A & P 2 exam 2

Lymphatic system

protects us against disease from pathogens, transports materials (hormones, wastes and nutrients), returns excess fluid to bloodstream, and maintains normal blood volume

**Composed of:**

\-lymph

\-Lymph vessels

\-lymphoid tissue and organs

\-lymphoid cells (lymphocytes, phagocytes, ect)

three categories lymphatic cells respond to?

1\.) environmental pathogens (bacteria, viruses, ect)

2\.)Toxins (poisons, venom)

3\.)Abnormal body cells (cancer)

Immunity

the ability to resist infections and disease

primary lymphoid tissue

Place where lymphocytes are produced

\-include the red bone marrow and thymus

secondary lymphoid tissue

Place where lymphocytes are activated

\-Include tonsils, lymph nodes, spleen and MALT (mucosa-associated lymphoid tissue)(aka mucus membranes)

lymphatic vessels

carry lymph-interstitial fluid from peripheral tissue to venous return

\-contain minimal pressure

\-rely on valves to prevent backflow of lymph

\-contraction of SM aid flow

Lymphatic capillaries

tiny vessels that transports and filters lymphatic fluid (lymph) from your body's cells and tissues into lymphatic vessels

lymphatic vessels vs blood capillaries

**Lymphatic vessels are:**

\-Closed at one end

\-contain larger luminal diameters

\-have thinner walls

\-irregular outline in sectional view

Flow of fluid in lymphatic vessels

Overlap of endothelial cells act as one way valves. This prevents the return of things such as fluids, solutes, viruses, bacteria, ect from leaving the vessel once inside

(acts as a one way door where it can only open inward, not outward)

Lacteals

special lymphatic capillaries found in small intestine

\-transports lipids from Digestive tract

lymphedema

blockage of lymph drainage in limbs

\-results in severe swelling

where are lymphatic vessels located in the body?

in the peripheral tissues of the throat, armpits, chest, abdomen and groin (almost everywhere)

Lymphoid tissue

connective tissue dominated by lymphocytes

lymphoid nodules

areolar tissue with densely packed areas of lymphocytes

\-Found in lymph nodes, spleen, respiratory tract (tonsils), along reproductive, digestive and urinary tracts

germinal centers

central zone of each nodule, contains dividing lymphocytes

Lymphoid organs

Include lymph nodes, thymus, and spleen

Lymph nodes

small lymphoid organs that:

\- filter substances in lymph (purifies lymph before it reaches veins)

\-acts as early defense system (antigens in lymph stimulate macrophages and lymphocytes in nearby nodes)

\-monitor peripheral infections (respond before infection reaches vital organs)

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\*greatest amount found in neck, axillae and groin

\*largest nodes found in groin, axillae and base of neck

\*Nodes in gut, trachea and thoracic duct protect digest. and resp. tract

\*swells in response to infection

Trabeculae

bundles of collagen fibers which extend into the interior of nodes

Hilum

shallow indentation where blood and nervous vessels reach nodes

Afferent lymphatics

bring lymph to the lymph node from peripheral tissues

efferent lymphatics

vessels that carry lymph away from the lymph node and towards venous circulation

lymphadenopathy

excessive enlargement of nodes

thymus

located in mediastinum (where t cells are produced)

\-Atrophies after puberty

**thymic lobule**:

\-contains a dense outer cortex and pale central medulla

\-lymphocytes divide in cortex and migrate into medulla (this is where t cells leave)

what is/ the function of the spleen

the spleen is a specialized filter

* removes abnormal BC and other blood components
* stores iron recycles from ruptures RBC
* initiation of immune response by b and t cells

types of immunity

Innate: always works the same

adaptive: specialized responses depending on for antigen (develops after exposure)

lymphoid stem cells

**group 1 (lymphoid stem cells in bone marrow)**

\-produce B and NK cells

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**Group 2 (lymphoid stem cells migrates to thymus)**

\-produce t cells

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\*T cells differ in response to hormones while B cells differ in response to interleukins-7 (cytokines)

