Anatomy and Physiology II: Lecture Exam One

Distinguish between the pulmonary and systemic circuits (circulatory routes)

- Pulmonary circulation - carries blood from heart through lungs back to heart. Allows for exchange of gases w/in lungs where CO2 is exchanged for O2 - Systemic circulation - carries oxygenated blood from heart to tissues and organs of body and returns O2-poor/CO2-filled blood back to heart

Compare and contrast continuous, fenestrated, and sinusoidal capillaries in terms of structure and location

1) Continuous capillaries = plasma membranes form a continuous, uninterrupted ring around the lumen. Found in skeletal, smooth muscle, CT, and lungs. 2) Fenestrated capillary = endothelial plasma membranes contain pores. Found in glomeruli of kidneys and villi of small intestine. 3) Sinusoids= contain spaces between the endothelial cells with basement membranes being incomplete or absent. Found in liver and spleen.

Name the function of the heart valves

1) To open correctly so that blood can empty from the chamber, and 2) to close properly so that blood cannot flow the wrong way

Outline the phrases of the cardiac in terms of what is happening in the ECG trace, mechanical events (contraction and relaxation), atrial pressure, ventricular pressure, ventricular volume, aortic pressure, and timing

1. Relaxation period-follows T wave, ventricular pressure drops, SL valves close, isovolumetric relaxation for brief time. When ventricular pressure drops below atrial pressure, AV valves open (0.4 seconds) 2. ventricular filling- rapid ventricular filling occurs after AV valves open. SA nodes fires (P wave), atria contract & remainder of ventricular filling occurs. Ventricles have completed filling=end diastolic volume. Atria relax, ventricles depolarize (QRs complex 0.1s) 3. ventricular systole- impulse passes through AV node & then through ventricles. Ventricles contract. Ventricular pressure increases rapidly, AV valve close: isovolumetric contraction phase (constant volume)= start of contraction to opening of SL valves (0.05s). Ventricular ejection phase= open of SL valves to closing of SL valves. End systolic volume reached when ventricle finishes emptying (0.3s)

Explain the significance of each component of the cardiac conduction system and trace how the cardiac impulse travels through the myocardium

1. Sinoatrial Node (SA): located in uppermost atrial wall. It is the pacemaker component. Impulses travel throughout the atrial fibers via gap junctions in intercalated discs to the 2. Atrioventricular Node (AV): located in interarterial septum. Serves as delay signal that allows for ventricular filling. Cardiac impulse then moves to the 3. Atrioventricular bundle: only electrical connection b/w atria & ventricles. Located in superior interventricular septum. Impulses enter both 4. R&L bundle branches lead downward through interventricular septum toward apex & finally impulse reaches 5. Purkinje fibers: large diameter conduction myofibers located within papillary muscles of ventricles. Conducts impulse to mass of ventricular muscle tissue. Causes ventricles to contract which forces blood out.

List the functions of lymph, noting its major function

1. Transports foreign particles to the lymph nodes!! 2. returns small leaked plasma proteins back to the bloodstream 3. transports lipids and lipid-soluble vitamins absorbed in the GI tract to the bloodstream

Discuss the function of anchoring filaments that surround lymphatic capillaries

1. are microscopic closed ended tubes that extend into interstitial spaces; 2. receive lymph through their thin walls; 3. are associated with anchoring filaments, which serve an important function during edema (discussed later); 4. are located throughout the body, except in: a. avascular tissues; b. CNS; c. splenic pulp; d. bone marrow. 5. include lacteals that are lymphatic capillaries within villi of the small intestine.

Outline the negative feedback loop involving the hormone erythropoietin

1: Liver and spleen macrophages destroy worn RBCs. 2) Hemoglobin is broken into globin and heme. 3) Iron in Hb is recycled. 4) Heme is broken into biliverdin > bilirubin > bile. Then! The loop happens. Low blood oxygen causes the kidneys and liver to release erythropoietin. Erythropoietin travels to red bone marrow and stimulates the production of red blood cells that carry oxygen to tissues.

