Western
Physiology 2130
FINAL EXAM
STUDY GUIDE
,
, find more resources at oneclass.com
Introduction to Physiology
INTRODUCTION
- Physiology = study of function in living organisms
o Mechanisms by which organisms control internal environments regardless of
what happens in the external environment
HOMEOSTASIS
- Internal environment= fluid in which cells of our body are bathed
o Interstitial fluid and blood plasma
- External environment = region outside the body
o Space and contents of the digestive, respiratory and urogenital tracts
- Homeostasis: maintenance of relatively stable conditions within the internal
environment regardless of what is happening in the external environment
o Body maintains homeostasis by using neg. and pos. feedback control
mechanisms
o Ex. Maintaining constant body temperature, water balance, salt concentrations,
etc.
NEGATIVE FEEDBACK CONTROL SYSTEMS
- Contain a set point, a control center (integrator), an
effector, controlled variable, sensor (receptor)
- Ex. Heating system in house
o Set point = temperature the room is set
o Sensor / control center = thermostat
o Effector = furnace
o Controlled variable = heat
o
- Called a negative feedback system because the controlled variable eventually shuts off
its own production by the effector
Watch video
- This also controls body temperature
o Set point = body temperature @ 37C (temp you want your body to maintain)
o The actual body temperature is detected by sensors in the nervous system which
would signal a control center in the hypothalamus
Notices a difference between set point and actual value and activates
organs and systems (effector) to generate heat (controlled variable) by
shivering and conserving heat by dec. blood flow to skin
o Once body temp rises back to normal, the control center would stop the
shivering and would return the blood flow to the extremities
find more resources at oneclass.com
, find more resources at oneclass.com
o IF body temp inc, sensors detect the rise and signal the hypothalamus signals
blood vessels in the skin to dilate and sweat glands to sweat heat dissipates
and body temp drop to normal
POSITIVE FEEDBACK CONTROL SYSTEMS
- Controlled variable stimulates its own production
- Self-amplifying mechanisms that can produce
rapid change
- Controlled variable is detected by the sensor
that signals the control center to activate the
effector to produce more of the controlled
variable
o Large amounts of the controlled
variable are produced rapidly
NEGATIVE AND POSITIVE FEEDBACK CONTROL SYSTEMS
- These two systems rely on 2 control systems to function properly
o Nervous system
Brain, spinal cord, nerves
Adapted for rapid communication through its complex system of neurons
and nerves
o Endocrine system
Replies more slowly, communicating by the release & distribution of
hormones in the blood
THE BODY’S STRUCTURAL HEIRARCHY
- Molecules macromolecules cellular organelles
- Some cells have taken the basic structures and turned them into highly specialized
structures
o Specialized structures give each cell in the body a specific purpose
find more resources at oneclass.com
Physiology 2130
FINAL EXAM
STUDY GUIDE
,
, find more resources at oneclass.com
Introduction to Physiology
INTRODUCTION
- Physiology = study of function in living organisms
o Mechanisms by which organisms control internal environments regardless of
what happens in the external environment
HOMEOSTASIS
- Internal environment= fluid in which cells of our body are bathed
o Interstitial fluid and blood plasma
- External environment = region outside the body
o Space and contents of the digestive, respiratory and urogenital tracts
- Homeostasis: maintenance of relatively stable conditions within the internal
environment regardless of what is happening in the external environment
o Body maintains homeostasis by using neg. and pos. feedback control
mechanisms
o Ex. Maintaining constant body temperature, water balance, salt concentrations,
etc.
NEGATIVE FEEDBACK CONTROL SYSTEMS
- Contain a set point, a control center (integrator), an
effector, controlled variable, sensor (receptor)
- Ex. Heating system in house
o Set point = temperature the room is set
o Sensor / control center = thermostat
o Effector = furnace
o Controlled variable = heat
o
- Called a negative feedback system because the controlled variable eventually shuts off
its own production by the effector
Watch video
- This also controls body temperature
o Set point = body temperature @ 37C (temp you want your body to maintain)
o The actual body temperature is detected by sensors in the nervous system which
would signal a control center in the hypothalamus
Notices a difference between set point and actual value and activates
organs and systems (effector) to generate heat (controlled variable) by
shivering and conserving heat by dec. blood flow to skin
o Once body temp rises back to normal, the control center would stop the
shivering and would return the blood flow to the extremities
find more resources at oneclass.com
, find more resources at oneclass.com
o IF body temp inc, sensors detect the rise and signal the hypothalamus signals
blood vessels in the skin to dilate and sweat glands to sweat heat dissipates
and body temp drop to normal
POSITIVE FEEDBACK CONTROL SYSTEMS
- Controlled variable stimulates its own production
- Self-amplifying mechanisms that can produce
rapid change
- Controlled variable is detected by the sensor
that signals the control center to activate the
effector to produce more of the controlled
variable
o Large amounts of the controlled
variable are produced rapidly
NEGATIVE AND POSITIVE FEEDBACK CONTROL SYSTEMS
- These two systems rely on 2 control systems to function properly
o Nervous system
Brain, spinal cord, nerves
Adapted for rapid communication through its complex system of neurons
and nerves
o Endocrine system
Replies more slowly, communicating by the release & distribution of
hormones in the blood
THE BODY’S STRUCTURAL HEIRARCHY
- Molecules macromolecules cellular organelles
- Some cells have taken the basic structures and turned them into highly specialized
structures
o Specialized structures give each cell in the body a specific purpose
find more resources at oneclass.com