T cells

engage in cell mediated immunity (cell to cell combat)

types of T cells

1\.) cytotoxic T cells: attacks antigens physically and chemically

2\.)Helper T cells: stimulate responses of T and B cells

3\.)regulatory T cells: moderate immune responses

4\.) memory t cells: keeps record of previous encounters with pathogens (allows for quicker responses upon re-exposure)

Types of regulatory t cells

1\.) Inflammatory t cells: up regulate

2\.)Suppressor t cells: down regulate

B cells

engage in antibody- mediated immunity (defends against antigens and pathogens in body fluid)

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Types of B Cells:

1\.)Plasma cells; produce antibodies

2\.)Memory b cells: keep record of previous pathogen encounters

Do T and B cells retain their ability to divide?

yes, they maintain their ability to divide. There are allows a small number of lymphocytes (typically memory cells) circulating around the body. When a lymphocyte becomes exposed to the right antigen, it will produce many clones of it itself (with the same specificity)

\-allows for effective fighting against an antigen through combined t and b cell attacks

Clonal selection

the process of an antigen selecting particular lymphocytes for cloning

Innate defenses

block or attack any foreign substance/pathogen

types of Innate defenses

\-Physical barriers (skin, hair, mucous, stomach acid, ect)

\-Phagocytes (monocytes)

\-Immune surveillance (nk)

\-Interferons

\-complement

\-Inflammation

\-fever

Fixed macrophages (histiocytes)

stay in specific tissues and organs

Microglia

macrophages in CNS

Stellate macrophages

located on luminal surface of liver sinusoids

free macrophages

travel throughout the body

alveolar macrophages

monitor epithelial surfaces of lungs

what’s the Complement system?

system which enhances the action of antibodies and phagocytes (involves complement proteins in plasma)

\
\-complement proteins work in groups that can aid in pathogen destruction, opinization or histamine release

NK cells

take part in immune surveillance

\-secrete chemicals which lyse the plasma membrane of abnormal cells

Interferons (INFs)

small proteins released by activated lymphocytes, macrophages and infected tissues

\-they trigger the release of antiviral proteins by cells which block viral replication

Inflammation

localized immune response caused by damaged cells, antigens, pathogens, ect (causes vasodilation (heat, edema, redness, pain))

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\*activation of mast cells results in the release of histamine-→ triggers

effects of inflammation

\-Temporary wound repair through clot formation

\-slows spread of pathogens to other areas of the body

\-Mobilizes local, regional and systemic defenses in order to overcome pathogens and facilitate regeneration (removes debris and stim of fibroblasts)

Products of inflammation

1\.)Necrosis (local tissue destruction)

2\.)Pus (mix of debris, fluid, cells waste and dying tissue)

3\.)Abscess: collection of pus in an enclosed space

fever

temp greater than 37.2 degrees C (99 F)

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**Function:**

\-Increases metabolic rate (more chemical reactions=more release of Energy)

\-accelerates defenses since cells can move faster and enzymatic reactions r faster

\-slows replication of some viruses and bacteria

Pyrogens

released by bacteria, molds, viruses and yeasts

\-Causes hypothalamus to raise body temp

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\*endogenous pyrogens are produced internally and include interferons, interleukin-1, ect

immune surveillance

Carried out by NK cells'

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Steps:

1\.)Identify and adhere abnormal cells

2\.) Golgi bodies produced vesicles with perforins

3\.)perforins are released by vesicles

4\.) perforins form pores on plasma membrane of abnormal cell=lysis

cell-mediated immunity

Defends against abnormal cell and pathogens inside cells

\-Achieved through cell-mediated immunity

Antibody-mediated immunity

Defends against antigen and pathogens in body fluid (humoral immunity because antibodies are found in body fluid)

Four forms of immunity

1\.)Naturally acquired active immunity: developed in response to antigen exposure (undeliberate)

2\.)Artificially acquired active immunity: deliberate exposure to antigens through medical means (vaccines)

3\.)Naturally acquired passive immunity: antibodies which can be passed between individuals (breast milk, placenta)

4\.) already made antibodies received from an outside source through medical means (anti-venom

Four general properties of adaptive immunity

1\.) specificity (responds to specific antigens)

