Anatomy 2 Exam 2

Elastic Arteries (Conducting Arteries)

thick-walled arteries near the heart, expanding and recoiling as heart ejects blood; contain substantial smooth muscle, but essentially inactive in vasoconstriction

Muscular Arteries (Distributing Arteries)

deliver blood to specific body organs; smaller than conducting but have a thick tunica media (more muscle, but less elastic); active in vasoconstriction; less capable of stretching

Arterioles (Resistance Arteries)

control flow into capillary beds via vasodilation and vasoconstriction; tissues served can be bypassed

Capillaries

exchange between blood and interstitial fluid; nutrients, wastes, gases, hormones, etc.; supply almost every cell except for cartilage, epithelia, cornea, and lens of eye

Capillary Beds

blood may go from a capillary into a true capillary or into a shunt

Precapillary Sphincter Function

regulate blood flow into true capillaries

Venule

very porous; allow fluids and WBCs into tissues; larger venules have one or two layers of smooth muscle

Vein

thinner walls with large lumens compared to corresponding arteries; tunica media is thin, but tunica externa is thick; large lumen and thin walls make these a good storage vessels (blood reservoirs)

Tunica Interna (inner most)

contains endothelium, simple squamous epithelium that lines the lumen of all vessels; forms a thick surface with flat cells to minimize friction as blood moves through lumen

Tunica Media (middle)

mostly circular arranged smooth muscle cells and sheets of elastin; regulated by sympathetic vasomotor nerve fibers (vasoconstriction or vasodilation); important in circulatory dynamics; bulkiest layer generally, maintains blood pressure and circulation

Tunica Externa (outer most)

composed largely of loosely woven collagen fibers to protein and reinforce the vessel, and anchor it to surrounding structures

Systemic Veins and Venules

60% of blood volume; supply all of the body except the lungs; are distensible; contain a large proportion of blood volume and are so called capacitance vessels or blood reservoirs

Venous Sinuses

flattened veins with extremely thin walls; composed only of endothelium

Anastomoses

provide alternate pathways to ensure continuous flow, even if a vessel is blocked

Portal System

blood flows from one capillary bed to another before returning to the heart (hepatic portal)

Arterial Blood Pressure

determined by the volume of blood forced into them at any time and the elasticity of the arteries close to the heart

Pulse Pressure

difference between systolic and diastolic pressure

Mean Arterial Pressure

pressure that propels blood to tissues; (diastolic + (1/3 systolic-diastolic))

Capillary Blood Pressure

low capillary pressure is desirable because high blood pressure would rupture fragile, thin-walled capillaries and most capillaries are very permeable, so low pressure forces filtrate into interstitial spaces

Venous Blood Pressure

changes very little during cardiac cycle, low pressure of venous side requires adaptations to help with venous return

Factors Aiding Venous Return

venous valves, muscular pump, respiratory pump, sympathetic venoconstriction

Regulating Blood Pressure

maintaining blood pressure requires cooperation of heart, the blood vessels, and the kidneys; the three main factors regulating blood pressure are cardiac output, peripheral resistance, and blood volume

Short-Term Regulation: Neural Controls

neural controls operate via reflex arcs, the cardiovascular center is composed of clusters of sympathetic neurons in the medulla; receives inputs from baroreceptors, chemoreceptors, and higher brain centers

Baroreceptor Reflexes

located in carotid sinuses, aortic arch, and walls of large arteries or neck and thorax; elicit adjustments if MAP is high or low

Chemoreceptor reflexes

aortic arch and large arteries of the neck detect increase in carbon dioxide, or drop in pH or oxygen; causes increased blood pressure by signaling cardio acceleratory center to increase CO and signaling the vasomotor center to increase vasoconstriction

Influence of Higher Brain Centers (Hypothalamus and Cerebral Cortex)

hypothalamus increases blood pressure during stress; mediates redistribution of blood flow during exercise and changes in body temperature

Short-Term Regulation: Hormonal Controls

short term via changes in peripheral resistance or long term via changes in blood volume; e.g. Epinephrine and norepinephrine, angiotensin, ADH, aldosterone, atrial natriuretic peptide (ANP)

Long-Term Renal Regulation

baroreceptors quickly adapt to chronic high or low blood pressure, so they are ineffective for long-term; long-term mechanisms control blood pressure by altering blood volume via the kidneys; direct renal mechanism and indirect renal mechanism (renal-angiotensin-aldosterone)

