EXAM III Material Flashcards
(177 cards)
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
2
Q
What are the primary lymphoid organs?
A
Thymus
Bone marrow
3
Q
What are the secondary lymphoid organs?
A
Lymph Nodes
Spleen
Tonsils
Trapped Ag stimulate clonal expansions of mature T and B cells
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
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
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
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
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
9
Q
What are the surface receptors during maturation of B cells?
A
IgM and IgD
MHC Class II
Complement receptors
Ig Fc receptors
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
11
Q
Characteristics of CD4+ T cells
A
Recognize Ag on MHC II molecules
Helper Cells: assist CD8+ cell and B cell differentiation
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
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
14
Q
Define Parenchyma
A
Part of lymph node that contains cells that typically pack areas of lymphoid organ:
Mostly lymphocytes
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
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
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
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
19
Q
What are the components of the thymus?
A
Capsule
Trabeculae/Septa
Lobules
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
21
Q
Characteristics of trabeculae (septa) of the thymus?
A
Contain delicate CT
Divides the thymus into incomplete lobules
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
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
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)
25
What is the blood-thymus barrier and where is it located?
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
26
Describe spleen morphology
**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
27
What are the functions of the spleen?
**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
28
Features of white pulp of the spleen
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
29
Describe marginal zone histology of the spleen
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
30
Describe red pulp histology of the spleen
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
31
What does the white pulp of the spleen consist of?
**Central arteriole**
**PALS (pariarteriolar lymphoid sheath)**
**Corona** formed by B & Ag-presenting cells
**Germinal center**
32
What is the red pulp formed by in the spleen?
**Penicillar arteriole**
**MO-sheathed capillaries**
**Splenic sinusoids**
**Reticular cells = stroma** (cords of Billroth)
**all cell types of the circulating blood**
33
Describe the characteristics of the tunica media
Components:
## Footnote
**Smooth muscle cells and fibroblasts**
**Collagen and elastic fibers**
34
Describe the characteristics of the tunica adventitia
**_NOT present in arterioles_**
Components:
**Loose areolar tissue, irregular fibroelastic tissue w/ adipocytes, vasa vasorum and nervi vasorum** (nerves)
Outermost layer
35
Define Pericytes
Undifferentiated **mesenchymal cells**
May be contractile, may serve as stem cells to differentiate into fibroblasts, etc.
36
List the general organization of the skin (5)
**Epidermis**
**Basement Membrane**
**Dermis** - (corresponds to lamina propria of a mucous membrane)
**Subcutaneous/Hypodermis tissue**
**Epidermal ridges**
37
What are the layers of the epidermal ridges and how are they formed? (4)
**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
38
List some of the integumentary functions
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
39
Is it possible for subcutaneous/hypodermis or dermis layer to have both thin and thick skin?
NO
Only epidermis contain thick and thin skin
40
Where is thick skin located
**Palms & soles**
**~0.4-0.6 mm thick**
**Displays all 5 epidermal layers**
41
Where is thin skin and what are some characteristics?
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
42
List the layers of the epidermis from deep to outermost
**BSGLC** Big Skinned Girls Love Cheesecake
Stratum **basale/germinativum**
Stratum **spinosum**
Stratum **granulosum**
Stratum **lucidum** - absent in thin skin
Stratum **corneum**
43
Which epidermal layers are within the stratum Malpighi? (2)
Two deepest:
## Footnote
**Stratum basale**
**Stratum spinosum**
44
Which epidermal layer is absent in thin skin?
**Stratum lucidum**
45
What are Merkel cells?
What are the purpose of Merkel cells?
Primary locations?
**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
46
What is the purpose of Langerhans cells and where are the located?
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**
47
Where are melanocytes derived from and where are they located?
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**
48
What are the characteristics of stratum basale (germinativum)?
**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
49
What are the characteristics of the stratum spinosum
**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)
50
What are the characteristics of stratum granulosum?
**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**
51
List characteristics of stratum lucidum
Clear layer/no detail
## Footnote
**Flat keratinocytes lacking nuclei and organelles**
**Only found in thick skin**
**Contains eleiden**
52
Which skin layer is only present in the thick skin?
**Stratum lucidum**
53
List characteristics of stratum cornuem
**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
54
What are some characteristics of the dermis layer?
