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Dentistry BDS1 Sem 1 > Tissues of the Body > Flashcards

Tissues of the Body Flashcards

1
Q

What is a tissue?

A

It is a group of cells + intercellular material with a specific organization that work together to carry out one or more functions

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2
Q

What are the primary tissue types?

A
  1. Muscle
  2. Nervous
  3. Epithelium
  4. Connective
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3
Q

What are the morphological characteristics of epithelium?

A

It covers and lines the cavities and form glands

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4
Q

What are the morphological characteristics of the connective tissue?

A

It underlines and supports.

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5
Q

What is the functional property of muscle tissue?

A

It is able to contract and move.

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6
Q

What is the functional property of nervous tissue?

A

It is able to exhibit electrical properties.

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7
Q

What are some of the characteristics of epithelial tissue?

A
  1. It is highly cellular
  2. the layer always has one free surface
  3. Cells attached to the basal lamina
  4. Avascular
  5. Dynamic
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8
Q

What are the two types of epithelium?

A
  1. Surface epithelium

2. Glandular epithelium

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9
Q

What are the two types of glands?

A
  1. Exocrine

2. Endocrine

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10
Q

What are the characteristics of CT?

A
  1. Most abundant
  2. Wide range of cell types
  3. AGS
  4. Highly vascular
  5. CDPST functions
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11
Q

What are the three types of muscle tissue?

A
  1. Skeletal
  2. Cardiac
  3. Smooth
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12
Q

What are the common characteristics of muscle tissue?

A
  1. Elongated muscle fibres
  2. Blood supply housed in connective tissue between fibres
  3. Tissue types separated by a basal lamina
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13
Q

What are the characteristics of nervous tissue?

A
  1. Composed of neurons & neuroglia (helping cells)

2. Monitor & respond to changes both inside & outside the body

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14
Q

What is tissue originates from the ectoderm?

A
  1. Nervous tissue

2. Epithelium

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15
Q

What tissue originates from the mesoderm?

A
  1. Connective tissue
  2. Muscle
  3. Epithelium
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16
Q

What tissue originates from the endoderm?

A
  1. Epithelium
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17
Q

What are two types of membranes?

A
  1. Mucosa

2. Serosa

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18
Q

What junctions are usually present between epithelial cells?

A

Tight junctions

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19
Q

What is basal lamina?

A

It is a layer that lays in between epithelial cells & adjacent CT

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20
Q

What can basal lamina do in terms of the polarity of epithelial cells?

A

Cells need to adapt to the presence of basal lamina, thus basal lamina actually induces polarity

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21
Q

What components make up the basal lamina?

A
  1. Collagen type IV
  2. Laminin
  3. Anchoring fibrils
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22
Q

What is the origin of basal lamina?

A

Collagen and other protein are made by basal surfaces of epithelial cells while reticular lamina and anchoring fibrils are synthesised by CT cells.

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23
Q

What are the components of the basement membrane?

A
  1. Basal lamina

2. Reticular lamina

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24
Q

What are the three major functions of the basement membrane?

