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KCUMB Histology > EXAM III Material > Flashcards

EXAM III Material Flashcards

1
Q

What are the different forms of immunity? (6)

A

Innate Immunity - inflammation, neutrophils

Acquired Immunity

Passive Immunity - temporary (transfer to fetus)

Active Immunity

Cell-mediated Immunity

Humoral Immunity

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2
Q

What are the primary lymphoid organs?

A

Thymus

Bone marrow

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3
Q

What are the secondary lymphoid organs?

A

Lymph Nodes

Spleen

Tonsils

Trapped Ag stimulate clonal expansions of mature T and B cells

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4
Q

Characteristics of Lymph follicles and types

A

Are not Enclosed within a capsule (Lymph Nodes ARE)

Singly or in aggregates

Sites of B cell localization & proliferation

Transient

Primary (unexposed) and Seconday (exposed) follicles

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5
Q

Characteristics of Primary follicles (nodules)

A

Spherical

Tightly packed accumulations of virgin B cells and dendritic reticular cells that haven’t been exposed to Ag

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6
Q

Characteristics of secondary follicles (nodules) and structure

A

Derived from primary follicles that have been exposed to foreign Ag

Not present at birth

Contain a Corona (cortex) - dark peripheral region, w/ densly packed B lymphocytes

and Germinal center - central, light, w/ B lymphocytes, memory B cells, plasma cells, dendritic reticular cells = Ag-presenting cells

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7
Q

Components of Diffuse lymphoid tissue

A

Subcutaneous-associated lymphoid tissue = papillary layer of dermis

Lamina propria-associated lymphoid tissue =

BALT - bronchial-associated lymphoid tissue

GALT - gut-associated lymphoid tissue

MALT - mucosal-associated lymphoid tissue

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8
Q

What is Lymphopoiesis?

A

Generation of lymphocytes

All originate in bone marrow

Immature T cells travel to thymus

B-cells travel to regions in lymphoid tissue

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9
Q

What are the surface receptors during maturation of B cells?

A

IgM and IgD

MHC Class II

Complement receptors

Ig Fc receptors

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10
Q

What is the function of MHC, where are they expressed and what recognizes them?

A

The presentation of (foreign) antigenic peptides of T cells

MHC I - surface of all cells except trophoblast & RBCs

via CD8+

MHC II - surface of B cells & Ag-presenting cells

via CD4+ on surface of APCs

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11
Q

Characteristics of CD4+ T cells

A

Recognize Ag on MHC II molecules

Helper Cells: assist CD8+ cell and B cell differentiation

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12
Q

Characteristics of CD8+ T cells

A

Cytolytic T cells; recognize Ag bound to MHC I molecules

Undergo mitosis

Release: perforins (punch holes in cells) and Fas ligand (signaling pathway for apoptosis of infected cells)

Mediators of cellular immunity

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13
Q

What are the characteristics of CD16+ T cells and what cytokines do they release? (5)

A

NK T cells

Interleukin-2 - stimulates NK cell proliferation

Interferon-ý - activates NK cells

Macrophage activating factor (MAF)

Chemotactic factors

Tumor necrosis factor (TNF-beta) - directly kills tumor cells

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14
Q

Define Parenchyma

A

Part of lymph node that contains cells that typically pack areas of lymphoid organ:

Mostly lymphocytes

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15
Q

Define Stroma

A

Part of lymph node that consists mainly of reticular fibers and cells; such as undifferentiated cells and fixed and free MOs

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16
Q

What are other histological structures of lymph nodes?

A

Hilus - entry & exit point for vessels (efferent enter thru hilus, afferent enter convex side)

Capsule - dense collagen fibers, some elastic fibers & smooth muscle fibers

Trabeculae - extensions of capsule

Cortex - (outer, follicles, deep/inner

Medulla

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17
Q

Components of Cortex of lymph nodes?

A

Outer - B cell zone - contains lymph follicles/nodules

Follicles - contain B cells, follicular & migrating dendritic cells

Secondary - mantle, germinal layer

Primary - lack both mantle and germinal layer

Deep/Inner Cortex - T cell zone -contains TH cells, MOs, High endothelial venules (HEVs) - port of entry for circulating differentiated lymphocytes to seed lymph node

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18
Q

What are the medulla characteristics of lymph nodes?

A

Irregular arrangment of loose medullary sinuses & dense medullary cords

(sinuses lined w/ MOs, cords contain blood vessels, lymphoblasts & plasma cells)

Site of lymphocyte reentry into lymph stream

Thymic-dependent areas in subcortical & deeper medullary regions

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19
Q

What are the components of the thymus?

A

Capsule

Trabeculae/Septa

Lobules

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20
Q

What are the characterisitcs of capsule of the thymus?

A

Contains blood vessels and efferent lymphatics

NO afferent lymphatics (lymph cells cannot enter via lymphatic system)

Extends trabeculae (septa) into the parenchyma

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21
Q

Characteristics of trabeculae (septa) of the thymus?

