33 - Characteristics of the blood vessels. Hemodynamic principles- characteristic of the vessels and blood. Hemodynamic indices. Volume and linear velocity of the blood flow in different parts of the vascular system and determining factors.

sections

function of blood vessels

structural differences between diff types of vessels

arteries

arterioles

capillaries

venules

veins

hemodynamics

blood flow

pressure differences

stroke volume

cardiac output

volume and linear velocity of blood flow in diff parts of vascular system

function of blood vessels

Blood vessels used for transport of blood , to supply, remove waste etc

structural differences between diff types of vessels

1. Arteries

   • Have thick muscular walls- withstand high pressure

   • Made up of smooth muscle

   • Walls are elasticated for flexibility

   • under control of the sympathetic nervous system.

   • Transport oxygenated blood away from the heart

2. Arterioles

   • Small branches of the arteries that lead into capillaries

   • Under sympathetic control

   • Constrict and dilate in order to regulate blood flow and pressure

3. Capillaries

   • Capillary cells are one cell thick, for quick diffusion Allow for exchange of nutrients and oxygen

   • Can be fenestrated, continuous, discontinuous

   • Transport blood at low pressure, connect arteries to veins

4. Venules

   • blood from the capillaries → vein

   • Many venules together form a vein

5. Veins

   • Have a large lumen to hold a lot of blood

   • Veins with valves- prevent backflow

   • Transport blood to the heart

   • Transport deoxygenated blood

   • Only pulmonary vein supplies oxygenated blood to the left atrium

   • Hormonal and negative feedback mechanisms help to maintain osmotic valve and pressure of the blood

arteries

1. Arteries

   • Have thick muscular walls- withstand high pressure

   • Made up of smooth muscle

   • Walls are elasticated for flexibility

   • under control of the sympathetic nervous system.

   • Transport oxygenated blood away from the heart

arterioles

1. Arterioles

   • Small branches of the arteries that lead into capillaries

   • Under sympathetic control

   • Constrict and dilate in order to regulate blood flow and pressure

capillaries

1. Capillaries

   • Capillary cells are one cell thick, for quick diffusion

   • Allow for exchange of nutrients and oxygen

   • Can be fenestrated, continuous, discontinuous

   • Transport blood at low pressure, connect arteries to veins

venules

1. Venules

   • blood from the capillaries → vein

   • Many venules together form a vein

veins

1. Veins

   • Have a large lumen to hold a lot of blood

   • Veins with valves- prevent backflow

   • Transport blood to the heart

   • Transport deoxygenated blood

   • Only pulmonary vein supplies oxygenated blood to the left atrium

   • Hormonal and negative feedback mechanisms help to maintain osmotic valve and pressure of the blood

hemodynamics

• is the factors that affect blood flow, pressure, resistance and other basic physical principles of a blood circulation.

• Properties of Cardiovascular System that Affect Blood Flow Pulsatile Flow, Contraction/relaxation of the heart

• Pressure changes from the heart beat.

blood flow

• Blood flow is pulsative- in arteries and veins

• Depends on:

  • pressure differences along vessel

  • radius of blood vessel

  • length of blood vessel

  • viscosity of blood

pressure differences

That is Parterial > Pvenous or Psystole > Pdiastole.

stroke volume

• Stoke volume SV- the amount of blood ejected during systole from a ventricle (70ml normally)

• SV= EDV-ESV [end diastolic volume – end systolic volume 140-70=70]

cardiac output

• Cardiac output CO- the volume of blood pumped by the heart per minute (mL /min)

• CO=SV x HR eg at 70 bpm 70 x 70 = 4900 ml/min

volume and linear velocity of blood flow in diff parts of vascular system

• blood flow- 5 l/min- velocity

• Linear flow velocity--In aorta-0.5m/s

• Capillaries- 0.5mm/s

• Vena cavae- 0.2m/s

• Pulse wave velocity aorta- 6-8m/s

Blood Lies Constantly to Vice Presidents