Tissue Level Of Organization Flashcards
1
Q
What is a tissue?
A
Collections of cells and cell products that perform specific, limited functions.
2
Q
What is histology?
A
Study of tissues
3
Q
What is epithelium tissue?
A
- Covers exposed surfaces
- Lines internal passageways
- Forms glands
4
Q
What is connective tissue?
A
- Supports other tissues
- Fills internal spaces
- No contract with the environment
5
Q
What is muscle tissue?
A
- Specialized for contraction
- Skeletal, cardiac, and smooth muscles
6
Q
What is neural tissue?
A
- Carried electrical signals from one part of the body to another
7
Q
What are the five characteristics of epithelial tissue?
A
- Cellularity (Cell junctions)
- Polarity (Apical and basal surfaces)
- Attachment (Basement membrane)
- Avascularity (No blood vessels)
- Regeneration
8
Q
What are the four functions of epithelial tissue?
A
- Physical protection
- Control permeability
- Sensation (Neuroepithelium)
- Secretions (Glandular epithelium)
9
Q
How do you increase surface area?
A
- Microvilli increase absorption or secretion
- Cilia (ciliated epithelium) move fluids
10
Q
What are the three ways the integrity of epithelial tissues are maintained?
A
- Intercellular connections
- Attachment to basement membrane
- Maintain and repair
11
Q
How does intercellular connections work?
A
- Bonds between adjacent cells
- Support and communication
- Includes:
- Tight junctions
- Gap junctions
- Desmosomes:
- Belt
- Button (spot)
12
Q
What is the basement membrane (basal lamina)?
A
- It has two layers:
- Lamina lucida- Thin layer
- Produced by epithelium
- Lamina densa - Thick fibers
- Produced by connective tissue
- Attachment of epithelial cells to basal lamina:
- Hemidesmosomes
13
Q
How are epithelial cells maintained and repaired?
A
They are replaced by division of germinative (stem) cells near the basal lamina.
14
Q
What are the two classes of epithelial tissues?
A
- Epithelia: (AKA surface epithelium)
- Layers of cells covering external or lining internal surfaces. - Glands:
- Structures that produce secretions
15
Q
What are the two classes of surface epithelium?
A
- Cell shape
- Squamous epithelia: flat shaped
- Cuboidal epithelia: square shaped
- Columnar epithelia: tall shaped - Layers
- Simple epithelium: single layer of cells
- Stratified epithelium: several layers of cells
16
Q
What are the two types of squamous epithelium?
A
- Simple squamous epithelium
- Most delicate epithelium: diffusion and absorption
- Mesothelium- endothelium- lung alveoli - Stratified squamous epithelium
- Toughest type of epithelium: physical protection
- Skin- lining of mouth, esophagus, rectum, vagina…
17
Q
What are the three types of cuboidal epithelium?
A
- Simple cuboidal epithelium
- Absorption and secretion
- Renal tubules- thyroid gland - Stratified cuboidal epithelium
- Protection, absorption, and secretion
- Sweat and mammary gland ducts - Transitional epithelium
- Stretch and recoil
- Urinary bladder- uterus
18
Q
What are the three types of columnar epithelium?
A
- Simple columnar epithelium
- Absorption and secretion
- Stomach- intestine- uterine tubes - Stratified columnar epithelium
- Protection
- Salivary gland ducts - Pseudostratified columnar epithelium
- Protection, secretion, and cilia movement
- Trachea- bronchi
19
Q
What are the two types of glandular epithelium?
A
- Endocrine glands
- No ducts (ductless glands)
- Release hormones into interstitial fluid —> blood
- e.g thyroid gland- adrenal gland… - Exocrine glands
- Have ducts
- Produce secretions —> ducts —> epithelial surfaces
- e.g sweat glands
- Modes of secretion
20
Q
What are the modes secretion? (Crine)
A
Modes of secretion:
- Merocrine secretion
- Released by vesicles (exocytosis)
- e.g sweat glands- salivary glands
- Apocrine secretion
- Released by shedding cytoplasm
- e.g mammary gland
- Holocrine secretion
- Released by cells bursting
- Gland cells are replaced by stem cells
- e.g sebaceous gland
21
Q
What are the three types of exocrine glands?
A
Serous glands:
watery secretions
e.g., parotid salivary gland
Mucous glands:
secrete mucins
e.g., sublingual salivary gland
Mixed exocrine glands:
both serous and mucous
e.g., submandibular salivary gland
22
Q
What is the structure of exocrine glands?
