Tissues, a&p test #2

4 types of tissue:

epithelial tissue

connective tissue

muscle tissue

neural tissue

tissues

cells and cell products that work together to perform specific, limited functions

Epithelial tissue:

• Covers exposed surfaces

• Line internal passageways

• Form glands

5 characteristics of epithelial tissue

cellularity, polarity, attachment, avascularity, and regeneration

5 characteristics of epithelial tissue:

CELLULARITY 

Tissue almost entirely cells

5 characteristics of epithelial tissue:

CELLULAR POLARITY

1. Different types of cell membranes on different sides of cell

2. One side of cell (apical side) exposed to environemnt or cavity

   1. Can have cilia or microvilli

3. Other sides attach to cells or membranes

5 characteristics of epithelial tissue:

ATTACHMENT 

1. Base of cell attached to basement membrane 

2. Sides attached to other cells

5 characteristics of epithelial tissue:

AVASCULARITY

1. Lack of blood vessels

2. Nutrients through diffusion or absorption

5 characteristics of epithelial tissue:

REGENERATION

1. High rate of replacement through stem cells 

Intercellular connections:

1.  Connecting large areas of membrane

   1. CAMS (cell adhesion molecules)

      1. Transmembrane proteins 

Intercellular connections:

SPECIFIC INTERCELLULAR JUNCTIONS 

Connections at specific areas or spots

Tight junctions 

Adhesion belt 

Gap junctions

SPECIFIC INTERCELLULAR JUNCTIONS 

TIGHT JUNCTIONS

• proteins bind or “stitch” two plasma membranes together

• Blocks water and solutes between cells

SPECIFIC INTERCELLULAR JUNCTIONS 

ADHESION BELT

• CAMS hold cells together

• Attached to terminal web

  1. Network of microfilaments

• Prevents distortion and leakage 

SPECIFIC INTERCELLULAR JUNCTIONS 

GAP JUNCTIONS

• Held together by channel proteins called connexons 

• Allow rapid communication between cells

  1. Allows ions to pass

• Found in some epithelial tissue, heart muscle, some smoothe muscle, some neural tissue 

SPECIFIC INTERCELLULAR JUNCTIONS 

 desmosomes

• Dense areas if CAMS and intercellular cement

• Like a rivet

• Distribute bending twisting forces

SPECIFIC INTERCELLULAR JUNCTIONS 

hemidesmosome

• Found on deepest epithelial cells

• Attach cells to basement membrane

  1. Separates epithelia from underlying tissues

  2. Made of fibers

• have similar function to desmosomes

Basement membrane

1. Separates epithelia from underlying tissues

2. Made of fibers

Ways to classify epithelial tissue:

squamos vs cuboidal vs columnar 

• Squamous epithelia 

  • Thin and flat

• Cubodial epithelia 

  • Cube shaped

• Columnar epithelia

  • tall , slendder columns

Ways to classify epithelial tissue:

simple vs stratified  

• Simple epithelium 

  • Single layer of cells

• Stratified epithelium

  • Several layers of cells 

Simple squamous epithelium function

• Absorption and diffusion

• Reduces friction

• controls vessel permeability 

Stratified squamous epithelium function

Protect against mechanical stress and attacks

provides physical protection against abrasion pathogens and chemical attack 

Simple cuboidal epithelium function

limited protection, secretion and absorption

Stratified cuboidal epithelia function

rare

protection 

Transitional epithelium function

• Protein

• Allows change in size and appearance

• Stretches and recoils

• Returns to previous shape w/o damage

• In urinary system (e.g. bladder)

• Function: permits expansion and recoil after stretching

Simple columnar epithelium

• Absoption and secretion

• Protection from chemical stresses 

Pseudostratified columnar epithelium

• All cells have contact w basement membrane 

• Protection, secretion (cilia for movement of mucus)

• Stratified columnar epithelium function

• Rare

• May only have one columnar layer

• Function: protection

Endocrine vs exocrine glands

• ENDOCRINE GLANDS 

  • Release secretions into interstitial fluid

  • No ducts

• Exocrine glands

  • Release secretions onto epithelial surfaces

  • Through ducts

Mecocrine secretion vs Apocrine secretion vs Holocrine secretion

• Mecocrine secretion

  • Produces in gogli apparatus

  • Released by vesicles (exocytosis)

  • Example: sweat glands

• Apocrine secretion

  • Produced in golgi apparatus

  • Released by shedding cytoplasm

  • Example: mammary glands

• Holocrine secretion

  • Released by cells bursting

  • Kill gland cells 

  • Gland cells replaced by stem cells

  • Example: sebaceous (oil) glands

Serous glands

•  Watery secretions: Mixture of water and proteins

• Includes fluid in body, cavity blood serum

Mucous glands

• Secrete mucins

• Proteins that form gels

Mixed exocrine 

• Both serous and mucous

• Example: saliva

mucous (goblet) cells are the only 

unicellular glands

all other glands are multicellular 

3 components of connective tissues

1. Specialized cells

2. Solid extracellular protein fibers

3. Ground substance

• Fluid or gel like substance

Cells of connective tissue proper:

• Fibroblasts

• Very common, always present connective tissue proper

• Produces matrix

Cells of connective tissue proper:

• Fibrocytes

Maintain the fibers of matrix

Cells of connective tissue proper:

adipocytes

• Fat cells

  • The single, large fat droplet

  • Expand to store fat

  • Shrink as fats are released

Cells of connective tissue proper:

Mast cells (warning cells)

• Near blood vessels

• Stimulte inflammation after injury or infection

  • Release histamine (inflammation) and heparin (anticoagulant)

Cells of connective tissue proper:

Stem cells (mesenchymal cells)

• Respond to injury or infection

• Differentiate into fibroblasts, macrophages, etc.

Cells of connective tissue proper:

Macrophages

• Large, amoeba-like cells of the immune system

  • Eat pathogens and damages cells

  • Free moving or fixed

Cells of connective tissue proper:

White blood cells

• Mobile immune cells

  • Both phagocytic and antibody producing

3 connective tissue fibers

collagen fibers

• Long, straight, unbranched

• Strong and flexible 

• Resist force in one direction

3 connective tissue fibers

elastic fibers

• Contain elastin 

• Branched and wavy

• Return to original length after stretching

3 connective tissue fibers

reticular fibers

• Structure: Network of interwoven fibers (stroma)

• Strong and flexible 

• Resist force in many directions 

• Stabilizes cells and structures

Ground substance

Fills spaces between cells and fibers

Ground substance in connective proper

clear, colorless and syrupy

Ground substance in fluid connective tissues

water like

• Ground substance in supporting connective tissue

gel like

Connective tissue proper:

Loose connective tissue

• Fibers in a loose framework

• The “packing materials” of the body

  • Fill spaces

  • Cushion and stabilize cells

  • Support epithelia

3 TYPES OF LOOSE CONNECTIVE TISSUE

areolar

adipose

reticular 

Loose connective tissue: 

AREOLAR (all over the body) (good supporting tissue)

• Allows for movement and cushioning 

• Least specialized

  • Open framework

  • Viscous (thick ground substance)

  • All three fibers

Loose connective tissue: 

ADIPOSE

• Contain mant adipocytes (fat cells)

  • Store energy 

  • Absorbs shocks

  • Slows heat loss (insulation)

  • Function: provides padding and cushions shocks; insulates (reduces heat loss), stores energy

Loose connective tissue: 

RETICULAR

• Provides support for cells in organs

• Complex, three- dimensional network of reticular fibers

• Found in: liver, spleen, lymph nodes, bone marrow

Dense regular connective tissue

• Tightly packed, parallel collagen and some elastic fibers

• Stabilizes bone and muscle; allow muscle contractions

  • Tendons: attach muscles to bones

  • Ligaments: connect bone to bone and stablize organs 

dense irregular connective tissue 

• Interwoven networks of collagen fibers

  • Layered in skin

  • Around cartliages and bones

  • Forms capsules around some organ

  • support and strength in any direction

Fluid connective tissues:

Blood and lymph:

• Watery matrix of dissolved proteins

• Carry specific cell types (formed elements)

Fluid connective tissues:

BLOOD

• Watery matrix called plasma

• Formed elements

  • Red blood cells (erthrocytes) 

    • Transport oxyfen

• White blood cells (leukocytes)

  • Defend against infections

• Platelets

  • Cell fragments

  • Clot broken vessels

Fluid connective tissues:

LYMPH 

• Collects extracellular fluid

  • Monitored by immune system

  • Mixed nutrients, wastes

  • Returns to veins

• Cardiovasucular system (blood)

• Arteries: heart to body

• Capillaries: network between arteries and veins

• Veins: body to heart

• Lymphatic (lypmphoid) system (lymph)

lymphatic vessels

Supportive connective tissue

• Support soft tissues and body weight

Supportive connective tissues:

CARTILAGE AND CARTILAGE COMPONENTS

• Gel type ground substance

• Shock absorption and protection

COMPONENTS:

• Cartilage matrix

  • Gel containing embedded figures

• Chronrocytes (cartilage cells)

  • Embedded in cartilage matric 

  • Make and maintain matrix

Supportive connective tissues:

BONE

• Calcified (made rigid by calcium salts, minerals)

  • Weight support

Cartilage structure

• No blood vessels in cartilage

• Perichondrium

  • Membrane that covers cartilage

  • Outer fiber layer for strength

  • Inner cellular layer for growth and maintenance

Hyaline cartilage, structure and fuction

1. Stiff, flexible support

2. Reduces friction between bones

3. Function: provides stiff but somewhat flexible support; reduces friction between bony surfaces

elastic cartilage, structure and function

supportive but bends easily

Fibrocartilage (fibrous cartilage), structure and function

1. Limits movement

2. Prevents bone to bone contact

3. Pads knee joints 

4. Function: resists compression; between bone to bone contact; limits movement

Bone tissue components: bone ore osseous tissue and bone cells or osteocytes

• Bone or osseous tissue

  • strong , flexible matrix

    • Very little ground substance

    • Flexible collagen fibers

    • Strong calcium deposits

• Bone cells or osteocytes

  • Within matrix 

Structure and function of membranes:

Membranes:

• Line of cover portions of body

• Provides a physical barrier 

• Consist of epithelium, supported by connective tissue

4 types of membranes:

Mucous membranes (mucosae)

Serous membranes

Cutaneous membrane

Synovial membranes

Mucous membranes (mucosae), structure and function

1. Line passageways with external openings

   1. Digestive, respiratory, urinary and reproductive tracts

2. Epithelial surfaces must be moist

   1. Reduce friction

   2. Absoption and excretion

serous membranes, structure and function

1. Line internal body cavities

2. Covers organs

3. Delicate

4. Allows serous fluid to diffuse from underlying tissues

   1. Reduces friction

cutaneous membrane

1. Skin surface of body

2. Thick, relatively waterproof, and dry

synovial membranes

1. Joint cavities 

2. Protect ends of bones

3. Produce synovial fluid (lubricant)

4. Lacks true epithelium

5. Line joint cavities and produce the fluid within the joint

Muscle tissue

• Specialized for contraction

• Body, organ, tissue movement

Skeletal muscle tissue

Body movement

cardiac muscle tissue

only in the heart

smooth muscle tissue

1. In walls of hollow, contracting organs

   1. Blood vessels, urinary bladder respiratory, digestive and reproductive tracts

Classification of muscle cells:

BANDING 

• Straited: with a banded appearance

  • Patterns of microfilaments (actin) and thick filaments (myosin)

Classification of muscle cells:

NUCLEI

•  Can have single nucleus 

• Can be multinucleate

Classification of muscle cells:

CONTROL

• Voluntary: consciously

• Involuntary: automatically

Skeletal muscle cells:

• Long and thin (muscle fibers)

  • Multinucleate

  • Straited, voluntary

  • Functions: moves or stabilizes the position of the skeleton; guards entances and exirs to different tracts amd generates heat; protects the internal organs

Cardiac muscle cells

• Most w one nucleus

• Straited, involuntary

• Branching networks of connected cells

Smooth muscle cells:

• Small and tapered

• Nonstriated

• Involuntary

• Single nucleus

• Can divide and regenerate (can regenerate quite easily)

Neural tissue (function):

Neural tissue (or nervous tissue)

• Tissue that conducts electrical impulses

• Most neural tissue concentrated in CNS

  • Brain and spinal cord

Two types of neural cells:

neurons and neuroligia

NEURONS function

Preforms electrical communication

neurologia function

1. Physically support neurons

2. Maintain chemical environment

3. Supply nutrients to neurons

4. Defend against infection

Inflammation:

• inflammation= inflammatory response

  • First response to injury

Signs and symptoms of the inflammatory reposne include:

can be triggered by cell:

• Swelling 

• Redness

• Heat 

• Pain

• Can be triggered by cell damage from:

  • Trauma (physically or chemical injury)

  • Infection (harmful pathogens)

Process of inflammation:

• As cells are damaged:

  • Lysosomes release enzymes

    • Destroy the injured cell

    • Attack surrounding tissues, why?, so infection doesnt spread

  • Cellular debris (pus) accumulates in wound

    • Abcess

      • Pus trapped in an enclosed area

The process of inflammation:

damaged cells:

• Damaged and dying cells release high concentrations of molecules into the surrounding of molecules into the surrounding intersitiaul fluid, which include:

  • Toxins and wast

  • Pathogens

  • Immune markers or cells

  • Cell chemicals

The process of inflammation:

mast cells

• Mast cells detect signals, job to detect higher concentration of these materials

• Signals of the injury/infection stimulate mast cells to release:

  • Histamine and heparin

    • Vasodilation: widening of bloof vessels

    • Increases blood vessel permeability

The process of inflammation:

Dilation of blood vessels (vasodilation)

• Increases blood cirulation in the area 

• Causes warmth and redness

• Brings more nutrients and oxygen to the area

• Brings leukocytes

• Removes wastes

The process of inflammation:

Plasma, phagocytic, and platlets

• Plasma diffuses into area, which causes pain and swelling

• Phagocytic white blood cell clean up the area

• Platelets form clots

  • Temporary

  • Produce protein fibers (fibrin)

The process of regeneration:

• After injury or infection is cleaned up

• Fibrocytes move into area

  • Become fibroblasts

  • Lay down collagen fibers

  • Bind the are together (scar tissue)

The process of regeneration:

• New cells

  • Migrate into area

  • Produced by stem cells

• Epithelia and connective tissues

  • Regenerate well

• Cardiac cells and neurons

  • Do not regenerate (or regenerate poorly)