Primary Hypertension

no underlying cause identified; risk factors include heredity, diet, obesity, age, diabetes mellitus, stress, and smoking; no cure but can be controlled: restrict salt, fat, and cholesterol intake, increase exercise, lose weight, stop smoking, antihypertensive drugs

Secondary Hypertension

due to identifiable disorders including obstructed renal arteries, kidney disease, and endocrine disorders; treatment focuses on corrected underlying causes

Atherosclerosis

narrowing of arteries due to plaque buildup; can lead to hypertension; risk factors include age, being male, family history, high cholesterol, hypertension, cigarettes, sedentary lifestyle, diet, obesity and diabetes; treatments are coronary bypass, angioplasty, stent, and lifestyle changes

Tissue Perfusion

blood flow through body tissues involved in delivery of oxygen and nutrients to and removal of wastes from tissue cells, gas exchange in the lungs, absorption of nutrients in digestive tract, urine formation in the kidneys; rate of flow is precisely right amount to provide proper function to that tissue or organ

Intrinsic Control

control is entirely from within the tissue or organ; uses paracrine or properties of muscle tissue; also known as autoregulation or local control; metabolic or myogenic control; distribute blood flow to individual organs and tissues as needed

Extrinsic Control

control is from the outside of the tissue or organ; uses nerves or hormones; neural or hormonal controls; maintain mean arterial pressure; redistribute blood during exercise and thermoregulation

Capillary Exchange

speed is inversely related to total cross-sectional area; capillaries have largest area, so slowest flow; slow capillary flow allows adequate time for exchange between blood and tissues

Capillary Hydrostatic Pressure (HP_C)

capillary blood pressure that tends to force fluids through capillary walls

Interstitial Fluid Hydrostatic Pressure (HP_IF)

pressure pushing fluid back into vessel; usually assumed to be zero because lymphatic vessels drain interstitial fluid

Capillary Osmotic Pressure (oncotic pressure, OP_c)

“sucking” pressure created by nondiffusible plasma proteins pulling water back in

Interstitial Fluid Osmotic Pressure (OP_IF)

pressure is inconsequential because interstitial fluid has very low protein content

Lymphatic System

elaborate network of drainage vessels that circular ~3L of interstitial fluid per day; one-way system, ensuring lymph flows only toward heart

Lymphatics

network of lymphatic vessel

Lymph

interstitial fluid within lymphatic

Lymph Nodes

cleanse lymph

Lymphatic Capillaries

similar to blood capillaries, but more permeable, e.g. proteins, cell debris, pathogens, and cancer cells

Lymphatic Vessels

lymph capillaries drain into increasingly larger collecting vessels, trunks (named for regions of body they drain, and ducts; right lymphatic duct joins the right subclavian vein, thoracic duct joins the left subclavian vein

Lymph Transport

lymph system is a low-pressure system like venous system; lymph is propelled by the same mechanisms as venous blood flow; physical activity increases flow of lymph; immobilization of an area keeps needed inflammatory materials in area for faster healing

Edema

swelling caused by excess fluid in body tissues

Causes of Edema

increase in capillary hydrostatic pressure from incompetent venous valves, localized blood vessel blockage, congestive heart failure, or high blood volume; increase in interstitial fluid osmotic pressure from inflammation that increases capillary permeability and allows proteins to leak into interstitial fluid; decrease in capillary colloid osmotic pressure from hypoproteinemia that is low levels of plasma proteins caused by malnutrition, liver disease, or loss of plasma proteins from kidneys

Lymphedema

severe localized edema; caused by anything that prevents normal return of lymph to blood, ex. tumors blocking lymphatics or removal of lymphatic from surgery, lymphedema may improve if some lymphatic pathways remains and enlarge

Elephantiasis

pathology caused by blockage of lymphatic vessels that results in lymphedema in that area; most common underlying cause is a parasitic worm that blocks lymphatic vessels (filariasis)

Immune System Cells

T Cells (T Lymphocytes), B Cells (B lymphocytes), macrophages, dendritic cells

Supporting Cells

reticular cells produce fibers that provide network-like support for immune cells

Diffuse Lymphoid Tissue

loose arrangement of lymphoid cells and reticular fibers; found virtually in every body organ; particularly in loose connective tissue of mucosa

Lymphoid Follicles/Nodules

solid bodies consisting of tightly packed lymphoid cells; contain germinal centers of proliferating B cells; isolated aggregation (Peyer’s patches) or part of larger lymphoid organs

