Review Guide for Chapters 20-22: Circulation, Immunity, and Respiration

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Arteries

Carry blood away from heart.

Arterioles

Smallest branches of arteries.

Capillaries

Smallest blood vessels; location of exchange between blood and interstitial fluid.

Venules

Collect blood from capillaries.

Veins

Return blood to heart.

Tunica externa

Anchors vessel to adjacent tissues in arteries; contains collagen and elastic fibers.

Vasa vasorum

Small arteries and veins in walls of large arteries and veins that supply cells of tunica media and tunica externa.

Tunica media

Contains concentric sheets of smooth muscle in loose connective tissue; essential for vasoconstriction and vasodilation.

Vasoconstriction

The contraction of arterial smooth muscle by the ANS.

Vasodilation

The relaxation of arterial smooth muscle; enlarging the lumen.

Elastic arteries

Conducting arteries; large vessels with tunica media having many elastic fibers and few muscle cells.

Muscular arteries

Distribution arteries; medium sized with tunica media having many muscle cells.

Fenestrated capillaries

Have pores in endothelial lining; permit rapid exchange of water and larger solutes between plasma and interstitial fluid.

Sinusoidal capillaries

Have gaps between adjacent endothelial cells; permit free exchange of water and large plasma proteins between blood and interstitial fluid.

Medium sized veins

Thin tunica media and few smooth muscle cells; tunica externa with longitudinal bundles of elastic fibers.

Large veins

Have all three tunica layers; thick externa and thin media.

Blood pressure

The force exerted by the blood on the walls of the vessels and heart chamber.

Resistance

Factors that impede or slow flow of blood.

Viscosity

The thickness of blood.

Turbulence

Disruption of smooth flow of blood.

Mean arterial pressure (MAP)

MAP = diastolic pressure + 1/3 of the pulse pressure; pulse pressure = systolic pressure - diastolic pressure.

Hypertension

High blood pressure; specific numbers that constitute hypertension are not provided.

Systolic pressure

The pressure in the arteries during the contraction of the heart.

Diastolic pressure

The pressure in the arteries when the heart is at rest between beats.

Systolic

Arterial pressure from ejection of blood by ventricular contraction (systole)

Diastole

Arterial pressure during ventricular relaxation

Filtration

Fluid pushed out of arterial end

Reabsorption

Fluid pulled into venous end

Hydrostatic pressure

Pressure of fluid enclosed in a space, driven by pumping of heart into closed vascular system

Osmotic pressure

Draws fluid back in due to solute or water concentration at venous end

Net filtration pressure equation

NFP = (CHP - IHP) - (BCOP - ICOP) to determine the direction of movement of solutes

Baroreceptor reflexes

Carotid and aortic baroreceptor stimulation affected BP and respiratory centers

Renin-angiotensin-aldosterone-system (RAAS)

Helps maintain normal blood pressure; Renin converts angiotensinogen to angiotensin I, which is converted to angiotensin II by ACE

Erythropoietin (EPO)

Stimulates red blood cell production in bone marrow

Atrial natriuretic peptide (ANP)

Regulates blood pressure and volume by promoting sodium and water excretion; produced by atrium

Brain natriuretic peptide (BNP)

Helps regulate blood pressure and fluid balance; produced by ventricles

Fetal circulatory system

Key features include blood vessel organization within the umbilical cord, the role for the ductus venosus, the role of the foramen ovale, and the role for the ductus arteriosus

Lymphatic system roles

Carry excess interstitial fluid back to bloodstream, transport dietary lipids and vitamins absorbed in small intestines, filter pathogens from the blood, produce, maintain, and distribute lymphocytes

Lymphatic system organization

Lymphatic capillaries - small vessel - lymph nodes - larger vessels - lymphatic trunks - lymphatic ducts - subclavian vein

Major lymphatic ducts

Know the major lymphatic ducts and the regions of body each serves

Thoracic duct

Collects lymph from the left bronchomediastinal, left subclavian trunk, and left jugular trunk; empties into the left subclavian vein.

Inferior segment of thoracic duct

Part of the thoracic duct that collects lymph.

Right lymphatic duct

Collects lymph from the right jugular trunk, right subclavian trunk, and right bronchomediastinal trunk; empties into the right subclavian vein.

Lymphatic trunks

Drains lymph from lymphatic vessels and are named for the regions they serve.