A
  1. Filter
  2. Fence
  3. Frame
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25
What is a simple epithelium?
Simple epithelium is an epithelium with only one cell layer
26
What is a stratified epithelium?
Stratified epithelium is an epithelium with more then one cell layer
27
What is a pseudostratified epithelium?
Pseudostratified epithelium is an epithelium that seems to have one layer of cells but actually has more than one.
28
What is the function of simple epithelium?
Facilitates transfer between environments
29
What is the function of stratified epithelium?
Protective barrier function
30
What is epithelium has more than 1 cell type?
It indicates more than one function
31
Which epithelial cells have the largest rate of turnover?
GIT epithelial cells
32
What is metaplasia?
Transformation of one type of epithelium into another. Reversible if the original environment is restored.
33
What is a lumen?
The space above the epithelial cells could be filled with things.
34
What are the three cell surface specializations?
1. Microvilli 2. Cilia 3. Stereocilia
35
What is the core of microvilli?
Actin filaments (microfilaments)
36
What is the main function of microvilli?
Increase surface area of membrane to maximize absorption.
37
What structure makes up cilia?
9+2 microtubular structures
38
What are the three main intercellular junctions in epithelial cells?
1. Tight junctions 2. Gap junctions 3. Desmosomes
39
What is the function of tight junctions?
The main function is to seal intercellular space
40
How do tight junctions occur?
Adjacent cell membrane fuse together
41
What is the structure of tight junctions?
1. Junctional adhesion molecule 2. Occludin 3. Claudin
42
What is the example of the usefulness of tight junctions in the body?
Tight junctions prevent destruction of the gut lining by digestive secretions in the lumen
43
What is the function of desmosomes?
1. Provide strong attachment that holds adjacent cells together
44
What are the functions of gap junctions?
1. Allow for passage of small molecules from adjacent cells | 2. Allows for cell to cell communication
45
What is the composition of gap junction?
Composed of many transmembrane channels called connexons
46
How are junction complexes usually situated?
1. Tight junctions at the top 2. Desmosomes 3. Gap junctions
47
What are hemidesmosomes?
They are basal surface specializations that connect the epithelial cells with basal lamina via fibronectin
48
What is the structure of hemidesmosomes?
1. Keratins attach to intermediate filaments in the cytoplasm 2. Keratin links to transmembrane proteins - integrins 3. Integrins bind extracellular laminin molecules of basal lamina
49
What are the two components of exocrine glands?
1. Secretory units | 2. Ducts
50
What are the two classifications of exocrine glands?
1. Simple | 2. Compound
51
What are simple glands?
They are exocrine glands with a single duct
52
What are compound glands?
They are glands with branched duct system
53
What is a term for the secretory unit of a gland?
Acinus
54
What are the two secretions that exocrine cells produce in the respiratory and digestive systems?
1. Mucous | 2. Serous
55
What are some of the features of serous acini?
1. Secretory granules | 2. High level of acidophilia due to high levels of protein
56
What are some of the features of the mucous acini?
1. Cytoplasm is filled with pale mucous secretory granulse | 2. Well developed Golgi bodies
57
What is the merocrine mode of secretion?
When only secretion is released from cells.
58
What is an apocrine mode of secretion?
When secretion and some cytoplasm is lost
59
What is the holocrine mode of secretion?
When the entire cell becomes secretion
60
What are myoepithelial cells?
They are epithelial cells with muscle-like contractile properties
61
Why is muscle attachments are important for a secretory cell?
Helps with timing of secretion
62
What do mesenchyme cells give rise to?
1. CT cells | 2. Stem blood cells
63
What are the three components of CT?
1. Cells 2. Fibres 3. Amorphous ground substance
64
What types of cells are present in CT?
1. Structural 2. Immature cells 3. Mature cells
65
What are the most common defence cells found in CT?
1. Macrophages 2. Mast cells 3. Plasma cells 4. WBC
66
What is the function of an Amorphous Ground Substance?
It functions as a medium for substance exchange.
67
What are the three main types of fibres present in CT?
1. Collagen 2. Reticular 3. Elastic
68
What is the role of collagen in CT?
Provide strength
69
What is the role of reticular fibres in CT?
Provide net-like framework
70
How can we identify loose CT?
When cells + AGS proportion is higher then fibers
71
How can we identify dense CT?
When cells + AGS proportion is lower than fibres
72
How can we identify dense regular CT?
Fibres will run parallel to each other in dense regular CT.
