1. Biology, 9th ed, Sylvia Mader
Chapter 33
Unit 5
Animal Organization & Homeostasis
Dynamic Homeostasis

2. Unit Main Ideas – Think/Pair/Share
What is Homeostasis? How is homeostasis different in single-celled organisms vs. multicellular organisms? What unique challenges to maintaining homeostasis do multicellular organisms have to address?

3. Homeostasis Introduction
Homeostasis is the maintenance of a constant internal environment. Every living thing must maintain homeostasis by regulating body temperature, level of food/water, level of needed gases, etc. Death results when homeostasis is not maintained

4. Homeostasis in Single vs Multi-Celled
Single Celled Organisms must take care of all aspects of homeostasis alone. The organelles within the single cell must regulate water, air, food, pH, and temperature. It has no cells to help, but it also does not have to coordinate anything.
Multi-Cellular Organisms are able to maintain homeostasis in teams of specialized cells called tissues. Each cell only has one job (digestion, transport, etc). However, this means they need to be able to coordinate their efforts, so they have to be able to communicate with one another.

5. Homeostasis in Single vs Multi-Celled
Organization helps multi- cellular organisms improve cell efficiency and coordination
Cells  Tissues  Organs  Organ systems  Organism

6. REVIEW: Levels of Organization
Tissue - Group of similar cells performing a similar function
Organ - Group of tissues performing a specialized function
Organ System - Collection of several organs functioning together
Organism - A collection of organ systems

7. Anatomy and Physiology
In order to understand how multicellular organisms function, we need to understand how they are put together.
Anatomy – The study of the specific parts of a multicellular organism (e.g. What is a Kidney?)
Physiology – the study of the function of the specific parts of a multicellular organism (e.g. How does the kidney work?)

8. Anatomy – Relevant Parts
Major Types of Tissue
Epithelial tissue covers body surfaces and lines body cavities. (skin)
Connective tissue binds and supports body parts. (tendons)
Muscular tissue causes motion in body parts. (biceps)
Nervous tissue responds to stimuli and transmits impulses for communication/control. (brain)

9. Epithelial Tissue Epithelial tissue:
Forms a continuous layer over body surfaces
Lines inner cavities
Forms glands
Covers abdominal organs

10. Epithelial Tissue Example
Squamous epithelium is composed of flat cells (e.g., air sac linings of lungs, walls of capillaries).

11. Epithelial Tissue Example
Cuboidal epithelium has cube- shaped cells.

12. Epithelial Tissue Example
Columnar epithelium has elongated cells that resemble pillars or columns (e.g., small intestine). Used for absorption

13. Figure 33.1d

14. Special Epithelial Tissues
Ciliated Epithelia - cells are covered with cilia (e.g., lining of human respiratory tract).
Cilia can bend and move material over the surface of the epithelium.
Glandular Epithelia - can be unicellular or have multicellular glands.
Glands are a single cell or a group of cells that secrete a chemical signal into the body; two types:
Exocrine glands secrete their products into ducts or directly into a tube or cavity.
Endocrine glands secrete their product directly into the bloodstream.

15. Connective Tissue
Connective tissues bind and connect cells together

16. Diagram of Fibrous Connective Tissue

17. Special Connective Tissue
Adipose Tissue
Fat cells; stores energy, insulates the body, and provides padding
Cartilage
Classified according to type of collagen and elastic fibers found in the matrix
Cartilage cells (chondrocytes), lie in small chambers (lacunae) in the matrix

18. Connective Tissue Examples

19. Transports nutrients and oxygen to cells
Figure 33.4
Blood - Actually a connective tissue in which cells are embedded in a liquid matrix (plasma)
Red blood cells - erythrocytes
White blood cells - leukocytes
Transports nutrients and oxygen to cells
Removes carbon dioxide and other wastes

20. Muscular Tissue
Contractile cells containing actin and myosin filaments (cytoskeleton fibers made to contract and release) used for movement
Types
Skeletal Muscle
Voluntary - Long, striated fibers
Smooth Muscle
Involuntary - No striations
Cardiac Muscle
Involuntary, but more similar in structure to skeletal muscle

21. Muscular Tissue

22. Nervous Tissue
Nervous Tissue is used for fast cell to cell communication
Made mostly of cells called neurons that function through electrical impulses

23. Nervous Tissue Nervous system has three functions
Sensory input – receive stimulus
Sensory receptors detect changes in the environment
Transmit info to the spinal cord
Data integration – make a decision
Spinal cord and brain integrate information
Decision is made regarding appropriate response
Motor output – respond to stimulus
Response is transmitted to effector (reactionary cells, e.g. muscles)
Effector initiates actual response

24. Neurons and Neuroglia
Long axons and dendrites form neuron fibers; bound by connective tissue, they form nerves.

25. Organ Systems
The organ systems of the human body contribute to homeostasis by linking organs that form a specific task
The digestive system
Takes in and digests food
Provides nutrients
The respiratory system
Adds oxygen to the blood
Removes carbon dioxide

26. Organ Systems The Excretory (Liver and Kidneys) System
Store excess glucose as glycogen
Later, glycogen is broken down to replace the glucose used
The hormone insulin regulates blood sugar
Creates bile to digest fat
(Kidneys) excrete wastes and salts to regulate water level

27. Organ Systems The circulatory system The nervous system
Communicates and controls body
The circulatory system
Transports oxygen and nutrients throughout the body

28. Organ Systems The integumentary system The immune system
The skeletal system
Provide support and protection
The integumentary system
Production of hormones and communication signals
Provides protection
The immune system
Protection from disease

29. Positive and Negative Feedback Regulation
Controlling the function of Organ Systems
Positive and Negative Feedback Regulation

30. Negative Feedback Homeostatic Control
Partially controlled by hormones (and)
Ultimately controlled by the nervous system
Negative Feedback is the primary homeostatic mechanism that keeps a variable close to a set value (e.g. constant temperature)
Sensor detects change in environment
Regulatory Center activates an effector
Effector reverses the change
Negative = NO CHANGE ALLOWED

31. Negative Feedback Mechanisms: Simple

32. Negative Feedback Mechanism Analogy: a thermostat

33. Same diagram, but now featuring Regulation of Body Temperature

35. Biology, 9th ed, Sylvia Mader
Positive Feedback
Chapter 33
Animal Organization & Homeostasis
During positive feedback, an event increases the likelihood of another event occurring
Childbirth Process
Urge to urinate
Positive Feedback
Does not result in equilibrium; YES TO CHANGE
Does not occur as often as negative feedback