Vascular System Part One

Objectives Trace the route taken by blood as it leaves, and then returns to the heart. Describe the structure of the walls of arteries and veins. Discuss the structure and function of the three classes of arteries. Describe the characteristics that make veins distinct from arteries. Discuss the structure and function of the three classes of veins. Describe the structure, function, and organization of capillaries.

Blood Vessel Layers Tunica intima Tunica media Lumen Tunica externa

Blood Vessel Layers Tunica intima Innermost layer Consists of endothelium Same as endocardium that lines hearts Smooth surface keeps blood flowing freely Prevents clots Chemicals that cause blood vessels to Dilate Constrict

Blood Vessel Layers Tunica media Middle layer Smooth muscle Innervated by autonomic nervous system Elastic tissue Allows blood vessel to change in diameter

Blood Vessel Layers Tunica externa Outer layer Strong and flexible Fibrous connective tissue Supports and protects

Aneurysm Portion of the vessel wall has weakened Causing the blood to balloon out

Types of Blood Vessels Arteries: Carry blood away from the heart Arteries = Away Veins: Return blood to the heart Capillaries: Connect the smallest arteries to the smallest veins Capillaries= Connect Sites for exchange of nutrients and oxygen

Categories of Arteries Conducting arteries elastic arteries Distributing arteries muscular arteries Arterioles resistance vessels

Categories of Arteries Largest Closest to the heart Branch and divide Grow smaller as they travel away

Categories of Arteries Conducting Arteries Expand as blood surges into the them Greatest ability to expand and recoil Recoil when ventricles relax Examples: Aorta Carotids

Categories of Arteries Distributing Arteries Carry blood to specific organs and areas of body Examples: Brachial Femoral Renal Arteries

Categories of Arteries Aterioles Smallest arteries Contraction of smooth muscle in walls Resist flow of blood to regulate BP Control blood flow to an organ

Veins Become smaller as they lead away from the heart Converge from smaller to larger Have thinner walls than arteries Not as much pressure Have a great ability to stretch Can constrict extensively

Veins Capacitance Vessels Stretch Carry varying amounts of blood Little to no change in pressure Constrict extensively Helps maintain BP Blood volume drops

Categories of Veins Venules Medium-sized veins Large veins

Categories of Veins Venules Smallest veins Collect blood from the capillaries Thin, porous walls Exchange fluid with surrounding tissues

Categories of Veins Medium-sized veins Convergence of venules Thicker, more elastic walls One-way valves to prevent black flow Example: Radial and Ulnar Veins

Categories of Veins Large Veins Convergence of medium-sized veins Thick tunica externa Examples: Vena Cavae Pulmonary Veins

Capillaries Microscopic vessels that link Aterioles and venules Are the exchange vessels Nutrients Waster Hormones Transfer between blood and tissue Have extremely thin walls Have very small diameters

Capillaries Tissue with high metabolic rates Liver Kidneys Myocardium Large number of capillaries

Capillaries Fibrous Connective Tissues Lower metabolic rates Tendons Few capillaries

Capillaries Epidermis Cartilage Lens of Eye Cornea of Eye No capillaries

Question Veins are called capacitance vessels because: A. they can constrict extensively. B. they can stretch. C. they convey blood back to the heart. D. they contain one-way valves.

Capillary Organization Exercise Rest

Capillary Organization Exchange vessels Organized into network of capillary beds Capillary Walls Single layer of endothelium Basement membrane

Capillary Organization Body does not contain enough blood to fill entire system Precapillary sphincter Beginning of each network

Capillary Organization Exercise = more oxygen required Sphincters open Blood fills capillary network Exchange occurs Rest= oxygen not required Blood bypasses capillary bed Flows into venule

Quiz Review Know your Matching Worksheet Know which blood vessel connect 2 sides of vascular system Know how capillaries are organized Know what conducting arteries are and how they function Know what the tunica intima is its function Know the correct order of vessels in arterial system

Homework Read Chapter 15 Review the Animations on the Davis Website Student Resources Use the flashcards to prepare for QUIZ House Call Due 11-22-2016 Quiz 11-22-2016 Test 11-23-2016 Chapter 15 Only Workbook due 11-23-2016 Lab Presentations 11-23-2016 following TEST

Vascular System Part Two

Objectives Explain the methods of Capillary exchange Diffusion Filtration Colloid osmotic pressure. Identify and explain the three main causes of edema. Trace the path of pulmonary circulation.