A

Contain delicate CT

Divides the thymus into incomplete lobules

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22
Q

Characteristics of Lobules of the Thymus?

A

Outer, Darker staining Cortex

Contains Epithelial reticular cells that secrete thymosin (a cytokine involved in early T cell differentiation & migrate to medullary areas) and T cells in various stages of diff., blood vessels for maintenance of lymphopoiesis

Inner, lighter staining Medulla

Allows entry channel into blood stream of mature lymphocytes

Hassall’s corpuscles - whorls of highly keratinized medullary epithelial cells that produce cytokine thymic stromal lymphopoietin = stimulates thymic dendritic cells needed for single (+) T cell maturation

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23
Q

Characteristics of the thymus? When are they fully developed? What is absent in their structure?

A

Most developed at puberty; 10-15g at birth, 30-40g at puberty

Involutes during adolescence

No lymph follicles (nodules; B cells)

No afferent lymph vessels

No lymph sinuses

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24
Q

What are the types of T cells involved during T cell differentiation?

A

Double (-) T cells - lack cell surface molecules, enter cortex from blood vessels, proliferate in subscapular area

Double (+) T cells - move to outer cortex, express CD4 & CD8 & TCR, interact w/ epithelial cells w/ MHC I & II for clonal selection,

Single (+) T cells - move to inner cortex, express TCR and EITHER CD4 or CD8

Medulla = clonal deletion completed (copies of T cells)

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25
Q

What is the blood-thymus barrier and where is it located?

A

Thymic cortex

Prevents Ag in the blood from reaching developing T cells in thymic cortex

Leaky during fetal life to allow for development of immunologic tolerance to self-Ag

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26
Q

Describe spleen morphology

A

No lymph sinuses

No afferent lymph vessels

Covered by peritoneum except at hilus

Blood vessels enter and exit hilus

Divided into red and white pulp

Mesothelium-lined CT capsule contains some smooth muscle fibers & sends trabeculae into parenchyma

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27
Q

What are the functions of the spleen?

A

Blood filtering functions:

Only lymphatic organ specialized to filter blood

Stores and removes worn out RBCs

Recycles iron

Converts Hb to bilirubin

in fetus = blood formation

Immunologic functions:

Screens foreign material in blood

Produces lymphocytes & plasma cells

Removal leads to overwhelming bacterial infections in infants, children, & young adults

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28
Q

Features of white pulp of the spleen

A

Elongated, branched strands, Associated with arteries, center & off center; germinal centers & diffuse lymphoid tissue

Site of clonal expansion of Ag-stimulated lymphocytes

Off center central arteriole of secondary follicles = B cell area

Center arteriole contains T cells = forms periarterial lymphatic sheath (PALS)

Reticular fibers w/ fixed MOs & support splenic pulp

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29
Q

Describe marginal zone histology of the spleen

A

Forms sinusoidal interface b/w red pulp and white pulp

Many Ag-presenting cells where lymphocytes have first Ag encounter and activated TH cells activate B cells

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30
Q

Describe red pulp histology of the spleen

A

Surrounds white pulp (majority of spleen; 80%)

Function = Filter blood (hence it’s red pulp)

Many RBCs

Billroth cords = red pulp parenchyma

w/ blood cells, plasma cells, Ag-presenting cells, Terminal capillaries open directly into substance of cords (open circulation), MO destroy worn-out, defective RBCs

Venous sinusoids - storage site for healthy RBCs, discontinuous basement membrane

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31
Q

What does the white pulp of the spleen consist of?

A

Central arteriole

PALS (pariarteriolar lymphoid sheath)

Corona formed by B & Ag-presenting cells

Germinal center

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32
Q

What is the red pulp formed by in the spleen?

A

Penicillar arteriole

MO-sheathed capillaries

Splenic sinusoids

Reticular cells = stroma (cords of Billroth)

all cell types of the circulating blood

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33
Q

Describe the characteristics of the tunica media

A

Components:

Smooth muscle cells and fibroblasts

Collagen and elastic fibers

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34
Q

Describe the characteristics of the tunica adventitia

A

NOT present in arterioles

Components:

Loose areolar tissue, irregular fibroelastic tissue w/ adipocytes, vasa vasorum and nervi vasorum (nerves)

Outermost layer

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35
Q

Define Pericytes

A

Undifferentiated mesenchymal cells

May be contractile, may serve as stem cells to differentiate into fibroblasts, etc.

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36
Q

List the general organization of the skin (5)

A

Epidermis

Basement Membrane

Dermis - (corresponds to lamina propria of a mucous membrane)

Subcutaneous/Hypodermis tissue

Epidermal ridges

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37
Q

What are the layers of the epidermal ridges and how are they formed? (4)

A

Primary dermal ridge - 3rd-4th months fetal life, subdivided into two secondary dermal ridges by interpapillary peg. Everywhere except foreheard, external ear, perineum & scrotum

Interpapillary peg - downward growth of epidermis along crest

Secondary dermal ridge - branched, double rows. Thin collagenous, reticular, and elastic fibers

Dermal papillae - upward projections from each secondary dermal ridge

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38
Q

List some of the integumentary functions

A

Protection from mechanical injury

Prevents dessicaiton

Protects against foreign substances & microorganims

Protects against UV radiation

Thermoregulation

Regulation of BP

Excretion of metabolic waste products

Synthesis of provitamin D

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39
Q

Is it possible for subcutaneous/hypodermis or dermis layer to have both thin and thick skin?

