Anatomy Chapter 5 Saladin

Histology or microscopic anatomy

The study of tissues and how they are arranged into organs

The four tissue classes

The variations within each class; how to recognize tissue types microscopically and relate their microscopic anatomy to their function; how tissues are arranged to form an organ; how tissues change as they grow, Shrink, or change from one tissue type to another over the life of the individual; and modes of tissue degeneration and death

Tissue

Is a group of similar cells and cell products that arise from the same region of the embryo and work together to perform a specific structural or physiological role in an organ.

Matrix

extracellular material that surrounds the cell. composed of fibers, proteins, ground substance, tissue fluid, or interstitial fluid

Ground substance

Contains water, gases, minerals, nutrients, wastes, hormones, and other chemicals

Summary of matrix and tissue

A tissue is composed of cells and matrix and the matrix is composed of fibers and ground substance

The four primary tissue

Epithelial, connective, nervous, and muscular

Epithelial Tissue or Epithelium

CLOSELY spaced cells that cover organ surfaces, form glands, and serve for protection, secretion, and absorption. (Epidermis, Digestive tract, Liver, gall bladder

Connective Tissue

Has MORE matrix than cell volume, often specialized to support, bind, and protect organs. (Blood, Cartilage and Bone, Tendons and Ligaments)

Nervous Tissue

Contains EXCITABLE cells specialized for rapid transmission of coded information to other cells. (Brain, Spinal Cord, Nerves)

Muscular Tissue

ELONGATED excitable muscle cells specialized for contraction. (Skeletal muscles, Heart, Viscera walls)

3 primary germ layers

Ectoderm, Endoderm, and Mesoderm

ectoderm

outer layer that gives rise to the epidermis and nervous system

endoderm

inner layer that gives rise to the mucous membranes of the digestive and respiratory tract.

mesoderm

middle layer of more loosely organized cells

mesenchyme

protein fibers created from mesoderm. Give rise to muscle, bone, and blood among other tissues

histological sections

tissue preparations mounted on microscope slides

longitudinal section

A tissue cut on its long, vertical axis

Cross section or Transverse Section

a tissue cut horizontally

oblique section

a tissue cut diagonally

smear

tissue rubbed across the slide

spread

tissue is laid on the slide

basement membrane

a layer of tissue between an epithelium and connective tissue

basal surface

the surface of an epithelial that faces down toward the basement membrane

apical surface

the surface of an epithelial that faces up toward the internal cavity

difference between simple and stratified epithelium

simple epithelia cells touch the basement membrane , whereas in stratified epithelium some cells rest on top of other cells and don't contact the basement membrane

Simple Epithelia

has only one layer of cells (Simple squamous, simple cuboidal, simple columnar, pseudo stratified columnar)

goblet cells

produce protective mucous coatings over the mucous membranes

Stratified Epithelia

range from 2 to 20 or more layers of cells (Stratified Squamous, Stratified Cuboidal, Stratified columnar, transitional)

pseudostratified columnar epithelium

shorter cells are covered by taller ones

transitional epithelium

Contain umbrella cells

Stratified Squamous Epithelium

The most widespread epithelium in the body.

Exfoliation

When stratified squamous cells daughter cells push toward the surface and become flatter and push farther upward, until they finally die and flake off.

Keratinized epithelia

cells found in the epidermis covered with a layer of dead compressed cells (The Skin)

Non-keratinized epithelia

lack the surface layer of dead cells. Abrasion resistant, moist, and slippery (Tongue, Esophagus, and Vagina)

Umbrella cells

A term for a multinucleated superficial cell of the bladder's transitional

Simple squamous epithelium

located in external surface of small intestine, air sacs of lungs, kidneys, inner lining of heart and blood vessels, and serous membranes of stomach. Allows rapid diffusion or transport of substances through membrane. secrets lubricating serous fluid

Simple cuboidal epithelium

centrally placed nuclei located in the liver, thyroid, mammary, salivary, kidney tubules, and bronchioles. with a brush border of microvilli in some kidney tubles; ciliated in bronchioles of lung

Simple columnar epithelium

located on the inner lining of stomach, intestines, gallbladder, uterus, and uterine tubes; some kidney tubles. absorbs and secrets mucus and moves egg and embryo in uterine tube.

pseudostratified columnar epithelium

located in the respiratory tract from nasal cavity to bronchi; portions of male urethra

stratified cuboidal epithelium

*Two or more cell layers; surface cells square

*Secretes sweat; produces sperm and hormones

*Sweat gland ducts; ovarian follicles and seminiferous tubules

Keratinized Stratified Squamous

*Multilayered epithelium covered with dead squamous cells, packed with keratin

-epidermal layer of skin

*Retards water loss and barrier to organisms

Nonkeratinized Stratified Squamous

*Multilayered surface epithelium forming moist, slippery layer

*Tongue, oral mucosa, esophagus and vagina

Transitional Epithelium

*Multilayered epithelium surface cells that change from round to flat when stretched

