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Flashcards in Histology Deck (52):
1

What is pseudostratified columnar epithelia?

Single layer of cells of differing heights

2

What is transitional epithelia?

Where the basal cells are cuboidal or columnar and the apical cells are squamous or dome-like

3

What is mesothelium?

Simple squamous epithelia which lines closed body cavities

4

What are exocrine glands?

Ducted glands which secrete substances onto epithelium

5

What are endocrine glands?

Duct-less glands which secrete substances directly into the blood

6

What is a serosa?

Complex tissue which lines closed body cavities and consists of epithelia and underlying connective tissue

7

How many microns are there in a millimeter?

1,000

8

What are all connective tissue cells derived from?

Mesenchymal cell

9

Name the 5 types of connective tissue

Fibrocollagenous, cartilage, blood, bone, fat (adipose)

10

How is fibrocollagenous tissue classified?

By quantity of collagen fibres, type of collagen fibre, and organisation of collagen fibres

11

Describe loose/areolar fibrocollagenous connective tissue

Relatively little type I collagen (in random directions), some type III collagen, some elastic fibres, has fibroblasts, mast cells, macrophages and some white blood cells

12

Describe dense irregular fibrocollagenous connective tissue

Abundance of collagen type I (in random directions), some elastic fibres, fibroblast is main cell, provides ability to withstand tension in many directions

13

Describe dense regular fibrocollagenous connective tissue

Abundance of collagen type I (in one direction only), few elastic fibres, mainly fibroblasts, found in tendons and most ligaments, withstands great tensile strength if force applied in one direction

14

Describe reticular fibrocollagenous connective tissue

Fine meshwork of collagen type III, loose ground substance, soft internal skeleton formed by fibres (stroma), mainly found in lymphoid organs

15

Describe white adipose connective tissue

Main adult fat store, insulates, shock absorber, made of unilocular adipocytes (lipids fuses into one big droplet)

16

Describe brown adipose connective tissue

Involved in thermoregulation in neonates, multilocular adipocytes, organised into lobules by fibrocollagenous septa

17

Describe the extracellular matrix of cartilage

Sulphated GAGs, rich in proteoglycans and hyaluronic acid and type II colalgen

18

What are the different types of cartilage?

Hyaline, elastic and fibrocartilage

19

Where do chondrocytes lie?

In lacunae (lake)

20

Describe fibrocartilage and where it is found?

Contains both type I (stronger) and type II collagen fibres and is found in IV discs, pubic symphysis, and knee menisci

21

What is the perichondrium?

A specialised layer of condensed, highly vascular fibrocollagenous tissue with chondroblasts embedded (for repair)

22

What are muscle cells derived from?

Mesoderm

23

What is the basement membrane of muscle cells called?

External lamina

24

Why does muscle stain bright pink?

Due to large amounts of myofilament in cytoplasm

25

Describe endomysium

Supporting reticular fibre network which carries capillaries and nerves to the muscle cells (fibres)

26

Describe perimysium

Surrounds muscle fascicles

27

Describe epimysium

Surrounds whole muscle with collagen and elastic fibres embedded, it is continuous with tendons and muscle attachments

28

What are satellite cells?

Stem cells which can add to muscle, and are found beneath the basement membrane

29

What do fibroblasts do in muscle?

Help produce endomysium

30

What is the H-zone?

Just the myosin filament, no overlap with actin

31

What is the I-band?

Just the actin filament

32

What is the A-band?

All of the myosin filament, including overlap with actin

33

What is the M-line?

Thickest portion of the myosin filament

34

What is the Z-line?

Marks end of sarcomere (actin)

35

Describe cardiac muscle cells

Branching, multinucleate cells which meet at intercalated discs

36

Why does a fibrocollagenous scar form in cardiac damage?

Cardiac muscle doesn't have any satellite cells and therefore cannot repair itself and a scar forms instead

37

Describe smooth muscle cells

Spindle-shaped cells with a central nuclei, no striations and that are closely arranged to form sheets

38

What are myoepithelial cells?

Cells which have processes which surround secretory portions of exocrine glands, and contraction allows movement into the duct

39

What are myofibroblasts?

Specialised cell that produces collagen it also have actin and desmin filaments which have a large role in wound healing --> proliferate to produce fibrocollagenous scar --> contraction reduces the size of damaged area in healing process

40

What are pericytes?

Stem cells that are associated with capillaries and venules, and following injury proliferate to form new endothelial cells, fibroblasts or myofibroblasts

41

What does a Nissl stain show?

It stains RNA and DNA

42

What is a nervous system nucleus (or PNS ganglion)?

Collection of neurones with common circuity and function (in grey matter)

43

What is neuropil?

Dense tangle of neuroal axons, dendrites and glial processes and is site of communication between various components

44

What glial cells are present in the central nervous system?

Oligodendrocytes, astrocytes and microglia

45

Describe astrocytes

Highly branched cell that surrounds the surfaces of neurones and blood vessels in the CNS and an important part of the BBB; proliferates at the site of injury to form a 'glial scar'

46

Describe oligodendrocytes

Produce myelin by wrapping membrane around axons (one cell can myelinate many axons)

47

Describe microglia

Specialised macrophages in CNS (smallest cell and hard to see without stain)

48

What glial cells are present in the peripheral nervous system

Schwann cells and satellite cells

49

Describe Schwann cells

Myelinate axons (1 Schwann cell segment per axon)

50

Describe satellite cells

Similar to the astrocytes of the CNS (physical and metabolic support)

51

Define 'motor unit'

Motor neurone and all of the skeletal muscle fibres it contracts

52

What does immunohistochemistry involve?

Using labelled antibodies to detect specific antigens in tissue secretions; primary antibody binds to antigen and then a secondary antibody binds to that antibody with a marker e.g. fluorescence