
when do monocyte numbers increase?
in viral infections and inflammation
what are monocytes called when the leave the bloodstream and enter tissues?
they transform into macrophages
what do monocytes do?
phagocytize pathogens and debris and act as antigen-presenting cells (APCs)
what do monocytes secrete?
substances that attract immune cells and fibroblasts to an injury site
what do fibroblasts produce?
scar tissue to seal off the injured area
leukopoiesis
production of white blood cells
what happens in the beginning of leukopoiesis?
hematopoietic stem cells differentiate into distinct types of colony-forming units
three types of CFUs
- myeloblasts
- monoblasts
- lymphoblasts
myeloblasts form (3)
neutrophil, eosinophils, and basophils
monoblasts form…
monocytes
lymphoblasts
forma ll types of lymphocytes
red bone marrow stores what type of WBCs? (2)
granulocytes and monocytes
when do monocytes complete development?
when they enter peripheral tissue and become macrophages
when do granulocytes leave the blood?
4-8 hours, live another 4-5 days in tissues
when do monocytes leave the blood?
leave in about 20 hours, enter tissues, become macrophages, and live for a few years
lymphocytes provide
long term immunity
how are lymphocytes recycled?
from blood to tissue fluid to lymph and back to blood
where do all WBCs (except T cells) develop?
in the bone marrow
hematopoietic stem cells produce WBC and _____
RBC
leukopenia
low WBC count, below 5,000 WBC/uL
causes of leukopenia (6)
- radiation
- poisons
- infectious disease
- cancer
- autoimmune disorders
- drugs that destroy/damage bone marrow cells
effects of leukopenia
elevated risk of infection
leukocytosis
high WBC count, about 10,000 WBC/uL
causes of leukocytosis (3)
- infection
- allergy
- disease that increases WBC production
differential WBC count
identifies what percent of the total WBC count consists of each type of leukocyte
leukemia
cancer of hematopoietic tissue, usually producing a very high number of circulating leukocytes
effects of leukemia (3)
normal cell percentages disrupted, impaired clotting, and open to opportunistic infections
types of leukemia (4)
- myeloid leukemia
- lymphoid leukemia
- acute leukemia
- chronic leukemia
myeloid leukemia
uncontrolled granulocyte production
lymphoid leukemia
uncontrolled lymphocyte or monocyte production
acute leukemia (3)
not acute as is over soon
appears suddenly, progresses rapidly, death within months
chronic leukemia
undetected for months, survival time is three yearsc
complete blood count (CBC) (5)
profile of data on multiple blood values:
- hematocrit
- hemoglobin concentration
- total counts for RBCs, reticulocytes, WBCs, and platelets
- differential WBC count
- RBC size and hemoglobin per RBC
hemostasis
cessation of bleeding, involving platelets
platelets
small fragments of megakaryocytes found in bone marrow
thrombocytopenia
platelet deficiency
causes of thrombocytopenia (4)
- autoimmune disorders
- bacteria in blood
- medications
- pregnancy
signs of thrombocytopenia (3)
bleeding along the digestive tract, within skin, and sometimes in the CNS
thrombocytosis
excessive platelets
causes of thrombocytosis (3)
cancer, inflammation, infection
what do platelets contain?
granules filled with platelet secretions
what happens when platelets are activated?
they are capable of amoeboid movement
platelets secrete… (3)
- vasoconstrictors
- procoagulants
- growth factors
procoagulants
clotting factors that promote clotting
platelet growth factors do…
they stimulate mitosis to repair blood vessels
_____ stick together to form _____ _____ to seal small breaks
platelets, platelet plugs
what do platelets chemically attract? (2)
neutrophils and monocytes to sites of inflammations
platelets do… (2)
- initiation formation of clot dissolving enzyme
- phagocytize and destroy bacteria
thrombopoiesis
production of platelets
what triggers hematopoietic stems cells in the bone marrow to become megakaryoblasts?
thrombopoietin
_____ repeatedly replicate DNA without dividing
megakaryoblasts
megakaryocytes
cytoplasm tendrils (proplatelets) protrude into blood sinusoids so as blood flows through it splits off fragments of the megakaryocytes forming platelets
what are fragments of megakaryocytes called?
platelets
the _____ recycles worn out platelets
the speen
hemostasis involves three mechanisms (3)
- vascular spasm
- platelet plug formation
- blood clotting (coagulation)
vascular spasm
starting stage of hemostasis
- immediate protection against blood loss causing constriction of a broken blood vessel
causes of vascular spasm (3)
- some nociceptors directly trigger constriction
- smooth muscle injury
- platelets release serotonin (vasoconstrictor)
step one of vascular spasms
Endothelial cells in the lining of the blood vessel contract and exposes the basement membrane to blood – the basement membrane is usually not exposed to blood
step two of vascular spasm
Endothelial cells release hormones called endothelins to stimulate smooth muscle contraction in blood vessel (promotes vascular spasms) and endothelial, smooth muscle, and fibroblast cell division
step three of vascular spasm
Endothelial cells become “sticky” to seal off the breach in the vessel – allows platelets to attach later on
how long does vascular spasm last?
up to 30 minutes
when does platelet plug formation start?