A

NO

Only epidermis contain thick and thin skin

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40
Q

Where is thick skin located

A

Palms & soles

~0.4-0.6 mm thick

Displays all 5 epidermal layers

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41
Q

Where is thin skin and what are some characteristics?

A

Located all over the body besides the palms & soles

~75-150 um thick

Thinnest = eyelids

Thickest = back

Thicker on extensor surfaces than flexor surfaces

Epidermal layers less distinct & lack stratum lucidum

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42
Q

List the layers of the epidermis from deep to outermost

A

BSGLC Big Skinned Girls Love Cheesecake

Stratum basale/germinativum

Stratum spinosum

Stratum granulosum

Stratum lucidum - absent in thin skin

Stratum corneum

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43
Q

Which epidermal layers are within the stratum Malpighi? (2)

A

Two deepest:

Stratum basale

Stratum spinosum

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44
Q

Which epidermal layer is absent in thin skin?

A

Stratum lucidum

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45
Q

What are Merkel cells?

What are the purpose of Merkel cells?

Primary locations?

A

Tactile mechanoreceptors

May also act as diffuse neuroendocrine cells

Usually in stratum germinativum/basale

Contain catecholamine-like granules

Palmar and plantar epidermis

Derived from neural crest

Associated with basal lamina

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46
Q

What is the purpose of Langerhans cells and where are the located?

A

Stratum of Malpighi (basale & spinosum)

Derived from bone marrow precursor

Peripheral dendritic cell of immune system = APCs in lymph node (migrate there)

Primarily in stratum spinosum

Dendritic cells

Birbeck granules

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47
Q

Where are melanocytes derived from and where are they located?

A

Neural crest; derived from melanoblasts

Does not form desmosomes attachments in epidermis

Inject melanin granules into keratinocytes

First cells to arrive in the epidermis

Cell body is in the stratum basale w/ cytoplasmic extensions on keratinocytes = epidermal-melanin unit

Melanin formation pathway requires Tyrosinase

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48
Q

What are the characteristics of stratum basale (germinativum)?

A

Deepest

Columnar to high cuboidal keratinocytes

Keratins 5 and 14 = major products of basal keratinocytes

Single layer of cells - held together via desmosomes, hemidesmosomes hold layer to basal lamina

High mitotic activity - producing stem cells differentiating keratinocytes, affected by chemotherapeutic & radiation treatments

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49
Q

What are the characteristics of the stratum spinosum

A

Polyhedral-shaped cells (prickle cells)

Keratins 1 and 10 (high molecular weight) replace 5 & 14 when basal keratinocytes migrate to spinosum

Keratohyalin granules develop

Contain primarily Langerhans cells

Membrane-coating granules first appear - lamellar bodies containing lipid, carbs, & hydrolytic enzymes

Tonofibrils - form intercellular bridges (adherin-type junctions)

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50
Q

What are the characteristics of stratum granulosum?

A

Multilayered

Keratins 2e and 9

Flattened nucleated keratinocytes

Keratohyalin aggregates - fillagrin (nonintermediate filament protein) induces cross-linkage of keratin filaments by disulfide bonds = keratin aggregation, no limiting membrane

Membrane-coating granules (lamellar bodies)

Tonofilaments

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51
Q

List characteristics of stratum lucidum

A

Clear layer/no detail

Flat keratinocytes lacking nuclei and organelles

Only found in thick skin

Contains eleiden

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52
Q

Which skin layer is only present in the thick skin?

A

Stratum lucidum

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53
Q

List characteristics of stratum cornuem

A

Multilayered

Thicker in thick skin

Enucleated, flattened, dead keratinocytes

Cytoplasm replaced by keratin

Cytoplasm contains: keratin cross-linked with filaggrin which produces cornified cell envelope

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54
Q

What are some characteristics of the dermis layer?

Derived from?

Function?

A

Dense fibrous irregular CT layer beneath epidermis

Derived from embryonic mesoderm

Induces development of epidermis and epidermal derivatives

Supports epidermis

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55
Q

Describe some hypodermis characteristics

A

Loose CT that underlies dermis

Corresponds to superficial fascia of gross anatomy

Technically not part of skin

May contain fat cells that can form a thick layer = panniculus adiposus

2 layers = papillary and reticular layer

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56
Q

What are the components of the two layers of the dermis?

A

Papillary layer (closest to epidermis)

Loose CT, separated from epidermis by basal lamina, network of fine elastic fibers and abundant capillaries

Reticular layer

Dense irregular CT

Fibrocytes, MOs, adipocytes

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57
Q

What is the role of IgA and where are they secreted from?

