Cardiovascular System Histology

Question 1

What is microcirculation?

Answer 1

Capillaries exchanging nutrients

Question 2

What can regulate blood flow through capillary beds?

Answer 2

Precapillary sphincters

Question 3

Difference in tunicas between arteries and veins

Answer 3

Arteries have more smooth muscle and elastic fibers. Veins have thicker adventitia and tend to be larger than arteries
-veins tend to be softer; arteries tend to be stiffer

Question 4

What surrounds capillaries?

Answer 4

Pericytes

Question 5

1. Blood vessels and nerves supplying the heart course through what layer?
2. Electrical conducting system course along which layer?

Answer 5

1. Epicardium

2. Endocardium

Question 6

Function of intercalated discs?
Which part of the heart lacks these disks?
Why?

Answer 6

Separate cardiac muscle cells
Electrical conducting system
To aid in the spread of electrical current (gap junctions also help spread this current)

Question 7

Similarity between skeletal and cardiac muscle?

Difference?

Answer 7

They are both designed for sudden large contractions

Cells are not fused in cardiac muscle (they have intercalated discs and gap junctions)

Question 8

Cardiac muscle primarily uses what for energy? What else can they use?

Answer 8

Primarily metabolize fatty acids but can also use glycogen

Question 9

MI is detectable by what lab test and when is this elevated?

Answer 9

Troponin levels in blood (elevated from 3 hours-2weeks after MI)

Question 10

When cardiac muscle is damaged, what does it generally get replaced by

Answer 10

Connective tissue

Question 11

Myocardium is thickest and thinnest where?

Answer 11

Thinner in atria, thickest in left ventricle (because it pumps blood to systemic circulation)

Question 12

What are valves made of?

Answer 12

DCT and LCT and elastic fibers

Question 13

Which heart layer contains blood vessels?

Answer 13

Epicardium

Question 14

Where does chest pain come from?

Answer 14

Pain fibers in the heart itself (there are sensory fibers in the heart)

Question 15

Sympathetic control of the heart comes from what spinal levels

Parasympathetic?

Answer 15

T1-T4

Vagus nerve

Question 16

Sympathetic: what neurotransmitter does preganglionic neuron use? Post ganglionic?

Parasympathetic: what neurotransmitter does preganglionic neuron use? Post ganglionic?

Answer 16

Sympathetic: pre= acetylcholine; post= norepinephrine

Para: pre and post= acetylcholine

Question 17

Sympathetic innervation of coronary arteries causes?

Parasympathetic?

Answer 17

Dilation

Constriction

Question 18

Sympathetic innervation of the heart uses which receptor?

Parasympathetic?

Answer 18

B-adrenergic (Gs coupled)

Muscarinic (Gi coupled)

Question 19

Epinephrine and norepinephrine has similar actions on the heart as

Answer 19

Sympathetic innervation

Question 20

Large arteries are also considered __ arteries. Why?

Answer 20

Elastic; allow for distension and recoil in response to ventricular contraction

Question 21

Medium arteries are also called __ arteries. Why?

Answer 21

Muscular; thick tunica media (smooth muscle)

Question 22

Key feature of arterioles

Answer 22

Thin tunica media

Question 23

LARGE ARTERIES
2 components of tunica intima?
Components of tunica media?
Components of tunica adventitia?

Answer 23

Endothelium and basal lamina
Many layers of smooth muscle and a lot of elastic fibers
Connective tissue containing blood vessels, nerves, fibroblasts, and macrophages

Question 24

MEDIUM ARTERIES
Components of tunica intima?
Components of tunica media?
Components of tunica adventitia?

Answer 24

Same as large arteries
Many layers of smooth muscle, little elastic fibers
Same as large arteries

Question 25

ARTERIOLES
Components of tunica intima?
Tunica media?
Tunica adventitia?

Answer 25

Same as previous 2
Fewest layers of smooth muscle (so cannot contract much)
Typical components but this connective tissue is often continuous with connective tissue to surrounding tissue

Question 26

How does sympathetic innervation of arteries vasoconstrict?

Answer 26

Via NE activation of alpha-1 adrenergic receptors (Gq-coupled)

Question 27

Parasympathetics typically do not innervate arteries except?

So because of this you would say that vasoconstriction happens because of? And vasodilation happens because of?

Answer 27

Arteries in abdominal viscera vasodilate via muscarinic receptors

Vasoconstriction-sympathetic innervation; vasodilation- termination of sympathetic innervation

Question 28

Function of pericytes?

Answer 28

Surround capillaries; have some contractile function but work mostly as filters

Question 29

What can pass through fenestrated capillaries?

Answer 29

(Has pores); lipids and other hydrophobic molecules (or else it needs a carrier)

Question 30

How do immune cells get into CNS?

Answer 30

They cannot; CNS is immune privileged so they cannot unless brain cells enter BBB to allow entry

Question 31

Function of precapillary sphincters?

Answer 31

Can constrict and reduce blood flow into capillaries

Question 32

What are shunts?

When shunt is open, what happens?
When would shunt be open

Answer 32

Direct connections between an arteriole and venule that can be constricted

Less blood flow to capillaries (because it is going through shunt instead)
Would be open when you want to preserve heat

Question 33

What would failure to form a capillary bed cause?

Answer 33

Arteries would get tangled with veins and then the tissue would never be able to get O2, so tissue would eventually die

Question 34

What is diapedesis?

Answer 34

Migration of blood cells across endothelium.

Question 35

Function of neutrophils on endothelial cells?

Answer 35

They can bind to receptors to trigger opening of gaps that will allow them to pass through endothelium

Question 36

Comparing veins to arteries:

1. Muscular venules have similar structure to?
2. Large veins?
3. Components of medium veins?

Answer 36

1. Arterioles
2. Muscular arteries
3. Endothelium, thin tunica media and tunica adventitia

Question 37

Does regulating BP have more to do with arteries or veins? Why?

Answer 37

Arteries because of the smooth muscle