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Cardiovascular System > Definitions > Flashcards

Definitions Flashcards

1
Q

Blood

A

a fluid that is kept in constant motion by the action of the heart

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2
Q

Plasma (3 points)

A
  • is more than half of the volume of blood
  • consist of water, dissolved substances and proteins
    considered and extracellular fluid
    has more protein than other extracellular fluids in the body
  • is the aqueous component of undisturbed blood, and contains protein clotting factors
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3
Q

Formed Elements

A

to cells or cell fragments found in the blood which helps carry out its various function

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4
Q

Red Blood Cells (RBCs)
- list their notable features (5 points)
- roles and purpose (2 points)
- come from? (2 points)

A
  • transport of dissolved gases and wastes
  • are erythrocytes

Notable features
- biconcave shape
- lack a nucleus
- lack of mitochondria and other organelles
- Sharpe: flexibility and stackability for flow
- Lack of organelles: more space for storage

  • are essential for the transport of O2 = enabled by the protein hemoglobin (Hb)
  • mature RBCs are packed full w/ the protein hemoglobin (hb) = O2 responsible for O2 transport
  • RBCs come from myeloid cells via a series of distinct stages
  • there production is stimulated by erythropoietin (EPO)
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5
Q

White Blood Cells

A

defence against pathogens against toxins

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6
Q

Platelets

A

Defence against fluid loss

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7
Q

blood testing

A

a diagnostic tool

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8
Q

Hemoglobin molecules contain:

A
  • 4 globin chains
  • 2 haem units
  • 4 Fe2 + ions
  • each Haem+Fe can carry a molecule of O2
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9
Q

Haemostasis

A

to all the physiological processes that limit or halt blood loss through damaged blood vessel
ex: clotting, coagulation

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10
Q

Serum (2 points and example)

A
  • the fluid that is left after blood clotting
  • contains H2O, solutes, a dn blood protein that is not related to clot formation
  • ex: antibodies
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11
Q

Yellow Bone Marrow

A

is mostly adipocytes

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12
Q

Red Bone Marrow

A

contains blood-forming stem cells

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13
Q

Megakaryocytes

A
  • platelets are produced by these things
  • remain in bone marrow
    shedding membrane packets containing structural proteins and enzymes (platelets)
  • platelets lack organelles & are constantly recycled by phagocytize cells (primarily in the spleen) and replaced
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14
Q

Erythropoietin (2 points and a note)

A
  • is a hormone that is secreted by the kidneys in response to hypoxia
  • stimulates RBC progenitors to divide and differentiate, enhancing RBC production
  • NOTE
    -> RBC maturation is completed after reticulocytes enter the bloodstream
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15
Q

Pulmonary circuit (2 points)

A
  • moves blood from the heart to the lungs and back
  • picking up oxygen
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16
Q

Systemic circuit

A

moves blood from the heart to all other organs in eh body and back
- delivery oxygen

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17
Q

Vasodilation

A

relaxation of smooth muscle cells

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18
Q

Vasoconstriction

A

Constriction of smooth muscle cells reduces lumen diameter

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19
Q

right side of the heart

A

receives blood from the systemic circuit and pushes it into the pulmonary circuit

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20
Q

Left side of the heart

A

receives blood from the pulmonary circuit and pushes it into the systemic circuit

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21
Q

Coronary blood vessels

A

the blood vessels of the heart
- part of the systemic circuit

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22
Q

Heart valves (3 points)

A

Function:
- control the flow of blood between chambers and into arteries
- fibrous connective tissue structures that open in response to pressure build-up in the proximal chamber
- when it closes, backflow of blood is prevented

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23
Q

Conduction system of the heart

A
  • consist of specialized cells that transmit electrical excitation from the right atrium to the rest of the heart
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24
Q

Internal conduction system

A

the heart wall coordinates the timing of contractions by a specialized internal conduction system formed from modified cardiac muscle tissue

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25
Q

Heart chamber (2 points)
- function

A

Function:
- contract and relax in a sequence of events known as the cardiac cycle
- contraction = increase pressure = blood to flow into an area w/ lower pressure

