tissue Flashcards
(133 cards)
1
Q
What are tissues?
A
Groups of cells that are similar in structure and perform a common or related function.
2
Q
List the four primary tissue types.
A
- Epithelial tissue
- Connective tissue
- Muscle tissue
- Nervous tissue
3
Q
What is the primary function of epithelial tissue?
A
Covers body surfaces.
4
Q
What is the primary function of connective tissue?
A
Supports the body.
5
Q
What is the primary function of muscle tissue?
A
Moves the body.
6
Q
What is the primary function of nervous tissue?
A
Controls body functions.
7
Q
What is histology?
A
The study of tissues.
8
Q
What do multicellular organisms rely on for cell function?
A
Tight cell communities that work together.
9
Q
What is cell specialization?
A
Different cell types perform specific functions to maintain homeostasis.
10
Q
True or False: Epithelial tissue is avascular but innervated.
A
True.
11
Q
What are the two forms of epithelial tissue?
A
- Covering and lining epithelium
- Glandular epithelium
12
Q
What are the six functions of epithelial tissue?
A
- Protection
- Absorption
- Filtration
- Excretion
- Secretion
- Sensory reception
13
Q
What does apical-basal polarity refer to in epithelial tissue?
A
The presence of two different surfaces: apical (exposed) and basal (attached to connective tissue).
14
Q
What are microvilli?
A
Fingerlike extensions of the plasma membrane that increase surface area.
15
Q
What is the basal lamina?
A
A thin supporting sheet adjacent to the basal surface of an epithelium.
16
Q
What are tight junctions?
A
Connections that prevent substances from leaking between epithelial cells.
17
Q
What is the basement membrane?
A
A structure that supports the epithelial sheet and consists of the basal lamina and reticular lamina.
18
Q
What is the regenerative capacity of epithelial tissue?
A
Epithelial tissue has a high capacity for regeneration.
19
Q
What are simple epithelia?
A
Epithelia that consist of a single cell layer.
20
Q
What are stratified epithelia?
A
Epithelia composed of two or more cell layers stacked on top of each other.
21
Q
What are the three common shapes of epithelial cells?
A
- Squamous
- Cuboidal
- Columnar
22
Q
Where is simple squamous epithelium typically found?
A
- Kidney glomeruli
- Air sacs of lungs
- Lining of heart, blood vessels, and lymphatic vessels
- Serosae
23
Q
What is the function of simple cuboidal epithelium? and where they found
A
Secretion and absorption. Kidney tubules; ducts and secretory portions of small glands; ovary surface
24
Q
Where is simple columnar epithelium found?
A
- Lining of the digestive tract
- Gallbladder
- Excretory ducts of some glands
- Small bronchi and uterine tubes
25
What is pseudostratified columnar epithelium?
Epithelial tissue where cells vary in height but all rest on the basement membrane.
26
What type of epithelium secretes mucus and has cilia on its free surface?
Simple columnar epithelium
## Footnote
Cilia help move substances or cells through an internal passageway.
27
What is pseudostratified columnar epithelium?
A type of epithelium where all cells rest on the basement membrane, but only the tallest reach the free surface, creating a false impression of multiple layers.
## Footnote
It often contains ciliated cells and goblet cells.
28
What is the function of endothelium?
Provides a slick, friction-reducing lining in lymphatic vessels and cardiovascular system.
## Footnote
Capillaries consist exclusively of endothelium.
29
What type of epithelium is found in serous membranes?
Mesothelium
## Footnote
It lines the ventral body cavity and covers its organs.
30
What are the primary functions of simple cuboidal epithelium?
Secretion and absorption.
## Footnote
It forms the walls of the smallest ducts of glands and many kidney tubules.
31
What type of epithelium lines the digestive tract from the stomach through the rectum?
Simple columnar epithelium
## Footnote
It consists of a single layer of tall, closely packed cells.
32
Describe the structure of stratified squamous epithelium.
Thick epithelium composed of several layers with surface cells that are flattened (squamous).
## Footnote
Basal cells are cuboidal or columnar and metabolically active.
33
What is the function of transitional epithelium?
Allows stretching and permits distension of urinary organs.
## Footnote
It lines the ureters, bladder, and part of the urethra.
34
What distinguishes endocrine glands from exocrine glands?
Endocrine glands are ductless and secrete hormones directly into the bloodstream.
## Footnote
Exocrine glands have ducts and secrete products onto body surfaces or cavities.
35
What is the primary role of stratified epithelia?
Protection
## Footnote
They are more durable than simple epithelia and regenerate from below.
36
What are the characteristics of unicellular glands?