A

Produced by GALT (secretory IgA, sIgA)

Prevents microorganism binding to epithelium by coating microorganisms

Does not stimulate complement system

Synthesized & secreted by plasma cells in lamina propira of gut

Picked up at the basal surface of enterocytes & transported across the cell

secretory component inhibits degradation of sIgA by proteolytic enzymes in GI lumen while in the cell

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58
Q

List characteristics of acquired immunity

A

Develops in response to Ags

More powerful than innate immunity

Takes longer to develop

Displays specificity and memory

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59
Q

Where in the body do precursor cells mature into immunocompetent cells and are programmed to recognize a specific Ag?

A

In the primary lymph organs

i.e. thymus and bone marrow

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60
Q

Where in the body do trapped Ags stimulate clonal expansions of mature T and B cells?

A

Secondary lymphoid organs

i.e. spleen, lymph nodes, tonsils

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61
Q

Where in the body can you find B cells and dendritic reticular cells that have not been exposed to Ags?

A

Primary follicles/nodules

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62
Q

Where in the body can you find cells that have been exposed to nonself Ags? These are not present at birth

A

Secondary follicles/nodules

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63
Q

What are the components of the small intestine?

A

Duodenum

Jejunum

Ileum

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64
Q

What are the layers of the intestinal wall? (4)

A

M.S.M.S.

Mucosa w/ lamina propria and muscularis mucosa

Submucosa

Muscularis layers

Serosa

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65
Q

What are some characteristics of the duodenum?

A

Villi with a “leaflike” shape

Crypts of Lieberkuhn

Brunner’s glands (mucous-secreting) in the submucosa

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66
Q

What are some characteristics of the jejunum?

A

Finger-like villi; longer and more narrow

Crypts of Lieberkuhn

No glands in submucosa (as opposed to duodenum; Brunner’s glands)

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67
Q

What are some characteristics of the Ileum?

A

Shorter villi (compared with jejunum)

M cells (Ag-transporting cells; b/w villi in pits)

Peyer’s patches (lymphoid aggregates = large follicles) thruout lamina propria and submucosa

Crypts of Lieberkuhn

No glands in submucosa

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68
Q

What type of epithelium is within the large intestine?

A

Simple columnar with crypts but no villi

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69
Q

What are the cells of the crypts of Lieberkuhn? (4)

A

Enterocytes

Enteroendocrine cells

Goblet cells

Paneth cells

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70
Q

What are crypts of Lieberkuhn and where are they found?

A

Simple tubular glands within the intestinal mucosa of the duodenum and jejunum

Open b/w adjacent villi and extend to muscularis mucosa

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71
Q

What are enterocytes, where are they located and what is their function?

A

Located in the crypts of Lieberkuhn

Columnar epi. cells w/ a basal nucleus, perinuclear Golgi and apical brush border

Produce disaccharides, absorb proteins, carbs, lipids

Enzymes on apical brush border are involved in carb digestion

Produce enteropeptidase/enterokinase for activation of pancreatic zymogens & proenxymes

72
Q

What are Paneth cells, where are they located and what are their functions?

A

Cells of the crypts of Lieberkuhn

Basal crypt cells; found at base of mucosal glands

Prominent eosinophilic granules

Produce lysozyme to control intestinal flora; increases permeability of bacteria by degrading peptidoglycan

Defensins increase membrane permeability of target organisms

Tumor necrosis factor-alpha (proinflammatory cytokine)

May phagocytize some microorganisms and help regulate intestinal flora

73
Q

What are enteroendocrine cells, where are they located, and what is their funciton?

A

Cells of the crypts of Lierberkuhn

Produce peptide hormones & serotonin; may produce paracrine or autocrine secretions

Stain w/ chromiun/chromaffin; respond to silver stains = agyrophilic

Analogous to unicellular goblet cells

Formed from endodermal stem cells in GI tract

74
Q

What are Brunner Glands and where are they located? What is their function?

A

Glands in the submucosa of duodenum

Form bicarbonate and mucus which supplements bicarbonate from the pancreas

Necessary to neutralize gastric acid

75
Q

What are Peyer’s patches? Where are the located? What is their function?

A

Dome-shaped lymphoid structures under mucosal surface; Ileum

Contain HEVs = entrance of lymphocytes into lymphoid organs from bloodstream

Mucosal coverings contain M cells

Contain B- and T- cell dependent areas

76
Q

What are the functions of the large intestine? (5)

A

Absorption of fluid

Continuation of digestion initiated in small intestine

Formation of fecal mass

Goblet cell = prominent cell

Secretion of mucus for lubrication

77
Q

What is a major feature of the GI tract that provides a defense mechanism for the segments?

A

Epithelial cells are held together by occluding junctions held together via transmembrane proteins claudins and occludins

Function to prevent paracellular transport

Otherwise, Ag may reach the lamina propria

78
Q

What is rapid cell turnover and explain how it works in the esophagus & anus, small intestine, large intestine, and stomach

A

Protective mechanism by GI epithelium; lining replaced every 5 days

Esophagus & Anus - new cells in basal layer of stratified epithelium & migrate thru sub-basal levels to be sloughed off into lumen

Small Intestine - new cells formed in crypts from undifferentiated cells

Large Intestine - located at base of cypts due to no villi

Stomach - stem cells = neck of gastric glands

Differentiate into surface & neck mucus cells, enteroendocrine cells, parital cells, chief cells

79
Q

What are the cellular characteristics of Paneth cells?