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26
Q

Systole

A

refers to the contraction of the heart chamber

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27
Q

diastole

A

refers to the relaxation of a heart chamber

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28
Q

Myofibrils

A
  • the individual cardiac muscle cell (cardiomyocyte) is a tubular structure composed of chains of myofibrils, which are rod-like units within the cell.
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29
Q

Cardiac Myocytes

A
  • are striated muscle
  • share key structural features w/ skeletal myofibres
  • have organelles that contain myosin and actin filaments organized in repeating sarcomeric units
  • they form a functional syncytium, linked by intercalated discs and gap junctions
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30
Q

Gap junction

A

allows ions (and thus membrane potential signals) to flow between cells

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31
Q

Intercalates discs (2 points)

A
  • physically link the plasma membrane of two cells
  • these linkages mean that myocytes are both physically and electrochemically connected and can act like a large, single-unit
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32
Q

Why are Cardiac APs prolonged?

A

are prolonged bc/ they involve the opening of L-type voltage-gated calcium channels

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33
Q

L-Type channels

A

are the long lengths of the opening and also for a long time it takes them to get open

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34
Q

Cardiac Action Potential (AP) (5 points)
-during cardiac AP, cardiac myocytes cannot…
- a single AP generates a single contraciton in …
- but in ________, a second AP ______…
- the conduction pathway is formed from….
- these cells lack…. but are ….

A
  • during the cardiac AP (its refractory periods), cardiac myocytes cannot produce tetanus
  • A single AP generates a single contraction (twitch) in both skeletal myofibres and cardiac myocytes
  • but in cardiac myocytes, a second AP CANNOT be generated until the twitch is nearly over
  • the condition pathways are formed from highly modified cardiac myocytes
  • these cells lack myofibrils but are highly excitable and connected by gap junctions
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35
Q

Sinoatrial (SA) node
- General ( points)
- Electrical activity of SA node cells = 2 parts (2 points) (hint: action potential and peacemaker potential)

A
  • and SA node cell is a pacemaker cell
  • its Vm is NEVER at rest
    -> It generates its own (intrinsic) rhythm of regular repolarization and depolarization
  • membrane potential of SA node cells involves a fast calcium-based action potential and a peacemaker potential

Electrical activity of SA node cells
1. Actions potential: depolarization generated by T-type VGCCs
2. Peacemaker Potential: a slow depolarization that automatically restarts after every repolarization

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36
Q

Peacemaker potential (2 points)

A
  • comes from ‘funny channel’, which is opened by hyperpolarization
    during the peacemaker potential a
    funny current’ flows across the cardiac myocyte plasma membrane
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37
Q

Voltage-dependent gating (2 points)

A
  • comes form the ‘funny channel’ (aks Hyperpolarization-activated Cyclic Nucleotide-gated’ -> HCN channel)
  • the ‘funny channel’ is a voltage - gated cation channel that only opens when the membrane is hyper-polarized (allowing Na+ to enter the cell)
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38
Q

AV node (4 points)

A
  • causes 100ms to delay the spread of depolarization
  • electrical activity cannot spread directly from atrial wall myocytes to ventricle wall myocytes
  • has few gap junctions, which slows down AP transmission between its cells
  • has peacemaker properties but its intrinsic system is much slower than the SA node
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39
Q

Rhythmic electrical activity (1 point)
- electrocardiogram (ECG) (3 points)
- ECG P wave(2 points)

A
  • is detected by an electrocardiogram (ECG)

electrocardiogram (ECG):
- detected by electrodes on the skin reveals a characteristic pattern of deletions related to the electrical events in heart chamber walls

ECG P wave
- relates to atrial depolarization
- it is due to the depolarization from AP occurring in cardiac myocytes within the atrial wall

Notes:
- the exact shape depends on the location of the electrodes being recorded

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40
Q

QRS complex and T wave
(4 points)

A
  • both relate to ventricular depolarization and repolarization

QRS complex
- is large bc/ there are more myocytes in the ventricular walls than in the atrial walls
- they depolarize nearly at the same time