They consist of one cell and are typically mucous cells or goblet cells.
## Footnote
They are found among columnar cells in epithelial linings.
37
What is the secretion process for exocrine glands?
They secrete products onto body surfaces or into body cavities via ducts.
## Footnote
Unicellular glands secrete directly, while multicellular glands use ducts.
38
Fill in the blank: Glands may be classified as _______ or exocrine based on where they release their product.
endocrine
39
What are the three types of multicellular exocrine glands based on mode of secretion?
* Merocrine
* Holocrine
* Apocrine
## Footnote
Most exocrine glands are merocrine.
40
What is the structural classification of multicellular exocrine glands based on duct structure?
* Simple (unbranched)
* Compound (branched)
## Footnote
They can also be classified by their secretory units as tubular, alveolar, or tubuloalveolar.
41
What is the function of goblet cells?
To produce mucin, which forms mucus when dissolved in water.
## Footnote
Goblet cells are a type of unicellular exocrine gland.
42
What is the appearance of transitional epithelium when the organ is distended with urine?
It appears to thin from about six cell layers to as few as three, with dome-like apical cells flattening.
## Footnote
This allows for greater volume of urine to flow through.
43
What are the two basic parts of multicellular exocrine glands?
An epithelium-derived duct and a secretory unit (acinus)
## Footnote
The secretory unit consists of secretory cells.
44
How can multicellular exocrine glands be classified?
By structure and by mode of secretion
## Footnote
Classification includes simple and compound duct structures.
45
What is an example of a simple tubular secretory structure?
Intestinal glands
## Footnote
These glands have a non-branching duct.
46
What is an example of a compound tubular secretory structure?
Duodenal glands of the small intestine
## Footnote
These glands have a branching duct.
47
What type of gland is a sebaceous gland classified as?
Holocrine gland
## Footnote
Holocrine glands release their entire secretory cell contents.
48
What distinguishes holocrine glands from merocrine glands?
Holocrine glands accumulate products until they rupture; merocrine glands secrete via exocytosis
## Footnote
Sebaceous glands are true examples of holocrine glands.
49
What are the major functions of connective tissue?
* Binding and supporting
* Protecting
* Insulating
* Storing reserve fuel
* Transporting substances within the body
## Footnote
Connective tissue plays crucial roles in the body beyond just connecting parts.
50
What are the four main classes of connective tissue?
* Connective tissue proper
* Cartilage
* Bone
* Blood
## Footnote
Each class has distinct structural and functional characteristics.
51
What are the common characteristics of connective tissue?
* Extracellular matrix
* Common origin from mesenchyme
## Footnote
The extracellular matrix is non-living and separates living cells.
52
What are the three main components of connective tissue?
* Ground substance
* Fibers
* Cells
## Footnote
These components together form the extracellular matrix.
53
What type of fibers are primarily found in connective tissue?
* Collagen fibers
* Elastic fibers
* Reticular fibers
## Footnote
Collagen fibers provide strength, while elastic fibers allow for stretch.
54
What is the primary function of collagen fibers?
To provide high tensile strength to the matrix
## Footnote
Collagen fibers are stronger than steel fibers of the same size.
55
What is the role of elastic fibers in connective tissue?
To allow tissues to stretch and recoil
## Footnote
Elastic fibers are found in tissues requiring elasticity, such as skin and blood vessels.
56
What is ground substance in connective tissue?
The unstructured material filling the space between cells and containing fibers
## Footnote
It acts as a molecular sieve for nutrients and dissolved substances.
57
What are the three components of ground substance?
* Interstitial fluid
* Cell adhesion proteins
* Proteoglycans
## Footnote
These components help connect cells and trap water in the matrix.
58
What are adipocytes commonly known as?
Fat cells
## Footnote
They store energy in the form of fat.
59
What is Marfan syndrome?
An inherited disorder affecting elastic fibers, leading to overgrowth and instability of tissues
## Footnote
Symptoms may not appear until adulthood.
60
What are macrophages in connective tissue?
Large, irregularly shaped cells that devour foreign materials and dead tissue
## Footnote
They play a critical role in the immune system.
61
What is the embryonic tissue from which all connective tissues arise?
Mesenchyme
## Footnote
Mesenchyme differentiates into all types of mature connective tissues.
62
How do fibroblasts differ from fibrocytes?
Fibroblasts are immature, actively mitotic cells; fibrocytes are mature and maintain the matrix
## Footnote
Fibroblasts secrete the ground substance and fibers.
63
What type of connective tissue is blood classified as?
Fluid tissue
## Footnote
Blood does not have fibers and serves to transport substances throughout the body.