73
How can we identify dense irregular CT?
Fibres will run in all directions to each other in dense irregular CT.
74
What are some of the functions of dense irregular CT?
1. Connect & bind other tissue types & organs 2. Provide mechanical protection 3. Give support & shape
75
What are some of the functions of dense regular CT?
Transmit force or provide strength in a single direction
76
What are some of the functions of loose CT?
1. Store energy & act as insulation 2. Transport nutrients/waste products between blood & epithelium 3. Protect body from infection
77
What is collagen?
It is a family of proteins
78
What are the stages of collagen-building?
Fibrils to fibres to fibre bundles
79
What collagen composition processes take place in RER?
RER: +Synthesis of procollagen alpha chains with propeptides at each end +Hydroxylation & attachment of sugars to chains +Assembly of chains into triple helix procollagen molecule
80
What collagen composition processes take place in Golgi body?
Golgi: +Packaging of procollagen into secretory veiscles +Exocytosis of procollagen into extracellular space
81
What collagen composition processes take place in Extracellular modification?
Extracellular modification: +Cleavage of terminal propeptides by procollagen peptidases; soluble procollagen becomes insoluble tropocollagen +Tropocollagen molecules aggregate to form collagen fibrils +Fibrils reinforced by covalent cross-links between molecules
82
What is the structure of Type I collagen?
Fibrils, fibres, bundles
83
What is the location of Type I collagen?
Most CT, dermis, tendons, ligaments, bone, dentin
84
What is the function of Type I collagen?
Provides resistance to stress & tension; enables flexibility within tissue.
85
What is the structure of Type II collagen?
Fibrils only
86
What is the location of Type II collagen?
Cartilage
87
What is the function of Type II collagen?
Provides resistance to pressure
88
What is the structure of Type III collagen?
Fibrils & fibers
89
What is the location of Type III collagen?
Reticular fibres, cellular organs
90
What is the function of Type III collagen?
Provides a delicate flexible framework
91
What is the structure of Type IV collagen?
Network sheet
92
What is the location of Type IV collagen?
Basal lamina
93
What is the function of Type IV collagen?
Support of delicate structures, filtration
94
What is the importance of Vitamin C in collagen production?
Vitamin C is used for activation of an enzyme that modifies proline & lysine that is important for the synthesis of collagen
95
What is an important component of elastin?
They are crosslinked
96
What is the composition of AGS?
1. Glycoproteins 2. Proteoglycans 3. Globular protein molecules (binds components together)
97
What is the structure of proteoglycans?
1. Hyaluronic acid core 2. Link protein 3. Protein brunch core 4. GAG of protein brunch core
98
What is a GAG?
It is a chain of disaccharides
99
What is an important part of GAG in term so water?
GAGs have strong negative charges due to sulphate & carboxyl groups. These anions attract water; form a hydrated gel
100
What is the function of Amorphous Ground substance?
1. Contains solvation water 2. Viscosity 3. Megamolecule support 4. Very little free fluid 5. Oedema
101
What is a fibroblast?
It is a younger protein-producing cell, it is active in the production of fibres and AGS
102
What is a fibrocyte?
It is a more mature protein-producing cell that maintenance intercellular components
103
What is the appearance of fibroblasts & fibrocytes on EM?
Long, cytoplasmic processes, features of protein-producing & secreting cell
104
How do fibroblasts/cytes respond to injury?
They release a large amount of collagen
105
What is the appearance of adipocytes in LM?
Huge cell with a thin rim of cytoplasm surrounding a clear lipid droplet
106
What is the function of adipocytes?
Store fat as an energy source
107
What is the origin of a fat cell?
They arise from emsenchymal cells
108
What is the appearance of a microphage in H&E?
Variable; when inactive, only nucleus seen, roundish, often indented.
109
What is the origin of a macrophage?
Monocytes
110
What is the function of the marcophage?
Big eater; uses phagocytoses to engulf different stuff
111
What is the LM appearance of plasma cells?
Ovoid cell, basophilic cytoplasm, nucleus off centre.
112
What is the function of a plasma cell?
Produce antibodies.
113
What is the appearance of mast cells?
Need special dye but is know to reside near capillaries.
114
What is the function of mast cells?
1. Storage of chemical mediators of the inflammatory response 2. Allergy reactions
115
What are the three components of blood?
1. Cells 2. Plasma 3. Cell fragments
116
What is the percentage of plasma compared to other components of blood?
