Chapter 4 Flashcards

(89 cards)

1
Q

Four Basic Types of Tissues

A
  1. Epithelial Tissue
  2. Connective Tissue
  3. Muscle Tissue
  4. Neural Tissue
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2
Q

Epithelial Tissue Overview

A
  • Covers body tissue
  • Lines cavities
  • Lines tubular structures
  • Serves essential functions
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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

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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

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5
Q

Four essential functions of epithelia

A
  1. Provide physical protection
  2. Control permeability
  3. Provide sensation
  4. Produce specialized secretions (glandular epithelium)
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6
Q

Gland Cells

A
  • Epithelial cells produce secretions

- Classified by where secretions discharged

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7
Q

Exocrine

A

Secretions discharged onto surface of epithelium

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8
Q

Endocrine

A

Secretions (called hormones) released into surround tissue fluid and blood

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9
Q

Intercellular Connections

A

Allow firm attachment to basement membrane and to adjacent epithelial cells

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10
Q

Attached materials

A
  • Transmembrane proteins called cell adhesion molecules (CAMs)
  • Proteoglycans
  • Blind CAMs to each other and to extracellular materials
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11
Q

Three Common Cell Junctions

A
  1. Tight Junctions
  2. Gap Junctions
  3. Desmosomes
    Hemidesmosomes attach epithelial cells to a basement membrane and appear as almost “half” desmosomes
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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

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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

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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
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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)
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16
Q

Cell Layers

A

Simple epithelium

Stratified epithelium

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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
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18
Q

Stratified Epithelium

A
  • Multiple layers of cells
  • Provides greater protection
  • Found in areas exposed to mechanical or chemical stress
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19
Q

Squamous Epithelium

A

Side view: thin and flat

Top view: fried eggs laid side by side

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20
Q

Cuboidal Epithelium

A

Side view: square with large round nucleus in center

Top view: hexagonal boxes

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21
Q

Columnar Epithelium

A

Side view: rectangular with nuclei near base

Top view: Hexagonal boxes

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22
Q

Stratified Cuboidal Epithelium

A
  • Relatively rare

- Found in ducts of sweat glands and mammary glands

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23
Q

Stratified columnar epithelium

A
  • Relatively rare
  • found in parts of pharynx, epiglottis, anus, urethra
  • Only superficial cells are columnar
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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
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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
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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
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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
30
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
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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
36
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
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Functions of connective tissue
- Support and protection - Transportation of materials - Storage of energy reserves - Defense of the body
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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
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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
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Collagen fibers
- long, straight, unbranched - Strong, but flexible - Most common type of fibers
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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
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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
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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
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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
54
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
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Cartilage
Firm gel matrix with embedded fibers
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Chondrocytes (cartilage cells)
-Contained in small pockets (lacunae)
58
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
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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
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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)
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Periosteum
Covers bone surfaces Composed of: Fibrous outer layer Cellular inner layer
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Tissue Membranes
-Are physicals barriers -Line or cover portions of the body Consists of: An epithelium Supporting connective tissues
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Four types of tissue membranes
1. Mucous membranes 2. Serous membranes 3. Cutaneous membrane 4. Synovial membrane
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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
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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
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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
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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
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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
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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
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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
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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
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Cell Body
Contains the nucleus
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Dendrites
- Numerous short branches extending from the cell body | - Receive incoming signals
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Axon (nerve fiber)
- Long, thin extension of the cell body | - Carries outgoing electrical signals to their destination
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Response to Tissue Injury
- Tissues respond to injuries to maintain homeostasis - Cells restore homeostasis with two processes 1. Inflammation 2. Regeneration
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Inflammatory Response
``` -The tissue’s first response to injury Signs and symptoms include: -Swelling -Heat -Redness -Pain ```
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Inflammatory Response Triggers
- Can be triggered by: - Trauma (physical injury) - Impact, abrasion, chemical irritation - Infection (the presence of harmful pathogens) - Extreme temperatures
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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
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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
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Effects of aging on tissues
- Body’s ability to repair damaged tissue declines | - Cancer more likely to occur
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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
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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