Week 1 Flashcards
1
Q
What two types of dyes are there and what components of the cell do they interact with? Specify the color of these types of dyes and specify the specific organelles.
A
- Basophilic (anionic components) react with basic dyes (+)
- DNA, RNA, Glycoaminoglycans
- Blue-purple dyes
- Acidophilic (cationic components) react with acidic dyes (-)
- Mitochondria, collagen, secretory granules
- Red-yellow-orange dyes
2
Q
What type of stain is this? What organelles does it stain and what colors? What does it not stain?
A
Stain: Hemotoxylin and Eosin (H&E)
Description
- Stains nuclei blue and stains cytoplasm red
- Does not stain fibers*
3
Q
What stain is this? What structures does it stain and what color?
A
Stain: Periodic Acid Shift Method (PAS)
Description: Stain carbohydrates purple (i.e. basement membranes and reticular fibers)
4
Q
What stain is this and what is this stain a mixture of? What does the dye emphasize? What kind of colors are involved?
A
Stain: Trichrome stains
Description: Mixture of three dyes emphasizes connective tissue and fibers (i.e. collagen) *Bright colors involved
5
Q
What stain is this? What two structures does it stain and what colors?
A
Stain: Van Gieson
Description: Collagen (pink-red), muscle (yellow)
6
Q
What stain is this? What does it stain and what color?
A
Stain: Verheoff-Van Gieson
Description:
- Elastic fibers – brown-black
- Collagen fibers – pinkish-red
- Muscle - yellow
7
Q
What are the layers of the heart from outside to inside?
A
Epicardium, myocardium, enocardium
8
Q
What layer of the heart is this? What is one of the layers in this part and what cells make up this layer? What kind of tissue is involved here and whta kind of cells/vessels?
A
Epicardium
- Mesothelium: simple squamous cells form lining of visceral pericardium
- Loose connective tissue
- Blood vessels, nerves, adipocytes
9
Q
What layer of the heart is this? What makes up most of this layer?
What is a pathological condition that can occur killing cells in this layer? What is the result?
This layer is thicker where?
A
Myocardium
- Cardiac muscle (layered cardiomyocytes)
- Striated, centrally located nuclei, intercalated discs, branching
- Heart attack causing loss of O2 due to ischemia > 20 minutes → necrosis of cardiomyocytes → loss of intracellular striations
- Thicker in the walls of the ventricles
*asterisk denotes the chamber
10
Q
What kind of cells are these and what layer of the heart are they found in?
A
Cardiomyocytes in the myocardium
11
Q
What layer of the heart is this? What are some unique characteristics? What are the three layers of this layer (deep to superficial)?
A
Endocardium
- Lots of nuclei
- Deep to superficial:
- Endothelium: subendothelial connective tissue
- Myoelastic layer: smooth muscle and connective tissue
- Subendocardial layer: branches of conducting system
- Purkinje fibers: pale staining; larger than the cardiac muscle; larger, rounder nuclei
12
Q
What are the layers of the vascular wall (inner to outer) and describe each layer (what fibers and what kind of tissue/muscle)?
A
inner to outer
- Tunica Intima – endothelium, basal lamina, and a subendothelial layer
- Tunica Media: circularly arranged layers of smooth muscle with elastic fibers
- Tunica Adventitia: loose connective tissue, collagen, and elastic fibers
13
Q
What are the three tyes of arteries?
A
- Elastic arteries
- Muscular arteries
- Arterioles
14
Q
What type of arteries are these? Are they the biggest, medium, or smallest arteries? What is a unique characteristic?
A
Elastic Arteries
- Largest arteries (i.e. aorta, common carotid)
- Thick tunica media (high density of elastic fibers)
15
Q
What kind of arteries is this? Small, medium, or large arteries? What are some unique characteristics?
A
Muscular Arteries
- Medium arteries
- High density of elastic fibers with increasing mass of smooth muscle tissue
- “rippled” looking endothelium
16
Q
What kind of arteries is this? Small, medium, or large? What are some unique characteristics?
A
Arterioles
- Smallest arteries
- Elastic laminae absent
- Thin tunica adventitia
17
Q
What are the three kind of capillaries?
A
- Continuous capillary
- Fenestrated capillary
- Discontinuous capillary
18
Q
Describe continuous capillary in terms of the endothelium. What is the basal lamina like?
