Chapter
52/53/57: Cardiovascular System &
Immunity
Circulation/Respiration/Immunity
I.
Circulation: transportation,
regulation & protection. Chapter 52
A.
distribution
of nutrients including oxygen to cells
B.
unicellular
organism to planaria (flatworms): all
cells exchange gas &/or nutrients directly form the environment outside or
from gastrovascular cavity.
C.
Complex
organisms with multiple cell layers must use circulatory system
1.
Open
circulation: (mollusks and arthropods)
a.
central
heart pumps hemolymph into vessels which drain into a cavity.
2.
closed
circulation: blood is continuously in heart and vessels(annelids and all
vertebrates)
a.
arteries: generally carry blood away from heart
b.
veins: generally carry blood to heart
c.
capillaries: are thinnest most numerous blood goes from
arterioles to venuoles.
d.
lymphatic
vessels: carry extra interstitial fluid
D. Function
1.
transport:
a.
respiratory
b.
nutritive
c.
excretory
2.
regulation
a.
hormone
transport
b.
temperature
i.
endotherms: use vasoconstriction/vasodilation to
maintain body temperature
ii.
countercurrent
blood flow: warm blood vessels radiate
heat to nearby cold blood vessels warming their blood which will travel to core
of body. Maintains body temperature
3.
protection
a.
blood
clotting: thrombocytes and other plasma
proteins to cover breaks in vessels
b.
immunity: leukocytes/WBC’s produce antibodies, engulf
invaders, kill invaders.
E.
blood
plasma
1.
metabolites/waste/hormones: dissolved in fluid
2.
ions: sodium/choride/bicarbonate and
calcium/magnesium/copper/potassium/zinc
3.
proteins: produced by liver
a.
albumin
b.
globulins
which carry steroid hormones
c.
fibrinogen
for clotting
d.
serum
= plasma – fibrinogen
F.
Cells
1.
erythrocytes
2.
leukocytes
3.
thrombocytes
(platelets)
G. Blood vessels
1.
arteries: three tissue layers with thicker smooth
muscle layer (endothelium/elastic:smooth muscle:connective tissue)
2.
veins: three layers plus internal valves to reduce
backflow of blood.
3.
Capillaries: one endothelial layer.
H lymphatic
system:
1.
conduct
extra interstitial fluid to lymph nodes (by way of lymph capillaries/vessels)
and/or organs such as spleen thymus.
2.
Spleen
and thymus are germinal centers that produce lymphocytes (T cells and B cells)
for immunity
II.
The
evolution of the four chamber heart:
fish
A.
sinus
venous è
atrium è
ventricle è
conus arteriousus è gills è body cells
B.
limitation: from ventricle to body cells blood moves
slowly reducing oxygen delivery efficiency
amphibian
A.
lungs:
1.
pulmonary
circulation: heart to lungs to heart
2.
systemic
circulation: heart to body to heart
B.
right
atrium è
ventricle è lungs è left atrium è ventricle è body
C.
incomplete
separation of deoxy/oxygenated blood reduce efficiency
D. some amphibians undergo
cutaneous respiration to supplement oxygenation.
Reptiles
A.
have
similar heart to amphibians with a partial separation of the ventricel.
B.
Crocodiles
are a group of reptiles with complete separation è four chambered heart.
A.
four
chambers for complete separation
B.
sinoatrial
node regulates heart beat (remnant of sinus venous)
III.
cardiac
cycle
A.
systole: contraction of ventricles increasing pressure
causing atrioventricular valves to close (lub) semilunar valves open while
blood is forced out of heart
B.
diastole: ventricle is relaxing while AV valves are
opening to allow blood to fill ventricle from atium è atria contracts pushing remaining blood into ventricle.
C.
Measuring
BP: sphygmomanometer cuff closes off
brachial arteryè pressure in cuff is reduced until artery
pressure equals blood pressure è blood is then heard moving
through vessels via stethoscope è this is read as systolic
pressure (top number) è as pressure decreases you can hear the blood mvmt sounds end è this is the pressure when the
ventricle is relaxed diastolic pressure (bottom number). Normal 120/80 hypertension 150/90
D. blood flow & blood
pressure
1.
cardiac
output: volume moved by heart effected
by cellular energy needs
2.
blood
pressure/baroreceptors reflex:
a.
blood
pressure decrease sensed by baroreceptors in aorta è medulla è vasoconstriction of aterioles in
skin/viscera è raising blood pressure.
b.
Blood
pressure decrease sensed by hypothalamus (osmoreceptors sense dehydration) è causing thirst and post. Pituitary to release ADH (antidiuretic
hormone vasopressin) è increase fluid uptake/reduce fluid removal from blood by kidney
c.
Blood
pressure decrease is sensed by kidney (decrease in blood flow to kidney) è Kideny releases angiotensin IIè adrenal cortex secretes
aldosterone è increase kidney reabsorption of Na+ and
water / systemic vasoconstriction
d.
