Chapter 5 (Unit 1) Flashcards
Name the four primary classes into which all adult tissues are classified.
Epithelial Tissue,
Connective Tissue,
Nervous Tissue,
and Muscular Tissue
Epithelial Tissue is broken down into two major sections:
- Epithelia
- Glands
Epithelia
Sheet of closely adhering cells (and small amount of extracellular matrix) lining the surface of the body
Epithelia is ___________ (vascular/avascular), but __________.
avascular; innervated
Apical Surface
Exposed portion of epithelia - may have cilia there or microvilli for more surface area or some modification that tells us what it does
Basal Surface
Bottom/anchoring portion of epithelia touching the basement membrane
- Basal surface keeps epithelium tissue anchored
[unrelated: under basement membrane, there is connective tissue]
Lateral Surface
Side portions of epithelia - have junctions here (gap junctions, tight junctions, etc)
What does it mean when we say all epithelium display polarity?
Two different surfaces, apical and basal, with different properties/functions
How is epithelial tissue regenerative?
Because epithelial cells are always getting damaged since they are on the outside of the body, so epithelial cells are constantly regenerating
- the mitosis occurring provides the nutrients energy for?
Glands: Function
Secrete substances for use elsewhere in the body or for elimination as waste
Why are glands/ secretion needed in epithelia?
needed because epithelia is avascular
Secretion vs. Excretion
Secretion = when product is useful to body
Excretion = when waste product
Functions of Epithelial Tissue (and how those functions are performed)
- PROTECTION: barrier against environmental or chemical factors or against microorganisms 🦠
- SECRETION: sweat, mucus (nose, stomach), bile (to break down), enzymes.
- ABSORPTION
- FILTRATION
- EXCRETION: in places like the kidneys (urea)
- SENSATION: innervated; nerves allow us to feel sensations (feel when you swallow, touch, etc)
What functions of epithelial tissue regulate permeability?
(permeability = ability to get across that barrier we made)
- Absorption
- Filtration
- Excretion
What are the two ways in which epithelia are classified?
- # of cell layers
- cell shape
Epithelia: Types of Cell Layers
- Simple: one layer
- Pseudostratified Columnar: “pseudo” = fake; one layer pretending to be multiple layers
- Stratified: multiple layers
Epithelia: Cell shapes
- Squamous: flat, thin; looks like a flat egg in a pan
- Cuboidal: kind of square/round, roundish; as tall as it is wide
- Columnar: taller than it is wide
Simple Squamous Epithelium:
structure, location, function
Structure:
Simple = Single layer,
Squamous = thin cells
Location: Lungs, Kidney, Heart, Blood vessels, Stomach, Intestines, Pleura, Pericardium, Peritoneum, Mesentery
- Air sacs (alveloi) of LUNGS
- Glomular capsules of KIDNEY tubules
- Inner lining (endothelium) of HEART and BLOOD VESSELS
- Serous membranes of STOMACH, INTESTINES, and some other viscera
- Surface mesothelium of PLEURA, PERICARDIUM, PERITONEUM, and MESENTERIES.
Function: Rapid diffusion/transport and secretion
- RAPID DIFFUSION or TRANSPORT of substances through membrane
- SECRETION of lubrication serous fluid
Simple Cuboidal Epithelium:
structure, location, function
Structure:
Simple = Single layer,
Cuboidal = cube-like cells (square or round); as tall as it is wide
- Brush border of MICROVILLI in some kidney tubules
- CILIATED in bronchioles of lung
Location: Liver, Thyroid, Mammary Glands, Salivary Glands, Kidney, Bronchioles (Lungs)
Function:
- ABSORPTION & SECRETION
- PRODUCTION of productive MUCOUS coat
- MOVEMENT of respiratory MUCUS
Pseudostratified Columnar Epithelium:
structure, location, function
Structure:
- Pseudostratified = Single layer pretending to be multi
- Columnar = taller than it is wide
- Often with GOBLET CELLS
- Often CILIATED
Location:
- RESPIRATORY TRACT from nasal cavity to bronchi
- Portions of MALE URETHRA
Function: Secretes and Propels mucus
Stratified Squamous Epithelium–Keratinized:
structure, location, function
Structure:
- Stratified = Multi-Layer
- Squamous = thin cells
- KERATIN = TOUGH - prevents things from crossing that barrier
- Surface covered with a layer of compact dead cells w/o nuclei
Location:
- EPIDERMIS & PALMS AND SOLES are heavily keratinized
Function: RESISTS ABRASION & PENETRATION by pathogenic organisms (PROTECTION)
- and retards water loss through skin!
