physiology Flashcards

1
Q

what is the function of the CVS (5) - what is the main theme?

A

transportation of : gas
nutrients, metabolites, hormones, heat

transportation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

how many times dose the heart beat in 70 years - what does this show

A

2.5 billion times

the heart is amazingly reliable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what shows the heart is remarkably flexible (3)

A

pump can vary output
vessels can redirect blood
vessels can store blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

why do we need a Vascular system

A

because we are not single celled and diffusion only takes part over 1mm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

the left and right ‘‘pumps’’ are said to be in what

A

series with one another

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

why in terms of the CVS is series so important

A

it means the output of both must be equal for function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are the 2 main examples of vascular beds in series

A

gut to liver

hypothalamus to anterior pituitary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are most vascular beds - what does this mean (2)

A

in parallel

all tissues get oxygenated blood

allows regional redirection of blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is special about the gut being in series with the liver (2)

A

the liver still has its own blood supply

the nutrients absorbed from the gut go directly to the liver for storage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is a problem with the evolution of the coronary blood supply

A

every time it contracts it cuts of its own blood supply

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

why is the hypothalamus in series with the anterior pituitary

A

as the hypothalamus diffuses releasing factors into the blood supply for the anterior pituitary to pickup down stream and release hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what are the 3 biggest O2 consumers

A

the abdominal organs

skeletal muscle

heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

why doses the cardiac output of the biggest O2 consumers vary

A

because it shows weather the system is effective

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

why is the kidneys CO so much greater than its O2 consumption

A

due to the kidneys job of cleaning the blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is the equation for flow

A

change in pressure /resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

why does the skin have a similar CO vs O2 consumption as the kidneys

A

as the skin is the thermoregulatory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

how does resistance changed

A

diameter changes of the blood vessels mainly arterioles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is the pressure difference

A

mean arterial pressure - central venous pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

where is the mean arterial pressure measured

A

in the arteries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

where is the central venous pressure measured

A

in the vena cava

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what do arterioles act as

A

the taps - controlling resistance to the vascular bed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what vessels does blood pass through from first to last

A

arteries, arterioles, capillaries, venules, veins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is the aorta an example of

A

elastic arteries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what are the features of elastic arteries