64
What is a hematopoietic stem cell?
A type of stem cell that is not located in blood tissue and does not make plasma.
65
What are adipocytes commonly known as?
Fat cells.
66
What is the role of mast cells in connective tissue?
They detect foreign microorganisms and initiate local inflammatory responses.
67
What chemicals do mast cells contain that mediate inflammation?
* Heparin
* Histamine
68
What is the most widely distributed connective tissue in the body?
Areolar connective tissue.
69
List the functions of areolar connective tissue.
* Supporting and binding other tissues
* Holding body fluids
* Defending against infection
* Storing nutrients as fat
70
What type of connective tissue is characterized by a loose arrangement of fibers?
Areolar connective tissue.
71
What is the predominant cell type in areolar connective tissue?
Fibroblasts.
72
What is adipose tissue primarily composed of?
Adipocytes that account for 90% of its mass.
73
What is the primary function of adipose tissue?
Provides reserve food fuel, insulates against heat loss, supports and protects organs.
74
Where does adipose tissue typically accumulate?
* Subcutaneous tissue
* Around kidneys
* Behind eyeballs
* In abdomen and hips
75
What distinguishes white fat from brown fat?
White fat stores nutrients while brown fat generates heat from lipid fuels.
76
What type of connective tissue forms a soft internal skeleton that supports other cell types?
Reticular connective tissue.
77
What is the primary function of dense regular connective tissue?
Attaches muscles to bones or to muscles and withstands great tensile stress.
78
What are the three varieties of dense connective tissue?
* Dense regular
* Dense irregular
* Elastic
79
What is the main feature of dense irregular connective tissue?
Bundles of collagen fibers arranged irregularly, running in all directions.
80
Where is dense irregular connective tissue commonly found?
* Dermis of the skin
* Fibrous capsules of organs and joints
81
What is hyaline cartilage known for?
Being the most abundant cartilage in the body, providing firm support with some pliability.
82
Where is hyaline cartilage found?
* Ends of long bones
* Tip of the nose
* Connects ribs to sternum
* Supports respiratory system passages
83
What is the role of chondroblasts in cartilage?
Produce new matrix until the skeleton stops growing.
84
What is the primary characteristic of elastic cartilage?
Contains many more elastic fibers than hyaline cartilage.
85
What is cartilage's primary feature regarding its vascularity?
Cartilage is avascular and receives nutrients by diffusion.
86
What is the matrix of cartilage primarily composed of?
GAGs, chondroitin sulfate, hyaluronic acid, and collagen fibers.
87
What percentage of cartilage is water?
Up to 80%.
88
What are chondrocytes?
Mature cartilage cells found in lacunae.
89
Fill in the blank: Adipose tissue constitutes _______ of an average person's body weight.
18%
90
What is the predominant cell type in growing cartilage?
Chondroblasts
## Footnote
Chondroblasts produce new matrix until the skeleton stops growing at the end of adolescence.
91
What are mature cartilage cells called?
Chondrocytes
## Footnote
Chondrocytes are typically found in small groups within cavities called lacunae.
92
What is the function of hyaline cartilage?
Supports and reinforces; serves as resilient cushion; resists compressive stress.
93
Where is hyaline cartilage located?
* Forms most of the embryonic skeleton
* Covers the ends of long bones in joint cavities
* Forms costal cartilages of the ribs
* Cartilages of the nose, trachea, and larynx.
94
What is the main characteristic of elastic cartilage?
Similar to hyaline cartilage, but more elastic fibers in matrix.
95
What is the function of fibrocartilage?
Tensile strength allows it to absorb compressive shock.
96
Where is fibrocartilage found?
* Intervertebral discs
* Pubic symphysis
* Discs of knee joint.
97
What is the main function of bone (osseous tissue)?
Supports and protects; provides levers for the muscles to act on; stores calcium and other minerals and fat; marrow inside bones is the site for blood cell formation.
98
What type of connective tissue is blood classified as?
Atypical connective tissue.
99
What are the two major cell types in nervous tissue?
* Neurons
* Supporting cells (glial cells or neuroglia).
100
What is the primary function of neurons?
Generate and conduct nerve impulses.
101
What is the structure of skeletal muscle?
Long, cylindrical, multinucleate cells with obvious striations.
102
What is the function of cardiac muscle?
Propels blood into circulation; involuntary control.
103
Where is smooth muscle primarily located?
Mostly in the walls of hollow organs.
104
What are the three types of muscle tissue?
* Skeletal muscle
* Cardiac muscle
* Smooth muscle.
105
What is the cutaneous membrane?
