Cardiovascular

Question 1

Cardio system components

Answer 1

• Heart
• Vessels
• Blood

Question 2

Vessel components

Answer 2

• Arteries
• Capillaries
• Veins
• Lymphatics

Question 3

Functions

Answer 3

• Blood supply and delivery
• Waste removal
• Communication via endocrine
• Inflammation
• Thermoregulation

Question 4

Can you tell veins from arteries histologically?

Answer 4

Yes! Arteries have thicker walls due to higher blood pressure and smooth muscle linings

Question 5

Circulation in most mammals

Answer 5

2 circuits: (interconnected)

• Pulmonary
• Systemic
• Flow in response to pressure gradients*

Question 6

Heart functions

Answer 6

• Muscular pump (cardiac muscle)

- Autonomic nervous stimulation

Question 7

ECG

Answer 7

Tells you about degree of polarization/depolarization, not about strength or contractility

Question 8

3 layers of the cardiac system (heart, veins, arteries)

Answer 8

• Epicardium
• Myocardium
• Endocardium

Question 9

Epicardium

Answer 9

Serosal (outer) layer
- Simple squamous epithelium with a CT base
Visceral layer: sits against the outer surface of the heart
Parietal layer: attaches to the pleura

Question 10

Myocardium

Answer 10

Made of cardiac muscle

Question 11

Endocardium

Answer 11

Thin wall

• -> stops blood from clotting in circulation
• -> when damaged, underlying CT is exposed and activates clotting factors

Question 12

Valves

Answer 12

• AV
• Pulmonic
• Aortic

Question 13

Which valve of the heart is bicuspid?

Answer 13

Left AV valve

Question 14

Arteries

Answer 14

• high pressure! what gives you a pulse*
• –> multiple rings of connective tissue and smooth muscle
• large (elastic): aorta
• medium (muscular): smooth muscle
• Small: arterioles

Question 15

Aorta

Answer 15

Stretchable and shrinks back to normal size without expending energy
–> maintains bp in larger arteries

Question 16

What has active control over blood pressure?

Answer 16

Smooth muscle

Question 17

Artery layers

Answer 17

• Intima: endothelium, simple squamous, prevents clotting
• Media: smooth muscle, CT (loose areolar), elastic
• Adventitia: outer layer CT, holds arteries in place, vasa vasorum

Question 18

Vasa Vasorum

Answer 18

Found in large arteries

• Blood vessel that nourishes the big vessels
• is microscopic (hard to see histologically)

Question 19

______ is continuous with connective tissue on the outside of the muscle

Answer 19

Adventitia

Question 20

Capillaries

Answer 20

Smallest diameter vessels

• only fit 1 RBC at a time (7-10 microns wide)
• O2 and metabolic exchange

Question 21

Types of capillaries

Answer 21

• Continuous: endothelium, little CT, tight junctions
• Fenestrated: endocrine glands and GIT, absorption (endothelial cells thin out = holey)
• Discontinuous: sinusoidal (liver, spleen, marrow)

Question 22

Veins/venules

Answer 22

Low pressure

• Same tunics, not as distinct
• Valves

Question 23

Vein tunics

Answer 23

• Minimal tunica media

- Adventitia usually largest, collagen, elastin

Question 24

Venules

Answer 24

• Post capillary (leaky)

- Muscular (more media)

Question 25

Varicose veins

Answer 25

Veins get enlarged and valves become incompetent = venous blood pooling

Question 26

Lymphatics and Microcirculation

Answer 26

• Blind ended tubes
• Return tissue fluid to blood stream
• Capillaries are more permeable
• Thoracic duct

Question 27

What are capillaries permeable to?

Answer 27

• Fluid
• Protein
• Cells

Question 28

Can you distinguish lymphatics from veins?

Answer 28

Histologically, no.

• veins have RBCs, not lymphatics
• trauma that allows blood into lymphatics could cause similarities