T Wave
- is due to repolarization of the ventricular myocytes

Note: do not need to explain why the QRS complex has 3 opponents

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41
Q

Arrhythmias (7 points total)
- Sinus Arrhythmias
- Premature atrial contraction
- Tachycardia
- Bradycardia

A
  • patterns of cardiac electrical activity
  • can be a sign of disease (depending on the case)

Sinus Arrhythmias
- intervals between heart beats varies 5% during respiratory cycle and up to 30% during deep respiration

Premature atrial contraction
- occasionally shortened interval between 1 contraction and the next

Tachycardia
- heart rate> 100bpm (ex: babies, exercise, unusual for adults at rest)

Bradycardia
- heart rate < 60 bpm (common fr athletes at rest but should rise w/ exercise)

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42
Q

Cardiac Output
- what are the units?

A
  • the volume of blood (mL) moved through the heart into the systemic circuit a given time (min)
  • is the volume of blood pumped into the aorta by the left ventricle each min

CO (Cardiac output) =mL/min

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43
Q

Heart rate

A

the number of cardiac cycles (beats) per min (bpm)

44
Q

Stroke volume

A

the volume of blood (mL) ejected into the artery during each cardiac cycle (mL/beat)

45
Q

Ventricular Systole

A

in involved a brief period of isovolumetric contraction and then a period of ventricular ejection

46
Q

Isovolumetric contraction

A

occurs when pressure is rising but both valves area still closed

47
Q

Ventricular ejection

A

occurs as long as the semilunar valves are open, allowing the stroke volume to be squeezed into the artery

48
Q

Isovolumetric relaxation

A

occurs when pressure is decreasing w/ no change in volume (both valves closes)

49
Q

End Systolic Volume (ESV)

A
  • as ventricular diastole begins, the semilunar valves close; remaining blood in the ventricle
  • a significant fraction of the EDV remains in the ventricle at the end of the cycle
50
Q

Venous Return (VR)

A
  • the volume of blood that is delivered to the right atrium during the cardiac cycle
  • is affected by CO and by constrictions of arteries or compression of veins
51
Q

Ventricular filling time

A
  • the duration of ventricular diastole, which determines the time the AV valves are open
  • as HR increases = decrease filling time
52
Q

Contractility

A

refers to the amount of force produced by contraction at a given EDV and is altered by sympathetic and hormone activity

53
Q

Maximum Heart Rate
- range
- rule of thumb equation
- what can’t you do?

A
  • +/- 15-20 bpm
  • HRmax = 220 - your age
  • can’t train yourself to have a higher HRmax
54
Q

Pressure Gradient

A

will produce a force that moves fluid in the direction of lower pressure

55
Q

Poiseuille’s Law
- and equation

A

describes these relationships for laminar flow in a cylindrical tube

Volume Flowrate (mL/s) = F = (P1-P2)/ R

R = resistance
P = pressure gradient (transluminal)

56
Q

Viscosity

A

is the measure of resistance due to interactions amount the molecules in the moving fluid

57
Q

Laminar flow

A

the liquid is moving in one direction in smooth layers

58
Q

Turbulent flow
- when can it occur

A

these layers are disrupted, and the movement is not all unidirectional (overall flow is reduced for a given pressure gradient)

  • it can occur due to shifts or changes in the geometry of the vessel wall:
    -> branch points
    -> tight curves
    -> irregular surfaces
59
Q
A
60
Q
A
61
Q

Pulse Pressure

A

difference between systolic pressure and diastolic pressure

62
Q

Mean arterial pressure (MAP)

A

diastolic pressure plus 1/3 pulse pressure

63
Q

Elastic arteries (3 points)

A
  • helps buffer the pulse pressure, reducing the variability in blow flow and pressure in capillaries
  • they stretch when blood is forced into them w/ high pressure, temporarily reducing the blood flow rate
  • when pressure drops, the wall recoils, providing extra force that enhances low-flow
64
Q

Capillary Beds

A

connect between an arteriole and venule

65
Q

Arteiroles and Anastomoses

A
  • controls the total flow of blood through the capillary bed
  • contraction of smooth muscle arterioles can reduce blood supply to the entire capillary bed
66
Q

