BIOS 213 Exam 5

Ch 13 & 14

functions of circulatory system

transportation (respiratory gases, nutrients, wastes)
regulation (hormonal and temp)
protection (clotting and immunity)

blood composition

about 5 liters
arterial blood
venous blood
made of 45% formed elements and 55% plasma

arterial blood

blood leaving the heart
bright red, oxygenated (except for blood going to lungs)

venous blood

entering heart
dark red, deoxygenated (except for blood coming from lungs)

blood plasma

watery portion of blood
dissolved solutes (proteins and other solutes)

formed elements in blood

RBCs, WBCs, cell fragments (platelets)

plasma proteins

albumin, immunoglobulins, fibrinogen, clotting proteins, angiotensinogen
contributes to osmotic pressure by keeping water in the blood

normal blood pH

7.38-7.44

normal hematocrit level

females: 36-46%
males: 41-53%

normal hemoglobin levels

females: 12-16 g/100 mL
males: 13.5-17.5 g/100mL

normal red blood cell count

4.5 to 5.9 million/mm3

normal white blood cell count

4,500-11,000/mm3

albumin

most abundant
creates osmotic pressure to help draw water from tissues into capillaries to maintain blood volume and pressure

alpha and beta globulins

transport lipids and fat-soluble vitamins

gamma globulins

antibodies that function in immunity

fibrinogen

helps in clotting after becoming fibrin
serum - blood without fibrinogen

erythrocyte

RBCs
flattened, biconcave discs
carry oxygen
lack nuclei and mitochondria
around 5 million/mm3
120-day life span
iron heme is recycled from liver and spleen; carried by transferrin in blood to red bone marrow

anemia

abnormally low hemoglobin or RBCs count

iron-deficiency anemia

not enough hemoglobin

pernicious anemia

a lack of intrinsic factor

aplastic anemia

damaged blood cells

leukocytes

WBCs
have nuclei and mitochondria
move in amoeboid fashion
diapedesis (movement through capillary wall into CT)
don't live long
around 5000 to 9000/mm3

granular leukocytes

neutrophils, eosinophils, basophils

agranular leukocytes

monocytes and lymphocytes

thrombocyte

platelets
smallest formed element, fragments of megakaryocytic
lack nuclei
5-9-day life span
clot blood with other chemicals and fibrinogen
release serotonin -> vasoconstriction
130,000-400,000/mm3

neutrophil

54-62%
phagocytic

eosinophil

1-3%
helps detoxify foreign substances
secretes enzymes to dissolve clots
fights parasitic infection

basophil

less than 1%
releases anticoagulant heparin

monocytes

3-9%
phagocytic

lymphocyte

25-33%
provides specific immune responses

hematopoiesis

blood cell formation
occurs in red bone marrow
as cells differentiate, they develop receptors for chemical signals

hemocytoblast

hematopoietic stem cells: give rise to all blood cells
differentiate into either myeloid stem cells or lymphoid stem cells

erythropoiesis

formation of RBCs
red bone marrow produces about 2.5 million RBCs/sec
stimulated by low blood O2 levels
most iron is recycled or comes from diet

hematopoiesis pathway

hemocytoblast
myeloid SC -> RBCs, neutrophils, eosinophils, basophils, platelets, monocytes
lymphoid SC -> T lymphocytes, B lymphocytes, NK lymphocytes

erythropoietin

a glycoprotein secreted by the kidneys that stimulates the production of red blood cells

erythropoiesis pathway

hemocytoblast
proerythroblast
erythroblast
normoblast
reticulocyte
erythrocytes

leukopoiesis

formation of WBCs
cytokines stimulates production of subtypes

cytokines

multipotent growth factor-1
interleukin-1
interleukin-3
granulocyte colony stimulating factor (neutrophils)
granulocyte-monocyte colony stimulating factor (monocytes and esosinophils)

thrombopoietin

stimulates growth of megakaryocytes
released from liver

thrombocytosis

increase in the number of platelets in the blood which tends to cause clots to form

antigens

found on surface of cells to help immune system recognize self cells

antibodies

secreted by lymphocytes in response to foreign cells

ABO system

antigens on erythrocyte cell surfaces

transfusion reaction

if a person receives the wrong blood type, antibodies bind to erythrocytes and cause agglutination

