What things to animals do to maintain homeostasis?
1
Lecture 9 Outline (Ch. 40)
I.
Brief Organ Systems Overview
II.
Animal Size/Shape and the Environment
III. Tissues
A.
Epithelial
B.
Connective
C.
Muscle
D.
Nervous
IV. Feedback Control and Heat Balance
V.
Metabolic Rate and Energy Use
VI. Preparation for next lecture
2
Overview: Diverse Forms, Common Challenges
• Anatomy: study of biological form of an organism
• Physiology: study of biological functions of an organism
• Evolutionary convergence:
reflects different species’
adaptations to similar
environmental challenge
(a) Tuna
(b) Penguin
3
(c) Seal
Organ Systems
• Communication and integration
– detect external stimuli, coordinate the body’s responses
• Support and movement
4
Organ Systems
• Regulation and maintenance
– regulate and maintain the body’s chemistry
5
Organ Systems
• Defense
• Reproduction and development
– In females, also nurtures developing embryo/fetus
6
Hierarchical Organization of Body Plans
• Vertebrates have a “tube within a tube” structure
• Levels or organiziation: smallest  largest?
7
Overview: Diverse Forms, Common Challenges
Rate of exchange related to SA
Amount of exchange related to V
Mouth
Gastrovascular
cavity
Exchange
Exchange
Exchange
0.15 mm
1.5 mm
(a) Single cell
(b) Two layers of cells
8
Overview: Diverse Forms, Common Challenges
• More complex organisms have highly folded internal surfaces
Animal
body
Respiratory
system
0.5 cm
50 µm
Cells bathed in
interstitial fluid
External environment
CO2
Food
O2
Mouth
Lung tissue
Nutrients
Heart
Cells
Circulatory
system
10 µm
Interstitial
fluid
Digestive
system
Excretory
system
Lining of small intestine
Kidney tubules
Anus
Unabsorbed
matter (feces)
Metabolic waste products
(nitrogenous waste)
9
Tissue Structure and Function
• Tissues are classified into four main categories:
epithelial, connective, muscle, and nervous
Humans: 210 different cell types – can you name them?! ;) 10
Tissue Structure and Function
Epithelial Tissue
Cuboidal
epithelium
Simple
columnar
epithelium
Pseudostratified
ciliated
columnar
epithelium
Stratified
squamous
epithelium
Simple
squamous
epithelium
Note differences in cell shape and type of layering
11
Tissue Structure and Function
Apical surface
Basal surface
Basal lamina
40 µm
Epithelial cells are attached to a basal lamina at their base.
12
Connective Tissue
• Connective tissue mainly binds and
supports other tissues
• It contains sparsely packed cells scattered
throughout an extracellular matrix
• The matrix consists of fibers in a liquid,
jellylike, or solid foundation
There are six main types of connective tissue.
13
Tissue Structure and Function
Connective Tissue
Loose
connective
tissue
Chondrocytes
Cartilage
Elastic fiber
Chondroitin
sulfate
Nuclei
Fat droplets
Adipose
tissue
Osteon
150 µm
Fibrous
connective
tissue
30 µm
100 µm
120 µm
Collagenous fiber
White blood cells
Blood
55 µm
700 µm
Bone
Central canal
Plasma
Red blood
cells
14
Muscle Tissue
• Muscle tissue consists of long cells called muscle fibers,
which contract in response to nerve signals
• It is divided in the vertebrate body into three types:
– Skeletal muscle, or striated muscle, is responsible for
voluntary movement
– Smooth muscle is responsible for involuntary body
activities
– Cardiac muscle is responsible for contraction of the
heart
15
Tissue Structure and Function
Muscle Tissue
Multiple
nuclei
Muscle fiber
Sarcomere
Skeletal
muscle
Nucleus
100 µm
Intercalated
disk
50 µm
Cardiac muscle
Nucleus
Smooth
muscle
Muscle
fibers
25 µm
16
Tissue Structure and Function
Nervous Tissue
• Nervous tissue senses stimuli and transmits signals 40 µm
throughout the animal
Dendrites
• Nervous tissue contains:
Neurons, or
nerve cells,
transmit
nerve
impulses
Glial cells, or
glia, help
nourish,
insulate, and
replenish
neurons
Cell body
Glial cells
Axon
Neuron
Axons
Blood vessel
17
15 µm
Which animals tissue below is connective?
1.
2.
3.
4.
5.
Cardiac cells
Glia
Lining of intestines
Tendons
Neurons
Self-Check
Tissue Category
Tissues/Cells Included; Functions
Epithelial
Connective
Muscle
Nervous
19
Feedback control loops maintain the internal
environment in many animals
Response:
Heater
turned
off
Room
temperature
decreases
Examples of negative
and positive feedback?
