Chapter 4 Tissue

The cutaneous membrane

"dry" membrane exposed to air, consists of a keratinized, stratified squamous epithelium called, the epidermis, and an underlying layer of connective tissue called, the dermis.

Which muscle cell type has visible striations but is not under voluntary control?

-Cardiac -cardiac cells, like skeletal cells, have visible striations but are not under voluntary control.

Which type of gland produces hormones?

-Endocrine glands, which are ductless glands, secrete hormones into the interstitial fluid surrounding them. The hormones then diffuse toward and pass through a nearby capillary wall to enter the blood. Circulating throughout the body in the blood stream is how hormones eventually reach their target cells

Pseudostratified epithelium consists of multiple cell layers, True or False?

-FALSE- -While pseudostratified epithelium has the illusion of being a multi-layered tissue, it is in fact made up of only one cell layer. The irregular heights of the cells in pseudostratified epithelia give the tissue a layered appearance. In reality, all of the cells in this tissue rest on the basement membrane (i.e., their basal surfaces are in contact with the basement membrane).

Why are adipose, blood, and bone all considered to be connective tissues?

-They have a common origin, mesenchyme, an embryonic tissue -- Also common to all connective tissues is the presence of cells and an extracellular matrix that consists of fibers bathed in ground substance

Which type of epithelium lines the interior of the urinary bladder?

-Transitional epithelium -Transitional epithelium forms the lining of hollow urinary organs, which stretch as they fill with urine. The ability of transitional cells to change their shape (undergo "transitions") allows a greater volume of urine to flow through the tube-like ureters and allows more urine to be stored in the urinary bladder.

Smooth muscle ________.

-is under involuntary control

In connective tissue, the role of collagen fibers is to ________?

-provide tensile strength -extremely tough and provide high tensile strength (that is, the ability to resist being pulled apart) to the matrix. Stress tests show that collagen fibers are stronger than steel fibers of the same size!

D) Connective Tissue Cells-

Each type of connective tissue has a dominant cell type that exists both in immature (-blast) and mature (-cyte) form The immature cells secrete the ground substance and fibers

Glandular epithelial tissue: Endocrine Glands

Endocrine Glands- Internally secreting, known as ductless glands. -produce hormones that enter the blood -Most endocrine glands are multi-cellular organs

Which tissue type consists of a sheet of cells that covers a body surface or lines a body cavity?

Epithelial tissue---- is a sheet of cells that covers a body surface or lines a body cavity (epithe = laid on, covering). In addition to coverings and linings, epithelial cells can also form glands, called glandular epithelium.

glandular epithelial tissue: Exocrine Glands

Exocrine glands secrete their products onto the body surfaces or into body cavities. -Includes mucous, sweat, oil, and salivary glands

3. Glandular Epithelia:

Gland consists of one or more cells that secrete a product -Glands are classified based on where they secrete their product, and by the number of cells

________ is the tissue that regulates and controls body functions.

Nervous tissue.

connective tissues are?

Primarily consist of extracellular matrix. Largely nonliving extracellular matrix, which separates, often widely, the living cells of the tissue.

Holocrine glands secrete their products by?

Rupturing. Sebaceous (oil) glands are the only example of holocrine glands in the body.

3. Types of Connective Tissue-major differences in CT reflect cell type and types and amounts of fibers

called mesenchyme. This arises from during the early weeks All mature CT arises from common embryonic tissue of embryonic development, and then differentiates into all other connective tissue cells.

Stratified epithelial tissue contains?

contain two or more layers of cells, regenerate from below, basal cell divides and push apically. More durable than simple epithelium, protection is major function

Mucous membranes line the exits and entrances to the body. There are four main "tracts" lined with mucosae

digestive, respiratory, reproductive, and urinary. Each is exposed, at one or both ends, to the outside environment.

Endocrine glands are?

ductless; they secrete hormones into the extracellular fluid of our internal environment. endo= inside

glandular epithelial tissue

endocrine glands and exocrine glands

glandular epithelium

fashions the glands of the body

Microvilli

are small finger-like projections that greatly increase the surface area of epithelial cells (thus epithelial tissues), an important attribute of tissues that have a role in absorption and secretion.

transitional epithelia are found in areas that?

stretch, in particular the ureters and urinary bladder.

