PSL301: Cardio 7 Flashcards
List the chemicals that cause vasoconstriction
- NE binding to a-receptors
- ANG II
List the chemicals that cause vasodilation
- E binding to B2-receptors
- Adenosine
- Natriuretic peptides
- low O, high CO2, high H+, high K+
Physiological role of NE (a-receptor)
Baroreflex
Physiological role of ANG II
Increase blood pressure
Physiological role of E (B2-receptor)
Increased blood flow / dilation
Physiological role of adenosine
Increase blood flow to match metabolism
Physiological role of natriuretic peptides
Reduce blood pressure
Physiological role of low O2, high CO2, high H+, high K+
Increase blood flow to match metabolism
NE is a type of…
NT
ANG II is a type of…
Hormone
E is a type of…
NT
Adenosine is a type of…
Paracrine signal
Low O2, high CO2, high H+, High K+ is a type of…
Paracine signal
Natriuretic peptides are types of…
Hormones
NT
Source of NE
sympathetic neurons
Source of ANG II
Plasma hormone ANG I
Source of E
Adrenal medulla
Source of adenosine
hypoxic cells
Source of low O2, high CO2, high H+, high K+
Cell metabolism
Source of natriuretic peptides
Atrial myocardium
Brain
The difference of effects for E and NE depend on…
the receptor
Define: hyperemia
Locally mediated increase in blood flow
What happens during active hyperemia?
- Release of (metabolic) vasodilators into ECF
- Arterioles dilate
- Decrease resistance & increase blood flow
- More supplies given to the metabolically active cell
- Blood flow eventually washes vasodilators away
2 types of hyperemia
- Active
2. Reactive
What happens during reactive hyperemia?
- Cells release metabolic vasodilators into ECF
- There is an something blocking the blood vessel going to that tissue
- Arterioles will dilate until occlusion is removed
- Decreased resistance & increased blood flow
- Blood will carry the vasodilators away over time
Which are metabolic vasodilators?
- Adenosine
- Low O2
- High CO2
- High H+
NE binding to a-receptors cause vasodilation/vasoconstriction?
Vasoconstriction
Capillary density is related to…
metabolic activity of cells
Bone marrow, liver, spleen do not have capillaries. Instead, they have…
sinusoids
Sinusoids
Capillary-like vessels at the bone marrow, liver, and spleen. Large gaps that allow proteins and RBC to move across.
How many capillaries are there?
> 10 billion
SA of capillaries?
500 - 700 m2
2 types of capillaries
- Continuous
2. Fenestrated
What are the gaps between continuous capillaries? Fenestrated ones?
- Leaky junctions / endothelial cell junctions
- Endothelial cell junctions & fenestrations
Difference b/t continuous and fenestrated capillaries?
Continuous:
- inner lining smooth
- endothelial cell junctions only
- only solutes can pass through
Fenestrated:
- rough inner lining
- also have fenestrations
- allow high volumes to flow through
Where can continuous capillaries be found?
muscles
neural tissues
connective tissues
Where can fenestrated capillaries be found?
kidneys
intestines
Relationship between total x-section area and velocity of flow
Higher area = lower velocity of flow
Exchange between plasma & ISF occurs by ___ pathway or ___ transport
paracellular
endothelial
Small dissolved solutes and gasses move by __
diffusion (go through cell without a vesicle)
Large solutes & proteins move by ___
vesicular transport
Paracellular pathway
Substance passes through space between endothelial cells
Endothelial transport
Substance passes through an endothelial layer by going through endothelial cells
At capillaries, large proteins are transported by…
transcytosis
Define: bulk flow
Mass movement of fluid as a result of hydrostatic or osmotic pressure gradients
Filtration occurs at __ end; absorption occurs at __ end
Arteriole
Venous
Define: filtration
Fluid movement out of blood
Define: absorption
Fluid movement into blood
How do lipid insoluble substances cross capillary walls?
Through intercellular cleft
Intercellular cleft
Space between endothelial cells (paracellular pathway)
Permeability of capillary pores for difference substances varies according to…
How big the molecule is
Capillary permeability depend on…
- size of molecule
2. type of capillary
What is the space between cells called?
Interstitium
What is the fluid in the interstitium called?
ISF
Interstitium
space between cells
2 major solid structures in interstitium
- Collagen fibres
2. Proteoglycan fillaments
Proteoglycan filaments
coiled molecules composed of hyaluronic acid
Most of the ISF is composed of…
- fluid proteoglycan mixtures (gel)
2. some free fluid (very little amount)
