cardivascular Flashcards
(44 cards)
what is the fossa ovalis?
when a baby takes its first breath, the foramen ovale SEALS leaving a thin fibrous tissue remenent
(embryological remenant)
what is an open circualtion
Fluid is open to body cavities + cells, feeds directly into body cavities
> low pressure so less efficient with haemlymph
What is the 'fibrous bag structure that is around/enclosing the heart' called? pericardium perichondrium periosteum peritoneum
pericardium!! yaay
which type of endothelium does not have a complete basal lamina
fenestrated
discontinuous
continuous
Discontinous
''smooth muscle is surrounded by an internal and external elastic lamina.'' which blood vessel layer does this best decribe? tunica adventicia muscularis externa submucosa tunica media adventicia
Tunica Media!
> varies im thickeness between blood vessesl with the elastic laminas making the boundaries
> key word BLOOD vessel
In which chamber of the heart can the Foramen Ovale be seen?
the right and left atria, important for foetal circulation as oxygenated blood can bypass the lungs
> gas exchange in placenta
How would you calculate cardiac output (L/min)? what is the average human C.O?
heart rate (beats/min) x stroke volume (L/beat)
70BPM AND 70ml ~ 5L/min of cardiac output
What is the key element of an open circulatory system? blood haemolymph xylem intersitial fluid vessel elements
OPTIONB
Haemolymph bathes the internal organs and therefore directly reach every cell of the body
What do icefishes have, in order to compensate for low blood viscosity? Large heart Dense nets of blood vessels High volume of blood Large capillaries All of the above
all of the above
“In an open system, the pressue is _____ and the resistance is _____?
(flow rate = ∆P / R |∆P = driving force, R = Resistance)”
pressue is low and resistance is low
> clsoes system they are both high
what is the function of the fibrous pericardium
secretes lubricating fluid allowing free movement
protects the heart
prevents over expansion of the heart
allows for greater force of contraction
OPTION C (as does titin!)
a- serous pericardium
blood vessels have tunica media layer which has ‘‘vasa vectora’’ that are its own blood vessels. why is this necessary?
as tunica media is variable in size, sometimes the walls are too thick to recieve enough o2/nutrients from main blood suply!
what feature of coronoary arteries means they can cause heart attack?
coronary arteries supply blood to heart but there are few connections (anastomases)
so if blocked, one patch of heart spasms
what is the valve calles that is between the right atrium and the coronary sinus (large vein into the heart
atriovntriucalr valves
semilunar valve
thebesian valve
Thebesian valve
how does elastic and muscular arteries function differ?
smooths pressure and blood flow
controls distribution of blood flow to different regions
> smaller = arterioles
true of false?
tunica media is thick in veins and thin in arteriess?
FALSE
thicker in arteries than in veins as veins have wider lumens
> muscular artery t.media is domianted by smooth muscle
when would fenestrated epithelium be useful?
to move small substances into blood e.g as seen in endocrine tissues! to move hormones
> disontinuous seen in bone marrow to move large moelcules/cells
what are valves (in terms of tissue structure)
folds of the tunica intima
what is the alternative name given to capillaries with dicontinous endothelium?
sinusoid capillaries! thicker several cells thick often with dicontinous memebranes
what happens when we exercise?
> think about C.O
the heart rate increases and so does the stroke volume
>faster and more powerful breaths
how does the electrical activity of the heart relate to the contractile behavior of the heart?
Electrical activity precedes muscle/contractile activity. Electrical activity is delayed AV node before being relayed at the bundle of His and conduct down the Purkinje fibres (etc)
what does the QRS complex on an ECG represent?
A depolarisation of atria
B depolarisation of ventricles
C repolarisation of ventricles
D conduction through AV node
E ventricular depolarisation and repolarisation
OPTION B
ture of false?
all muscles have both the absolute and relatvie refractory periods
FALSE
cardiac muscle only has the absolute = full hearbeats
> if not then there would be unsteady heartbeat/firbrilations
How is this done? sodium channels remain INACTIVE
pacemaker cells in the heart unstable resting membrane. where are pacemaker cells? AVN SAN bundle of His purkinje fibres septum of ventricles bundle fibres
SAN - slow reponse cells
> allows haert to have its own INTRINSIC rhythm and action action potentials are slower and last longer