Stratified squamous epithelia are found in areas?

subjected to wear and tear

All other primary tissues are composed mainly of cells

besides connective tissues

Roles of connective tissue include?

binding and support, protection, insulation, and transportation of substances, via blood, within the body.

Four primary tissue types

Epithelial- Covers Connective- Supports Muscle- Produces movement Nervous- Controls

Tissues

Groups of cells that are similar in structure and preform a common or related function

To preform specific body functions, the tissues are organized into?

Organs

Smooth and cardiac muscle are?

under involuntary control

Skeletal muscle is?

under voluntary control.

Mucous cells are?

unicellular exocrine glands that secrete mucin, a protein that combines with water to form mucus

Epithelial Membranes

А. Epithelial membranes- covering and lining membranes 1. epithelium + underlying connective tissue 2. cutaneous membrane а. skin b. only dry membrane 3. mucous membrane a. lines all body cavities that open to the outside world b. most secrete mucus for moisture and protection 4. serous membrane a.) line body cavities that do not open to the outside world b.) the always occur in pairs 1- visceral layer 2- parietal layer 3- serous fluid c.) peritoneum, pleurae and pericardium

2. Cutaneous membrane

а. skin b. only dry membrane

The proximal tubule of the nephron (kidney tubule) in the kidney is composed of which type of epithelium?

-simple cuboidal epithelium -simple cuboidal cells line the kidney tubules (nephrons) so that secretion and absorption can take place

The wall of the alveolus (air sac) in the lung is composed of which type of epithelium?

-simple squamous epithelium - this single layer of squamous cells is ideal for the diffusion of gases in the lungs.

Which of the three muscle cell types has multiple nuclei?

-skeletal muscle cells are elongated and many can be quite long; therefore, they have multiple nuclei.

injured cartilage might heal more quickly if a treatment were discovered that would __________?

-stimulate blood vessels to develop within cartilage -Cartilage is normally avascular, so nutrients required for healing must diffuse from distant blood vessels, which delays the healing process

The epithelium of the esophagus is composed of which type of epithelial tissue?

-stratified squamous epithelium - this epithelium protects underlying tissues from the wear and tear of constant swallowing in the esophagus.

D.Nervous Tissue

1) Neurons-transmit the nervous impulse 2)Neuroglia - supporting cells а) CNS b) PNS-

C.Muscle Tissue-used for movement of materials

1) Skeletal Muscle-involved in body movements -30ox - attached to the skeleton - long cylinders with lots of nuclei voluntary - striated -elongated Cell -multhe le penphenl nudc 2) Cardiac Muscle-involved in heart movement to pump blood -400 -found in the heart wall - Ks and Hs with a nucleus in each cell - striated - intercalated discs -involuntary -Branching cdll 5ingle Central nudeus 3) Smooth Muscle -involved in moving substances throughout the body - found surrounding all hollow organs - long cells with a single nucleus and tapered ends - involuntary -lack of visible striations -spindle-Shaped cell

Characteristics of Epithelium

1. Polarity- All epithelium exhibit a: ---Apical surface- upper free surface exposed to the exterior --- Basal surface- a lower attached surface 2. Specialized Contacts- epithelial cells fit closely together to form continuous sheets. Tight junctions and desmosomes help bind lateral contacts. 3. Supported by connective tissue- All rest upon and are supported by connective tissue. Basal lamina and reticular lamina from the basement structure 4. Avascular, but innervated- Contains no blood vessels, but does have nerve fibers. 5. Regeneration- has high regenerative capacity, and reproduce rapidly

