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Flashcards in CV Week 2 Deck (395):
1

_________ is located in the hollow organs of the body and all vasculature except for capillaries and endothelial cells

Smooth muscle

2

Describe structures that have smooth muscle

trachea and airways, vasculature, bladder, female reproductive organs, epididymis and vas deferences, musculature through GI tract, lymphatic vasculature

3

True or false - Because smooth muscle is responsible in a diverse group of organs, it requires a diverse range of regulatory mechanisms to perform specific functions

TRUE

4

In __________, smooth muscle cells all behave independently. Few gap junctions are found in these types of cells because there is no great need to electrically couple.

Multi-unit

5

In __________, smooth muscles behave as one unit which is accomplished by having many gap junctions interconnecting cells.

Single unit

6

Describe body structures that contain
a) multiunit smooth muscle cells
b) single unit smooth muscle cells

a) airways, vasculature, neural regulation
b) GI tract

7

_________ smooth muscle tends to be multiunit, whereas _________ smooth muscle tends to be single-unit

Tonically active, rhythmically active

8

Describe how ADH regulates smooth muscle

ADH is released by posterior pituitary and causes vasoconstriction of smooth muscle (and increased water reabsorption of the kidney)

9

_________ cause contraction, proliferation and remodeling of blood vessels

Inflammatory mediators

10

Nitric oxide is an example of ______________. It is produced in the immediate environment of the muscle and causes vasodilation of the blood vessels.

Humoral or paracrine signaling

11

Describe key differences between smooth muscle and skeletal muscle

Myofilaments in skeletal muscle are more highly ordered and produce bands whereas actin and myosin filaments are arranged differently. Smooth muscle contains dense bodies. Smooth muscles also contract more slowly than skeletal muscle.

12

Why do smooth muscle cells contract more slowly than skeletal muscle?

Cross bridge attachment.detachment is much slower thus rate of contraction is much slower.

13

True/False - although smooth muscle cells contract more slowly than skeletal muscle, smooth muscle cells can achieve equivalent (or greater) peak contractions

true

14

How does slower cross-bridge cycling in smooth muscle affect energy efficiency?

Since cycling of cross-bridges is slower, energy expenditure decreases. This energy efficiency is particularly important to generate sustained contractions over minutes or hours (ie tone)

15

Describe the different types of myogenic activity (intrinsic to the musculature)

phasic with tone (anal sphincter), phasic (colon), tonic (some blood vessels)

16

Describe the steps in activating cross-bridge cycling in smooth muscle.

1) Myosin binds to actin filament and an inorganic phosphate is released
2) Power stroke where actin gets pulled towards middle of sarcomere
3) Rigor (myosin in low energy form). ADP is released and new ATP binds to myosin head.
4) Myosin unbinds from actin. ATP is hydrolyzed.
5) Cocking of myosin head (myosin in high energy form) and ready to bind again.

17

Describe MLCK's role in cross-bridge cycling

MLCK phosphorylates MLC20 (myosin) and facilitates its binding to actin. This facilitates cross-bridge cycling.

18

Describe MLCP's role in cross-bridge cycling

MLCP dephosphorylates MLC20 and reduces cross-bridge cycling --> muscle relaxation

19

What is MLCP activity regulated by?

pathways that in effect regulate Ca++ sensitivity of contractile apparatus

20

What determines the force and duration of contraction?

The balance between myosin phosphorylation and dephosphorylation; therefore, the balance btwn activity of MLCK and MLCP

21

How does Ca++ vary in when there are a) high MLCK levels; b) high MLCP levels

a) high MLCK - high Ca++; b) high MLCP - low Ca++

22

_________ (2) are examples of excitatory agonists that cause Ca++ sensitization and thus greater force by inhibiting MLCP

Rho Kinase and PKC

23

_________ (2) are examples of inhibitory agonists that reduce Ca++ sensitization and thus relax muscle, reducing the force by aggravating MLCP activity

cAMP and cAMP dependent mechanisms

24

What are three pharmacological agents that are excitatory agonists in regulation of contraction via pharmacochemical coupling?

Ach, norepinhephrine, substance P

25

What are two pharmacological agents that are inhibitory agonists in regulation of contraction via pharmacochemical coupling?

adenosine, vasoactive inhibitory peptide

26

How do ROCK and PKC inhibit MLCP activity and thus stimulate contraction?

ROCK phosphorylates MYPT1 subunit of MLCP and PKC via Ca++ and PLC-b mechanism phosphorylates CPI-17,(inhibitory proteins)

27

Smooth muscle cells contains transport proteins and organelle membranes that set and regulate membrane potential, generate excitable events and ___________________

Ca++ entry into and removal from the cytoplasm

28

Like other excitable cells, the PM has some level of permeability of each ion species present. The dominant membrane permeability in smooth muscle is due to ______________

K+ channels

29

RMP is smooth muscle is usually _________ mV

-40 to -80

30

_________ couple smooth muscle cells into an electrical syncytium and provide low electrical resistance pathways between cells

Gap junctions

31

Describe the structure of a gap junction.

Gap junction is contains numerous CONNEXONS which are channels assembled by six connexin proteins each that form the pore.

32

Glucose, glutamine, ADP, adenosine, and cAMP all have same ________ through connexins

permeability

33

What happens to connexons when they are attached to a damaged cell?

They close, can be regulated somewhat by Ca++ and pH

34

Name 4 types of K+ channels found in smooth muscle cells

voltage-dependent K+ channels (Kv), Ca++ activated K+ channels (BK), 1 transmembrane pore formign loop (Kit, Katp), and 2 transmembrane forming loops (K2p)

35

Ca++ entry (excitation) tends to be controlled by __________.

K+ channels, due to their importance in regulating membrane potential

36

________ are voltage-independent channels that are important for resting or basal K+ conductance. They contribute to the resting potential of the smooth muscle cells.

2 pore K+ channels (K2p)

37

High expression of _________ can reduce the tendency for smooth muscle cells to generate action potentials, making the muscle less excitable

Voltage-activated K+ channels

38

High abundance of ____________ can lead to rhythmic patterns of activity. These channels are also important for large amplitude hyperpolarizations produced by some inhibitory neurotransmitter as well as some other agonists.

Ca++ activated K+ channels (ekg BK)

39

____________ are active in negative voltage range and therefore also contribute to a more hyperpolarized cell. They also mediate responses to some inhibitory agonists.

