Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Human physiology > cardiac output and regulation > Flashcards

cardiac output and regulation Flashcards

1
Q

what is cardiac output?

A

the amount of blood pumped by each ventricle in one minute

produce of heart rate and stroke volume

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

how do calulate cardiac output?

A

CO= HR X SV

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

what is stroke volume

A

amount of blood pumped out by a ventricle with each beat

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

what are the layers of the heart wall?

A

epicardium
myocardium
endocardium

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

what is the epicardium?

A

visceral layer of serous pericardium

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

what is pericardial fluid?

A

surronds the heart and protects it from compression

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

what is cardiac muscle?

A

fibres that wrap around the whole organ

contracts and twists to push blood out

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

why is the left side thicker?

A

higher pressure
systemic circulation here
more resistance

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

what is the coronary circulation?

A

supplies the heart with oxygen and nutrients

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

what are the two main branches of the left main coronary artery?

A

LAD

circumflex

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

what does the sympathetic nervous system do to the heart?

A

increases rate and force of contraction

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

what does the parasympathetic nervous system do to the heart?

A

slows heart rate

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

what does activation of the SAN do?

A

increases firing and thus heart rate too

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

what does the change in time lag of the cardiac cycle do?

A

allows blood to move from the atria to the ventricles

allows signal to move from the SAN to AVN

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

where are valves found in the heart?

A

2 atria ventricular valves

2 semilunar

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

what are the atria-ventricular vales?

A

mitral valves separates atrium from ventricles on each side

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

what are the semilunar valves

A

pulmonary valve goes from right ventricle to lung

aortic valve goes from left ventricle to body

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

where is the tricuspid valve found?

A

RA to RV

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

where is the pulomary valve found

A

RV to pulmonary trunk to lungs

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

where is the mitral/ bicuspid valve found?

A

LA to LV

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

where is the aortic valve found?

A

LV to aorta

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

what is the function of AV valves

A

allows blood to flow to ventricles ad prevents bacl flow during contraction

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

what are valves made of?

A

connective tissue connected to papillary muscles in endocardial wall
contraction of the muscles closes the valves

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

what are papillary muscles?