A

Basophilic basal cytoplasm

Supranuclear Golgi complex

Large, intensely acidophilic apical secretory granules

80
Q

Describe the mucosal layer of the GI tract. Location? Secreted by? Made up of?

A

Coats intestinal epithelial luminal surface

Secreted by goblet cells

2 layers: Outer = microorganisms

Inner = antimicrobial proteins (from paneth cells, enterocytes, goblet cells) that resist microbial penetration

81
Q

What are toll-like receptors? What are their functions?

A

A type of pattern recognition receptor

Located on the surface of enterocytes

Recognize structurally conserved molecules that are broadly shared by pathogens, but they are distinguishable from host molecules

Pathogen associated molecular patterns (PAMPs)

Once Ag binds; B-cell is produced and matures into plasma cells then Abs in lamina propria

82
Q

What are M cells, what is their function?

A

Microfold cells

Involved in the initiation of the immune response

Take up Ag which bind to Ig receptors on lymphocytes surface, transferring them to dendritic cells; APCs (in the underlying lamina propria) = T cells

83
Q

What are GALTs? Where are they located and what are they composed of?

A

Gut-Associated Lymphoid Tissue

Appendix, Peyer’s patches, Mesenteric lymph nodes

Transitory aggregations of lymphocytes, neutrophils, and eosinophils

Bulk of body’s immune system located here

Produces IgA

84
Q

Where does carbohydrate digestion begin?

A

In the mouth via enzyme amylase

85
Q

What is the role of amylase?

A

Hydrolyzes starch to form sugars; disaccharides

Amylase is secreted via pancreas

86
Q

Where are disaccharides broken down to monosaccharides? Where are monosaccharides absorbed? How?

A

Brush border of small intestine

Monosaccharides absorbed via enterocytes via Na+-dependent sugar glucose transporter-1 (SGLT-1)

87
Q

What are the 3 events involved in protein digestion? What are the locations?

A

Proteins –> Peptides (stomach)

Polypeptides –> Peptides (small intestine)

Oligopeptides –> Amino Acids (Intestinal brush border)

88
Q

What enzyme is involved in protein digestion in the mouth?

A

Pepsine

In the stomach’s acidic environment

89
Q

What enzyme(s) are involved in protein digestion in the stomach (4)? What is happening? Where?

A

Breakdown of polypeptides –> proteins (small intestine)

Pancreatic Enzymes: (4)

Trypsin

Chymotrypsin

Elastase

Carboxypeptidase

90
Q

What enzyme activates pancreatic enzymes that are involved in the breakdown of polypeptides to peptides in the small intestine?

A

Enteropeptidase/Enterokinase

via duodenal enterocytes

91
Q

Where does the breakdown of oligopeptides to amino acids occur?

A

Bursh border of the intestine

The transport of aa into enterocytes is via a carrier-mediated process

92
Q

Where does lipid digestion begin?

A

Small intestine

93
Q

What is the role of pancreatic lipase in lipid digestion?

A

Emulsifies triglyceride droplets that enter the small intestine into smaller droplets releasing FAs and glycerol

FAs and glycerol combine with bile salts to form micelles

94
Q

What is a micelle and what is its role in lipid digestion?

A

Micelles arise from glycerol and FAs that combine with bile salts

Micelles transport:

FAs

Monoglycerides

Glycerol

Phospholipids

Cholesterol

Vit A and K

Micelles are passively absorbed across enterocyte apical plasma membrane via FABPs (FA Binding protein)

95
Q

What is the role of pancreatic lipid esterase?

A

Splits cholesterol esters into cholesterol and FAs

96
Q

What are the steps necessary during differentiation of T cells? (4)

A

Double negative

Double positive

Single positive

Clonal deletion

97
Q

What are the characteristics of double negative T cells? Where are they located?

A

Lack cell surface molecules (in mature T cells)

Proliferate in subcapsular area (outside cortex)

Enter cortex from blood vessels

98
Q

What are the characteristics of double positive T cells and what do they express?

A

Express both CD4 & CD8 coreceptors and TCR receptors

Are deeper in cortex

Confronted with epithelial cells w/ cell surface MHC classes I and II for clonal selection

99
Q

What do single positive T cells express?

A

Either CD4 or CD8 and TCR receptors

Mature T cells

100
Q

Where does clonal deletion of T cells occur?

A

Medulla

101
Q

What are the components of the blood thymic barrier? (6)

A

Endothelium

Endothelial basal lamina

Perivascular space

Reticular cells

Basal lamina of reticular cells

Thymic parenchymal cells

102
Q

What are the blood filtering functions of the spleen?

