Week 5: Tissues Flashcards
Histology
Study of the structure of animal tissue on a microscopic level. Also looks at how tissues are arranged into organs.
Tissue
a group of similar cells that perform the same specific function; Example: muscle, cardiac, or nerves
Tissue Types
- Epithelial: covers body surfaces and organs, lines body cavities
- Connective: bind and supports body parts
- Muscular: contracts producing movement
- Nervous Tissue: responds to stimuli and transmits nerve impulses
Epithelial Tissue Structure
- Tightly packed cells
- Readily divides (mitosis) producing new cells to replace old or damaged cells
- Lack Blood Vessels
- Exists on the skin and on the surface of organs, blood vessels, and body cavities
Epithelial Tissue General Location, Structure, Function (Externally/ Internally)
- Externally: protects body from drying out, injury, and bacterial invasion
- Internally: protects, sweeps up impurities, secretes mucus, absorbs
Covers surfaces and lines cavities:
- has free surface
- other surface attached to the underlying tissue by the basement membrane
Simple vs Stratified Epithelial Tissue
- Simple Epithelial Tissue: composed of a single layer of cells
- Stratified Epithelial Tissue- composed of 2 or more layers of cell
Types of Epithelial Tissue
- Squamous - simple and stratified
- Cuboidal Epithelial - simple and stratified
- Columnar Epithelial- simple and stratified (rare, found in pharanyx, laryanx, and anal canal)
- Psuedostratified Epithelial
- Transitional Epithelial
Squamous Epithelium
- simple: single layer of squamous
2. stratified: multiple layer of squamous
Simple Squamous Epithelium
- Single layer of flattened cells
- Function: secretion, absorbtion, and filtration
- Location: lines the lungs, blood vessels, and heart
Stratified Squamous Epithelium
- Many layers of flattened cells
- Function: protection
- Location: outer layer of skin, lining various orfices of the body
Cuboidal Epithelium
- Simple: single layer of cube shaped cells attached to a basement membrane
- Stratified: two or more layers of cube shaped cells
Cuboidal Epithelium Location & Function
Glands: secretion
Kidney Tubules: secretion and absorbtion
Simple Columnar Epithelium
Composed of cells that are longer than wider
-Nucleus found in the lower half of the cell
Simple Columnar Epithelium Location & Function
Digestive Organ: absorbtion
Uterine Tubes: propel egg to uterus
Pseudostratified Epithelium: Location,Appearance, & Function
Cells appear to be layered due to irregulary placed nuceli but each cell touches the basement membrane
- May contain cilia- aids in the movement of particles
- Function: protection, secretion, movement of mucus, and sex cells
- Location: respiratory tract, reproductive tracts
Transitional Epithelium: Location & Function
Tissue that changes in response to tension
Found in organs that need to stretch
Location: urinary bladder, ureters, urethra
Connective Tissue Structure,Function, & Location
Structure:
- widely separated by ECM (can be solid, semi-solid, or liquid)
- Matrix of connective tissue determines its properties
Location:
- Tendons & ligaments
- Cartilage & Bone
- Blood
Function:
- Binds Structures together
- Provides Support & Protection
- Fills Spaces
- Produces Blood cells
- Stores Fat: for energy, insulation, organ protection
Matrix Fibers
- White Fibers (collagenous fiber): contain collagen which gives the fibers flexibility and strength. Examples; Tendons, Ligaments, and Dermis of Skin are mainly made up of this.
- Yellow Fibers (elastic fiber): contain elastin -more elastic than collagen but not as strong. Very spring like (will recoil after stretched. Found in skins, lungs, and arteries helping them spring back after stretched.
- Reticular Fibers: thin, highly branched/ spongelike collagenous fibers that provide support. Found in organs such as the spleen & lymph nodes; found in basement membrane in underlying epithelial
Fibrous Connective Tissue Types
Most diverse Type
- Loose (areolar) connective tissue
- Adipose - Dense Connective Tissue
- Regular
- Irregular - Reticular Connective Tissue
Loose (Areolar) Connective Tissue: Location, Attributes, Function
Location:
- Exists in tissue sections throughout the body
- Lies between other tissues or between organs binding them
- Surrounds blood vessles and nerves, esophogus & trachea; fascia btw. muscles; mesentries; visceral layers of pericardium and pleura
Attribute:
- Cells made of fibroblasts- large, star-shaped cells
- Contains many white fibers (strong and flexible) and yellow fibers (very elastic)
Function:
- loosely binds epithelial to deeper tissue
- allows passage of nerves and blood vessels through other tissues
- provides an arena for immune defense
- blood vessels provide nutrients and waste for removal for overlying epithelial
Adipose Tissue: Location, Appearance, and Function
- Type of loose connective tissue
- Function: stores fat- provides insulation
- Location: found beneath skin, around kidney & heart, breast
Dense Connective Tissue: Types, Location, Atrributes, and Function
- Regular
- consists of parallel bundles of collagenous fibers–> structure allows for predictable stress ie.musculoskeletal stresses pulling tendons and ligaments in predictable directions.