Arteriovenous anastomoses

A

can dilate, diverting blood away form the higher resistance in the rest of the capillary beds

67
Q

Precapillary sphincter

A

go through periods of contraction and dilation causing blood to flow to be pulsative in each capillary

68
Q

Capillary (4 points)

A
  • walls consisting of a layer of endothelial cells and a basement membrane
  • transport of substance can occur across the endothelial membrane according to their chem and/or availability of carrier proteins
  • some fluid can flow between endothelial cells (paracellular transport) in a typical continuous capillary via tight junctions
  • the blood flow is really slow through this
69
Q

Fenestrated capillaries (2 p)

A
  • the pores allow for a faster exchange of water and small solutes
  • are found in areas involved in absorption (intestine) or filtration (kidneys) and many (neuro)endocrine organs (ex: hypothalamus, pituitary, thyroid)
70
Q

Sinusoidal Capillaries

A
  • have a discontinuous epithelium, allowing for movement of very large molecule
71
Q

Diffusion

A
  • does not require ATP
  • allows h20, ions and small organic molecules to diffuse through
72
Q

Hydrostatic pressure

A

refers to the force exerted on the vessel wall by the fluid inside

73
Q

Osmotic pressure

A

force that is pushing water to flow by osmosis and can be measured by the hydrostatic force it takes to stop the osmotic flow

74
Q

Net filtration Pressure
- what is the formula

A

capillaries depend on the balance between the 2 different kinds of pressure

NFP = CHP - BCOP

75
Q

Capillary hydrostatic Pressure (CHP)

A

pressure of the blood contents inside the capillary on the capillary walls

76
Q

Blood colloid osmotic pressure (BCOP)

A

pressure driving water form ISF due to the presence of large suspended molecules (especially proteins) in plasma that cannot cross

77
Q

Net filtration pressure (NFP)

A

Pressure gradient available to produce filtration

78
Q

Rate of diffusion

A
  • depends on the chemical properties of the substance
  • very large molecules, are unable to cross cell membranes (except by exocytosis)
79
Q

Recall of fluid (5 p)

A
  • change in CHP or BCOP can alter the NFP, leading to ‘recall of fluid’
  • changes in CHP or BCOP can change relative rates of filtration and reabsorption and reabsorption in capillaries
  • reabsorption > filtration
    -> due to decreased blood volume and increase plasma osmolarity (dehydration)
80
Q

Oedema (5 p)

A
  • change in CHP or BCOP could alternatively lead to oedema if the NFP changes are in the opposite direction
  • changes in CHP or BCOP can change relative rates of filtration and reabsorption in capillaries
  • filtration > reabsorption
    -> Due to decreased plasma proteins, increased blood volume, decreased venous return
81
Q

Blood pressure
- what is it affected by?
- water balloon analogy?

A
  • is affected by total blood volume and the total resistance across all blood vessels

Water balloon analogy: pressure inside the balloon is determined by 2 factors
-> Volume
-> Resistance

82
Q

Vasomotor fibres

A
  • The autonomic nervous system regulates vasoconstriction through (sympathetic0 vasomotor fibres
83
Q

Sympathetic postganglionic axon

A
  • of the ANS makes synapses on vascular smooth muscle
    these axons are known as ‘vasomotor fibres’
  • APs in vasomotor fibres lead to an enhanced contraction in smooth muscle; increased ‘Vasomotor tone’
  • the parasympathetic division does not synapse on blood vessels (there is an exception)
84
Q

Lymphatic vessels

A
  • reabsorption of filter fluid is not complete under normal physiological conditions - the excess is returned through the lymphatic vessels
85
Q

Baroreceptor (6p)
- location
- function
- where to they send … to

A
  • sensed by baroreceptors, and their info is relayed to the hindbrain
  • they are mechanosensory neurons that monitor mean arterial blood pressures
  • they are found within in carotid sinus and aortic arch
  • these neurons send their axons (CN IX and CNX) to the medulla oblongata
  • information is integrated within cardiovascular monitoring centres in the brainstem
  • they send axons (via CN IX and CN X) to cardiovascular centres within the medulla oblongata
86
Q

