Histology Quiz #1 Flashcards

1
Q

Simple Epithelium Vs. Stratified epithelium

A

Simple = one layer of cells

Stratified = Multiple Layers of cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Where is Simple epithelium found

A
  1. Lung Alveoli
  2. Gland and duct lining
  3. Germal Epithelium in male and female reproductive organs
  4. Epidermis of skin
  5. Taste buds
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Function of Simple epithelium

A
  1. Passive Diffusion
  2. Secretion + Absorbption
  3. Provide protection on sin
  4. Sensory reception
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Simple squamous epithelium

A

Single layer of thin and flattened cells
- Cells = wide and large irregular shape

Found - heart + blood vessles + Lympatic vessles + Serious memebranes + Air sacs + Bowman’s capsule (Kidney) + Tympanic emebranes

Thin = can allow transfer of material across surface = Function - Diffusion + Filtration + Secretion (Exchange gasses + Nutrients)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Structures in Simple Epethlim

A

Have specialized structures:
1. Microvilia
2. Cilia
3. Sterocillia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Characteristics of Simple epethlium

A
  1. No blood supply (A-vasuclar)
  2. Attaches to basment membrane
  3. Have latteral attatchments (Sides of cels are attached)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Apical vs. basal side of Epithelial cells

A

Apical = Side going towrads the lumen
- Side used for function

Basal = Bottom of cell attached to basement memebrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Simple Squamous epithelium histology

A

Things to look for:
1. Nuceo are taller than cell (Becuase cell is thin)

Image -
Left - Endothelium(Simple squamous epithlimum lining Blood vessles, lymphatic vessles, and heart)

Right - Mesothelium (Simple squamous epithelium lining body cavities - secretes lubricating substances)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Simple cuboidal epithelium

A

Single layer of cube-like cells
- Nucleus = in center
Location - Tubules of kindey + overy + thyroid pancerus + repstory tracts
- Are as tall as they are wide

Function - Protection + absorption + Secretion + Excrete waste

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Histology of SImple cuboidal epithelium

A

Things to notice: Uniform shape + karge spherical nucleus in the center

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Simple columnar epithelium

A

Single layer of tall rectagular epithelial cells (taller than they are wide)

Function - barrier + absorbption + Secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Specilization of Simiple columnar epithelium

A

Specilize in secretion (in reproductive and digestive tracts)

Reproductives - secreted growth hormones and cytokines

Digetsive - Keep out pathogens + facilitate absoption of nutrients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Histology of simple columnar

A

Things to notice - oval shape nucleus closer to the bottom

ALSO see goblet cells (secrete mucus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Psudeofied epithelium

A

Appears to be arranged in layers because nuclei appear at different heights BUT it is only one layer of cells
- IS simple because all cells are attached to the basment memebrane

Location - Respitory tract _ fallopian Tubes

Function - Abroptions or secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Psudeofied epithelium histology

A

Things to look for - Pusdofied epithelial cells = associated with goblet cells

Trachea image = can see the cells are ciliated + have thick basment membrane + near goblet cells

Image 2 - salivary gland

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Apical surface of epithlium

A

Faces environments (face lumen or body cavity)
- Free end of the epithelium

Has 3 specialized sturctures:
1. Microvillia
2. Sterocilli
3. Cilia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Microvilia

A

Finger-like protrusions supported by actin cytoskelaton
- Found on simple cuboidal + columnar epithelium (because function in nutrient uptake)

Location - small intestoine + Proximal tube in kidney

Function - Increases the surface area of the cell to maximize absorption + secretion + reabsorption
- maximizes function of cell surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Histology of microvillai

A

Things to look for: Smaller and narrower than cilia (light pink brush boarder on lumen side)

Small intestine - forms a brush borader

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Cilia

A

Finger-like protrusions that beat in coordinated metachronal waves
- Membrane bound organelle

Location - line respitory tract and follopian tubes

Function -
Trachea = movment of Mucus
Fallopian tubes = movment of ovum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Histology of Trachea

A

See finger projections lining epithelum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Histology of Steroecillia

A

Things to look for - can see projections facing into the lumen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Stereocillium

A

Hairlike protrusion on the surface of sensory cells
- Longer than mcrovilla but similar composition
- Not motile = diffreent from cillia

Location - inner ear + epidermis + vas deferens in male reproductive

Function - Mechanosensors aiding in hearing and balance + increase Surface area to faclitate absprotion in male reproductive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Stratified epithelium

