cardivascular Flashcards
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
which of the following species do not possess an open circulation? molluscs arthropods mammals (some) annelids
mammals DON’T have open
> i am a mammal so i have closed
how does the heart act as a functional syncitium
it would have gap junctions to allow action potential/electrical activity to propogate
> act as a single UNIT
stroke volume can be controled extrinsically and intrinsically, name some of these methods
EXTRINSIC: circulating hormones can alter calcium availability and hence the force of contraction (excitation contraction coupling)
E. G. Thyroid hormones have many cardiovascular effects to increase cardiac output!
INTRINSIC: stretching of the muscle means more powerful contraction
> this allows cardiac output to be controls
Where do you locate the Tricuspid Valve?
A Between right atria and right ventricle
B between left atria and left ventricle
C between left ventricle and aorta
D between right ventricle and pulmonary trunk
OPTION A
yayaay
name the 2 structures that help to anchor valves
chorda tendrinae
papillary muscles
help to anchor the atrioventricular/cuspid valves
Which of the following is NOT a property of arterioles?
A Acting as a conduit for blood to capillary beds
B Acting as a pressure reservoir
C Dampening oscillations in pressure
D Less smooth muscle
E Controlling differential distribution to organs and tissues
OPTION D
arteiole has more smooth muscle to help contract and control the blood pressure!
why, if there are so many capillary beds, the overall ressitane is low?
the resitance is in PARALLEL so adding more resistors increased the TOTAL resistance of the system
> as capilaries -> vein it goes back to high resisitance as its resitance in series
normal value for blood pressure (mmHg)
120/80 contracting/relaxed
resistance of blood vessel is most sensitive to diameter of vessel heart rate length of vessel viscositiy of blood
OPTION A
vasoconstrict/smaller diameter = bigger resistance
key component of a circulatory system
pump/ propulsion force to create pressure gradient to enable bulk flow
fluid
vessels (valves to ensure unidirectioanlity)
major difference between open and closed circulation A different functions B transport different materials C structurally different D colour of blood is different
OPTION C
no venous side in open system!
What do arteries do?
Act as a pressure reservoir to drive blood forward and can control the differential distribution of blood to where its needed!!
What do veins do?
Act as blood reservoir and move low oxygen, low pressure blood
need valves to ensure undirectionality of blood
How do veins defy gravity?
Wrapped around arteries or wrapped around muscles when they contract
Skeletal muscles help prevent the pooling of blood
arteries pull and increase pressure+ SQUEEZE helping blood move past the vlaves
Where is smooth muscle present
Arterioal or venous side
Arterial side only
How can this smooth muscle tone be altered?
control of vascular tone
Neurotransmitters and hormones
Physical factors - temperature and heat
Metabolism changes/chemical - H+, ppCO2
All to alter vasoconstrict/vasodilate which helps with the differential distirbution
How does arterial pressure change with height(gravity)
Above the heart, arterial pressure decreases with height
Below the heart arterial pressure increases
Which type of intercellular junction is most likely to exist in the endothelium of aorta?
Answer:tight and anchoring junctions
The endothelium of the aorta must have tight junctions between cells to stop leakage of blood. In addition, the aortic endotheliumstands on basal lamina, which is connected with the cell via anchoring junctions.
what type of circulation do crocodilians have - double or single
double circulatory but there are non dicreet atria so some mixing of blood
what type of circulation do fish have - double or single
single circulatory system
