Chapter 4 Flashcards
(89 cards)
1
Q
Four Basic Types of Tissues
A
- Epithelial Tissue
- Connective Tissue
- Muscle Tissue
- Neural Tissue
2
Q
Epithelial Tissue Overview
A
- Covers body tissue
- Lines cavities
- Lines tubular structures
- Serves essential functions
3
Q
Characteristics of Epithelial Tissue
A
-Cell bound closely together
Free (apical) surface
-Attached to underlying connective tissue by basement membrane
-Avascular (lacks blood vessels)
-Continual replacement or regulation of cells
4
Q
Location of Epithelial Tissue
A
Cover external and internal body surfaces
-Examples: skin, internal passageways (digestive, urinary. respiratory, reproductive tracts)
-Form selective barriers
Line internal cavities and passageways
-Examples: Cavities around lungs, heart
-prevent friction
5
Q
Four essential functions of epithelia
A
- Provide physical protection
- Control permeability
- Provide sensation
- Produce specialized secretions (glandular epithelium)
6
Q
Gland Cells
A
- Epithelial cells produce secretions
- Classified by where secretions discharged
7
Q
Exocrine
A
Secretions discharged onto surface of epithelium
8
Q
Endocrine
A
Secretions (called hormones) released into surround tissue fluid and blood
9
Q
Intercellular Connections
A
Allow firm attachment to basement membrane and to adjacent epithelial cells
10
Q
Attached materials
A
- Transmembrane proteins called cell adhesion molecules (CAMs)
- Proteoglycans
- Blind CAMs to each other and to extracellular materials
11
Q
Three Common Cell Junctions
A
- Tight Junctions
- Gap Junctions
- Desmosomes
Hemidesmosomes attach epithelial cells to a basement membrane and appear as almost “half” desmosomes
12
Q
The Epithelial Surface
A
-Apical surface is exposed to an internal or external environment
Often has specialized structures, such as:
-Microvilli to increase surface area
-Cilia to move materials across the surface
Example: ciliated epithelium lining respiratory tract
13
Q
The Basement Membrane
A
-Lies between epithelium and underlying connective tissue
-Noncellular network of protein fibers
Functions:
-Provides strength
-Resists distortion
-Acts as a barrier to proteins and other large molecules
14
Q
Epithelial Renewal and Repair
A
- Require continual renewal and repair
- Accomplished by continuous division of unspecialized stem cells (germinative cells)
- Occurs in deepest levels near basement membrane
15
Q
Classification of Epithelia
A
Determined by:
- Number of layers of cells
- simple (single layer)
- Stratified (multiple layers)
- Shape of exposed cells
- Squamous (flat)
- Cuboidal (square)
- Columnar (rectangular)
16
Q
Cell Layers
A
Simple epithelium
Stratified epithelium
17
Q
Simple Epithelium
A
- Single layer of cells covering basement membrane
- Fragile
- Lines internal compartments and passageways
- Common in places where secretion and absorption take place
18
Q
Stratified Epithelium
A
- Multiple layers of cells
- Provides greater protection
- Found in areas exposed to mechanical or chemical stress
19
Q
Squamous Epithelium
A
Side view: thin and flat
Top view: fried eggs laid side by side
20
Q
Cuboidal Epithelium
A
Side view: square with large round nucleus in center
Top view: hexagonal boxes
21
Q
Columnar Epithelium
A
Side view: rectangular with nuclei near base
Top view: Hexagonal boxes
22
Q
Stratified Cuboidal Epithelium
A
- Relatively rare
- Found in ducts of sweat glands and mammary glands
23
Q
Stratified columnar epithelium
A
- Relatively rare
- found in parts of pharynx, epiglottis, anus, urethra
- Only superficial cells are columnar
24
Q
Pseudostratified columnar epithelium
A
- Appears layered form multiple positions of nuclei, but is really only one cell layer thick