A
Unicellular
Multicellular
23
Q
What is the unicellular exocrine gland?
A
Goblet cells:
the only unicellular exocrine gland
scattered among epithelia:
e.g., in intestinal lining
secrete mucin
24
Q
What are multicellular exocrine glands?
A
Structure of the duct:
simple (undivided)
compound (divided)
Shape of secretory portion:
tubular (tube shaped)
alveolar/acinar (blind pocket/chamber)
tubuloalveolar/tubuloacinar
Relationship between ducts and glands:
branched (several secretory areas sharing 1 duct)
25
What is an example of a coiled tubular gland?
Merocrine sweat glands
26
What is an example of simple branched alveolar glands?
Sebaceous (oil) glands
27
What is an example of a compound tubular?
Testes (somniferous tubules)
28
What is an example of compound alveolar (acinar)?
Mammary glands
29
What is an example of compound tubuloalveolar?
Salivary glands
Pancreas
30
What are the four functions of connective tissues?
1. Connect epithelium to the rest of the body
2. Provide structure
3. Store energy
4. Transport materials
31
What are the components (2) of connective tissues?
Specialized cells
Extracellular matrix (most of the tissue volume:
(Fibres and ground substance)
- solid: protein fibers
- fluid: ground substance
32
What are the three classifications of connective tissues?
Connective tissue proper:
connect and protect (fat & tendons)
Fluid connective tissues:
transport (blood & lymph)
Supportive connective tissues:
structural strength (cartilage & bone)
33
What is in the connective tissue proper's matrix?
Fibers and ground stubstance
34
What are the permanent residents in connective tissue proper?
1. Fibroblasts (most abundant most important)
2. Adipocytes
3. Mesnchymal cells
4. Melanocytes
35
What are the migratory substances in connective tissue proper?
1. Lymphocytes
2. Macrophages
3. Microphages
4. Mast cells
36
What are fibroblasts? (Proper CT)
Most abundant cell type.
Found in all connective tissue proper.
Secrets proteins (tubers) and hyaluronan (cellular cement).
(permanent residents)
37
What are adipocytes? (Proper CT)
Fat cells.
Each cell stores a single, large fat droplet.
Like normal cells, but have a large fat drop that fish away the nucleus.
(permanent residents)
38
What are mesenchymal cells? (Proper CT)
Stem cells (mother cells).
Divide to compensate for injury, they then differentiate into fibroblasts, macrophages, ect...
(permanent residents)
39
What is melanocytes? (Proper CT)
Synthesize and store the brown pigment.
Makes skin, hair, eye, and nipple colours.
(permanent residents)
40
What is lymphocytes? (Proper CT)
Specialized immune cells in blood and lymphatic system.
2 main types T & B lymphocytes.
B lymphocytes may develop into plasma cells which antibodies.
(migratory)
41
What are macrophages? (Proper CT)
Large, amoeba-like cells.
Part of immune system; engulf pathogens and damage cells.
2 conditions: free macrophages migrate (monocytes in blood) and fixed macrophages stay in tissue (kupffer cells in the liver).
Basically eats things not required by the cell.
(migratory)
42
What are microphages? (Proper CT)
Small, phagocytic blood cells.
Respond to signals from macrophages and mast cells.
e.g, neutrophils and eosinophils, more acidic.
(migratory)
43
What are mast cells? (Proper CT)
Stimulate inflammation after injury or infection.
Granules release histamine and heparin.
Basophils are mast cells carried blood, not tissue.
(migratory)
44
What are the types of fibers of connective tissue proper?
Collagen fibers.
Reticular fibers.
Elastic fibers.
These are all formed by fibroblasts.
45
What are collagen fibers? (Proper CT)
Most common fibres in CTP.
Long, straight, and unbranched.
Strong and flexible.
Bundle of fibbers protein strands.
Resist force in one direction along the longitudinal axis.
Tendons and ligaments.
46
What are reticular fibers? (Proper CT)
Network of interwoven fibers (stroma).
Strong and flexible.
Resist force in many directions.
Stabilize functional cells (parenchyma) and structures).
Sheaths around organs.
47
What are elastic fibers? (Proper CT)
Contain elastin protein.
Branched and wavy, not as intense as reticular fibers.
Flexible; return to original length after stretching.
Elastic ligaments of vertebrae and ear lobe.
48
What is the ground substance? (Proper CT)
Fills spaces between cells.
Clear and colourless.
