Chapter 5 - Vascular Systems in Animals Flashcards
Circulation in Invertebrates
Protozoans
movement of gases and nutrients via simple diffusion within cell
circulation in invertebrates
cindarians
hydra etc.
body walls - 2 cells thick
all cells in direct contact with internal or external env.
no specialized circulatory system
circulation in invertebrates
arthropods
open circulatory system
blood (interstitial fluid) in direct contact with body tissues
circulated by body movements
flows through dorsal vessel, into sinuses
sinuses - exchange of gasses occurs
circulation in invertebrates
annelids
closed circulatory system
to deliver materials to cells not in direct contact with external enivronment
blood confined to blood vessels
dorsal vessel - carries blood to head, coordinated contractions (heart)
aortic loops - five pairs of vessels, fxn as additional pumps, connect dorsal vessel to ventral vessel
no red blood cells
hemoglobin-like pigment dissolved in aq. soltuion
circulation in humans
3 components
musuclar four-chambered heart
network of blood vessels
blood
circulation in humans
process
oxygenated blood pumped from left ventricle to aorta
aorta –> arteries –> capillaries
exchange of gas, nutrients, cellular waste occurs via diffusion across capillary walls
capillaries –> venules —> veins
veins lead deoxygenated blood to heart
veins –> inferior, superior vena cava –> heart
right atrium –> right ventricule –> pulmonary arteries –> lungs
picks up oxygen at lungs
pulmonary vein –> left atrium –> left ventricle
heart
function
driving force of circulatory system
RIGHT: pumps deoxygenated blood to pulmonary arteries to lungs
LEFT: pumps oxygenated blood to superior/inferior vena cava to systemic circulation
heart
structure
atria (atrium, singular):
two upper chambers
thin walled
ventricles:
two lower chambers
extermely muscular
blood vessels
types
arteries
veins
capillaries
arteries
thick-walled, musuclar, elastic
transport oxygenated blood from heart to systemic circulation
pulmonary arteries
thick-walled, muscular, elastic
trasnported deoxygenated blood from heart to pulmonary system
veins
thinly-walled, inelastic
carry deox blood to heart
pulmonary veins
thin walled, inelastic
carry oxygenated blood from lungs to heart
much of blood flow in veins depends on
compression by skeletal muscles during movement
rather than pumping of heart
venous circulation at odds with gravity, thus
larger veins, esp. in legs, have valves that prevent backflow
capillaries
structure
very thin walls
single layer endothelial cells
smallest diamter of all three vessels
red blood cells travel single file
capillaries
function
across which, readily diffuse:
respiratory gases
nutrients
eznymes
hormones
wastes
lymph vessels
definition
secondary circulatory system
distinct from cardiovascular circulation
lymph vessels
function
transport excess interstitial fluid (lymph) to cardiovascular system
keep fluid levels constant
lymph nodes
swellings along lymph vessels containing phagocytic cells (leukocytes)
phagocytic cells (leukocytes)
filter lymph
remove and destroy foreign particles, pathogens
blood
components
plasma
cellular components
blood as a component of the body
avg human - 4-6 L blood
55% liquid, 45% cellular components
plasma
liquid portion of blood
aq. mixture of:
nutrients
salts
respiratory gases
wastes
hormones
blood proteins
e.g. blood proteins
immunoglobins
albumin
fibrinogen
cellular components of blood
erythrocytes
leukocytes
platelets
erythrocytes
fxn and shape
(red blood cells)
oxygen carrying
250 million mlc hemoglobin
biconcave, disk-like shape
hemoglobin
can bind up to 4 oxygen molecules
primary form of oxygen transport
oxyhemoglobin
hemoglobin bound to oxygen
distinct shape of red blood cells allows
increased surface area for gas exchange
greater flex. for movement through tiny capillaries
erythrocytes formed from
stem cells in bone marrow
upon maturation, erythrocytes lose ___ in the bone marrow
nuclei, mitochnodria, membranous organelles
once mature, RBCs circulate blood for ___, after which:
120 days
phagocytized by special cells in spleen, liver
leokocytes
white blood cells
form
larger than RBCs
leukocytes
white blodo cells
fxn
protective
leukocytes
white blood cells
types
phagocytes
macrophages
lymphocytes
phagocytes
(white blood cells)
phagocytize foreign matter and organisms such as bacteria
macrophages
white blood cells migrate from blood to tissue
mature into stationary cells - macrophages
lymphocytes
(white blood cells)
immune response
production of antibodies (B cells)
cytolysis of infected cells (T cells)
platelets
cell fragments
lack nuclei
involved in clot formation
Functions of Circulatory System
blood
transfers oxygen to tissue
waste and CO2 from tissue
platelets
injury repair
leukocytes
main component of immune system
transport of gases
(function of circulatory system)
hemoglobin molecules in erythrocytes bind to oxygen
transport O2 throughout system
hemoglobin also binds to CO2
transport of nutrient
(function of circulatory system)
amino acids, simple sugars absorbed into bloodstream at intestinal capillaries
after processing, transported throughout body
transport of waste
metabolic waste products (water, urea, CO2) diffuse into capillaries from surrounding cells
waste delivered to excretory organs
clotting
reason
(function of circulatory system)
clots prevent extensive blood loss while damaged vessel heals itself
clotting
process
platelets come into contact with exposed collagen of damaged vessel
