Capillary Exchange Diffusion Transcytosis Bulk Flow Most important solute exchange method O2, CO2, glucose, a.a., hormones = [ ] gradients Plasma solutes cross capillary walls Blood-brain barrier = exception Transcytosis Enclosing substances in tiny vesicles. Endocytosis into cells. Bulk Flow Important regulation of relative volumes of blood and interstitial fluid Filtration Reabsorption

Capillary Exchange Blood hydrostatic pressure pushes fluid out of capillaries (filtration). Blood colloid osmotic pressure pulls fluid into the capillaries (reabsorption).

Figure 21.7 Capillary exchange Spend close to a full class going over this diagram. Use the written notes! Figure 21.7 Capillary exchange

Hemodynamics Factors affecting BF 4 main factors SV, HR, Pressure, Resistance

Blood Flow Volume of blood flowing through any tissue in a given time period. BF = BV mL/min Total blood flow = cardiac output BF= CO; (SV X HR) The same factors that change CO change BF Stroke volume: preload and contractility Heart rate: nervous system and chemicals

Blood Flow Distribution of CO to tissues depends on: Pressure difference Vascular resistance 4 factors affecting BF Ultimately controlled by contractility (large role) and endocrine system NE and E (lesser role)

Blood Pressure Pressure exerted by blood on the wall of an artery during ventricular systole and diastole. Pulse pressure Difference between systolic and diastolic pressures Mean arterial pressure The average BP in arteries

Blood Pressure BP CO , VR , BV (HR,SV) Blood itself has a role in BP More blood = é BP Less blood = ê BP Blood doping Dehydration Injury BV

Blood Pressure BP (MAP) = CO x R BP depends on total BV in system If resistance remains steady é CO = é BP ê CO = ê BP BP depends on total BV in system é BV = é BP ê BV = ê BP

Vascular Resistance Opposition to flow due to friction between blood & vessel walls 3 factors: Diameter of blood vessels Blood viscosity Total blood vessel length

Vascular Resistance Diameter of blood vessels Blood Viscosity Total blood vessel length Resistance is inversely proportional to the 4th power of the radius of the blood vessel R  1/ r4 The smaller the radius of the vessel = the greater the resistance it offers to BF Resistance is directly proportional to viscosity The greater the viscosity, the greater the resistance Pathology Hematocrit Resistance is directly proportional to blood vessel length Longer the vessel, greater resistance to blood that flows through it.

Systemic Vascular Resistance Total peripheral resistance All vascular resistances offered by systemic blood vessels Most in arterioles, capillaries, venules ** Arterioles

Figure 21.9 Venous Return Pressure gradient (contractions of L.V.) between venules and R.A. Valves Skeletal Muscle Pump* Respiratory Pump*

Figure 21.10

Figure 21.11

Blood Vessel Topics Components of the blood vessel system Basic structures of blood vessels Blood distribution Capillary exchange Factors affecting blood pressure and flow Control of blood pressure and flow Circulatory routes

Figure 21.12

Figure 21.13

Blood Vessel Topics Circulatory Routes – in lab Figure 21.17 21_17

Figure 21.18a 21_18a

21_18b 21_18b

21_19abc 21_19abc

21_19d 21_19d

21_20 21_20

21_21a 21_21a

21_21b 21_21b

21_21c 21_21c

21_21d 21_21d

21_22 21_22

21_23 21_23

21_24 21_24

21_25abcd 21_25abc

21_26a 21_26a

21_26b 21_26b

21_27 21_27

21_28a 21_28a

21_28b 21_28b

21_29 21_29

21_30ab 21_30ab

21_30c 21_30c

21_31 21_31

21_EX02 21_EX02

21_EX03 21_EX03

21_EX04 21_EX04

21_EX05 21_EX05

21_EX06 21_EX06

21_EX08 21_EX08

21_EX09 21_EX09

21_EX10 21_EX10

21_EX11 21_EX11

21_EX12 21_EX12

21_FOH 21_FOH