A and P Mod. #2 Tissues

Module #2 Histology

Histology – the study of tissues

Four tissue types:Epithelial ConnectiveMuscleNerve

Epithelial

Tissuehttp://lima.osu.edu/biology/images/anatomy/Stratified%20squamous%20epithelium%20400X.jpg

General Features of Epithelial Tissue

•Cells are closely packed with little extracellular material (between cells)

•Are in continuous sheets

•Single or multiple layered


•Epithelia is avascular meaning “without blood vessels”.

•Nutrients and wastes are exchanged by diffusion with the adjacent connective tissue.


•have a free surface which is exposed to a body cavity, lining of an internal organ, or the exterior of the body, and

• a basal surface which is attached to the basement membrane.

basal surface


•Subject to wear, tear and injury, so has a high capacity for renewal (high mitotic rate).

•Functions include protection, filtration, lubrication, secretion, digestion, absorption, transportation, excretion, sensory reception, and reproduction.


•Epithelial tissue sits on a basement membrane located between it and the tissue underneath.

http://www.ouhsc.edu/histology/Glass%20slides/13_04.jpg

Epithelial tissue

Connective tissue

There are two kinds epithelial tissue based on function:

(1) lining or covering epithelium – covers the skin and outside of some internal organs, forms the inner lining of body cavities, blood vessels, and internal organs.

Epithelial Tissue con’t

There are two kinds epithelial tissue (function):

(2) glandular epithelium - consists of cells that secrete substances. (ex. Thyroid/sweat/oil glands)

Epithelial Tissue con’t

Epithelial tissue can be divided into categories based on……

>the shape of the cells and

> the number of layers of cells.

SHAPES of epithelium:

1. Squamous -flat cells-thin which allows substances to pass through (diffuse) them. -have limited cell structures due to size

2. Cuboidal cube shapedImportant in secretion and absorptionHave more cell structures than squamousUses active transport to secrete and absorb substances

3. Columnar cells are tall and cylindrical Have the most cell structures Most complex Most secretion ability

4. Transitional •cells can readily change shape from squamous to columnar•change shape due to stretching, of body parts. (ex. Found in bladder)

http://photos1.blogger.com/blogger/7703/2162/1600/stratified%20epi.jpg

Arrangement of Layers

1. Simple epithelium a single layer of cellsfound in areas where diffusion, osmosis, filtration, secretion and absorption occur.Can be squamous, columnar, or cuboidal Ex. lungs


2. Stratified epithelium contains two or more layers of cells protects underlying tissues found where there is wear and tearEx. Skin Named by the free surface.

http://photos1.blogger.com/blogger/7703/2162/1600/stratified%20epi.jpg


3. Pseudostratified epithelium contains a single layer of a mixture of cell typeshas a stratified appearance but is a single layerAll cells touch basementmembrane

Glandular EpitheliumColumnar epithelium that contains special cells capable of synthesizing and secreting certain substances such as enzymes, hormones, milk, mucus, sweat, wax and saliva

Glandular Epithelium

Goblet cells :

Special columnar cells that their function is to secret mucin which mixes with water to form mucous - intestines

Goblet cell

Glandular Epithelium

There are two types of glands:

1. Exocrine glands • secrete their products to

the target by ducts• most glands in the body

are exocrine glands (sweat/salivary)

• All have secretory portion and a duct

Exocrine Gland

Exocrine glands come in many arrangements/types:

Glandular EpitheliumThere are two types of glands:

1. Exocrine glands

Types of exocrine glands based on how they secrete:

a. Merocrine glands – by exocytosis (without losing cellular material) into the duct.

Example sweat glands.

Merocrine gland directly secretes into duct.

http://www.med.umich.edu/histology/fieldTrip/sweatGland.jpg


1. Exocrine glands

Types of exocrine glands based on how they secrete: a. Merocrine glands

b. Apocrine glands - a portion of the plasma membrane containing the secretion and some cytoplasm buds off the cell and enters the duct.

Ex. Mammary glands

Apocrine Gland

There are two types of glands:

1. Exocrine glands

Types of exocrine glands based on how they secrete: a. Merocrine glands

b. Apocrine glands

c.holocrine gland - the entire cell containing its secretion

disintegrates in the duct.

