Information I will assume you to know heading into this weeks
lectures: Basic definition of veins vs. arteries. Elastic, smooth
muscle properties of arteries, veins, capillaries. Definition of
interstitial fluid, plasma, ECF Gradients for glucose, O 2, CO 2 at
capillaries Action of one-way valves and skeletal contractions in
helping venous return Basic aspects of RBCs no nuclei, no
organelles, no ribosomes.Hold hemoglobin Slide 2 Blood vessels are
more than little tubes bringing blood to your body They are
dynamic, changing flow, growing branches according to conditions
Slide 3 Reconditioning of blood Intestines, kidneys, and skin
receive blood flow in excess to their needs Slide 4 Flow rate of
blood Resistance is the opposition to blood flow through a vessel.
It depends on: blood viscosity vessel length vessel radius P R F=
pressure gradient resistance or Slide 5 Effect of radius on surface
area Friction increases as surface area of contact increases more
vessel wall contact with blood less contact Slide 6 Effect of
radius on resistance Slide 7 Arteries are a pressure reservoir
Large radius of arteries, little resistance Elastic recoil from
arteries drives flow of blood during diastole Arteries temporarily
expand and hold pumped blood Slide 8 Mean arterial pressure is the
driving force for blood flow. mean arterial pressure = diastole
pressure plus 1/3 the pulse pressure 80 + 1/3 (40) = 93 Blood
pressure drops sharply once in arterioles Slide 9 Arterioles give
most resistance Arteriole radius changes to alter the distribution
of blood and regulate blood pressure Vascular tone is a baseline of
vascular resistance - changes in radius are possible Slide 10 Local
control of arteriolar resistance Mean blood pressure is identical
to all organs Differences in arteriolar resistance determines the
distribution of blood to different organs Mechanisms: endothelium
cells release chemicals when O 2 and CO 2, acidity Slide 11 Slide
12 Figure 10.12 Page 354 Increased flow to skeletal muscles due to
exercise Slide 13 Extrinsic (outside) controls on arterioles:
Sympathetic signals cause general arteriole constriction,
increasing mean pressure Local controls dilate arterioles where
blood is needed. Slide 14 Increased SNS constrict Slide 15
Increased SNS constrict dilate Local controls using signals from
tissues Slide 16 Capillaries O 2, CO 2 nutrients and wastes
passively diffuse Thin vessels increase surface area of vessel wall
contact Slide 17 Diffusion at capillaries Distance: Walls are one
cell thick Area: small radius, high surface area of contact Speed:
small radius causes slow flow Slide 18 Capillary walls have pores
Pores allow the passage of small, water- soluble molecules (ions,
glucose) Lipid-soluble substances dissolve through cell membrane
Slide 19 Bulk flow Some substances cross the capillary wall by bulk
flow of fluids Ultrafiltration Reabsorption Slide 20 blood to venue
inward reabsorption tissue cells outward ultrafiltration blood Bulk
flow at capillaries Bulk flow occurs by the differences in
hydrostatic and osmotic pressures between plasma and interstitial
fluids Slide 21 Bulk flow at capillaries When fluids leave
capillaries, most plasma proteins remain Plasmaproteins blood to
venue inward reabsorption tissue cells outward ultrafiltration
blood Slide 22 Bulk flow at capillaries Plasma has a higher
concentration of proteins, producing osmotic pressure from
interstitial fluid to plasma Plasma-colloid osmotic pressure
osmotic pressure blood to venue inward reabsorption tissue cells
outward ultrafiltration blood Plasmaproteins Slide 23 Arteriole
Venule blood pressure (hydrostatic) 37 17 blood pressure
(hydrostatic) Plasma colloid pressure 25 Plasma colloid pressure 25
11 Ultrafiltration 9 Reabsorption Interstitial pressure 1 Forces of
bulk flow Slide 24 Bulk flow Fluid is exchanged b/w plasma and
interstitial fluid Site of short-term maintenance of fluid balance
Slide 25 Venule Arteriole Tissue cells lymphatic vessel Lymphatic
system also absorbs interstitial fluid Slide 26 Lymphatic System
Lymph formed from interstitial fluid Functions: Drainage channels
Absorption of fats from intestine Deliver pathogens to nodes where
