Bio 180 - Chapter 4: Tissue Level of Organization - Moraine Valley Community College

Tissue

collection of specialized cells and cell products working together to perform a limited number of functions

Epithelial Tissue*

covers exposed surfaces, intestinal passageways, and forms glands

Connective Tissue*

fills internal spaces, provides structural support, transports material, and stores energy

Muscle Tissue

Muscle that is specialized for contraction

Types of muscle tissue

skeletal muscle, cardiac muscle, and smooth muscle

Neural tissue

carries electrical impulses throughout the body

Important characteristics of epithelial tissue

*(high) cellularity*, polarity, attachment, avascularity, *regeneration*

*List the Cell Junctions*

tight junctions,

desmosomes,

gap junctions

Tight Junctions

The lipid portion of the plasma membranes of two cells are tightly bound together by interlocking membrane proteins; so tight, they prevent the passage of water and ions between cells

Gap Junctions

composed of channel called connexons; form narrow passageways that allow small molecules and ions (currents) to pass from cell to cell

Desmosomes

Very strong connections made of CAMs and proteoglycans that can resist stretching and twisting; Keep membranes from separating from one another

What are the epithelial cell classifications?

Squamous

Cuboidal

Columnar

Simple epithelium*

only one layer of cells covers the basements membrane; characteristic of regions where absorption and secretion occur

Stratified epithelium

several layers of cells are present along the basement membrane; generally located in areas that are exposed to chemical and mechanical stresses

pseudostratified columnar epithelium

tissue that consists of a single layer of irregularly shaped and sized cells that give the appearance of multiple layers; found in ducts of certain glands and the upper respiratory tract

What is a good indicator a layer is pseudostratified columnar epithelium?

Cilia

Apocrine Secretion

Part of the cell is broken down and released to secrete sweat, not the whole thing.

Holocrine Secretion

secretions released by cell bursting; mitotic replacement of cells occurs.

Types of secretions of exocrine glands

Serous glands

Mucous glands

serous glands*

secrete a watery secretion that contains enzymes (watery)

mucous glands*

secrete mucins that hydrate to form mucous (viscous)

Mixed Glands

contain more than one type of gland cell

Simple Gland*

A gland that does not have a branching duct; ONE SINGLE DUCT WITHOUT BRANCHING DUCTS

Compounds Gland*

A gland that has at least one branching duct

Connective Tissue

connects epithelium to the rest of the body

Basic components of Connective Tissue

1.Specialized cells - ie. Blood, transports Oxygen

2.Extracellular protein fibers - ie. Blood, makes up a clot

3.Ground substance - ie. Blood, has plasma

Matrix

extracellular fibers and ground substance combined; typically makes up the majority of a connective tissue

Connective Tissue Classifications

Connective Tissue Proper

Fluid Connective Tissue

Supporting Connective Tissue

Connective Tissue Proper & types of cells

Somewhere in-between Fluid and Supporting (ie. fat); *Melanocytes, Adipocytes, and Fibroblasts*

Fluid Connective Tissue & Fiber types

Composed of cells suspended in a watery matrix (ie. blood and lymph); *Collagen fibers, Reticular Fibers, and Elastic Fibers*

Supporting Connective Tissue

Composed of a matrix containing many densely packed fibers

Areolar connective tissue

The least specialized connective tissue type in adults; can distort without damage, and typically occupies areas between the skin and underlying tissues

Adipose tissue

provides padding, absorbs shocks, acts as an insulator, and serves as a packer or filler around structures; majority of this tissue type consists of adipocytes

Reticular Tissue

creates a complex, three-dimensional, stroma; Dominated by reticular fibers

Stroma

houses the parenchyma in the liver, spleen, and kidney (frame of building, scaffolding

Dense regular connective tissue

tightly packed, with collagen fibers parallel to each other (regular - in an order, moving in the same direction

Tendons*

dense regular connective tissue that connect tissue to bone

Ligaments

connect bone to bone, or stabilize the positions of internal organs

Aponeurosis

tendinous sheet that attaches a broad (over a larger area, rather than as a cord), flat muscle to another or to several bones of the skeleton