An organ system consisting of a keratinized stratified squamous epithelium (epidermis) attached to a thick layer of connective tissue (dermis).
106
What type of membranes line all body cavities that open to the outside?
Mucous membranes (mucosae).
107
What is the characteristic of mucous membranes?
They are wet or moist membranes bathed by secretions.
108
What are the visible structures formed during blood clotting?
Fibers of blood are soluble protein molecules that precipitate.
109
What is the consequence of aging cartilage?
Cartilage tends to calcify or ossify, leading to poorly nourished chondrocytes that may die.
110
What is a key characteristic of smooth muscle cells?
Spindle shaped with central nuclei and no striations.
111
What is the role of osteocytes in bone tissue?
Mature bone cells that reside in lacunae within the bone matrix.
112
What is the function of myofilaments in muscle cells?
Bring about movement or contraction.
113
What is a unique feature of cardiac muscle cells?
They connect at specialized junctions called intercalated discs.
114
What is the primary function of blood?
Transports respiratory gases, nutrients, wastes, and other substances.
115
What are mucous membranes?
Mucous membranes, or mucosae, line all body cavities that open to the outside of the body, such as the hollow organs of the digestive, respiratory, and urogenital tracts.
## Footnote
They are moist membranes bathed by secretions.
116
What types of epithelia do most mucosae contain?
Most mucosae contain either stratified squamous or simple columnar epithelia.
## Footnote
The epithelial sheet lies over a layer of areolar connective tissue called the lamina propria.
117
What is the lamina propria?
The lamina propria is a layer of areolar connective tissue that underlies the epithelial sheet in mucosae.
## Footnote
It may rest on a deeper layer of smooth muscle cells in some mucosae.
118
What is the primary function of mucous membranes?
Mucous membranes are often adapted for absorption and secretion.
## Footnote
Many mucosae secrete mucus, but it is not a requirement.
119
What is a cutaneous membrane?
The cutaneous membrane, or skin, covers the body surface.
## Footnote
It serves as a protective barrier for the body.
120
What are serous membranes?
Serous membranes, or serosae, are moist membranes found in closed ventral body cavities.
## Footnote
They consist of a visceral layer and a parietal layer separated by serous fluid.
121
What are the two layers of serous membranes?
The two layers of serous membranes are the visceral layer and the parietal layer.
## Footnote
These layers consist of simple squamous epithelium resting on areolar connective tissue.
122
What is serous fluid?
Serous fluid is a thin, clear fluid that lubricates the surfaces of the parietal and visceral layers of serous membranes.
## Footnote
It contains hyaluronic acid added by mesothelial cells.
123
What are the names of the serous membranes associated with specific organs?
The serous membranes include:
* Pleurae - line the thoracic wall and cover the lungs
* Pericardium - encloses the heart
* Peritoneum - encloses the abdominopelvic viscera.
124
What initiates the tissue repair process?
The tissue repair process is initiated by growth factors released by injured cells.
## Footnote
These factors stimulate cell division and migration.
125
What are the three steps of tissue repair?
The three steps of tissue repair are:
* Inflammation
* Organization
* Regeneration.
126
What occurs during the inflammatory response?
The inflammatory response is a nonspecific reaction that develops quickly wherever tissues are injured.
## Footnote
It makes blood vessels leaky, allowing white blood cells and proteins to enter the injured area.
127
What is granulation tissue?
Granulation tissue is a delicate pink tissue that forms during the healing process, containing capillaries that grow in from nearby areas.
## Footnote
It plays a crucial role in the repair process.
128
What is regeneration in the context of tissue repair?
Regeneration replaces destroyed tissue with the same kind of tissue.
## Footnote
It occurs in tissues with good regenerative capacity.
129
What is fibrosis in tissue repair?
Fibrosis replaces destroyed tissue with scar tissue, which is dense connective tissue.
## Footnote
This often occurs in tissues with poor regenerative capacity.
130
Which tissues have high regenerative capacity?
Tissues with high regenerative capacity include:
* Epithelial tissues
* Bone
* Areolar connective tissue
* Dense irregular connective tissue
* Blood-forming tissue.
131
Which tissues have a weak regenerative capacity?
Tissues with a weak regenerative capacity include:
* Skeletal muscle
* Cartilage.
132
Which tissues have virtually no functional regenerative capacity?
Cardiac muscle and nervous tissue in the brain and spinal cord have virtually no functional regenerative capacity.
## Footnote
They are often replaced by scar tissue.
133
What can happen to scar tissue in muscular organs?
Scar tissue can severely hamper the function of organs like the urinary bladder or heart.
## Footnote
It may reduce internal volume and block substances from moving through hollow organs.
