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Flashcards in 2: Circulatory System Deck (113)
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1
Q

What are the layers of the heart from inside out?

A

endocardium, myocardium, pericardium

2
Q

What is the endocardium epithelium?

A

simple squamous

3
Q

What is the endocardium loose connective tissue?

A

fibro-elastic ct

4
Q

What other irregular tissue is in the endocardium?

A

more collagen I, elastic fibers, some smooth muscle

5
Q

What is the sub-endocardial layer of endocardium?

A

loose CT, blood vessels, nerves, most PURKINJE FIBERS

6
Q

What are purkinje fibers?

A
modified cardiac myocytes
fewer myofibrils, peripherally placed
contained stored glycogen
attached via: gap junctions & macula adherens (desmosomes)
fxn: conduct contraction impulse rapidly
7
Q

What is the myocardium of the atria like?

A

less muscle, more elastic fibers

8
Q

What is the myocardium of the ventricles like?

A

well developed muscle layer

9
Q

What is the structure of the intercalated discs of myocardium?

A

Transverse portion: “risers of stairs”; macula adherens, fascia adherens

Longitudinal portion: “step of the stairs”; LARGE GAP JUNCTIONS (ions & sarcoplasm travel through here

10
Q

What are the functions of the intercalated discs of myocardium?

A

1) attach cardiac myocytes in a row using MACULA ADHERENS
2) attach and stabilize myofibrils using FASCIA ADHERENS
3) cell to cell communication using LARGE GAP JUNCTIONS

11
Q

How does the autonomic nervous system affect the heart beat?

A

SYMPATHETICS: increase the heart rate, increase contraction force
PARASYMPATHETICS: slow the heart rate, decrease the contraction force

12
Q

What are the specialized cardiac muscle cells called that secrete hormones?

A

myoendocrine cells

13
Q

Where are the hormones secreted by the myoendocrine cells released?

A

surrounding capillaries

14
Q

What do the myoendocrine hormones function in?

A

fluid and electrolyte balance: KIDNEYS

decrease blood pressure: SMALL ARTERIES & ARTERIOLES

15
Q

What is another name for the pericardium?

A

serous pericardium

16
Q

What are the two layers of the pericardium?

A

epicardium & parietal pericardium

17
Q

What are the two layers of the epicardium?

A

sub-epicardium & mesothelium

18
Q

What is the sub-epicardium made of?

A

fibro-elastic CT (thin layer) with coronary vessels, nerves, and some adipose

19
Q

What does the mesothelium of the epicardium do?

A

secretes a serous lubricating fluid

20
Q

What is the parietal pericardium made of?

A

mesothelium: secretes serous fluid

layer of fibro-elastic CT

21
Q

What makes of the pericardial sac?

A

parietal and fiberous pericardium

22
Q

What is the pericardial cavity made of?

A

parietal and visceral pericardium

23
Q

How much fluid is held in the pericardial cavity?

A

15-50 mL

24
Q

What is the general valve histology?

A

endothelium w/ dense irregular CT (collagen 1 & elastic fibers); mostly avascular

25
Q

What is the cardiac skeleton made of ?

A

dense irregular CT

26
Q

What is are the three main components of the cardiac skeleton?

A

annuli fibrosi, trigonum fibrosum, septum membranaceum (also chordae tendinae)

27
Q

Where are the annuli fibrosum?

A

around the base of the aorta, pulmonary artery, and chamber openings

28
Q

Where are the trigonum fibrosum?

A

by aortic valve cusps

29
Q

What is the septum mebranaceum?

A

upper portion of the interventricular

30
Q

What is the function of the septum mebranaceum?

A

to produce an origin and insertion for the cardiac myocytes

31
Q

What is the general function of the cardiac skeleton?

A

isolates atrial and ventricular myocardia to ensure individual chamber contractions

32
Q

What is angina?

A

chest pain usually brought on by exhertion

33
Q

What is the cause of angina?

A

slow progressive narrowing of coronary vessels therfore less oxygen

34
Q

What is dysrythmia?

A

abnormal heart beat

35
Q

How can dysrythmia result?

A

when death or damage occurs to the purkinje fibers and other conducting tissues

36
Q

What is pericarditis?

A

often due to an infection on the pericardial cavity and therfore inflammation of the serous pericardium (visceral & parietal layers)

37
Q

What are the three major luminal wall layers in all but the smallest blood vessels?

A

tunica intima, tunica media, and tunica adventitia

38
Q

T/F: The 3 major luminal wall layers are a continuation of the hearts histological layers.

A

true

39
Q

The tunica intima is a continuation of…

A

endocardium

40
Q

The tunica media is a continuation of…

A

myocardium

41
Q

The tunica adventitia is a continuation of…

A

epicardium

42
Q

What is another name for elastic arteries?

A

conducting arteries

43
Q

What are examples of elastic arteries?

A

aorta, common iliacs, common coratids, brachiocephalics, subclavians

44
Q

What is the structure of the tunica intima of elastic arteries?

