Studied by 1 person
What are the functions of peripheral circulation
Carries blood/transports substances
Exchange of nutrients, wastes, and gases
regulate BP
directs blood to/from tissue
What is the order of the blood moving through vessels
Aorta → arteries → arterioles → capillaires → venules → veins
What are the layers blood vessels
tunica intima
tunica media
tunica externia
What is the tunica intima
Endothelium
Smooth surface for blood flow
What is the tunica media
circular smooth muscle
site attachment for endothelial cells
Vasoconstriction and vasodilation
What is the tunica externa
External connective tissue layer
Expansion and recoil
What is the lumen
The center channel of a tubular structure
What are some differences between arteries and veins
Veins have valves
Arterial walls are thicker to withstand pressure
Veins have large lumen
What are the categories of arteries
Large elastic arteries
Muscular arteries
Arterioles
What are large elastic arteries
Elastic, so good for expanding during systole and recoil during diastole
Found in aorta and pulmonary trunk
What are muscular arteries
Constrict/dilate to alter blood flow to tissue areas
What are arterioles
Small arteries, maintains BP
Maintain slight contraction known as vasomotor tone
what are the three types of capillaries`
continuous
Fenestrated
Sinusoid
What are continuous capillaries
Has endothelial cells that create a lining, basement membrane, and small intercellular clefts
Found in the nervous system and muscles
What are fenestrated capillaries
Has endothelial cells that have fenestrations/pores in them (which makes it more permeable), basement membrane, and small intercellular clefts
Found in kidney and Gi tract
What are sinusoid capillaries
Has incomplete endothelial cells and basement membrane
Found in bone marrow, liver and spleen
What do capillaries connect to
The postcapillary venules
What percent of the body’s circulation volume is found in the veins at rest
55%
where is blood velocity the fastest
Elastic arteries
Because it has a small cross section
Where is blood velocity the slowest
Capillaries
Because it has a large cross section
What is capillary exchange
Process where cells receive substances need (arterial blood →tissue)
Eliminate waste (tissue →venous blood)
What is capillary exchange dependent on
Blood flow (pressure)
Blood content
What are the categories of capillary exchange
diffusion, vesicular transport, bulk flow
What is difusion
Movement down a concentration gradient
Movement of oxygen, carbon dioxide, glucose, ions
Pass through intercellular clefts or fenestrations (for larger solutes)
What is vesicular transport
Movement of hormones and fatty acids via pinocytosis
What is bulk flow?
Movement of large amounts of fluid down a pressure gradient
Filtration vs reabsoprtion
Filtration- bulk flow from blood capillary to interstitial fluid
Reabsorption- Bulk flow from interstitial fluid back to blood
What are the forces involved in capillary exchange
Hydrostatic pressure (HP)- pushing pressure
Colloid osmotic pressure- pulling pressure
What starling forces are inward
HP if
COP b
What starling forces are outward
HP b
COP if
What is net filtration pressure
Difference between the outward and inward forces
If outward forces exceed inward filtration is occurring
If inward forces exceed outward forces reabsorption is occurring
what veins is fluid returned at
Right and left subclavin veins
How does a balance of filtration and absorption exist?
Blood flow (HP) to tissue and plasma protein levels (COP) must be maintained
arteries, veins and lymphatic vessels must be obstruction free
What are some filtration and reabsorption imbalance issues
Aging → causes capillary permeability to increase
Liver disease → blood may not be synthesized
Kidney disease → allows proteins to escape
Blockage of lymphatic capillaries → inhibit reabsorption
Removal of lymph nodes
What can occur if there is an imbalance of filtration and reabsorption
Edema
What is blood flow proportional to
cardiac output
What is blood pressure
measure of force exerted by blood against blood vessel walls
What is a normal blood pressure
Less than 120 systolic
Less than 80 diastolic
What is pulse pressure
Difference bewtween SBP and DBP
Measures elasticity and recoil, representes the stress exerted on heart during systole
What is a normal pulse pressure?
40 mmHG
What is mean arterial pressure and how do you find it
It is the average pressure exterted on the arteries during a cardiac cycle
DBP + (PP/3)
Whats a good MAP
70-110 mmHg
Below 60 is bad
What are normal aterial and venous capillary pressures
Arterial- 40 mmHg
Venous- 20 mmHg
What is the volume of blood returning to right side of heart from systemic circulation called
venous return
What are three mechanisms of venous return
skeletal muscle pump
gravity
muscles of breathing within thoracic cavity do the same things as skeletal mucle
What is the skeletal muscle pump
Muscle bellies thicken during contraction and basically milk blood to the heart
what are the factors that affect resistance
viscosity of blood
vessel length
vessel radius
How is viscosity related to resistance
A high visocity means a higher resistance
how is vessel length related to resistance
The longer the vessel the more resistance
What is angiogensis
Blood vessel growth
Related to weight → as we gain weight out vesssels lengthen, which increase resistance and BP
Does blood in vessel flow faster in the center or on the wall
The center
what is total blood flow
amount of blood that moves through a vessel in a given period
How is blood pressure regulated in the body
Receptors
Control ccenter
effectors
What are baroreceptors vs chemoreceptors
baroreceptors- stretch
Chemorecptors- respond to chemical changes
What is the cardiovascular control center
The medulla oblongata
What are the subdivisions of the cardiovascular centers
cardioacceleratory center
Cardioinhibittory center
vasomotor center
What are the effectors
Heart and vessels
how is the chemical content of the blood impacted by under perfused tissue
A decrease in oxygen and nutrients
an increase in carbon, lactic acid, h+