Plasma makes up about 55%, the rest of the material 45%
117
What are the functions of blood?
1. Transportation 2. Protection 3. Regulation 4. Hydraulic functions
118
What are the three common proteins in blood?
1. Albumin 2. Globulins 3. Fibrinogen
119
What are erythrocytes?
They are red blood cells
120
What is a haemoglobin?
It is a protein in erythrocytes that carries about 98.5% of oxygen in blood
121
What are some of the examples of RBC disorders?
1. Low red blood cell count - anaemia | 2. High red blood cell count - polycythaemia
122
What are leucocytes?
White blood cells
123
What are the functions of leucocytes?
1. Fight infection 2. Surveillance for abnormal cells 3. Role in allergic responses
124
What are the 5 types of leucocytes?
1. Granulocytes 2. Agranulocytes 3. Eosinophils 4. Monocytes 5. Basophils
125
What are neutrophils?
They are the most common WBC with multi-lobed nucleus
126
What are eosinophils?
They are a WBC with a bi-lobed nucleus
127
What are basophils?
They are the least common WBC, with a bi-lobed nucleus and they are taking part in the process of anaphylaxis
128
What are lymphocytes?
They are the second-most numerous WBC in blood, single rounded nucleus
129
What are monocytes?
They are macrophage precursors, they have a indented nucleus.
130
What is a normal WBC count?
4-10 billion cells / L of blood
131
What is the name of the condition when the WBC count is low?
Neutropenia
132
What is the name of the condition when the WBC count is high?
Leukocytosis
133
What gives rise to platelets?
A cell that is called a megakaryocyte
134
What are platelets?
They are small cell fragments, anuclear which contain organelles and enzyme
135
What is the main function of platelets?
Form platelet plugs
136
What is cartilage?
It is a specialised CT that provides firm, rigid support
137
What are the two components of cartilage?
1. Cells (chondrocytes) | 2. Matrix
138
What are some of the functions of cartilage?
1. Create a smooth surface, resilient, shock-absorbing | 2. It can be used for the growth of long bones
139
What are the precursors of Chondrocytes?
Mesenchymal stem cells
140
What is the function of Chondrocytes?
Synthesise and secrete matrix
141
What is a lacune?
It is a small hollow space where a chondrocyte sit
142
What is a perichonrdium?
It is a sheath of dense CT that surrounds the cartilage
143
Where is the perichondrium absent?
It is absent in articular cartilage of joints and fibrocartilage.
144
What are the function of the perichondrium?
1. Growth of cartilage 2. Vascular supply 3. Nerves
145
What are the layers of perichondrium?
1st: top layer; Fibrous layer - used for protection 2nd: the layer below the top layer; Chronogenic layer- Inner cellular layer with chondrogenic cells
146
What are the components of the cartilage matrix?
1. Type II collagen 2. Proteoglycans 3. Glycoproteins 4. Water
147
What are the functional significances of cartilage matrix?
1. It is strong 2. avascular 3. Acts as medium of diffusion
148
What are the 3 types of cartilage?
1. Hyaline 2. Elastic 3. Fibrocartilage
149
Where can hyaline cartilage be found?
End of long bones, growth of bones, ribs, nose, larynx, trachea
150
Where can we find elastic cartilage?
The external ear, epiglottis, and larynx
151
Where can we find fibrocartilage?
Intervertebral discs, joint capsules, ligament.
152
What is the concept of endochondral ossification?
Essentially most bones first appears in the fetus as hyaline cartilage that grows and is then systematically replaced by bony tissue.
153
What is an epiphyseal plate?
It is a plate of hyaline cartilage at either end of the bone
154
What is the significance of the epiphyseal plate?
Essentially on either side of epiphyseal plate cartilage grows, this cartilage can then be calcified to create bone
155
What are the zones of the epiphyseal plate?
Starting at the ossification centers: 1. Zone of resorption 2. Zone of calcified cartilage 3. Zone of hypertrophy 4. Zone of proliferation 5. Zone of reserve cartilage
156
What is articular cartilage?
1. It is a cartilage that is situated on the ends of long bones 2. Has no perichondrium 3. Provides a smooth slippery surface
157
What are the two ways cartilage can grow?
1. Interstitial growth | 2. Appositional growth
158
What is interstitial growth?
It is the growth of cartilage from within. Chondrocytes deep in ECM divide and create extra cartilage around
159
What is appositional growth?
It is growth of cartilage through adding extra cartilage at the surface.
160
Why does hyaline cartilage have a limited ability to repair?
Due to avscularity
161
What is the structure of elastic cartilage?
Hyaline cartilage with elastic fibres
162
What is the function of elastic cartilage?
Flexible support
163
What collagen types are present in fibrocartilage?
Type I and Type II
164