Describe the structure of the heart in terms of its blood vessels

2 types. 1) Arteries, which carry blood away from the heart. They a) carry bood that is high in O2 and low in CO2, except pulmonary arteries, which are low in O2 and high in CO2. Aorta carries blood from the left ventricle to the body. Pulmonary arteries carry blood from the right ventricle to the lungs (via the pulmonary trunk). Coronary arteries carry blood to the myocardium. 2) Veins, which carry blood toward the heart. Veins carry blood that is high in CO2 and low in O2, except for the pulmonary veins, which are high in O2 and low in CO2. Superior vena cava brings blood from the head and upper limbs. Inferior vena cava brings blood from the trunk and lower limbs. The coronary sinus (posterior surface) brings blood from the myocardium. All of the above deposit blood into the right atrium. The pulmonary veins bring blood from the lungs to the left atrium (2 from right lung, 2 from left lung). Note the ligamentum arteriosum, which is a remnant of the fetal ductus arteriosus.

List the components transported in blood plasma

A) Water, 92%, serves as solvent, transport, temp regulation, site of metabolic reactions. B) Plasma proteins, 7%, all produced in liver, three types (albumin: maintains osmotic pressure of cells and trasnports fatty acids; globulins, alpha, beta, and gamma, which are antibodies; and fibrinogen, aids in blood blotting), C) Plasma gases (O2, CO2, N), D) Plasma nutrients (amino acids, monosaccharides, lipoproteins), E) Nonprotein nitrogenous substances (plasma wastes), F) Plasma Electrolytes, G) Regulatory substances (enzymes, hormones).

Discuss blood typing (A, B, O, AB) and transfusions in terms of the following: - the antigen present on a persons erythrocytes - the antibodies within the persons plasma - compatible donor types - incompatible donor types

A: - a antigen - anti-B - can receive: O, A - cannot receive: B, AB B: - b antigen - anti-A - can receive: O, B - cannot receive: A, AB O: - neither A nor B antigen - Both anti-A and anti-B - can receive: O - cannot receive: A, B, AB AB: - A and B antigens - Neither anti-A nor anti-B - can receive: O, B, A, AB - cannot receive: -

Distinguish between AV and SL valves in terms of location, structure, and when they close

AV valves- between atrium and ventricles, associated with the chordae tendineae, and papillary muscle. Close during each pump of the heart. SL valves lie within the pulmonary trunk or the aorta- close when ventricles are relaxed.

Describe the structure of the heart in terms of its coverings

Along with the four main layers of the heart, there are also multiple layers of the pericardium. They include the Visceral pericardium, percardial cavity, fibrous pericardium, and the parietal pericardium. The fibrous pericardium is the outermost layer of the pericardium. It's main purpose is to protect the heart, anchoring it to the surrounding walls, and preventing it from overfilling with blood. The Parietal pericardium is the secondmost layer of the skin. The main job that the parietal has is to separate the visceral pericardium from the fibrous pericardium. In between the Parietal pericardium and the Visceral pericardium is the pericardial cavity. This cavity is filled with pericardial fluid which serves as a shock absorber by reducing friction between the pericardial membranes. Finally the last and innermost layer of the pericardium is the visceral pericardium. Also called the epicardium, this layer separates the myocardium from the serous pericardium.

Compare and contrast the 3 types of blood vessels in terms of the following: - direction of blood flow (in terms of the heart) - wall structure (# of layers and components of those layers) - gas concentrations - pressure

Arteries: - carry blood away from heart - 3 layers (smaller lumens for higher pressure against thick walls) - high 02 low co2 - high pressure Veins: - carry blood to heart - 3 layers (larger lumen due to low pressure against walls) - low 02 high co2 - low pressure Capillaries: - exchange of H20 & chemicals b/w blood & tissues - 1 layer - gas concentrations depend - low pressure

Name the branches of the ascending aorta, aortic arch, thoracic aorta, and abdominal aorta, and denote what body region they supply with blood

Ascending aorta: - Right coronary artery (myocardium) - Left coronary artery (myocardium) Aortic arch: - brachiocephalic trunk - left common carotid artery - left subclavian artery Thoracic aorta: - intercoastals (intercoastal/chest muscles) - Superior phrenics (superior diaphragm) - Bronchial arteries (bronchi of lungs) - Esophageal arteries (esophagus) Abdominal aorta: - celiac trunk - superior mesenteric artery - inferior mesenteric artery - renal artery on left interior side, supplies kidneys w/ blood

Explain why the atria are passive chambers, while the ventricles are active.

Atria are passive bc they receive blood from the veins. The ventricles are active because they pump blood from the heart into arteries.

Describe the structure of the heart in terms of its valves

Atrioventricular valves (aka AV valves): tricuspid valve is between RIGHT atrium and ventricle, bicuspid (the mitral valve) is between LEFT atrium and ventricle. Structures associated with the AV valves are chordae tendineae, which are tendon-like, fibrous cords that connect the cusps of AV valves to the papillary muscle (inner surface) of ventrices- this prevents cuss from swinging back into atria. The papillar muscle is the muscular columns that are located on the inner surface of the ventricles. Semilunar valves (aka SL valves): pulmonary SL valve lies within the pulmonary trunk, and the aortic SL valve lies within the aorta.