Type A

A antigen
anti-B antibody

Type B

B antigen
Anti-A antibody

Type AB

Both A and B antigens
neither anti-A nor anti-B antibodies

Type O

Neither A or B antigen
Both ant-A and ant-B antibodies

Rh factor

antigen D
Rh-positive has the antigen
Rh-negative does not have the antigen

Rh factor issue in pregnancy

Rh- mother exposed to Rh+ fetal blood produces antibodies
may cause erythroblastosis fetalis in future pregnancies as antibodies cross placenta and attack fetal RBCs
Rh- mother treated with RhoGAM to inactivate ani

hemostasis

cessation of bleeding when a blood vessel is damaged

blood clotting

damage exposes collagen fibers to blood
platelet bind to collagen
Von Willebrand factor holds them there
platelets recruit to form platelet plug
produces vasoconstriction by serotonin and thromboxane A
formation of fibrin protein web

intact endothelium secretes:

prostacyclin and NO
CD39

Prostacyclin and NO

causes vasodilation
inhibits plate

CD39

breaks down ADP into AMP and Pi to inhibit platelet aggregation

formation of Fibrin

fibrinogen is converted to fibrin
intrinsic: activated by exposure to collagen and factor VII
extrinsic: inhibited by tissue thromboplastin (factor III)
Ca2+ and phospholipids convert prothrombin to activate thrombin
fibrinogen -> fibrin
vitamin K needed by liver to make several of clotting factors

dissolution of clots

plasmin digests fibrin
clotting can be prevented with certain drugs

anti-clotting drugs

calcium chelator
heparin: blocks thrombin
coumadin: inhibits vitamin K

right atrium

receives deoxygenated blood from the body

left atrium

receives oxygenated blood from the lungs

right ventricle

pumps deoxygenated blood to the lungs

left ventricle

pumps oxygenated blood to the body

fibrous skeleton

separates atria from ventricles
atria works as one unit, ventricles works as separate units
forms annuli fibrosi rings, which holds the heart valves

pulmonary

between heart and lungs
blood pumps to lungs via pulmonary arteries
blood returns to heart via pulmonary arteries

systemic

between heart and body tissues
blood pumps to body tissue via aorta
blood returns to heart via superior and inferior venae ca

blood pathway

SVC, IVS, coronary sinus
Rt atrium
tricuspid valves
Rt ventricle
pulmonary valve
pulmonary trunk
Rt and Lt pulmonary arteries
pulmonary capillaries
pulmonary veins
Lt atrium
bicuspid valve
Lt ventricle
aortic valve
aorta

atrioventricular valve (AV)

located between atria and ventricles

tricuspid AV

between right atrium and ventricle

bicuspid or mitral AV

between left atrium and ventricle

papillary muscles and chordae tendineae

prevent valve from everting

semilunar valves

located between the ventricles and arteries leaving the heart

pulmonary semilunar valve

between right ventricle and pulmonary trunk

aortic semilunar valves

between left ventricle and aorta

heart sounds

Lub: closing of AV valves, at ventricular systole
Dub: closing of semilunar valves, at ventricular diastole

cardiac cycle

repeating pattern of contraction and relaxation of the heart
systole: contraction
diastole: rel

end-diastolic volume

total volume of blood in the ventricles at the end of diastole

end-systolic volume

amount of blood left in the left ventricle after systole
1/3 of end-diastolic volume

pressure changes during cardiac cycle

ventricles begin contraction, pressure rises, AV valves close (lub); isovolumetric contraction
pressure builds, SL valves open and blood is ejected into arteries
pressure in ventricles falls; SL valves close (dub); isovolumetric relaxation
Pvent < Patria -> AV valve opens
atria contracts, sending blood to ventricles

extrinsic pathway

VII activated by tissue factor
VII complex produced

common pathway

VII and VIII complexes activate X
V complex created
V complex converts prothrombin to thrombin
thrombin converts fibrinogen to fibrin

intrinsic pathway

XII activated by collagen, glass, and others
XI activated by active XII
IX activated by active XI
VIII complex created

dicrotic notch

slight inflection in pressure during isovolumetric relaxation

automaticity

automatic nature of the heartbeat

sinoatrial node

pacemaker
located in right atrium

AV node and Purkinje fibers

secondary pacemakers of ectopic pacemakers
slower rate

pacemaker potential

slow spontaneous depolarization between heartbeats
-40 mV: Ca2+ VGC open -> AP and contraction
repolarization: K+ VGCs open

pacemaker potential modulators

epinephrine and norepinephrine increase cAMP and keep channels open (HCN channels)
ACh slows heart rate

myocardial action potentials

RMP: -85 mV
depolarization by AP from SA node
Na+ VGCs open and potential plateaus at -15 mV
more K+ channels open repolarization
prevents summation and tetanus

intercalated discs

spread APs in heart

SA node

stimulates atrial contraction

AV node

base of right atrium
stimulate ventricles

bundle of His

stimulate ventricles

interventricular septum

divides the bundle of His into right and left branches

Purkinje fibers

stimulate ventricular contraction

conduction of impulses in heart

AP in SA node are quick
AV node is slow
bundle of His speeds things up

repolarization in heart

Ca2+ goes back into SR by Na+-Ca2+ exchanger
myocardium relaxes

Excitation-Contraction Coupling

Ca2+ released
AP conducted along sarcolemma and T tubules
Ca2+ VGCs open
Ca2+ diffuses into cells
Ca2+ release channels open in SR
Ca2+ binds to troponin and stimulates contraction

refractory periods in heart

atria and ventricles cannot sustain a contraction
APs are long, so refractory periods are also long

P wave

atrial depolarization

P-Q interval

atrial systole