Inward rectifiers (Kir)

40

Ca++ entry is controlled by _______ because these channels set or regulate membrane potential that determines Ca++ entry via __________

K+ channels, voltage dependent Ca++ channels

41

Depolarization induced activation of ____________ lead to Ca++ entry and contraction of smooth muscle

L-type Ca++ channels

42

________ is a Ca++ channel blocker. When added, the muscle relaxes because the __________ have been shut down.

Nifedipine, L-type Ca++ channels

43

Describe the two ways which Ca++ stimulates cell to depolarize

Ca++ activates Cl- to leave the cell --> depolarization and Ca++ activates non-selective cation channels --> depolarization

44

Describe how Ca++ causes hyperpolarization of the cell

Activates BK to transport Ca++ out

45

Describe Ca++'s role in CICR

Ca++ enters cell and stimulates Ca++ induced Ca++ release in sarcoplasmic reticulum

46

Describe how depolarization leads to contraction via Ca++ channels

depolarization causes an increase in Cav channels opening which increases Ca++ entry

47

Describe how hyperpolarization leads to decreased contraction via Ca++ channels

Decrease in open Cav channels which leads to decreased Ca++ entry and therefore decreased contraction

48

There are three major mechanisms that reduce Ca++ and that relaxation of smooth muscle depends on. What are they?

ATP-driven SR Ca++ pump, AT driven PM Ca++ pump, and Na/Ca exchange (NCX, uses Na+ gradient).
The more minor mechanisms are Ca++ binding molecules in cytoplasm and active Ca++ transport in mitochondria.

49

_______ is a short-acting gas and free radical whose unpaired electrons cause this chemical to be highly chemically reactive

Nitric Oxide

50

The biological actions of nitric oxide are rapidly terminated due to what? This makes this compound short-acting. It must be synthesized on demand.

Spontaneous oxidation to NO2 and NO3 resulting in a bio half life of around 3-5 seconds.

51

Nitric oxide is highly ______ so its post-junctional effector proteins are typically within the cell.

lipophilic

52

True or false: NO can be synthesized by variety of different cell types

True

53

The highest levels of nitric oxide in the body are found in the _______

neurons

54

Describe how nitric oxide inhibits smooth muscle contraction.

Vasodilator binds receptor on endothelial cell which activates NOs. NO is produced from Arginine. NO rapidly diffuses across membranes to a smooth muscle cell. It binds guanylyl cyclase which increases cGMP concentration and leads to relaxation of the smooth muscle cell.

55

In the NO pathway, cGMP activates _____________ which then goes on to phosphorylate several proteins important in promoting vasodilation

cGMP dependent protein kinase (PKG)

56

How do proteins phosphorylated by PKG promote vasodilation? (3 ways)

Proteins inhibit Ca++ release from IP3 receptors; proteins inhibit activation of L-type Ca++ channels; proteins increase Ca++ uptake by SR. These three mechanisms all lead to more highly activated MLCP (Ca++ desensitization)

57

What are the lateral leads?

I, V5, V6, AVL

58

What are the inferior leads?

Lead II, Lead III, avF

59

What are the anterior or septal leads?

V1-V4

60

How would you determine that rhythm is in normal sinus?

Upright P wave in inferior leads (lead II, lead III, aVF) [biphasic wave in lead VI - in textbooks]

61

How would you determine if there is a left axis deviation?

R wave in lead I is pointing upward (+) and R wave in lead II is pointing downward (-) (left each other)

62

How would you determine if there is right axis deviation?

R wave in lead I is pointing downward (-) and R wave in lead II is pointing upward (+) (right at each other)

63

How long is a normal PR interval?

less than 200 msec or 1 big box

64

How long is a normal QRS?

less than 120 msec or 3 little boxes

65

How long is a normal QTc?

Corrected for heart rate, should be 1/2 of R-R interval, <450 msec or 2.5 big boxes

66

If there is no correlation between the P wave and QRS and PR interval varies BUT P-P intervals and R-R intervals are consistent, what condition does this indicate?

3rd degree heart block

67

If the PR interval gets progressively longer until a QRS is dropped, what condition does this indicate?

2nd degree heart block, mobitz type I

68

If the PR interval is consistently longer than 200 msec (one big box), what condition does this indicate?

1st degree heart block

69

If the PR interval is consistent but a QRS is dropped randomly, what condition does this indicate?

2nd degree heart block, mobitz type II

70

The ____ is ALWAYS the first downward deflection in the QRS complex. If there is no downward deflection, then it doesn't exist

Q wave

71

Why is a prolonged QTc medically significant?

If ventricles attempt to depolarize or contract on top of a Q wave, this leads to serious dysrhythmias such as V-fib and V-tach

72

What happens in right atrial enlargement?

right atrial depolarization lasts longer than normal and its waveform extends to end of left atrial depolarization (uneven double hump with taller 1st hump). P wave is taller than normal although width remains unchanged.

73

What happens in left atrial enlargement?

left atrial depolarization lasts longer. Amplitude is unchanged. Height remains same but duration is longer than 120 msec (3 little boxes). NOTCHED WAVE ("p mitrale") near peak in lead II

74

What does an inverted T wave indicate?

ischemia

75

What does a spiked T wave indicate?

hyperkalemia

76

_______ are wide, random QRS complexes that usually come in early and can be unifocal or multifocal

Premature ventricular complexes

77

In _______ every other beat is a PVC whereas in _______ every 3rd beat is a PVC

bigeminy, trigeminy

78

What varies in a sinus arrhythmia?

R-R intervals

79

In a ____________ the heart beat happens sooner than expected. P waves are present and QRS complex is no different than baseline.

premature atrial complexes

80

In _________ there is an irregularly irregular rhythm and ___________ vary without any pattern. There is also an absence of _______ . Atrial HR can run 400-500 bpm.

atrial fibrillation, R-R intervals, P waves

81

In a _________, P wave is often inverted (esp in lead II) but may be under or after QRS and the heart rate is slow.

junctional rhythm

82

What differentiates between high junctional rhythm (stable) and low junctional rhythm (unstable)

Narrow QRS suggests stable (high) whereas wide QRS suggests unstable (low)

83

In __________ there is a narrow QRS (less than 120 ms or 3 small boxes) and heart rate of over 100 bpm. If there is a wide QRS, what is this called?

supraventricular tachycardia; SVT with aberrancy (typical in younger patients)

84

_________ is a wide complex tachycardia that is typically in older patients with previous myocardial infarction

ventricular tachycardia

85

In __________, there are no QRS complexes. This represents a chaotic and mechanical cardiac arrest.

ventricular fibrillation

86

A ___________ is can be seen in leads I, II, AVL, V1-V6 and represents a previous MI. In which leads does this deflection not represent pathology?

pathological Q wave, not pathology in leads III and AVR.