A

Epithlium with multiple layers (only the bottom is in contact with the basement memebrane)

Function - Extrection + secretion + Absorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Stratified Squamous epitheliam

A

2+ layers of flat sheet-like epithliaum
- Has flat nucelus

Function - Protection + prevent wtaer loss + stop pathogen invasion (uses tight junctions)

Non-keratinized and kertinized subtypes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How do you define the shape of stratified epithelium

A

Defined by the shape of cells on teh apical surfce (NOT close to the basal layer)
- basal layer of squamous could be coiboidal or columnar BUT i is still classified as squamous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Non-keratinized statified squamous

A

Wet and permeable

Secretions prevent drying out

Mucous + tears

Location - Esophogus + tongue + pharnyx + vagina + Cornea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Keratinized

A

Cells are filled with keratin and dead - has a lyer of dead cells full of keratin = proetcts against abration on the skin

Dry and impermeable

Protects skin from abrasions

Location - Epidermis + parts of mouth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Histology of Startified squamous

A

Espophogues (non-keratinized) - cels near the lumen are flat and sheet like BUT in multiple layers

Epidermis (keratiziized) - Thicker layer on top = dead cells filled with keratin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Stratified cuboidal

A

2 or ore layers of cube like epithelia + has a round nucelus in the middle

Function - Protects and strength walls of glands and ducts (fond in salivary glands and sweat glands)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Histology of stratifed cuboidal

A

Things to look for - see multiple layers of cube cells with round purple nucelus

Esaphagas - have 2 layers of cube cells with round nuceli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Stratified columnar

A

Layers of stacked epiltheial cells that appear like columns
- More rare form of stratified epithelial

Function - protective + mucus secretion (Ex. lubricate eye)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Histology of Stratified columnar

A

Salivary gland - in top area = statified columnar
- At the bottom see psuedostartified columnar at the bottom (less compact)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Transitional Epithelial Cells

A

Cells that change shape and become flattened when stretched
- Changes shape based on expanding and contracting

Top most cells = umbrella cells (covers the layers of cell beneath them)

Location - Bladder

Function - Allows organs to expad and contract by changing shape

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Histology of Transitional Epithelial Cells

A

Relaxed cells = more circular

Contracted = cells are more elongated (lose distict shape)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Types of Junctions

A
  1. Tight junctions
  2. Anchroing Junctions
  3. Gap Junctions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Tight Junctions

A

Joins the plasma membrane of adjacent cells
- Can be selective about what can get through the junction (uses specialized transport proteins to only take what they want

Function - forms a barrier to prevent diffusiion + seals off intracellular space

Proteins at junctions - Claudin and occulin proteins

Location - In tissue where need selective permeability - Between cells in GI + between endothelial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Celiac and IBD

A

Result from tight junctions abnormalitiesn –> because increase permability = things get in

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Tight Junction Histology

A

See web of tight junctions at base see based on microvillia)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Anchoring Junctions

A

Attaches cells to each other and to ECM

Function - resists mechanical stress + prevents cells from pulling apart

Location - In tissues subject to mechanical stress (Ex. Muscle = epidermis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Composition of Anchoring Junctions

A
  1. Intracellular anchor proteins - form plaques inside cell
  2. Transmembrane adhesion proteins - Link anchor proteins adjacent cel

Transmembrane protein links to inracellular anchr proteins and themselves)
- Anchors through IAP

41
Q

Example Anchoring Junction

A
  1. Adherans Junctions – Connects actin filaments between cellls through cadherin proteins
    • Uses Anchor proteins + transmembrane proteins
    • Example - Adhesion belt - helps make nueral tube (GOOD image on slides)

EM image - See brush boarder + see adherans junction forming adhesion belt structure

Function - cell morphology

42
Q

Example 2 Anchoring Junctions

A

Desmosomes - Connects intermediate filaments (Intermediate filaments are made of keratin)
- Located on the basal lateral surfcae of cells
- CReates intercellular network of filaments
- Spane across and hrough the cell
- Connects cells = forms mesh = can cope with mechanical stress

Structure - have cadherins on extraceullar side and Keratin intermediate filaments in intracellular side