Dense irregular connective tissue

forms an interwoven meshwork in no consistent pattern that can strengthen and support areas subjected to stresses from many directions

Name a major function of Dense Irregular Connective Tissue

forms the capsule around the liver, spleen, kidneys, and joint spaces

Elastic Tissue

a dense regular elastic tissue dominated by elastic fiber (ie. the tissue that stabilizes the position of the vertebrae)

Interstitial Fluid

extracellular fluid that specifically surrounds cells

Lymph

Fluid that is formed as interstitial fluid enters the lymphatic vessels

Lymphatic Vessels

specialized vessels responsible for sending lymph to lymphatic tissue and specialized organs throughout the body

Cartilage

a firm gel that contains polysaccharides derivatives called chondroitin sulfates

Chondrocytes*

the only cell type in the cartilage matrix; occupy small chambers known as *lacunae*

Is cartilage avascular or highly vascular?

Avascular - all exchange of nutrients and waste products must occur through diffusion

Hyaline Cartilage*

the most common type of cartilage; contains closely packed collagen fibers (fibers may not be seen but are present)

Examples of Hyaline Cartilage** (2-3)

Nasal Cartilage

Articular cartilages

Connections between sternum and ribs

Elastic Cartilage**

contains numerous elastic fibers that make it extremely resilient and flexible

Examples of Elastic Cartilage** (2-3)

•Auricle (external flap of the external ear)

•Epiglottis - leaf-like structure from the anterior view( Folds as necessary - elastic)

•The auditory tube (middle ear cavity passageway)

Fibrocartilage*

has little ground substance and a matrix that is dominated by densely interwoven collagen fibers making it durable and tough

Fibrocartilage does a good job of resisting compression and preventing bone-to-bone contact

Name multiple examples of Fibrocartilage** (ALL 3)

•Pubic symphysis

•Intervertebral discs

•Menisci of the knee

Bone (osseous tissue)

tissue type that is the basis of the skeletal system

How much of the bone matrix is calcium phosphate, and to a lesser extent, calcium carbonate?

two-thirds

How much of the bone matrix is dominated by collagen fibers?

One-third

Mucous membrane (mucosa)

line passageways that communicate with the exterior; Has to do with things passing

in and out of the body

Serous Membrane

lines the sealed, internal subdivisions of the ventral body cavity (cavities not open to the exterior)

Name the different types of serous membranes

Pleura

Peritoneum

Percardium

What are the portions of the serous membrane?

Parietal

Visceral

Parietal Portion (Serous membrane)*

lines the inner surface of the cavity

Visceral Portion (Serous Membrane)

lines the outer surface of the visceral organs - deep

Fascia

connective tissue layers and wrappings that support and surround organs

Superficial Fascia

layer of areolar tissue and fat that separates skin from the underlying tissues and organs; provides insulation and padding

Deep Fascia

made of dense irregular connective tissue; can resist forces in many directions; bound to tissue capsules, tendons, and ligaments

Subserous Fascia

between deep fascia and the serous membranes that line body cavities

Deepest; binds to body cavities

Types of Muscle Tissue

Skeletal

Smooth

Cardiac

Characteristics of Muscle Tissue*

multinucleated, meaning they have many nuclei

Striated (ribbed)

long and slender

Cardiac Muscle

located in the heart; composed of the smaller cell type, cardiocyte

Characteristics of Cardiac Muscle**

Typically, each cardiocyte has one centrally located nucleus

*Intercalated discs* - specialized connections between cardiac muscle cells comprised of desmosomes, proteoglycans, and gap junctions

Very limited in terms of being able to repair itself

Striations

Smooth Muscle

located in the walls of blood vessels, around hollow organs, and in layers of the respiratory, cardiovascular, digestive, and reproductive tracts

Characteristics of Smooth Muscles

small, *spindle shaped cells*, that typically taper at the end and contain one nucleus (nuclei tend to be spindle-shaped)

Typically not striated

Neural Tissue

specialized for conduction of electrical impulses from one region of the body to another

Cell types of neural tissue

Neurons**

Neuroglia

What are neurons made up of**

Axon

Dendrites

Cell Body