2\.)Versatility (many types of lymphocytes)

3.) Memory (memory cells provide protection against re-exposure)

4\.) Tolerance (immune system ignores self antigens)

MHC proteins

Membrane glycoproteins which bind to antigens (displays abnormal peptide on cell’s surface for t cell recognition)

class 1 MHC proteins

are in the plasma membrane of all nucleated cells

\-displays abnormal peptide on cell’s surface for t cell recognition= lysis of cell

\-triggered by viral or bacterial infection

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\*like a little red flag saying “I’m abnormal, kill me”

Class 2 MHC proteins

only present in membranes of APCs (include all monocyte-macrophage types, dendritic cells (Langerhans cells) of skin and those of lymph nodes and spleen

\-Class 2 MHC proteins only appears in plasma membrane during antigen processing (will engulf pathogen, break it down in antigenic fragments, display parts on cell surface for t cells)

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\*t cell receptors can bind to both 1 and 2 MHC, will only become activated (antigen recognition) for specific antigen

CD markers

cluster of differentiation markers in T cell membranes (reason for t cell specificity to certain antigens)

\-CD8: cytotoxic and regulatory t cells (responds to 1 MHC)

\-CD4: Helper T cells (respond to 2 MHC)

How are T cells activated?

T cells are activated by exposure to an antigen

* only recognize antigens presented by APC’s (present antigens to certain lymphocytes for recognition)
* Also need costimulation (secondary signal produced by abnormal target cell to confirm plan of action)

what produces memory t cells?

produced by cytotoxic t cells

* memory t cells can form cytotoxic t cells upon re-exposure to same antigen

How are B cells activated

1\.)Antigens in body fluid bind to receptors on b cell membranes=sensitization (antigen will reappear on b cell surface with 2 MCH

2\.)Helper T cell binds to 1 MHC and secretes cytokines the activate B cell

Constant segment

Same for all antibodies of that class (determines class of antibody)

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\*the vertical portion of the Y

Variable segment

part that is antigen specific

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\*the V portion of a Y

IgG

Largest and most diverse class of antibodies (part of secondary response because THEY TAKE LONGER TO PRODUCE)

\-can provide maternal immunity (cross the placenta)

\-Produces hemolytic disease

IgE

increases release of histamine and other inflammation chemicals by binding to exposed surfaces on basophils and mast cells

IgM

1st class of antibody secreted after antigen is encountered (part of primary response)

\-Anti A and Anti B antibodies

IgA

delivered through breast milk

cytokines

chemical messengers released by tissue cells (not hormones because they can be produced by most body cells, not exclusive to endocrine cells)

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Functions:

\-stimulate T cell division (which produces memory cells or quickens cytotoxic t cell maturation)

\-Attract and stimulate Macrophages

\-Promote activation of B cells

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ex. INFs

Immunocompetence

ability to produce immune response after antigen exposure

\-babies can develop this at 3 to 4 months old

respiratory system

composed of structures involved in ventilation and gas exchange

functions of respiratory system

\-Provide extensive surface area for gas exchange between air and blood

\-Move air to and from exchange surfaces on lungs

\-Protect resp. surfaces from dehydration, temp changes and pathogens

\-Produce sound

\-Detect odors

Upper resp. tract

nose, nasal cavity, paranasal sinuses and pharynx

Lower resp. tract

Larynx, trachea, bronchi, bronchioles and alveoli

Alveoli

Air filled pockets within lungs (where gas exchange occurs)

Resp. Mucosa

mucus membrane lining conducting portion of resp. tract (nasal cavity to larger bronchioles)

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Function:

\-Provides filtration that makes up resp, defense system

Components of resp. defense system

\-Filtration by nasal cavity removes large particles

\-Cilia sweep mucous and trapped debris to pharynx for swallowing

olfactory region

located in superior portion of nasal cavity

\-Provides sense of smell

meatuses

narrow passages which produce air turbulence to 1.) warm and humidify incoming air and 2.) bring to olfactory receptors

Lamina propria

underlying layer of areolar tissue that supports resp. epithelium

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Upper resp.: has mucous glands