A
- Uninterrupted endothelium – tight junction – to restrict movement of large molecules
- Continuous basal lamina
19
Q
Describe fenestrated capillary in terms of the endothelium. What is the basal lamina like?
A
- Endothelium with small holes
- Continuous basal lamina
20
Q
Describe discontinuous capillary (sinusoids) in terms of the endothelium. What is the basal lamina like?
A
- Large perforation in endothelial cells that exchange macromolecules
- Discontinuous basal lamina
21
Q
What are the three types of veins and what are the characteristics of veins on histology?
A
Very compressible and usually not perfect circles
- Venules
- Small and medium veins
- Large veins
22
Q
What is a unique characteristic of venules?
A
No tunica intima
23
Q
What are some unique characteristics of small and medium veins?
A
- Has all tunica layers
- Some medium veins possess valves
24
Q
What are some unique characteristics of large veins?
A
- Some large veins have valves
- Thick tunica adventitia
25
What are the two types of lymphatic structures?
* Lymphatic Capillaries
* Lymphatic Vessels
26
What is a lymphatic capillary? What is the basal lamina like?
Single layer of endothelium, incomplete basal lamina
27
What are some distinctive factors for lymphatic vessels?
* No distinct separation among tunics
* Lots of valves – more than veins
28
What is the vasa vasorium?
Vasa vasorium – internal blood supply for large veins (picture shows thoracic duct)
29
Be familiar with the following.
30
What occurs right before the Q wave on the Wigger's Diagram? Describe the full process and what the end result is.
* Rapid Inflow: passive flow into the atria and ventricles, due to the AV valves being opened (atrial pressure = ventricular pressure) → increase in ventricular volume
31
What ocurrs during the P-wave in the Wigger's diagram? Explain the whole process.
* P-wave: atrial depolarization → contraction of atria → slight increase in atrial pressure → pushes blood from left atrium to left ventricle → peak of ventricular volume is reached
32
What occurs in the QRS? Explain the whole process.
* QRS: ventricular depolarization → ventricular contraction → LARGE increase in ventricular pressure → AV valve closes (ventricular pressure \> atrial pressure) → isovolumic contraction (pressure builds up) → opening of aortic valve (ventricular pressure \> aortic pressure) → ventricular volume decreases as blood goes into systemic circulation
33
What occurs in the T-wave? Explain the whole process.
* T-wave: repolarization of the ventricles → isovolumic relaxation of the ventricles (b/c both valves are still closed) → pressure in the ventricles decreases → AV valve opens (atrial pressure = ventricular pressure) → ventricular volume starts going up
34
Draw the Wigger's Diagram.
35
Compare some differences between the left and right side of the heart. There are a total of 4.
* Location of SA node is in the “high” right atrium → right atrial contraction starts before the left atrium
* Ventricular contraction starts earlier on the left side
* Mitral valve closes slightly before tricuspid
* Right ventricle has a shorter period of isovolumetric contraction
* Pulmonary valve opens before aortic valve
* Left ventricular ejection ends first
* Aortic pressure is higher so aortic valve is shut earlier (A2 should precede P2)
36
What is the function of the valves? What are the two heart sounds and when do they occur?
* Valves prevent backflow
* Two Heart Sounds
* Lub – S1: when mitral valve and tricuspid valves close
* Dub – S2: when aortic and pulmonary valves close
37
What are the main local mechanisms controlling blood flow? How do they occur in terms of active "hyperemia" or reactive "hyperemia"?
* Local
* Local metabolic influences: CO2, H+, adenosine
* Active “hyperemia” (high flow): proactive response to increase in metabolic activity → increase blood flow
* Reactive “hyperemia”: occlusion of blood → accumulation of metabolites or myogenic response → sudden and transient increase in blood flow when restriction is released
* Myogenic response: smooth muscle inherently tries to maintain length
* Smooth muscle suddenly exposed to distending pressure → increased passive stretch of wall and dilates temporarily increasing flow → active vasoconstriction back to normal length
* Can also be reactive hyperemia
38
Define flow autoregulation. What is it mediated by?