Explain why the solid portion of blood, formed elements, packed cell volume, or hematocrit are all composed of approximately 99% erythrocytes

Because they are the most abundant blood cell.

Explain why red bloods cells cells a relatively short lifespan

Because they don't have a nucleus they cannot reproduce. They get "beat up" traveling through the blood vessels over the 120 day lifespan.

Describe blood according to its tissue type and major functions

Blood is a connective tissue whose cells are suspended in a liquid called plasma. It functions to transport substances between body cells and the outside, as well as maintain homeostasis and protection.

Name the average volume of blood in a human

Blood is about 8% of body weight; about 4-6 liters depending on the size of the human

Define the term blood pressure, name the type of blood vessels where blood pressure is significant, and name the normal (average) value in a resting adult

Blood pressure = pressure exerted by blood on the wall of a blood vessel. Pulse= pressure wave that travels through arteries following left ventricular systole. Strongest in arteries closest to heart. Most commonly referred to is arterial blood pressure (blood pressure in veins is essentially insignificant). Arterial blood pressure rises to maximum during systole (contraction) and falls to its lowest during diastole (relaxation). In a normal adult at rest, the BP = 120 mm Hg / 80 mm Hg.

Discuss the factors that affect cardiac output

CO is affected by stroke volume and heart rate.

Define the terms cardiac output (CO), heart rate (HR), and stroke volume (SV)

CO= volume of blood pumped by each ventricle in 1 min (= to HRxSV); HR= # of heartbeats per unit time; SV= end diastolic volume-end systolic volume

Discuss the major event that occurs at capillaries

Capillaries permit the exchange of gases, nutrients, and wastes between blood and tissues. Connects arterioles to venules.

Define/describe the terms chordae tendiae, papillary muscle, and trabeculae carnae

Chordae tendiae: Tendon-like, fibrous cords that connect the cusps of AV valves to the inner surface of the papillary muscle. Papillary muscle: Muscular columns that are located on the inner surface of the ventricles. Trabeculae carne: Irregular inner surface (ridges and folds) of the ventricles.

Explain what is meant by the human cardiovascular system being a "closed system"

Circular system tubes carry blood away from heart, transport it to all of the body tissues then returns it to the heart

Define the term agglutination

Clumping of RBCs, which occurs when an antibody (in recipient's plasma) encounters its specific antigen (on donor RBCs).

Define the term anastomosis

Communication between arteries or between veins by means of collateral channels.

Name the process by which a leukocyte leaves the blood stream and enters a tissue (is this normal?)

Diapedesis. Occurs in injury, trauma, infection, etc.

Distinguish between granulocytes and agranulocytes, name the leukocytes in each category, and list the specific function of each cell type

Granulocytes have granules in their cytoplasm and a short lifespan - neutrophils: first to arrive at infection site - eosinophils: moderate allergic reactions - basophils: release histamine to stimulate inflammation Agranulocytes: Lack noticeable granules - lymphocytes: consist of T and B cells which are important in immunity - monocytes: leave bloodstream to become macrophages

Track a drop of blood through the following circulations: - heart/lungs/heart -through the myocardium - to the body (in general)

Heart/lungs/heart: -1) Right atrium (deoxygenated blood), through the tricuspid valve, to the 2) right ventricle, through the pulmonary semi-lunar valve, to the 3) pulmonary trunk, 4) the pulmonary arteries, then 5) the capillaries (alveoli) in lungs, then 6) the pulmonary veins, then 7) the left atrium and through the bicuspid or mitral valve to the 8) left ventricle, through the aortic semi-lunar valve to the ascending 9) ascending aorta. Through the myocardium: - 1) Oxygenated blood from the ascending aorta through the semi-lunar valve to the 2) left and right coronary arteries, to the 3) capillaries of the myocardium (gas exchange), through the 4) cardiac veins (deoxygenated blood, veins include great and middle cardiac vein), to the 5) coronary sinus, then to the 6) right atrium. To the body: - 1) Aorta through the semi-lunar valve to the 2) arteries, to the 3) arterioles, to the 4) capillaries in the body tissues to the 5) venules, then to the 6) veins, next to the 7) vena cavae, and finally to the 8) right atrium.