Conducting portion of lower resp: smooth muscles

Pharynx

chamber shared by digestive and resp. systems (throat)

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Divided into three parts:

1\.)Nasopharynx (Superior, pharyngeal tonsils and auditory tube openings)

2\.)Oropharynx (connects directly to oral cavity)

3\.)Laryngopharynx (most inferior, between hyoid bone and entrance to larynx and esophagus

Glottis

slit-like opening between vocal cords (voice box) (where air enters the larynx)

Larynx

a cartilaginous tube that surrounds and protects the glottis

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Made of three unpaired cartilages:

\-Thyroid cartilage

\-Cricoid cartilage

\-epiglottis cartilage

epiglottis

structure which prevents food and liquids from entering resp. tract (folds over glottis)

how is sound produced?

air passing through open glottis vibrates vocal cords, producing sound waves

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\-pitch depends on diameter, tension and length of vocal folds

Trachea

a tough flexible tube that delivers/takes gases from lungs

\-Splits to form right and left main bronchi in mediastinum

tracheal cartilage

cartilages that make up the trachea (about 15-20)(stiffens windpipe and protects airway)

Function:

\-prevent collapse and overexpansion of due to pressure changes in resp. tract

Bronchial tree

Right and left main bronchi enter each of their respective lungs, and divide to form lobar bronchi

How many lobes in left and right human lungs (also differences between the two)

**Right lung:**

\-slightly larger (wider due to liver)

\-3 lobes (superior, middle and inferior)

\-3 lobar branches

\-10 bronchopulmonary

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Left lung:

\-Longer

\-two lobes (superior and inferior)

\-two lobar branches

\-8-9 bronchopulmonary

Division of lungs

Trachea→ main bronchus →lobar branches→ segmental bronchi→ bronchopulmonary segments (each segmental provides air to one bronchopulmonary segment)

bronchopulmonary segments

Branching of segmental bronchi form bronchioles

\-Bronchioles will than divide to form terminal bronchioles (finest conducting branches)

\-Terminal bronchioles branch to form respiratory bronchioles (connected to alveoli via alveolar ducts)

\-Alveolar ducts end in sac (common chambers for many individuals alveoli)

\*bronchioles kind of act like the arterioles of the resp. system

\*have no cartilage, dominated by smooth muscle

Alveolar cell layer

mainly composed of simple, squamous epithelium

\-pneumonocytes type 1: very thin and are sites of gas diffusion

\-Pneumonocytes type II: produce surfactant (oil secretions)(without things, surface tension would collapse the alveoli)

Bronchodilation

caused by sympathetic nervous system

\-enlarges diameter of luminal diameter of bronchioles

\-less resistance to flow

Bronchoconstriction

Caused by parasympathetic nervous system and histamine activation

\-reduced luminal diameter

\-more resistance to flow

blood air barrier

three layered barrier where gas exchange occurs in alveoli (The barrier between capillary blood and alveolar air)

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The 3 layers:

\-Alveolar cell layer

\-Capillary endothelial layer

\-Fused basement membrane between them

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\*very efficient because distance for diffusion is short and CO2/O2 are lipid soluble (can diffuse readily through surfactant & plasma membrane)

three layers that make up blood air barrier

\-Alveolar cell layer

\-Capillary endothelial layer

\-Fused basement membrane between them

Pneumonia

inflammation of lung tissue

pleural cavities

contains the left and right lungs

\-pleura is composed of a parietal pleura (lines outer surface of thoracic wall inner surface) and visceral pleura (covers surface of lungs)

\-Between the two layers is a space filled with pleural fluid

External respiration

all processes involved with exchange of O2 and CO2 with external environment (breathing)

Internal respiration

uptake of O2 and release of CO2 by cells (cellular respiration)

Pulmonary ventilation

physical movement of air into and out of resp. tract

Boyles law

Relationship between gas and pressure and volume

\-pressure of a gas increases when volume decreases

(increase V= Decrease P; Decrease V=Increase P)

pressure and airflow

Air flows from an area of higher pressure to an area of lower pressure