87

______________ is a reentry tachyarrhythmia via accessory pathway.

Wolf-Parkinson White

88

What accessory pathway is usually seen in WPW?

"Bundle of Kent" located between atria and ventricle on side. This electrical signal goes through without delay in AV node and meets the normal signal in ventricular purkinje.

89

What is diagnostic for WPW?

PR less than 125 ms (3 small boxes) and at least one delta wave.

90

How does WPW cause tachyarrhythmia (2 ways)

Narrow complex - the abnormal signal returns and depolarizes AV node, causing it to fire before the SA node.
Wide complex - abnormal signal hits AV node during its refractory period. Will pass through all the way around and come back to AV node in retrograde fashion.

91

What are common symptoms of WPW?

unexplained syncope and palpitations infrequently. Normal risk not high except if there's abnormal pathways.

92

Drugs such as digoxin, Beta-blockers, verapanil, and adenosine will make WPW worse. Why?

Work mainly on AV node not on accessory pathway

93

What drug and surgical treatments are used for WPW?

Procanamide and Amiodarone. Surgical catheter ablation to damage accessory pathway.

94

What are the most common congenital defects?

Heart followed by genital/urinary tract

95

Describe the pathway of cardiac progenitor cells to the mesoderm

Cardiac progenitor cells form in epiblast then migrate in cranial --> caudal order through the primitive streak to the SPHLANCNIC LATERAL PLATE MESODERM

96

Where do prospective myoblasts and hemangioblats reside?

in the SPHLANCNIC MESODERM in front of the neural plate and on each side of th emebryo

97

In formation of the heart tube, angiogenic cell clusters initially coalesce to form ______________

right and left endocardial tubes [ endothelial heart tubes ]

98

After the embryo folds ________ and __________, the endocardial tubes fuse via ________ to form the heart tube

cardiocaudally, laterally, programmed cell death

99

Describe the four layers of the primitive heart from inside to outside

endocardium, cardiac jelly, myocardium, epicardium (outside covering of the tube)

100

The cardiac jelly is a thick, acellular material made by ____________

myocardium

101

In the epicardium, _______ migrates from the septum transversum to form the ____________

mesothelium, coronary arteries

102

On day 18, the endocardial tubes and dorsal aortae are formed between what two layers?

endoderm and sphlancnic mesoderm

103

On day 22, the embryo is in the __________ and fusion occurs only the ______ region of the horseshoe shaped heart tube

8 somite stage, caudal

104

What structures rise from the crescent portion of the horseshoe shaped heart tube?

outflow tract and most of ventricular region

105

In 22-day embryo, _____________ drain the yolk sac

vitelline veins

106

In 22-day embryo, __________ carry O2 from the placenta

umbilical veins

107

In 22-day embryo, _______________ drain body wall and head

common cardinal vein

108

True or false: The inflow and outflow tracts are connected to the heart tube before any cardiac folding takes place

True

109

Around day 23, the _______ begins to form from a series of expansions, constrictions and fold

cardiac loop

110

What are the four initial dilations of the heart tube?

sinus venosus, primitive atrium, primitive ventricle, bulbus cordis

111

What two features of the heart does the cardiac loop create?

1) normal position of heart chambers; 2) changes a single circuit system into an asymmetrical circuit system with pulmonary and systemic circulations

112

At day 24, remodeling of the _______ begins with a shift to the right of venous return

sinus venosus

113

What does the right vitelline vein give rise to?

inferior vena cava

114

What does the right anterior cardinal vein give rise to?

superior vena cava

115

What does the left sinus horn give rise to?

coronary sinus and oblique vein of the left atrium

116

The right sinus horn blends into the right posterior wall of the right atrium to become the smooth area _____________

sinus venarum

117

What three vessels open into sinus venarum?

THINK RIGHT ATRIUM. Inferior vena cava, superior vena cava, coronary sinus

118

The sinus venarum contains the ___________ which act as conducting fiber tract from SA node to AV node

crista terminalis

119

_________ are found in the cardiac jelly where they are described as "swellings"

endocardial cushions

120

What germ tissue are endocardial cushions derived from?

sphlancnic mesoderm

121

The sphlancnic mesoderm (endocardial cushions) and __________ in the conotruncal area play a role in formation of the _____________

neural crest cells, septa and valves

122

Endocardial cushions are important because they play a role in __________

cardiac defects

123

The primitive atrium is partitioned between the right and left _________

endocardial cushions

124

During partitioning of the primitive atrium, a thin membranous septum called the __________ because the right and left endocardial cushions

septum primum

125

After the formation of the septum primum, programmed cell death forms the ________

ostium secundium

126

What is the role of the ostium secundium?

Maintains the right to left shunt bypassing the pulmonary circulation

127

What thick muscular septum forms to the right of the septum primum?

Septum secundum

128

The ________ forms in the septum secundum which maintains the right to left shunt

Foramen ovale

129

When does the foramen ovale close?

immediately after birth

130

At birth, closure of the foramen ovale is functiona. Describe what this means in terms of atrial pressure.

At birth, there is a decrease in right atrial P from occlusion of placental circulation and increase in left atrial pressure due to increased pulmonary venous return (USING LUNGS)

131

When does the anatomical closure of the foramen ovale occur? What two structures fuse?

Occurs at 3 months, septum primum and septum secundum fuse

132

Incomplete anatomical fusion of septum primum and septum secundum causes ____________. This is present in 25% of the population and clinically usually of no importance.

probe patency of foramen ovale

133

Defects in the ________ cause the most clinically significant atrial septal defects and are prevalent in females to males in a _____ ratio

ostium secundum, 2:1

134

The cor triloculare biventriculare is also known as the _______

common atrium

135

What four heart defects do endocardial cushions play a role in?

atrial septal defect, ventricular septal defect, transposition of the great vessels, tetralogy of fallot

136

Conotruncial cushions, which also contain neural crest cells, play a role in both heart and _________ defects

craniofacial

137

During partitioning of the atrioventricular canal, what do the four endocardial cushions form(3)

septum , bicuspid valve, tricuspid valve

138

During partitioning of the atrioventricular canal, what can go wrong (2)

persistent common atrioventricular canal and abnormal division of the canal

139

The truncoconal septa form from _________ that migrate from the hindbrain through pharyngeal arches ___, 4, and 6 and then invade the truncus arteriosus to form the septa.

