E109_Lecture_12A_Fall2024 Blood Physiology PDF

Local control: myogenic autoregulation by stretch Myogenic autoregulation Increased blood flow Stretch smooth muscle Increase [Ca2+] -”activates myosin light- chain kinase in arterioles” Arteriole constriction Fig. 12-26 Local control: paracrin...

Local control: myogenic autoregulation by stretch Myogenic autoregulation Increased blood flow Stretch smooth muscle Increase [Ca2+] -”activates myosin light- chain kinase in arterioles” Arteriole constriction Fig. 12-26 Local control: paracrine/ hormonal control Paracrine control Changes in [O2] and [CO2] Nitric Oxide synthesis-vasodilation Other Paracrines-hormones Pournaras et al. (2008) Prog Ret Eye Res released by cells vs glands: Adenosine-vasodilater Prostaglandins-vasodilaters Thromboxane-vasoconstricter Sympathetic global regulation: tonic control Example-Norepinephrine=fight or flight hormone released by nerve cells leads to constriction and diversion. Increased AP frequency = increased NE release Decreased AP frequency = decreased NE release Time Time Action potential (AP) a-receptor See cool video https://www.youtube.com/watch?v=cocB-M3h9k0 Blood Lecture 12A Blood Lecture 12A Learning goals Chapter 15 Understand BV control and Baroreceptor reflex Learn the structure of capillaries Learn capillary function: it is all about pressure Global view of sympathetic response Elastic arteries Volumetric flow rate Aorta Aortic valve Left ventricle Left heart Mitral valve Arteriole with Left atrium variable radius Cardiac output Pulmonary veins Peripheral resistance te hedidfatExchange ofaflow pinched Lungs Capillaries material with cells Pulmonary artery Pulmonary valve Venules Right ventricle Right heart Tricuspid valve Right atrium Venae cavae Venous tone Expandable veins Flow Velocity Figure 15-1 HR-heart-rate CO-cardiac output R-Resistance Baroreceptor reflex: control over blood pressure Stimulus Sensory receptor Medullary Glossopharyngeal cardiovascular Integrating center control center Vagus-nerve Efferent path Effector Change in blood pressure Sympathetic on-increases Parasympathetic Parasympathetic on-decreases neurons Carotid and aortic So when one is on-the other baroreceptors Is off. There are also Sympathetic neurons SA node chemoreceptors that detect oxygen, Ventricles carbon dioxide, and Ph Veins Homeostatic Arterioles Negative feedback loop Hypertension and Atherosclerosis Cardio Vascular Disease Normal endothelium Excess LDL consumed by macrophages, attach to endothelium, form fatty streaks Normal=120/80 Socio-economic considerations fooddeserts Hypertension and Atherosclerosis Avoid Processed Sugar=turns into fat by liver Avoid LDL-fats and cholesterol Normal endothelium Eat HDL-fats lowprotiendenselipids Excess LDL consumed by macrophages, attach to endothelium, form fatty streaks Fibrous scar tissue forms around lipid core, calcifications arise Macrophages release enzymes that expose collagen, attract platelets for clotting  and endothager Atherosclerosis= Hardening of the arteries them getintothe endothelial IDI's bloodvessels causing an immuneresponse aimmuneresponse causes plaque diet Get “under” the endothelial layer Plaque ruptures Blood clot forms constantunhealthyeating habitscan causing plaqueto grow on walls to a plaque this increases risk cause rupture which can blood clots which aheart attack Atherosclerosis endothelial layer in blood vessle Hardening of arteries Normal endothelium Plaque formation Excess LDL consumed 1. LDL=Lowby(protein) macrophages, Density Lipids attach to endothelium, form the 2. Get “under” fatty streaks epithelial layer Fibrous scar tissue