1. Lab 2- Body Tissues rev 7011
Tissue: group of cells that are similar in structure and perform a common or related function
4 primary tissue groups
Epithelium
Connective
Muscle
Nervous

2. Tissues combine to form Organs Organs combine to form Organ Systems
Lab 2-Tissues
Tissues combine to form Organs
Organs combine to form Organ Systems
organ systems combine to form the Organism (humans)

3. Epithelial tissues also
Lab 2-Tissues
Epithelial Tissue--sheet of cells that covers a body surface or lines a body cavity; helps form boundaries between different body environments
examples: skin, lining of mouth, lining of digestive tract, etc.
Epithelial tissues also
protect underlying tissues

4. reduce friction because they are smooth
Lab 2-Tissues
reduce friction because they are smooth
epithelial tissue lines the blood vessels and thus helps blood flow more easily
absorb epithelium
filter which lines the
excrete kidneys perform
secrete all these functions
sensory reception

5. Some epithelial tissues form glands
Lab 2-Tissues
Some epithelial tissues form glands
glands are epithelial tissues that are specialized to synthesize and secrete a product
Characteristics of Epithelial Tissue
1. Cells are packed closely together
2. One surface of the tissue is free while the other surface is attached to the underlying connective tissue by the basement membrane

6. 3. Epithelial tissues tend to be given 2 names-
Lab 2-Tissues
3. Epithelial tissues tend to be given 2 names-
first name indicates the number of cell layers present
one layer of cells is called simple epithelium
typically found where absorption and filtration occur and a thin epithelial barrier is desirable
many layers--stratified epithelium
common in high-abrasion areas where protection is important i.e. lining of the mouth, skin surface
second name describes the shape of the cells

7. 4. Cells occur in 3 types squamous--thin and flat cells
Lab 2-Tissues
4. Cells occur in 3 types
squamous--thin and flat cells
forms the thinnest possible layer for diffusion & filtration
look like a pancake when viewed from the side
mostly found in air sacs of lungs, kidney glomeruli, lining of heart, blood vessels, and lymphatic vessels
cuboidal--cube or rounded cells (about as tall as are wide)
major function is secretion but may also be involved in absorption
line the ducts of many glands
has round shaped nucleus which stains very darkly

8. columnar--cylindrical cells (tall and column shaped)
Lab 2-Tissues
columnar--cylindrical cells (tall and column shaped)
tall cell with oval shaped nucleus
mostly associated with absorption, secretion of enzymes and mucous, and movement of materials (ciliated cells)
line the stomach, small and large intestines and a few ducts
these tissues may also have microvilli, cilia, or goblet cells (secrete mucus--a thick fluid which lubricates tissues and traps bacteria, viruses and irritating particles)
line small bronchi, uterine tubes

9. Helpful hints: the shape of the nucleus matches the shape of the cell
Lab 2-Tissues
Helpful hints:
the shape of the nucleus matches the shape of the cell
remember this when you are trying to identify the type of epithelial cell
cell membranes don’t stain well so you may not see them.
Count the number of cells by looking for the cell nucleus

10. Connective Tissue Lab 2-Tissues
found everywhere in the body
Major functions:
1. Binding and support
2. Protection
3. Insulation/storage of fat
4. Transportation of substances within the body

11. Types of Connective tissue:
Lab 2-Tissues
Has comparatively few cells and a lot of non-living matter (called the matrix)
Types of Connective tissue:
Fibrous-connects various body parts; provides strength, support and flexibility
consists of several types of fibers:
Collagen--provides strength and slight flexibility
Elastic--very flexible; can stretch without breaking
Reticular--serves as framework for some organs; fiber flexibility is between elastic and collagen fibers

12. Areolar or Loose connective tissue most common type
Lab 2-Tissues
Fibrous connective tissues are subclassified according to the density and arrangement of their fibers:
Areolar or Loose connective tissue
most common type
contains collagen fibers and elastic fibers in an irregular pattern; is very flexible but not strong
usually found below the skin, between muscles, and around nerves and organs

13. specialized for fat storage
Lab 2-Tissues
Adipose (Fat) tissue
specialized for fat storage
has few connective tissue fibers; primarily made up of fat cells (large, round cells which look empty but really contain an oil droplet which takes up most of the cell and pushes the nucleus to one side)
Primary role is energy storage
also acts as a shock absorber and as an insulator
forms a protective layer around internal organs
Found below skin, around various organs, and around certain muscles

14. Dense White Fibrous Connective Tissue
Lab 2-Tissues
Dense White Fibrous Connective Tissue
fibers are densely packed and run in the same direction
is very strong when stress is in the same direction as the fibers run
has few blood vessels
functions to bind, protect and connect
primarily attaches muscles to bones or to other muscles, bones to bones
usually found in tendons, ligaments and joint capsules

15. Is a specialized connective tissue
Lab 2-Tissues
Hyaline Cartilage
Is a specialized connective tissue
consists primarily of densely packed collagen fibers which contain water
Because of the high water content, cartilage provides firm support, cushioning and flexibility
Found at the connection of the ribs to the sternum, covering of bones at moveable joints, the tip of the nose

16. REMINDER Lab 2-Tissues
There are 7 slides--3 epithelial, 4 connective tissue
Start with the 4x lens, however you will not see actual tissue until you reach the 40x lens
You will likely need to move the slides around to find the tissue you want to draw.
Slides may contain a variety of tissue types.
The lung slide has simple, squamous epithelial tissue
the white fibrous tissue slide has dense connective tissue
Use the color photos on the charts in the back of the room to help you identify the slides

17. INTEGUMENTARY SYSTEM (also known as SKIN)
Functions: --outer covering of the body
protects from dehydration
protects from injury
protects against invasion by bacteria and viruses
helps regulate body temperature
synthesizes vitamin D
Sensory awareness: receptors for touch, vibration, pain and temperature provide information about the environment

18. epidermis: outermost layer of stratified squamous epithelial tissue
Lab 2-Tissues
Skin consists of
epidermis: outermost layer of stratified squamous epithelial tissue
made up of 5 sub-layers: stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale layers
most epidermal cells are keratinocytes.
Scattered among these in the deepest layers are melanocytes which give the skin its color

19. Lab 2-Tissues
Dermis: inner layer of fibrous connective tissue and all structures embedded within it
composed of two sub-layers
this layer “binds” the body together
richly supplied with nerve fibers, blood vessels, and lymphatic vessels

20. Lab 2-Tissues
Hypodermis: supportive layer consisting of loose connective tissue containing fat cells
also called subcutaneous tissue or superficial fascia
anchors the skin to underlying structures (primarily muscles)
is flexible so the skin can move and bend
its fat cells insulate against excessive heat loss and cushion against injury

21. Appendages of the Skin Sweat glands Ceruminous or wax glands
Lab 2-Tissues
Appendages of the Skin
Sweat glands
Ceruminous or wax glands
Sebaceous or oil glands
Hairs are flexible strands produced by hair follicles that consist largely of dead, keratinized cells
Nails: a scale like modification of the epidermis that forms a clear protective covering on the dorsal surface of the ends of fingers and toes

22. REMINDER, page 1 Lab 2-Tissues
1. All skin identification questions will be based on the model; you will not need to identify any skin slides for the practical exams.
There are "answer keys" next to the models however they tend to use the Latin names of the structure and may be confusing to you.
The answer keys may have been moved and may no longer be next to the correct model.
It may be easier to use pictures in the text, lab manual, or on charts to help you identify structures.

23. REMINDER, page 2 Lab 2-Tissues
2. Do not do any of the activities on page 34.