neural crest cells, 3

140

During the fifth week, _____ ridges/swellings appear and go on to form the ________________ which divides the truncus into the aortic and pulmonary channels

truncal, aorticopulmonary septum

141

After formation of the truncal swellings, _____ swellings also form which give rise to the _________________

conal, outflow tracts of right and left ventricles

142

_________ contribute to both swellings to form connective tissue and smooth muscle of aorticopulmonary system

neural crest cells

143

During partitioning of the truncus arteriosus and the bulbus cordis, _______ lines up the correct outflow tract with the correct ventricle

spiraling

144

During partitioning of the truncus arteriosus and bulbus cordis, If neural crest cells were to be experimentally removed or blocked during their migration this would lead to ___________

persistent truncus arteriosus

145

If there is no aorticopulmonary septum formed, then there will be ________

persistent truncus arteriosus

146

If the aorticopulmonary septum does not spiral there will be ____________

transposition of the great vessels

147

If the aorticopulmonary septum is misaligned there will be ___________

tetralogy of fallot

148

Persistent truncus arteriosus is normally accompanied by __________

ventricular septal defect

149

In persistent truncus arteriosus, which great vessel gets more blood flow and why?

The pulmonary artery section receives more blood flow than the aorta section due to decreased pressure in the lungs compared to systemic circulation.

150

Describe the basic pathology of persistent truncus arteriosus.

In persistent truncus arteriosus, the great vessels do not separate and there is a VSD. Deoxygenated and oxygenated blood mix and go into body and lungs.

151

In persistent truncus arteriosus, since the pulmonary artery section receives more blood than aorta, what happens that leads to pulmonary HTN?

Too much blood in the lungs leads to fluid build up which makes it difficult to breathe. Blood vessels to the lungs become damaged. This makes it harder to pump blood into the lungs over time due to pulmonary HTN that develops.

152

Due to pulmonary HTN, more blood starts to go into the body then the lungs eventually in persistent truncus arteriosus. What occurs as a result?

Cyanosis worsens as blood with lower O2 travels to the body.

153

How is persistent truncus arteriosus treated?

corrective surgery needed within 6 months of life - closure of VSD and separation of great vessels

154

Infants with transposition of the great vessels can only survive after birth if they have one of which 3 defects?

patent ductus arteriosus, atrial septal defect, ventral septal defect - allows intermixing of the blood

155

If these defects are not present, how can they be surgically induced?

Cardiac catheterization (balloon atrial septostomy) may create large hole in the atrial septum or a patent ductus arteriosus can be clinically induced to remain open allowing blood flow btwn pulmonary artery and aorta

156

Describe the basic pathology of transposition of the great vessels.

The great vessels are switched so the aorta is connected to the right ventricle and the pulmonary trunk is connected to the left ventricle - therefore oxygenated blood going to lungs and deoxygenated blood going to systemic circulation - NOT COMPATIBLE WITH LIFE

157

During the arterial switch procedure, what remains attached to the aorta?

coronary arteries

158

Transposition of the great vessels is usually accompanied by an _____________

atrioseptal defect

159

______________ the most common cyanotic heart defect

teratology of fallot

160

Describe the basic pathology of teratology of fallot

The outflow tract openings fail to align with the ventricles. Right ventricular outflow (pulmonary artery) is blocked which causes pulmonary stenosis and an overriding aorta. A ventricular septal defect accompanies.

161

The ventricular septal defect and pulmonary stenosis in TOF leads to high pressure in the ___________ which results in ____________

right ventricle, right ventricular hypertrophy

162

In extreme situations, right ventricular outflow tract is completely blocked, which leads to teratology of fallot and _________

pulmonary artesia

163

Children with teratology of fallot are at risk of having what kinds of spells??

Hypercyanotic spells due to spasm of infindibular region (below pulm vave) and/or sudden increased pulmonary vascular resistance which produces a sudden decrease in amount of blood getting to lungs.

164

What kind of shunt develops in teratology of fallot? How does this lead to acidosis?

Right to left shunt which means more deoxygenated blood is going into systemic circulation. This further increases pulmonary vascular resistance which leads to acidosis.

165

Older children learn to prevent or alleviate symptoms by squatting. What is squatting believes to do?

Squatting kinks the large arteries in the lower extremities which increases systemic vascular resistance and forces more blood across the pulmonary outflow tract.

166

What are the four components of teratology of fallot? Which is the primary problem?

Ventricular septal defect (VSD), pulmonary stenosis, overriding aorta, thickening of the right ventricle. VSD is primary problem.

167

During partitioning of the primitive ventricle, where does the muscular ventricular septum develop?

midline on floor of primitive ventricle

168

The __________ is located between the free edge of the muscular interventricular septum and fused AV cushions

interventricular foramen

169

Closure of the interventricular foramen via completion of the conus septum and outgrowth of tissue from the inferior endocardial cushion leads to formation of the ____________

membranous interventricular septum

170

In other words, membranous interventricular septum is formed when the proliferation of right and left ____________ combined with proliferation of inferior (AV) endocardial cushion closes the interventricular foramen.

right and left bulbar ridges (conus cushions)

171

_____ are the most common cardiac congenital defects, occurring in about 30% of cases

ventricular septal defects

172

What is the most common cause of ventricular septal defect?

membranous IV septum does not form

173

Single or multiple perforations in the ______________ can also cause ventricular septal defects

muscular interventricular septum

174

Describe the two mechanisms of no shunt (acyanotic) congenital heart defects

(1) anomaly of aortic arches, (2) coarctation of aorta

175

Describe three types of anomalies of aortic arches

right arch of aorta, double arch of aorta, retro-esophageal right subclavian artery

176

Describe the three mechanisms of left to right shunt (acyanotic) congenital heart defects

persistent ductus arteriosus, interatrial septal defects, interventricular septal defects

177

Describe the three mechanisms of right to left shunt (cyanotic) congenital heart defects

(1) complete transposition of the great vessels, (2) truncus arteriosus communis (persistent), (3) teratology of fallot

178

The smooth portion of the left atrium houses the _______________

pulmonary veins

179

Remodeling of the vascular system generally occurs from ______ to ________ tracts

inflow, outflow

180

For the inflow tract, above the diaphragm, remodeling begins with a shift to right of venous return. This leads to formation of what 5 structures?