Location - High in cells with lots of mechanical stress

Function - provides tensile strength + structure

43
Q

EM of desmosomes

A

See cadherans and see anchor where dense

44
Q

Gap junctions

A

Links cells cytoplasm together by forming small chanels
- Allows diffusion of small molecule ions + second messsengers + metabolites)
- Can be regulated by the envirnment (chanel c an close if one cell is stressed so damage doesn’t spread)
- Formed by hexons (5 connecins make a connexon)

Function - Allows cels to Coordinates + synchronizes activities (Example - heart contractions + metabolic coupling + embryogensis)
- Hepatocypes - sympathen nerves cans send a second messenger to neighboring cell
- Embryonic - estblish cell identity in groups

45
Q

Gap junction Histology

A

Found in plaques = cluster toegther

Image - can see sende patch with black line

46
Q

Adenomas

A

Beginign epithelial tumors

Starts as epithelial cells

Develop in glandular tissue

Usually doesn’t develope into cancer BUT if they do they develop into Carcinoma

Image - can see growth in surface while the other regions are smooth

47
Q

Carcinoma

A

Cancer that forms in epithelial tissue
- More agressive than adenocarcinomas (seen in image)

Subtypes:
1. Adenocarcinoma - In organ or gland
2. Squamas cell carcinoma - orginates in the squamas

Found in many organs (Skin, breasts, kidney etc.)

48
Q

Adenoma vs. Carcinoma

A

Adenocarcinam:
1. Bengign
2. Grows slower + less agressive
3. Localized/non-invasive

Carcinoma:
1. Cancerous
2. More agressive/grows faster
3. Can stay localized or spread

49
Q

Carcinoma Subtypes

A

Types = based on spread

  1. Carcinoma in situ - has not spread
    • Image = see expansion of cells but can stil see cell sturcture s
  2. Invasive carcinoma - invased local tissue
    • Can see cell structure BUT pentrated more tissue
  3. Metastatic Carcinoma - Has spread
50
Q

Transition from Adenoma to Carcinoma

A

Overalll - cells gain ability to proliferate

Have a series of mutogensis - turn on oncogenes and turn off supressive genes
- Have epigenetic regulation
- Tumors ca secrete kemokines and cytokines to agrevate other cell popultions = provides growth factors and pro inflamatory cytokines to promote cancer

51
Q

Point of malignecey in Carcinoma

A

Point where the rumore can destroy the basal lamina and spread out

52
Q

Myopehelial carcinal

A

Have low mutational burden - mostly fusion genes that are tumoregenic
- Have copy number variants

53
Q

Metaplasia

A

A stimuli-induced observable chnage in tissue cause by chnage in differentiation of progenitor cells - Transition from one cell type to another cell type
- reversible tranistion
- Could be early precursor to cancer

Example - columnar cells transtion to squamas cells

Cause = alchol + chronic endometriosis + smoking + helicopter pylori + salt + HPV + injury + Hormones

Purpose = protect body –> if someone goes wrong with ine cell type then another cell comes in to preform functions instead

54
Q

Types of Metaplasia

A
  1. Acinar to ductal - pancreiatic acinar cells differentiate to ductal cells (pyrmidal epithelial cells to columnar epithelial cells)
    • Going from cells that line glands on pancoues toc ells that line duct of pancreus
  2. Intestinal metaplasia - nonkeritinized squamous epithelium –> ninciliates columnar epithelial cells
  3. Squamous metaplasia - non-squmous epithelium to stratified squamous epithelium
55
Q

Example metaplasia

A

Barrets esophagas - nonkeratinzied squamous epithelium truns into nonciliated columnar epithelial cells
- Go from cells in esophogas to cells found in stomach/intestine

Cause - Acid reflux/GERD

Image - see stratified squalmaous cell with cillia going to intestinal columnar instead

56
Q

Example 2 metaplasia

A

Endometrium

Caused by trauma + IUD + chronic endometriosis

Columnar to squamaous cell type
Image - see columnar epithelial to squashed squamous cells

57
Q

Cilia

A

Long and motile

Come from the basal body in cytoplasm

Project into aplical memebrane

Made of microtubulues and dynein

Use ATP to move in wave like fashion

Often found next to goblet cells thatssecrete mucus –> cilia will then move the mucus (see in histology the black arrow points to goblet cells)

58
Q

Cilia in body

A
  1. Cilia = found in trachea + in lungs

Function - direct the movement of mucus across respitory track to clear the respitry tract of microbes/toxins/devris + protect the lungs

  1. FOund in female reproductive tract - direct movement of Oocytes to from overy to uterus
59
Q

Primary ciliary dyskinesis (PCD)