To distinguish between Squamous, Cuboidal, or Columnar, look at:
cells on APICAL surface
Stratified Squamous Epithelium–Nonkeratinized:
structure, location, function
Structure:
- Stratified = Multi-Layer
- Squamous = thin cells
- SAME AS KERATINIZED BUT w/o surface layer of dead cells
Location: Openings of body essentially
- Tongue, Oral mucosa, Esophagus, Anal canal, Vagina
Function: RESISTS ABRASION & PENETRATION by pathogenic organisms
Stratified Cuboidal Epithelium:
structure, location, function
Structure:
- Stratified = Multi-Layer
- Cuboidal = cube-like cells (square or round); as tall as it is wide
Location:
- SWEAT GLAND ducts
- Egg-producing vesicles (follicles) of OVARIES
- SPERM-producing ducts (seminiferous tubules) of TESTIS
Function:
- Contributes to SWEAT SECRETION
- SECRETES ovarian HORMONES
- PRODUCES SPERM
Urothelium (or Transitional Epithelium):
structure, location, function
Structure:
- Somewhat resembles STRATIFIED SQUAMOUS EPITHELIUM, but surface cells are ROUNDED not flattened and often BULGE at surface
- typically 5-6 CELL thick when RELAXED and 2-3 CELL thick when STRETCHED (cells may be flatter and thinner when urothelium stretched)
- Some cells have 2 nuclei
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
Functions of Simple vs. Stratified Epithelia:
Simple (One layer) - Secretion & Absorption
Stratified (Multi layer) - Protection
Types of Cellular Junctions
- Tight Junctions
- Desmosomes
- Gap Junctions
- Hemidesmosomes
Tight Junctions
Will interlock and make our barrier
- Stop things from moving between cells - will force things to go into or through cells
Desmosomes
Will allow us to have a little bit of movement between cells but keep the cells together in the face of mechanical stress [analogy = velcro]
- also found in skin a little bit deeper –> allow us to rub our skin without tearing it
Gap Junctions
Structure: transmembrane proteins come together to form connexion
- pore within the structure allows for substances to move from one cell to another (for example: ions)
Hemidesmosomes
found on basal surface
- attaching cells to basement membrane
Exocrine
Makes secretion and releases wither to tracts to outside of body
- Not only on external surfaces, can also be on internal surfaces
Exocrine
Secretion stays within tissue of the body
- DUCT: all exocrine glands have this
Some examples of multicellular glands or/and location:
Sweat glands: Simple Coiled Tubular Gland
Mammary gland: Compound Acinar Gland
Pancreas: Compound Tubuloacinar
Modes of Secretion
Eccrine (Merocrine) Glands = will use exocytosis to get secretion out & doesn’t change or damage cell at all
Apocrine Secretion = pinching off on apical side (ex: mammary glands) & barely any damage to cell at all
Holocrine Secretion = secretes through exploding (ex: pores) & once exploded, cell is dead (clearly damage to cell!!)
Collagenous Fibers
thick, rope-like structures which are flexible
- give strength to our tissues (resists forces) in ONE direction
[STAIN PINK]
Reticular Fibers
branching, thinner than collagenous fibers BUT creates network/grid for cells to sit on and to wait to do their function
[STAIN BLACK]
Elastic Fibers
allows you to stretch and force is gone, can go back to original size w/o damage (only fiber that can go back w/o damage!!!)
[STAIN PINK?]