IVC, SVC, coronary sinus, oblique vein of left atrium, sinus venarum

181

For the inflow tract, below the diaphragm, the vitelline system gives rise to what structures? (3)

liver sinusoids (incl ductus venosus), the portal system (portal vein, SMV, IMV) and a portion of the inferior vena cava.

182

For the inflow tract, below the diaphragm, what occurs to the right and left umbilical veins?

The right umbilical vein disappear and the left umbilical veins anastomoses with the ductus venosus in the liver.

183

Anastomosis of the left umbilical vein with the ductus venosus in the liver results in what?

Shunting of oxygenated placenta blood into inferior vena cava and right side of heart

184

The _________ form a portal system that drains the blood from the foregut, midgut, and upper part of anorectal canal

right and left vitelline veins

185

For the outflow tract, ventrally, the aortic arch arteries rise from the _________ through expansion of cranial end of the __________

aortic sac, truncus arteriosus

186

Dorsally, the aortic arches connect to left and right ______

dorsal aortae

187

What develops from aortic arches 3,4, and 6 (and R and L dorsal aortae)?

adult arterial system, ASYMMETRICAL arches

188

Aortic arch 6 remains on left side and goes on to form what?

pulmonary vessels and ductus arteriosus

189

What can maintain a patent ductus arteriosus if clinically indicated?

exogenous prostaglandins

190

Small pactent ductus arteriosuses can be closed via what?

prostaglandin inhibitors such as indomethacin or ibuprofen

191

What two main reasons necessitate closure of PDA?

(1) large size of ductus --> large volume of blood going into lungs can lead to overload --> heart enlargement then failure; (2) avoid risk of developing endocarditis

192

Development of endocarditis in ____ of patients with PDA will lead to an increased mortality of 50%

1/8

193

In fetal circulation, well oxygenated blood returns from the placenta via the ________

umbilical vein

194

In fetal circulation, what two pathways does blood travel in from placenta?

1/2 of blood passes through hepatic sinusoids whereas other half bypasses the liver and goes through the ductus venosus into the inferior vena cava

195

What are the two right to left shunts in fetal circulation?

(1) blood from right atrium goes through foramen ovale into left atrium; (2) the small amount of blood from right ventricles that enters the pulmonary trunk passes through ductus arteriosus into the aorta.

196

In fetal circulation, blood flows from right to left atria via foramen ovale and then into the ascending aorta. What tissues are best oxygenated this way?

head, neck, upper limbs

197

How is blood in placental circulation re-oxygenated?

Blood is returned via umbilical arteries to the placenta

198

At birth, what three shunts cease to function?

foramen ovale (interatrial), ductus arteriosus (inter great vessel) and ductus venosus (bypass lungs)

199

What causes the foramen ovale to close upon birth?

Aeration of the lungs provides a dramatic fall in vascular resistance. An increase in pulmonary blood flow leads to increased L atrial pressure above that in R atrium which closes foramen ovale.

200

Upon birth, what happens to the ductus arteriosus and ductus venosus?

constriction

201

What are the remnants of umbilical arteries upon birth?

internal iliac arteries and media umbilical ligaments

202

What are the remnants of the umbilical vein upon birth?

ligamentum teres of liver

203

What are the remnants of ductus venosus upon birth?

ligamenetum venosum

204

What are the remnants of the foramen ovale upon birth?

Fossa ovalis (becomes obliterated?)

205

Circulation is a __________ that features a branching pattern and blood flows through serial and parallel paths

closed circuit

206

True/False -In all cases blood flows through 2 capillary beds in series

false, sometimes blood flows through a single capillary bed and sometimes it flows through an arrangement of parallel and series paths

207

What pathway does blood from the right to the left heart take?

It can only take a single pathway, across a single capillary bed in the lungs.

208

Sometimes, in the normal human body, some deoxygenated blood (which should have gone to right heart) mixes with oxygenated blood bound to ______________

systemic arteries

209

_________ transport blood under high pressure, have rapid pulsatile blood flow and are densely innervated. These vessels have a strong muscular wall.

arteries

210

________ are the smallest branches of arteries.

Arterioles

211

Arterioles are major ______________ of whole peripheral circulation and have a ________ layer

resistance vessels, thick smooth muscle

212

Arterioles are ________ innervated and have a _________ layer

very densely, endothelial cell

213

Arterioles regulate blood flow to ________

capillary beds

214

Arterioles are considered "_______________" due to having the biggest P drop

stopcocks of circulation

215

In arterioles, how is basal tone established?

smooth muscle is partially contracted under normal conditions

216

True/False: Arterioles are the most significant point of control over peripheral resistance to flow

True

217

True/False: Arterioles outnumber any other type of artery

True

218

True/False: Arterioles are less muscular in proportion to their diameter

FALSE - arterioles are more muscular in proportion to their diameter

219

Arterioles are highly capable of changing their ______

radius

220

How is blood flow to the capillaries controlled?

via vasoconstriction and vasodilation

221

What is the difference between skeletal muscle and vascular smooth muscle in terms of tone?

Vascular smooth muscle has some tone without needing neural input.

222

The basal tone seen in smooth muscle comes from _________ and ________ factors

intrinsic, local

223

All types of smooth muscle cells exhibit _________ channels which are typically _______ which are activated by the cell's membrane potential

voltage-dependent Ca++, L-type Ca++ channels

224

Cells that sit negative to ________ must be depolarized in order to be activated by L-type Ca++ channels

-60mV

225

Cells that are positive of -60mV have some ______ activation of L-type channels and therefore ______ Ca++ entry

tonic x2

226

True/False: Capillaries have smooth muscle

FALSE - CAPILLARIES DO NOT HAVE SMOOTH MUSCLE

227

Describe the features of capillary walls.

Very thin walls consisting of a single layer of endothelium permeable to small molecular substances.

228

Name three features of capillaries.