A

attenuated endothelium
thin/incomplete internal elastic lamina
thicker CT w/ elastic fibers, collagen 1, fibroblasts & smooth muscle

45
Q

What is the structure of the tunica media of elastic arteries?

A

fenestrated sheets of elastic fibers w/ some collagen 1 & smooth muscle
thin external elastic lamina possible
outer portion typically has: VASA VASORUM

46
Q

What is the vasa vasorum?

A

small BV’s supplying large BV’s

47
Q

What is the structure of the tunica adventitia of elastic arteries?

A

loose fiberelastic CT

vasa vasorum numerous

48
Q

What is the thin cellular layer covering the inside of large blood vessels?

A

endothelium

49
Q

What are muscular arteries also called?

A

distributing arteries

50
Q

What is the structure of the tunica intima of muscular arteries?

A

VERY THIN
endothelium
some CT- few smooth muscle cells possible
internal elastic lamina

51
Q

What are examples of muscular arteries?

A

brachial, radial, renal, femoral

52
Q

What layer of muscular arteries has a wavy appearance?

A

tunica intima- internal elastic lamina

53
Q

What is the structure of the tunica media of muscular arteries?

A

primarily circular smooth muscle
gap junctions btwn smooth muscle cells
elastic & reticular fibers, chondrotin sulfate
external elastic lamina possible
richly innervated w/ sypathetics –> strong contraction over a small area

54
Q

What is the thickest most dominant layer of muscular arteries?

A

tunica media

55
Q

What part of blood vessels blocks products of inflammation?

A

tunica media

56
Q

What is the structure of the tunica adventitia of muscular arteries?

A

fibroelastic CT w/ sulfated GAGs
FIBROBLASTS
vasa vasorum is present

57
Q

What is the relative size of arterioles?

A

lumen size is ~ equal to width of the vessel

58
Q

In arterioles, is the tunica intima present?

A

maybe

59
Q

In arterioles, is tunica media present?

A

no

60
Q

In arterioles, what is the tunica adventitia structure?

A

??????????

61
Q

What happens to elastic arteries as you age?

A
width increases into your 20's
# of elastic laminae increase in the tunica media
62
Q

What happens to muscular arteries as you age?

A

collagen & proteoglycans increase after middle age: decreases flexibility
coronary vessels greatly affected

63
Q

What is hypertension?

A

an increase in systolic BP, can occur ~50 yrs, due to a decrease in elastic fibers & increase in collagen 1

64
Q

What is arteriosclerosis?

A

athrosclerosis “hardening of arteries” - primarily the largest
TUNICA INTIMA: infiltrated w/ soft lipids causing decreased lumen diameter
TUNICA MEDIA: often affected - collagen 1 and sulfated GAGs can accumulate here

65
Q

What are metarterioles?

A

short terminal arteriole branches that LACK A TRUE TUNICA MEDIA
lead to capillaries and thoroughfare channels taht lead to venules

66
Q

What controls metarteriole blood flow?

A

pre-capillary sphincters: allow blood to pulse through capillaries
Found in all capillary beds

67
Q

What is an AVA?

A

arteriovenous anastamosis = AV shunt
thicker tunica media & tunica adventitia
many ANS nerves (sympathetic & parasympathetic)
FXN: control AVA lumen size & therefore the amount of blood into the capillaries

68
Q

If the AVA is closed…

A

blood to capillary bed is normal

69
Q

If the AVA is open…

A

blood by-passes capillary bed

70
Q

How is the blood flow into capillaries controlled/influenced?

A

1) metarterioles
2) AVA (some locations)
3) lumen size of terminal arteriole
4) pre-capillary sphincter

71
Q

What is the general capillary structure?

A

Cells: single layer of flattened endothelial cells
Pinocytotic vesicles: form tiny pockets through cytoplasm
FXN: mvmnt of large molecules
Cell junctions: FASCIAE OCCLUDENS-btwn endothelial cells
FXN: move macromolecules, allows cell mvmnt

72
Q

What are the types of capillaries?

A

continuous capillaries, fenestrated capillaries, sinusoidal capillaries (sinusoids)

73
Q

What are continuous capillaries?

A

most common capillary type

found in: muscle, ct, many organs

74
Q

What are pericytes?

A

considered “residual mesenchyme cells”
numerous on capillaries & venules
secrete: basement membrane & matrix components
can divide

75
Q

What can pericytes change into?

A

1) smooth muscle cells
2) endothelial cells
3) fibroblasts

76
Q

What are the functions of pericytes?

A

1) healing

2) regulate blood flow????

77
Q

Where are fenestrated capillaries found?

A

pancreas, intestines, endocrine organs, kidneys

78
Q

What is the structure of fenestrated capillaries?

A

pores with thin protein diaphragm containing 8 fibrils “wheel structure”

79
Q

What is the function of fenestrated capillaries?

A

allows greater movement of molecules and cells

80
Q

Where are sinusoidal capillaries (sinusoids) found?

