Chapter 4 Flashcards
Four types of tissue
Epithelial
Connective
Muscle
Neural
- Covers exposed surfaces
- Lines internal passageways
- Forms glands
Epithelial tissue
- Fills internal spaces
- Supports other tissues
- Transports materials
- Stores energy
Connective tissue
- Specialized for contraction
* Skeletal muscle heart muscle and walls of hollow organs
Muscle tissue
Carries electrical signals from one part of the body to another
Neural tissue
Characteristics of epithelia
- Cellularity
- polarity
- attachment
- vascularity
- regeneration
Functions of epithelial tissue
- Provide physical protection
- control permeability
- provides sensation
- produced specialize secretions (granular epithelium)
Types of cell junctions
Tight junctions
gap junctions
desmosomes
- Between two plasma membranes
* adhesion that attaches to terminal Web *prevents passage of water and solutes
Tight junctions
- Allow rapid communication
- Are held together by channel proteins
- allow ions to pass
- Coordinate contractions and heart muscle
Gap junctions
Dense areas and intercellular cemented
- spot desmosomes: tie cells together; allow bending and twisting
- hemisdesmosomes: attach cells to the basal lamina
Desmosomes
Release hormones:
- into interstitial fluid
- no ducts
Endocrine glands
Produce secretions:
onto epithelial surfaces
through ducts
Exocrine glands
Watery secretions
Serous glands
Secrete mucins
Mucous glands
Both serous and mucus
Mixed exocrine glands
3 types of secretions
Serous
Mucous
Mixed exocrine glands
Basic features of connective tissue
Specialized cells
Solid extracellular protein fibers
Fluid extracellular ground substance
*extacellular protein fibers and ground substance makeup the matrix
Classification of connective tissues
- Connective tissue proper (connect and protect/fibroblast and adipocytes)
- Fluid connective tissues (transport/blood and lymph)
- Supporting connective tissues (structural strength/bone and cartilage)
Functions of connective tissue
- est. a structural framework for the body
- Transport fluids and dissolved materials
- Protect delicate organs
- Supporting surrounding and interconnecting other types of tissues
- Storing energy reserves especially in the form of triglycerides
- Defending the body from invading microorganism
The most abundant cell type;
- Found in all connective tissue proper
- Secrete proteins and hyaluronan (cellular cement)
Fibroblasts
The second most abundant cell type;
- Found in all my connective tissue proper
- Maintain the fibers of connective tissue proper
Fibrocytes
Fats cells
Each cells stores a single, large fat droplet
Adipocytes
Stem cells that respond to injury or infections
Differentiate into fibroblasts, microphages, etc.
Mesenchymal cells
Large amoeba-like cells of the immune system
- eat pathogens and damaged cell
- fixed macrophages stay in tissue
- free macrophages migrate
Macrophage
Stimulate inflammation after injury or infection
*release histamine and heparin
Basophils are leukocytes (white blood cells) that also contain histamine and heparin
Mast cells
Specialized immune cells in lymphatic system
(Lymphoid system)
For example lymphocytes may develop into plasma cells ( plasmocytes ) that produce antibodies
Lymphocytes
Phagocytic blood cells
- respond to signals from macrophages and mast cells
- for example neutrophils and eosinophils
Microphages
Synthesize and store the brown pigment melanin
Melanocytes
Three types of connective tissue fibers
Collagen
Reticular
Elastic
- Most common fibers in connective tissue proper
- long straight and unbranched
- strong and flexible
- resist force in one direction
- for example; tendons and ligaments
Collagen fibers
*Network of interwoven fibers (stroma)
*Strong and flexible
*Resist force in many directions
*stabilize functional cells and structures
for example; sheaths about organs
Reticular fibers
- Contain elastin
- branched and wavy
- return to original length after stretching
- for example; elastic ligaments of vertebrate
Elastic fibers
Three types of loose connective tissue
Areolar
Adipose
Reticular
in adults do not divide (hypertrophy)
• Expand to store fat
• Shrink as fats are released
Adipose cells
cells divide and differentiate (hyperplasia)
• To produce more fat cells
• When more storage is needed
Mesenchymal cells
Tightly packed, parallel collagen fibers
• Dense Regular Connective Tissue
attach muscles to bones
Tendons
connect bone to bone and stabilize organs
Ligaments
attach in sheets to large, flat muscles
Aponeuroses