- found in tendons and ligaments
- binds organs together - Irregular
- bundles run in different directions–> structure allows for response to unpredictable stress
- found in inner portion of skin, protective capsule around the kidneys, testes, and spleen; as well as around bones, nerves, and most cartliages.
Reticular Connective Tissue: Location, Attributes, and Function
Location:
- Also called lymphatic Tissue
- Found in lymph nodes, spleen, thymus, and red bone marrow
Atrributes:
- Has Reticular Fibers
- Spongelike in appearance
Function:
- Store and produce white blood cells
- Part of immune system
Cartliage: Structure, Location, & Function
Structure:
- Relatively stiff connective tissue with flexible rubbery matrix
- Produced by chondroblasts
- The cell (chondrocytes) lies in small chambers called lacunae
- Lacks direct blood supply, as a result, it heals slowly)
Location: ears, larynx (voice box), trachea (windpipe)
Function:elastic support, flexibility; eases joint movement, holds airway during respiration, moves vocal cords during speech; resists compression and avoids shock, etc
Cartliage Types
- Hyaline
- Elastic Cartliage
- Fibrocartliage
Hyaline Cartliage
Structure:
- Most Common
- Matrix contains fine collagenous fibers (glassy, white, opaque)
- Found in nose, ends of the long bones and ribs, rings in the trachea
Location: ends of moveable joints; trachea/ bronchi; larynx; costal cartliage
Function: eases joint movements, holds airway open during respiration, moves vocal cords during speech
Elastic Cartliage
Structure:
-Contains elastic and collagenous fibers
Location:
-Found in the outer ear
Function:
-provides flexible, elastic support
Fibrocartliage
Structure:
-Matrix contains strong collagenous fibers
Location:
-Found in the pads between the vertabrae and knee joints
-Function: absorbs shocks and reduces friction between joints
Bones
- most rigid of the connective tissues
- minerals and protein fibers give bone rigidity, elasticity and strength
Bone Types
- Compact Bone
2. Spongy Bone
Compact Bone: Location, Structure, and Function
Location:
Found in the outer portion of long bones
Structure:
-Consists of many cylindrical-shaped units called osteon (cell)
Function:
-Provides structure/ strength of bone
Osteon
Cylindrical shaped units found within compact bone
Spongy Bone
- Found on ends of long Bone
- Contains bony bars and plates called trabeculae separated by irregular spaces
- Blood cells are made within the red marrow found in the spongy bone
Trabeculae
Bony bars and plates found within the spongy bone
Blood: Structure, Cell Types, and Function
- Connective Tissue composed of cells suspend in liquid matrix called plasma
- Red Blood Cells (erthryocytes)- carries oxygen
- White Blood Cells (leukocytes)- fights infection
- Platelets- fragment of giant cells found in bone marrow
Red Blood Cells
erthryocytes- carries oxygen
White Blood Cells
leukocytes- fights infection
Platelets
Structure:
fragment of giant cells found/ made in bone marrow
Function:
Aid in blood clotting to stop/prevent bleeding
How types of tissues differ
They differ in the types and function of their cells, the characteristics of the matrix (extracellular material) that surround the cells, and the relative amount of space occupied by the cells and the matrix.
Example: in muscle and epithelium, the cells are so close together that the matrix is scarcely visible but in connective tissues, the matrix occupies much more space than the cells do.
Nervous Tissue: Function & Location
Structure/ Function:
- Tissue containing excitable cells specialized for rapid transmission of coded information to other cells
- Cells: Neurons and Glial
Location:
- Brain
- Spinal Cord
- Nerves
Muscular Tissue: Function/ Structure & Location
Structure:
-Tissue composed of elongated, excitable muscle cells specialized for contraction.
Location:
- Skeletal Muscles
- Heart (cardiac)
- Walls of viscera (smooth muscle)
Function:
-body movement, digestion, breathing, speech, blood circulation, etc.
Matrix Composition/ Material:
- Ground Substance
- Tissue Fluid
- ECF
- Interstitial Fluid
Mesenchyme
A gelatinous tissue composed of fine, wipsy collagen that forms into cardiac muscle, bone, and blood, among other tissue.
Formed from mesoderm (layer between ectoderm and endoderm) during early human development.
Histological Sections
Microscope method to study tissues- way to imagine 3D images based off 2D preparations
Histological Stains are used to study and enhance details different parts of the anatomy. These stains bind to different components of each part.
Epithelial Tissue Function: Part 2
- Protection- prevents bacterial invasion and injury. Outer layer ie. epidermis is a barrier to infection while inner layer ie. stomach protects deeper tisssue from stomach acid and enzymes.
- Secretion-produces mucus, sweat, enzymes, hormones ie. glands are composed of a ton of epithelial.
- Excretion-void waste from the tissues, such as CO2 from the pulmonary epithelial and bile from the liver.
- Absorbtion- absorbs chemicals from the adjacent medium, ie: nutrients in the small intestine.