Name the primitive bone marrow cell from which all blood cells arise

Hemocytoblast

Outline and explain the three steps involved in hemostasis

Hemostasis = stoppage of bleeding from a blood vessel. 1) Blood vessel spasm (vessel walls constrict) a) vasospasm b) reduction in blood flow 2) Platelet plug formation a) platelets become sticky and adhere to one another b) platelets also release serotonin, which causes further vasoconstriction of the vessel 3) Blood coagulation (formation of blood clot)a) complex cascade of events (positive feedback mechanism)b) requires calcium ions c) two possible starting pathways I) Extrinsic clotting mechanism Starts when platelet contacts damaged tissue or tissue outside of a blood vessel (hence, extrinsic). Cascade leads to prothrombin activator (PA) release by platelets. PA and Ca2+ cause prothrombin to convert to thrombin. Thrombin catalyzes the polymerization of fibrinogen to fibrin. Fibrin threads make up the meshwork of the clot.II) Intrinsic clotting methodStarts when blood contacts a foreign substance. Same cascade as above.

Name the natural anticoagulant released by basophils and mast cells

Heparin

Discuss hypertension

Hypertension is high blood pressure that is a common condition in which the long-term force of the blood against your artery walls is high enough that it may eventually cause health problems, such as heart disease

Discuss where erythropoiesis occurs in adults and fetuses, and what other factors are needed for red cell production

In adults, hematopoietic stems cells are in the red bone marrow. In fetuses, this occurs in the yolk sac, liver, and spleen. B12, folic acid, and iron are all needed. Production is controlled by a negative feedback hormone called erythropoietin.

Describe the structure and function of the interventricular septum

Interventricular septum is a muscular wall that separates right and left ventricles. It prevents the mixing of oxygenated and deoxygenated blood.

Define the terms ischemia and hypoxia, and explain how they are related to the pathogenic conditions of angina pectoris and myocardial infraction

Ischemia: Reduction of blood flow. Hypoxia: reduced oxygen supply due to ischemia. Angina pectoris: "strangled chest" - severe pain that accompanies myocardial ischemia. Angina pectoris notes: a) crushing chest pain radiating down left arm, b) labored breathing, weakness, dizziness, perspiration, c) occurs during exertion, fades with rest, d) relieved by nitroglycerin. Myocardial infarction or heart attack- death portion of myocardium, usually caused by a thrombus or embolus (moving blood clot) in a coronary artery.

Discuss heart sounds in terms of what they represent, how they sound, how they are detected, and their significance

Lub= closing of AV valves (ventricular systole)-loud & long; Dub= closing of SL valves (ventricular diastole)- short & sharp if closing of valve cusps is incomplete, some blood may leak back (heart murmur)

Name the function of serous fluid around the heart

Lubrication between visceral and parietal pericardium in serous pericardium membrane.

Trace the flow of lymph from interstitial tissues to the bloodstream

Lymphatic pathways begin as lymphatic capillaries, which come together to form afferent lymphatic vessels, which lead to lymph nodes. The vessels that leave the lymph nodes are called efferent lymphatic vessels, which come together to form lymphatic trunks, which lead to two collecting ducts, which finally join the subclavian veins, where the lymph enters the cardiovascular system.

Trace a typical ECG and label each wave or complex and explain what event of the CCS corresponds to each wave

P wave- represents atrial depolarization, spreads from SA node throughout both atria; QRS complex- begins downward deflection, continues as large, upright, triangular wave, ends as downward wave, represents onset of ventricular depolarization; T wave- dome-shaped, upward deflection, represents ventricular repolarization

Name the two major components of blood and the percentage of each by weight

Plasma: 55% RBCs: 45% WBCs/Platelets: less than 1%

Distinguish between pulmonary, coronary, and systematic circulation

Pulmonary - lungs. Coronary - heart itself. Systemic - whole body.

Give the common and scientific name for the three types of blood cells, and describe each in terms of their circulating concentration in a normal individual, overall function, and key characteristics

Red blood cells (erythrocytes). These carry oxygen from the lungs to the rest of the body. White blood cells (leukocytes). These help fight infections and aid in the immune process. Types of white blood cells include: Lymphocytes. Platelets (thrombocytes). These help in blood clotting.

Explain why the refractory period between cardiac muscle contractions is so long

Refractory period = time following a contraction when a second contraction cannot be triggered. It is longer than the contraction itself because it is necessary for ventricles to relax and fill with blood before again contracting to eject the blood.

