Chapter 4: Tissue - The living Fabric Flashcards
Tissues
Groups of cells with similar structures and related functions.
Histology
study of tissues
Four basic tissue types
epithelial, connective, muscle, nervous tissue
Epithelial Tissue
epithelium
- is a sheet of cells that covers the body surface or cavities
* skin**
two main forms of epithelial tissue
- Covering and lining epithelia
- Granular epithelia
Covering and lining epithelia
on external and internal surfaces
Skin
Glandular Epithelia
secretory tissue in glands
oil and sweat
5 special characteristics of epithelial tissues
- Polarity, Specialized contacts, Supported by connective tissues, Avascular but innervated, Regeneration
Polarity of the epithelial tissue
cells have polarity(top and bottom)
- two types: apical and basal surface
Apical surface
upper side (top)
-exposed to surface or cavity
Basal surface
lower side (bottom)
- faces inward toward body
Specialized Contacts (epithelial tissue)
epithelial tissues need to fit closely together
Supported by connective tissues (epithelial tissue)
all epithelial sheets are supported by connective tissue
melanoma
is the most aggressive form of skin cancer because cancerous epithelial cells cannot be contained and they penetrate the boundary and invade underlying tissues, resulting in the spread of cancer
-starts with moles
Avascular but innervated (epithelial tissues)
no blood vessels are found in epithelial tissue = no blood supply
*epithelia is supplied by nerve fibers
Regeneration (epithelial tissues)
epithelial cells have high regenerative capacities
(regens very fast and really well)
classification of epithelia
classified by two names
- the first name indicates # of cell layers
- second name indicates shape of cells
epithelia two types of layers (first name for classification)
Simple epithelia
Stratified epithelia
simple epithelia
one layer thick
stratified epithelia
two or more layers thick
(involved in protection, ex: skin)
epithelia types of cell shapes (second name for classification)
Squamous
Cuboidal
Columnar
Squamous
flattened and scale-like
flat
Cuboidal
box-like, cube
Columnar
tall, column-like
Simple epithelia
involved in absorption, secretion, or filtration processes
Simple squamous epithelium
- 1 layer of flat cells
- rapid diffusion
- located in lungs and blood vessels
Simple cuboidal epithelium
- one layer of box cells
- involved in ***secretion
- located in glands and ducts (sweat glands, etc.)
Simple columnar epithelium
parallel rows of tall cells
- involved in absorption
- found in intestines (small)
Pseudostratified columnar epithelium
- looks multilayered (but isn’t - pseudo means false)
- cells with different heights (cells are ciliated)
- involved in movement of mucus via ciliary sweeping action
- located mostly in lower respiratory tract
Stratified epithelial tissues
- multilayered
- new cells generate from below (basal cells divide and move towards the surface)
Stratified squamous epithelium
- multiplayers of squashed cells
- located in areas of wear and tear (epidermis of skin)
- keratinized cells, non-keratinized cells
keratinized cells
found in skin
non-keratinized cells
moist linings/tissue
Transitional epithelium
- found in the bladder, ureters, and urethra
- cells change shape and is stretched (like when bladder is full it stretches and changes the shape of the cells)
Glandular epithelia
glands
classified by: Endocrine, Exocrine
Gland (glandular epithelia)
- one or more cells that makes/secretes an aqueous fluid called a secretion
Endocrine
internally secreting (ex: hormones)
-secretes directly into blood
- ductless
Exocrine
externally secreting (ex: sweat)
-has ducts
-there’s more of this in the body (sweat glands.. etc.)
