Cardiac Histology Flashcards Preview

CPR Midterm > Cardiac Histology > Flashcards

Flashcards in Cardiac Histology Deck (34)
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1

Hallmarks of smooth muscle

no visible striations
elongated nuclei w/ rounded edges
diffuse staining
typically not wavy

2

Smooth muscle cells & # of nuclei

elongated fusiform cells with 1 nucleus

3

What connects smooth muscle cells?

gap junctions

4

Innervation of smooth muscle

inherent rhythmic contraction that is also responsive to ANS to increase or decrease contractile force

5

How is dense regular CT different from smooth muscle?

more wavy bundles of collagen that align in direction of stress (cells follow waves of collagen bundles)

6

Describe smooth muscle contraction

thin & thick filaments that anchor to dense bodies which connect to cell membrane

caveolae receive tension from dense bodies & allow for Ca2+ in to initiate contraction

**cells contract as 1 unit & assume globular shape

7

What are dense bodies composed of?

desmin & vimentin intermediate filaments

8

Hallmarks of cardiac muscle

striations, intercalated discs
cells w/ varying diameter & centrally located nuclei
lipofuscin granules
LOTS of capillaries

9

Cardiac muscle cells & # of nuclei

short, branched, Y-shaped w/ 1-2 nuclei

10

Intercalated discs

transverse junctions @ ends of cardiocytes that allow passage of electrical current (parallel to length of cell)

11

Purkinje cells

modified cardiac muscle cells that act as "pacemaker" for heart

12

What composes the pericardium?

Fibrous pericardium (dense CT)

Serous pericardium (parietal & visceral layers)

13

What is the visceral layer of the pericardium also called?

epicardium (outer layer of heart wall)

14

Anatomy of the heart wall

epicardium (mesothelium + CT)
myocardium (cardiac muscle)
endocardium (CT + mesothelium)

15

Epicardium histo features

dense fibrocollagenous CT w/ elastic fibers (lined by mesothelium)
branches of coronary arteries in fat/adipose tissue

16

Myocardium histo features

striations/intercalated discs/lipofuscin granules

diad T tubule system

Atrial granules

LOTS of mitochondria

17

Cells of myocardium

cardiocytes (contractile)
nodal cardiocytes (SA & AV node)
myoendocrine cardiocytes (hormonal peptide)

18

What are the roles of intercalated discs & where do you find them?

bind cells, transmit forces of contraction & allow spread of excitation

found where cells meet end to end (align w/ Z lines)

19

3 types of IC discs (memb to memb contact)

Fascia Adherens (actin @ end of sarcomeres)
Desmosomes (anchor for intermed filaments)
Gap jxns

20

What is purpose of gap junctions?

parallel membrane connections that allow excitation to pass b/w cells

sites of LOW electrical resistance

21

What is purpose of fascia adherens?

transverse membrane connections that transmit contractile forces b/w cells

22

Role of diad T-tubules

permits uniform contraction of myofibrils w/ in 1 cardiocyte (found @ Z lines)

1 tutubule & 1 SR cisterna

23

Describe the conducting system of the heart

SA node --> AV node --> AV bundle --> R/L bundle branches (down intervent septum) --> Purinje fibers

24

Role of parasympathetic & sympathetic fibers in nodes

MODIFY rate of intrinsic cardiac muscle contraciton

25

Nodal cardiocytes

modified cells in SA/AV nodes that start & relay electrical signals

26

Purkinje fibers

specialized cardiac muscle cells that conduct electrical impulse for coordinated contraction

@ periphery of myocardium w/ fewer myofibrils and striations

27

Major features of myocardium

Cardiocytes
Intercalated discs
Diad (T-tubule system)
Granules

28

Myoendocrine cardiocytes (atrial cells)

have membrane-bound granules that secrete atrial natriuertic factor (ANF targets kidneys to decrease H20 retention)

29

Endocardium in ventricles

has subendocardial layer (CT w/ smooth muscle)

branches of Purkinje fibers

merges w/ myocardium

30

Endocardium in atria

NO subendocardial layer

Purkinje fibers closer to endothelium

intermixed w/ myocardium