1
Q
what tissues does oral histology include
A
- the lining of the mouth
- the tissues of the tongue
- the periodontium
- the tooth
- the salivary glands
- also includes the study of the process of facial and tooth development (embryology)
2
Q
the practice of dentistry and dental hygiene is based on knowledge of:
A
- structure
- arrangement
- reactions
of all oral tissues
3
Q
why is it important that we know the basics of how cells are gathered in tissues
A
- to understand how oral tissues react to prevent or produce disease
4
Q
how can we understand diseases caused by oral biofilm
A
- study of tissue structure
- study of tissue reaction
- study of tissue repair (from removal of calculus)
5
Q
what is histology
A
- the science and study of tissues
- from a cellular to tissue level
6
Q
what is a tissue
A
- a group of similar cells surrounded by intercellular (between cells) substance (IS)and tissue fluid
- a group of cells combined in a specialized manner to perform a particular function
7
Q
types of tissues:
- hard
- sturdy/elastic
- delicate
- secretory
- nutritive
A
- hard: bone
- sturdy/elastic: skin
- delicate: lining
- secretory: salivary glands
- nutritive: blood
8
Q
how do we study tissues
A
- microscopically using stains
9
Q
how do we prepare microscopic slides
A
- small piece of tissue removed from body
- fixative placed (preservation) and sent to lab
- specimen dehydrated in alcohol
- placed into melted paraffin wax
- paraffin block thinly sliced with a microtome
- arranged on slides
- wax removed with xylene
- stained
10
Q
components of a tissue
A
- cells
- intercellular substances (IS)
- tissue fluid (interstitial fluid) (IF)
11
Q
structure of cells
A
- rbc: no nucleus
- wbc: one or several nuclei
- muscle cells: contract
- fat: displaced nucleus (pushed against cell walls)
12
Q
what is intercellular substance
A
- in between cells; colourless and transparent
- is a product of cells, holds them together
- provides medium for passing nutrients and removing wastes to and from capillaries
- serves as a physical barrier to prevent the penetration of foreign substances into tissue
- IS occurs in 2 main forms: fibrous; amorphous - shapeless, gel-like known as ground substance (serves as the barrier mentioned above)
- differs in different tissues: bone - mostly IS, little cells; skin - mostly cells, limited IS (dryer)
13
Q
tissue fluid
A
= interstitial fluid
- very similar to blood plasma
- part of blood which can diffuse through walls of capillaries and then drains back into blood through osmosis
- in tissues, nutrients are carried out through capillary walls to surrounding IS and then to the cells; waste products of the cells are returned from IS to the capillaries
- different tissues have different amounts of TF
- blood vs skin
14
Q
4 types of primary tissues
A
- epithelial tissue
- connective tissue
- muscle tissue
- nerve tissue
divided based on shape, type and amount of; cells, intercellular substance, tissue fluid
15
Q
epithelial tissue groups and subgroups
A
surface cells of covering and lining membranes
A - simple: squamous, cuboidal, columnar
B - pseudostratified columnar
C - stratified: squamous, cuboidal, columnar, transitional
16
Q
epithelial tissue
A
- very little or no IS or IF, many cells
- avascular (has no blood supply of its own) -> O2/nutrients obtained by diffusion from highly vascularized underlying CT
17
Q
what is a basement membrane
A
- composed of 2 layers - made up of fibers and ground substance
- basal lamina: secreted by ep. cells and is mostly ground substance
18
Q
what does epithelial tissue give rise to
A
- liver, pancreas as well as salivary glands, thyroid gland and
- enamel organ: produces enamel of developing teeth
19
Q
2 major groups of epithelial tissue
A
- covering and lining epithelium: covers body surfaces, lines body cavities, hollow organs and vessels
- glandular tissue: forms glands
20
Q
what is glandular tissue (2nd type of glands)
A
- specialized epithelial cells secrete substances mucus, hormones
- 2 major types glands: exocrine glands (duct glands, secretions lead to external surfaces of body), endocrine glands (ductless glands, secretions, such as hormones, enter the blood)
21
Q
3rd type of glands
A
exocrine and endocrine glands
- pancreas: endocrine function: secretes insulin and glucagon; exocrine: excretes enzymes to break down proteins
- liver: endocrine function: secretes IGF-1 (has insulin like effects and stimulates growth in the body); exocrine: secretes bile into intestine
- sex glands
22
Q
3 epithelial groups
A
- covering and lining epithelium
- glandular tissue
- mixed endocrine and exocrine
23
Q
connective tissue
A
- fibrous connective tissue
- areolar connective tissue
- adipose (fat) tissue
- hemopoietic (blood) tissue
- cartilage
- bone
- mesenchyme (gives rise to connective tissue)
24
Q
fibrous regular connective tissues
A
- arranged in parallel bundles
25
fibrous irregular connective tissues
- not parallel bundles
26
what is the dermis made up of
- mostly fibres, less rigid than the dense regular
27
what was the fibres of fibrous connective tissues produced by
- cells called fibroblasts: predominant cells in fibrous connective tissue
28
areolar connective tissue
- loose connective tissue
- attaches skin to muscles; organs to body membranes
- subcutaneous layer
- think of when you remove skin from meat and there’s little strings between the skin and the muscle – that’s areolar tissue
29
adipose (fat) tissue
- store fat: displace nucleus and cytoplasm
| - located in soft tissue and yellow bone marrow
30
hemopoietic (hemo=blood; poietic=to make)
- tissues that produce blood cells (rbc and wbc) to remove worn out blood cells from the bloodstream
- occurs as rbm and lymphatic tissue (tonsils, nodes where cells differentiate into wbc)
31
cartilage
- cells are called chondrocytes
- most skeletal fetus first made of cartilage which resorbs as bone tissue - replaces it
- in adults it comprises parts of the nose, trachea, larynx, ear
32
bone
- is mineralized connective tissue
| - cells are called osteocytes
33
mesenchyme
- embryonic or young connective tissue
- undifferentiated cells that will form connective tissue of the body and blood
- tissue that has not been differentiated
34
nerve tissue
- forms nervous system
- nerve cells are called neurons
- highly specialized cell = react to stimuli (excitable) and conduct nerve impulses
35
2 main divisions
- CNS: brain and spinal cord
| - PNS: nerves leaving CNS, nerves associated with other organs
36
muscle tissue
- muscle cells are much longer than wide -> each muscle cell is called a muscle fibre
37
3 divisions of muscle tissue
based on appearance and muscle control
1. non-striated (smooth) involuntary
2. striated voluntary
3. striated involuntary
38
what do the tissues of the oral cavity originate from (basic tissues)
- epithelial tissue: gives rise to mucous membranes and salivary glands
- connective tissue: gives rise to jaw bone, fibres of periodontal ligament
- muscle tissue: give rise to muscles attached to mandible and form tongue
- nervous tissue: give rise to nerves that supply oral cavity
39
what are the tissues of the tooth
- anatomical crown: covered by enamel (epithelial cells)
- anatomical root: covered by cementum (CT cells)
- cervix: neck of the tooth b/w root and crown
- dentin: bulk of tooth in crown and root (CT)
- pulp: in crown and root (CT)
- in crown - pulp chamber
- in root - pulp canals
Histology
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