A

Blood filtering functions:

Only lymphatic organ specialized to filter blood

Stores and removes worn out RBCs

Recycles iron

Converts Hb to bilirubin

in fetus = blood formation

103
Q

What are the immunologic functions of the spleen?

A

Immunologic functions:

Screens foreign material in blood

Produces lymphocytes & plasma cells

Removal leads to overwhelming bacterial infections in infants, children, & young adults

104
Q

What occurs in the white pulp of the spleen?

A

Clonal expansion of Ag-stimulated lymphocytes

105
Q

What forms the periarterial lymphatic sheath (PALS) of the spleen?

A

T cells that are contained in the areas surrounding the central artery near the center of the white pulp

106
Q

What is the function of the marginal zone of the spleen?

A

Forms sinusoidal interface between red pulp and white pulp

The site of initial Ag exposure to lymphocytes

107
Q

Which gland cells are stimulated at puberty?

A

Sebaceous glands

Sudoriferous/sweat Apocrine glands

108
Q

What is the function of the red pulp of the spleen?

A

Filters blood

109
Q

What are the 3 arteries of the spleen?

A

Splenic artery - enters hilus

Trabecular artery - branches off

Central artery - where adventitia loosens and becomes mesh-like reticulum infiltrated with lymphocytes. A penicillus is formed when capillaries enter red pulp

Cappillaries - supply white pulp

110
Q

What are the components of the penicillus of the spleen?

A

Pulp arteriole

Sheathed arteriole

Terminal capillary - drains into intercellular/open spaces or venous sinuses lined w/ reticuloendothelial cells/closed system

111
Q

What are Langerhan cells?

Were are the derived from and what are their functions?

A

Dendritic cells; via monocytes

Ag-presenting cells (APC cells)

Primarily in stratum spinosum; migrate from epidermis to lymph nodes

Birbeck granules

112
Q

List the cells of the skin (4)

A

Keratinocytes

Langerhans cells

Merkel cells

Melanocytes

113
Q

What type of glands are sebaceous glands? (Apocrine, Holocrine, Merocrine, etc.)

A

Holocrine glands

Secretions are released by destroying cell membrane of sebum-producing cells

114
Q

Where are sebaceous glands found on the body?

A

Everywhere besides palms and soles of the feet

115
Q

What is the structure of sebaceous glands and what do they produce? When is the growth of these glands stimulated?

A

Branched acinar glands w/ short ducts

Produce sebum continuously; released into hair follicle

Growth stimulated at puberty by sex hormones

116
Q

What are sudoriferous glands? What type of glands are they?

A

Sweat glands

Merocrine glands & Apocrine glands

117
Q

What are characteristics of sudoriferous glands?

A

(sweat glands)

Duct system with stratified cuboidal epithelium except in epidermis

Cholinergic endings; stimulated by ACh

118
Q

What are characteristics of merocrine glands (apart of sudoriferous glands)

A

Coiled, simple tubular secretory portions

Lined by simple epithelium

Apical dark secretory cells secrete glycoproteins

Basal clear cells secrete water and electrolytes

Myoepithelial cells

119
Q

What are characteristics of apocrine glands (apart of sudoriferous glands)?

Location?

Structure?

A

Found in labia majora, areola, axillary & anal regions

Thicker, more viscous secretions than merocrine types

Excretory duct opens into hair follicle

Adrenergic innervation

Inactive until pubery

Special types; ceruminous glands, glands of moll

120
Q

What are the special types of apocrine glands of the sudoriferous glands?

A

Ceruminous glands (ear canal, ear wax)

Gands of Moll (eyelids; keeping them from sticking together)

121
Q

What are the components of the hair follicle?

A

Root (the growing part of the hair)

Free shaft

Hair follicle

122
Q

Which embryonic layer is the hair follicle derived from?

A

Epidermis

Developed as elastic, keratinized threads

123
Q

What are the components of the hair follicle? (3)

A

Sebaceous glands, arrector mili muscles

Hair bulb

External root sheath - down growth of epidermis

Internal root sheath - generated by bulb matrix

124
Q

What are the 2 components of the hair bulb and where is it in relation to the hair follicle?

A

Matrix and vascularized dermal papilla

Located at the lower part of the hair follicle

125
Q

What are the layers of the internal root sheath of the hair follicle? CHH

A

CHH

Cuticle - interlocks w/ cuticle of hair shaft

Henle’s layer (outermost)

Huxley’s layer

126
Q

What are the layers of the hair shaft?

A

Medulla (innermost)

Cortex

Cuticle (outermost)

127
Q

What is a unique feature of keratinocyte stem cells?

A

Can reestablish epidermis in severely burned patients

Have a migration and signaling pathway

128
Q

What are the migration pathway of keratinocyte stem cells? (3)

A

Bulb-epidermis stem cell pathway

Bulb-hair stem cell pathway

Bulb-sebaceous gland stem cell pathway

129
Q

What are the signaling pathways of keratinocyte stem cells? (2)

A

Wnt signaling pathway

Notch signaling pathway

130
Q

What are Meissner’s Corpuscle? What is their function?