Capillary Organization Sinusoid Unique capillary Liver, bone marrow, spleen Irregular, blood-filled spaces More permeable Allow for the passage of large substances Blood Proteins

Capillary Exchange Walls allow for two-way exchange

Capillary Exchange Mechanisms of exchange Diffusion Filtration Osmosis

Diffusion

Capillary Exchange Mechanisms of exchange Diffusion Most important mechanism of capillary exchange Greater to lesser concentration Release chemicals to surrounding tissues Oxygen Carbon Dioxide Glucose Hormones Nutrients

Filtration

Filtration Filtration Occures close to the arterial side of capillary bed Metarteriole Pressure 30-35 mm Hg Tissue 2 mm Hg Pushes dissolved nutrients Plasma Glucose Amino Acids

Colloid Osmotic Pressure View animation on Mechanisms of capillary exchange

Colloid Osmotic Pressure Osmosis Blood moves toward venous end of capillary Blood Pressure inside capillary drops 10 mm Hg Drop in pressure allows: Proteins to exert colloid osmotic pressure Albumin pulls tissue fluid and waste Into capillaries

Question How does the cardiovascular system meet the metabolic needs of skeletal muscle during strenuous exercise? A. It maintains blood flow at stable rate. B. It opens up capillary beds in skeletal muscle. C. It temporarily diverts blood from the GI trace and brain to get extra blood to muscles. D. It dilates capillaries to approximately twice their original diameter to accommodate the extra blood.

Edema Fluid filters out of capillaries faster than it is reabsorbed Accumulation in tissues 3 Main Causes Increased capillary filtration Reduced capillary reabsorption Obstructed Lymphatic drainage

Edema Increased Capillary Filtration Capillary pressure drives filtration Rise = Rise Causes Kidney failure Poor venous return R sided ventricle failure

Edema Reduced capillary reabsorption Deficiency in albumin Slow reabsorption Causes Liver disease Burns

Edema Obstructed lymphatic drainage Absorbs 15% of fluid filtered by capillaries Obstruction = fluid accumulation Surgical removal

Pulmonary Circulation View animation on Pulmonary circulation

Pulmonary Circulation Routes the blood to and from the lungs Exchange of carbon dioxide and oxygen Does NOT supply lung tissue with oxygen Lung tissue is oxygenated through systemic circulation

Question Capillaries release oxygen and take up carbon dioxide from surrounding tissues through the process of: A. osmosis. B. filtration. C. diffusion. D. colloid osmotic pressure.

Test Review Reading- Chapter 15 Definitions to KNOW Resistance Vessels Siusoids Metarterioles

Vascular System Part Three

Objectives Name the regions of the aorta and the major arteries arising from each region. Describe the blood supply to the head and neck. Identify the principal veins of systemic circulation. Discuss the principles of a pressure gradient and how it relates to blood pressure and circulation.

Pulmonary Circulation View animation on Pulmonary circulation

Pulmonary Circulation 1. Blood leaves the right ventricle through the pulmonary trunk, which branches into the right and left pulmonary arteries. 2. The pulmonary arteries enter the lungs. 3. The pulmonary artery branches into lobar arteries (one for each lobe of the lung). These arteries branch into smaller and smaller arteries until ending at the capillary beds.

Pulmonary Circulation 4. The capillaries surround the alveoli, where the exchange of oxygen for carbon dioxide occurs. 5. The capillaries form venules, which merge to form veins. The veins merge until forming the pulmonary vein, which returns the oxygenated blood to the left atrium.

Systemic Circulation Ascending aorta Aortic arch Descending aorta

Systemic Circulation Supplies oxygen and nutrients to organs Removes waste

Systemic Circulation Arteries Arise from aorta 3 regions Ascending aorta Right and Left Coronary Arteries Aortic Arch Brachiocephalic Left common carotid Left subclavian Descending aorta Thoracic and abdominal cavities Diaphragm divides Thoracic aorta Abdominal aorta Blood Supply to liver

Systemic Circulation Abdominal Aorta Right common iliac artery Right leg Femoral Popliteal Left common iliac artery Left leg Femoral Popliteal

Pulses

Pulses Radial Most common site for routine assessment of heart rate Carotid/Femoral Common site during an emergency for assessment of heart rate

