Definitions Flashcards
(106 cards)
1
Q
Blood
A
a fluid that is kept in constant motion by the action of the heart
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
3
Q
Formed Elements
A
to cells or cell fragments found in the blood which helps carry out its various function
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)
5
Q
White Blood Cells
A
defence against pathogens against toxins
6
Q
Platelets
A
Defence against fluid loss
7
Q
blood testing
A
a diagnostic tool
8
Q
Hemoglobin molecules contain:
A
- 4 globin chains
- 2 haem units
- 4 Fe2 + ions
- each Haem+Fe can carry a molecule of O2
9
Q
Haemostasis
A
to all the physiological processes that limit or halt blood loss through damaged blood vessel
ex: clotting, coagulation
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
11
Q
Yellow Bone Marrow
A
is mostly adipocytes
12
Q
Red Bone Marrow
A
contains blood-forming stem cells
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
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
15
Q
Pulmonary circuit (2 points)
A
- moves blood from the heart to the lungs and back
- picking up oxygen
16
Q
Systemic circuit
A
moves blood from the heart to all other organs in eh body and back
- delivery oxygen
17
Q
Vasodilation
A
relaxation of smooth muscle cells
18
Q
Vasoconstriction
A
Constriction of smooth muscle cells reduces lumen diameter
19
Q
right side of the heart
A
receives blood from the systemic circuit and pushes it into the pulmonary circuit
20
Q
Left side of the heart
A
receives blood from the pulmonary circuit and pushes it into the systemic circuit
21
Q
Coronary blood vessels
A
the blood vessels of the heart
- part of the systemic circuit
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
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
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
25
Heart chamber (2 points)
- function
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
26
Systole
refers to the contraction of the heart chamber
27
diastole
refers to the relaxation of a heart chamber
28
Myofibrils
- the individual cardiac muscle cell (cardiomyocyte) is a tubular structure composed of chains of myofibrils, which are rod-like units within the cell.
29
Cardiac Myocytes
- 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
30
Gap junction
allows ions (and thus membrane potential signals) to flow between cells
31
Intercalates discs (2 points)
- 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
32
Why are Cardiac APs prolonged?
are prolonged bc/ they involve the opening of L-type voltage-gated calcium channels
33
L-Type channels
are the long lengths of the opening and also for a long time it takes them to get open
34
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 ....
- 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
35
Sinoatrial (SA) node
- General ( points)
- Electrical activity of SA node cells = 2 parts (2 points) (hint: action potential and peacemaker potential)
- 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
36
Peacemaker potential (2 points)
- comes from 'funny channel', which is opened by hyperpolarization
during the peacemaker potential a
funny current' flows across the cardiac myocyte plasma membrane
37
Voltage-dependent gating (2 points)
- 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)
38
AV node (4 points)
- 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
39
Rhythmic electrical activity (1 point)
- electrocardiogram (ECG) (3 points)
- ECG P wave(2 points)
- 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
40
QRS complex and T wave
(4 points)
- 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
41
Arrhythmias (7 points total)
- Sinus Arrhythmias
- Premature atrial contraction
- Tachycardia
- Bradycardia
- 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)
42
Cardiac Output
- what are the units?
- 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
43
Heart rate
the number of cardiac cycles (beats) per min (bpm)
44
Stroke volume
the volume of blood (mL) ejected into the artery during each cardiac cycle (mL/beat)
45
Ventricular Systole
in involved a brief period of isovolumetric contraction and then a period of ventricular ejection
46
Isovolumetric contraction
occurs when pressure is rising but both valves area still closed
47
Ventricular ejection
occurs as long as the semilunar valves are open, allowing the stroke volume to be squeezed into the artery
48
Isovolumetric relaxation
occurs when pressure is decreasing w/ no change in volume (both valves closes)
49
End Systolic Volume (ESV)
- 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
Venous Return (VR)
- 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
Ventricular filling time
- the duration of ventricular diastole, which determines the time the AV valves are open
- as HR increases = decrease filling time
52
Contractility
refers to the amount of force produced by contraction at a given EDV and is altered by sympathetic and hormone activity
53
Maximum Heart Rate
- range
- rule of thumb equation
- what can't you do?