* Flow autoregulation: maintenance of constant flow despite variations in BP in organs
* Initial: increased pressure causes increased flow
* Autoregulation: vessels constrict to increase resistance and decrease flow
* Mediated by myogenic response or changes in local metabolites
39
What are some extrinsic mechanisms controlling blood flow? Think neural and hormonal
* Neural/Hormonal
* Circulating catecholamines (NE and EPI)
* Alpha1
* Beta1
* Beta2
* Vasopressin (anti-diuretic hormone)
* Angiotensin II
40
What is the mechanism of all of the below:
* Alpha1
* Beta1
* Beta2
* Vasopressin (anti-diuretic hormone)
* Angiotensin II
* Alpha1: vascular receptor leading to constriction
* Beta1: heart receptor leading to contractility
* Beta2: smooth muscle receptor leading to vasodilation
* Vasopressin (anti-diuretic hormone)
* Vasoconstrictor
* Angiotensin II
* Potent vasoconstrictor
41
How does the vascular control of coronary blood flow occur? How are the left coronary arteries and right coronary arteries affected?
* Coronary blood flow is controlled by metabolic factors produced by cardiomyocytes
* The left coronary artery (LCA) is collapsed during the systole because the pressure in the left ventricle is higher than the pressure in the coronary (causing compression of the LCA)
* The right coronary artery is unaffected by systolic pressure because the pressure in the right ventricle is lower than the pressure in the coronary
* Sympathetic nervous system increases contractility of heart, which produces metabolic vasodilators in the heart (generally causes vasoconstriction elsewhere) to supply the needs of the coronary arteries
42
How do the arteries react in the vascular control of skeletal muscle blood flow?
* During muscle use, sympathetic nervous system causes vasoconstriction of the blood vessels supplying the muscle.
* However, during conditions like exercise, metabolic demand will override any sympathetic output and cause vasodilation (i.e. cycling: arms will not release a lot of metabolites because they do not require as much O2, but your legs will release a lot of metabolites due to O2)
43
What would occur to the arteries if someone with hypertension tries to bench press an unreasonable amount of weight?
If someone with HTN bench presses weight, the blood supply in the arm during contraction goes to zero because of muscles constricting the arteries. In response, local cells release metabolite activators causing local vasodilation. This is bad because the sympathetic nervous system causes vasoconstriction elsewhere in the body
44
What is the role of veins in the vascular control of blood flow to skeletal muscles?
* Veins
* Deep veins have valves to prevent backflow of blood
* Active muscle constriction pushes venous blood back to heart
* Muscle relaxation allows for capillary perfusion (due to low venous pressure)
45
What equation is used to calculate the transcapillary solute diffusion (concentration)?
* Fick’s First Law of Diffusion
* change in [substance] = concentration difference
* A = surface area
* change in L = thickness of capillary
* D = permeability coefficient of substance (higher means increased diffusion)
46
What equation is used to calculate the transcapillar fluid movement?
* Starling Equation
* Jv = Kf [(Pc-Pi)- rho(Pic-Pii)]
* Jv = net fluid flux
* Pc/i = capillary/interstitial hydrostatic pressure
* ![]()Pic/i = capillary/interstitial osmotic/oncotic pressure
* Kf = filtration coefficient
* ![]()Rho varies between 0-1 (close to 1 in renal glomeruli and close to 0 in hepatic sinusoids)
47
Explain this picture.
* Hydrostatic pressure coming from arterioles is higher than the hydrostatic pressure in the interstitial fluid. Therefore, fluid travels into the interstitial fluid from the capillary on the arteriole side.
* As fluid travels across, the hydrostatic pressure decreases because of the loss of the fluid to the interstitial. Consequently, the osmotic pressure increases (due to the increased concentration of proteins) causing the fluid to be absorbed into the capillary on the venous side.
48
List the 4 causes of edema overall?
* Increased filtration pressure
* Decreased osmotic pressure gradient across capillary
* Increased capillary permeability
* Inadequate lymph flow
49
How can increased filtration pressure occur, leading to edema? 3 ways.
* Arteriolar dilation: increase in flow, therefore increase in hydrostatic pressure in the capillary
* Venular dilation: decrease in pressure difference across the capillary, therefore hydrostatic pressure in the capillary stays high
* Increased venous pressure (heart failure, incompetent valves, venous obstruction)
50
Provide an example of decreased osmotic pressure gradient across a capillary.
* If albumin falls, osmotic pressure decreases, and fluid leaks out
51
What can cause increased capillary permeability?