Areolar Tissue:
structure, location, function
Connective tissue -> Fibrous connective tissue -> Loose connective tissue -> Areolar tissue
Structure:
- LOOSE arrangement of COLLAGENOUS &
ELASTIC FIBERS
- SCATTERED cells of various types
- ABUNDANT ground
substance
- NUMEROUS blood vessels
Location:
- Underlying nearly all EPITHELIA
- Surrounding
BLOOD VESSELS, NERVES, ESOPHAGUS, and TRACHEA
- Fascia between
MUSCLES
- Mesenteries
- Visceral layers of pericardium and pleura
Functions:
- LOOSELY BINDS epithelia to deeper tissues
- ALLOWS PASSAGE
of nerves and blood vessels through other tissues
- PROVIDES an ARENA
for immune defense
- Blood vessels provide NUTRIENTS & WASTE
REMOVAL for overlying epithelia
Reticular Tissue:
structure, location, function
Connective tissue -> Fibrous connective tissue -> Loose connective tissue -> Reticular tissue
Structure:
- LOOSE network of RETICULAR FIBERS & CELLS
infiltrated with numerous LEUKOCYTES, especially LYMPHOCYTES
Location: Lymph nodes, Spleen, Thymus, Bone marrow
Function: FORMS SUPPORTIVE stroma (framework) for lymphoid organs
Dense Irregular Connective Tissue:
structure, location, function
Connective tissue -> Fibrous connective tissue -> Dense connective tissue -> Dense Irregular connective tissue
Structure:
- Densely PACKED collagen fibers running in RANDOM directions
- Scanty open space (ground substance)
- Few visible cells
- Scarcity of blood vessels
Location:
- Deeper portion of dermis of SKIN
- Capsules around viscera such as LIVER, KIDNEY, SPLEEN
- Fibrous sheaths around
CARTILAGES & BONES
Function:
- WITHSTANDS STRESSES applied in unpredictable directions
- Imparts DURABILITY to tissues
White Adipose Tissue (WAT):
structure, function
Connective tissue -> Adipose tissue -> WAT
Structure:
- EMPTY-LOOKING cells with THIN margins
- Nucleus pressed against cell
membrane
- Very little matrix
Function: Energy storage, insulation, cushioning
Hyaline Cartilage:
structure, location, function
Connective tissue -> Supportive connective tissue -> Cartilage -> Hyaline Cartilage
Structure:
- Clear, glass matrix stained light blue or pink in tissue sections
- Dispersed collagen fibers, not usually visible
- Chondrocytes enclosed in lacunae, often in small clusters of 3-4 cells (cell nests
- USUALLY covered by perichondrium
Location:
- A thin articular cartilage lacking perichondrium over the end of BONES
- Supportive rings and plates around TRACHEA & BRONCHI
- A BOX-like enclosure around the LARYNX
- Much of the FETAL SKELETON
- A costal cartilage attaches the end of a RIB to the BREASTBONE
Function:
- EASES joint movements
- HOLDS AIRWAY OPEN during respiration
- MOVES VOCAL CORDS during speech
- A PRECURSOR of bone in the fetal skeleton and the GROWTH ZONES of long bones of children
Elastic Cartilage:
structure, location, function
Supportive connective tissue -> Cartilage -> Elastic Cartilage
Structure:
- ELASTIC FIBERS form web-like mesh amid lacunae
- ALWAYS covered by perichondrium
Location: External EAR & EPIGLOTTIS
Function: Provides FLEXIBLE elastic SUPPORT
Fibrocartilage:
structure, location, function
Supportive connective tissue -> Cartilage -> Fibrocartilage
Structure:
- PARALLEL collagen fibers similar to those of tendon
- Rows of chondrocytes in lacunae b/w collage fibers
- NEVER has perichondrium
Location:
- PUBIC symphysis (anterior joint b/e two halves of pelvic girdle)
- INTERVERTEBRAL DISCS, which separate bones of vertebral column
- Menisci, or pads of shock-absorbing cartilage, in KNEE joint
- At points where TENDONS insert on BONES near articular HYALINE CARTILAGE
Function:
- RESISTS COMPRESSION & ABSORBS SHOCK in some joints
- Often a TRANSITIONAL TISSUE b/w dense connective tissue and hyaline cartilage (ex: at some tendon-bone junctions)