Increase
of blood pressure felt by atrium of heart (due to high blood volume) è heart secretes ANP (atrialnatriuretic hormone) è increases Na+ excretion by
kidney. Completes the negative feedback loop that regulates blood
volume/pressure.
e.
Nitric
oxide gas produced by endothelial cells causes neighboring smooth muscle to
relax è
vessel dilation. (nitroglycerin given to heart patients to
relieve angina)
IV.
Respiration
Chapter
53
A.
the
passive process of respiration (requiring only a liquid environment)
1.
Fick’s
law: determines the rate of diffusion
a.
amount
of surface area (A)
b.
differerences
in gas concentration outside vs. inside (Dp)
c.
distance
gas must cross (thickness of membrane) (d)
2.
maximizing
the rate of diffusion
a.
create
a water current past respiratory surface (cilia beating, fish swimming) è Dp
b.
respiratory
organs that increase surface area and decrease thickness of membrane
B.
Gills
used for respiration
1.
external
gills: larvae of fish & amphibians
a.
disadvantage: must constantly move and easily damaged
2.
covered
gills: bony fish
a.
countercurrent
flow
i.
mouth
opens to let water in, water flows over gills, operculum opens to let water
out.
ii.
Blood
flows through vessels (caps) in opposite direction than water flows past gills.
iii. Blood is always in contact
with water that has higher PO2 than blood PO2
C.
Lungs
1.
Amphibians:
a.
lungs
with inadequate surface area.
b.
Use
positive pressure to move air into lungs (gulp in air, push up lower mouth,
forces air into lungs)
c.
Must
rely on cutaneous respiration to suppliment.
2.
Reptiles:
a.
more
surface area in lungs provides adequate oxygen intake
b.
use
negative pressure by expanding rib cage using musles
3.
mammals:
a. branched
passageway leading to millions of alveoli (respiratory membrane)
4.
birds:
a.
most
efficient respiratory structure
b.
unidirectional
flow of air filling air sacs so oxygenated/deoxygenated don’t mix
D. mechanisms regulating breathing
1.
peripheral
receptors in aorta and carotid bodies sense PCO2 in blood è signal to medulla è increase ventilation.
2.
Central
receptors in brain sense PCO2 in cerebrospinal fluid è increase ventilation.
E.
Oxygen
and carbon dioxide transport
1.
Hemoglobin: four proteins with an oxygen binding iron in
each.
2. Carbon dioxide: travel bound to protein part of hemoglobin or as carbonic acid (CO2 + water) è bicarbonate + H+ (which binds to deoxyhemoglobin)
3. Nitric oxide
a. thought to be bound to cystein on Hb molecule(super nitric oxide is reduced form)
V. immunity (chapter 57)
A. Non specific
1st line of defense
1. skin: barrier, lysozymes, pH of 3-5 due to secretions
2. linings of openings: respiratory=mucus/cilia, digestive=HCl.
2nd
line of defense
3. inflammatory response:
1. release of histamine/prostaglandins
2. causes edema: release of fluids and WBC’s
3. Neutrophils destroy all
4. monocytesèmacrophages engulf pathogen etc.
5. temperature: interleukin-1 released by macrophages cause hypothalamus to reset body thermostat.
a. liver/spleen store iron (reducing RBC) needed for bacterial survival.
b. lizards exhibit immune behaviors. Choose warm temps when sick.
B. Specific
1. Antigen: molecule provoking an immune response.
2. humoral immunity: antibodies in fluid attack “matching” antigen
3. cell-mediated immunity: T cells attack antigen representing cells.
C. T cells (lmphocyte)
1. bone marrow produces leukocytes
2. thymus specializes leukocytes into T cell lymphocytes
3. three types:
a. Helper T: initiate cell mediated response (express antigen)(TH)
b. Killer T: lyse infected by viruses (bind/release perforin/water enters/cell dies) cytotoxic T (Tc)
c. suppressor T: reduce cell mediated response
d. memory T: to circulate forever
4. Cell mediated response
a. MHC surface marker are glycoproteins HLA (human leukocyte antigens)
b. self vs non self recognition
c. magrophages are antigen presenting cells
d. MHCI are on all nucleated cells
e. MHCII are on macrophages, B cells and CD4+ T cells
1. helper T cells (CD4) bind with macrophages (MHCII)
2. Cytotoxic T cells (CD8) bind with target cells/pathogens or pathogen representing cells (MHCI)
f. interleukin-1 is released by macrophages to initiate cell mediated response
g. interleukin-2 activates T/B cells and is secreted by helper T’s
h interleukin-4 stimulates B cell proliferation and is secreted by T’s
D. cells(lymphocyte)
1. antibodies: immunoglobulins (Ig)
b. IgM: promote agglutination
c. IgG: 2ndary response
d. IgD: receptors on b cell surface (unknown job)
e. IgA: saliva and breast milk
f. IgE: promotes histamine release.
A. The evolution race