Derived from?
Function?
**Dense fibrous irregular CT layer beneath epidermis**
**Derived from embryonic mesoderm**
**Induces development of epidermis and epidermal derivatives**
**Supports epidermis**
55
Describe some hypodermis characteristics
**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**
56
What are the components of the two layers of the dermis?
**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
57
What is the role of IgA and where are they secreted from?
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**
58
List characteristics of acquired immunity
Develops in response to Ags
More powerful than innate immunity
Takes longer to develop
Displays **specificity and memory**
59
Where in the body do precursor cells mature into immunocompetent cells and are programmed to recognize a specific Ag?
In the **primary lymph organs**
## Footnote
**i.e. thymus and bone marrow**
60
Where in the body do trapped Ags stimulate clonal expansions of mature T and B cells?
**Secondary lymphoid organs**
**i.e. spleen, lymph nodes, tonsils**
61
Where in the body can you find B cells and dendritic reticular cells that have not been exposed to Ags?
**Primary follicles/nodules**
62
Where in the body can you find cells that have been exposed to nonself Ags? These are not present at birth
**Secondary follicles/nodules**
63
What are the components of the small intestine?
Duodenum
Jejunum
Ileum
64
What are the layers of the intestinal wall? (4)
M.S.M.S.
Mucosa w/ lamina propria and muscularis mucosa
Submucosa
Muscularis layers
Serosa
65
What are some characteristics of the duodenum?
Villi with a "leaflike" shape
**Crypts of Lieberkuhn**
**Brunner's glands** (mucous-secreting) in the submucosa
66
What are some characteristics of the jejunum?
**Finger-like villi; longer and more narrow**
**Crypts of Lieberkuhn**
**No glands in submucosa** (as opposed to duodenum; Brunner's glands)
67
What are some characteristics of the Ileum?
**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**
68
What type of epithelium is within the large intestine?
Simple columnar with crypts but no villi
69
What are the cells of the crypts of Lieberkuhn? (4)
**Enterocytes**
**Enteroendocrine cells**
**Goblet cells**
**Paneth cells**
70
What are crypts of Lieberkuhn and where are they found?
Simple tubular glands within the intestinal mucosa of the duodenum and jejunum
Open b/w adjacent villi and extend to muscularis mucosa
71
What are enterocytes, where are they located and what is their function?
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
What are Paneth cells, where are they located and what are their functions?
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
What are enteroendocrine cells, where are they located, and what is their funciton?
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
What are Brunner Glands and where are they located? What is their function?
Glands in the **submucosa of duodenum**
**Form bicarbonate and mucus** which supplements bicarbonate from the pancreas
Necessary to neutralize gastric acid
75
What are Peyer's patches? Where are the located? What is their function?
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
What are the functions of the large intestine? (5)
Absorption of fluid
Continuation of digestion initiated in small intestine
Formation of fecal mass
Goblet cell = prominent cell
Secretion of mucus for lubrication
77
What is a major feature of the GI tract that provides a defense mechanism for the segments?
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
What is rapid cell turnover and explain how it works in the esophagus & anus, small intestine, large intestine, and stomach
**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
What are the cellular characteristics of Paneth cells?
Basophilic basal cytoplasm
Supranuclear Golgi complex
Large, intensely acidophilic apical secretory granules
80
Describe the mucosal layer of the GI tract. Location? Secreted by? Made up of?
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
What are toll-like receptors? What are their functions?
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
What are M cells, what is their function?
**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
What are GALTs? Where are they located and what are they composed of?
**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
Where does carbohydrate digestion begin?
In the **mouth** via enzyme **amylase**
85
What is the role of amylase?
**Hydrolyzes starch** to form sugars; **disaccharides**
Amylase is secreted via **pancreas**
86
Where are disaccharides broken down to monosaccharides? Where are monosaccharides absorbed? How?
**Brush border of small intestine**
Monosaccharides absorbed via **enterocytes** via **Na+-dependent sugar glucose transporter-1 (SGLT-1)**
87
What are the 3 events involved in protein digestion? What are the locations?
Proteins --\> Peptides (stomach)
Polypeptides --\> Peptides (small intestine)
Oligopeptides --\> Amino Acids (Intestinal brush border)
88
What enzyme is involved in protein digestion in the mouth?
