Histology Of Blood Vessels

Question 1

What are the three layers of vessels?

Answer 1

Tunica adventitia, Tunica media, Tunica intima

Question 2

What layer(s) line capillaries?
Why?

Answer 2

Tunica intima only!

Need thin layer for diffusion of gas/ions

Question 3

What composes Tunica adventitia?

Answer 3

Loose CT, BVs, and nerves

Question 4

What composes tunica media?

Answer 4

Smooth muscle, elastic fibres, CT

Question 5

what composes tunica intima?

Answer 5

Endothelium, Basement membrane, CT

Endothelial cells line all vessels

Question 6

Large (elastic) Arteries
Examples
Function

Answer 6

Aorta and pulmonary arteries
High pressure vessels that convey blood from heart to systemic circulation
Designed for stretch and recoil with a media specialized with elastic fibres/elastin

Question 7

Med (muscular) Arteries
Examples
Function

Answer 7

Most arteries in the body
Distributing vessels
Have a muscular media and elastic lamellae
Media width is about equal to adventitia width
Media is specialized with smooth muscle cells and 2 elastic membranes

Question 8

Arterioles
Function
Media Specializations

Answer 8

Designed for vasodilation and vasoconstriction
Functioned for resistance against BP and to regulate BP
Media is specialized with 1-3 layers of smooth muscle cells

Question 9

Capillaries
- design

Answer 9

Wall is one endothelial cell thick for easy and rapid exchanges between blood and tissue
Peri yes wrap around endothelial cells to regulate blood flow, phagocytes and permeability of BBB

Question 10

3 types of Capillaries

Answer 10

Continuous
Fenestrated
Sinusoid

Question 11

Medium and Large Veins
Examples (of large veins)
Function

Answer 11

Examples - vena cava, femoral
Function - return blood from tissues
Have a thin walled media and a large adventitia with smooth muscle
Most of veins (have 70% of blood) and capacitance vessels

Question 12

Venules
Function
Lumen shape

Answer 12

Receive blood from capillaries
Travel with arterioles
Lumens less regular in shape than other vessels
Are capacitance vessels (volume storage)

Question 13

Vascular Enodthelium
- epithelium type
- function

Answer 13

Simple squamous epithelium
Lines all 60k miles of blood vessels
Crucial for vascular functions and homeostasis

Question 14

Atherosclerosis

Answer 14

Is a specific type of arteriosclerosis (hardening of the walls)
Follows endothelial injury/lesions to intima leading to:
1. Increased adherence of monocytes to endothelium
2. Increased permeability to LDL cholesterol
3. Increased production of reactive Oxygen species —> oxidized LDL in intima
4. In response to injury, monocytes enter intima —> differentiate into macrophages
5. Macrophages phagocytose oxidized LDL and transform into foam cells —> form the initial atherosclerotic lesion or fatty streak
6. Becomes a mature plaque as smooth muscle cells migrate from media and fibroblasts in intima form CT capsule

Question 15

Arteriosclerosis vs. Atherosclerosis

Answer 15

Arteriosclerosis is hardening of the vessel wall
Atherosclerosis is a specific type of arteriosclerosis and is narrowing of the lumen

Question 16

Lymphatic system
- Blind-end vs lymphatic vessels
- flow pattern

Answer 16

Blind-end are the smallest lymphatic vessels and form lymphatic capillaries in connective tissues that then converge into larger lymphatic vessels

Flows through lymph nodes, and contains valves for unidirectional flow

Question 17

Two largest lymphatic vessels
- drain into what?

Answer 17

Thoracic duct and right lymphatic trunk
- drain into systemic circulation (via veins)

Question 18

Function of lymphatic system

Answer 18

Remove interstitial fluid from tissues via unidirectional movement away from tissue

Absorb fat (as chyle) from the GI tract

Transport WBCs

Question 19

Primary Lymphedema

Answer 19

Congenital or presenting at birth, puberty or mid-life

Question 20

Secondary Lymphedema

Answer 20

Unintended consequence of cancer surgery and/or radiation, morbid obesity

Question 21

Primary Hypertension causes

Answer 21

Stress
Sex
Age
Endothelium - endothelial, nitric oxide
Genetics - angiotensinogen, GRA, AME, Liddle Syndrome
CNS - sympathetic activation
Cardiac - Cardiac output
Renal - Sodium retention
GI - obesity, micronutrients, alcohol
Endocrine - insulin, aldosterone

Question 22

Diabetes and Hypertension
- risk factors
- effects

Answer 22

Common risk factors:
- genetics, insulin resistance, dyslipidemia, obesity

Effects:
- atherosclerosis, endothelial dysfunction, vascular inflammation, vascular fibrosis, arterial remodelling
- cause macro and microvascular disease —> cardiovascular disease

Question 23

Causes of macrovascular disease

Answer 23

Atherosclerosis, endothelial dysfunction, vascular inflammation, vascular fibrosis, arterial remodeling

Question 24

Causes of microvascular disease

Answer 24

endothelial dysfunction, vascular inflammation, vascular fibrosis, arterial remodelling