A.) Simple Epithelia- most concerned with absorption, secretion, and filtration

1. Simple Squamous Epithelium- single later of thin, flat cells -flattered laterally, sparse cytoplasm -close-fitting cells resemble tile floor -found where diffusion or rapid filtration is needed -endothelium and mesothelium are two other examples 2. Simple Cuboidal epithelium- a single layer of cube-shaped cells - spherical nucleus - function for secretion and absorption - found in the walls of many ducts of glands 3. Simple Columnar Epithelium- a single layer of tall cells - oval-shaped nuclei - function for absorption and secretion - often contain dense microvilli, mucus-producing cells, and cilia. 4. Pseudostratified Columnar Epithelium- cells vary in height, but all rest on the basement membrane, some reach apical surface. - cells nuclei vary in height, giving a stratified appearance. - often found with cilia and mucus-producing cells

Classification of Epithelial Tissue:

1. Simple vs Stratified- the number of layers of cells -Simple- a single layer of cells -Stratified- two or more layers of cells 2. Squamous, Cuboidal, and Columnar- the shape of the cells -Squamous- Flattened cells -Cuboidal- box-like cells -Columnar- tall column-shaped cells *the shape of the nucleus always conforms to shape of cell

B. Stratified Epithelia- contain two or more layers of cells, regenerate from below, basal cell divides and push apically. More durable than simple epithelium, protection is major function

1. Stratified Squamous Epithelium- Several layers of cells, with thin, flat, squamous cells on the apical surface. - Thick and well sited for protection - found in locations where we have lots of wear and tear - Keratinized vs. non-keratinized 2. Stratified Cuboidal Epithelium- two layers or cube-shaped cells - Quite rare in the body, found mostly in the ducts of some larger glands (sweat and mammary glands) 3. Stratified Column Epithelium- two layers of cells, apical late columnar, basal later cuoidal - limited distribution, pharynx, male urethra, some ducts 4. Transitional Epithelium- domelike apical cells that stretch - found lining the hollow urinary organs which stretch as they fills - Vary from 3- 6 cells thick based on degree of stretch

types of exocrine glands

1. Unicellular-Secrete via exocytosis a. Mucous cells and goblet cells that secrete mucin 2. Multicellular Exocrine glands- Structurally more complex, have both a duct and a secreting unit a. Structure classification- classified by duct structures i. Simple Glands- unbranched duct ii. Compound glands- beached duct b. Modes of Secretion- can secrete products in different ways i. Merocrine- secretes via exocytosis - no damage to cell, ex. sweat and saliva ii. Holocrine- cell ruptures to secrete product - cells needs to be replaced, ex. oil glands iii. Apocrine- The apex pinches off - controversial whether this exists in humans

B. Connective tissue membranes-

1. synovial membrane - loose areolar tissue and no epithelium а.) surround joints b.) synovial fluid

Epithelial tissue (or an epithelium) is?

A sheet of cells that covers a body surface or lines a body cavity

B.Connective Tissue. 1. Characteristics of Tissue-

A) Common Origin - ALL C.T. arises from mesenchyme (embryonic tissue) B) Degrees of Vascularity-varies in vascularity, from being avascular (cartilage), to poorly vascularized (dense connective), to richly Vascularized (adipose, osseous) C) Extracellular Matrix- not just made of cells, but has a large nonliving extracellular matrix which often separates the living cells. This allows it to bear weight, withstand tension, etc.

2. Structural Elements of Connective Tissue-the composition and arrangement of the following three elements vary, allowing for extreme diversity of CT's.

A) Ground Substance- unstructured material that fills the space b/t cells and contains the fibers. 1) Composed of interstitial fluid, cell adhesion proteins, and proteoglycans 2) extracellular matrix allows tissues to bear weight, withstand tension, endure physical trauma and abrasion because it is not living B) Connective tissue fibers- proteins that provide support a. Collagen fibers- are primarily collage, are extremely thick and strong, are the most abundant b. Elastic fibers- long thin fibers, contain elastin, that allows for stretch and recoil c. Reticular fibers- short, fine collagenous fibers into a delicate network -offer a combination of strength and stretch

Characteristics of connective tissue-

A.) Common Origin- all C.T. arises from mesenchyme (embryonic tissue) B.) Degrees of Vascularity- varies in vascularity, from being a vascular (cartilage), to poorly vascularized (dense connective), to richly Vascularized (adipose, osseous) C.) Extracellular matrix- not just made of cells, but has a large nonliving extracellular matrix which often separates the living cells. -This allows it to bear weight, withstand tension, etc.