* Substance P, histamine
52
Functions of cardiovascular system? (4)
* Functions
* Distribute dissolved gas and other molecules for nutrition
* Fast chemical signaling
* Dissipate heat by transfer from core to surface of body
* Mediation of inflammatory and host defense responses against invading microorganisms
53
General characterisitics of the cardiovascular system? (4)
* High pressure: left ventricle to capillaries
* Low pressure: capillaries, right side of heart, pulmonary circulation, left atria
* 2 pumps in a series
* Systemic organs arranged in parallel
* Due to the ability to shunt blood to different areas and fine-tune body’s needs (i.e. exercise)
54
Equation for flow?
![]()
55
Explain the variables in the flow equation?
* Q = flow = volume/time
* P = pressure
* R = resistance
* r = radius of circular vessel
* Blood flows through a vessel in a parabolic fashion where the center fluid flows at a higher velocity than the fluid on the sides
* ![]() = viscosity (eta)
* Viscosity is a function of hematocrit, where anemia decreases viscosity and polycythemia vera increases viscosity
* L = length of vessel
56
Resistance in series versus parallel?
* In series, total resistance increases due to additive effect
* Rtotal = R1 + R2 + R3
* In parallel, total resistance decreases due to blood being dispersed through different vessels.
* ![]()
57
Equation that relates flow to cardia output?
Co = change in P/R = stroke volume x heart rate
58
Why is the velocity in capillaries slower than arteries?
* V1A1 = V2A2
* V = velocity
* A = cross-sectional area
* Rationale: capillaries have a large summative cross-sectional area and therefore will have a proportionately lower velocity, whereas the aorta has a smaller cross-sectional area and therefore will have a proportionately higher velocity
* At any moment in time, flow is constant across all of the circulatory system
59
Why does flow oscillate?
In each cardiac cycle, the flow changes depends on the pressure exerted by the contraction of the ventricles (pumps) à pressure changes in the circulatory system à flow oscillates from low to high depending on pressures
60
What isthe average BP?
Average BP = 1/3 (systolic BP - diastolic BP) + diastolic BP
61
How does hydrostatic and gravitational pressure effect blood pressure differences between arteries and veins?
* There is a pressure difference of 85 mmHg between arteries and veins regardless of posture (upright or laying down) or body part (head or feet).
* Reference point is the right atrium
62
Equation for compliance?
C = change in V/ change in P
63
High versus low compliance?
* High compliance – means large change in volume without a large change in pressure
* Low compliance – means small change in volume with a large change in pressure
64
Complaince in blood vessels?
Arteries vs veins?
Purpose?
does it change with age?
* Blood vessels have a finite compliance (volume and pressure can increase only to a certain point).
* Arteries have less compliance than veins (arteries are less compressible because they are thicker and more rigid).
* Purpose
* Want arteries/veins to absorb the blood volume with only a small rise in pressure
* Want to maintain pressure in aorta while the heart refills
* Age
* Younger people have a higher compliance than older people (older people will have more plaque and stenosis)
65
Where does most of the blood volume reside in the cardiovasuclar system?
* Blood volume resides mostly in the systemic circulation
* The largest systemic blood resides on the venous side of the circulation
66
Explian how the pressure changes throughout systemic circulation?
Where does it drop the most?
What acts as the greatest resistors?
* Systemic pressure is much higher than pulmonary pressure
* From the left ventricle (start) to the right atrium (end), pressure drops throughout the vascular system.
* The largest drop occurs between the systemic arterioles and the capillaries at the arteriole sphincters, which regulate blood flow.
* There are many capillaries and very few arterioles relatively à greatest pressure drop
* Precapillary sphincters
* Acts as greatest resistor
* Small cuffs of vascular smooth muscles
* Very responsive to local metabolites
67
Define laminar flow.
Laminar flow: blood flows through vessels in linear vectors
68
Define shear stress
Shear stress: the force of the blood that pulls on the endothelial cells
69
# define turbulent flow
what do they cause
* Turbulent flow: when velocities are high, flow can become chaotic therefore increasing friction and resistance
* Cardiac murmurs result from turbulent flow through abnormal cardiac valves (i.e. stenosis)
70
Explain the principles behind blood pressure measurement.
* When cuff pressure \> systolic pressure, the artery is collapsed.
* When cuff pressure = systolic pressure, artery begins to pulse and can be heard
* Throughout arterial pressure, pulse can be heard.
* When cuff pressure = diastolic pressure, the last pulse is heard.
* \*\*Cannot release cuff pressure too quickly or you may miss the highest pressure at which systolic pressure occurs
71
Importance of Na+/K+ ATPase ?
