Anatomy Exam 2 Unit 4

Tissues differentiate during..

Development to carry out specific functions

For ex: When sperm fertilizes the egg it becomes a zygote. This cell can be specialized in the muscle, skin, and liver

Genes turn off

4 major tissues in the body

Epithelial

Connective

Muscular

Nervous

Epithelial Tissue

Lines body cavities that open to the exterior; specialized for \n absorption, secretion and excretion

Connective Tissue

Specialized to support and cushion the body; the binding tissue, also fights infection

Muscular Tissue

Specialized for contraction

Nervous Tissue

Specialized tissue that generates electrical impulses

Epithelial Tissue features

consists mainly of cells bound together by junctions; little \n extracellular material

Apical Surface

faces interior or exterior space

Basal surface

attached to CT layer by the basement membrane

Avascular

no blood vessels; obtains substances by diffusion

High rate of cell division in…

ET; cells near basement membrane constantly \n undergoing mitotic division

Epithelial Tissue functions

1. Physical Protection- Barrier, Abrasions, Dehydration

2. Control Permeability- Selective Absorption (Digestive tract)

3. Provide sensations about environment- Hot, Cold Pressure

4. Produces specialized secretions by forming glands

2 type of glands in ET

Endocrine and Exocrine

Endocrine gland

Glands are ductless \n - Hormones are simply secreted into circulation

Endocrine gland example

thyroid and pituitary

Exocrine gland

Gland secretions are discharged into ducts \n - Empty onto skin or other epithelial surface

Exocrine gland

Lacrimal glands, perspiration onto skin, milk in \n mammary glands

Epithelial Tissue 3 different shapes

squamous, cuboidal, columnar

Squamous

fried eggs, snake scales look

Cuboidal

cube-like

Columnar

Tall columns

Epithelial 3 cell arrangements

Simple, stratified pseudostratified

Simple

single layer

delicate, fragile

Simple ET location

internal protected areas

Simple ET function

diffusion, absorption, filtration

Stratified

several layers

Stratified ET location

external

Stratified ET function

protection

Pseudostratified

actually simple, but appears stratified

all cells directly contact the basement membrane

Simple squamous ET

Most delicate and allows for diffusion/absorption to take place

Simple squamous ET location

lines outside of intestine and lining of blood vessel

Simple squamous ET also forms..

serous membrane \n o Lines ventral cavities and organs \n o Pleura (lungs), pericardium (heart) and peritoneum \n (abdominopelvic cavity)

Stratified squamous ET

Protection against physical/chemical attacks

Stratified squamous ET location

found in high stress areas

eg: skin (outermost layer) & vagina

Simple Cuboidal ET

adapted for secretion/absorption

Simple Cuboidal ET location

Rare; found in sweat glands and mammary glands

Simple columnar ET Non-ciliated

Secretion/absorption

Simple columnar ET Non-ciliated location

lining of small intestine

Simple columnar ET ciliated

protection/movement

Simple columnar ET ciliated location

respiratory tract and fallopian tubes

Ciliated pseudostratified columnar ET

Single layer, but looks like more \n - Nuclei are multilayered \n - All cells are still in contact with the basement membrane \n - Its really just ciliated simple columnar in disguise!

Ciliated pseudostratified columnar ET location

trachea

Connective Tissue is the…

most widely distributed tissue in the body

Connective tissue contains specialized cells in and secretes…

1. Extracellular Protein fibers

2. Ground substance

Ground Substance (CT)

(a clear viscous fluid)

* The extracellular protein fibers and ground substance \n form the matrix.

Matrix (CT)

a nonliving mixture that exists within the intracellular spaces.

* It can be hard (bone), rigid (cartilage), fluid (blood)

CT is made up mostly of

matrix

ET is made up mostly of

cells

CT is found in underlying..

structures (not on surface structures like ET was).

CT is highly…

vascularized

ET had no blood supply

CT functions as a structural framework to…

interconnect and protect, a transport medium, an energy reserve and a defense system against invading microorganisms.

CT is classified according to 3 things

1. types of fibers

2. types of cells

3. types of matrix

In CT, what is not vascularized

cartilage

Types of cells that may be found within connective tissue like…

Fibroblasts

Leukocytes

Adipocytes

Melanocytes

Mesenchymal

Mast Cell

\
MMALMF

__M__y __M__others __A__ss __L__ooks __M__f __F__at

Fibroblasts

produce fibers that are found within CT and help to produce parts of the matrix

Leukocytes

(WBCs) are commonly found in blood, but can also migrate into CTs temporarily

Leukocytes examples

Macrophages

Macrophages

phagocytize foreign materials and also signal to \n activate the immune system when stimulated.