Primary Lymphoid Organs

thymus and red bone marrow; T and B cells originate in bone marrow, but only B cells mature there; T cells mature in thymus

Secondary Lymphoid Organs

lymph nodes, tonsils, spleen, peyer’s patches, appendix; areas where mature lymphocytes first encounter antigen and become activated

MALT

prevent pathogens from penetrating mucous membrane, site for lymphocyte activation and proliferation, largest collections found in tonsils, Peyer’s patches, and appendix; no capsule, no cortex or medulla, contains lymphoid follicles, diffuse lymphatic tissue in addition to follicles

Spleen

cleanses blood and removes aged or defective red blood cells, site for lymphocytic activation and proliferation, stores platelets, monocytes, and iron; yes capsule, no cortex or medulla, contains lymphoid follicles in white pulp, made of reticular connective tissue, has red and white pulp

Lymph Nodes

cleanse lymph, site for lymphocytic activation and proliferation; yes capsule, yes cortex and medulla, lymphoid follicles in cortex, made of reticular connective tissue, both afferent and efferent lymphatic vessels

Thymus

site of T cell maturation, blood thymus barrier, keeps immature T lymphocytes isolated from any antigens to prevent premature activation; yes capsule, yes cortex and medulla, no lymphoid follicles, made of epithelial tissues, has thymic corpuscles

Innate Defenses

surface barriers (skin, mucous membranes) and internal defenses (phagocytes, natural killer cells, inflammation, antimicrobial proteins, fever)

Adaptive Defenses

humoral immunity (B cells), and cellular immunity (T cells)

Intact Skin Dermins

forms mechanical barrier that prevents entry of pathogens and other harmful substances into the body; acid mantle of skin has skin secretions (sweat and sebum) that make epidermal surface acidic, which inhibits bacterial growth, also contains various bactericidal chemicals; keratin provides resistance against acids, alkalis, and bacterial enzymes

Intact mucous membranes

forms a mechanical barrier that prevents entry of pathogens, mucus traps microorganisms in respiratory and digestive tracts; nasal hairs filter and trap microorganisms in nasal passages; cilia propel debris-laden mucus away from nasal cavity and lower respiratory passages; gastric juice contains concentrations hydrochloric acid and protein digesting enzymes that destroy pathogens in the stomach; acid mantle of vagina inhibits growth of most bacteria and fungi; lacrimal secretions continuously lubricate and cleanse eyes and oral cavity as well as contain lysozyme, an enzyme that destroys microorganisms; urine normal acidic pH inhibits bacterial growth and cleanses the lower urinary tract as it flushes from the body

Phagocytes

second line of defense mechanism that work by engulfing and destroying pathogens that breach the surface membrane barriers; types are neutrophils and macrophages

Neutrophils

most abundant phagocytes, but die fighting

Macrophages

chief phagocytic cells; most robust

Inflammatory Process

triggered when body tissues are injured; inflammatory chemical release → vasodilation and increased vascular permeability → phagocyte mobilization (neutrophils flood area first; macrophages follow)

Complement System

consists of `20 blood proteins that circulate in blood in inactive form; provides major mechanism for destroying foreign substances; enhances both innate and adaptive defenses

Classical Pathway

activated by antibodies coating the target cell

Lectin Pathway

activated by lectins binding to specific sugars on microorganisms’ surface

Alternative Pathway

activated spontaneously, lack of inhibitors on the microorganisms’ surface allows the process to proceed

Interferons

cells infected with viruses that can secrete IFNs that warn healthy neighboring cells; IFNs activate NK cells and macrophages so they indirectly fight cancer

Fever

abnormally high body temperature in response to invading microorganisms; secreting pyrogens act on hypothalamus to raise the body temperature; benefits include liver and spleen sequester iron and zinc that are needed from microorganisms, as well as an increase in metabolic rate which increases rate of repair

Antigens

substances that can mobilize adaptive defenses; they are foreign substances that are not from the host body

Humoral Immunity

B cells can recognize soluble antigen for which their receptor is specific; primary response of initial encounter with the antigen and it binds to receptors on specific B cell, proliferating then occurs to form a clone with activated B cells, plasma B cells are created next, including the memory of B cell, antibody molecules are secreted; secondary response of re-exposure to the same antigen gives faster, more prolonged, more effective response

Active Humoral Immunity

naturally acquired - infection, contact with pathogen; artificially acquired - vaccine, dead or attenuated pathogens