A

wide lumen, elastic wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
what is the function of the elastic arteries
to dampen pressure fluctuations but absorbing and smoothing out
26
what are all other arteries other than the aorta
muscular arteries
27
what is the function of muscular arteries
to be low resistance conduits and get the blood to the arterioles features, narrow lumen , thick contractile wall
28
what are arterioles examples of
resistant vessels
29
what is the function of resistant vessels
control resistance which in turn controls flow allow regional redirection of blood
30
what are the features/ from of arterioles
narrow lumen, thin wall
31
what are capillaries examples of
exchange vessels
32
what features do exchange vessels have
narrow lumen and thin walls
33
what are venules examples of
capacitance vessels
34
what are veins examples of
capacitance vessels
35
what are the features of capacitance vessels
wide lumen, distensible wall (allows the vessel to swell and expand )
36
what is the job of the capacitance vessels
like a capacitor it is to allow fractional distribution of blood (allows for some storage) between veins and heart
37
how much blood is in the venous system
2/3
38
what is the pulmonary trunk
the initial ARTERY that comes out of the right ventricle
39
what is the septum (s) in relation to CVS
the interventricular and interatrial septum's job is to separate the right and left ventricles and atrium to stop mixing/ shunting of blood.
40
what is the mitral valve
mitral = bicuspid 2 cusps stops blood being regurgitated into the left atrium from the left ventricle during contraction
41
what is the tricuspid valve
a valve with 3 cusps stops blood regurgitation from the right ventricle to atrium
42
what is fractional distribution
what the venous system dose to store a bit of blood by distending - keeping the series correct
43
what is the T-tubule
deep holes in cell
44
what is the sarcolemma
the membrane that surrounds the whole of the muscle cell
45
where is the Z line
in the middle of the T-tubule
46
what do the GAP junctions form
protein channels that let electrical current through them - the electrical connection between them - mass contraction
47
what are the thin filaments in muscle
actin
48
what is the sarcoplasmic reticulum
a big calcium cell storage
49
what are desmosomes
the stiches between the cell - leading to a p
50
how long is a cardiac action potential - compared to skeletal
250ms of cardiac vs 2ms of skeletal
51
why is a cardia action potential so long - why is this
a cardiac action potential is long so Ca2+ and Na+ can enter the cell the entry of more Ca2+ leads to a greater contraction so contraction strength can be regulated by how much Ca2+ is let in (length of action potential) - unlike skeletal muscle
52
can cardiac muscle exhibit tetanus
no
53
what is tetanus (tetanic contraction)
when skeletal muscles add multiple contractions on top of one another - i.e. holding something for long)
54
what is the name of how the gap junctions and desmosomes are arranged (alternatively)
intercalated disk
55
what do the cells that act as pacemakers have
unstable resting membrane potentials that lie a lot closer to threshold and spontaneously reach threshold
56
what dose the defibrillator do
top the hear to resent the pacemakers
57
what are the 4 stages of a non-pacemaker action potential
resting membrane potential - high resting permibalitiy ofK+ initial depolarisation - more Na+ Na+ permeability shoots up plateau - decrease in K+ and more Ca2+ (L type) repolaisation - decrease Ca2+, increase in K+
58
what happens in a pacemaker action potential
K+ gradually decreases a weird Na+ increases then a late increase in Ca2+ (T type) (initial booster to get into orbit) leads to the firing of the action potential which leads onto Ca2+ (L type) (main thruster to cause the action potential)
59
what are the drugs that modulate electrical activity in the heart
Ca2+ channel blockers - decrease force of contraction cardiac glycosides - increase force of contraction
60
what factors other than drugs have an effect on electrical activity (7)
sympathetic and parasympathetic temperature 10bpm per 1oC hyperkalaemia (high K+)- fibrillation and heart block hypokalaemia (low plasma K+) - fibrillation and hear block hypercalcemia (high plasma Ca2+) -increased HR & force of contraction hypocalcaemia (low plasma Ca2+) - decreased HR & force of contraction
61
what is the annulus fibrosis - what happens during conduction
its a ring connective tissue (WITHOUT GAP JUNCTIONS) around the tri/bicuspid valves that stops the conduction of a action potential from the atrium to the ventricle
62
how dose the wave of excitation get past the annulus fibrosus
by passing through the atrioventricular node(like a gateway) and trough the bundle of His (like a tunnel)
63
how fact dose the action potential travel in the atrium
0.5 m/sec
64
how fat does the action potential travel through the atrioventricular node - why?
0,05m/sec - to act as a delay box - time for atrium to get the last bit of blood into the ventricles
65
what are myocardial cells (myocytes)
the cardiac muscle cells
66
what are the purkinje fibres and what is there function
the fibres that make up the rapid conduction system at 5m/sec its fast so the contraction is powerful enough for the blood can be pushed and circulated
67
what happens as ventricular depolarisation begins
atrial repolarisation
68
how do electrocardiograms work (ECG)
due to the wave of depolarisation/repolarisation leading to the formation of extracellular waves
69
can a ecg record a single cell
no due to the fact that the extracellular wave is so small
70
what is the order of the hear cycle
atrium depolarisation ventricle depolarisation(atrium repolarisation) atrium repolarisation
71
what are the waves of a ECG
P, QRS, T
72
what does the P was correspond to
atria depolarisation
73
what does the QRS was correspond to
ventricular depolarisation
74
what does the T was correspond to
ventricular repolarisation
75
what is the excitiation contration coupleing system
musculoskeletal system is intricately intertwined with the nervous system, allowing muscle contraction and movement
76
why is the cardiac depolarisation so long
both Na and Ca enter Ca entry, excite controls contraction.
77
how long is cardiac muscles refectory period
250ms same length as the action potential
78
where does skeletal and some of your cardiac muscle sit normally
-90mV