Adipocytes

(fat cells)- store lipids

Melanocytes

synthesize and store a brown pigment called melanin. Melanin colors the epithelium (epidermis) and CT (dermis) of the skin.

Mesenchymal

stem cells that respond to injury or infection by dividing and \n then differentiating into different CT cells

Mast cells

“WBC” contain histamine and heparin which stimulate inflammation

CT fibers are formed by..

fibroblast

The types of fibers in CT

Collagen fibers, Reticular Fibers, Elastic Fibers

Collagen fibers

“Waves”

Most numerous of the 3 fiber types \n o Long, straight and unbranched \n o Composed of the protein, which is VERY STRONG. \n o Appear white when present in large numbers

Reticular fibers

“Network”

Thinner than collagen fibers \n o Tend to form branched networks

Elastic Fibers

“Branched and wavy when not stretched”

Have the ability to stretch and then return to original length \n o Composed of the protein elastin

Elastic fibers are found in:

the air sacs of lungs, dermis of the skin, blood vessels and in between vertebrae

Reticular fibers are found in and provide..

a strong supporting net that helps to stabilize the organs, BV, nerves and other structures.

Collagen Fiber are found in:

Tendons and ligaments

Loose connective tissue

packing material; cushion and stabilize; fill spaces between \n organs; surround and supports other tissues

Areolar connective tissue is the most…

widely distributed of all the connective tissues.

Areolar connective tissue

Very loosely organized with an open framework (this allows it to distort without damage)

\n o has very few cells (mostly fibroblasts and macrophages) \n that are not organized in any particular manner.

Areolar connective tissue function:

Forms a layer that separates the skin from underlying \n structures. This serves to absorb multidirectional shock and permits distortion without damage.

Areolar connective tissue location:

between epithelial tissue and muscle tissue. Acts similar to \n glue, holding these two structures together.

Adipose Tissue

Contains mostly adipocytes (fat cells), which have only a small area of cytoplasm and a large fat droplet

Areolar Tissue

different fibers are scattered throughout the matrix

Adipose Tissue

very little matrix. The cells are packed closely together and look something like chicken wire.

Adipose Tissue Function

serves as padding, shock absorber (TG) and filling, as well as an \n insulator and energy preserve

Adipose Tissue location

can be found under the skin and around certain organs

These adipocytes can be stimulated by the nervous system to breakdown their lipid contents..

which leads to an increase in body temperature.

eg: Brown fat, found in infants, is different because it is highly vascularized and also contains numerous mitochondria

Reticular connective tissue

Made primarily of these fibers \n o Will see many dark cells with dark r. fibers scattered throughout

Reticular connective tissue function

provides a framework to supports cells within

Reticular connective tissue location

the spleen, liver, lymph nodes and bone marrow

Dense connective tissues

are dense with protein fibers

Dense regular connective tissue

Very few cells (a few fibroblasts which produce the many collagen fibers)

Composed of bundles of collagen which are arranged in orderly, parallel rows (looks wavy)

Dense regular connective tissue function

secures bones during movement

Dense regular connective tissue location

Tendons, Ligaments, Aponeurosis

Dense Regular CT

Tendons:

unite skeletal muscle cells; attaches skeletal muscle to bones

Dense Regular CT

Ligaments:

attach bone to bone

Dense Regular CT

Aponeurosis:

a flat, sheet-like structure that attaches muscle to bone or bone to bone

Dense irregular connective tissue

Collagen fibers are not arranged in any particular pattern. The fibers are scattered in various directions.

Dense irregular connective tissue function

the scattered unordered fashion that the fibers are arranged \n in actually adds to their strength when they are being pulled in different directions.

Dense irregular connective tissue location

around in joints and also forms a layer around cartilages \n (perichondrium) and around bone (periosteum)

Elastic Tissue

A dense, regular connective tissue that is dominated by elastic fibers \n o Looks like lasagna when viewed from the side

Elastic Tissue function

the large amounts of elastic tissue allow it to stretch and then return to its normal size and shape

Elastic Tissue location

found in the lungs and in some arteries

Vascular Tissue contains…

Blood Lymph and Cartilage

Blood

Consists of a liquid matrix called plasma (fluid part of blood) \n o Within the plasma are the suspended elements:

erthrocytes, leukocytes, platelets

Erythrocytes “RBC”

transports oxygen and carbon dioxide