forms around lipid core, calcifications arise Macrophages release enzymes that expose macrophagesengulfLDL's die creating plaque collagen, attractFoam Cellsfor platelets Die and clotting contents build up=Plaque Continuous Capillaries have leaky junctions This is where the transfer of material occurs. Most common type Paracellular transfer (through)-small things like oxygenthruleakyjunctions Transcytosis- larger items-amino acids exocytosis thru moving us Figure 15-16a Fenestrated Capillaries have large pores pores Transporting epithelia Where: Intestine, kidney How: Diffusion through pores What: Bulk flow of many items Figure 15-17b Capillary filtration and absorption-Osmosis Water Osmotic pressure (p): Capillary filtration and absorption-Diffusion Bulk flow: mass movement of fluid due to pressure Blue arrows=out Red arrows=in varies Hydrostatic pressure (pressure aginst the walls (Pcap) Osmotic pressure (p): there are non-penetrating solutes and the osmotic pressure is constant at 25 mm Hg fluidgoingoutofbloodvessle Pcap = 32 mm Hg p = -25 mm Hg Net filtration p = -25 mm Hg Pcap = 15 mm Hg 32 15 - 25 - 25 7 mm Hg Net absorption -10 mm Hg fluidgoinginto mortietti 99,190 a bloodressies Arterial end Venous end wantnet filtrationonthe we becausewe want arterialside to get oxygen glucose to thecells Figure 15-18 Blood Lecture 12B Blood Lecture 12B Chapter 16 Learn what blood is and the cell types involved Understand that hemoglobin synthesis requires iron, and how we bring iron into the body Blood: plasma, RBCs, and WBCs Plasma Water (92% of mass) 55% Plasma Ions (e. g. , HCO" !) pH homeostasis Organic Molecules (proteins, lipid, 1% sugars-Energy) WBCs Trace Elements-Zinc, copper, iodine Gasses (CO2, O2) 45% RBCs Hematopoiesis: synthesis of blood cells Stem cells BONE MARROW Erythroblast Megakaryocyte CIRCULATION Reticulocyte Erythrocyte Platelets Neutrophil Monocyte Basophil Eosinophil Lymphocyte Figure 16-2 (2 of 2) Hematopoiesis: synthesis of blood cells Stem cells BONE MARROW Erythroblast Megakaryocyte CIRCULATION Reticulocyte Erythrocyte Platelets Neutrophil Monocyte Basophil Eosinophil Lymphocyte Figure 16-2 (2 of 2) Red-Bone marrow: site of blood cell production Stroma mooace's Steines Bone marrow Nutrient artery In Adults: Pelvis, spine, ribs, cranium, and Radial proximal ends of long bones artery Important morphology= highly are in RBC's bones vascularized ends the g Figure 16-4 Bone marrow: site of blood cell production RBCs Stem cell Nuclear expulsion Blast Platelets cells Megakaryocyte- Sinusoid polyploidal capillary largecell in bonemarrow that Stroma Produces platelets im'tnesi p.ir hickito gggme Fibroblasts Figure 16-4ab Erthyropoietin and Thrombopoietin Thrombopoietin (TPO) Hormone synthesized in liver Causes megakaryocyte maturity Erythropoietin (EPO) Hormone synthesized in kidneys Causes erythrocyte (RBC) maturity Red blood cell shape is important Swelled Normal: Biconcave Shriveled Figure 16-6 More surface area Flow is more laminar Flows faster 20–30 trillion red blood cells at any given time Hallmark of RBCs: hemoglobin Protein made up of 4 subunits/polypeptide chains containing a heme group that contains iron. Iron is a positive ion, and oxygen is a negative ion. So, 4 oxygen molecules bind to each hemoglobin. 260 million per RBC Hallmark of RBCs: hemoglobin Healthy adults have ~5 g of iron in their bodies RBCs have a shelf life of about 120 days Transferrin Erythroblasts Intestinal lumen Use for hemo. Fe DMT1 Fe FPT Fe TR Stored as ferritin-in liver Enterocytes(cells in Blood Bone Marrow intestine) DMT=divalent metal transporter; FPT=Ferroportin; TR=Transferrin receptor