Blood and Circulation

Arteries

largest vessel

Elastic Arteries

propels blood

contains elastic fibers for stretch/recoil

Muscular Arteries

control blood flow into organs

lots of smooth muscle

Vasodilation

larger in diameter

increase in diameter=decrease of resistance

Vasoconstriction

smaller in diameter

decrease of diameter=increase of resistance

Arterioles

smallest blood vessel in diameter

Capillaries

gas and nutrient exchange

Continuous Capillaries

endothelial cells

complete basement membrane

found in most tissues

have gaps in between cells that allows for diffusion of small substances

Fenestrated Capillaries

contains little pores

no gaps between cells allows movement of large substances like waste, water, glucose

Discontinuous (sinusoid) capillaries

larger pores

no basement membrane

no gaps that allow for movement of bigger larger cells such as blood vessels or proteins

Precapillary Sphincters

controls blood flow through capillary beds

Capacitance

easily stretched veins

can have a lot of blood without the increase of blood pressure

Venules

receives blood from capillaries

Valves

Prevent backflow of blood

varicose veins

Veins that have non-functional valves

Anastomoses

two vessels that lead into the same tissue space

acts like a protection system

Poiseuille’s Law

Flow= difference in pressure/resistance

Turbulent Flow

slow and chaotic

Laminar Flow

fast and smooth

Perfusion

Flow through a mass in time

Blood Pressure

hydrostatic pressure against vessel wall

Arterial Pressure

Has the greatest flow

systolic pressure

pressure in the artery when ventricle contracts

Diastolic pressure

Pressure in artery when ventricles is relaxed

Resistance to Blood Flow

decreased flow=increased resistance=increased pressure

increased flow=decreased resistance=decreased pressure

Turbulence

resistance due to debris in vessel causing irregular flow

Viscosity

thickness of fluid

increased viscosity=increased resistance=decreased flow

decreased viscosity=decreased resistance=increased flow

Net Filtration Pressure

Filtration-Reabsorption

(BHP+IFOP)-(BCOP+IHP)

if answer is positive=filtration

if answer is negative= reabsorption

Filtration

movement of substances out of the vessel

move with water pressure from high to low

Reabsorption

osmotic movement of water INTO the vessel

pull of proteins

Hydrostatic Pressure

pressure water exerts on a vessel wall

Blood Hydrostatic Pressure

Filtration

Interstitial hydrostatic pressure

reabsorption

Osmotic Pressure

pull of proteins to move water

Blood Colloidal Osmotic Pressure

Reabsorption

interstial Fluid Osmotic Pressure

Filtration

Edema

swelling in tissues caused by excess fluid

increased BHP= increase of filtration= heart failure

decreased BCOP=decreased reabsorption= not enough proteins

lymph edema= lymph is blocked

Venous return

gravity

skeletal muscle pump

respiratory pump: change of pressure in chest

Cardiovascular Center

Cardioinhibitory: Parasympathetic

• Decreased Heart Rate=decreased cardiac output=decreased blood pressure

• decreased perfusion in digestion and skin

Cardio stimulatory: Sympathetic

• Increased Heart rate=increased contractility=increased cardiac output=increased blood pressure

• increase perfusion in skeletal muscle

Naturietic Peptide

release when Blood pressure is too high

increased urine output=decreased blood vol=decreased blood pressure

vasodilation

Antidiuretic hormone

released when osmotic pressure is too high

decreased water output=decreased urine output=increased blood vol=increased blood pressure

vasoconstriction

Angiotensin II

released from kidneys when BP is too low

potent vasoconstriction

kidneys retain Na+

increase aldosterone

increase Blood vol=increase BP