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3/23 Daily Catalyst Pg. 97 Homeostasis
1. Look at the following diagrams and predict in which direction osmosis will take place.
a) Use arrows to show the net direction of osmosis in each cell.
b) Describe what happens to each cell due to osmosis
c) Is one of these microbes an extreme halophile? Which one? How do you know?
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 2. Compare aerobic and anaerobic respiration with fermentation in general terms of
energy yield and final electron acceptors.
 3. What is the importance of waters high specific heat?
3/23 Daily Catalyst Pg. 97 Homeostasis
1. Look at the following diagrams and predict in which direction
osmosis will take place.
a) Use arrows to show the net direction of osmosis.
b) Describe what happens to each cell due to osmosis
c) Is one of these microbes an extreme halophile? Which one?
 Yes, the halophile is cell C because it is the highest concentration of
salt.
3/23 Daily Catalyst Pg. 97 Homeostasis
 2. Compare aerobic and anaerobic respiration with fermentation in
general terms of energy yield and final electron acceptors.
 Aerobic respiration yields 34-36 ATP molecules and the final
electron acceptor is O2. In Fermentation, only 2 ATP molecules are
made by Glycolysis and the final electron acceptors are ethanol
and lactic acid (NADH gives the electrons to the organic molecules
and NAD+ is regenerated)
 3. What is the importance of waters high specific heat?
 Waters high specific heat allows water to moderate temperature
and climate and
Brain Teaser
 What type of bow cannot be tied?
 A rain-bow!
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3/23 Daily Catalyst Pg. 97 Homeostasis
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Daily Catalyst
Class Business
Homeostasis notes
Video Clip
Vocabulary share out
Work Time
Essay prompt
Homework: read 41.3 and 41.4 (orange book)
41. 2 and 41.3 (purple book)
BODY SYSTEMS!
This unit is about different BODY
SYSTEMS….
3/23 Objective
Explain how body systems
maintain homeostasis
Examples of homeostasis…
Good blood sugar
Reacting to a hot stove
Good body fluid level
Sweating to maintain temp.
Ability to reproduce
Urinating to maintain pH
Homeostasis
 Key Point #1: Homeostasis is maintaining a stable
and internal environment.
What happens when our
body looks like this?
 How does the body maintain homeostasis?
 It take the cooperation of cells, tissues, organs, and
organ systems to ensure the body runs efficiently.
 Let’s start there
Chapter 40
Basic Principles of Animal Form and Function
Overview: Diverse Forms, Common
Challenges
 Animals inhabit almost every part of the biosphere
 Despite their amazing diversity
 All animals face a similar set of problems, including how to obtain
oxygen, nourish themselves, excrete waste products and move.
 How do animals of diverse evolutionary background solves
these unique problems?
 Keep in mind natural selection and adaptation
The comparative study of animals
reveals that form and function are closely
correlated
 Natural selection can fit anatomy to physiology
 By selecting, over many generations, what works best among the
available variations in a population
 KP #2:
 Anatomy: study of the structure
 Physiology: study of the functions
Physical Laws and the environment
constrain animal size and shape
 What determines the body plan of an animal?
 The animal’s genome (DNA!)
 Are the possibilities of body plans infinite?
 Nope! Only the body shapes that survive will preserve
Convergent Evolution

Reflects different species’ independent adaptation
to a similar environmental challenge
(a) Tuna
(b) Shark
(c) Penguin
(d) Dolphin
(e) Seal
The environment
 Key Point #3:
 All living cells exist in an aqueous environment
 Why? exchange with the environment.
 Exchange?
 Across a plasma membrane so fluid is essential
 Active and passive transport
 To maintain homeostasis!
External environment
Mouth
Food
CO2
O2
Respiratory
system
0.5 cm
Cells
Heart
Nutrients
Circulatory
system
A microscopic view of the lung reveals
that it is much more spongelike than
balloonlike. This construction provides
an expansive wet surface for gas
exchange with the environment (SEM).