* Transports 3 Na+ ions out and 2 K+ ions into the cells
* Energy derived from ATPase
* Sets the resting concentration levels of these ions that creates the resting membrane potential
72
Types and importance of Ca++ pumps?
* Types
* Ca2+ ATPase
* Na+/Ca2+ Exchanger
* Maintained at specific concentration because of high equilibrium potential
73
What is resting membrane potential?
At steady state, inside of the cell has a negative potential. Mainly determined by potassium conductance.
74
What are the concentration of different ion in and out of the cell? (na, Ca, Cl. K)
75
Membrane potential?
Difference between the electrical potential inside and outside the cell
76
what is equilibrium potential?
what equation is used for calculation?
* The membrane potential for an ion when it is in the equilibrium
* Ex = 60/z log([xi]/[xo])
77
Explain the basic factors that determine ion flow (3)
* Permeability of the cell membrane
* Concentration gradient
* Transmembrane potential – ions avoid a separation of charge (i.e. negative ions go to positive potential)
78
Equation for Driving force?
what if DF is - or +?
* Driving force = z(Vm – Ex)
* Z is valence charge of ion
* If driving force is + goes out of cell
* If driving force is – goes into cell
79
Explain how channels and pumps are specialized for single ions.
Channels for specific ions will contain selectivity filters that are specific to charge and size
80
What gate is closed during repolarization?
inactivation gate
81
Absolute vs. relative refractory period?
* During repolarization, the relative number of Na+ channels with a closed versus open inactivation gate determines the absolute versus relative refractory period
* Absolute is when too many inactivation gates are closed, not allowing an action potential
* Relative is when just enough inactivation gates are open to allow for membrane depolarization
82
Electrical events in cardiac tissue (5)
1. Depolarize SA (pacemaker) cells (resting Vm = -70mV) à Depolarize atrial muscle from right to left à Depolarize AV (pacemaker) nodal cells
2. Depolarize down the bundle of His (on septum) from left to right
3. Action potential travels down the purkinje fibers to ventricles
4. Depolarize bulk of ventricular myocardium from endocardium to epicardium
5. Ventricles depolarize
83
What makes pacemaker cells unique?
1. These pacemaker cells intrinsically activate (slowly) without the need of external stimulus
1. Phase 4: sloped phase 4 allows for continuous propagation of action potential
2. Phase 0: Modulated Ca++ (Na+ are inactivated)
2. Can be modulated by sympathetic and parasympathetic nervous system
84
What are the 4 phases of Cardiomyocyte Action Potential?
* Phase 4: Vm = -90mV at rest.
* Phase 0: Stimulus causes depolarization à a few Na+ channels open allowing Na+ to enter the cell à Vm approaches threshold potential (-70mV) à more Na+ channels open allowing for steady current of Na+ inwards à massive depolarization
* Phase 1: Brief outward K+ current due to opening of voltage dependent K+ channels à repolarizes cell to 0mV
* Phase 2: Inward Ca++ current due to opening of L-type Ca++ channels à causing a plateau effect sustaining the depolarization of the cell
* K+ flows outward to balance inward Ca++ current
* Phase 3: Ca++ channels inactivate à K+ efflux à repolarization
85
Gap junction role if caridac electrophysiology?
Help coordinate depolarization and speed conduction velocity
86
Explin conduction velocity as it realtes to the cardiac AP?
* As the current flows through the neighboring cardiomyocyte, its potential also rises.
* This can propagate beyond a single cardiomyocyte through gap junctions, but the effect decays as you move further from the first cell.
87
Explian the events occuring the P, QRS and T wave? it terms of what is being deoplarized or repolarized
* Some feature of the heart that are depolarized do not produce a large enough depolarization to be reflected on the EKG
* P-wave: AV node is depolarized
* QRS complex: is the summation of the vectors of depolarization of the cardiomyocytes involved in ventricular contraction
* Positive inflow of current moving from endocardium to epicardium (towards the EKG sensor)
* T-wave: Negative flow of current moving from epicardium to endocardium (away from the EKG sensor)
88
Why is the t wave produce a positive infelection?
This is due to the fact that epicardium is made up cardiomyocytes with different ion channels than the endocardium
Cardiomyocytes in the epicardium have shorter action potential, therefore repolarizing quicker than cardiomyocytes in the endocardium
Negative flow moving away from the EKG sensor creates a positive inflection