Viscous and dense as it slows down pathogens.
49
What are the two categories of connective tissue proper?
Loose connective tissue: more ground substance, less fibers such as fat.
Dense connective tissue: more fibers, less ground substance such as tendons.
50
What are the three types of loose connective tissues?
These are the packing materials of the body.
Areolar.
Adipose.
Reticular.
51
What is areolar tissue? (Lose Proper CT)
Least specialized
Open framework
Viscous ground substance
Elastic - retains shape after stretch
Absorbs shocks
Holds blood vessels and capillary beds
e.g., subcutaneous tissue (under skin)
52
What is adipose tissues? (Lose Proper CT)
The main cell is adipocytes.
There are two main kinds.
White fat:
Most common
Stores lipids
Absorbs shocks
Insulator
Brown fat:
Only in infants and young children
More vascularized
Adipocytes have many mitochondria
Breaks down fat
Produces heat
53
What is liposuction?
Surgical removal of unwanted adipose tissue
Treatment of obesity & lipodystrophy
Problem may recur as tissue regenerates
54
What is reticular tissue? (Loose Proper CT)
Complex and 3D network.
Reticular fibers (stroma): support functional cells (parenchyma).
Reticular organs: spleen, liver, lymph nodes, bone marrow, and kidneys.
55
What is dense connective tissue?
Tightly packed with high numbers of collagen or elastic fibers(collagenous tissues)
Types:
regular connective tissue
irregular connective tissue
56
What is dense regular connective tissues?
Attachment and stabilization
Tightly packed, parallel collagen fibers:
tendons: attach muscles to bones
ligaments: connect bone to bone and stabilize organs e.g., liver
aponeuroses: CT sheets attached to flat muscles
Subtype:
elastic tissue …
57
What is elastic tissue? (Dense Proper CT)
Subtype of dense regular CT
Made mainly of elastic fibers
e.g., elastic ligaments of spinal vertebrae
58
What is irregular connective tissue? (Dense Proper CT)
Strength in many directions
Interwoven networks of collagen fibers
Locations:
dermis, perichondrium, periosteum, organ capsules, …
59
What is fluid connective tissues? (Dense Proper CT)
Include:
blood
lymph
Components:
watery matrix of dissolved proteins
specific cell types (formed elements)
60
What is blood? (Dense Proper CT)
Fluid content (plasma)
Formed elements:
red blood corpuscles (RBCs) (erythrocytes)
white blood cells (WBCs) (leukocytes)
platelets (thrombocytes)
61
What is lymph? (Dense Proper CT)
Collected from interstitial space
Monitored by immune system
Transported by lymphatic vessels
Returned to venous system
62
What are the two supportive connective tissue?
Support soft tissues and body weight:
cartilage:
gel-type ground substance
for shock absorption and protection
bone (osseous tissue):
calcified (rigid by calcium salts, minerals)
for weight support
63
What is cartilage?
Structure:
cells: chondrocytes located within lacunae (chambers)
matrix: firm gel
No blood vessels
Perichondrium: dense irregular CT
covers cartilage surfaces
has 2 layers:
outer, fibrous layer (for strength)
inner, cellular layer (for growth and maintenance)
64
What are the three types of cartilage?
Hyaline
Elastic
Fibrocartilage
65
What is hyaline cartilage?
Tough, flexible support.
Reduces friction in joints.
Translucent matrix.
No predominate fibers.
Synovial joints, rib tips, sternum, and trachea.
(Most abudnet)
66
What is elastic cartilage?
Flexible support.
Tightly packed elastic fibre.
Found in the external ear and epiglottis.
67
What is fibrocartilage?
Resits compression.
Prevents bone-to-bone contact.
Limits movement.
Very dense collagen fibers.
Found in weight baring areas such as knee pads, symphysis pubis, and intervertebral discs.
68
What is bone (osseous tissues)?
Strong: calcium salt deposits.
Resists shattering: flexible collagen.
Faster to heal, and very vascular.
Calcium makes bones strong.
Structure:
bone cells (osteocytes):
located within lacunae
arranged around central canals within matrix
canaliculi: small channels through matrix – access blood supply
Rich blood supply
Periosteum: dense irregular CT
covers bone surfaces
2 layers:
outer fibrous layer
inner cellular layer
69
What fascia?
Body’s connective tissue framework
Layers & wrappings that support and surround organs
Provides routes for blood vessels, lymphatics & nerves
70
What is Marfan syndrome?