**Pepsine**
In the stomach's **acidic** environment
89
What enzyme(s) are involved in protein digestion in the stomach (4)? What is happening? Where?
Breakdown of **polypeptides --\> proteins** (small intestine)
**Pancreatic Enzymes:** (4)
**Trypsin**
**Chymotrypsin**
**Elastase**
**Carboxypeptidase**
90
What enzyme activates pancreatic enzymes that are involved in the breakdown of polypeptides to peptides in the small intestine?
**Enteropeptidase/Enterokinase**
via duodenal enterocytes
91
Where does the breakdown of oligopeptides to amino acids occur?
**Bursh border of the intestine**
The transport of aa into enterocytes is via a carrier-mediated process
92
Where does lipid digestion begin?
**Small intestine**
93
What is the role of pancreatic lipase in lipid digestion?
**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
What is a micelle and what is its role in lipid digestion?
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
What is the role of pancreatic lipid esterase?
Splits cholesterol esters into **cholesterol and FAs**
96
What are the steps necessary during differentiation of T cells? (4)
Double negative
Double positive
Single positive
Clonal deletion
97
What are the characteristics of double negative T cells? Where are they located?
Lack cell surface molecules (in mature T cells)
Proliferate in subcapsular area (outside cortex)
**Enter cortex from blood vessels**
98
What are the characteristics of double positive T cells and what do they express?
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
What do single positive T cells express?
**Either CD4 or CD8** **and TCR receptors**
## Footnote
**Mature T cells**
100
Where does clonal deletion of T cells occur?
Medulla
101
What are the components of the blood thymic barrier? (6)
Endothelium
Endothelial basal lamina
Perivascular space
Reticular cells
Basal lamina of reticular cells
Thymic parenchymal cells
102
What are the blood filtering functions of the spleen?
**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
What are the immunologic functions of the spleen?
**Immunologic functions:**
Screens foreign material in blood
Produces lymphocytes & plasma cells
Removal leads to overwhelming bacterial infections in infants, children, & young adults
104
What occurs in the white pulp of the spleen?
Clonal expansion of Ag-stimulated lymphocytes
105
What forms the periarterial lymphatic sheath (PALS) of the spleen?
T cells that are contained in the areas surrounding the central artery near the center of the white pulp
106
What is the function of the marginal zone of the spleen?
Forms sinusoidal interface between red pulp and white pulp
The site of **initial Ag exposure** to lymphocytes
107
Which gland cells are stimulated at puberty?
**Sebaceous** **glands**
## Footnote
**Sudoriferous/sweat Apocrine glands**
108
What is the function of the red pulp of the spleen?
Filters blood
109
What are the 3 arteries of the spleen?
**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
What are the components of the penicillus of the spleen?
Pulp arteriole
Sheathed arteriole
Terminal capillary - drains into intercellular/open spaces or venous sinuses lined w/ reticuloendothelial cells/closed system
111
What are Langerhan cells?
Were are the derived from and what are their functions?
**Dendritic cells**; via monocytes
**Ag-presenting cells** (APC cells)
Primarily in stratum spinosum; migrate from epidermis to lymph nodes
Birbeck granules
112
List the cells of the skin (4)
Keratinocytes
Langerhans cells
Merkel cells
Melanocytes
113
What type of glands are sebaceous glands? (Apocrine, Holocrine, Merocrine, etc.)
Holocrine glands
Secretions are released by destroying cell membrane of sebum-producing cells
114
Where are sebaceous glands found on the body?
Everywhere besides palms and soles of the feet
115
What is the structure of sebaceous glands and what do they produce? When is the growth of these glands stimulated?
**Branched acinar glands w/ short ducts**
Produce **sebum** continuously; released into hair follicle
Growth stimulated at **puberty** by sex hormones
116
What are sudoriferous glands? What type of glands are they?
Sweat glands
## Footnote
**Merocrine glands & Apocrine glands**
117
What are characteristics of sudoriferous glands?
(sweat glands)
Duct system with **stratified cuboidal epithelium except in epidermis**
**Cholinergic endings**; stimulated by ACh
118
What are characteristics of merocrine glands (apart of sudoriferous glands)
**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
What are characteristics of apocrine glands (apart of sudoriferous glands)?