there are many lymphocytes Slide 27 Fluid pressure fluid cannot
push out from inside Lymphatic vessels Slide 28 Problems with
vessels Aneurysm Hemorrhage Why do aneurysms form? Slide 29 Blood
pressure problems Hypertension Blood pressure over 140/90
Associated w/ smoking, stress, obesity Caused by high blood volume,
clogging of vessels, repeated constriction of vessels from stress
(Sympathetic NS) Slide 30 Blood pressure problems Hypertension
Blood pressure over 140/90 Baroreceptors can adjust to higher BP
High BP puts stresses on vessels, elasticity (atherosclerosis,
strokes) and stresses on heart (heart attacks), kidneys Slide 31
Blood pressure problems Treatments for hypertension: Low salt diet,
reduce stress, exercise ACE inhibitors (reduce blood volume) Alpha,
beta blockers (reduce sympathetic effects) Calcium blockers (reduce
cardiac contractions) Slide 32 Circulatory shock blood pressure
drops too low to serve tissues. From weak heart, blood loss,
dilation from allergic response Body compensates w/sympathetic
signals, fluid shifts Blood pressure problems Slide 33 Components
of blood Plasma Blood cells: erythrocytes leukocytes (WBC), and
platelets. Hematocrit is the % of blood occupied by RBC. (RBC)
Slide 34 What is plasma? Ions: mostly Na+ and Cl-. Gasses, waste,
nutrients, hormones Plasma proteins: Albumins establish an osmotic
gradient, carry some hormones Globulins (alpha, beta, gamma)
transport molecules, serve as antibodies Fibrinogen - blood
clotting Slide 35 Hemoglobin Heme - contains iron and binds with
one molecule of O 2 Globin - 4 protein chains Turns bright red when
combined with oxygen CO 2, CO, H + can also bind Slide 36 RBCs live
for about 4 months Spleen removes old RBCs RBCs are produced in
bone marrow from pluripotent stem cells Slide 37 Kidney controls
RBC production Kidney is sensitive to anemia and releases
erythropoietin Slide 38 Blood doping Erythropoietin (EPO) can be
synthesized and injected to illegally enhance endurance An athletes
own blood can be stored and reinjected to boost RBCs Hematocrit can
detect Slide 39 Causes of anemia? Anemia O 2 to tissues is low Due
to RBC, erythropoiesis, or hemoglobin Pernicious anemia lack of B
12 results in low RBC production Aplastic anemia bone marrow
production Slide 40 How the body repairs itself Initial response:
vascular spasm - reduces blood flow through the vessel platelet
plug - Aggregation of platelets. Platelets attach to areas with
exposed collagen These processes are stimulated by ADP Slide 41
Platelets Platelets are cell fragments that are functional for 10
days Reduce blood loss (maintain hemostasis) Platelets and a RBC
Slide 42 Prostacyclin and nitric acid Normal endothelium Inhibits
platelet aggregation Normal endothelium Prostacyclin and nitric
acid Positive feedback at injury site Initial stimulus is exposed
collagen Repair is contained to site of injury Platelets Vessel
wall ADP Collagen platelet plug forming Exposed collagen at injury
Slide 43 How the body repairs itself Stopping blood loss:
Fibrinogen (plasma protein) is converted into fibrin (thread-like
protein). This conversion is catalyzed by thrombin Fibrin threads
trap RBCs, forming a clot Thrombin is formed from inactive
prothrombin in plasma Slide 44 These final 6 slides will not be
shown but relate the information you should already understand from
Bio 101,101 or 115 Slide 45 smooth muscle endothelium elastic
tissue smooth muscle endothelium smooth muscle, elastic fibers
endothelium valve Artery Arteriole Capillary Vein Arteries contain
connective tissue with elastin and collagen Veins include valves
Not shown Slide 46 Interstitial fluid is an intermediary from blood
to cells 80% of ECF is interstitial fluid Not shown Slide 47 Main
nutrients Not shown Slide 48 Veins returning blood Veins have large
radii and low resistance. Walls are thin, not elastic Most blood
volume is in veins Not shown Slide 49 Veins Valves prevent
engorgement and backflow Sympathetic NS constricts veins to
increase venous return Skeletal muscles also help return Not shown
Slide 50 RBCs RBCs have no nuclei, ribosomes, or organelles Packed
with hemoglobin Doughnut-like shape Not shown
