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 change

2. Control center receives info from the receptor and

directs response Usually hypothalamus

3. 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