Blood vessel questions Flashcards
Describe the difference btwn the epicardium and the endocardium
Epi- surface of heart– mesothelium and subepicardial layer of loose connective tissue
Endo- lines atria and ventricles— endothelium and sub endothelial layer of CT
What is the physiological significance of the number of elastic lamina in the aorta?
40-70 layers of fenestrated elastic lamellae
-withstand the constant pressure
How can you distinguish an elastic artery from a mixed artery?
Elastic media– thick in elastic
Tunica media and adventitia approx. the same thickness in mixed
What is the function of the fenestrae in the elastic lamina of the aorta?
allow the aorta to be more flexible
Describe what happens to the external elastic lamina as arterial vessels become smaller along the vascular tree
Gets smaller & smaller until it is no longer present in small vessels- arterioles
What is the medical importance of foam cells?
fat-laden macrophages seen in atherosclorosis
-indication of plaque buildup
Tunica intima
Internal elastic lamina
forms permeable/semipermeable barrier
Tunica media
smooth muscle
Variable amounts of elastic fibers and lamellae/reticular fibers/proteoglycans
Larger vessels have
- EEL
- Pericytes
controls diameter and blood pressure and movement
Tunica adventitia
outermost layer
fibroblasts and longitudinally oriented type I collagen and elastic fibers
Larger blood vessels- vasa vasorum
Provides support
attaches vessels to tissue
carries vessels and nerves
Internal elastic lamina
Borders the media
fenestrated layer of elastin
External elastic lamina
borders media of larger vessels on superficial portion
Vasa vasorum
provides nutrients to the vessel
Elastic artery
Aorta and main branches
intima- endothelial cells contain Weibel-Palade bodies
—store and release substances important for homeostasis and inflammation
Media- 40-70 layers fo fenestrated elastic lamellae
Adventitia- thin
Mixed, músculo-elastic arteries
Part of terminal abdominal aorta/ iliac arteries/ external carotids/axillary arteries
Has more internal elastic membrane
Transitional segment btwn large and medium arteries
Medium, muscular, distributing arteries
Most arteries are this type
innervated by ANS– regulates blood flow
Intima- thin– prominent IEL
Media- thick– EEL
Adventitia- may be as thick as media
–vasa vasorum and lymphatics are poorly developed
Arterioles
Maintain normal BP in arterial system
reduce BP entering capillaries
Intima- thin IEL is absent in small ones
Media- 1-5 layers
Adventitia- moderate to scant
Metarteriole/precapillary sphincter
Regulates blood flow into capillaries
List the three main types of capillaries. Give an example of an organ in which each type is found
Continuous- muscle/nervous tissue
fenestrated- Pancreas/intestines
Sinusoids- endocrine glands/liver/spleen
What morphological features allow you to distinguish an artery from a vein?
More variation in size and structure larger caliber, more numerous More vasa vasorum More collagen and less elastic and smooth muscle Thick adventitia Valves
What is the difference btwn a portal system and an arteriovenous anastomosis?
Portal- one cap-another
arteriovenous- arterioles- venules bypass cap
What features of lymphatic capillary structure are important for their physiological function?
Large lumen/thin walls/discontinuous or absent basal lamina
Weibel-Palade body
Membrane-bound inclusion
store and releases substances that help homeostasis and inflammation
Large vein
SM in long. bundles
Intima- continuous endothelium and basal lamina
-no IEL
Media- incomplete/absent
Adventitia- large
-well developed vasa vasorum and lymphatics
SVC/IVC
portal vein
Venule
Two classes
- Pericytic- post capillary venules
- Muscular- receive blood from the pericytic venues and accompany arterioles
Thick adventitia
Exchange of material that was started in capillary
Become leaky in response to histamine and serotonin
Pericytes
Satellite cells
- surround capillaries and some post-capillary venues
- some capable of contraction- regulate blood flow
Can serve as- stem cells for endothelial and smooth muscle cells after injury
the structure with the most distinctive internal elastic lamina is the
muscular artery
The structure likely to contain the greatest density of vasa vasorum in its tunica adventitia is the
Vein
The structure with the most elastin in its tunica media is the
Aorta
The structure allowing the most exchange of nutrients with the surrounding tissues is the
blood capillary
the structure most likely to contain longitudinal smooth muscle in its tunica adventitia is the
large vein
