A&P Chapter 4 - TISSUES

Histology Tissues

Simple Squamous Epithelium

• structure: single layer of flat cells (fried eggs)

• function: protection against friction, diffusion, and filtration

• location: lining serous membranes in body cavities, lining blood vessels and heart

Stratified Squamous Epithelium

• structure: several layers of cells that are progressively flat (lots of fried eggs)

• function: barrier against infection, reduces water loss from the body

• location: outer layer of skin, mouth down through to the esophagus

Simple Cuboidal Epithelium

• structure: single layer of rounded cube-shaped cells (like tadpole eggs)

• function: secretion by the glands and kidney tubules, movement of particles out of the lungs

• location: kidney tubules, glands/ducts, lining of lung bronchioles

Transitional Epithelium

• structure: several layers of stratified that appear mostly cuboidal (like polka dots)

• function: accommodates fluctuations of fluid volume in an organ or tube

• location: lining of bladder, urethra/ureters

Simple Columnar Epithelium

• structure: single layer of tall and narrow cells, contain microvilli (like river)

• function: secretion by stomach and absorption by intestines

• location: stomach, intestines, gallbladder

Pseudostratified Columnar Epithelium

• structure: single layer of tall and thin cells that can reach the free surface. nuclei of these cells appear at different levels and stratified (like coral reefs)

• function: create and secrete mucus onto free surface and remove foreign particles from respiratory passages

• location: lining of nasal sinuses, trachea, and bronchioles of lungs

functions of epithelial tissues?

• act as a barrier and protect underlying tissues

• secrete and absorb substances

• permit passage of substances

functions of connective tissues?

• support and movement

• connect tissues to one another (tendons and ligaments)

• enclose organs and separate layers

three types of cells in connective tissues and their function

• blasts: build the matrix

• cytes: maintain the matrix

• clasts: breakdown matrix for remodeling

components of extracellular matrix

1. ground substance

2. protein fibers

3. fluid

protein fibers of the extracellular matrix

• collagen

  • like a rope

  • strong and inelastic

• reticular

  • fill spaces between tissues and organs

  • form branching networks

• elastic

  • returns to original shape after stretching and decompression

  • resemble coiled springs

components of ground substance of extracellular matrix?

1. hyaluronic acid

2. proteoglycans

3. adhesive molecules

what are the connective tissue propers?

• loose: fewer fibers, more ground substance

  • areolar, adipose, reticular

• dense: more fibers, less ground substance

  • dense regular and irregular

what are the supporting tissues?

• cartilage: semisolid

  • hyaline, fibrocartilage, elastic

• bone: solid, spongy and compact

what are the two fluid tissues?

• blood

• hematopoietic (red and yellow bone marrow)

functions of connective tissue proper

• packing material of the body

• cushions cells

• stabilizes organs

• support epithelium

Areolar Connective Tissue

• structure: fine network of fibers (collagen) with spaces in between (like threads of yarn or string)

• function: loose packing and support

• location: packing between glands, muscles, and nerves. attaches skin to underlying tissues

Adipose Connective Tissue

• structure: little extracellular matrix surrounding cells, large size (like rocks/pebbles)

• function: energy storage, insulation, packing material

• location: subcutaneous (skin) areas, mammary glands

Reticular Connective Tissue

• structure: fine network of irregular arrangement of fibers (like veins in the eyes)

• function: provides structure for lymph nodes and hematopoietic bone marrow

• location: lymph nodes, bone marrow, spleen

Dense Regular Connective Tissue

• structure: composed of collagen fibers running in almost same directions (like waves)

• function: withstanding pulling forces and stretch resistance

• location: tendons (attached to bone) and ligaments (attach bones to each other)

Dense Irregular Connective Tissue

• structure: composed of collagen fibers running in different directions (like storm eye of Jupiter)

• function: strength capable of withstanding stretching in all directions

• location: dermis of the skin, outer covering of body tubes, sheaths

Blood Fluid Connective Tissue

• structure: formed red/white cells and platelets/clotting (like frisbee discs)

• function: transport O2 and CO2, protect the body against infections

• location: within blood vessels

Hematopoietic Fluid Connective Tissue

• structure: numerous blood-forming cells, red marrow

• function: produces new blood cells, red marrow. stores lipids, yellow marrow

• location: within marrow cavities of mostly long bones

Hyaline Cartilage Supportive Tissue

• structure: matrix appears transparent, chondrocytes are found throughout (like swiss cheese)

• function: forms smoother cushion surfaces between joints, growth of long bones

• location: surface of bones, rings of respiratory system, long bones

Elastic Cartilage Supporting Tissue

• structure: matrix contains elastic fibers, also somewhat transparent (like eyeballs)

• function: provides rigidity with flexibility because elastic fibers can return to their original shape after stretching

• location: external ears, auditory tubes, epiglottis

Fibrocartilage Supportive Tissue

• structure: higher numbers of fibers and are arranged in thicker bundles (like hairs on a head)

• function: capable of withstanding pressure, connects structures that can withhold pressure (spine)

• location: intervertebral discs, knee and jaw joints

Compact Bone Supportive Tissue

• structure: hard matrix, lacunae distributed in a circular fashion around a central point (like tree stump)

• function: provide strength and support, forms solid shell that keeps bones from easily breaking or puncturing

• location: outer portions of bones, shafts of long bones

functions of muscle tissue

• contracts and shortens with force

• moves the body and helps to pump blood

Skeletal Muscle Tissue

• structure: fibers that appear striated and banded, cells are large/long and cylindrical, multiple nucleus’

• function: movement of the body under voluntary control

• location: attached to bone or other connective tissue

Cardiac Muscle Tissue

• structure: cylindrical and striation with only single nucleus, branched and connected to each other by intercalated disks with gap junctions

• function: pumps blood for the body and under involuntary control

• location: in the heart

Smooth Muscle Tissue

• structure: not striated, single nucleus, and tapered/cut off at each end

• function: regulates size of organs and allows for flowing of substances/fluid through tubes and organs (digestive tract). under involuntary control

• location: hollow organs such as stomach and intestines, skin and eyes

components of nervous tissue

• neurons and tissue have the ability to produce electrical signals called action potentials

  1. cell body: contains nucleus

  2. axon: conducts impulses away from the cell body. only one per neuron

  3. dendrites: receive impulses from other neurons. can be many per neuron

• glia: supporting cells of the brain, spinal cord, and nerves

  • nourish, protect, and insulate neurons

Nervous Tissue (Neuron)

• structure: consists of dendrites, cell body, and long axon. glial cells surround the neurons

• function: transmit information in the form of action potentials, store information, and evaluate data

• location: brain, spinal cord, ganglia