- all cells contact basement membrane
- cells typically have cilia
25
Stratified epithelium
- Appearance changes with stretching
- In empty bladder, outermost cells appear cuboidal
- In full bladder, outermost cells appear flattened
26
Exocrine Glands
- Discharge secretions though a duct or tube
| - Tube empties onto an external or internal surface
27
Endocrine Glands
- Ductless glands
| - Release hormones directly into blood or tissue fluids
28
What are the three modes of secretion that exist for exocrine glands
1. Merocrine secretion
2. Apocrine secretion
3. Holocrine secretion
29
Merocrine Secretion
-Product is released from secretory vesicles by exocytosis
-Most common mode of exocrine secretion
Example: salivary glands
Mucin (one product secreted) mixes with water to produce mucus
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Apocrine Secretion
-Secretory vesicles packed into outer portion of cytoplasm
-Release involves shedding of some cytoplasm along with vesicles
-gland cell grows and repairs before additional releases
Example: mammary glands
31
Holocrine Secretion
-Entire call packed with vesicles
-Cells burst
-Releasing secretion
-Killing gland cells
-Gland cells replaced by stem cells
Example: sebaceous glands
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Types of secretion: Serous Glands
Watery secretions with enzymes
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Types of secretion: Mucous Glands
Secrete mucins that form mucus
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Types of secretion: Mixed glands
Both serous and mucous
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Connective Tissue
- Provides a protective structural framework for other tissue types
- Most diverse tissue of the body
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Connective tissue components
1. Specialized cells
2. Extracellular protein fibers
3. Fluid extracellular ground substance
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Characteristics of connective tissue
- Cells surrounded by matrix
- formed form extracellular fibers and ground substance
- accounts for majority of tissue volume
- Never exposed to the outside environment
- Many connective tissues are highly vascular
- Contain sensory receptors
38
Functions of connective tissue
- Support and protection
- Transportation of materials
- Storage of energy reserves
- Defense of the body
39
Three Major Types of Connective Tissue
1. Connective tissue proper
2. Fluid connective tissues
3. Supporting connective tissues
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Connective Tissue Proper
-Many cell types
-Matrix with extracellular
Examples:
Tissue under the skin
Fatty Tissue
Tendons and
ligaments
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Fibroblasts
- Always present in connective tissue proper
- Most abundant permanent cells in connective tissue proper
- Produce connective tissue fibers and ground substance
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Fibrocytes
- differentiate from fibroblasts
| - Maintain connective tissue fibers
43
Macrophages
- Large phagocytic cells
- Scattered throughout the matrix
- Phagocytize damaged cells or pathogens that enter the tissue
- Release chemicals that mobilize the immune system
44
Fat Cells ( adipocytes or adipose cells)
- Permanent residents
- Each cell contains large lipid droplet
- number of fat cells vary
45
Mast Cells
- Small, mobile cells often found near blood vessels
- Cytoplasm is packed with granules
- Filled with histamine and heparin
- Released to begin body's defensive activities after an injury or infection
46
What are the 3 basic types of connective tissue fibers?