Arterial chemoreceptors (2 p)

A
  • drives homeostatic reflexes that alter blood flow throughout the circulatory system
  • chemoreceptive reflexes alter blood flow (and respiratory rate) to regulate blood pH, Po2, and Pco2
87
Q

Blood gas composition

A

is sensed by chemoreceptors in the brain. carotid bodies and aortic bodies

88
Q

Chemoreceptors (2 p)

A
  • info in integrated within cardiovascular monitoring centres in the brainstem
  • peripheral neurons send axons (via CN IX and CH X) to 2 cardiovascular centres (and a respiratory centre) within the medial oblongata
89
Q

Blood gas composition (3p)

A
  • the effectors for short-term alterations in blood gas compositions are the heart and the blood vessel walls
  • the cardiac centres int eh medulla oblongata drive changes in cardiac output by altering activity in ANS inputs to the SA node of the heart and the myocardium
  • the vasomotor centre drives changes to blood vessel diameter (in both arteries and veins) by altering activity in sympathetic vasomotor fibres
90
Q

Angiotensin II

A
  • stimulates the release of aldosterone and also enhances the release of ADH/ vasopressin
  • acts as a regulatory hormone, enhancing the release of 2 effector hormones
91
Q

Aldosterone

A
  • is synthesized in the most superficial; a layer of the adrenal cortex
  • it influences Na+ rention by the kidneys which indirectly contributes to h20 retention
92
Q

Natriuretic peptides (4p)

A
  • act on blood vessels and kidneys and inhibit the release of other hormones
  • it stimulates the kidney to increase the excretion of NA+, = water loss
  • has short-term effects on BP; they produce vasodilation in most blood vessels
  • regulate hormones that inhibit the release of renin (thus aldosterone), ADH, and epinephrine
93
Q

Medium to long-term (3p)

A

lost of blood volume and blood content will be replaced

Medium-term: reduction in BP leads to a decrease in CHP, which leads to ‘recall of fluid’ from the ISF

Long-term: increase in ATII, ADH, aldosterone -> leads to increased fluid intake and increased fluid retention. EPO restores RBCs

94
Q

Hypovolemic shock

A

occurs after major blood loss

95
Q

Circulatory shock symptoms

A
  • rapid, weak pulse
  • cold
  • pale
  • thirst
  • sweating
  • altered consciousness
  • nausea/ vomiting
96
Q

Intrinsic regulation

A

regulation by factoring in occurring within the local environment of that vessel. Can be direct or indirect

97
Q

Extrinsic regulation

A

regulation by mechanism involving integrative organ system (outside the local environment)

98
Q

Vasodilation
- directly and indirectly
- stimuli (4 total)

A
  • can occur directly through changes in gases, ions or metabolites in the surrounding tissue
  • or indirectly through paracrine signalling pathways

Stimuli
- Decrease O2
- increase CO2
- Increase H+
- Increase K+

99
Q

Paracrine factor

A

are chemical messengers that remain within their local environment

100
Q

Vasoactive paracrine factors

A

can be generated in surrounding tissues or by endothelial cells

101
Q

Nitric oxide (NO)

A

soluble gas is a particularly important paracrine factor that causes smooth muscle relaxation by reducing Ca2+ entry into smooth muscle

102
Q

Vasoconstriction
- autogeneration can occur via..
-> myotonic
-> endothelins

A

Myogenic: stretching vascular smooth muscle triggers an increase in its contraction, returning vessel diameter to the original value

Endothelins: are paracrine factors which are constantly secreted at low levels, helping to maintain a baseline state of slight vasoconstriction

103
Q

Vasomotor fibres

A
  • the autonomic nervous system extrinsically regulates vasoconstriction through vasomotor fibres
  • APs in sympathetic vasomotor fibres lead to enhanced contraction in smooth muscle (increased vasomotor tone)
104
Q

Adrenergic signalling

A

sympathetic postganglionic axon terminal mostly releases NE, with small amounts of E

105
Q

Endocrine adrenergic signalling

A

Adrenal medulla mostly released E, with small amount of NE

106
Q
A

Cardiovascular System (2 decks)

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