platelets —> release chemical –> platelet plug + damaged tissue —> thromboplastin + cofactors: calcium, vit. k —> converts prothrombin —> thrombin —> converts fibrinogen —> fibrin
platelet plug
platelets adhere to one another
caused by chemical relased by platelets in contact with exposed collage of damaged vessel
thromboplastin
clotting factor released by platelet plug and damaged tissue
prothrombin
plasma protein
inactive form of thrombin
inactive plasma protein prothrombin converted to active form thrombin by …
clotting factor thromboplastin + cofactors: calcium, vitamin K convert…
fibrinogen
(plasma protein)
converted to fibrin by thrombin
fibrin
threads of fibrin coat damaged area and trap blood cells to form clot
serum
fluid left after blood clotting
immunological reactions
body can distinguish between self and nonself
remembers nonself entities (antigens) previously encountered
antigens
nonself entities
immune system
two specific defense mechanisms
humoral immunity
cell-mediated immunity
humoral immunity
(defense mechanism of immune system)
production of antibodies
cell-mediated immunity
(defense mechanisms)
involves cells that combat fungal and viral infections
lymphocytes
responsible for both humoral and cell-mediated immune mechanisms
humoral immunity
(specific defense mechanism)
production of antibodies
very specific to antigen involved
responsible for proliferation of antibodies following exposure to antigens
immunoglobins (Igs)
aka antibodies
definition
complex proteins that recognize and bind to specific antigens
trigger immune system to remove them
immunoglobin method of attack
(2)
attract other cells (leukocytes) to phagocytize antigen
or
cause antigens to clump together (agglutinate) and form large insoluble complexes - facilitates removal by phagocytic cells
agglutinate
antibodies cause antigens to clump together and form large insoluble complexes
active immunity
(humoral immunity)
produciton of antibodies during immune response
e.g. vaccination
may require weeks to build up
vaccination
mechanism
injected with weak, inactive or related form of particular antigen
stimulates immune system to produce specific antibodies against it
passive immunity
trxfer of antibodies produced by another individual or organism
acquired passively or via injection
e.g. pregnancy
acquired immediately
short-lived - only as long as antibodies circling system
not specific
passive immunity during pregnancy
maternal antibodies cross placenta
enter fetal circulation
confers passive immunity to fetus
gamma globulin
fraction of blood containting wide variety of antibodies
used to confer temporary protection against hepatitis, etc, via passive immunity
nonspecific defense mechanisms
(immunological reactions)
body employs nonspecific defenses against foreign material
types of nonspecific defense mechanisms
(5)
skin
passages
macrophages
inflammation
interferons
- skin
(nonspecific defense mechanism)
physical barrier against bacterial invasion
pores on surface secrete sweat
sweat
(nonspecific defense mechanism)
contains enzyme that attacks bacterial cell walls
- passages
nonspecific defense mechanism
e.g. respiratory tract
lined with ciliated mucous-coated epithelia - filter and trap foreign particles
mucous coated epithelia
line passages (e.g. respiratory tract)
filter and trap foreign particles
- macrophages
nonspecifc defense mechanisms
engulf and destroy foreign particles
- inflammatory response
nonspecific defense mechanisms
iniated by body in response to physical damage:
- injured cells release histamine
- granulocytes attracted to injury
histamines
(inflammatory response - nonspecific defense mechanisms)
release of histamines cause blood vessels to dilate, thereby increasing blood flow to damaged region
granulocytes
(inflammatory response - nonspecific defense mechanism)
attracted to injury site
phagocytize antigenic material
inflammatory response often accompanied by ___
(nonspecific defense mechanism)
fever
- interferons
(nonspecific defense mechanism)
proteins
produced by cells under viral attack
diffuse to other cells –> help prevent spread of virus
allergic reaction
inappropriate response to certain foods and pollen
body forms antibodies and release histamine
rejection of transplants
transplanted tissues or organs detected as foreign bodies by recipients immune system
immune response may cause organ to be rejected
immuno-suppressing drugs
(transplant rejection)
lower immune response to transplants and decrease likelihood of rejection
antigens
macromolecules foreign to host organism
trigger immune response
erythrocytes antigens
(2 types)
characteristic cell-surface antigens
ABO group
Rh factor
Type A
antigen: A
antibodies produced: anti-B
type B
antigen: B
antibodied produced: anti-A
AB
universal recipient
antigen: A & B
antibodies produced: none
O
universal donor
antigen: none
antibodies produced: anti-A & anti-B
if donor and recipient are not matched
(blood transfusions)
erythrocytes will be clumped (rejected) by antibodies in recipient’s plasma
Rh factor
antigen on surface of red blood cell
Rh+ possesses Rh antigen
Rh- lacks Rh antigen
pregnancy and Rh factor
Rh- woman can be sensitive to Rh+ fetus if fetal erythrocytes enter maternal circulation during birth
if woman subsequently carries another Rh+ fetus
anti-Rh antibodies produced during first birth may cross placenta and destroy fetal RBCs
result: severe anemia for fetus
erythroblastosis fetalis
severe anemia for fetus caused by Rh+ sensitivity in mother
mother’s antibodies from first birth may cross placenta and destroy fetal RBCs
erythroblastosis fetalis NOT caused by ABO
anti-A, anti-B CANNOT cross placenta