1. Collagen fibers
2. Elastic fibers
3. Reticular fibers
47
Collagen fibers
- long, straight, unbranched
- Strong, but flexible
- Most common type of fibers
48
Elastic fibers
- Branched and wavy
- Return to their original length after stretching
- contain the protein elastin
49
Reticular fibers
- Made of same protein subunits as collagen fibers, but arranged differently
- Thinner then collagen fibers
- Form branching, interwoven framework in various organs
- least common type of fibers
50
Ground substance
- Fills spaces between cells and surrounds connective tissue fibers
- Consistency in normal connective tissue proper
- Clear, colorless, and syrupy
- Slows movement of pathogens
51
Loose connective tissues
-"packing materials" of the body
-More ground substance, fewer fibers
Functions
-Fills space between organs and provide cushioning
-Support epithelia
-Anchor blood vessels and nerves
-Store lipids
52
Dense connective tissue
-Tough, strong, and durable
-More fibers (mostly collagen) less ground substance
-Resist tension and distortion
-Interconnect bones and muscles
Tendons- Attach skeletal muscle to bone
Ligaments- Connect bone to bone
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Blood and Lymph
- Distinct cell types in a fluid matrix with dissolved proteins
- Watery matrix in blood is plasma
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Cell types in blood
- Red Blood cells
- White Blood cells
- Platelets (cell fragments)
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Supporting Connective Tissues
-Provide strong framework that supports rest of the body
-Matrix contains numerous fibers
-In some, also contain deposits of solid calcium salts
Tissues contain
-Cartilage
-Bones
56
Cartilage
Firm gel matrix with embedded fibers
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Chondrocytes (cartilage cells)
-Contained in small pockets (lacunae)
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Cartilage Structure
- Avascular (no blood supply)
- Chondrocytes obtain nutrients and eliminate wastes by diffusion through matrix
- Limited repair ability
- Covered by perichondrium
- Outer, fibrous layer (for strength)
- Inner, cellular layer (for growth and maintenance)
59
Hyaline Cartilage
-Most common types of cartilage
-Matrix with closely packed collagen fibers
-Provides tough, somewhat flexible support
-Reduces friction between bones
Locations:
-Bone surfaces in synovial joints
-Connecting ribs to sternum
-Conducting passageways of respiratory tract (trachea and bronchi)
-Nasal septum
60
Elastic cartilage
-Contains numerous elastic fibers
-Resilient and flexible
locations
-Externa ear (auricle or pinna)
-Epiglottis
-Auditory tube
61
Fibrocartilage
-Little ground substance
-Matrix mostly densely woven collagen fibers
-Extremely durable and tough
-Resists compression, absorbs socks, prevents bone-to-bone contact
Locations
-Within knee joints
-Between pubic bones
-Forms intervertebral discs
62
Bone or osseous tissue
- Very small volume of ground substance
- Matrix of hard calcium compounds and flexible collagen fibers
- Strong (hard calcium compounds)
- Resists shattering (flexible collagen fibers)
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Bone cells or osteocytes
- Contained in lacunae (small pockets)
- Arranged around central canals within matrix
- Obtain nutrients through cytoplasmic extensions running through branching network within matrix (canaliculi)
64
Periosteum
Covers bone surfaces
Composed of:
Fibrous outer layer
Cellular inner layer
65
Tissue Membranes
-Are physicals barriers
-Line or cover portions of the body
Consists of:
An epithelium
Supporting connective tissues
66
Four types of tissue membranes
1. Mucous membranes
2. Serous membranes
3. Cutaneous membrane
4. Synovial membrane
67
Mucous Membranes
-Also known as mucosae
-Line passageways that open to the exterior
Examples: digestive, respiratory, urinary, and reproductive tracts
-Epithelial surfaces kept moist at all times (typically by mucous secretions)
-Type of epithelium varies
-Connective tissue layer composed of areolar tissue
-Layer called lamina propria
68
Serous Membranes
-Line cavities not open to the outside
-Simple epithelium supported by areolar tissue
Consists of two portions
Parietal - lining the inner surface of the cavity
Visceral (serosa) - covering outer surface of organs in the body cavity
-Watery serous fluid reduces friction between parietal and visceral surfaces
69
Three Serous Membranes
1. Pleura
- Lines pleural cavities
- Covers lungs
2. Peritoneum
- Lines peritoneal cavity
- Covers abdominal organs
3. Pericardium
- Lines pericardial cavity
