1. Histology
Ms. Levensailor

2. Animal Tissues Hierarchy: cells  tissues  organs  organ systems
Tissues: groups of cells with a common structure and function.
Held together by :
Sticky substance
Woven together like a fabric
From a Latin word meaning “weave”
Note: Use the provided graphic organizer to take notes.

3. 4 Main Categories Epithelial tissue Connective tissue Muscles tissue
Nervous tissue
With your face partner brainstorm the location and function of these tissue based on prior knowledge or their names.

4. Epithelial Tissue
Cover the outside of the body and lines organs/cavities within the body.
Closely joined/packed cells.
Functions as a barrier against injury, invading organisms, fluid loss.
Structure matches function!

5. Epithelial Tissue Free surface is exposed to air or fluid.
Cells at the base of the barrier are attached to the basement membrane (dense layer of extracellular material).
Criteria for Classification:
Number of cell layers.
Shape of the cells on the free surface.

6. Number of cell layers Simple: single layer of cells.
Stratified: multiple tiers of cells.

7. Shape of Cells Cuboidal: like dice Columnar: like long bricks
Squamous: like flat floor tiles

8. Put the words together. . .

9. Epithelial Tissue

10. Structure & Function Simple squamous: relatively leaky.
Used for exchange of materials (diffusion)
Linings of blood vessels and air sacs of the lungs.
Stratified squamous: regenerates rapidly by cell division.
Used as replacements for cells that are continually sloughed off.
Outer skin linings like the esophagus.

11. Structure & Function Columnar epithelia: large cytoplasmic volume.
Located where secretion or active absorption of substances are important.
Stomach and intestines.
Cuboidal cells: specialized for secretion.
Kidney tubules, thyroid gland, and salivary glands.

12. Check for Understanding
Grab a whiteboard and marker.
What type of tissue is this?
Simple squamous

13. Check for Understanding
What type of tissue is this?
Stratified squamous

14. Check for Understanding
What type of tissue is this?
Simple cuboidal

15. Check for Understanding
What type of tissue is this?
Stratified cuboidal

16. Check for Understanding
What type of tissue is this?
Simple columnar

17. Connective Tissue Function: to bind and support other tissues.
Sparse population of cells scattered through an extracellular matrix.
Matrix: nonliving, web of fibers embedded in a homogeneous substance (liquid, jelly, or solid).
Secreted by the cells of the connective tissue.

18. Connective Tissue Major types: Loose connective tissue*
Adipose tissue*
Fibrous connective tissue
Cartilage
Bone*
Blood
*These will be our focus.

19. Loose Connective Tissue
Used as:
Binding to attach epithelia to underlying tissue.
Packing material to hold organs in place.
Made of a loose weave of fibers.
3 types of fibers:
Collagenous
Elastic
Reticular

20. Loose Connective Tissue

21. Adipose
Specialized connective tissue: stores fat in cells throughout the matrix.
Functions:
Pads and insulates the body.
Stores fuel molecules.
Cells contain large fat droplet that swells when fat is stored.

22. Bone Mineralized connective tissue.
Cells called osteocytes: deposit a matrix of collagen & release calcium phosphate.
Combination makes bone harder than cartilage without being brittle.

23. Check for Understanding
What type of tissue is this?
Loose Connective Tissue

24. Check for Understanding
What type of tissue is this?
Bone

25. Check for Understanding
What type of tissue is this?
Adipose

26. Muscle Tissue Composed of long excitable cells.
Capable of contraction.
Large numbers of microfilaments run parallel within cytoplasm of cells.
Made of actin and myosin (contractile proteins).

27. Types of Tissue
Skeletal
Cardiac
Visceral (smooth)

29. Skeletal Responsible for voluntary movements of the body.
Adults have a fixed number of muscle cells.
Weight lifting does not increase cell number, just enlarges cells.
Also called striated muscle : overlapping microfilaments give the cells a striped appearance.

30. Cardiac Forms the contractile wall of the heart.
Striated, but branched.
Causes rhythmic beating and contractions of the heart (uncontrollable).

31. Visceral (smooth) Lacks cross-striations.
Found in: Walls of the digestive tract, bladder, and arteries.
Involuntary: not subject to conscious control.

32. Muscle Tissue Review

33. Check for Understanding
What type of tissue is this?
Smooth muscle

34. Check for Understanding
What type of tissue is this?
Cardiac muscle

35. Check for Understanding
What type of tissue is this?
Skeletal muscle

36. Nervous Tissue Senses stimuli and transmits signals.
Functional unit is the neuron.
Consists of:
a cell body
Nerve processes (two or more appendages)
Dendrites: process impulses toward the cell body
Axons: transmit impulses away from the cell body

37. Nervous Tissue