BIO 241 1st EditionExam # 2 Study Guide Lectures: 8 – 12Lecture 8 (February 2)Introduction to Blood VesselsCompare and contrast the differences between the major types of arteries.Elastic/Conducting/Large arteries are the biggest arteries like the aorta, common carotid and subclavian arteries, pulmonary trunk, and common iliac arteries. The tunica intima is the innermost followed by the internal elastic lamina and then the tunica media. The tunica media is perforated like Swiss cheese and is full of smooth muscle, collagen, and elastic fibers. The perforations allow for vasa vasorum. Following the media is the external elastic lamina and thenthe tunica adventitia. You cannot distinguish either of the laminas.Distributing/Muscular/Medium arteries are smaller branches that distribute blood to specific organs. This is the brachial, femoral, renal, and splenic arteries. Their laminas are often conspicuous. Resistance/Small arteries are too variable in number and location to specify names. They have little elastic tissue. The smallest of these are called arterioles which have very little tunica adventitia. They are the major control of how much blood tissues or organs receive. What are capillaries and their function?Capillaries serve a very important purpose of blood which is exchange and distribution. Nutrients, wastes, hormones, and leukocytes must pass between the blood and the tissue fluidsthrough walls of vessels. They consist of only an endothelium and basal lamina (surrounds endothelium and separates it from adjacent connective tissue). What are the type of capillaries?Continuous- Intercellular clefts (separates endothelial cells that are held by tight junctions)- Small solutes can pass but plasma proteins, platelets, and blood cells are held back- Most tissues like skeletal muscleFenestrated- Endothelial cells are riddled with patches of filtration pores (fenestrations)- Rapid passage of small molecules- Important in organs that engage in rapid filtration and absorption- Kidneys, endocrine glands, small intestine, and choroid plexuses of the brainSinusoids/Discontinuous- Irregular blood-filled spaces- Liver, spleen, bone marrow- Twisted, tortuous passageways- Wide gaps with no basal lamina- Most things including plasma proteins pass easilyHow are venules and veins different from arteries?- Same basic tunics- Larger lumen- Thinner tunica media- Very distensible- Valves- Veins have more tunica intima- Arteries have more tunica mediaLecture 9 (February 4) What is the blood reservoir?- Capillaries = 5%- Heart = 8%- Pulmonary vessels = 12%- Arterial system = 15%- Venous system = 60%particularly skin, liver, and spleenWhat is vasomotion?Vasomotion consists of the vasoreflexes which are quick and powerful means of altering blood pressure and flow.Know the four things that determine bulk flow and what they are from previous lecture.What is the net filtration pressure at the arterial end and the venous end?NFP = outward forces - inward forces. At the arterial end, its value is 10 mmHg. Because the value is positive, filtration is occuring. At the venous end, its value is -10 mmHg. Since the value is negative, absorption occurs.What happens when total cross-sectional area increases?Velocity decreases when TCSA increases and velocity increases when TCSA decreases. Imagine awater hose with no sprayer head. What are the principal determinants of BP?Cardiac output (SV x HR), blood volume, and peripheral resistance contribute to BP.Lecture 10 (February 6)What is a major function of arterioles?Systemic vascular resistance aka total peripheral resistance which is determined by vasodilation and vasoconstriction.Know the mechanisms of venous return.What aids nervous input to the cardiovascular center of the medulla?- higher brain centers – cerebral cortex, limbic system, hypothalamus- baroreceptors – monitor arterial blood pressure- chemoreceptors – monitor O2, CO2, and H+ in arterial bloodWhat is the medullary ischemic complex?It is part of the neural control and is an autonomic response to reduced perfusions of the brain. The medulla oblongata monitors its own blood supply. How does aldosterone work in hormonal control of BP?It promotes sodium retention in the kidneys and causes increased water retention, increased blood volume, and eventually increased BP.What is autoregulation and what is its metabolic theory?It is the ability of tissues to regulate their own blood supply. Inadequate perfusion:- Decreased O2 → vasodilation- Increased wastes (CO2, H+, K+, adenosine) → vasodilationAdequate perfusion:- VasoconstrictionLecture 11 (February 9)What is a major difference between lymphatic vessels and capillaries?The lymphatic system is closed, unlike the capillary bed region of blood vessels where it is open.How does the flow of lymph occur?- no official “pump”- one-way valves- pressure gradient- skeletal muscle pumps- respiratory pumpIs the left or right lymphatic duct larger?The left lymphatic trunk is much larger as it includes everything but the right arm and surrounding areas.What are bone marrow and the thymus gland considered to be?They are the primary lymphatic organs. How do lymph nodes work?Lymph flows in through afferent lymphatics, enters the subcapsular sinus, flows toward the hius.Once there, lymph slowly trickles through the node where it is filtered heavily by macrophages and lymphocytes. This ensures the lymph is cleaned. Know where the lymph nodes are distributed.Lecture 12 (February 12)Where is the thymus gland located in adults?Trick question: the thymus gland involves with age. What line of defense is non-specific?The second line of defenseWhat is antibody-mediated immunity directed against? Extracellular pathogens using B