Post on 24-Feb-2016
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Physiology Overview - VertebratesChapter 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. Digestive System (nutrition/solid
waste)2. Endocrine System (regulation)3. Respiratory System (gas exchange)4. Circulatory System (transport)5. Excretory System (homeostasis, liquid
waste)
Organ Systems6. Integumentary System (Cartilage,
connective tissues)7. Nervous System (integration of body
and environment through senses)8. Muscular System (locomotion)9. Lymphatic Immune System (defense)10. Reproductive System11. Skeletal System (bones)
Hierarchy Cells tissues organs organ systems Example: Neurons nervous tissue brain
nervous system
Specialized Cells/Tissue1. Epithelial cells (endoderm & ectoderm):
Cells that cover interior and exterior body surfaces including glands
Skin, lining of lungs, and all other organs Tight junctions
2. Connective Tissue (mesoderm): Supports the body, and connects parts together Connective, adipose, cartilage, bone, and blood Loose connections
Specialized Cells/Tissue3. Nervous tissue (ectoderm):
Conducts impulses throughout the body Nerve cells, brain cells, and spinal cord
4. 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 body functions1. Receptor
detects change2. Control center
receives info from the receptor and directs response
Usually hypothalamus3. 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: large variation of body
temperature Marine fish tend to have body
temperatures higher than water due to high metabolisms
Hibernation in some mammals Homeotherm: stable body temperature
Humans
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