What are the three functional classifications of joints?
1. Diarthrosis 2. Amphiarthrosis 3. Synarthrosis
165
What are the three structural classifications of joints?
1. Fibrous 2. Cartilaginous 3. Synovial joints
166
What are the fibrous joints?
Fibrous joints are strong and high in collagen. They provide no movement.
167
What is an example of fibrous joints?
Synarthrodial joint in the skull
168
What are cartilaginous joints?
They are joint with low movement.
169
What is an example of a cartilaginous joint?
Intervertebral discs
170
What is a synovial joint?
It is a freely movable joint
171
What is an example of a synovial joiny?
TMJ
172
What is the composition of bone?
60% mineral, 30% organic, 10% water + cells
173
What are the three main bone cells?
1. Osteoblasts 2. Osteaoclasts 3. Osteocytes
174
What is periosteum?
It is a CT that covers the outside surfaces of bones
175
What is an endosteum?
It is a CT that lines the inner surface of the bone
176
What are the two types of bone marrow?
1. Red bone marrow | 2. Yellow bone marrow
177
What is compact bone?
You can think about the compact bone as the main body of the bone
178
What is spongy bone?
It is a matrix-like end of bones
179
What are the two types of bone?
1. Cortical bone | 2. Trabecular bone
180
What is the make up of compact bone?
1. Haversian systems which have a haversian canal which supplies blood and nerves to the bone
181
What connects the harversian systems?
Volksman cannals
182
What else is present in diagrams of haversian canals?
Osteocytes
183
How is spongy bone organized?
It is basically a sandwich where the compact bone is the bread and spongy bone is the inner part
184
What are osteoblasts?
Bone forming cells
185
What are osteocytes?
Bone remodeling cells
186
What are osteoclasts?
Bone resorbing cells
187
What is the rate of bone turnover in the mandible?
1. Spongy bone every 3 to 4 years | 2. Compact bone every 10 years
188
What are the three types of muscle tissue?
1. Skeletal muscle 2. Cardiac muscle 3. Smooth muscle
189
What are the voluntary muscles of the body?
Skeletal
190
What are the involuntary muscles in the body
Smooth and cardiac
191
What are the myocytes?
Muscle fibers
192
What are sarcolemma?
They are the muscle cell membrane
193
What are sarcoplasm?
They are muscle cell cytoplasm
194
What are myofibrils?
Long structure in the sarcoplasm
195
What are the characteristics of skeletal muscle?
1. They are actually one cell 2. They are multi-nucleated 3. Sarcoplasma contain mitochondria to provide energy for contraction
196
Show the structure of muscle starting from muscle and going down to filaments.
Muscle - fascicles - muscle fibers - myofibrils - thick and thin filaments
197
What is the role of the sarcoplasmic reticulum?
It has a major role in muscle contraction
198
What are T tubules?
They are extensions of the muscle cell membrane that has ions channels that aid in the creation of action potentials
199
What is epimysium?
It is a material that covers the whole skeletal muscle
200
What is fascia?
It is material on the outside of epimysium
201
What is perimysium?
It is a material that divides muscle into sections calld fascicles
202
What is endomysium?
It is a material that surround and individual muscle celll
203
What are muscle fibres made out of?
Myofibrils
204
What is the I band of myofibrils?
It is a light band
205
What is the A band of myofibrils?
It is a dark band on myofibrils
206
What are the characteristics of cardiac muscle?
1. Tey are found only in the heart 2. They have striations 3. They have 1 or 2 nuclei
207
What is the significance of intercalated disks?
They connect cardiac muscle together
208
So how do skeletal muscle contract? In 8 steps
1. Terminal button triggers action potential 2. Action potential moves across surface membrane and through T tubules. This triggers the realease of Ca2+ 3. Ca2+ binds to troponin on thin filaments 4. Ca2+ binding cause tropo-myosin to change shape 5. This triggers myosin cross bridges to attach to actin 6. The binding triggers the bending of myosin corss bridges moving the actin back 7. After the stroke, myosin cross bridges detach 8. Calcium can return back to its storage to be used again
209
What are 4 components of the nervous system?
1. Brain 2. Spinal cord 3. Nerves 4. Ganglia
210
What are the two divisions of the nervous system?
1. Central Nervous System | 2. Peripheral Nervous System
211
What are the three functional divisions of the nervous system?
1. Sensory 2. Motor 3. Integrated
212
What are the two types of control?
1. Voluntary | 2. Involuntary
213
What type of movement are the motor neurons?
Efferent, CNS to PNS
214
What type of movement are the sensory neurons?
Afferent, PNS to CNS
215
What is the composition of nervous tissue?
10% neurons, 90% glial cells
216
In which direction does the signal traveling along the neuron?