Connective tissue disorder
Inherited condition (autosomal dominant)
Abnormal fibrillin-1 protein
Manifestations:
skeletal:
tall – long limbs & fingers – loose joints – …
ocular:
lens dislocation
cardiovascular:
heart valve abnormality – aortic dissecting aneurysm
71
What is muscle tissue?
It is specialized for contraction?
There are three types:
skeletal muscles:
body muscles responsible for movement
cardiac muscles:
only in the heart
smooth muscles:
walls of hollow, contracting organs
(e.g., blood vessels - urinary and digestive tracts)
72
What are the three classifications of muscles?
Striated (banded) or Nonstriated (not banded = smooth)
Voluntary (consciously) or Involuntary (automatically)
Mononucleated or Multinucleated
73
What are skeletal muscle cells?
Started, voluntary, and multinucleated.
Long and thin.
Produced by stem cells.
They do not divide because they have no centrioles.
Can be up to a meter long.
74
What cardiac muscles cells (Cardiomyocytes)?
Striated, involuntary, and mono-nucleated.
Branching, connected at intercalated discs.
Do not divide.
Regulated by pacemaker cells.
75
What are smooth muscle cells?
Nonstraited, involuntary, and mononucleated.
Small and tapered, spindle shaped.
Can divide and regenerate.
76
What is neural (nervous) tissue?
Specialized for conducting electrical impulses
Rapidly senses internal or external environment
Processes information and controls responses
98% in the brain & spinal cord
77
What are types of neural cells?
Neurons:
functional nerve cells
perform electrical communication
do not divide (no centrioles)
Neuroglia:
support cells
repair and supply nutrients to neurons
78
What is the purpose of body membranes?
Physical barriers
Line or cover portions of the body
Consist of:
epithelium
areolar connective tissues (lamina propria)
79
What are the four types of membranes?
Mucous
Serous
Cutaneous (skin)
Synovial
80
What is the mucous membrane (mucosa)?
Lines passageways with external connections.
Digestive, respiratory, urinary, and reproductive tracts.
Structure:
epithelial surfaces:
moist to reduce friction and
facilitate absorption and excretion
connective tissue (lamina propria):
areolar tissue
81
What is the serous membrane?
Line cavities not open to the outside.
Thin but strong.
There are two layers; parietal layer which lines the cavity, and the visceral layer which covers organs, there is fluid in between to reduce friction.
82
What are the different cavities and serous membranes?
Pleura; covers lungs.
Pericardium; covers heart.
Peritoneum; covers abdominal organs.
83
What is the cutaneous membrane (skin)?
Outer suave of the body.
Thick, waterproof and dry.
Structure: Epithelium, areolar tissue, dense irregular CT.
84
What is the synovial membrane?
Line articulating joint cavities.
Produce synovial fluid (lubricant).
Protect bone ends.
Lack true epithelium.
85
How do tissue injuries repair?
Tissues respond to injuries to maintain homeostasis.
Cells restore homeostasis with two processes; inflammation and regeneration (healing).
86
What is inflammation?
Tissue's first response to injury.
Triggered by trauma and infection.
Manifestation of inflammatory repose as pain, tenderness, swelling, redness, and hotness.
87
What is the first response in the inflammatory process?
Damaged cells release chemicals (e.g., PGs – K+) in the interstitial fluid
Cells break down:
lysosomes release enzymes
tissue destruction = necrosis
necrotic tissue & cellular debris = pus
abscess = pus trapped in an enclosed area
Mast cells release chemicals mediators (e.g., histamine – heparin)
Dilation of blood vessels (vasodilation)
88
What is the second response in the inflammatory process?
Vasodilation:
increases blood circulation in the area
warmth and redness
brings more nutrients and O2
removes wastes
Plasma diffuses into the area:
swelling and pain
Phagocytic white blood cells:
clean up the area
89
What is the regeneration (healing) process?
Starts when injury or infection is cleaned up
Depends on cell type:
epithelial & connective tissue:
regenerate well
cardiac cells & neurons:
do not regenerate
wounds heal by connective tissue scar
New cells:
produced by stem cells
migrate into area
Fibroblasts move into necrotic area:
lay down collagen fibers (scar tissue)
90
What are the effects of aging on tissues?
Thinning of epithelial and connective tissues
Increased bruising and impaired healing
Increased bone brittleness and fractures
Joint pain and degeneration
Muscle wasting and weakness
Cardiovascular disease
Mental deterioration
