1. Lab 1 ANIMAL TISSUES

2. Levels of Organization
Animals are multicellular heterotrophs whose cells lack cell walls.
Most animals exhibit a hierarchical level of organization:
Cells are organized into tissues
Tissues combine to form organs
Organs comprise organ systems

3. What is a tissue?
Group of similar cells that perform a specialized function.
Examples include:
Bone tissue
Blood tissue
Muscle tissue

4. 4 basic types of animal tissue:
Epithelial
Connective
Muscle
Nervous

5. Epithelial Tissue Characteristics:
Cells fit closely together forming continuous sheets
Apical (free) surface covers body surface or lines interior of organs
Basal surface adheres to the basement membrane

6. Epithelial Tissue
Supported by connective tissue
Avascular, but innervated
Have remarkable powers of regeneration
Variety of functions depending on type (protection, absorption, filtration, excretion, secretion)

7. Epithelial Tissue
Classification based on # of cell layers and shape of cells on apical surface.
# of Cell Layers:
Simple – one layer of cells
Stratified – two or more layers
Pseudostratified – simple, but appears stratified

8. Epithelial Tissue Cell shape on apical surface:
Squamous – flattened & scale-like
Cuboidal – box-like
Columnar – tall & column-like

9. Connective Tissue Characteristics:
Most are well vascularized
Consists of widely-spaced cells and fibers embedded in a non-living extracellular matrix
Variety of functions depending on type (support, binding other tissues, transport, defense, storage)

10. Muscle Tissue Characteristics:
Well vascularized
Packed with actin & myosin filaments
Function to contract producing most types of body movements

11. Nervous Tissue Characteristics: Composed of two types of cells:
Neurons – specialized to generate and transmit impulses; amitotic
Neuroglia (glial cells) – protect, support & insulate neurons
Main component of the nervous system (brain, spinal cord & nerves)

12. This week’s lab is devoted to histology (the study of tissues).

13. Exercise A: Epithelial Tissues
Simple squamous epithelium
Location – alveoli of lungs, lining of heart & blood vessels
Function – allows diffusion of materials
surface view
lateral view

14. simple cuboidal epithelium
Exercise A: Epithelial Tissues
Simple cuboidal epithelium
Location – kidney tubules & ducts; ovary surface
Function – secretion & absorption
simple cuboidal epithelium
basement membrane
cross section
longitudinal section

15. Exercise A: Epithelial Tissues
Simple columnar epithelium
Location – lines digestive tract from stomach to the rectum
Function – absorption & secretion

16. Exercise A: Epithelial Tissues
Pseudostratified columnar epithelium
Location – lining of trachea & upper respiratory tract
Function – secretion & propulsion of mucus
cilia
ciliated cell
goblet cell
basal cell
basement membrane
connective tissue

17. stratified squamous epithelium
Exercise A: Epithelial Tissues
Stratified squamous epithelium
Location
keratinized type: epidermis of skin
non-keratinized type: linings of esophagus, mouth & vagina
Function – protection
stratified squamous epithelium
connective tissue
Keratinized
Non-keratinized

18. Exercise B: Connective Tissues
Loose (areolar) connective tissue
Location – widely distributed under epithelia
Function – cushions organs
Gel-like matrix
Collagen fiber
Fibroblast nucleus
Elastic fiber

19. Exercise B: Connective Tissues
Adipose
Location – under skin; around kidneys & eyeballs; in breasts
Function – supports & protects organs; insulates against heat loss; provides reserve fuel

20. Exercise B: Connective Tissues
Dense (fibrous) connective tissue
Location – tendons & ligaments
Function – attaches muscle to bone (tendons) & bone to bone (ligaments)

21. Exercise B: Connective Tissues
Hyaline cartilage
Location – covers ends of long bones; nose, trachea & larynx
Function – support & reinforcement
Chondrocytes sitting in lacunae (cavities)
Matrix packed with collagen fibers

22. Exercise B: Connective Tissues
Bone
Location – bones
Function – support & protection; calcium storage; provides levers for muscles to act on; site of blood cell production
Canaliculi
Central canal
Osteocyte sitting a in lacuna (cavity)
Osteon

23. Exercise B: Connective Tissues
Blood
Location – contained within blood vessels
Function – transport of gases (O2 & CO2), nutrients & metabolic wastes
Red blood cells
Platelet
White blood cells:
neutrophil
monocyte
lymphocyte
Plasma (liquid matrix)

24. Exercise C: Muscle Tissues
Skeletal muscle
Long, cylindrical, multinucleate cells with obvious striations
Location – attached to bones or occasionally to skin
Function – voluntary movement
Nuclei
Striations

25. Exercise C: Muscle Tissues
Cardiac muscle
Branched, uninucleate cells with striations
Location – walls of the heart
Function – contract involuntarily to propel blood
Branched cell
Intercalated disc
Striations

26. Exercise C: Muscle Tissues
Smooth muscle
Tapered, uninucleate, non-striated cells
Location – walls of hollow organs
Function – contract involuntarily to propel materials along internal passageways
Nuclei
Circular layer
Longitudinal layer
Individual muscle cell

27. Exercise D: Nervous Tissue
Neurons
cell body – contains nucleus
cytoplasmic processes:
dendrites – transmit impulses to cell body
axon – transmits impulses from cell body
Neuronal processes
(axons & dendrites)
Neuron nucleus
Neuron cell body
Neuroglia