1) major exchange vessels, 2) largest total cross-sectional area, 3) low flow velocity

229

__________ are small vessels with thin walls that collect blood from capillaries and also participate in exchange

venules

230

What happens when blood enters venules from capillaries?

total cross-sectional area diminishes and thus the velocity of blood flow increases

231

Venules progressively merge to form larger _____ which transport blood _________

veins, back to heart

232

Veins are major ________ vessels and a major ______ reservoir.

capacitance (major collection and storage site for blood), controllable

233

Describe three features of veins

1) thin but muscular walls, 2) under low pressure, 3) densely innervated

234

About _____ of entire blood volume of body is in systemic circulation and about _____ is in heart and lungs

85, 15%

235

Describe the distribution of the blood in circulation

65% in veins, 13% in arteries, 7% in arterioles and capillaries

236

_________ is the total area of all vessels added together at each _____ in the circulatory stem

cross-sectional area, level

237

Blood velocity is measured in a __________ at each ______ in the circulatory system

single vessel, level

238

_________ markedly affects blood velocity

vessel radius/diameter

239

The highest velocity is found in the _____ which also has the lowest cross-sectional area

aorta

240

The lowest velocity is found in the _______ which has the highest cross-sectional area

capillaries

241

Veins have ____ velocity and ____ area

higher, lower

242

True/False: Capillaries have 1000x the cross sectional area of aorta

true

243

What is the formula for velocity of blood flow?

velocity is equal to blood flow divided by cross sectional area

244

Describe the relationship between velocity, blood flow and cross-sectional area

Velocity is proportional to blood flow and inversely proportional to cross-sectional area

245

Describe the three reasons why blood velocity decreases from aorta to capillaries

1) greater distance means more friction to reduce speed, 2) smaller radii of arterioles and capillaries offers more resistance, 3) farther from heart, total cross sectional area becomes greater and greater

246

Describe fluctuation of the arterial pressure in regards to pulsatile heart pumping

The arterial pressure in aorta is high because heart is pumping constantly. However, it is higher in the systolic phase than diastolic phase.

247

__________ is the force exerted by the blood against any unit area of the vessel wall

blood pressure

248

As blood flows through systemic circulation, pressure decreases progressively because of the _________

resistance to blood flow

249

Intravascular pressure stretches blood vessels in proportion to their _________

compliance

250

Largest decrease in pressure occurs across the _________ because they are the site of highest resistance

arterioles

251

What is pulse pressure?

the difference between peak arterial pressure of systole and peak arterial pressure of diastole

252

How is pulse pressure dampened over the course of the arterial tree? (2)

1) compliance of arterial walls, 2) resistance to flow as vessel diameter becomes smaller.

253

Due to the hydraulic filter effect, the flow through capillaries will be ________ thoughout the cardiac cycle

continuous

254

What is compliance?

the elasticity of vessel walls

255

True/false: Capillary blood flow is non-pulsatile

True - due to increasing dampening by vessel compliance and functional resistance of small arteries and arterioles

256

In Grave's disease, in addition to hyperthyroidism and elevated basal metabolism, what changes are seen in arterioles?

Arteriolar vasodilation and reduced arteriolar resistance - causes a dampening effect on pulsatile arterial pressure which diminishes it. Pulsatile flow observed in capillaries of nail beds.

257

_________ is the lowest arterial pressure during the cardiac cycle

Diastolic P

258

The most important determinant of pulse pressure is __________

stroke volume.

259

The arterial pulse P gives valuable clues about a person's pulse pressure, unless what?

arterial compliance is not normal

260

Describe the arterial pulse pressures and stroke volumes found in those with severe CHF and severe hemorrhage

small arterial pulse pressures because their stroke volumes are abnormally small

261

Describe the arterial pulse pressure and stroke volume found in those with aortic regurgitation

large stroke volume, increased arterial pulse P

262

Describe the stroke volumes in trained atheletes

Have high stroke volumes at rest because their HRs are usually low due to prolonged ventricular filling times

263

What are the two factors that dampens pulse P over the course of arterial wall tree?

compliance and resistance to flow as vessel diameter becomes smaller

264

______________ is the avg arterial pressure with respect to time

mean arterial pressure (MAP)

265

What is the formula for MAP?

=1/3 pulse pressure + diastole P; or (1/3 systolic-diastolic) + diastolic; or 1/3 systole + 2/3 diastolic

266

Describe why venous P tends to be low.

Veins have a high capacitance and can hold large volumes of blood and lower pressure.

267

True/False: atrial pressure is even lower than venous pressure

true

268

Atrial pressure can be estimated by the __________ [approximately equal]

pulmonary wedge pressure

269

True/false: Absolute pressure drives blood flow

FALSE - pressure gradient - blood flows from high P to low P

270

___________ is the quantity of the blood that passes a given point in circulation in a given period of time

blood flow

271

What is the formula for blood flow

Blood flow is equal to the pressure gradient divided by resistance. Also can be mean arterial pressure / resistance

272

Blood flows when?

pressure exceeds resistance

273

_____________ is the total quantity of blood that can be stored in a given portion of the circulation for each mmHg pressure rise

compliance

274

What is the formula for compliance/capacitance?

Compliance is equal to the volume divided by the pressure

275

True/False: Capacitance is much greater in arteries than veins

FALSE, much greater in veins

276

Capacitance/compliance is determined in large part by the relative proportion of __________ to __________ in the vessel wall

elastin fibers, smooth muscle and collagen

277

True/False: Aging decreases compliance

true. As a person ages, the arteries become stiffer and less distensible.

278

Artherosclerosis results from the deposition of tough, rigid _______ inside the vessel wall and around the atheroma. This increases stiffness and decreases the elasticity of the artery wall.

collagen

279

________ is the force that impedes blood through the system

resistance

280

What factors change the resistance of blood vessels? (3)

blood viscosity, blood vessel length, radius of the vessel

281

How is resistance in blood vessels calculated?

resistance is equal to 8*blood viscosity * blood vessel length divided by pi*radius^4 (R = 8nl/pi*r^4)

282

What blood cells/proteins elevates blood viscosity the most? In that regard, what conditions elevate blood viscosity?

RBC count and albumin, polycythemia and dehydration

283

What decreases blood viscosity?

anemia and hypoproteinema --> increased blood flow

284

What declines with distance in terms of blood vessels?

pressure and flow

285

What is the most powerful influence over blood flow?

vessel radius - only significant way of controlled resistance - marked affects blood velocity

286

________ are changes in vessel radius

vasoreflexes

287

Smooth muscle in which blood vessel layer contracts during vasoconstriction?

tunica media

288

What is the major determinant of resistance in blood vessels and why?

Changes in the radius of vessels because the viscosity of blood or length of blood vessel cannot be easily changed from moment to moment

289

What is the relationship between blood flow and radius of vessel?

Blood flow is proportional to the 4th power of radius and therefore small changes in vessel radius cause large changes in flow (ml/min)

290

Inhibition of sympathetic activity ______ blood vessels and _____ blood flow whereas very strong sympathetic activity _____ blood vessels and _____ blood flow

dilates, increases, constricts, decreases (sometimes down to 0 despite high arterial P)

291

An increase in arterial pressure would cause what in regards to blood flow? Why?

a proportional increase in blood flow.

