Cardiovascular Flashcards
What is the function of arteries and veins?
arteries: convey blood from heart to tissues of the body.
veins: return blood from the tissues back to the heart
How are lymphatic vessels are associated with CVS?
drain excess fluid from tissue and return it to the CVS
-run one-way from the tissues to the veins.
What components make up the tunica intima. What type of epithelium tissue and where is it present?
-endothelium-simple squamous epithelium.
present in all blood vessels, lymphatic vessels, and heart cavities.
-basal lamina of all endothelial cells.
-subendothelial layer: areolar CT and smooth muscle.
1.) internal elastic membrane- a network of elastic fiber bands.
Tunica media
composition variable (dependent upon vessel)- predominantly elastic membranes or circularly arranged smooth muscle depending on type of vessel, or mixture of both.
Tunica adventitia
- usually longitudinally arranged collagenous tissue.
- large arteries and veins, contains blood vessels (vasa vasorum and nervi vasorum)
microvasculature
consists of arterioles, cappillaries (area of exchange), emerging benules and arteriovenous anastomoses (AV shunts)
what do Av shunts do? Where is it found?
contraction allows BF to capillary beds;relaxation causes less BF to capillary beds
-found in skin of finger tips, lips, nose, erectile tissue
What is the function of AV shunt? where is its exception in this role?
thermoregulation
exception in erectile tissue
Sympathetic Innervation
NE causes vasoconstriction in skin and vasodilation in arterioles in skeletal muscle
Vasovagal syncope
emotional fainting (not always), can occur in urination, defecating. -arteries dilate (acute drop in BP), vagus nerve (parasympathetic) is stimulated causing bradycardia- person faints.
postcapillary venule
endothelial cells respond to histamine (dilate) and serotonin (constrict).
- no tunica media, little smooth muscle.
- pericytes, basal lamina
Muscular Venules
- endothelial cells
- basal lamina
- 1-2 layers of smooth muscle found in the T. media
how are veins different than arteries?
walls are thinner, lumen is larger, internal and external elastic membranes are small and attenuated or absent.
What is the function of arteriole?
major regulator of blood flow and peripheral resistance; control amount of blood that enters the capillaries
Where are continuous capillaries found and describe is morphology.
found in lung, muscle, and CNS
- complete endothelial cells (no pores)
- many pinocytotic vesicles
- continuos basal lamina
- tight junctions is not complete-some leak (except CNS)
- pericytes
Where are fenestrated capillaries found and describe is morphology.
found in endocrine glands, gi tract, glomeruli
- endothelial cells with POREs (80-100nm)
- diaphragm spans pores
- continuous basal lamina
- pericytes
Where are discontinuous capillaries found and describe is morphology.
found in liver, spleen, bone marrow
- large gaps present (NO DIAPHRAGMs)
- incomplete or missing BASAL Lamina
- important so that RBCs can leave when needed.
What are the 6 function of capillaries besides exchange in gases, glucose, aa, electrolytes.
In the endothelial cells
- site of angiotensin 2 conversion
- produce growth factors (EDGF)- proliferation of new blood vessels
- inactive molecules
- release nitric oxide, aka endothelial relaxing factors- causes vasodilation
- anti-thrombogenic function: produces anticoagulants and vasodilators
- serve as a barrier between blood and sub-endothelial tissue, protective mechanisms such as thrombus formation can occur here
what type of molecules can endothelial cells in capillaries inactivate and what effect does it have on the blood vessels?
Norepinephrine, serotonin (mostly vasoconstrict)
Prostaglandins (mostly visodilator)
Postcapillary venule responds to what molecules?
histamine and serotonin
What is the morphological difference between postcapillary venule and muscular venule?
- muscular venules have 1-2 layers of smooth muscle in tunica media while postcapillary venule does not.
- postcapillary venule has pericytes.
Describe the morphology of continuous capillaries and where in the body could it be found?
- complete endothelial cells with no pores
- many pinocytotic vesicles
- continuous basal lamina
- tight junctions isn’t complete-some leak (except CNS)
- pericytes
- found in muscle, lungs and CNS
Describe the morphology of fenestrated capillaries and where in the body could it be found?
- endothelial cells with pores
- diaphragm spans pores
- continuous basal lamina
- pericytes
- found in endocrine glands, GI, glomeruli (specialization don’t have diaphragm)
Describe the morphology of discontinuous capillaries and where in the body could it be found?
large gaps present (NO DIAPHRAGMS)
-incomplete or missing basal lamina
-found in liver, spleen, bone marrow;
a way for blood can pull and leave easily.