- Watery matrix of dissolved proteins
* Carry specific cell types (formed elements)
Blood and lymph
Formed elements of blood
- Red blood cells (erythrocytes)
- White blood cells (leukocytes)
- Platelets
- Fluid Elements of Connective Tissues
* Extracellular
- Plasma
- Interstitial fluid
- Lymph
Cardiovascular system (blood)
- Arteries
- Capillaries
- Veins
• Lymphatic (lymphoid) system (lymph)
• Lymphatic vessels
- Gel-type ground substance
- Composed of chondrocytes
- For shock absorption and protection
• Cartilage
- Calcified (made rigid by calcium salts, minerals)
* For weight support
• Bone
No blood vessels
• Chondrocytes produce antiangiogenesis factor
Cartilage Structure
- Outer, fibrous layer (for strength)
* Inner, cellular layer (for growth and maintenance)
• Perichondrium
- Strong (calcified calcium salt deposits)
* Resists shattering (flexible collagen fibers)
Bone or Osseous Tissue
• Arranged around central canals within matrix
• Small channels through matrix (canaliculi) access
blood supply
Bone Cells or Osteocytes
- Covers bone surfaces
- Fibrous layer
- Cellular layer
Periosteum
Membranes
- Physical barriers
- Line or cover portions of the body
- Consist of:
- An epithelium
- Supported by connective tissue
Four Types of Membranes
- Mucous membranes (absorb & secret)
- Serous membranes (lubricate)
- Cutaneous membrane (barrier & protect)
- Synovial membranes (cushion)
Specialized for contraction
• Produces all body movement
Muscle Tissue
Three types of muscle tissue
Skeletal muscle tissue
Cardiac muscle tissue
Smooth muscle tissue
• Large body muscles responsible for movement
Skeletal muscle tissue
• Found only in the heart
Cardiac muscle tissue
• Found in walls of hollow, contracting organs (blood
vessels; urinary bladder; respiratory, digestive, and
reproductive tracts)
Smooth muscle tissue
(muscle cells with a banded appearance)
Striated
(not banded; smooth)
Nonstriated
Muscle cells can be controlled (consciously)
voluntarily
Muscle cells can be controlled (automatically)
involuntarily
• Long and thin • Usually called muscle fibers • Do not divide • New fibers are produced by stem cells (myosatellite cells)
Skeletal Muscle Cells
• Called cardiocytes/cardiomyocytes
• Form branching networks connected at intercalated
discs
• Regulated by pacemaker cells
Cardiac Muscle Cells
- Small and tapered
* Can divide and regenerate
Smooth Muscle Cells
- Also called nervous or nerve tissue
- Specialized for conducting electrical impulses
- Rapidly senses internal or external environment
- Processes information and controls responses
Neural Tissue
Two Types of Neural Cells
- Neurons
2. Neuroglia
- Nerve cells
* Perform electrical communication
Neurons
- Supporting cells
* Repair and supply nutrients to neurons
Neuroglia
Cells restore homeostasis with two processes
- Inflammation
2. Regeneration
Signs and symptoms of the inflammatory
response include:
- Swelling
- Redness
- Heat
- Pain
The tissue’s first response to injury
Inflammation = Inflammatory Response
Damaged cells release what 3 chemical signals into the
surrounding interstitial fluid
- Prostaglandins
- Proteins
- Potassium ions
As cells break down:
• Lysosomes release enzymes that destroy the injured cell and
attack surrounding tissues
• Tissue destruction is called necrosis
Injury stimulates mast cells to release these 3 things:
- Histamine
- Heparin
- Prostaglandins
Dilation of blood vessels:
Increases blood circulation in the area
• Causes warmth and redness
• Brings more nutrients and oxygen to the area
• Removes wastes
The Process of Inflammation
- Dilation of blood vessels
- Increases blood circulation in the area
- Causes warmth and redness
- Brings more nutrients and oxygen to the area
- Removes wastes
- Plasma diffuses into the area
- Causes swelling and pain
- Phagocytic white blood cells
- Clean up the area
• Regeneration
• Fibrocytes move into necrotic area
• Lay down collagen fibers
• To bind the area together (scar tissue)
• New cells migrate into area
• Or are produced by mesenchymal stem cells
• Not all tissues can regenerate
• Epithelia and connective tissues regenerate well
• Cardiac cells and neurons do not regenerate (or
regenerate poorly)
Aging and Tissue Structure
• Speed and efficiency of tissue repair decrease with
age, due to:
• Slower rate of energy consumption (metabolism)
• Hormonal alterations
• Reduced physical activity
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
• Environmental chemicals and cigarette smoke cause
cancer