Ex. Oil glands


1. Exocrine glands

2. Endocrine gland no ducts secrete hormones by exocytosis intointerstitial fluids that surround cellsand blood stream picks them up.Ex. Thyroid gland

Endocrine Glands

Type Function LocationSimple Squamous Diffusion Blood vessels, lungsSimple Cuboidal Diffusion and secretion Kidneys

Simple Columnar Mucous producing Stomach and intestines

Stratified Squamous Protection, secreting Skin, lining mouth

Stratified Cuboidal Protection, secreting Protect Salivary glands - rare

Stratified Columnar Protection, secreting Pharynx, larynx, uterus - rare

Stratified Transitional Stretches, changes shape Urinary bladder

Epithelial Tissue – Functions and locationsHandout

Why does skin flake off? Cells at top of skin are so far from nutrients that they are dead.

Keratin – protein that fills dead epidermal cells at top layer

Keratinized membrane – top layer of skin cells that are dead and filled with keratin.

Where quiz stops

CONNECTIVE TISSUE

FUNCTION: insulate, support and bind (infrastructure)

CONNECTIVE TISSUE continued

CHARACTERISTICS:

Greater space between cells (extracellular space) compared to epithelial tissue

cells secrete extracellular material or MATRIX which fills space between cells


CHARACTERISTICS:

Matrix is the material between the cell which contains ground substance (non-collagenous part of matrix) and collagen protein fibers.


CHARACTERISTICS:

Connective Tissue is classified according to the type of extracellular matrix it produces

CONNECTIVE TISSUE

TYPES:1. connective tissue proper2. cartilage3. bone4. blood

http://en.wikipedia.org/wiki/Image:Illu_connective_tissues_1.jpg

http://www.google.com/imgres?imgurl=http://www.tigerpath.com/images/unit_08/051_Blood.jpg&imgrefurl=http://www.tigerpath.com/unit_08.htm&h=480&w=640&sz=72&tbnid=ACKM8GH8lxgJ::&tbnh=103&tbnw=137&prev=/images?q=picture+blood+tissue&hl=en&usg=__zCrdk2vOQ_LErtghOU1dE5WqlA8=&sa=X&oi=image_result&resnum=1&ct=image&cd=1

TYPE 1: Connective Tissue Proper

Guess how many kinds of connective tissue proper

there are?

4


Four types of Connective Tissue Proper:

A. Loose connective tissueExtracellular matrix is not strong

Is used for light binding and flexibility

Also called areolar connective tissue


Four types of Connective Tissue Proper:

A. Loose connective tissue

Found between the skin and the muscles holding the skin to musclesHas fibroblasts which make tissue’s ground substance, protein fibers, collagen fibersMature fibroblast are called

fibrocytes

Loose Connective Tissue Proper

fibroblast

Four types of Connective Tissue Proper:A. Loose connective tissue

B.Dense irregular connective tissue

Part of the skin

Collagen fibers more densely packed than loose connective tissue

B. dense irregular connective tissue continued

Denser packing give tissue more strength

Irregular because fibers run every which way

Dense irregular connective tissue proper

Four types of Connective Tissue Proper:A. Loose connective tissueB. Dense irregular connective tissue

C. Dense regular connective tissue properCollagen fibers run in one

direction giving more strength called tensile strength

Found in tendons which hold muscle to bones and ligaments that hold bone to bone

c. Dense regular connective tissue proper

Tendons and ligaments take a long time to heal when injured because of dense amount of extracellular material (fibers, etc.) that they must manufacture.

Dense regular connective tissue proper

Four types of Connective Tissue Proper:A. Loose connective tissueB. Dense irregular connective tissueC. Dense regular connective tissue proper

D. Adipose tissue

Fatty tissue

it has fat cells in it as well as connective tissue cells

D. Adipose tissue

Function is to store energy, insulate, and to hold organs in place

Example – kidneys are protected and held in place by adipose tissue

CONNECTIVE TISSUE

TYPES:1. connective tissue proper

2. Cartilage Supporting connective

tissue with tensile strength and supporting fibers of collagen in the ground substance

CONNECTIVE TISSUE

TYPES:1. connective tissue proper2. Cartilage

• Firmer than connective tissue proper

• Has no blood supply• Thin matrix• Found in nose, ear,

larynx• Often replaced by bone

CONNECTIVE TISSUE


Chondroblasts – immature cartilage cells that produce the matrix fibers.

CONNECTIVE TISSUE


Chondrocytes – mature chondroblast that become trapped in matrix and live in hollow spaces called lacuna in the cartilage tissue.