- Filtration-All substances leaving the blood are selectively filtered through the epithelium that lines the blood vessels; all urinary wastes is filtered through epithelial of the kidneys.
- Sensation- provided with nerve endings that sense stimulation ranging from touch on skin to irritation of the stomach.
Avascular
Without blood vessles; Example: epithelial are avascular bc there is no room for them between the cells. Epithelial usually lie on vessel rich layer of connective tissue which furnish them with nutrients and waste removal.
Basement Membrane
Exists between epithelial and connective tissue. Controls the exchange of materials between the two.
Basal Surface
Faces the basement membrane
Apical Surface
Faces the free surface/ area of the lumen
Lateral Surface
Between the Basal and Apical
Exfoliation
Loss/ migration/ death of daughter cells from squamous epithelium. Become flatter (more scaly), die, and flake off.
Keratinoctyes
- Also called cornified cells
- Dead compressed cells that exist on the apical surface of squamous stratified epithelial.
Urothelium
Specialized type of epithelial cell that somewhat resembles a stratified squaemous but is more round in shape.
Location: Urinary Tract - part of kidney, ureter, bladder, part of urethra
Function:Stretches to allow filling of urinary tract; protects underlying tissues from osmotic damage by urine.
Connective Tissue Functions
- Binding of organs: tendons bind muscle to bone; ligaments bind bone to bone;fat holds the kidneys and eyes in place; fibrous tissue binds the skin to the underlying muscle.
- Support: Bones support the body, cartliage supports the ears, nose, larynx, and trachea; fibrous tissues form the framework of organs such as the spleen.
- Physical Protection: the cranium, ribs, and sternum protect delicate organs such as the brain, lungs, and heart; fatty cushions protect the kidneys and eyes.
- Immune Protection: connective tissue cells attach foreign invaders, and connective tissue fiber forms a battlefield under the skin and mucus membrane where immune cells can be quickly removed against disease agents.
- Movement: Bones provide the lever system for movement; cartliage are involved in movement in the vocal cord; and cartliage on bone surfaces ease joint movement
- Storage: fat is the body’s major energy reserve; bone is a reservoir for calcium and phosphorus that can be drawn upon when needed.
- Heat Production:metabolism of brown fat generates heat in infants and children.
- Transport: blood transports gases, nutrients, wastes, hormones, and blood cells.
Connective Tissue Types (Broad Categories)
- Fibrous Tissue
- Areolar Tissue ; ex: Adipose
- Supportive Connective Tissue (Bone & Cartliage)
- Fluid Connective Tissue (Blood)
Fibrous Connective Tissue: Components
- Fibroblasts
- Macrophages
- Leukocytes (or WBC)
- Plasma Cells
- Mast Cells
- Adipocytes
Adipocytes
Fat Cells; when they cluster together they form adipose
Ground Susbtance
featurless empty space between the cells but typically protects delicate cells from mechanical injury
Areolar & Epithelium
-Most epithelium rests on areolar tissue, whose blood vessels provide the epithelium with nutrition, waste removal, and a ready supply of infection fighting leukocytes in times of need.
Adipose Tissue:
Location:
-Subcutenaous fat beneath skin; breast; heart surface; mesenteries; surrounding organs such as kidneys and eyes
Structure:
-Dominated by adipocytes
Function:
- energy storage
- thermal insulation: heat production by brown fat
- protective cushion for some organs
- filling spaces
- shaping body
How to tell between dense irregular tissue and arerolor tissue ?
Areolar typically has a larger amount of clear space AND dense irregular has thicker bundles of collagen and relatively little clear space.
Yellow vs White Fat
White Fat:
- more abundant
- provides thermal insulation, anchors and cushions such organs such as the eyeballs and kidney, and contributes to body contours such as female breast and hips
Brown Fat:
- mainly found in fetuses, infants, and children
- located in shoulders, upper back, and around kidneys
- gets color from blood vessles
- Heat Generating but energy doesnt come from ATP–> energy is given off as heat
- Hibernating Animals produce a ton of brown fat
Adipose vs Areolar
Areolar is loose connective tissue where as Areolar is a specific type of loose connective tissue.
Inervated
Supplied with nerves
Avascular
Not serviced by blood vessels
Connective tissue derive from..
Mesenchume (a paticular type of embryonic tissue)
Connective tissues are made up from
- Ground Substance
- Fibers
- Cells
ECM is made up of
- Ground Substance
2. Fibers
Ground Substance is made up of
Interstiual Fluid
Types of connective tissue cells
- Immature (not fully formed as specialized cell)
a. fibroblast-connective tissue proper
b. chondroblast- cartliage
c. osteoblast- bones
d. hematopoietic stem cells- blood - Mature (fully formed)
a. fibrocyte
b. chondrocyte
c. osteocyte
d. many more (adipocytes, kertinocytes)
Cartliage vs Dense Connective Tissue
Cartilage can withstand tension AND compression
Bone is made up of
- Collagen
2. Inorganic Calcium Salts- make it solid/ hard
Bone vs Cartliage
Bone contains blood vessles