292

Why is blood flow at arterial pressure of 100mmHg usually 4-6X as a great as blood flow at 50 mmHg instead of 2X?

There is an effect of increased pressure on increased vascular diameter. Increase in arterial pressure increases the force that pushes blood through the vessel but also distends the vessels at the same time which decreases vascular resistance

293

What is the largest proportion of resistance contributed to?
a) arteries
b) arterioles
c) capillaries

arterioles

294

Describe blood flow and pressure for blood vessels in series.

Each blood vessel in series receives same total blood flow and as blood flows through the series of blood vessels, pressure decreases.

295

True or false: For a given system, total resistance is less than the resistance of any of the individual arteries.

TRUE

296

What is the equation for total resistance in parallel?

1/Rtot = 1/Ra + 1 Rb.. 1/Rh

297

Describe blood flow and pressure for blood vessels in parallel

Each artery in parallel receives a fraction of total blood flow. In each parallel artery, the pressure is the same.

298

Where is series resistance found?

Illustrated by the arrangements of blood vessels within a given organ

299

Where is parallel resistance found?

illustrated by systemic circulation (arteries branching off aorta)

300

The ___________ is the complete resistance that blood encounters as it flows from arterial to venous side of circulation

total peripheral resistance

301

The ______ is the resistance that blood encounters as it flows from capillaries back to the heart

venous resistance

302

__________ is fluid's resistance to flow, "thickness," or internal friction of the fluid

viscosity

303

What are the three factors that influence blood viscosity?

hematocrit, temperature, flow rate

304

What change in the following would cause blood viscosity to increase?
A) hematocrit
B) temperature
C) flow rate

A) increase in hematocrit, B) decrease in temperature, C) flow rate decrease (non-newtonian flow)

305

Blood behaves as a non-newtonian fluid which means that its viscosity changes as a function of _________

shear rate (velocity)

306

TRUE/FALSE: When blood moves quickly as in peak systole, it is thicker whereas when blood moves slowly during end-disastole, it is thinner.

FALSE - faster=thinner. RBC's are sticky and aggregate at slower speeds.

307

What is polycythemia vera and how does it affect blood viscosity?

Polycythemia vera is a condition where there is increased RBC production from the bone marrow. This would increase blood viscosity (increased hematocrit).

308

How does whole body hypothermia during surgery affect blood viscosity?

It increases blood viscosity and increases resistance to flow due to decrease in temperature

309

How is blood viscosity affected during circulatory shock?

There is very low flow in the microcirculation causing increased cell to cell and protein to celll adhesive interactions --> increased viscosity

310

When laminar flow occurs, where is velocity of flow greatest?

Greatest in center of the vessel than toward the outer edges. FLOWS IN LAYERS, FASTER IN CENTER.

311

True or false: Flow is always proportional to driving P.

FALSE - only under laminar flow conditions

312

Where is velocity of flow lowest in laminar/streamline flow?

At vessel wall

313

__________ occurs when red blood cells move toward the center of the blood vessel in response to increased flow rate. This lowers apparent viscosity of blood.

Axial streaming

314

In _______ flow the blood flows in all directions in the vessel. Where are the fastest velocities found?

turbulent flow, fastest velocities not necessarily in the middle of the stream

315

True/False: Once a critical velocity is reached, turbulent flow results and then flow does not increase proportionally with rises in pressure

True

316

How is the critical velocity leading to turbulent flow defined?

Via Reynolds number (Ng). Ng = Vdp/n [ mean velocity * tube diameter * fluid density ] / fluid viscosity

317

What are the major factors that increase Reynold's number (and therefore turbulence)

Decreased blood viscosity; increased blood velocity

318

How does lymphatic circulation differ from cardiovascular circulation?

lymphatic circulation is open, there is no pump and there is excess extracellular fluid and debris

319

__________ plays a role in blood pressure control and coagulation of blood

endothelium

320

How do endothelial cells affect blood pressure?

release angiotensin converting enzyme

321

How are the lymphatic and cardiovascular systems similar?

There is progressive branching to transport

322

What are the the main functions of the lymphatic system?

transport and homeostasis

323

Veins drain ___________ and transport to the heart

capillaries and capillary beds

324

What are the three layers of blood vessels?

tunica intima, tunica media, tunica adventitia

325

The __________ is the innermost layer of the blood vessel that contains the lumen

tunica intima

326

What is the tunica intima composed of?

simple squamous epithelium

327

What is secreted by the tunica intima?

collagen and laminin for ECM, NO for vasodilation, enzymes such as angiotensin converting enzyme (ACE)

328

True/False: The tunica intima is very metabolically active and plays a major role in homeostasis

True

329

What enters via the tunica intima?

water, electrolytes, O2, CO2

330

The ________ of the tunica intima is a cellular interface between epithelium and connective tissue made of glycoproteins and collagen

basal lamina

331

The __________ of the tunica intima is loose CT scattered with smooth muscle cells

subendothelial connective tissue

332

The _________ is a fenestrated sheet of elastin that allows diffusion of nutrients from endothelium to pass through and form gap junctions with smooth muscle cells in tunica media

internal elastic lamina

333

What is the main component of the tunica media?

Smooth muscle - allows for constriction or dilation

334

In the tunica media, the composition of elastin and collagen varies based on what?

function of the artery

335

In what vessels is the tunica media NOT found?

Not found in capillaries or post capillary venules

336

Describe structures/cells found on smaller and larger vessels in regards to the tunica media.

Smaller vessels have cells called pericytes; larger vessels have external elastic lamina

337

Where do smooth muscle cells start in the tunica media?

Start at the internal elastic lamina

338

The outermost layer of blood vessels is called ___________ and contains fibroblasts, collagen, elastic fibers that blend into the surrounding connective tissue

tunica adventitia

339

What two structures are contained on the tunica adventitia (important for blood flow)

vasa vasorum (the vessels of the vessels) and nerves (send signals to vessel to constrict or relax)

340

True/False: Nerves penetrate through all layers of the blood vessel

FALSE, only on outside, gap junctions relay info

341

When nerves in the tunica adventitia are stimulated what do they release? Describe the action

Noreepinephrine, diffuses through external elastic lamina and causes depolarization and contraction of outermost smooth muscle cells. Gap junctions propagate through layers of the tunica media.