A

bone marrow, liver, spleen, lymphatic organs, certain endocrine organs

81
Q

What is the structure of sinusoids?

A

enlarged diameter

many large fenestrae w/ NO PROTEIN DIAPHRAGM

82
Q

What is the function of sinusoids?

A

enhanced exchange btwn blood & tissues

83
Q

How are veins similar to arteries?

A

they have 3 tunics (intima, media, externa)

84
Q

How are veins different from arteries?

A

1) not as uniform in structure
2) often larger
3) higher number

85
Q

What are vein valves like?

A

Structure: 2 flaps of tunica intima and fibroelastic ct
FXN: 1) protection by preventing back flow
2) works with skeletal muscle to keep blood moving

86
Q

What are venules?

A

determined by tunics not diameter

87
Q

What are post capillary venules?

A

THINNEST
tunica intima: endothelium, small amount of ct & numerous pericytes
tunica media & adventitia: NONE

88
Q

What are collecting venules?

A

tunica intima: endothelium & small amounts of ct
tunica media: NONE
tunica advetitia: ct, fibroblasts, some pericytes

89
Q

What is the set up of muscular venules?

A

tunica intima: present
tunica media: NONE
tunica adventitia: CT, fibroblasts, some pericytes

90
Q

What allows products of inflammation through and loosens endothelial call junctions resulting in LEAKY VENULES?

A

incomplete tunica media

91
Q

What is the structure of small veins?

A

similar to venules EXCEPT COMPLETE TUNICA MEDIA

92
Q

what is the structure of medium veins?

A

VALVES COMMON
tunica intima: endothelium, BL, CT w/ reticular fibers, sometimes and elastic fiber network
tunica media: smooth muscle, collagen, fibroblasts
tunica adventitia: CT w/ collagen, elastic fibers, few smooth muscle cells, vasa vasorum possible

93
Q

What is usually the thickest, most dominant layer of medium veins?

A

tunica adventitia

94
Q

What is the structure of large veins?

A

tunica intima: similar to medium veins, thicker CT w/ fibroblasts & elastic fibers
tunica media: complete but thin
tunica adventitia: much fibro-elastic CT w/ vasa vasorum

95
Q

What is usually the thickest layer of large veins?

A

tunica adventitia

96
Q

How are the superficial veins of the legs different from the typical structure?

A

the tunica media is well developed

97
Q

How are the pulmonary veins different from the typical structure?

A

tunica media is well developed

tunica adventitia: some cardiac muscle close to the heart

98
Q

How is the superior vena cava different from the typical structure?

A

tunica adventitia: some cardiac muscle close to the heart

99
Q

How is the inferor vena cava different from the typical structure?

A

tunica adventitia: some cardiac muscle close to the heart is possible & longitudinal smooth muscle

100
Q

What are varicose veins?

A

enlarged and winding SUPERFICIAL veins in the legs

101
Q

What are 3 possible causes of varicose veins?

A

1) loss of skeletal muscle tone around the veins
2) degeneration of vessel wall
3) valve incompetence

102
Q

What are esophageal varices?

A

varicose veins in lower esophagus

103
Q

In what population are esophageal varices common?

A

alcoholics; caused by portal hypertension

104
Q

What are hemorrhoids?

A

varicose veins at the end of the anal canal

105
Q

What are the functions of lymphatic vessels?

A

1) drains excess interstitial fluid
2) transport lymph to lymph nodes - foreign antigen detection n lymph nodes
3) transport lymph to blood stream

106
Q

What type of capillaries to lymph capillaries resemble?

A

continuous blood capillaries

107
Q

How are lymphatic capillaries different from continuous blood capillaries?

A

1) blind ended - suddenly begin
2) NO pericytes
3) endothelial cells can overlap, create clefts btwn cells
(easy movement of materials in and out)
4) NO fenestrae & NO tight junctions btwn endothelial cells
5) has bundles of lymphatic anchoring filaments

108
Q

What does the structure of small lymphatic vessels resemble?

A

venules (a little thinner)

109
Q

What is the structure of medium and large lymphatic vessels?

A

larger lumen and thinner walls, tunics blend together more than in veins

110
Q

What are the layers of med & lrg lymphatic vessels set up like?

A

tunica intima: endothelium and thin layer of CT with elastic fibers
tunica media: thin smooth muscle layer
tunica adventitia: CT w/ collagen and elastic fibers
valves: present and closely packed

111
Q

Where do lymphatic ducts empty?

A

into the venous system at the junction of R&L internal jugular and subclavian veins

112
Q

What ducts are included in the lymphatic ducts?

A

short right lympahtic duct and the thoracic duct

113
Q

What is the general structure of lymphatic ducts?

A

tunica intima: endothelium - several layer of collagen and elastic fibers; layer of condensed elastic fibers (similar to internal elastic lamina)
tunica media: longitudinal & circular layers of smooth muscle
tunica adventitia: longitudinal smooth muscle cells; collagenous ct; vasa vasorum-like vessels