Stimulus:
Control center
(thermostat)
reads too hot
Set
point:
20ºC
Stimulus:
Control center
(thermostat)
reads too cold
Room
temperature
increases
Response:
Heater
turned
on
20
Feedback control loops maintain the internal
environment in many animals
• Animals manage
their internal
environment by
regulating or
conforming to the
external environment
Feedback control loops maintain the internal
environment in many animals
• Thermoregulation: process
by which animals maintain
an internal temperature
• Endothermic animals
generate heat by
metabolism (birds and
mammals)
• Ectothermic animals gain
heat from external sources
(invertebrates, fishes,
amphibians, and nonavian reptiles)
(a) A walrus, an endotherm
(b) A lizard, an ectotherm
22
Balancing Heat Loss and Gain
• Five general adaptations
help animals
thermoregulate:
– Insulation
– Circulatory adaptations
– Cooling by evaporative
heat loss
– Behavioral responses
– Adjusting metabolic heat
production
Dragonfly “obelisk” posture
23
Energy Allocation and Use
External
environment
• Bioenergetics:
overall flow of
energy in an animal
• Determines how
much food is
needed due to
animal’s size,
activity, and
environment
Animal
body
Organic molecules
in food
Digestion and
absorption
Heat
Energy lost
in feces
Nutrient molecules
in body cells
Carbon
skeletons
Cellular
respiration
Energy lost in
nitrogenous
waste
Heat
ATP
Biosynthesis
Cellular
work
Heat
24
Heat
Energy Use
• Metabolic rate is the amount of energy an animal uses in
a unit of time
Measured by
amount of
oxygen
consumed or
carbon dioxide
produced
• Basal metabolic rate (BMR) is the metabolic rate of an
endotherm at rest at a “comfortable” temperature
25
Energy Use
103
BMR (L O2/hr) (log scale)
Elephant
Horse
102
Human
Sheep
10
Cat
Dog
1
10–1
Rat
Ground squirrel
Shrew
Mouse
Harvest mouse
10–2
10–3
10–2
102
1
10–1
10
Body mass (kg) (log scale)
(a) Relationship of BMR to body size
103
26
Energy Use
8
Shrew
BMR (L O2/hr) (per kg)
7
Human average daily metabolic
rate is only 1.5X BMR!
6
5
4
Harvest mouse
3
Mouse
2
Rat
1
Ground squirrel
0
10–3
10–2
Sheep
Human Elephant
Cat
Dog
Horse
1
10
102
10–1
Body mass (kg) (log scale)
103
(b) Relationship of BMR per kilogram of body mass to body size
27
Energy Budgeting
Endotherms
Reproduction
800,000
Annual energy expenditure (kcal/hr)
Ectotherm
Basal
(standard)
metabolism
Thermoregulation
Growth
Activity
340,000
4,000
60-kg female human
from temperate climate
4-kg male Adélie penguin
from Antarctica (brooding)
0.025-kg female deer mouse
from temperate
North America
8,000
4-kg female eastern
indigo snake
• Torpor is a physiological state in which activity is low and
metabolism decreases – allows animals to save energy
while avoiding difficult and dangerous conditions
• Hibernation is long-term torpor that is an adaptation to
winter cold and food scarcity
28
Which animal would have the highest BMR
per unit body weight?
1.
2.
3.
4.
5.
human
dog
mouse
whale
turtle
Metabolic rate
(kcal per day)
Energy Use
200
Actual
metabolism
100
0
35
30
Temperature (°C)
Additional metabolism that would be
necessary to stay active in winter
Arousals
Body
temperature
25
20
15
10
5
0
–5
Outside
temperature
Burrow
temperature
–10
–15
June
August
October
December
February
April
30
Things To Do After Lecture 9…
Reading and Preparation:
1.
Re-read today’s lecture, highlight all vocabulary you do not
understand, and look up terms.
2.
Ch. 40 Self-Quiz: #1, 2, 3, 4, 5, 6 (correct answers in back of book)
3.
Read chapter 40, focus on material covered in lecture (terms,
concepts, and figures!)
4.
Skim next lecture.
“HOMEWORK” (NOT COLLECTED – but things to think about for studying):
1.
Describe the relationship between surface area and volume for a small
cell compared to a large cell. Which is more efficient at exchange with
the environment?
2.
List the four types of tissues in animals – for each one, give several
examples.
3.
Define basal metabolic rate. Which would use more energy for
homeostatic regulation, a human or a snake? Why?
4.
Explain the difference between torpor and hibernation.