Location?
Structure?
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
What are the special types of apocrine glands of the sudoriferous glands?
**Ceruminous glands** (ear canal, ear wax)
**Gands of Moll** (eyelids; keeping them from sticking together)
121
What are the components of the hair follicle?
**Root** (the growing part of the hair)
**Free shaft**
**Hair follicle**
122
Which embryonic layer is the hair follicle derived from?
**Epidermis**
Developed as elastic, keratinized threads
123
What are the components of the hair follicle? (3)
Sebaceous glands, arrector mili muscles
Hair bulb
External root sheath - **down growth of epidermis**
Internal root sheath - **generated by bulb matrix**
124
What are the 2 components of the hair bulb and where is it in relation to the hair follicle?
**Matrix and vascularized dermal papilla**
Located at the lower part of the hair follicle
125
What are the layers of the internal root sheath of the hair follicle? CHH
**CHH**
**Cuticle** - interlocks w/ cuticle of hair shaft
**Henle's layer** (outermost)
**Huxley's layer**
126
What are the layers of the hair shaft?
**Medulla** (innermost)
**Cortex**
**Cuticle** (outermost)
127
What is a unique feature of keratinocyte stem cells?
Can reestablish epidermis in severely burned patients
Have a **migration** and **signaling** pathway
128
What are the migration pathway of keratinocyte stem cells? (3)
**Bulb-epidermis stem cell pathway**
**Bulb-hair stem cell pathway**
**Bulb-sebaceous gland stem cell pathway**
129
What are the signaling pathways of keratinocyte stem cells? (2)
**Wnt signaling pathway**
**Notch signaling pathway**
130
What are Meissner's Corpuscle? What is their function?
(Tactile corpuscle)
Type of mechanoreceptor
Type of **nerve ending** in the skin responsible for sensitivity to light touch
131
What are Pacini Corpuscles
One of the 4 major types of mechanoreceptors
**Nerve endings** in skin responsible for **sensitivity to vibration and pressure**
132
What 3 layers are the walls of blood vessels (except capillaries) characterized by?
**Tunica intima**
**Tunica media**
**Tunica adventitia**
133
What are the components of the respiratory mucosa? (3)
Respiratory epithelium = **pseudostratified cilitated columnar epithelium** (lines most conducting structures)
**Lamina propria/basement membrane** - thin layers of CT
**Submucosa** - dense irregular CT
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What are the components of the respiratory system? (6)
Nose and Olfactory mucosa
Paranasal sinuses
Pharynx (opening of pharynx into esophagus)
Larynx
Trachea
Lung
135
What type of epithelium lines the nares?
**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
What type of epithelium is respiratory epithelium?
**Pseudostratified ciliated columnar epithelium**
137
Where is olfactory epithelium located? What is the epithlium type and what feature do they not possess?
Nasal cavity of roof
**Pseudostratified columnar epithelium w/out goblet cells**
No distinct basement membrane
138
What are the cell types of olfactory epithelium? (4)
**Basal cells w/ pigment granules**
**Olfactory cells**
**Olfactory glands of Bowman**
**Sustentacular cells** (pigment cells) **w/ pigment granules**
139
What are basal cells (with pigment granules) of the olfactory epithelium?
Stem cells that give rise to immature olfactory cells
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What are olfactory cells? Describe the characteristics of apical and basal ends
**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
What are the functions of Olfactory glands of Bowman? Where are they located?
**Lamina propria** (CT layer)
**Secrete odorant-binding protein** which binds to **odorant molecule in nasal cavity**
142
What are the steps that occur in generating an action potential in olfactory cells?
**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
What are the 3 structures of the nasopharynx? Explain their characteristics
**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
What are the characteristics of mucosa of the nasopharynx?
Respiratory epithelium - pseudostratified ciliated w/ goblet cells
Lamina propria with FECT, mucous glands, serous and mixed glands, and diffuse lymphatic tissue
145
What are characteristics of the submucosa of the nasopharynx?
Loose CT
MALT
146
What are Waldeyer's ring? Where are they located in the nasopharynx?