Lumbar trunk

Drains lymph from the lower limbs.

Intestinal trunk

Drains lymph from abdominal viscera.

Intercostal trunk

Drains lymph from the thorax.

Bronchiomediastinal trunk

Drains lymph from the lungs and heart.

Subclavian trunk

Drains lymph from the upper limbs.

Jugular trunk

Drains lymph from the neck and head.

Lymphedema

Blockage of lymph drainage from a limb, causing severe swelling and interfering with immune system function.

Interstitial fluid collection

Occurs from blood to interstitial fluid through capillaries and returns to venous blood through lymphatic vessels.

Lymph transport

Lymph flows from lymphatic capillaries to larger lymphatic vessels containing one-way valves, traveling with veins and not actively pumped.

Lymph movement

Lymph is moved through vessels by muscle contraction, breathing, and one-way valves.

Lacteals

Special lymphatic capillaries in the small intestine that transport lipids from the digestive tract.

T-cytotoxic cells

Attack cells infected by viruses and produce cell-mediated immunity.

Memory T-cells

Provide specific activation against specific pathogens.

T-helper cells

Stimulate the function of T cells and B cells.

T-suppressor cells

Inhibit the function of T cells and B cells.

Mucosa-associated lymphoid tissue (MALT)

Lymphoid tissues associated with the digestive system that do not have capsules of connective tissue.

Lymph node properties

Contain trabeculae, bundles of collagen fibers extending from the capsule into the interior.

Afferent lymphatics

Carry lymph from peripheral tissues to lymph nodes.

Efferent lymphatics

Leave lymph at the hilum and carry lymph to venous circulation.

Natural killer (NK) cells

Identify and attach to abnormal cells, releasing perforin to lyse abnormal plasma membranes.

Thymus

Located in the mediastinum, atrophies after puberty, maintaining the blood-thymus barrier and secreting thymic hormones.

Spleen

Removes abnormal blood cells, cellular debris, and infected cells by phagocytosis; stores iron recycled from red blood cells.

Pathogen

An agent that causes disease, differentiated from innate and adaptive forms of immunity.

Physical barriers

Keep hazardous materials outside the body

Outer layer of skin

Part of the physical barriers that protect the body

Phagocytes

Attack and remove dangerous microorganisms (microphages and macrophages)

Immune surveillance

Carried out by natural killer cells

Interferons

Protein released by activated lymphocytes and macrophages

Complement

System of circulating proteins that assist antibodies in destroying pathogens

Inflammatory response

Triggered by any stimulus that kills or injures tissue

Fever

A systemic response to infection that can help the body fight pathogens

Fixed macrophages

Stay in specific tissues or organs

Free macrophages

Travel throughout the body

Activated macrophages

Respond to pathogens in several ways

Cytokines

Chemical messengers released by tissue cells to coordinate local activities

Alpha interferons

Produced by leukocytes; stimulate NK cells

Beta interferons

Secreted by fibroblast; slow inflammation

Gamma interferons

Secreted by T cells and NK cells; stimulates macrophage activity

Complement activation

2 pathways: Classical and Alternative

Classical pathway

Fast method where C1 binds to antibody molecule attached to antigen

Alternative pathway

Slow method exposed to antigen involving Factor P, Factor B, and Factor D

C3b

Active form of complement protein resulting from both pathways

Lymphopoiesis

Involves bone marrow, thymus, and peripheral lymphoid tissues

Antibody mediated immunity

A chain of events that destroys the target compound or organism

Major histocompatibility complex (MHC)

Cluster of genes that encode antigen-presenting molecules

CD4+ T-cells

Bind to class II MHC

CD8+ T-cells

Bind to class I MHC

IgM

1st made in primary response

IgG

1st in 2nd response; due to class switching

IgA

Exocrine secretions (mucous, saliva, tears, breast milk)

IgE

Allergies and anaphylaxis

IgD

B cell receptor

Primary immune response

The initial response of the immune system to a pathogen, characterized by the production of antibodies.

Secondary immune response

The immune response that occurs upon subsequent exposure to the same pathogen, resulting in a faster and more effective antibody production.

Naturally acquired, active immunity

Immunity gained through natural exposure to a pathogen, leading to the production of antibodies.

Artificially acquired, active immunity

Immunity gained through vaccination, which stimulates the immune system to produce antibodies.