10 µm
Interstitial
fluid
Digestive
system
Excretory
system
The lining of the small intestine, a digestive organ, is elaborated with fingerlike
projections that expand the surface area
for nutrient absorption (cross-section, SEM).
Anus
Unabsorbed
matter (feces)
Figure 40.4
50 µm
Animal
body
Metabolic waste
products (urine)
Inside a kidney is a mass of microscopic
tubules that exhange chemicals with
blood flowing through a web of tiny
vessels called capillaries (SEM).
Let’s talk organization
 We already know that Biologists love to
classify everything.
 We also love to organize everything too.
 Our body is no exception.
Key Point #4: Organization
ELLS
 C________
 Each cell has a special job for a specific task
ISSUES
 T________
 Similar cells that work together to perform a function
RGANS
 O_________
 Different types of tissues that function together
 O ________________
RGAN SYSTEMS
 Two or more organs working together in a system
RGANISM
 O____________
 The organ systems make up US!
Concept 40.2: Animal form and function are
correlated at all levels of organization
 Animals are composed of cells
 Groups of cells with a common structure and function
 Make up tissues
 Different tissues make up organs
 Which together make up organ systems
Tissue Structure and Function
 Different types of tissues
 Have different structures that are suited to their functions
 Key Point #5: Tissue types:
 Epithelial, connective, muscle, and nervous
Epithelial Tissue
 Key Point #6: Epithelial tissue
 Covers the outside of the body and lines organs and cavities
within the body
 Contains cells that are closely joined (lining)
EPITHELIAL TISSUE
Columnar epithelia, which have cells with relatively large cytoplasmic volumes, are often
located where secretion or active absorption of substances is an important function.
 Epithelial tissue
A simple
columnar
epithelium
A stratified columnar
epithelium
A pseudostratified
ciliated columnar
epithelium
Stratified squamous epithelia
Cuboidal epithelia
Simple squamous epithelia
Basement membrane
40 µm
Connective Tissue
 Key Point #7: Connective tissue
 Functions mainly to bind and support other tissues
 Contains sparsely packed cells scattered throughout an
extracellular matrix
 Connective tissue
CONNECTIVE TISSUE
100 µm
Chondrocytes
Chondroitin
sulfate
100 µm
Collagenous
fiber
Elastic
fiber
Cartilage
Loose connective tissue
Adipose tissue
Fibrous connective tissue
Fat droplets
150 µm
Nuclei
30 µm
Blood
Bone
Central
canal
Red blood cells
White blood cell
Osteon
Figure 40.5
700 µm
Plasma
55 µm
Muscle Tissue
 Key Point #8: Muscle tissue
 Long cells called muscle fibers capable of contracting in
response to nerve signals
 Divided in the vertebrate body into three types: skeletal,
cardiac, and smooth
Muscle cell types
Nervous Tissue
 Key Point #9: Nervous tissue
 Senses stimuli and transmits signals throughout the animal
 Limited life span
 Muscle and nervous tissue
MUSCLE TISSUE
100 µm
Skeletal muscle
Multiple
nuclei
Muscle fiber
Sarcomere
Cardiac muscle
Nucleus Intercalated
disk
Smooth muscle
50 µm
Nucleus
Muscle
fibers
25 µm
NERVOUS TISSUE
Process
Neurons
Cell body
Nucleus
50 µm
Organs and Organ Systems
 In all but the simplest animals
 Different tissues are organized into organs and organs are
organized into organ systems.
 Organ systems in mammals
Concept 40.4: Animals regulate their internal
environment within relatively narrow limits
 Key Point #10:
 The control center:
 the brain
 Once changes are detected, messages
are sent out to “fix” the changes.
Let’s Take it a step further…
 How does a thermostat work?
 A sensor in the thermostat continuously
measures the air temperature. A control
mechanism then compares the current
room temperature to a set point, say 70
degrees Fahrenheit.
