Blood Vessels Flashcards
unit 1
arteries
carry blood away from heart
veins
carry blood towards heart
capillaries
exchange site for oxygen, nutrients, and waste
diffusion is the exchange
tunics
-intima
-media
-externa
tunica intima
innermost layer of a blood vessel, thin layer of endothelial cells and connective tissue
regulates blood vessel function
tunica media
middle layer of a blood vessel, composed of smooth muscle and elastic fibers
controls vessel diameter through vasoconstriction and vasodilation, regu
tunica externa
outermost layer of a blood vessel, made of connective tissue with collagen and elastic fibers
structural support
What are the three main types of blood vessels?
Arteries, Veins, Capillaries
What are the three tunics of blood vessels?
Intima, Media, Externa
What is the role of the endothelium in blood vessels?
It lines the lumen of blood vessels.
Define vasoconstriction.
Narrowing of blood vessels
Define vasodilation.
Widening of blood vessels
What are elastic arteries known for?
Largest diameter, pressure reservoirs
What characterizes muscular arteries?
Specific organs, thick tunica media
What are arterioles?
Small arteries that lead to capillaries
What are anastomoses?
Interconnections between blood vessels
Which organs have no or poor anastomoses?
Retina, kidneys, spleen
What are the types of capillaries?
- Continuous
- Fenestrated
- Sinusoid
What is a capillary bed?
Networks of capillaries for microcirculation
What is the pathway from terminal arteriole to true capillary?
Terminal arteriole → metarteriole → precapillary sphincter → true capillary
What is the function of venules?
Collect blood from capillaries
What are the characteristics of veins?
Thin walls, large lumens, capacitance vessels
What causes varicose veins?
Dilated veins due to leaky valves
What is meant by ‘blood flow’?
Inverse to resistance
What does blood pressure measure?
Force by blood on vessel wall
What factors influence peripheral resistance?
- Viscosity
- Length of vessel
- Vessel radius
What drives circulation?
Pressure gradient
What is the Mean Arterial Pressure (MAP)?
Average blood pressure in a person’s arteries
What are the two components of Arterial BP?
- Systolic
- Diastolic
What are the mechanisms that help maintain blood pressure?
- Neural controls
- Hormonal controls
What is the role of baroreceptors?
Provide input to the cardiovascular center
What is orthostatic hypotension?
Reduced blood volume leading to drops in blood pressure upon standing
What are the vital signs related to blood pressure?
Pulse, pressure points, auscultatory method
What is the definition of hypertension?
> 140/90 mmHg
What is tissue perfusion?
Oxygen and nutrients delivered to cells
What factors control blood flow?
- Nitric oxide
- Endothelins
- Inflammatory chemicals
What is hypovolemic shock?
Shock due to decreased blood volume
What is cardiogenic shock?
Shock due to inadequate heart function