Ring of lymphoid tissue around the nasopharynx
## Footnote
**Tonsils and adenoids**
147
What are the two major components of the larynx?
**Epiglottis**
**Vestibular folds** (false vocal cords)
**True vocal cords**
148
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
**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
What type of epithelium is contained with the vestibular folds? Lamina propria?
False vocal cords
## Footnote
**Pseudostratified ciliated epithelium**
**Lamina = seromucous glands**
150
What is the general histology of intrapulmonary bronchi?
(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
What type of epithelium is within the true vocal cords of the larynx?
**Stratified squamous epithelium** (resists abrasion)
lack seromucous glands in lamina propria
Remainder of larynx covered w/ pseudostratified ciliated epithelium
152
What types of cartilage and muscle are within the larynx?
**Elastic and Hyaline cartilage**
**Skeletal muscle**
153
What 2 locations in the larynx contain stratified squamous epithelium?
**Lingual surface of the epiglottis**
**True vocal cords**
The rest contain pseudostratified ciliated columnar
154
What are the 3 components of the trachea?
**Mucosa**
**Submucosa**
**Adventitia**
155
What are the characteristics of the mucosa and submucosa of the trachea?
**Mucosa** - respiratory epithelium w/ thick basement membrane
Lamina propria = delicate FECT & lymphatic tissue
**Submucosa -** sero-mucous glands
156
Describe the adventitia of the trachea
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
What are the extrapulmonary components of the lungs?
Left and Right **Primary Bronchi**
From trachea --\> primary bronchi; replacement of hyaline cartilage rings by irregularly shaped cartilaginous plates
158
List the general structure of the lungs from trachea to alveoli
Trachea
Primary Bronchi
Secondary Bronchi/**Segmental**
Tertiary Bronchi
Bronchioles
Terminal Bronchioles
Respiratory Bronchioles
Alveolar Sac
159
Which lung structure begins the intrapulmonary segments?
**Segmental/Secondary Bronchi**
Contain circular rings w/ hyaline cartilage that **transition to irregular plates**
160
What are characteristics of the bronchioles?
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
Where in the lung does gas exchange start at?
Respiratory bronchioles
After the terminating bronchioles
162
What are the characteristics of respiratory bronchioles?
**Low columnar --\> low cuboidal**
Cilia in larger respiratory bronchioles
No goblet cells
Walls contain smooth muscle within FECT
Few alveolar outpocketings
163
Characteristics of Alveolar ducts?
Continuations of respiratory bronchioles
Cone-shaped
**Squamous epithelium**
Wall = smooth muscle w/ FECT
Alveolar sac = several alveoli
164
Define Type I alveolar cells/Type I Pneumocytes
Less numerous than Type II
**Cover largest suface area** (more thinner)
165
Define Type II Alveolar Cells/Pneumocytes
**Produce surfactant**
Cuboidal/rounded
Stem cells for Type I and Type II
166
Define Pores of Kohn
Openings between adjacent alveoli
Allows for alternate pathways for air from one alveoli to the next
167
What are the cell types of the mucosa of the respiratory system?
Ciliated columnar
Nonciliated columnar
Stem Cells
Goblet Cells - mucous secreting; stem cells
Neuroendocrine cells/Small granule cells
168
What are the general characteristics of ciliated/nonciliated columnar cells and stem cells?
**Nonciliated -** contain microvilli, no cilia
**Stem cells -** basal cells of pseudostratified epithelium, self-replace
169
What is the function of neuroendocrine cells of the respiratory system?
**Release catecholamines**
More prevalent in infants; sensory reception(?)
170
What two cells secrete surfactant?
**Clara and Type II Alveolar/Pneumocytes**
171
Characteristics of Type II Alveolar cells
**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
Characteristics of Type I Alveolar/Pneumocytes
Thin cytoplasm
covers 95% of alveolar surface
Basal lamina may be fused with basal lamina of nearby capillaries
173
Define Clara cells, where are they found
**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
What are dust cells and what are their roles?
**Macrophages**; derived from monocytes
Phagocytize pollutants, bacteria, surfactant
175
What relation does dust cells have with congestive heart failure?
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
What are the 3 components of the air-blood respiratory barrier? What is its characteristic?
**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
What is the most important opsonin?
**C3b**
