Tissues Flashcards Preview

Human Organs and Tissues > Tissues > Flashcards

Flashcards in Tissues Deck (68):
1

4 main types of tissues
(cells, amount of ECM, main functions)

1. Connective (aggregated polyhedral cells, small, lining surface or body cavities and glandular secretion)
2. Epithelial (several types of fixed and wandering cells, lots, support and protection)
3. Muscle (elongated contractile cells, moderate, movement)
4. Nervous (intertwining elongated processes, none, transmission of nervous impulses)

2

Wandering cells

Can migrate and move towards/away from different signals

3

Epithelial tissue (location, nutrition, 3 major functions)

L: external and internal surfaces of the body, rest on a basement membrane
N: avascular, so dependent on proximity to connective tissue
F: coverings/linings (protection), absorption (in intestines), or secretions (glands). also sensation and contraction

4

Simple squamous epithelium

Consists of a single layer of flattened cells
Found where there is a rapid passage of chemicals
Can perform some simple secretion and some filtering
Ex: endothelium of lymphatic vessels, alveoli, lining of capillaries, some parts of kindey

5

Simple cuboidal epithelium

Single layer of cube shaped cells
Can allow the passage of chemicals (not as well as simple squamous)
Thicker (more protective)
Have more complex cytoplasm, and perform more complex functions in terms of secretion and absorption
Ex: secretory part of most glands, most tubules of kidney

6

Simple columnar epithelium

Single layer of tall cells
Nucleus tends to be elongated and localized near the basement membrane
Thickness contains many organelles and they have enough energy to carry out complex tasks
Very active in absorption and secretion
May have microvilli and/or cilia
Ex: small intestine and bronchioles

7

Pseudostratified columnar epithelium

Cells are tall and thin but vary in height
All touch the basement membrane, but not all make it to the apical surface
Nuclei may be at varying levels
Ex: trachea

8

Stratified squamous cell epithelium

Multilayered
Named based on the type of cell found at the apical surface
Multiple layers provide increased protection and durability

9

Stratified squamous cell epithelium
Keratinized type

Flattened superficial layer loses their nuclei and become filled with keratin
Constitutes the epidermis

10

Stratified squamous cell epithelium
Non-keratinized, mucosal type

Consists of several layers of cells with the most superficial layer composed of flat living cells
Lines the moist body surfaces such as mouth, esophagus, vagina

11

Stratified cuboidal epithelium

Consists of two or more layers of cells with most superficial being cuboidal in shape
Lines the ducts of sweat glands but otherwise uncommon

12

Stratified columnar epithelium

Consists of two or more layers of cells
Most superficial being columnar in shape
Uncommon but occasionally found in large excretory ducts of some glands and in the cavernous urethra

13

Transitional epithelium

Consists of a stratified epithelium which undergoes marked changes in appearance, depending on the degree of stretch
Lines excretory passages in the urinary system

14

5 types of cell junctions

1. Occluding (zonula occludens or tight junctions)
2. Adhering (zonula adherens)
3. Desmosomes (macula adherens)
4. Communicating (gap junctions)
5. Adhering to basal lamina (hemidesmosomes)

15

Tight junctions

Also called zonula occludens
Form a barrier
Restricts the passage of water, electrolytes and other small molecules across the epithelium
Appear as fusions of the cell membranes to one another, but formed by proteins like occulin or claudin
Attached to actin

16

2 proteins in tight junctions involved infusion

Occulin
Claudin

17

Adhering junctions

Adhering
Sticking adjacent cells together
Made of proteins such as cadherin
Attached to actin filaments all around the cell

18

Desmosomes

Also called macula adherens
Adhering
Points of attachment
Cells can have a bit of space between
Spanned by intermediate filaments (cytokeratin)

19

Gap junctions

Communication
Pores formed by arrangement of connexin proteins (6) that permit passage of ions and other molecules

20

Zonula adherens

Below the tight junctions
Holds the epithelial cells together
Transmembrane cadherins on each cell interact with one another to form a link
Actin on the inside of the cell interacts with the junction and forms a "belt" all the way around the inside of the cell

21

Hemidesmosomes

Cell adhesion on the basal surface
Anchors cells to the basal lamina through laminin
Held together by integrins
Anchored to keratin filaments within cells

22

Exocrine gland

Retain a passage and secrete onto the surface of the epithelium
Have ducts
Can secrete mucus, serous, or sebaceous
Ex: salivary

23

Endocrine gland

Lost contact with the epithelium - secrete into vessels
Ex: thyroid
Can act on neighbouring cells (paracrine) or over long distances (neuroendocrine)

24

What is:
1 mucus
2 serous
3 sebaceous
rich in?

1 glycoproteins
2 proteins and watery
3 lipids

25

Brightfield light microscopy

Suitable for observing the natural colours of a specimen or the observation of stained samples
The specimen appears darker on a bright background

26

Phase contrast microscopy

Useful for observing unstained specimens that lack a color
The optics will convert the differences in refractive index of the specimen into brightness differences

27

Differential Interference Contrast microscopy

Another method of deriving contrast in an unstained specimen from differences in index of refraction
Transforms the phase shift of light, induced by the specimen refractive index, into detectable amplitude differences
Utilizes optical path differences within the specimen to generate contrast the 3D appearance may not represent reality

28

Basic (or cationic dyes)

Have positively charged color radicals forming electrostatic linkages with acidic groups, such as phosphate groups in nucleic acids

29

3 Examples of basic dyes

Toluidine blue
Methylene blue
Hematoxylin

30

Acid (or anionic) dyes

Have negatively charged color radicals establishing electrostatic linkages with basic groups such as basic proteins

31

3 Examples of acid dyes

Orange G
Acid fuchsin
Eosin

32

Magnification equation

Image size/actual size

33

Numerical aperture

The ability of the lens to collect the light

34

What cells make collagen?

