MCAT Biology Ch9: The Cardiovascular System Kap Flashcards
CVS consists of
muscular 4 chambered heart
blood vessels
blood
heart
two pumps
each side made up of two chambers: atrium and ventricle
4 square chambers
muscular organ
walls composed of cardiac muscle (only in heart) of varying thickness
right heart
accepts deoxygenated blood => pulmonary arteries => lungs
pumping blood to lungs via pulmonary circulation
right heart => lungs => lower resistance => lower pressure
left heart
pulmonary veins => receives oxygenated blood from lungs => aorta => body
pumps blood to all tissues by systemic circulation
more muscular => higher pressure => over greater distances against higher resistance
atria
thin walled
blood received here before moving to ventricle
branch into arterioles
ventricle
more muscular than atria
does actual work of pumping blood out of the heart (to body or lungs)
aorta
largest artery in body
major arteries (coronary, common carotid, renal) divide blood flow from here to different peripheral tissues.
arterioles
ultimately lead to capillaries
capillaries
perfuse to tissue
join together into venules
venules
these join into veins
inferior and superior vena cavae
deoxygenated blood travel through veins to these
largest veins in the body
carry blood to right atrium
right atrium
pumps blood into right ventricle
right ventricle
blood into lungs via pulmonary arteries for gas exchange
lungs
when blood leaves through pulmonary vein, goes to left atrium
CVS pathway
left atrium => left ventricle => aorta => arteries => arterioles => capillaries => venules => IVC and SVC => right atrium => right ventricle => pulmonary arteries => lungs => pulmonary veins => left atrium
portal system
some cases, blood passes through two of these, which are connected by venules, before returning to heart
two types of portal systems
hepatic and hypophyseal portal system
hepatic portal system
connects vasculatures of intestines and liver
hypophyseal portal system
in the brain connects vasculatures of hypothalamus and pituitary gland
left ventricle
thickest in the heart
valves
blood flow in one direction
blood flow in one direction
prevent backflow into atria and ventricles
heart beats by ventricular contraction
AV values
between atria and ventricles
tricupsid valve
right AV, three leaflets
bicupsid/mitral valve
left AV, 2 leaflets
semilunar valve
each ventricle protected by this
pulmonary
right semilunar valve; between right ventricle and pulmonary arteries
aortic
left semilunar valve, separates the left ventricle from aorta
diastole
prevent backflow of blood from pulmonary arteries and aorta into ventricles during ventricular contraction
heart is relaxed, semilunar valve closed, and blood from atria is filling ventricles.
systole
AV valves prevent backflow from ventricles into atria during contraction
ventricular contraction and closure of AV valvues occur and blood pumped out of ventricles
LAB RAT
left atrium bicupsid
right atrium tricupsid
contraction
of ventricular muscle generates the higher pressure of systole, whereas their relaxation during dias. causes pressures to dec.
the elascitiy of wall of large arteries which stretch out to receive vol of blood from the heart to maintain sufficient pressure while ventricular muscle are relaxed.
if weren’t for elasticity of large arteries => dias. blood pressure (gauge pressure) plummet to zero => wouldn’t survive long
s1
two AV valves close
s2
two semilunar valves close
cardiac output
total blood vol pumped by the ventricle in a min.
product of heart rate and stroke volume
human = 5L/min
depend on size, age, and cardiovascular and systemic health
rest or exercise => ANS will dec. (parasymp) or inc. (symp.) cardiac output
ANS regulates this by inc. or dec. the heart rate
heart rate
beats per min
stroke volume
vol of blood pumped per beat
cardiac muscle
coordinated, rhythmic contraction of this originates in an electrical impulse generated by and traveling through a pathway formed by four electrically excitable structures
- SA node
- AV node
- bundle of His (AV bundle)
- Purkinje fibers.