What does the renal artery/vein supply

Renal arteries: normally arise off the left interior side of the abdominal aorta, immediately below the superior mesenteric artery, and supply the kidneys with blood. Each is directed across the crus of the diaphragm, so as to form nearly a right angle. Renal vein: they branch off the inferior vena cava and drain oxygen-depleted blood from the kidneys. As they enter the kidneys, each vein separates into two parts. The posterior veins assist in draining the back section of each kidney, while the anterior veins assist the front part

Discuss what is meant by Rh incompatibility and its consequences

Rh positive: Presence of antigen D or other Rh antigens on RBC membranes. Rh negative: Do not have the Rh antigens on RBC membranes. Anti-Rh antibodies form only in Rh-negative individuals in response to the presence of red blood cells with Rh antigens. The seriousness of the Rh blood group is evident in a fetus that develops the condition erythroblastosis fetalis or hemolytic disease of the newborn.

Define the term cardiology

Study of the heart and diseases associated with it.

Explain the processes by which materials are exchanged through a capillary

Substances pass through the capillary wall by diffusion, filtration, and osmosis. Oxygen and carbon dioxide move across the capillary wall by diffusion regulated by the partial pressure differences. Fluid movement across a capillary wall via the pores is determined by a combination of hydrostatic and osmotic pressure.

Name (and locate) the veins that deposit their blood into the atria of the heart (which atria? deoxygenated or oxygenated blood?)

Superior vena cava brings deoxygenated blood from the head and upper limbs into the right atrium. Inferior vena cava brings deoxygenated blood from the trunk and lower limbs into the right atrium. The coronary sinus brings deoxygenated blood from the myocardium into the right atrium. The pulmonary veins bring oxygenated blood into the left atrium- there are two from the right lung and two from the left lung.

Define the terms systole and diastole

Systole: phase of contraction Diastole: phase of relaxation

Define the terms tachycardia and bradycardia

Tachycardia: a heart rate that exceeds the normal resting rate Bradycardia: a heart rate that slower than the normal resting rate

Explain why a mature erythrocyte lacks a nucleus

The absence of nucleus in the red blood cells is the adaptation to accommodate more hemoglobin in order to carry more oxygen. The biconcave shape of the red blood cells increases the surface area for a better diffusion.

Name (and locate) the arteries that take blood away from the heart (from which ventricle? deoxygenated or oxygenated blood?)

The aorta carries oxygenated blood away from the left ventricle to the body. The coronary arteries carry oxygenated blood to the myocardium. The pulmonary arteries carry deoxygenated blood from the right ventricle to the lungs via the pulmonary trunk.

Describe the location, size, and orientation of the human heart

The heart is located in the chest between the lungs behind the sternum and above the diaphragm. It is surrounded by the pericardium. Its size is about that of a fist, and its around 14 cm long and 9 cm wide.

Name the organs that compose the lymphatic system and give three general functions performed by this system

The lymphatic system is closely associated with the cardiovascular system. - thymus gland, lymph nodes, lymphatic vessels, tonsils, and spleen. These organs work together to transport excess tissue (interstitial) fluid to the blood stream, transport dietary fat, and help defend the body against disease causing agents.

Explain how lymphatic vessels are similar to veins

They are quite unlike in terms of what they carry (lymphatic fluid vs. blood). They are also quite different in that lymphatic vessels are sealed at one end, whereas veins form a full circuit with the other blood vessels. They are, however somewhat alike in that the liquid carried within them is pushed with relatively low pressure. In veins that's because the pressure drops after the capillary bed and in the lymphatics it's because they're not connected to the circulatory system. They both also use the "skeletal-muscle pump" which refers to skeletal muscles (the ones that are used for conscious movement, basically) moving and squeezing the vessels so that the liquid moves along. Both veins and lymphatics are valved to create directional flow of liquid. Without valves, liquid would just follow gravity.

Describe the final step in blood coagulation

Thrombin catalyzes the polymerization of fibrinogen to fibrin, and fibrin threads make up the meshwork of clot.

Identify the blood type considered the universal donor and the blood type considered the universal recipient

Universal donor: O Universal recipient: AB

Describe the structure of the heart in terms of its chambers

Upper chambers: atria. Right and left atrium are separated by the interatrial septum. Atria receive blood from veins, are thin walled chambers. Ear like flaps over the atria are called auricles, and note the fossa ovalis, the remnant of the fetal foramen ovale. The lower chambers: ventricles. Right and left ventricles are separated by the interventricular septum. Ventricles pump blood from the heart into arteries, are thick walled chambers. Note the trabeculae carnea, the irregular inner surface (ridges and folds) of the ventricles.