- Covers heart
70
Cutaneous Membrane
- The skin
- Covers the surface of the body
- Epithelium is stratified squamous epithelium
- Connective tissue consists of areolar tissue and underlying dense irregular connective tissue
- Thick, relatively waterproof, and usually dry
71
Synovial Membranes
-Line freely moving, articulating joint cavities
-Consist primarily of areolar tissue
-Incomplete layer of epithelial tissue
-Protect the ends of bones
-Produce viscous synovial fluid
-Lubricates the joint and allows smooth
movement
72
Muscles Tissue
- Specialized for contraction
| - Contract due to interactions between filaments of proteins myosin and actin
73
Three types of muscle tissue in the body
1. Skeletal
2. Cardiac
3. Smooth
74
Skeletal Muscle Tissue
- Moves or stabilizes position of the skeleton
- Contains large, multinucleated cells
- Long and slender individual cells called muscle fibers
- New muscle fibers produced by division of stem cells
- Myosin and actin arranged in repeating patterns, giving cells striated appearance
- Under voluntary control
75
Cardiac Muscle Tissue
- Found only in the heart
- Striated involuntary muscle
- Typical cell or cardiocyte smaller than skeletal muscle fiber
- Usually single nucleus per cell
- Cells show extensive branching and interconnections at intercalated discs
- Allows efficient coordinated contraction
- Very limited ability to repair
76
Smooth Muscle Tissue
Found:
- In walls of blood vessels
- Around hollow organs such as the urinary bladder
- Around the respiratory, digestive, and reproductive tracts
- Small, slender cells tapered at the ends
- Nonstriated involuntary muscle
- Can regenerate after injury
77
Neural Tissue
- Also called nervous or nerve tissue
- Specialized for transmitting electrical impulses
- Most concentrated in brain and spinal cord
- Rapidly senses internal or external environment
- Processes information and controls responses
78
Two kinds of Neural Cells
1. Neurons
- Nerve cells
- Communicate through electrical events
- Very limited ability to repair after injury
2. Neuroglia
- Supporting cells
- Provide physical support for neural tissue
- Maintain chemical composition of neural tissue fluids
- Supply nutrients to neurons
- Defend tissue from infection
79
Cell Body
Contains the nucleus
80
Dendrites
- Numerous short branches extending from the cell body
| - Receive incoming signals
81
Axon (nerve fiber)
- Long, thin extension of the cell body
| - Carries outgoing electrical signals to their destination
82
Response to Tissue Injury
- Tissues respond to injuries to maintain homeostasis
- Cells restore homeostasis with two processes
1. Inflammation
2. Regeneration
83
Inflammatory Response
```
-The tissue’s first response to injury
Signs and symptoms include:
-Swelling
-Heat
-Redness
-Pain
```
84
Inflammatory Response Triggers
- Can be triggered by:
- Trauma (physical injury)
- Impact, abrasion, chemical irritation
- Infection (the presence of harmful pathogens)
- Extreme temperatures
85
Inflammatory Response Process
- Mast cells are stimulated
- Chemicals (histamine and heparin) released
- Local blood vessels dilated (enlarged) and made more permeable
- Increased blood flow to injured region
- Red, warm to touch, swollen
- Increases delivery of required materials
- Speeds removal of waste products and toxins
86
Regeneration
-Second phase following injury
-Damaged tissues replaced or repaired
-Fibroblasts produce scar tissue
-Permanent replacement of normal tissue called fibrosis
-Different tissues vary in ability to regenerate after injury
Good regeneration – epithelial tissue, most connective tissue, smooth muscle
Poor regeneration – cardiac muscle, skeletal muscle, cartilage, neural tissue
87
Effects of aging on tissues
- Body’s ability to repair damaged tissue declines
| - Cancer more likely to occur
88
Aging and Tissue Structure
- Speed and effectiveness of tissue repair decrease with age due to:
- Slower rate of energy consumption (metabolism)
- Hormonal alterations
- Reduced physical activity
89
Age-related Tissue Changes
- Thinning of epithelium
- Connective tissue becomes more fragile
- Bones become more brittle
- Increasing incidence of osteoporosis
- Thinner, less resilient cartilage
- Increased cardiovascular disease
- Deterioration in mental functioning
- Aging and Cancer Incidence
- Cancer rates increase with age
- 25% of all people in the United States develop cancer
- Cancer is the #2 cause of death in the United States
- Over 500,000 deaths per year
- Mutations due to chemical exposure and environmental factors account for 70–80% of cancer cases
- Cigarette smoke causes 40% of these cancers