myogenic activity
impulse
initiation occurs at SA node, generating 60-100 signals per min w/ any neural input => small collection of cells in wall of right atirum
depolarization wave spreads from SA ndoe => two atria contract simul. => atrial systole (contraction) inc. in atrial pressure => more blood pumped into ventricles (atrial kick, 5-30 % of cardiac output) => signal at AV node => signal delayed here => ventricle fill completely before contract => bundle of His (in interventricular septum (wall) and Purkinje fibers => electrical signal through ventricular muscle => ventricular contraction
SA node
intrinsic rhythm of 60 to 100 signals/min
stress, exercise, excitement, surprise => rise above 100
cardiac contraction influence
parasymp. and symp
parasympathetic
rest and digest
neurotransmitters slow heart via vagus nerve
sympathetic
fight or flight
neurotransmitter speed up heart rate
vagus nerve
neurotransmitters slow heart this
three major types of vessels
arteries, veins, and capillaries
arteries
strong
thick-welled
carry blood away from heart to lungs and other parts
most contain oxygenated blood
ONLY pulmonary arteries and (fetal) umbilical arteries carry deoxygenated blood
same components, diff prop, same type of cells
more smooth muscle than veins
high elasticity => high resistance to flow of blood => left ventricle generate at high pressure
fill w/ blood => elastic recoil from walls => high pressure => force blood forward =>
veins
thin-wallled
inelastic vessels
blood to heart
deoxy blood, EXCEPT pulmonary and umb. vessels,
same components, diff prop, same type of cells
capacitive => carry large amounts of blood since then, inelastic walls than stretch out easily and don’t recoil (3/4 blood)
flow up, against gravity; prevents backflow by:
- inelasticity: larger veins one way valve => shut => prevent backflow
- thinner/absent layer of smooth muscle: skeletal muscle surrounds large veins => squeeze veins as muscle contract => blood against gravity
- if blood clot in vein => dislodged => through heart into pulmonary vasculature => stuck in small vessel
capillary
single endothelial cel layers => exchange of nutrients and gases
delicate
punch => erythrocyte escape to interstital space
small => blood travel in single file
Two compartments of blood
55% liquid, 45% cells
plasma
liquid portion of blood, an aq. mix. of nutrients, salts, resp gases, hormones, and blood proteins
components of cell compartment
erythrocytes, leukocytes, platelets
erythrocytes
for o2 transport
not dissolved in cytoplasm (nonpolar, low solub in aq. environment)
contains hemoglobin protein
biconcave disk shape:
- travel through tiny capillaries
- inc. cell’s SA => greater gas exchange
mature => lose nuclei, mito, and other mem. organelles
form and mature in bone marrow before released into circulation
- loss organelles => max. amount of hemoglobin for gas exchange
- no mito => rely on fermentation for ATP production
live about 120 days
spleen and liver phagocytize them for recycled parts
leukocytes
form in bone marrow
less than 1 percent total blood vol (500-1000)
inc. during infection
crucial part of immune system, defense against pathogens
platelets
cell fragments derived megakaryocytes
clot blood
conc. of 200,000-500,000 per mL
hemoglobin
can bidn 4 molecules of O2 in RBC
5 basic types of leukocytes
neutrophils
cosinophils
basophils
lymphocytes
monocytes
2 class of leukocytes
granulocytes and agranulocytes
granulocytes
neutrophils, cosinophils, basophils
cytoplasmic granules are visible under microscope
having compounds that are toxic to invading microbes
involved in inflammation rxns, allergies, pus formation, destruction of bac and parasites
agranulocytes
lymphocytes
monocytes
lymphocytes
important in specific immune response
some involved in immediate fight against infection, while others in long term memory bank in pathogen recognition
learn from experience => lightning fast response
receive vaccine
specific immune response
body’s targeted fight against particular pathogens such as viruses and bacteria
lymphocyte maturation locations (3)
spleen or lymph nodes => B-cells
thymus => T cells
B cells
antibody generation
T cells
kill virally infected cells
activate other cells
macrophage
monocytes that phagocytize foreign matter like bacteria
marrow => bloodstream => tissue outside of vascular system
microglia
macrophages in brain are called this
megakaryocytes
breakup of cells known as these; cell fragments (platelets) derived from these
HIV
loss of certain subset of T cells known as helper T cells => prevents generation of immune responses against opportunistic infections
antigen
surface proteins expressed by a cell may initiate an organism’s immune system
two major antigen families
ABO anigens and Rh factor protein
relative to blood groups
ABO Group
three alleles for blood type
A and B are codominant
naming based on presence or absence of protein variants
foreign antigens recognized by antibodies
O blood cells
express neither variant => no immune response, regardless of recipient’s blood type
universal donor
produce both antibodies for A and B
universal recipients
AB blood
Rh factor
surface protein
\+ = presence (dominant) - = absence
erythroblastosis fetalis
