Cardiovascular System I

Question 1

What is the outer layer of the heart made of?

Answer 1

Epicardium

simple squamous epithelium

subepicardial connective tissue containing:

blood vessels, fat, nervous tissue

Question 2

What is the myocardium? What is it comprised of?

Answer 2

Middle layer of the heart

muscle cells and capillaries

Question 3

Where is the endocardium? What is it?

Answer 3

Inner layer of the heart

squamous epithelium/endothelial layer, subendocardial CT, conducting tissue

Question 4

Answer 4

Question 5

What cell type is this?

Answer 5

Cadiac muscle

small cells

central nuclei

branching, long fibres joined end-to-end

intercalated discs

Question 6

ID is

Answer 6

intercalated disc

anchors actin filaments of sarcomeres to neighbouring sarcomeres via fascia adherens (desmosomes)

gap juctions run in the perpendicular join between IDs

Question 7

Answer 7

Purkinje fibres

larger than muscle cells

limited non-functional myofibrils (tf light pink H&E)

full of glycogen

in subendocardium (beneath endocardium lining the lumen of the heart)

Question 8

The intima of blood vessels is lined with

Answer 8

simple sqamous epitheliym (e.g. the endothelium) on a basal lamina supported by a thin subendothelial CT layer

Question 9

The connective tissue of the media is secreted by the _________________ and contains?

Answer 9

Smooth muscle

collagen III, elastin, and ground substance

Question 10

What comprises the connective tissue of the adventitia?

Answer 10

Collagen I, elastin, ground substance

plus embedded fibroblasts

Question 11

What is the vasa vasorum?

Answer 11

Blood vessels that supply larger blood vessels with nutrients and oxygen

Question 12

What type of arteries are the aorta and the carotids?

Answer 12

Elastic

~50 layers of elastin between the smooth muscle cells

Question 13

What does diastolic pressure reflect?

Answer 13

Elastic recoil of the arteries near the heart transferring energy into blood to push it through arteries

Question 14

What is the main role of muscular arteries?

Answer 14

Regulating pressure

Question 15

Answer 15

Question 16

What is the diameter of an arteriole?

Answer 16

<0.1mm

Question 17

Where is the greatest resistance to flow?

Answer 17

Arterioles

Question 18

What are the primary regualtory vessels of blood pressure?

Answer 18

arterioles

Question 19

What is the metarteriole?

Answer 19

the metarteriole is between the arteriole and the capillary bed

single muscle cells act as sphincters to control capillary flow

Question 20

What are the structural features of the capillary?

Answer 20

• single endothelial cell rolled into a tube
• sealed with a tight junction
• basal lamina, barrier to diffusion (dense layer of CT)
• no media; some pericytes
• few collagen fibres (adventitia merged to ground substance of extracellular space)

Question 21

What percentage of blood is in the veins?

Answer 21

70%

Question 22

70% of blood is in the

Answer 22

veins

Question 23

How does venous structure differ from arteries?

Answer 23

• thinner media
• thicker adventitia (to withstand hydrostatic pressure)
• one-way valves

Question 24

What are the characteristics of venules?

Answer 24

• first level of venous collection
• media initially pericytes, eventually smooth muscle
• preferred site of diapedesis
• affected by histamine, cytokines
• look similar to arterioles but larger diamater due to lower P (must carry same volume)

Question 25

Relative to arteries, medium to large veins have:

Answer 25

• more subendothelial CT than arteries
• thicker adventitia (+CT), thinner media (-muscle)
• longitudinal SM in adventitia to prevent buldging
• larger diameter

Question 26

Lymphatic vessels drain

Answer 26

plasma/fluid leaked out from capillaries and venules into the extracellular space

Question 27

What is the =difference between a lymphatic vessel and a vein or capillary?

Answer 27

No gap junction between ends of the endothelial cell tf leaky so plasma and fluid can get in

No RBCs in lumen

thinL no media/muscle! just CT and endo