Fibroblasts

35

What two cell lines do connective tissue come from? And where did these cells originate?

From hemaotpoietic stem cells and undifferentiated mesenchymal cells
These came from the mesoderm of the germ layer of the embryo

36

Fibroblasts

Synthesize collagen, elastin, proteoglycans and glycoproteins
Most common type of cell in connective tissue proper

37

Proteoglycans

Made up of glycosaminoglycans
Very good at absorbing water (90% of the ECM)
ECM is very good at resisting compressive forces because of this
Protein core and an extension of GAG (most GAGs can attach to core proteins

38

Glycosaminoglycans

Linear (no branches) polysaccharides consisting of repeating disulphide units
They are charged and attract water (hydrophilic)
They are inflexible
Resistant to compressive forces

39

Collagen fibers

Wide and wavy in appearance
Stain pink
Most abundant protein of ECM and body
30% of the protein in the body is collagen
Over 25 different types of collagen

40

Elastic fibers

Thing, flexible fibers made from elastin
Stain black
Branched and coiled
May be stretched up to 150% of their resting length
Produced by fibroblasts and smooth muscle cells of arteries

41

Reticular fibers

Thin collagen fibers - mostly type 3 collage
Spider web appearance
Stain black
Produced by reticular cells

42

3 things connective tissue proper is made up of

1. Cells (mostly fibroblasts)
2. A homogenous ground substance or matrix, which may be tissue fluid, an amorphous gel-like material, or solid
3. Extracellular fibers (collagens, reticular and elastic)

43

Loose connective tissue

Contains many cells, a loose arrangement of fibers, and moderately viscous fluid matrix
Many cells, few fibers

44

Areolar connective tissue

A type of loose connective tissue
Slippery and supportive outer coat of organs
Attaches epithelial tissue to other underlying tissue

45

Reticular connective tissue

A type of loose connective tissue
Web like internal skeleton for some organs

46

Dense connective tissue compared to loose

Contains more fibers but less matrix and fewer cells when compared to loose

47

Regular connective tissue

A type of dense CT
Collagen fibers are densely packed and arranged in parallel
Found in ligaments and tendons
Resistant to tension forces in one direction, but allow some stretch
Attenuated fibroblasts found between groups of fibers

48

Irregular connective tissue

A type of dense CT
Contains a dense woven network of collagenous and some elastic fibers in a viscous matrix
Found in joints and forms the dermis of skin
Impact resistant, strength in all directions

49

Pericytes

Contractile cells that wrap around the endothelial cells of capillaries and venules throughout the body

50

White Adipose Cells

Responsible for the synthesis and storage of fat (long-term energy reserves)
Largely made up of TAGs - high in energy
Other less efficient energy source is glycogen (mainly liver, skeletal muscle)
Unilocular

51

Unilocular definition

The cytoplasm and nucleus squeezed to a thin rim around the periphery of the cell (cells do not divide)
Forms adipose tissue when present in large numbers

52

Brown adipose cells

Multilocular
Provide body heat (thermoregulation)

53

Multilocular

These cells contain many small fat droplets, and groups of these cells form brown fat

54

3 types of cartilage

1. Hyaline (most common, found in joints and resp passages, collagen fibers)
2. Fibrocartilage (associated with dense connective tissue and is resilient, in vertebral discs, strongest (most fibers))
3. Elastic (more flexible, in the ear, elastic fibers, most cells)

55

Functions of compact and spongy bone

Compact: strong, so supports the entire body
Spongy: porous nature = greater SA - allows bone marrow to develop in the region

56

Canaliculi

Microscopic canals that radiate out from the lacunae

57

Lamellae

Concentric layers of the osteon

58

Osteoblasts

Synthesize the organic components of the matrix (collagen, proteoglycan, and glycoproteins)
Located at the surface of bone tissue
Differentiate into osteocytes

59

Osteocytes

Derived from osteoblasts
Found in lacunae (cavities) Involved in the maintenance and mineralization of bone

60

Osteoclasts

Multinucleated cells involved in the reabsorption of bone tissue

61

Smooth muscle

Surrounding blood vessels and intenstine
Single central nuclei
Lack striated appearance

62

Skeletal muscle

Movement of skeleton
Long fused cells
Multiple offset nuclei
Striated appearance

63

Cardiac muscle

Contraction of the heart
Branched cells
Single offset/central nuclei
Striated
Has intercalated discs

64

Neuroglia

Or glial cells
Assist the propagation of the nerve impulse and provide nutrients to the neuron

65

Mesothelium

The simple squamous epithelium that covers the body cavities

66

3 parts of connective tissue

Cells
Ground substance
Fibers

67

Stroma

Connective tissue within organs
Forms a structural framework that aids in organ function

68

Some functions of connective tissue

Forming a site for storage of fat (e.g., storage of energy reserves)
Aiding in the defense and protection of the body (e.g., infection)
Reduces friction (e.g., reduction of wear on joints)
Repair after injury (e.g., fibroblast remodeling of damaged tissue).
Bones, cartilage provide structural form while ligaments hold bones together, and tendons attach muscles to bone.
Blood transports gases, nutrients, waste, performs immune functions, wound healing.