Simple epithelial tissue is most concerned with what bodily functions?

Absorption, Secretion, and Filtration

What is not a role of connective tissue?

Absorption, the movement of substances into the body, is a role of epithelial tissue. Roles of connective tissue include: binding and support, protection, insulation, and transportation of substances, via blood, within the body.

A) Connective Tissue Proper-

All mature CT except bone, cartilage and blood

study of tissues; provides the structural basis for a study of organ physiology

Histology

Which of the following increases the surface area of certain epithelial tissues?

Microvilli are small finger-like projections that greatly increase the surface area of epithelial cells (thus epithelial tissues), an important attribute of tissues that have a role in absorption and secretion.

Which part of the neuron (a specialized nerve cell) receives signals from other cells and is also the main metabolic region of the neuron?

Soma -the soma or cell body receives inputs (signals) from other cells and sends the information to the axon. But unlike a dendrite, it also is the main metabolic and nutritional center of the cell

The arrangement of specific tissues, and the arrangement of these tissues, determines the organs?

Structure and function

All connective tissues arise from an embryonic tissue called mesenchyme. True or False?

TRUE -All connective tissues arise from an embryonic tissue called mesenchyme. Mesenchyme has a fluid ground substance containing fine sparse fibers and star-shaped mesenchymal cells. It arises during the early weeks of embryonic development and eventually differentiates (specializes) into all other connective tissue cells. However, some mesenchymal cells remain and provide a source of new cells in mature connective tissues

Connective Tissue Cells-each

a. Fibroblast- b. Chondroblast- c. Osteoblast- d. Connective tissue is also home to an assortment of other cell types: - Fat Cells - White Blood Cells - Mast Cells - Macrophages -

4. serous membrane

a. line body cavities that do not open to the outside world always occur in pairs 1) visceral layer 2) parietal layer 3) serous fluid С. peritoneum, pleurae and pericardium

3. mucous membrane

a. lines all body cavities that open to the outside world b. most secrete mucus for moisture and protection

1) Loose Connective Tissue- based on a loose arrangement of fibers

a.) Areolar connective tissue- gel like matrix with all 3 fiber types present. Cells are fibroblasts, lots of open space -wraps and cushions organs, universal packaging tissue B.) adipose (fat) tissue- like areolar in structure and function but store large amounts of nutrients -Adipocytes (fat cells) make up 90% of the tissues mass -matrix is thin, and cells are packed tightly together. - oil (triglyceride) occupies most cell volume, pushing nucleus to far side -as cells give or lose fat, they get larger or smaller -adipose is very vascular -greatest amount is in subcutaneous tissue -acts as shock absorber, insulator and energy site C.) reticular connective tissue- resembles areolar, but only has reticular fibers in the matrix, which makes it more delicate -fibroblasts are called reticular cells - forms internal framework that supports free blood cells in lymph nodes, the spleen and bone marrow

simple columnar epithelia are designed for?

absorption and secretion.

Epithelial tissue is

an innervated, avascular tissue that exhibits polarity. Epithelial tissue is also highly regenerative.

covering and lining epithelium

forms the outer layer of skin, lines the open cavities of the body and covers walls of inner body organs/cavities

mast cell, which produces and secretes?

inflammation-triggering chemicals such as histamine.

simple squamous epithelium are found in areas?

involved in filtration.

the dendrites receive input from?

other cells and send the information to the axon, they are not the metabolic center of the neuron.

the axon:

receives signals from the dendrites and soma and generates an action potential (nerve impulse), thus sending the signal to the next cell. -the transmitting or conductive region of a neuron

Exocrine glands use ducts to?

secrete substances into the external environment (onto the surfaces of the cutaneous and mucous membranes). Note: "exo" means outside.

Transitional epithelium is found in?

the urinary system. It lines the ureters, bladder and proximal part of the urethra-organs that are subjected to distention or stretching as urine passes through or fills them.