Lacuna (histology), a small space containing an osteocyte in bone or chondrocyte in cartilage

http://en.wikipedia.org/wiki/Lacuna_(histology)

CONNECTIVE TISSUE


3 types of cartilage:

A. Hyaline cartilage occurs at end of bones,

external ear, fetal skeleton, nose, ribs and vertebrae

Weakest and most common

CONNECTIVE TISSUE

TYPES:1. connective tissue proper2. Cartilage3 types of cartilage:

B. Elastic cartilage found in epiglottis and

external ear contains elastic fibers great flexibility and is able to

withstand repeated bending

CONNECTIVE TISSUE

TYPES:1. connective tissue proper2. Cartilage3 types of cartilage:

C. Fibrous cartilage Strongest Dense collagen fibers with limited

ground substance Found in disk between vertebrae and

skull Where bears great amount of weight Has fibrous appearance

CONNECTIVE TISSUE - Cartilage

CONNECTIVE TISSUE


3. Bone: Hardest connective tissue

Consist of cells, collagen fibers, and mineralized (calcium and phosphate) ground substance

CONNECTIVE TISSUE

TYPES:1. connective tissue proper2. Cartilage3. Bone:

Ground substance becomes hard or calcified through a process known as calcification

CONNECTIVE TISSUE

TYPES:1. connective tissue proper2. Cartilage3. Bone:

Has a rich blood supply

Properly known as osseous tissue

CONNECTIVE TISSUE

TYPES:1. connective tissue proper2. Cartilage3. Bone

Types of bone cells:

A. Osteoblasts- make components of bone

CONNECTIVE TISSUE



B. Osteocytes – mature osteoblasts found in lacuna

CONNECTIVE TISSUE



C. Osteoclasts – reasorb bone and remodel it

CONNECTIVE TISSUE


4. Blood transports

Also known as vascular tissue

Two types of cells – red and white

CONNECTIVE TISSUE

TYPES:1. connective tissue proper2. Cartilage3. Bone4. Blood

Ground substance = proteins in blood

Has fluid part – blood plasma

Has clotting fibers

New Topic: Membranes

Membrane = layers oftissue

There are three categories of membranes:



1. Mucous found in linings of organ systems that open to the outside



1. Mucous

Ex. Respiratory system, reproductive system, digestive system

Traps foreign material



2. Serous line the body cavities that do not open directly to the outside

they cover the organs located in those cavities



2. Serous

are covered by a thin layer of serous fluid that lubricates and is secreted by the epithelium



2. Serous

Serous fluid lubricates the membrane and reduces friction and abrasion when organs move against each other or the cavity wall.



3. Synovial membranes

connective tissue membranes that line the cavities of the freely movable joints such as the shoulder, elbow, and knee.



3. Synovial membranes

secrete synovial fluid into the joint cavity, and this lubricates cartilage on the ends of the bones so that they can move freely and without friction.

New Topic: tissue repair

Remember: Tissues are made up of cells.

Two types of cells that make up tissue based on function:

1. Stromal cells – provide structure and support to tissue; usually connective tissue


Remember: Tissues are made up of cells.

Two types of cells that make up tissue based on function:

1. Stromal cells – provide structure and support to tissue

2.Parenchymal cells – cells that actually perform the function of the tissue

Organ Parenchyma

kidney nephron

lungs alveoli, respiratory bronchiole, alveolar duct and terminal bronchiole

spleen white pulp and red pulp

brain neuron

liver hepatocyte

http://en.wikipedia.org/wiki/Kidney

http://en.wikipedia.org/wiki/Nephron

http://en.wikipedia.org/wiki/Lung

http://en.wikipedia.org/wiki/Pulmonary_alveolus




http://en.wikipedia.org/wiki/Spleen

http://en.wikipedia.org/wiki/White_pulp

http://en.wikipedia.org/wiki/Red_pulp

http://en.wikipedia.org/wiki/Brain

http://en.wikipedia.org/wiki/Neuron

http://en.wikipedia.org/wiki/Liver

http://en.wikipedia.org/wiki/Hepatocyte


Categories of cells based on ability to reproduce or regenerate:1. Labile cells cells that multiply constantly

throughout life Most of cells in body ex. Parenchymal epithelial

cells replace themselves quickly


Categories of cells based on ability to reproduce or regenerate:

2. Stable cells only multiply when receive

external stimulus to do so ex. Bone parenchymal cells

when a bone is broken can reproduce and repair the broken bone


Categories of cells based on ability to reproduce or regenerate:

3. Permanent cells do not have the ability to

multiply

Nervous system parenchymal cells (neurons) are permanent; can’t be replaced.


So, if cells are parenchymal permanent and die they will be replaced by labile stromal cells..

This is why brain damage or heart damage is said to be irreversible.

A and P Mod. #2 Tissues

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