Physiology
Overview Vertebrates
Chapter 40
What you need to know
 The
four types of tissues and their general
functions
 The importance of homeostasis and
examples
 How feedback systems control
homeostasis and 1 example of positive
feedback and 1 example of negative
feedback
Organ Systems (On AP Test)
1.
2.
3.
4.
5.
Digestive System (nutrition/solid waste)
Endocrine System (regulation)
Respiratory System (gas exchange)
Circulatory System (transport)
Excretory System (homeostasis, liquid
waste)
Organ Systems
6.
7.
8.
9.
10.
11.
Integumentary System (Cartilage,
connective tissues)
Nervous System (integration of body and
environment through senses)
Muscular System (locomotion)
Lymphatic Immune System (defense)
Reproductive System
Skeletal System (bones)
Hierarchy
 Cells
 tissues  organs  organ systems
 Example:
 Neurons  nervous tissue  brain 
nervous system
Specialized Cells/Tissue
1.
Epithelial cells (endoderm & ectoderm):



2.
Cells that cover interior and exterior body
surfaces including glands
Skin, lining of lungs, and all other organs
Tight junctions
Connective Tissue (mesoderm):



Supports the body, and connects parts together
Connective, adipose, cartilage, bone, and
blood
Loose connections
Specialized Cells/Tissue
3.
Nervous tissue (ectoderm):


4.
Conducts impulses throughout the body
Nerve cells, brain cells, and spinal cord
Muscle tissue (mesoderm):


Actin/myosin cytoskeleton parts in
cytoplasm of muscle cells convert ATP into
movement
Skeletal muscles, smooth muscles, and
cardiac muscles
Metabolism
 ATP
production through cellular
respiration
 Metabolic rates in organisms determined
by ATP requirements for survival


High in endothermic
Low in exothermic (approx. 90% lower)
Homeostasis
 Dynamic
set of mechanisms that regulate
internal environment
Homeostasis – steady state
 All
organisms do homeostasis
 Isolation from environment is impossible for
survival
 External environment changes the internal
environment
 Wide fluctuations in external environment
 Stable internal environment promotes
healthy metabolism
Feedback Loops
 Regulate
1.
body functions
Receptor

2.
Control center


3.
detects change
receives info from the receptor and directs
response
Usually hypothalamus
Effector

Carries out response
Negative Feedback Loops
 Effectors
reduce change, preventing
small changes from becoming big
changes
 Most homeostatic mechanisms are
negative feedback loops: temp, blood
sugar, pH, hydration, and oxygen supply
Negative Feedback Example
Positive Feedback Loops
 Change
stimulates response that further
amplifies change (rare)
 Childbirth:


Stimulus: pressure of head on cervix
Response: increased contractions
Thermoregulation/Endotherms
 Source
of body heat = intense
metabolism
 Metabolism increases 2x every 100 Celsius
 Body temp is independent of environment

Mostly high temperatures that are narrowly
regulated
 High
food consumption
 Body surface area/volume ratio is
important
 Mammals and Birds
Variations of Thermoregulation
 Poikilotherms:
temperature


Marine fish tend to have body
temperatures higher than water due to high
metabolisms
Hibernation in some mammals
 Homeotherm:

large variation of body
Humans
stable body temperature
Heat Production/Conservation
 Insulation:
fur, feathers, blubber
 Acclimations: seasonal change of
winter/summer coat, and membrane
fluidity (regulated by fatty acids)
 Shivering: muscle contractions regulated
by hormones (adrenalin, thyroxin)

Insects shiver and/or rub their wings
Heat Regulation Mechanisms
 Counter


current exchange
temperature exchange between incoming
and outgoing blood flow
Bird feet, fish fins, marine mammal flippers
 Vasoconstriction:
smooth muscle nodes
around capillaries reduce blood flow to
extremities (conservation)
 Vasodilation: relaxation of smooth
muscles increases blood flow (radiation)
Heat Regulation Mechanisms
 Hibernation:
lowering of body temp and
activity level to save food stores
 Behaviors: avoiding/seeking heat, shade,
cool water
 Sweating: heat loss through evaporation
from skin
 Panting: heat loss through evaporation of
saliva
Heat Regulation Mechanisms
 Large
extremities: ears/tail for heat loss
 Small extremities: for heat retention
 Hypothalamus: Thermo-regulator in the
brain
Hypothalamus
 Nerve
cells in the hypothalamus can
detect if blood temperature is off
 Below set point: induction of shivering and
vasoconstriction of tissues in extremities
(raise/conserve core temperature)
 Above set point: induction (adrenalin and
glucagon) of sweating, panting, and
vasodilation (lower core temperature)
Endocrine System
 Produces
hormones that regulate
homeostasis, reproduction, and
development
 Characteristics of hormones include:
 Transported by blood
 Minute amounts required to stimulate
body wide response
 Are either steroids, peptides, or amino
acids