Rh- mom and Rh+ kid => mom antibodies => 2nd preg => anti across placenta and attack fetal blood cells => hemolysis of fetal cells
medicine (passive immunization) prevents this
Function of CVS
- RBC and plasma=> transport compounds => to and from body’s tissue
- prod. of diff. types of leuko + delivery of immune cells to fight against localized or systemic pathogens => immunity
- platelets and clot formation => repairing damaged vessels
two major gases transported in blood
O2 and CO2
oxygen
from lungs to tissue
carried by hemoglobin in blood => prosthetic heme group bind to O2 (actual binding by central Fe) => redox
O2 saturation decreases when hemoglobin more readily giving up O2
cooperative binding
1st o2 binds to heme => conform shift in hemoglobin from taut to relax => inc. hemoglobin’s affinity in O2 => full => remove one O2 => shift => dec. affintiy
sigmodial
allosteric effect (due to quaternary structure)
CO2
primary waste prod. of cell resp
nonpolar => low solub. in aq. plasma => small % transported in blood to lungs is dissolved in plasma;
vast majority in blood as bicarbonate
-CO2 in RBC => enzyme carbonic anhydrase => combo CO2 and H20 = > carbonic acid => disso. H and bicarbonate anion (high solub) => effective transport cell resp waste prod. to lungs for excretion => formation of ions can be reversed once blood reaches alveolar capillaries in lungs
lower affinity on hemoglobin than O2
conc. of free protons in blood affects pH
high energy demand => inc. rate of cell resp. and o2 supply => higher cell metabolism => PCO2 => lactic acid => dec. pH (inc. proton con => shift right (Bohr))=> signal hemoglobin that tissue needs more oxygen to metabolic active tissue
link between pH homeo and resp and renal systems
WA and CB (buffer) => min. dramatic shift in pH
carbonic acid/bicarbonate
pH of blood = 7.4, alkaline
metabolic or respiratory disturbances => pH down (acidosis) or up (alkalosis)
resp. rate rise or fall => inc. or dec. amount of CO2 gas excreted
kidney => inc or dec. amount of bicarbonate ion secreted into nephron filtrate
acidosis => resp rate inc. => reduce systemic PCO2 => shift reversible left => dec. in H ion conc. (increase in pH)
list of transport of nutrients and waste
carbs and AA
fats
wastes
carbs and AA (transport of nutrients and waste)
absorb in small intestine capillaries => hepatic portal system => systemic circulation
fats (transport of nutrients and waste)
absorbed into lacteals in small intestine => bypass hepatic portal circulation => thoracic duct => systemic circulation => blood stream => packaged into lipoproteins (water soluble)
wastes ((transport of nutrients and waste))
Co2, ammonia, urea
down conc. gradient from tissue into capillaries => blood into excretory organs => waste products filtered or secreted for removal from body
two pressures gradients essential for maintaining proper balance of fluid vol. and solution conc. in interstitium
hydrostatic and oncotic (osmotic) pressures
opposing
gradients
…
hydrostatic pressure
arteriole end of cap => hydrostatic pressure (by contraction of heart and elasticity of arteries, measured upstream in large arteries as BP) is relatively high =>
force per unit are that blood exerts against vessel walls.
capillaries leaky => fluid forced out of bloodstream into interstitial space of tissues (carry nutrients) => pressure drops => venule end of capillary bed, pressure dropped below oncotic pressure
lower pressure in capillaries since can’t handle such high pressure
oncotic pressure
osmotic pressure generated by conc. (plasma proteins) of particles in plasma compartment
constant osmotic/oncotic along capillary, as nutrients filter out and wastes filter in at relatively equal rate
exerts inward force and draws fluid, nutrients. and wastes out of tissues => bloodstream
starling forces
balance of opposing pressure (hydrostatic and oncotic (osmotic) pressures)
too much/little fluid in tissue => imbalance
excess fluid in interstitium => edema
block of lymph nodes => edema
some interstitial fluid => lymphatic system => lymphatic fluid => thoracic duct => returns to central circulatory system
clotting
prevents loss of blood
platelets contact w/ exposed collagen => release (clump together) thromboplastin => prothrombin => thrombin (help from enzymatic cofactors Ca and K) => fibrin (from fibrinogen)
genetic diseases like hemophilia
thromboplastin
one of important chemicals this clotting factor they release is this
thrombin
converts fibrinogen to fibrin
fibrin
protein that makes little fibers that aggregate like net, capturing RBCs and other platelets => clot
scab
clot forms on surface vessel that has been cut
immuno. rxns
body can differentiate between self and foreign by identifying cell-surface antigen
BP
measure of blood’s force per unit area on vessel walls
recorded as gauge pressure (pressure above atm pressure
O +
most common type of blood in US
AB-
least common type of blood in US
hemoglobin-oxygen disso.
right => less O2 bound to this -> inc. in partial pressure of CO2 => dec. in pH (inc. pressure and lactic acid build up) => inc in temp => inc. metabolic rate => signal for more O2
hydrostatic pressure
pushes fluid out of vessels (dependent on blood pressure driven by heart)
osmotic pressure
pulls fluid back into vessels (dependent on number of particles dissolved in plasma)