From dendrites to axon terminals.
217
What is myelin sheath?
They are structures that insulate the axons
218
What are the nodes of Ranvier?
The uninsulated parts of the axon where impulses jump from one to one.
219
What is the function of the unipolar neurons?
They are sensory neurons.
220
Where are the bipolar neurons found?
1. Eye retina 2. Inner ear 3. Olfactory epithelium
221
What are the two types of multipolar neruons?
1. Motor neurons | 2. Interneurons
222
What type of glia are present in the CNS?
1. Ependymal cells 2. Microglia 3. Oligodendrocytes 4. Astrocytes
223
What are ependymal cells?
They are cells that form ependyma, thin epithelial lining of the CNS cavities called ventricles.
224
What type of epithelium is the ependyma?
Simple columnar epithelium with cilia
225
What are microglia?
They are derivatives of monocytes that act as phagocytic cells.
226
What are oligodendrocytes?
They are cells that provide myelin to the CNS that improves conductivity.
227
What are astrocytes?
They are star shaped cells that provide structural support.
228
What is the significance of astrocytes?
They maintain the blood-brain barrier.
229
What are the two types of matter in the brain?
1. Gray matter | 2. White matter
230
What is the function of gray matter?
The grey matter throughout the central nervous system allows enables individuals to control movement, memory, and emotions.
231
What is the function of white matter?
White matter affects learning and brain functions, modulating the distribution of action potentials, acting as a relay and coordinating communication between different brain regions.
232
A peripheral nerve would contain what type of fibres?
Both motor and sensory
233
Motor information leaves via which horn of the spinal cord?
Ventral horn
234
What are the two types of nerves?
Spinal and Cranial
235
How many pairs of spinal nerves are there?
31
236
How many pairs of cranial nerves are there?
12
237
What is the function of sensory neurons?
1. they are activated by sensory information from the environment 2. They send information to the spinal cord and brain (afferent)
238
What is the function of motor neurons?
1. They send axons to muscles/glands | 2. Efferent pathway
239
What CT surrounds the nerve?
Epinerium
240
What CT surrounds the nerve bundle?
Perineurium
241
What CT surrounds each axon?
Endoneurium
242
What makes up a nerve fibre?
Axon + special covering
243
What is the make up of the CNS nerve fibre?
Axon +/- Oligodendrocyte
244
What is the make up of PNS nerve fibre?
Axon + Schwan cell covering + Endoneurium
245
Why are myelinated fibres conduct nerve impulses faster than unmyelinated fibres?
Due to less space to trave due to nodes of ranvier
246
What is an action potential?
Action potential - is a rapid change of the membrane potential inside the cell from negative to positive and back
247
How can we inactivate a voltage-gated ion channel?
Using a ball and chain theory
248
What is the action of the sodium voltage gated channel.
1. At rest - sodium channels are closed 2. membrane depolarisation - leads to the opening of the channel (activation) 3. Then recovery - ball and chain theory
249
What is the effect of the local anaesthetic on the voltage gatted sodium channel?
Local anaesthetic stabilise the ainactive state of the Nav channel creating üse-dependent" block
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What are the two motes of signalling that are used in synaptic transmission?
1. Electrical signalling through action potentials | 2. Chemical signalling through neurotransmitters
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What is the difference between the excitatory and inhibitory postsynaptic potentials?
Excitatory potentials are able to bring the neuron's potential closer to the firing threshold while inhibitory the opposite.
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What does it mean when we say it is a "presynaptic"?
It means that the force is transmitted from electrical to chemical
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What does it mean when we say "postsynaptic"?
It means that the force is transmitted from chemical to electrical
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What is the presynaptic sequences of events?
1. Presynaptic depolarisation 2. Activation of voltage-gated Ca2+ channels 3. Ca2+ entry, and increased intracellular Ca2+ concentration 4. Ca2+ triggers vesicle fusion and transmitter release
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What is the postsynaptic sequence of events?
1. Transmitter binds at postsynaptic receptors 2. Bound receptors regulate ion conductances 3. Transmitter is cleared by diffusion, enzymatic breakdown or transport

Dentistry BDS1 Sem 1 (15 decks)

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