Cardiovascular Flashcards
Three layers of blood vessels
Tunica intima
- endothelial cells
- underlying CT
- (inner elastic lamina*)
Tunica media
- smooth muscle
- (elastic lamina)*
- (elastic fibers*)
- (external elastic lamina*)
Tunica adventitia
- connective tissue
- (blood vessels)
- (nerves)
( ) = maybe present
* = made by smooth muscle cells
Characteristics of the Tunica Intima
- endothelial cells
- underlying CT
- (inner elastic lamina*)
( ) = May be present
* = made by smooth muscles
Characteristics of the Tunica Media
- smooth muscle
- (elastic lamina)*
- (elastic fibers*)
- (external elastic lamina*)
( ) = maybe present
* = made by smooth muscle cells
Usually very pink, eosinophilic
Characteristics of the Tunica Adventitia
- connective tissue
- (blood vessels)
- (nerves)
( ) = maybe present
* = made by smooth muscle cells
Differences between artery and vein characteristics
Artery: thick walls that are more circular
Veins: thinner walls that are less circular
Elastic Arteries - Characteristics/Description
- large variation in size
- typically >10 mm OD
- contain fenestrated elastic lamina in tunica media
- reduce pulsatile flow
- contain blood/nerve supply
Muscular Arteries - Characteristics/Description
- large variation in size
- typically 10-40 layers of SM
- contain inner elastic lamina (IEL)
- contain external elastin lamina (EEL) when large
- reduce pulsatile flow
Small arteries - Characteristic/Description
- usually 3-10 layers of smooth muscle
- inner elastic lamina in larger ones
Comparing arteries and veins (No Question)
Arterioles - Characteristics/Describe
- “microcirculation”
- usually contain <3 layers of smooth muscle
- no elastic laminae
- most often associated with accompanying venule (V)
Capillaries - Characteristics/Describe
- “microcirculation”
- consist of endothelial cell & basal lamina
- no T. media
- no T. adventitia
- usually 4-10 μm in diameter (just enough for rbc’s to pass)
Can be continuous, fenestrated, or discontinuous
Continuous Capillaries - Location and description
Typical locations
- nervous system
- muscle
- CTs
Most capillaries in the body
Fenestrated Capillaries - Location and Description
Typical locations
- endocrine glands
- kidney glomerulus
Poors (“windows”) allow small molecules to escape
Discontinuous Capillaries - Location and Description
Typical locations
- spleen, lymph nodes
- liver
Has large gaps for RBCs, WBCs to get through
Pericytes
An important cell found with all blood vessels
- lie within capillary basal lamina
- regulate capillary permeability (e.g. blood-brain barrier)
- contractile
- help control endothelial proliferation (communicate via gap junctions)
Venules - Charactertistics/Description
- endothelial cell wall
- no T. media
- no T. adventitia
- usually 10-50μm in diameter
- leaky (most lymph & white blood cells exit here)
- histamine sensitive
Small/Medium veins - Characteristics/Description
- endothelial cell wall
- smooth muscle in T. media
- thick T. adventitia
- usually 0.1-10mm in diameter
- have valves (in extremities)
Varicose Veins
Arise when vein valves fail causing abnormal blood flow, dilation of the vein, and bulging of the skin
Large Veings - Characteristics/Description
- longitudinal bundles of smooth muscle in tunica adventitia (TA)
- tunica adventitia is much thicker than tunica media
- elastic fibers also present
eg. brachiocephalic, vena cava, etc.
Portal System
System in which blood passes through two separate beds of capillaries before returning to the heart
eg. Capillaries of the digestive tract (stomach, intestines, pancreas, spleen) and capillaries of the liver
Heart Wall - Characteritics/Description
Three layers:
- epicardium (T. adventitia)
- myocardium (T. media)
- endocardium (T. intima)
Sits within the pericardium (visceral and parietal)
Two parts of the pericardium
Visceral and Parietal
Endocardium - Characteristics/Description
Made of endothelium and CT
Myocardium - Characteristics/Description
Nuclei are in the center
Epicardium - Characteristics/Description
Lots of fat
Can have coronary artery going through it
Atherosclerosis
- Focal thickening of intima due to plaque
- Increased deposition of ECM components and lipoproteins
- Accumulation of foam cells – macrophages, SMCs heavily loaded with lipids
- Coronary arteries are predisposed (esp LAD)
- Blockage can lead to necrosis, infarcts, angina, arrhythmias
Leads to complications, such as:
- myocardial infarct (necrosis, scar tissue replacement)
- angina
- conductive anomalies (e.g. arrhythmias)
Myocardial Infarction
Heart attack
the ischemic event kills cardiomyocyes which are replaced by fibrous CT
If blood supply is lost to purkinje fibers, individual will have rythm problems
Lymphatics
Vessels look like large capillaries or small veins, but there is no blood in it
Lymphatic Circulation
Elephantiasis
Can be caused by parasitic worms, bacterial infections or persistant irritation (fine soils [red clay])
Leads to limb or other part of the body becomes grossly enlarged due to obstruction of the lymphatic vessels
Lymphatic vessels - Characteristics/Description
Look like large capillary or small vein, but there is no blood in it
Contains valves
ID
Elastic artery
ID
Muscular artery
3/5 of the thickness of the wall is made of smooth muscle
- large variation in size
- typically 10-40 layers of SM
- contain inner elastic lamina (IEL)
- contain external elastin lamina (EEL) when large
- reduce pulsatile flow
ID
Large vein
ID
Continuous capillary
ID
Fenestrated capillary
ID
Discontinuous capillary
ID
Valve (in veins)
ID
Small/Medium vein
Raynaud’s disease
vasospasm involving dermal capillary beds
This is an image typical of what type of blood vessel?
Large artery
Many layers of elastic material
Abdominal Aortic Aneurism
Due to weakening of the vessel wall (infections, inflammation, genetic (e.g Marfans, Ehlers-Danlos), elevations in MMPs, etc.
Fairly common
Deep Vein Thrombosis
DVT is a dangerous condition. Breakage of the blood clot (thrombus) leads to the formation of an embolus which travels to other parts of the body esp. lungs (pulmonary embolism) and can cause significant clinical symptoms and death.
ID and Describe
Large vein (Vena cava)
There is smooth muscle in the TA
ID
Large vein (brachiocephalic, vena cava, etc.)
- longitudinal bundles of smooth muscle in tunica adventitia (yellow)
- elastic fibers also present (black)
- note tunica adventitia is much thicker than tunica media
Elastic van Gieson stain: collagen=red; elastin=blue/black; smooth muscle=yellow)
ID
Muscular artery/corresponding vein
note circular profile of arteries vs veins
ID
Lymphedema - Caused by filariasis, microscopic thread- like worms
Venule comparison (no question
These are part of the microcirculation, ranging from about 10 – 100 um (postcapillary venules) up to 1 – 2 mm (smallest veins). Very porous and play an important role in inflammation
ID
Arteriole (top) *note orientation of nuclei of endothelial and smooth muscle cells
- “microcirculation”
- usually contain 1-3 layers of smooth muscle
- elastic laminae absent
- most often associated with accompanying venule (V)
ID
Arteriole (left) *note orientation of nuclei of endothelial and smooth muscle cells
- “microcirculation”
- usually contain 1-3 layers of smooth muscle
- elastic laminae absent
- most often associated with accompanying venule (V)
ID
Arteriole (left) and venule (right) with skeletal muscle in the top right corner
ID
a = endothelial cell nucleus
b = smooth muscle nucleus
c = fibroblast nucleus
d = inner elastic lamella
e = adventitia