A

(Tactile corpuscle)

Type of mechanoreceptor

Type of nerve ending in the skin responsible for sensitivity to light touch

131
Q

What are Pacini Corpuscles

A

One of the 4 major types of mechanoreceptors

Nerve endings in skin responsible for sensitivity to vibration and pressure

132
Q

What 3 layers are the walls of blood vessels (except capillaries) characterized by?

A

Tunica intima

Tunica media

Tunica adventitia

133
Q

What are the components of the respiratory mucosa? (3)

A

Respiratory epithelium = pseudostratified cilitated columnar epithelium (lines most conducting structures)

Lamina propria/basement membrane - thin layers of CT

Submucosa - dense irregular CT

134
Q

What are the components of the respiratory system? (6)

A

Nose and Olfactory mucosa

Paranasal sinuses

Pharynx (opening of pharynx into esophagus)

Larynx

Trachea

Lung

135
Q

What type of epithelium lines the nares?

A

Stratified squamous epithelium continuous w/ epidermis with sebaceous glands and hair follicles

Mucosa at nasal septum:

pseudostratified ciliated columnar = respiratory epithelium

Basement membrane

Lamina propria

136
Q

What type of epithelium is respiratory epithelium?

A

Pseudostratified ciliated columnar epithelium

137
Q

Where is olfactory epithelium located? What is the epithlium type and what feature do they not possess?

A

Nasal cavity of roof

Pseudostratified columnar epithelium w/out goblet cells

No distinct basement membrane

138
Q

What are the cell types of olfactory epithelium? (4)

A

Basal cells w/ pigment granules

Olfactory cells

Olfactory glands of Bowman

Sustentacular cells (pigment cells) w/ pigment granules

139
Q

What are basal cells (with pigment granules) of the olfactory epithelium?

A

Stem cells that give rise to immature olfactory cells

140
Q

What are olfactory cells? Describe the characteristics of apical and basal ends

A

Bipolar neurons

Cilia contain GPCR odor-specific receptors

Apical end = projects into nasal cavity as knoblike ending w/ nonmotile cilia

Basal end = extends as an unmyelinated axon, bundled w/ other similar axons, thru ethmoid plate to mitral cells in olfactory bulb

Get replaced by basal cells when old (senesce)

141
Q

What are the functions of Olfactory glands of Bowman? Where are they located?

A

Lamina propria (CT layer)

Secrete odorant-binding protein which binds to odorant molecule in nasal cavity

142
Q

What are the steps that occur in generating an action potential in olfactory cells?

A

Odorant-binding protein + odorant molecule

binds odorant receptor protein (G protein) on olfactory cell cilium

Activates Adenyl Cyclase

ATP –> cAMP –> Na+ channels open –> AP

143
Q

What are the 3 structures of the nasopharynx? Explain their characteristics

A

Mucosa - respiratory epithelium, lamina propria w/ FECT, mucous glands, serous & mixed glands, diffuse lymphatic tissue

Submucosa - loose CT, MALT

Waldeyer’s ring - ring of lymphoid tissue around nasopharynx, tonsils and adenoids

144
Q

What are the characteristics of mucosa of the nasopharynx?

A

Respiratory epithelium - pseudostratified ciliated w/ goblet cells

Lamina propria with FECT, mucous glands, serous and mixed glands, and diffuse lymphatic tissue

145
Q

What are characteristics of the submucosa of the nasopharynx?

A

Loose CT

MALT

146
Q

What are Waldeyer’s ring? Where are they located in the nasopharynx?

A

Ring of lymphoid tissue around the nasopharynx

Tonsils and adenoids

147
Q

What are the two major components of the larynx?

A

Epiglottis

Vestibular folds (false vocal cords)

True vocal cords

148
Q

What are the 3 general structures of the epiglottis? What type of epithelium do they contain? What’s the lamina propria made up of? LPC

A

Lingual surface (faces back of tongue)

Stratified squamous epithelium

Lamina propria w/ loose CT & elastic fibers

Pharyngeal surface (faces pharynx)

Pseudostratified ciliated epithelium

Lamina propria = tubuloacina seromucous glands

Core of epiglottis consists of elastic cartilage

149
Q

What type of epithelium is contained with the vestibular folds? Lamina propria?

A

False vocal cords

Pseudostratified ciliated epithelium

Lamina = seromucous glands

150
Q

What is the general histology of intrapulmonary bronchi?

A

(beyond primary bronchi)

Mucosa - similar to trachea & extrapulmonary bronchi, elastic fibers and mucosal folds (smooth muscle)

Submucosa - loose CT, lymphatic tissue, mixed and mucous glands

Adventitia - hyaline cartilage plates w/ dense FECT

151
Q

What type of epithelium is within the true vocal cords of the larynx?

A

Stratified squamous epithelium (resists abrasion)

lack seromucous glands in lamina propria

Remainder of larynx covered w/ pseudostratified ciliated epithelium

152
Q

What types of cartilage and muscle are within the larynx?