 When the temperature falls below 70
degrees, the thermostat sends a message
that turns on the furnace.
 When the room temperature is above 70
degrees, the furnace will turn off.
3/24 Class Business
 Quiz #25 on Friday
 Parent Teacher Conference TONIGHT
 4-6 in the cafeteria
 Midterm e.c.
3/24 Agenda
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Daily Catalyst
Class Business
Finish homeostasis notes
Video clip on thermoregulation
Thermoregulation work time
Positive feedback example
Thermoregulation essay prompt
Homework: read about blood clots and diabetes and what
happens when feedback loops DO NOT work properly.
3/24 Objective
 We will be able to connect how organisms use
negative feedback to maintain their internal
environment.
 We will be able to justify that positive feedback
mechanisms amplify responses in organisms.
 Key Point #11: Most homeostatic control systems function by
negative feedback loops
 Where buildup of the end product of the system shuts the system
off
 Think back to enzymes!
Negative Feedback Loop
In the human body…
 This is the reason why you cannot hold
your breathe for a long time. As you hold
your breath, sensors in the circulatory and
respiratory system send information to the
BRAIN. The brain detects high levels of
CO2 and low levels of O2. This is not right!
The brain signals your LUNGS and
diaphragm to relax and take in a lot of
oxygen. You continue to breathe until the
O2 levels return to normal.
 Key Point #12: A second type of homeostatic control system is
Positive feedback
 Which involves a change in some variable that triggers
mechanisms that amplify the change
Living Things Use Feedback Mechanisms To
Maintain Homeostasis
Negative Feedback
 Stimulus
 Response shuts off
stimulus
Positive Feedback
 Stimulus
 Response increases
stimulus
 Bigger stimulus
 Bigger response
Negative Feedback
 More common
mechanism for
maintaining
homeostasis
 i.e. blood is acidic,
buffers neutralize it
Positive Feedback
 Increases intensity
 When a more intense reaction needed to get back to
homeostasis
 E.g. birth
 Concept 40.5: Thermoregulation contributes to homeostasis
and involves anatomy, physiology, and behavior
 Key Point #13: Thermoregulation
 Is the process by which animals maintain an internal temperature
within a tolerable range
Video clip
 http://www.bozemanscience.com/thermoregulation
How you might be tested on
this…
 Reptiles regulate their body temperature by changing
their environment. A snake for instance, must lie in
sunlight to warm its body. Mammals, on the other hand,
can regulate their internal environment to gain or lose
heat. How might this ability give mammals an
advantage over reptiles?
 Thermoregulation: the process of the body
maintaining its internal temperature.
Key Point #14:
 Endothermic: organism can regulate its own body
temperature
 Mammals
 Energy expensive
 Benefits?
 Exothermic: organism relies on the environment to
regulate their body temperature
 Reptiles and fish
 Energy inexpensive
 Downside?
Work Time
 1. Discuss how each of the following are involved in thermoregulation:
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fur/feathers
adipose tissue
goose bumps
vasodilation/vasoconstriction
panting/sweating
burrowing/sunning
 2. What are the evolutionary advantages of torpor and hibernation?
 3. What is the role of the hypothalamus in temperature regulation?
 4. The example in the text is related to temperature regulation. Would
ectotherms be regulators or conformers?
 5. If a mouse and a small lizard of the same mass (both at rest) were
placed in experimental chambers under identical environmental
conditions, which animal would consume oxygen at a higher rate?
Explain.
Question
 Reptiles are ectotherms and connot self regulate their
internal body temperatures. Because of this, many reptiles
must move around to find warm or cool areas. Dan the
reptile has just woken up and is freezing, even though hes
pretty fat. How could he become warm again?
A: The hypothalamus sends impulses to his sweat glands.
B: The hypothalamus sends impulses to his muscles to make
him shiver
C: He gets up and walks to a rock in sunlight
D: He knits himself a sweater
Essay Prompt
Answer key