342

When stimulated by sympathetic discharge, most blood vessels constrict. What are the exceptions?

skeletal muscle arteries dilate

343

True/False: In all elastic and muscular arteries, the vaso vasorum supplies with nutrients and O2 via diffusion

FALSE, only in small vessels, in larger vessels there are capillary beds to the tunica media

344

What are the three types of arteries?

muscular, elastic, arterioles

345

______ arteries are the biggest blood vessels and are involved in conduction of the blood from the heart.

Elastic arteries

346

The tunica media of the elastic arteries contain ______ fenestrated layers of elastin and allow vessels to stretch and _____ when alternating with smooth muscle cells which accommodates and propels the large bolus of blood from left ventricle

40-70, recoil

347

In the elastic arteries, what allows for movement and distention?

loose fibroelastic tissue in adventitia

348

Name some elastic arteries

pulmonary trunk, aorta, common carotid, subclavian, common iliacs

349

The ________ arteries are the distributing arteries and most named arteries. They include a prominent elastic lamina and external elastic lamina.

muscular

350

In muscular arteries, there are ______ layers that are connected via _____ to allow for propagation of nerve signals

4-40, gap junctions

351

What feature of muscular arteries allows neurotransmitters to pass?

clear external elastic lamina

352

The ______ are the terminal arteries where internal elastic lamina is poorly defined. There is no need for vasa vasorum in these vessels.

Arterioles

353

True/false: In arterioles, the tunica adventitia can be easily differentiated from connective tissue

FALSE - other layers can be differentiated though

354

What are the main differences between arteries and veins?

Veins are larger, arteries have a thicker tunica media, arteries maintain their round shape in sections and usually won't contain blood cells

355

______ are thin walled vessels with a single endothelial layer on a basal lamina

capillaries

356

True/False: Capillaries do not contain a tunica media or adventitia

TRUE

357

True/False Capillaries are involved in temperature control

TRUE

358

How do smooth muscle cells appear on slides?

will appear spindle shaped but on cross section will appear round

359

What are the three types of capillaries?

continuous, fenestrated, sinusoidal

360

In continuous capillaries, endothelial cells are connected via _______. These capillaries participate in ________ of amino acids and glucose

tight junctions, carrier-mediated transport

361

Where are continuous capillaries found?

nervous, muscle and connective tissue. modified in brain to limit passage of molecules.

362

In fenestrated capillaries, there are thin openings called ______ that cover pores in endothelial cell walls. These allow more leak.

diaphragm

363

Where are fenestrated capillaries found?

pancreas, intestines, and endocrine glands. Found in glomeruli of kidney but with no diaphragms.

364

In sinusoidal capillaries there is a _______ endothelial wall and basal lamina which allows several blood cells to go through at once. They also have _____ that conform to structure in which they are located.

discontinuous; irregular channels

365

Where are sinusoidal capillaries found?

spleen, liver, bone marrow, lymphoid organs

366

True/False: Veins are more numerous than arteries, larger than corresponding arteries and contain 70% more blood volume

TRUE

367

True/false: Venule walls are more permeable than capillary walls

True

368

True/false: Veins have less vasa vasorum than arteries

FALSE - have more bc blood in circulation has less O2

369

What is the preferred site for white blood cell migration?

venules (lots in lymph nodes)

370

True/false: In large veins, the tunica adventitia is more developed that that of tunica media

True - tunica media is much less prominent in veins

371

True/false: Valves are found in all veins

FALSE -found in large and medium veins

372

True/false: Smooth muscle is found in all veins

FALSE - only those above >1mm

373

The ________ is made up of endothelial cells overlying connective tissue and fibroblasts and smoooth muscle cells in the heart

endocardium

374

The endothelium in the endocardium is continuous with the tunica intima of _______

great vessels

375

The subendocardial layer of loose connective tissue in the endocardium contains what three things?

nerves, blood vessels, purkinje fibers

376

The ______ contains heart muscle that is specialized for conduction. It is also important for endocrine functions, structure, and contraction

myocardium

377

Specialized cardiac muscle cells called ______ travel superficially in the myocardium

purkinje fibers

378

Describe the pathway of electrical impulse through the heart

SA node --> AV node --> Bundle of His --> Right and Left bundle branches --> Purkinje Fibers

379

What hormone actions are secreted from the myocardium?

Hormones that control BP, fluid and electrolytes

380

Myocardial cells are attached to the _________

fibrous skeleton

381

The ________ is also the visceral layer of the pericardium. It is the innermost layer of the pericardium and the outer surface of the heard.

Epicardium

382

_______ is the passage of blood cells through intact walls of capillaries, typically accompanies inflammation

diapedesis

383

What are the two main jobs of the lymphatic system?

transport fluid away from tissues and to serve an immune function

384

Describe the flow through the lymph system?

Lymphatic capillaries --> lymphatic vessels that drain regionally --> lymph nodes where it is filtered --> lymphatic ducts

385

Describe the differences in the lymph system in comparison to the CV system.

There is a thin walled endothelial layer but there are overlapping endothelial cells without tight junctions. Discontinuous basal lamina. Numerous valves in vessels. Lumens are larger than veins. Only largest vessels have smooth muscle cells. Ill-defined boundaries between three layers. Vessels similar to vasa vasorum.

386

The subendocardial connective tissue in heart is analogus to _____

tunica intima

387

________ are places where veins and arteries come together and allow in certain circumstances bypass of the capillary bed

arterial-venous anastomoses

388

What is Bernaud's sign? What are the causes?

Bernaud's sign is when digits turn white in cold weather. Can be related to autoimmune disorders and sometimes idopathic. Typically no ischemia.

389

What is the difference between cardiac and skeletal muscle?

Cardiac muscle has branching fibers, central nuclei and intercalated discs. Do not perfectly line up.

390

During lymph node circulation, afferent lymphatic vessels pierce the lymph node and open into the _______ and penetrate the cortex.

subcapsular sinus

391

After the lymph node cortex has been penetrated, _________ continue into the medulla as branching medullary sinuses surrounded by medullary cords

Paratrabecular sinuses

392

In the medulla, subcortical sinuses are confluent with medullary sinuses and penetrate the capsule to join the ___________

efferent lymphatic vessel

393

Where are B and T cells located in the lymph nodes?

B cells are contained in the lymphatic nodules (have a germinal center) and T cells are in the deep or inner cortex

394

What cells do the medullary cords contain?

macrophages and plasma cells

395

True/False: If sentinel nodes are negative for disease, likely that other nodes are negative as well

True