A

Elastic and Hyaline cartilage

Skeletal muscle

153
Q

What 2 locations in the larynx contain stratified squamous epithelium?

A

Lingual surface of the epiglottis

True vocal cords

The rest contain pseudostratified ciliated columnar

154
Q

What are the 3 components of the trachea?

A

Mucosa

Submucosa

Adventitia

155
Q

What are the characteristics of the mucosa and submucosa of the trachea?

A

Mucosa - respiratory epithelium w/ thick basement membrane

Lamina propria = delicate FECT & lymphatic tissue

Submucosa - sero-mucous glands

156
Q

Describe the adventitia of the trachea

A

Cartilages that surround the trachea

16-20 horseshoe-shaped cartilages interconnected via FECT

Faced posteriorly, contain FECT, mucous membrane and smooth muscle/trachealis muscles

Mixed glands and capillaries

Become circular once in bronchi

157
Q

What are the extrapulmonary components of the lungs?

A

Left and Right Primary Bronchi

From trachea –> primary bronchi; replacement of hyaline cartilage rings by irregularly shaped cartilaginous plates

158
Q

List the general structure of the lungs from trachea to alveoli

A

Trachea

Primary Bronchi

Secondary Bronchi/Segmental

Tertiary Bronchi

Bronchioles

Terminal Bronchioles

Respiratory Bronchioles

Alveolar Sac

159
Q

Which lung structure begins the intrapulmonary segments?

A

Segmental/Secondary Bronchi

Contain circular rings w/ hyaline cartilage that transition to irregular plates

160
Q

What are characteristics of the bronchioles?

A

No Cartilage

No glands

Few goblet cells

Large amount of smooth muscle

Epithelium = ciliated columnar w/ few goblet cells –> ciliated cuboidal w/ no goblet cells (terminal bronchioles)

Terminal bronchioles –> Respiratory bronchioles

161
Q

Where in the lung does gas exchange start at?

A

Respiratory bronchioles

After the terminating bronchioles

162
Q

What are the characteristics of respiratory bronchioles?

A

Low columnar –> low cuboidal

Cilia in larger respiratory bronchioles

No goblet cells

Walls contain smooth muscle within FECT

Few alveolar outpocketings

163
Q

Characteristics of Alveolar ducts?

A

Continuations of respiratory bronchioles

Cone-shaped

Squamous epithelium

Wall = smooth muscle w/ FECT

Alveolar sac = several alveoli

164
Q

Define Type I alveolar cells/Type I Pneumocytes

A

Less numerous than Type II

Cover largest suface area (more thinner)

165
Q

Define Type II Alveolar Cells/Pneumocytes

A

Produce surfactant

Cuboidal/rounded

Stem cells for Type I and Type II

166
Q

Define Pores of Kohn

A

Openings between adjacent alveoli

Allows for alternate pathways for air from one alveoli to the next

167
Q

What are the cell types of the mucosa of the respiratory system?

A

Ciliated columnar

Nonciliated columnar

Stem Cells

Goblet Cells - mucous secreting; stem cells

Neuroendocrine cells/Small granule cells

168
Q

What are the general characteristics of ciliated/nonciliated columnar cells and stem cells?

A

Nonciliated - contain microvilli, no cilia

Stem cells - basal cells of pseudostratified epithelium, self-replace

169
Q

What is the function of neuroendocrine cells of the respiratory system?

A

Release catecholamines

More prevalent in infants; sensory reception(?)

170
Q

What two cells secrete surfactant?

A

Clara and Type II Alveolar/Pneumocytes

171
Q

Characteristics of Type II Alveolar cells

A

​Lamellar bodies​ = Distinctive under EM; contain lecithin

Phagocytize old surfactant; more round

Can divide and replace Type I

Secreted from apical domain of cells

Combine w/ proteins from Clara cells

Produce phospholipid-protein surfactant that coats alveolar walls

172
Q

Characteristics of Type I Alveolar/Pneumocytes

A

Thin cytoplasm

covers 95% of alveolar surface

Basal lamina may be fused with basal lamina of nearby capillaries

173
Q

Define Clara cells, where are they found

A

Secrete surfactant & lipoprotein that prevents collapse of terminal bronchioles during exhalation

Bronchioles

Identified by apical surface that bulges into lumen of airway

Abundant SER; greater # with less ciliated columnar cells

174
Q

What are dust cells and what are their roles?

A

Macrophages; derived from monocytes

Phagocytize pollutants, bacteria, surfactant

175
Q

What relation does dust cells have with congestive heart failure?

A

Generate heart failure cells (iron-containing dust cells) due to dust cells phagocytizing fluid that contains breakdown products of Hb that leaks into alveolar spaces

176
Q

What are the 3 components of the air-blood respiratory barrier? What is its characteristic?

A

Thin capillary endothelium

Thin epithelium of pneumocyte

Intervening basal lamina produced by Type I and Type II

Permits gas exchange but doesn’t allow fluids or cells to enter alveoli

177
Q

What is the most important opsonin?

A

C3b

KCUMB Histology (13 decks)

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