-allows for filling of urinary tract

-ureter and bladder

Exocrine Glands

-Secrete substance onto body surface or into body cavity

-Have ducts

-E.G., salivary, mammary, pancreas, liver

Endocrine Glands

-Secrete product into blood stream

-Either stored in secretory cells or in follicle surrounded by secretory cells

-Hormones travel to target organ to increase response

-No ducts

Connective Tissue

*Widely spaced cells separated by fibers and ground substance

*Most abundant and variable tissue type

*Functions

-connects organs

-gives support and protection (physical and immune)

-stores energy and produces heat

-movement and transport of materials

Cells of Connective Tissue

*Fibroblasts produce fibers and ground substance

*Macrophages phagocytize foreign material and activate immune system

-arise from monocytes (WBCs)

-Neutrophils wander in search of bacteria

-Plasma cells synthesize antibodies

arise from WBCs

*Mast cells secrete

-heparin inhibits clotting

-histamine that dilates blood vessels

*Adipocytes store triglycerides

Most Important

Muscle Tissue

*Elongated cells stimulated to contract

*Exert physical force on other tissues

-move limbs

-push blood through a vessel

-expel urine

*Source of body heat

3 histological types of muscle

skeletal, cardiac and smooth

Skeletal Muscle

Many nuclei in muscle cells, only seen in this muscle. Striated, long threadlike cells, multinucleated

Cardiac Muscle

Only found in the heart, single nucleus, one specialized fiber intercalated discs. Branch cells, striated, uninucleated

Smooth Muscle

fusiform shape, single nucleus place in center, found in internal organs, nerves suppling it to turn food

Intercellular Junctions

All cells (except blood) anchored to each other or their matrix

Membrane Types

*Cutaneous

*Synovial

*Serous

Cutaneous membrane = Skin

stratified squamous epithelium over connective tissue

Synovial membrane= lines joint cavities

connective tissue layer only, secretes synovial fluid

Serous membrane(Serosa)- Internal membrane

-simple squamous epithelium over areolar tissue, produces serous fluid

-covers organs and lines walls of body cavities

Tissue Growth

-Hyperplasia

-Hypertrophy

-Neoplasia

Hyperplasia

tissue growth through cell multiplication

Hypertrophy

*enlargement of preexisting cells

-muscle grow through exercise

Neoplasia

growth of a tumor (benign or malignant) through growth of abnormal tissue

Changes in Tissue Types

*Tissues can change types

*Differentiation

*Metaplasia

Differentiation

*unspecialized tissues of embryo become specialized mature types

-mesenchyme to muscle

Metaplasia

*changing from one type of mature tissue to another

-simple cuboidal tissue before puberty changes to stratified squamous after puberty

Stem Cells

Undifferentiated cells with developmental plasticity

Embryonic stem cells

*totipotent (any cell type possible)

*Pluripotent (tissue types only possible)

Adult stem cells

(undifferentiated cells in tissues of adults)

totipotent- embryonic stem cells

-(any cell type possible)

-source = cells of very early embryo

unipotent- Adult stem cells

(only epidermal cells produced)

Pluripotent - embryonic stem cells

-(tissue types only possible)

-source = cells of inner cell mass of embryo

multipotent- Adult stem cells

(bone marrow producing several blood cell types)

Tissue Shrinkage and Death

*Atrophy

*Necrosis

*Apoptosis

Periosteum

A bone as whole is covered with tough fibrous layer

Portion of blood

Blood plasma is best defined as the liquid

Blood

The fluid connective tissue that travels through vessels

Names of the formed elements of blood

-platelets

-erythrocytes

-leukocytes

Location where adipose is found

- Within the orbits

-Within the breast

-Deep to dermis of the skin

Plasma

Liquid portion of the blood

Cartilage

relatively stiff connective tissue with a rubbery matrix

Where would you find spongy bone?

-In head of long bones

-Within the interior of flat and irregular bones

Lacuna

A small cavity in a tissue such as a bone or cartilage

Chondroblast

Within cartilage, cells secrete cartilage matrix

Two types of bone tissues

spongy and compact

Formed elements

The cells and cell fragments of blood or lymph

Erythrocyte

Another name for red blood cell and most abundant type of formed element

Chondrocyte

A cartilage cell that has become enclosed in a lacuna in the cartilage matrix

Mucus

Wineglass-shapped goblet cells, found within some nonsecretory epithelia

Mesenchyme

Give rise to muscle, bone, and blood

Macrophages

- Destroy dead or dying self cells

-Engulf foreign particles

- Activate the immune system when they encounter antigens

Cell Types found in fibrous connective tissue

- Mast cells

- Fibroblasts

- Macrophages

Extracellular Fluid

any body fluid that is not contained in the cells

Osseous (Bone) Tissue

Spongy & Compact

Mitosis

The cells of the basal layers of stratified epithelium undergo, allowing more epithelial cells to be produced