A

connected to valves and close and open them

they contract during systole and prevent valves inverting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
what is S1
the sound of the closing of AV vales at start of ventricular systole
26
what is S2
the sound of semilunar valves closing at the edn of ventricular systole
27
whats key about looking at cardaic muscle
striations collagen intercolated disks
28
how does cardiac muscle appear ?
branches of the fibres and myocytes for branches | intercolates disks are seen between sections
29
whats the function of an intercolated disk?
form the mechanical connection for contraction and force to be transmitted across the heart
30
what cells are found in the heart?
``` myocytes ECM fibroblasts muscle blood cells ```
31
what alters the distrubution of myocytes and fibroblasts?
species
32
what are the physical connections found in cardiac muscle?
intercollated disks | desmosomes
33
what do jap junctions do within cardiac muscle?
allow communication between adjacent cells | electrical, small molecules, small RNA
34
where are mitochondria found in cardiac muscle?
near the myofilament
35
define sarcomere
small region of contraction
36
thick filament
myosin
37
thin filaments
actin
38
dark bands
thick myosin mainly, some overlapping thin actin
39
A bands
ansiotrophic bands, dark | thick myosin and some ovelapping actin
40
light I bands
thin actin only
41
whats the end of a sarcomere called?
Z line connects to ECM
42
what is the M line?
middle of the sarcomere | myosin
43
what happens during contraction
I band shrinks | A and M band shrink
44
describe the steps of the sliding filament mechanism
1. tropomyosin prevents myosin head attaching to binding sites of actin 2. calcium ions released from endoplasmic reticulum causing tropomyosin to move 3. myosin can now bind to actin 4. head changes angle, moving actin along, ADP released. power stroke, conformational change 5. ATP fixes to head, myosin detaches from actin 6. ATP to ADP using ATPase makes energy for myosin head to resume normal 7. cycle repeats
45
what is actin and myosin like at rest?
proteins troponin and tropomyosin prevent myosin from interacting
46
what does calcium do to tropomyosin?
causes a conformational change allowing actin and myosin to interact
47
what is a T-Tubule?
helps transmit electrical signals into the interior of the cell act as microvili increasing surface area
48
7 steps of the cardiac cyce
``` atrial contraction isovolumetric contraction rapid ejection reduced ejection isovolumetric relaxation rapid filling reduced filling ```
49
what happens during atrial contraction
initiated by the P wave valves between atria open semilunar valves closed
50
what is isovolumetric contraction
QRS complex ventricle pressure increases with no volume change contraction without volume change no blood movement
51
what happens during rapid ejection
blood flows rapidly from ventricles to arteries AV closed semilinar open
52
what happens during isovolumetric relaxation?
valves closed venticle pressure drops no volume change but pressure drops
53
was is reduced ejection?
``` ventricles repolarise tention in ventricle reduced blood flow due to kinetic energy now volume decreased tension drops ```
54
what is isovolumetric relaxation
``` valves closed ventricle pressure drops pressure down after contraction AV valve then open no volume change but pressure down as muscle relaxes ```
55
what is the ejection fraction?
proportion ejected out but some blood left behind
56
what happens during rapid filling?
AV valves open, semilunar closed ventricular relaxation pressure lower in atria fills with blood
57
what happens during reduced filling?
chamber fills, pressure increases, amount of blood entering slows, AV open so some blood flows via gravity to ventricles semilunar closed
58
which steps of the cardiac cycle are systole?
atrial contraction isovolumetric contraction rapid ejection reduced ejection
59
which steps of the cardiac cycle are diastole?
isovolumetric relaxation rapid filling reduced filling
60
what is a diad?
The diad is a structure in the cardiac myocyte located at the sarcomere Z-line. It is composed of a single t-tubule paired with a terminal cisterna of the sarcoplasmic reticulum.
61
function of the diad?
electrical impulse travesl through the diads to the cells | causes electrochemical gates to opn
62
where does calcium come from for contraction?
first comes from outside the cell | this then triggers stores from the sarcoplasmic reticulum to be used
63
by how much does the calcium concentration increases in the cytosol ready for contraction
from 0.1uM to 10uM
64
how is calcium removed again after contraction?
calcium pump | sodium calcium exchanger
65
what is excitation-contraction coupling?
physiological process of converting an electrical stimulus to a mechanical response. It is the link (transduction) between the action potential generated in the sarcolemma and the start of a muscle contraction
66
what allows actin and myosin to bind/ interact?
the binding of calcium to trononin-C
67
what does the binding of myosin to actin result in?
ATP hydroloysis which supplies the energy for the conformational change in actin-myosin
68
how does calcium enter to cytosol?
L-type ca+2 channels
69
what is calsequestrin?
calcium-binding protein of the sarcoplasmic reticulum. The protein helps hold calcium in the sarcoplasmic reticulum after a muscle contraction, even through the concentration of Ca is higher here than in the cytosol
70
what does the sodium-calcium exchanger do?
exchanges 3 Na for each calcium uses electrogenic potential generation to work the calcium is moved out and Na in
71
why is the Na/K pump also used in muscles?
during contraction, Na comes in but you dont want too much inside so the pump helps regulate this by removing calcium, Na can get too high so it now triggers the Na/ pump to remove some Na
72
name the pacemaker electrical acitivty cells in the heart
sino-atrial node atrioventricular node bundle of his purkinje fibres
73
how do electrical activty heart cells work?
they use ATP to create a concentration gradient of either side the cell then works as a battery: then chennals are open there is a flow of ions ad a potential difference across the membrane and a flow of charge
74
what are concentrations of K like?
high within the cell low outside chemical gradient for it to diffuse out of the cell
75
what describes permeability of the cell embrane to a given ion?
conductance
76
what is conductance
modification of currentX resistance = voltage
77
when relaxed what is the potential difference of all the ions?
K higher inside Ca higher inside Na higher outside pumps maintain this
78
describe Ohms law
resistance is now conductance in this case | permeability of an ion is related to its charge
79
what determines the movement of ions?
both the concentration gradient and membrane potential | and ion pumps
80
what is the equilbrium for potassium
goes out | need negative potential
81
whats the quilibrium for sodium
high cone outside flows into cells positive potential needed to stop flow in
82
whats the equibrium for calcium
high outside flows into cells positive differene needed to repel it to move in
83
what causes action potentials in non-pacemaker cells?
depolarising currents from neighbouring cells
84
describe the generation of an acton potential
1. STIMULUS excites the membrane, Na channels open Na in, less negative 2. DEPOLARIsATION, reaches threshold, more Na influx 3. REPOLARISATION, na channes close, K open, K diffuses out, back to resting negative 4. HYPERPOLARIATION, K channels slow to close, more negative than resting 5. RESTING ion channels reset

Human physiology (21 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions