(4) Heart and Vascular System (Dennis)

Question 1

What type of muscle is this?

Describe

Striated or non-striated?

Voluntary or involuntary?

Answer 1

Skeletal Muscle

Striated & Voluntary

Question 2

What type of muscle is this?

Describe

Striated or non-striated?

Voluntary or involuntary?

Answer 2

Cardiac Muscle

Striated

Involuntary

Question 3

What type of muscle is this?

Describe

Striated or non-striated?

Voluntary or involuntary?

Answer 3

Smooth Muscle

Non-striated

Involuntary

Question 4

What type of muscle is this?

How is it organized?

Answer 4

Smooth Muscle

Occurs as bundles or sheets of elongated fusiform cells

No visible striations

Interconnected by gap junctions

Question 5

Describe smooth muscle contraction

Answer 5

Tension transmitted via densities to the membrane

Cells contract as one unit and assume a globular shape

***Anchor to cytoplasmitc densities/dense bodies

Question 6

What is this muscle type?

Answer 6

Cardiac muscle

Question 7

What are 2 distinguishing features of this type of muscle?

Answer 7

Cardiac Muscle

Intercalated discs

Purkinje cells

Question 8

What are intercalated discs?

Answer 8

Transverse junctions at the ends of cells that allow passage of electrical current

Question 9

What are purkinje cells?

Answer 9

Modified cardiac muscle cells that act as the ‘pacemaker’ for the heart

Question 10

What is the fibrous pericardium?

Answer 10

Outer covering of dense connective tissue

Question 11

What are the three components of the serous pericardium?

Answer 11

Parietal layer of Serous Pericardium

Visceral layer of serous pericardium

Pericardial cavity

Question 12

Label the

Endocardium

Myocardium

Epicardium

Answer 12

Question 13

Label the

Endocardium

Myocardium

Epicardium

Answer 13

Question 14

What is this revealing?

What type of CT?

Answer 14

Epicardium

Dense fibrocollagenous CT with elastic fibers, lined with mesothelium

*Outermost layer of the heart wall

Question 15

What is the notable structure of this tissue sample?

Answer 15

Branches of coronary arteries are embedded in adipose tissue of the

EPICARDIUM

Question 16

What is the myocardium characterized by?

Answer 16

Striations

Intercalated discs

Dyad T-tubule system

Mitochondria

Lipofuscin granules

Atrial granules

Question 17

What are the arrows pointing at?

Answer 17

Intercalated discs

*Specialized, interdigitating junctions b/w cardiomyocytes

Question 18

Where are intercalated discs found?

Answer 18

At sites where cells meet end-to-end

ALWAYS COINCIDE WITH Z-LINES

Question 19

Function of intercalated discs?

Answer 19

Binds cells

Transmit forces of contraction

Allow spread of excitation

Question 20

Interdigitating junctions have 3 different types of membrane-to-membrane contacts:

What are they?

Answer 20

Transverse Region (Perpendicular)

1. Fascia Adherens
2. Desmosomes

Longitudinal region (parallel)

3. Gap Region

Question 21

Function of

Fascia adherens

Answer 21

Actin filaments at the ends of terminal sarcomeres insert into junction

• Transmit contractile forces b/w cells
• Most predominant

Question 22

Function of

Desmosomes?

Answer 22

Provide anchorage for the

intermediate filaments of the cytoskeleton

Question 23

Function of

Gap (nexus) junctions

Answer 23

Sites of low electrical resistance

Allows excitation to pass b/w cells

Question 24

What is a dyad made of?

Answer 24

1 T-Tubule + 1 SR cisterna

Question 25

What are these structures called?

Answer 25

Dyad T-tubules

Question 26

Where are **dyad T-tubules** found?

Answer 26

Found at Z-lines Permits uniform contraction of myofibrils within a single cardiomyocyte

Question 27

What is this image revealing?

Answer 27

Lipofuscin Granules

Question 28

What are **lipofuscin granules?**

Answer 28

- Small bodies that accumulate with age in stable non-dividing cells (i.e. cardiomyocytes) - Contain material derived from residul bodies after lysosomal digestion

Question 29

What are **myoendocrine cells?**

Answer 29

Atrial cardiomyocytes that contain **membrane-bound granules** Contain precursor of **atrial natriuretic factor (ANF)**

Question 30

Atrial Natriuretic Factor (ANF) targets _______ to _______ Na+ and H2O retention

Answer 30

Atrial Natriuretic Factor (ANF) targets **kidneys** to **decrease** Na+ and H2O retention

Question 31

Ventricular endocardium has a \_\_\_\_\_\_\_\_\_\_\_\_\_\_

Answer 31

Subendocardial layer

Question 32

How do you distinguish b/w ventricular vs atrial endocardium?

Answer 32

In atria, purkinje fibers are often closer to the endothelium and intermixed with the myocardium

Question 33

What are **nodal cardiomyocytes?**

Answer 33

Modified cells w/in SA/AV nodes that initiate/relay electrical signals

Question 34

What is the order of the conduction system?

Answer 34

SA node --\> AV node --\> AV bundle --\> R/L bundle branches --\> Purkinje fibers

Question 35

What is this?

Answer 35

Cardiac Skeleton

Question 36

What is this?

Answer 36

Heart valve