Principal Arteries Subclavian artery Thoracic aorta Celiac trunk Renal artery Axillary artery Brachial artery Superior mesenteric artery Inferior mesenteric artery Radial artery Common iliac artery Internal iliac artery External iliac artery Femoral artery Popliteal artery Anterior tibial artery Posterior tibial artery Dorsalis pedis artery

Arteries of the Head and Neck Point at which carotid artery branches Common carotid artery Vertebral artery Vertebral artery

Circle of Willis

Venous Circulation Body drains from organs and other parts Brings all back to Vena Cava

Principal Veins Internal jugular vein Cephalic vein Hepatic veins Medial cubital vein Great saphenous vein Popliteal vein

Venous Circulation Vena Cava Main Vein Superior Vena Cava Receives blood from above the heart Head Shoulders Arms Inferior Vena Cava Receives blood from below the heart Lower half of the body

Venous Circulation Superficial veins Reside near surface Deep veins Deep well protected areas Usually along side artery, nerve

Veins of the Head and Neck Internal jugular vein External jugular vein Vertebral vein

Hepatic Portal Circulation Inferior vena cava View animation on Hepatic-portal circulation

Hepatic Portal Circulation Veins empty to portal vein Portal vein empties into sinusoids Superior mesenteric vein converges here Sinusoids empties into hepatic vein Hepatic vein to inferior vena cava Allows for removal of Toxins Bacteria ETOH Storage of glycogen

Question Portal systems allow blood to: A. pass through two capillary networks before returning to the heart. B. pass through one capillary network before returning to the heart. C. bypass all capillary networks and return to the vena cava. D. shunt blood from one vein to another.

Principles of Circulation

Principles of Circulation Pressure gradient Blood moves away = pressure declines Greater the difference in pressure = greater the flow Resistance The greater the resistance = lesser the flow

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Vascular System Part Four

Objectives Summarize how cardiac output, blood volume, and resistance affect blood pressure. Explain the relationship between blood pressure, peripheral resistance and blood flow. Discuss why blood flow through the capillaries is slower than any other part of the vascular system. Describe the neural and hormonal regulation of blood pressure and flow. Describe how the skeletal muscle pump and the respiratory pump aid in venous return.

Factors Affecting Blood Pressure Cardiac output Blood volume Resistance CO = BP CO = BP Volume = BP Volume = BP Resistance = Flow and Pressure Resistance = Flow and Pressure

Factors Affecting Blood Pressure Blood pressure is determined by Cardiac output Blood volume Resistance

Factors Affecting Blood Pressure Cardiac output Heart beats harder = increased cardiac output Cardiac output increases = BP increases CONVERSLY Cardiac output decreases = BP decreases Exercise stops Heart is weak

Factors Affecting Blood Pressure Blood volume Blood volume declines = BP Falls Dehydration Hemorrhage Kidneys reduce urine output Boost blood volume = BP Rises

Peripheral Resistance Friction of blood against walls of vessels Peripheral vascular system Diameter Greatest influence on resistance Blood Viscosity

Peripheral Resistance Amount of friction depends upon Blood viscosity Greater the viscosity slower it flows Vessel diameter Greatest influence on resistance

Peripheral Resistance Force that must be overcome for blood to reach the tissues. Lower the peripheral resistance = lower the blood pressure Necessary or system would collapse BP must rise to overcome peripheral resistance

Critical Thinking BP declines as it moves away from the heart WHY?

Vasoconstriction

Vasodilation

Blood Velocity= Speed

Question Which condition would you expect to accompany atherosclerosis, a disorder in which arteries lose elasticity and fatty material builds up inside the vessels? A. Irregular heartbeat B. Low blood pressure C. Increased blood viscosity D. High blood pressure

Neural Regulation of Blood Pressure BP Parasympathetic impulses Vasodilation BP BP Sympathetic impulses Vasoconstriction BP View animation on Neutral regulation of blood pressure (baroreceptors)"

Hormonal Regulation of Blood Pressure A number of hormones raise blood pressure. Renin, angiotensin I, angiotensin II Aldosterone Antidiuretic hormone (ADH) Epinephrine and norepinephrine Atrial natriuretic peptide (ANP) causes blood pressure to fall.

Venous Return Fight the forces of gravity Skeletal muscle Respiratory pump

Venous Return Contracted skeletal muscles Relaxed skeletal muscles

Respiratory Pump

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