A

Caused by a defect in cilia - clia is the wrong size or shape so they don’t move correectly OR could be missing cilia alltogether

Symptoms:
1. Have chronic respitory tract infections - because mcirobes buildup i lungs
2. Infertility +
3. Abnormal organ placment - because cilia are involoved in movement of organs during development –> means defective cilia means have organs in wrong place (often mirror image of what should be)

Histolgy.- can see cilia is missing/looks torn

60
Q

Epidermis

A

Composed of keratinocyes (eventually become keratin) + melanocytes + Langerhands cells + Merkel cells
- Keratin = important for epithelial lining

Derived from ectoderm

Function - barrrier between the outter envirnment and inner envirnment

61
Q

What is S. corneum composed of?

A

S. corneum - composed of flatted plates (Squames) of flattened cross linked keratin and lipids

62
Q

S. granulosam

A

S. granulosam - has keratohyalin granuals (ketratin precursors)
- Has laminlar grannuales - produve lipids to prevent dehydration because have glyco lipids on cell surface

Composed of diamond shaped cells (Keratohylalin and laminellar granuals)

63
Q

S. spinosum

A

S. spinosum - thickest layer of the epidermis (has cuboidal and slightly lattened keratinocytes connected by desmosomes)

64
Q

S. basael

A

S. basael - near basement membrane
- Basment membrane = ogin of keratinocyte division

Single basal layer of mitotically active cuboidal keratinocyte

Serperated from dermis by basal lamina

65
Q

Dermis

A

Composed of connective tissue

Divided in papilary and reticular dermis
- reticular - bulk region of collegen (supports the epidermis)

Provides support for the nutrients for epidermis

66
Q

Hypodemermis

A

Compossed of fat + hair follciles + sweat glands + sensory receptors

Layer of subcutenous fat + loss connective tissue

Function - attaches skin to underlying tissue + allows skin to move over muscle and tissue

Histology - see wide region = adipose tissue in the hypodemris

67
Q

Thick skin

A

Glabrous

Found on palms + flexor surfaces + soles of feet

400 - 600 um

68
Q

Thin skin

A

Hairy

75-150 um

Lacks stratum lucidum in epidermis + Stratum spinsum, granulosum, and corneum are narrowing

69
Q

Layers in epidermis

A
70
Q

Melanocytes

A

Location - Hair follciles and Stratum basale

Synthesis melanins + deposit it to nearby cells
- Deposit melanin by making melanin granuals

Histology - pale/while stain
- Melanocytes shrink when process tissue = the cells are surounded by white –> white buble shows melanoctyes
- near melanocyte = keratinocytes have brown dots that show melanin

71
Q

Vitalaigo vs. Alopecia

A

Vitligo = patients don’t have melanoctyoes

Albanism = melanocyes are there but can’t produce melanin or can’t deposit it to keratinocytes

72
Q

Langerhans cells

A

Dendritic cells in skin –> idetofy pathogens and microbes –> THEN phagovytose them –> goes the lymphocytes and shows antigens to lymphocytes
- Phagocytosis for immeidate defense and then go to lymph nodes
- Very motile

Two morphologies:
1. Tissue with infection = active = have star shape (engulfing pathogens)
2. No infection = no star shape

Histology = use IHC (hard to see on H/E)

73
Q

Merkel Cells

A

Primarly in Thick skin

connects to keratinocyes by desmosomes

Function - Mechanoreceptors (receive afferents nerve signal)
- Communicates with nerve
- sneses touch + thermal regulation
- Communicates with keratinocytes

74
Q

Desmosomes

A

Function - adhesion of neighboring epithelial cells + create a tight seal to prevent large foreign proteins or cells from pentrating the skin

Intracellular compoent = intermediate filamenst taht act as anchor

Extracellular compeonent = cadherins that lock with the cadherins of neighboring cell

Keratinocytes in epidermis are tightly joined by desmosomes

75
Q

Hemidesmoses

A

Similar to desmosomes BUT link the dermal and epidermal junction
- tether to the basal lamina through hemidesmosomes

Linkes to lower layer of the basment membrane

Work on apical and basal direction

Image - see cells connected to the basement membrane

76
Q

What layers are affected by Pemphigus Vulgaris and Psrisis

A

PV - affects spinosum in epidermis

Sporisis = affects cornuem in epidermis

77
Q

Desmogleins

A

Transmembrane glycoproteins that mediate epidermal cell-cell adhesion molcules in desmosomes
- Essntial for maintaining integrity of skin and mucous
- Part of desmosomes