Passive Humoral Immunity

naturally acquired - antibodies passed from mother to fetus via placenta, or to infant in her milk; artificially acquired - injection of exogenous antibodies (gamma globulin)

Humoral Immunity Antibody Defense Mechanism

antibodies and antigens combine to create an antigen-antibody complex; inactivated by neutralization, agglutination, and precipitation; all three of these processes enhance phagocytosis; triggers a complement activation that enhances phagocytosis and inflammation as well as leads to cell lysis

Immunoglobulins

capable of binding specifically with antigen to form complexes; IgM, IgA, IgD, IgG, IgE

IgM

pentamer; first immunoglobulin class secreted by plasma cells during the primary response; readily fixes and activated complement

IgA

dimer; secretory and is found in body secretions such as saliva, sweat, intestinal juice, and milk; helps stop pathogens from attaching to epithelial cell surfaces (including mucous membranes and the epidermis)

IgD

monomer; found on the B cell surface; functions as a B cell antigen receptor

IgG

monomer; most abundant antibody plasma, accounting for 75-85% of circulation antibodies; the main antibodies of both secondary and late primary responses; readily fixes and activated complement

IgE

monomer; stem end binds to mast cells or basophils; antigen binding to its receptor end triggers these cells to release histamine and other chemicals that mediate inflammation and an allergic response

Cytotoxic T (T_c) cells

directly attack and kill other cells; identifies foreign antigens on MHC I protein and binds tightly to target cell; releases perforin and granzyme molecules from its granules by exocytosis; perforin insert in target cell membrane, polymerize, and form transmembrane pores; granzymes enter target cell via pores and trigger apoptosis inside cell; T_c detaches and searches for another prey

Helper T (T_H) cells

without T_H, there is no immune response; works under humoral and cellular immunity

T_H cell Humoral Immunity

T_H cell binds with the self-nonself complexes of a B cell that has encountered its antigen and is displaying it on MHC II on its surface; T_H cell releases interleukins as co-stimulatory signals to complete B cell activation

T_H Cell Cellular Immunity

T_H cells bind dendritic cells; stimulated dendritic cell to express co-stimulatory molecules; dendritic cell can now activate CDB cell with the help of interleukin 2 secreted by T_H cell

Regulatory T (T_reg) cells

dampen immune response by direct contact or by secreting inhibitory cytokines

Hypersensitvity

immune responses to perceived (otherwise harmless) threat that cause tissue damage; different types- antibodies cause immediate and sub-acute hypersensitivities or T cells cause delayed hypersensitivity

Mechanisms of Acute Allergic Hypersensitivity Response

antigen (allergen) invades body; plasma cells produce large amounts of IgE antibodies against allergen; IgE antibodies attach to mast cells in body tissues (and to circulating basophils); more of the same antigen invades the body; antigen combines with IgE attached to mast cells (and basophils), which triggers degranulation and release of histamine (and other chemicals); histamine causes blood vessels to dilate and become leaky, which promotes edema; stimulates secretion of large amounts of mucus, and causes smooth muscles to contract

Autoimmune diseases

loss of ability to distinguish self from foreign; autoantibodies and sensitized T_C cells destroy body tissues; rheumatoid arthritis, T1 diabetes, Graves’ disease, lupus erythematosus; treatment is either suppressing entire immune system, or targeted immunotherapy

Immunodeficiencies

congenital or acquired conditions that impair functions or production of immune cells or molecules; ex. acquired immune deficiency syndrome (AIDS); human immunodeficiency virus (HIV) cripples immune system by interfering with activity of helper T cells

Respiratory System Functions

supply oxygen and dispose of carbon dioxide (cellular respiration), also functions in olfaction and speech

Respiratory System Four Processes

pulmonary ventilation which is the movement of air into and out of lungs; external respiration which is the exchange of oxygen and carbon dioxide between lungs and blood; transport of oxygen and carbon dioxide in the blood; internal respiration which is the exchange of oxygen and carbon dioxide between systemic blood vessels and tissues

Upper Respiratory Tract

nasal cavity, nostrils, oral cavity, pharynx

Lower Respiratory Tract

trachea, right and left bronchus (primary), right and left lung, diaphragm

Nose

airway for respiration, moistens/warms and cleans entering air, resonance and speech, olfactory receptors

Rhinitis

inflammation of nasal mucosa; continuous with mucosa and respiratory tract, so infections can spread from nose to throat to chest