Types of exocrine glands
- merocrine (aka eccrine)
- holocrine
- apocrine
Merocrine
aka eccrine
- type of exocrine glands
- sweat glands
Holocrine
- oil glands
- sebaceous glands (same thing as oil glands, sebum means oil)
Apocrine
- armpit and and groin glands
Connective Tissue
most abundant and widely distributed of primary tissues
Four main classes of Connective tissue
- connective tissue proper
- cartilage
- bone
- blood
Common characteristics of connective tissues
- common embryonic origin
- varying degrees of vascularity (blood supply)
- extracellular matrix
all connective tissues have three main elements
- ground substance
- fibers
- cells
extracellular matrix
ground substance and fibers
Ground Substance
- aka interstitial fluid
- fluid in between ce
ground substance components
- interstitial fluid
- proteoglycans (sugar protein molecule)
three types of Fibers
- collagen
- elastic fibers
-reticular
collagen
-strongest and most abundant type
- tough and provides high tensile strength
*** where you get strength from **
Elastic fibers
- gives you recoil
cells
- Blast and cyte cells
Blast cells
- makes/ builds something
- ex: fibroblasts, chondroblasts, osteoblasts
fibroblasts
- making fibers (connective tissue proper)
chondroblasts
makes cartilage
osteoblasts
bone building cells
Cyte cells
- mature adult cells
far cells
***in adipose tissue
- store nutrients
White blood cells
- tissue response to injury
connective tissue proper
consists of all connective tissues except bone cartilage, and blood
two subclasses of CT proper
- CT proper: loose connective tissues
- CT proper: dense connective tissues
CT proper: 3 loose connective tissues
- areolar
- adipose
- reticular
CT proper: 3 dense connective tissue
- dense regular
- dense irregular
- elastic
areolar
- loose connective tissue
- in the dermis of skin (2nd layer under epidermis), under the epithelium/epidermis
- lots of collagen
- acts as water reservoir
Adipose
- loose connective tissue
- fats
- White fat: very vascular; acts as insulation, energy storage, and shock absorption
- brown fat: keeps babies warm (so mostly in babies)
(every organ in the body is wrapped in fat)
* in subcutaneous (hypodermis) layer*
white fat
adipocytes
- richly vascularized
- shock absorption, insulation, and energy storage
Reticular connective tissue
* lymphatic system*
Dense regular connective tissue
- very high tensile strength
- poorly vascularized
- has a lot of thick collagen fibers
- ex: tendons and ligaments
tendons connects
muscle to bone
ligaments connects
bone to bone
Dense irregular connective tissue
- thick density irregular collagen (no pattern)
- found in the dermis (reticular layer), fibrous joint capsules, fibrous coverings of some organs
Dense Elastic connective tissue
- some are very elastic
-
also found in walls of many large arteries
(densely packed and elastic)
Cartilage
- chondro (?)
- 80% water, with packed collagen fibers, and sugar proteins
- avascular
Avascular
receives nutrients from the membrane surrounding it
types of cartilage
- hyaline cartilage
- elastic cartilage
-fibrocartilage
Hyaline cartilage
most abundant, tips of long bones
Elastic cartilage
- external ears
Fibrocartilage
- nice and strong
- located in the knee
Avascular cartilage
when we age it loses the ability to divide thus injuries heal slowly
- common in people with sports injuries
- meniscus of the knee, labrum of shoulder/hop, disc of spine
Bone
- has more collagen compared to cartilage
- has inorganic calcium salts (hydroxy)
- richly vascularized
Blood
- IS A TISSUE
- atypical connective tissue bc it is a fluid
- red blood cells are the most common cell type
- contains white blood cells and platelets
- function: transport
Muscle tissue
- highly vascularized (heals well)
- responsible for movement
three types of muscle tissues
- skeletal muscle
- cardiac muscle
- smooth muscle (involuntary)
Skeletal muscle tissue
- attached and causes movement of bones
- voluntary muscle
- muscle fibers
cardiac muscle tissue
- found only in walls of the heart
- involuntary muscle
- cells have many branches
smooth muscle tissue
- in hollow organs (GI, blood vessels, bronchi)
- involuntary muscle
nervous tissue
- the main component of the nervous system (brain, spinal cord, nerves)
two specialized cells of the nervous tissue
- neurons
- glial cells
Three types of lining membranes
- cutaneous membranes (skin)
- mucous membranes
- serous membranes
cutaneous membrane
skin
mucous membranes
- mucosae
- moist lining bathe by secretions
- digestive, respiratory, urogenital tracts
tissue repair (inflammation)
immunovascular response to injury
(healing takes place bc of inflammation)
Regeneration
same kind of tissue replaces destroyed tissue, so original function is restored
Fibrosis
connective tissue replaces destroyed tissue, and original function lost
Steps in tissue repair
- inflammation sets the stage
- organization restores blood supply
- Regeneration and fibrosis effect permanent repairs
Inflammation sets stahe
step 1 in tissue repair
- inflammatory chemicals
- dilation of blood vessels
Organization restores blood supply
step 2 in tissue repair
- fibroblasts produce collagen fibers to bridge gap until regeneration
Regeneration and fibrosis effect permanent repair
- the scab detaches
- fibrous tissue matures
- epithelium thickens and begins to resemble adjacent tissue
tissues with great regenerative capabilties
- epithelial tissues
- bone
- areolar connective tissue
- dense irregular connective tissue
- blood-forming tissue
Tissues with moderate regenerative capabilities
- smooth muscle, and dense regular connective tissue
Tissues with poor and no regenerative capabilities
almost doesn’t heal
- cardiac muscle, nervous tissue of the brain, and spinal cord