Describe how arterioles play a major role in regulating blood flow to capillaries

Vasoconstriction and Vasodilation

Give another name for epicardium

Visceral pericardium

Describe the structure of the heart in terms of its layers

Walls of the heart are composed of three layers. 1) epicardium (aka visceral pericardium), 2) myocardium, the cardiac muscle tissue, which composes the bulk of the heart, and 3) endocardium, the smooth inner lining of the heart chambers and valves.

What does the hepatic portal vein supply

a blood vessel that carries blood from the gastrointestinal tract, gallbladder, pancreas and spleen to the liver. This blood contains nutrients and toxins extracted from digested contents.

Distinguish between afferent and efferent lymphatic vessels

afferent lymphatic vessels- lead to lymph nodes efferent lymphatic vessels- leave the lymph nodes

Discuss the factors that regulate heart rate

autonomic nervous system (para & sym), chemicals, age, sex, temperature, emotion, disease

Name four tissues that do not contain lymphatic capillaries

avascular tissues CNS splenic pulp bone marrow

Distinguish between the body fluids filtered by lymph nodes and those filtered by the spleen

body fluids filtered by lymph nodes- accomplished through phagocytosis by macrophages body fluids filtered by the spleen- macrophages remove and destroy bacteria and damaged or worn red blood cells and platelets through phagocytosis

Describe what happens to the thymus as one ages

decreases in size

Name the condition that occurs when lymphatic flow is obstructed

edema

Discuss the composition of interstitial fluid and lymph

interstitial fluid is composed primarily of water and dissolved substances including small plasma proteins, nutrients, wastes, gases, electrolytes, enzymes, and hormones; as protein concentration in interstitial spaces increases, its pressure increases, thus increasing pressure forces tissue (interstitial) fluid into the lymphatic capillaries

Give the special name for lymphatic capillaries within the wall of the small intestine

lacteals

List six primary body regions drained by lymphatic trunks

lumbar intestinal bronchomediastinal subclavian jugular intercostal

Name the vein that each of the two collecting ducts deposit their lymph

lymph is deposited into the subclavian veins

Discuss the structure, location, and major function of lymph nodes

lymph nodes are located along lymphatic pathways, contain lymphocytes and macrophages, which destroy invading microorganisms; size is usually less than 2.5 cm, and shape is bean-like, with blood vessels, nerves, and efferent lymphatic vessels attached to the indented region (hilum); node is enclosed in a dense CT capsule that extends into the node and subdivides it into nodules

Name the cell responsible for the filtering action of the lymph node and spleen

macrophages

What does the temporal artery supply

one of two terminal branches of the external carotid artery. It supplies the temporalis muscle and the scalp and, as a donor artery, it supplies vascularity to the temporoparietal fascia

Name the common term for the sinoatrial (SA) node

pacemaker

Name the two lymphatic collecting ducts and indicate the portion of the body that is drained by each

right lymphatic duct- drains right upper body (25% of the body) thoracic (left lymphatic) duct- drains the remaining 75% of the body's lymph

Name the hormone that platelets within a platelet plug release that causes further vasoconstriction of a vessel

serotonin

Discuss the structure, location, and major function of the thymus

soft, bilobed organ; decreases in size (atrophy) after puberty; composed of lymphatic tissue that is subdivided into lobules; each lobule contains an outer (dark-staining) cortex filled with densely packed lymphocytes around a central medulla (light-staining) filled with swirled epithelial cells (Hassall's Corpuscles)

List the organs that compose the cardiovascular system and discuss the general functions of this system

the heart (cardiovascular), lungs (pulmonary), and arteries, veins, coronary and portal vessels (systemic). The system is responsible for the flow of blood, nutrients, oxygen and other gases, and as well as hormones to and from cells.

Define the term hematology

the science or study of blood, blood-forming organs and blood diseases

Discuss the structure, location, and major function of the spleen

the spleen resembles a large lymph node that is encapsulated and subdivided into lobules by connective tissue; contains two types of tissue: white pulp- lymphocytes arranged around central arteries and red pulp- blood filled sinuses (venous blood that also serves as a blood reservoir)

Explain the forces involved in the movement of lymph

the squeezing action of skeletal muscles; the low pressure in the thoracic cavity created by breathing movements, moves lymph up from abdominal to thoracic region; recall the presence of one-way valves

Name the hormone secreted by the thymus that causes maturation of lymphocytes that have migrated to other tissues

thymosin