- +/- 15-20 bpm
- HRmax = 220 - your age
- can't train yourself to have a higher HRmax
54
Pressure Gradient
will produce a force that moves fluid in the direction of lower pressure
55
Poiseuille's Law
- and equation
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
Viscosity
is the measure of resistance due to interactions amount the molecules in the moving fluid
57
Laminar flow
the liquid is moving in one direction in smooth layers
58
Turbulent flow
- when can it occur
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
60
61
Pulse Pressure
difference between systolic pressure and diastolic pressure
62
Mean arterial pressure (MAP)
diastolic pressure plus 1/3 pulse pressure
63
Elastic arteries (3 points)
- 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
Capillary Beds
connect between an arteriole and venule
65
Arteiroles and Anastomoses
- 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
Arteriovenous anastomoses
can dilate, diverting blood away form the higher resistance in the rest of the capillary beds
67
Precapillary sphincter
go through periods of contraction and dilation causing blood to flow to be pulsative in each capillary
68
Capillary (4 points)
- 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
Fenestrated capillaries (2 p)
- 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
Sinusoidal Capillaries
- have a discontinuous epithelium, allowing for movement of very large molecule
71
Diffusion
- does not require ATP
- allows h20, ions and small organic molecules to diffuse through
72
Hydrostatic pressure
refers to the force exerted on the vessel wall by the fluid inside
73
Osmotic pressure
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
Net filtration Pressure
- what is the formula
capillaries depend on the balance between the 2 different kinds of pressure
NFP = CHP - BCOP
75
Capillary hydrostatic Pressure (CHP)
pressure of the blood contents inside the capillary on the capillary walls
76
Blood colloid osmotic pressure (BCOP)
pressure driving water form ISF due to the presence of large suspended molecules (especially proteins) in plasma that cannot cross
77
Net filtration pressure (NFP)
Pressure gradient available to produce filtration
78
Rate of diffusion
- depends on the chemical properties of the substance
- very large molecules, are unable to cross cell membranes (except by exocytosis)
79
Recall of fluid (5 p)
- 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
Oedema (5 p)
- 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
Blood pressure
- what is it affected by?
- water balloon analogy?
- 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
Vasomotor fibres
- The autonomic nervous system regulates vasoconstriction through (sympathetic0 vasomotor fibres
83
Sympathetic postganglionic axon
- 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
Lymphatic vessels
- reabsorption of filter fluid is not complete under normal physiological conditions - the excess is returned through the lymphatic vessels
85
Baroreceptor (6p)
- location
- function
- where to they send ... to
- 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
Arterial chemoreceptors (2 p)
- 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
Blood gas composition
is sensed by chemoreceptors in the brain. carotid bodies and aortic bodies
88
Chemoreceptors (2 p)
- 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
Blood gas composition (3p)
- 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
Angiotensin II
- 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
Aldosterone
- 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
Natriuretic peptides (4p)
- 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
Medium to long-term (3p)
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
Hypovolemic shock
occurs after major blood loss
95
Circulatory shock symptoms
- rapid, weak pulse
- cold
- pale
- thirst
- sweating
- altered consciousness
- nausea/ vomiting
96
Intrinsic regulation
regulation by factoring in occurring within the local environment of that vessel. Can be direct or indirect
97
Extrinsic regulation
regulation by mechanism involving integrative organ system (outside the local environment)
98
Vasodilation
- directly and indirectly
- stimuli (4 total)
- 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
Paracrine factor
are chemical messengers that remain within their local environment
100
Vasoactive paracrine factors
can be generated in surrounding tissues or by endothelial cells
101
Nitric oxide (NO)
soluble gas is a particularly important paracrine factor that causes smooth muscle relaxation by reducing Ca2+ entry into smooth muscle
102
Vasoconstriction
- autogeneration can occur via..
-> myotonic
-> endothelins
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
Vasomotor fibres
- 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
Adrenergic signalling
sympathetic postganglionic axon terminal mostly releases NE, with small amounts of E
105
Endocrine adrenergic signalling
Adrenal medulla mostly released E, with small amount of NE
106