Function - cell to cell adhesions + Attchment to basament membrane

78
Q

Acanthosis

A

Thickining of epidermis

79
Q

Acantholysis

A

Seperation of epidermal cells (caused by the breakdown of intercellular connections)

80
Q

Pemphigus vulgaris

A

Autoimmune disorder - autoantigens against desmogolins

Loss of intracellular connections –> Causes blitering
- Keratinocyes in the epidermis and mucosous memebranes lose cell-cell adhesion

Two types:
1. Pemphigus Vulgaris - affects Stratum spinosum
2. Pemphigus foliaceus - affecst stratum foliaceus

Causes - geentic + envirnmental + medications

81
Q

Pemphicus vulgaris mechanism

A

B cell deposite Autoantibodies target desomgleinsin stratum spinosum –> leads to lysis of desmosomes = get dissociated of keratnocytes = get gaps –> fluid fills the gaps and get blisters

End - get blisters or erosions on skin and mouth

82
Q

Secondary complication of pemphigus vulgaris

A

Becuase have blisters and erosions = get infection + weight loss (painful to eat) + gingevitus

83
Q

Pemphigus ulgaris histology

A
  1. Intraepidermal Acantholysis (seperate of spinosum and basal layeer)
  2. Intect basal layer – raised pattern (see in image)

3 – Intraepidermal eosinphils

84
Q

Psorisis

A

Chronic inflamatory skin disease

Causes scaly patches on the skin (often scalp, elbows, knees)

Have increased epidermal cell turnover

Have increased epidermal cell turnover - Keratinocytes have rapid growth and proliferation –> leads to aberant mutuartion –> leads to accumulation of incompletley difefrentated keratinocytes in stratum corneum

85
Q

Psorisis causes

A

Overactive immune system (have positive feedback loop of T cells and Keratinocytes causing inflamation)

Genetic

Envirnmental triggers can cause flares

86
Q

Psorisis clincal manifestion

A

Plaque psorisis = scaly red plaques

Guttate Psorisis = many small red spots

Pustular = get small postules (pus-containing blisters)

87
Q

Psorisis Histopathology

A

Common feature
1. Acanthosis (thickend stratum spinosum in epidermis with elonfated rete ridges)

  1. Parakeratosis with nuertophilic collections (Thickend stratum corneum)
  2. Absent or thin granular layer (Hypogranulosis)

Image - see elongated purple ridges (bone shapes) that go down to the dermis + see thicker corneum (thick pink layer)

88
Q

Epidermal appendages

A

Eccrine sweat glands

Apocrine sweat galnds

Sebbacous Glands

Pilosebecous Units

Located in dermis + Hypodermis

89
Q

Eccrine Sweat Glands

A

All over body

Structure - Inner has cuboidal cells; outside has myoepthilial cell later ; ducts open onto skin

Function - Thermoregulation

90
Q

Appocrine Sweat Glands

A

Present on skin with hair

Structure - Inside has cuboidal cells ; outside has myoepotheal cells; larger lumen

Function - Secretes products that contains proteins

90
Q

Sebbecous Glands

A

Found all around body + in places with hair

Sturcture - Simple branch acinar glands ; duct opens to hair follicle

Function - Holocrine secretion of sebum (Lipids)

90
Q

Pilosebecous glands

A

Contains Hair follicle + arrector pilli muscle + Sebeccous gland

90
Q

Meissner’s corpsucles

A

Mechanico receptors cotaining nerve termials
- enclosed by flattened support cells and connective tissue
- Located in dermal papillae (fingertips + palms + soles of feet)

Function - respond to touch and tactile desxrimination

91
Q

Paccinean corpsicles

A

Mechanico receptors
- Consists of unmylinated nerve endings
- Encapsulted by cicular layers of collegen and fibroblasts
- Located in reticular dermis and hypodermis on palms and soles

Function - respond to coarse touch + pressure + vibrartions

92
Q

Cornification

A

Cells undergoing terminal differential and cell death
- Forms the cornified layer (protects skin from envrinemnt)
- Also call Karatinzation

Examples - epidermis and in hair follcies

93
Q

Cornification hair follicle

A
94
Q
A
95
Q
A
96
Q
A