1. Homeostasis and the Organization of the Body
Chapter 32

2. Homeostasis State of balance within the body
Maintaining body conditions within set limits

3. Regulating body temperature
Endotherms (“inside heat”)
Produce heat by metabolic reactions
Ex. Birds and mammals
Ectotherms (“outside heat”)
Obtain heat from environment (i.e. basking in the sun)
Ex. Reptiles, amphibians, most fish, invertebrates

4. Warmer temperatures = higher metabolic rate
Cold lizards
Hummingbirds
Heat stroke and frostbite in endotherms

5. Feedback Systems Method of maintaining internal environment
Negative feedback – method for keeping body conditions within a normal range and maintaining homeostasis
Positive feedback – substance or condition that acts within a system to produce more of the same activity

6. Negative Feedback

7. Negative Feedback

8. Negative Feedback

9. Positive Feedback

10. Comparing the Two Types of Feedback Mechanisms

11. How is the animal body organized?

12. Tissues are composed of similar cells
4 Major Categories
1. Epithelial tissue
2. Connective tissue
3. Muscle tissue
4. Nervous tissue

13. Tissue Type 1: Epithelial tissue
Forms protective covering for the body
Covers the outside of the body (skin)
Lines the body cavities, hollow organs (i.e. digestive, respiratory, urinary, reproductive), and ducts (i.e. blood vessels)

14. Classification of Epithelial Tissue
Based on shape and layers
Simple epithelium
One layer
Ex. Found in digestive, respiratory, and circulatory system
Stratified epithelium
Multiple layers
Ex. Found in mouth and skin
Covered with many layers of dead cells
These cells and others below contain keratin
Makes skin water-resistant, flexible, and tough

15. Classification of Epithelial Tissue

16. Simple Squamous Epithelium
APSU OU

17. Simple Columnar Epithelium
Goblet cell - mucus-secreting gland cell
King, David SIUC.

18. Simple Cuboidal Epithelium

19. Stratified Squamous Epithelium
NKU

20. Pseudostratified Ciliated Columnar Epithelium
Palomar

21. Glands
Single cells (i.e. goblet cells) or groups of cells (i.e. salivary, mammary, sweat) that secrete substances outside the cell
2 types of glands
Exocrine Glands
Endocrine Glands

22. Exocrine Glands
Secrete non-hormonal substances into a body cavity or onto body surface usually through a duct
Sweat glands
Sebaceous glands (oil glands)
Salivary glands
Exocrine glands in stomach and small intestine

23. Endocrine glands Lack ducts
Secrete hormones that diffuse into nearby capillaries
Hormones – chemical produced that are transported by bloodstream to regulate activity of cells

24. Tissue Type 2: Connective Tissue
Main function is to support and bind other tissues
Cells are embedded in a matrix of extracellular substances
Fluid
Flexible proteins
Collagen – the most abundant
4 main types:
Liquid connective tissue
Soft connective tissue
Fibrous connective tissue
Hard connective tissue

25. Liquid Tissue Cells are suspended in a fluid matrix Ex. Blood
Cellular portion
Red blood cells
White blood cells
Platelets (cell fragments)
Extracellular portion
Plasma (fluid)

26. Soft Connective Tissue
Loose Connective Tissue
Cells (fibroblasts) in jellylike matrix
Cells secrete protein fibers and collagen protein
Most common type of tissue in the body
Found in membranes around vessels and organs, between muscles, and under skin
Adipose (fat) Tissue
Stores fat for energy
Serves as insulation
Serves as protective padding for joints and organs

27. Soft Connective Tissue
Loose connective tissue
Adipose tissue

28. Fibrous (Dense) Connective Tissue
Cells = fibroblasts
Contains collagen fibers
Often densely packed in a parallel arrangement which gives flexibility and strength
Ex. Tendons (connects muscle to bones)
Ex. Ligaments (connects bone to bone)

29. Hard Connective Tissue
Cartilage
Thick, nonliving matrix
Matrix composed of collagen which is produced by the cartilage cells
Flexible and resilient
Covers ends of long bones, forms framework for respiratory passages, supports ears and nose, spinal discs
Bone
Matrix hardened by calcium deposits
Forms in concentric circles around a central canal (contains blood vessels)

30. Hard Connective Tissue
Cartilage
Bone

31. Tissue Type 3: Muscle Tissue
Produces movement by contraction
Able to shorten and relax
3 types of muscle tissue
Skeletal muscle
Cardiac muscle
Smooth muscle

32. Skeletal Muscle Voluntary muscle Heavily striated
Caused by fibrous proteins in the muscle cells
Produces movement of the skeleton

33. Cardiac Muscle Located only in the heart Involuntary muscle
Cells connected by gap junctions through which electrical signals spread through heart
Coordinates cell contraction

34. Smooth Muscle Also called visceral muscle Involuntary Not striated
Produces slow, sustained contractions
Found in walls of digestive tract, uterus, bladder, large blood vessels

35. Tissue Type 4: Nervous Tissue
Makes up brain, spinal cord, nerves
Body’s communication system
2 types of cells
Neurons
Generate electrical signals
Conduct signals to other neurons, muscles, glands
Neuroglial (“glue”) cells
Surround, support, electrically insulate, and protect neurons
Regulate composition of interstitial fluid in nervous system

36. Nervous Tissue Cells General structure of a neuron
1 neuron surrounded by smaller neuroglial cells

37. Organs include 2 or more tissues

38. Skin Protects body against infections and water loss
Helps maintain homeostasis
Contains outer layer of epithelial tissue underlain by connective tissue which contains blood vessels, nerves, muscle (sometimes), glands, and adipose

39. Skin

40. Jejunum (small intestine) Cross-section

41. Three Embryonic Germ (Tissue) Layers

42. Body Cavities

43. Directional Terms

44. Directional Terms

45. Organ Systems
Consists of 2 or more organs working together to perform common function

46. 11 Organ Systems

47. 11 Organ Systems

48. THE END