about 15 seconds after vascular spasms has started
broken blood vessels expose _____ and the _____ _____
collagen, basement membrane
platelet plug formation: step 1
platelet pseudopods stick to damaged vessel and other platelets
platelet plug formation: step 2
pseudopods contract, drawing together a platelet plug
platelet plug formation: step 3
platelets undergo degranulation releasing ADP, Thromboxane A2, and serotonin
platelet plug formation: step 4
continued via positive feedback cycle until the break in the vessel is sealed
endothelium of intact vessels is very smooth and coated with _____
p
prostacyclin
prostacyclin
a platelet repellent to prevent platelet adhesion at non-damaged areas
degranulation
exocytosis of cytoplasmic granules and factors that promote hemostasis
platelet secretions: ADP
what does it do?
attracts and degranulation more platelets
platelet secretions: Thromboxane A2
an eicosanoid, promotes platelet aggregation, degranulation, and vasoconstriction
platelet secretions: serotonin
a vasoconstrictor
factors that limit the growth of the platelet plug include: (5)
- prostacyclin
- inhibitory compounds released by other WBCs
- circulating enzymes break down ADP
- negative feedback from serotonin
- development of blood clot isolates area
prostacyclin
what cells release this?
released by endothelial cells to inhibit platelet aggregation
high levels of serotonin block the action of _____
ADP
coagulation
conversion of fibrinogen to fibrin threads to form the framework of a clot
procoagulants use a _____ _____
reaction cascade
reaction cascade
activate one factor and it will activate the next
when does coagulation start?
about 30 seconds after vascular spasm has started
where are procoagulants usually produced?
the liver
two pathways of coagulation
extrinsic and intrinsic
extrinsic mechanism for coagulation
involves?
involves the blood vessel components, where clotting factors from sources outside the body are released by damaged vessels and perivascular tissues
how is the extrinsic mechanism of coagulation started?
tissue thromboplastin (factor III) from damaged tissues
after factor II is initiated, where does it go>
cascades to factor 7, 5, and 10
which coagulation pathway is faster?
extrinsic, it has fewer steps
intrinsic mechanism
involves humoral (proenzymes) using only blotting factors found in blood itself
what is the intrinsic mechanism of coagulation started?
contact with exposed collagen on ruptured vessel walls by platelets releasing factor 12
what happens after factor 12 is released?
it cascades to factor 11, 9, 8, and 10
both the intrinsic and extrinsic pathways of coagulation require?
calcium
both the intrinsic and extrinsic pathways of coagulation converge on the triggering of?
factor 5 (X), the start of the common pathway
the common pathway of coagulation (3)
- activation of factor 10 leads to production of prothrombin activator
- thrombin converts fibrinogen to fibrin
factor 2
prothrombin
fibrin molecules (monomers) bind to form
fibrin polymers
factor _____ crosslinks fibrin polymer starts
13
how does is the common pathway kept with positive feedback?
thrombin also forms prothrombin activator
clot retraction
platelet pseudopods adhere to fibrin starts and contract, clot becomes come compact withing 30 minutes
overall efficiency of coagulation can be measured with _____ _____ after a 1mm deep incision
bleeding time
platelet-derived growth factor (PDGF) (2)
what secretes this? what does it do?
secreted by platelets and endothelial cells; mitotic stimulant for fibroblasts and smooth muscle to multiply and repair damaged vessels
fibrinolysis
the dissolution of a clot, occurs after tissue repair is completed
factor XII
catalyzes formation of enzyme kallikrein
kallikrein
converts plasminogen into plasmin
plasmin
a fibrin-dissolving enzyme that breaks up clots
controls to prevents coagulation when it isn’t needed: platelet repulsion
platelets do not adhere to prostacyclin-coated endothelium
controls to prevents coagulation when it isn’t needed: dilution (3)
- small amounts of thrombin form spontaneously in plasma
- thrombin is diluted by normal blood flow, preventing clotting
- heart slowing in shock can result in clot formation
controls to prevents coagulation when it isn’t needed: anticoagulants
what are they called?
antithrombin and heparin
antithrombin
deactivated thrombin before it can act on fibrinogen
heparin
what does it do?
interferes with formation of prothrombin activator
where is antithrombin formed?
the liver
where is heparin formed?
what type of cell?
basophils and mast cells
hemophilia
a family of hereditary diseases characterized by deficiencies of one clotting factor or another
what does hemophilia result in?
a failure for blood to clot
hemophilia: physical exertion can cause what? (3)
intramuscular and joint hematomas (clotted blood in tissues) and cause severe pain and eventual joint immobility
what level of clotting factor is enough to prevent symptoms of hemophilia?
half the normal level
how are the most common types of hemophilia inherited?
sex-linked recessive traits
classical hemophilia (hemophilia A)
missing factor VIII (83% of cases)
hemophilia B
missing factor IX (15% of cases)
thrombosis
abnormal formation of a clot in an unbroken vessel
thrombus
an unwanted blood clot in a vessel
where is a thrombus most likely to form, and in who?
the leg veins of inactive people
embolus
a thrombus that has broken away from the vessel wall
infarction
tissue death via loss of oxygen
thromboembolism
traveling blood clots
preventing unwanted clots (2)
use vitamin K antagonists such as coumarin, warfarin
what do coumarin and warfarin do?
they’re vitamin K antagonists that prevent synthesis of clotting factors 2,7, 9, and 10 that require the vitamin
dissolving unwanted clots that have already formed (3)
s.t.h.
- streptokinase
- tissue plasminogen activator
- hementin
streptokinase
enzyme made by streptococcus bacteria that is used to dissolve clots in coronary vessels
tissue plasminogen activator (TPA)
converts plasminogen into clot-dissolving plasmin
hementin
anticoagulant originating from a leech found in the Amazon