Cardiovascular Flashcards
Functions of Cardiovascular System (7)
- oxygen transport and delivery
- nutrient transport and delivery
- waste transport and elimination
- hormonal transport
- temp. regulation
- BP regulation
- immune function
Circulatory Pathways (3)
- Pulmonary
- Cerebral
- Systemic
Components of Circulation
- Blood
- Heart
- Arteries
- Capillaries
- Veins
Blood Components
- Cellular
- Liquid
Total Blood Volume
- approx. 5 L
- greater volume for larger individuals, endurance trainers, and altitude-acclimated individuals
Arteries
- Elastic artery (resistance and greater in size)
- Muscular (large, small, arteriole, capillary)
Elastic Artery Layers
- Tunica intima
- Tunica media
- Tunica adventitia
Tunica Intima
innermost layer (squamous epithelial cells, endothelial cells, sub-endothelial, also lining of arterial wall)
- cells are flat and elongated
- parallel to the direction of blood flow in the artery
- gap junctions and zonula occludens keep endothelial cells attached to eachother
Tunica media
- middle layer
- smooth muscle
- controls blood flow by constricting and relaxing
Tunica adventitia
- outmost layer
- longitudinally arranged collagenous tissue -elastic fibers
- nerves are found here
Capillaries
- single layer of epithelium
- flow controlled by pre-capillary sphincters
Venules
-highest venous proportion of smooth muscle
Veins
- adventitia is not as elastic as arteries
- less tissue volume
- low pressure side of system
One way valves
- on venus side where pressure is low
- skeletal muscles are helpful moving the blood
Why are arteries called resistance vessels?
- b/c of the ability to constrict and dilate
- more elastic
- they control blood flow to the tissues
Why are veins called compliance vessels?
- b/c of the ability to distend
- at rest about 66% of blood is in the venus side
Determinants of Blood Pressure
- blood volume
- compliance ( = volume / pressure)
- cross-sectional area
Determinants of Blood Flow
- pressure gradient
- area
- viscosity
-determiants of blood flow also determine the diameter of the vessel.
Vasoconstriction and dilation influence what?
Blood volume
Vascular compliance and cross-sectional area determine what?
Blood pressure
Orthostatic of Hydrostatic Intolerance
- low pressure of venus side
- blood pooling
- problem for returning blood to hreat
- lack of return can result in dizziness
Resistance vessels
arteries that can adjust their caliber
Exchange vessels
-thin walled arterioles and capillaries that permit rapid exchange of oxygen, carbon dioxide, substrates, hormones, and other molecules
Capacitance vessels
-venules, small and large veins that can hold a large volume of blood
Hemodynamics
concerned with governing pressure, flow, resistance, volume, and compliance related to CV system
Hemodynamic pressure
produced by the contraction of the heart and stored in the elastic walls of the blood vessels�
Pressure
force applied over a surface
Hydrostatic pressure
-force of gravity acting on the blood
Transmural pressure
is the difference between the pressure inside and outside a blood vessel�
Compliance
a measure of the distensibility of a chamber expressed as a change in volume per unit change in pressure�
Mean circulatory filling pressure
pressure required to fill the blood vessels
Mean arterial pressure
pulsatile pressure averaged over the cardiac cycle
systemic vascular resistance
resistance to flow offered by the systemic circulation
Systolic pressure
peak in systemic arterial pressure (during ventricular systole)
Diastolic pressure
smallest pressure in systemic arterial pressure
Pulse pressure
the difference between systolic and diastolic pressures
Lymphatic vessels
are thin-walled and relatively permeable where a net transfer of fluid out of the vessels and into the interstitial space. These vessels return this fluid to the systemic circulation�
Lymphatic circulation
movement of fluid from the systemic and pulmonary circulation into the interstitial space and then back to the systemic circulation via the lymphatic vessels�
