BIOL 319 COHN EXAM 2 QUESTIONS
AND ANSWERS GRADED A+ 2025/2026
Physiology
scientific study of the function of the body
- molecular
- cellular
- tissue
- organ
- organ system
- organism
homeostasis
tendency to maintain a balanced internal state
- many physiological variables must be kept within well-defined limits enforced by physiological
control systems
- ex:
-- ph of blood (~ 7.4)
-- body temperature (~ 98.6 = 37 *C)
-- blood glucose
-- blood gases
-- blood pressure (120/80)
what organ systems maintain homeostasis
nervous
- brain and spinal cord
- speed of control VERY VERY quick
1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
,endocrine
- composed of endocrine glands that produce hormones that are put into blood --> finds and
binds to receptor protein
- speed of control much SLOWER than NS (takes a couple of seconds)
- takes care of reproduction and growth
thermoregulation
process of maintaining body temperature
- must occur very fast
electrolytes
aqueous ions - ions dissolved in water
- regulated inside and outside of a cell
- ex: sodium concentration inside and outside a cell
electrolytes regulated at constant levels
calcium - Ca++
- divalent cation
sodium - Na+
- monovalent cation
chloride - Cl-
phosphate - PO4^-3
- molecular ion
potassium - K+
bicarbonate - HCO3-
- CO2 + H2O = H2CO = H+ + HCO3
magnesium - Mg++
sulfate - SO4^-2
negative feedback
controls levels within a very narrow range (makes signal go to 0)
- output (signal= difference between ideal value and what the value is at) from the system
diminishes the value of the variable back toward the set point
signal/ deviation is ALWAYS
positive
set point
ideal value in the middle of the range of values
4 components of negative feedback
2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
, 1. signal (change in variable)
2. receptor (specific for 1 thing, in intimate contact with controller)
3. controller ("brains" receives 1 type of info and remembers set point) (makes decision of how
to change variable & sends command to effector)
4. effector ("muscle" lessens signal to 0)
circadian rhythm body temp
body naturally fluctuates temperature throughout the day
- lower in morning
- higher in evening
thermometer of body
temperature sensitive nerve endings (receptor)
thermostat/controller of body
hypothalamus
- temp control
- memorized 98.6
air conditioning of body
integumentary and cardiovascular system
- evaporative cooling - sweat glands pump sweat from body of gland, through duct, onto surface
of skin
- radiative cooling - sphincter muscles relax and diameter of lumen expand allowing more flow
of blood to the skin
heater in body
sphincter muscles contract and less blood goes into skin, retaining more heat
skeletal muscles shiver
can set points change
yes
- ex: blood pressure - during exercise demands of muscle increase, after exercise set point
readjusts
factors effecting bone growth
size and shape of a bone are determined genetically (like height- polygenic) but also can be
modified and influenced by nutrition and hormones
nutrition
lack of protein (collagen), calcium, phosphate, and other nutrients during growth and
development can cause bones to be small
- also negative effects of stress
3 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
AND ANSWERS GRADED A+ 2025/2026
Physiology
scientific study of the function of the body
- molecular
- cellular
- tissue
- organ
- organ system
- organism
homeostasis
tendency to maintain a balanced internal state
- many physiological variables must be kept within well-defined limits enforced by physiological
control systems
- ex:
-- ph of blood (~ 7.4)
-- body temperature (~ 98.6 = 37 *C)
-- blood glucose
-- blood gases
-- blood pressure (120/80)
what organ systems maintain homeostasis
nervous
- brain and spinal cord
- speed of control VERY VERY quick
1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
,endocrine
- composed of endocrine glands that produce hormones that are put into blood --> finds and
binds to receptor protein
- speed of control much SLOWER than NS (takes a couple of seconds)
- takes care of reproduction and growth
thermoregulation
process of maintaining body temperature
- must occur very fast
electrolytes
aqueous ions - ions dissolved in water
- regulated inside and outside of a cell
- ex: sodium concentration inside and outside a cell
electrolytes regulated at constant levels
calcium - Ca++
- divalent cation
sodium - Na+
- monovalent cation
chloride - Cl-
phosphate - PO4^-3
- molecular ion
potassium - K+
bicarbonate - HCO3-
- CO2 + H2O = H2CO = H+ + HCO3
magnesium - Mg++
sulfate - SO4^-2
negative feedback
controls levels within a very narrow range (makes signal go to 0)
- output (signal= difference between ideal value and what the value is at) from the system
diminishes the value of the variable back toward the set point
signal/ deviation is ALWAYS
positive
set point
ideal value in the middle of the range of values
4 components of negative feedback
2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
, 1. signal (change in variable)
2. receptor (specific for 1 thing, in intimate contact with controller)
3. controller ("brains" receives 1 type of info and remembers set point) (makes decision of how
to change variable & sends command to effector)
4. effector ("muscle" lessens signal to 0)
circadian rhythm body temp
body naturally fluctuates temperature throughout the day
- lower in morning
- higher in evening
thermometer of body
temperature sensitive nerve endings (receptor)
thermostat/controller of body
hypothalamus
- temp control
- memorized 98.6
air conditioning of body
integumentary and cardiovascular system
- evaporative cooling - sweat glands pump sweat from body of gland, through duct, onto surface
of skin
- radiative cooling - sphincter muscles relax and diameter of lumen expand allowing more flow
of blood to the skin
heater in body
sphincter muscles contract and less blood goes into skin, retaining more heat
skeletal muscles shiver
can set points change
yes
- ex: blood pressure - during exercise demands of muscle increase, after exercise set point
readjusts
factors effecting bone growth
size and shape of a bone are determined genetically (like height- polygenic) but also can be
modified and influenced by nutrition and hormones
nutrition
lack of protein (collagen), calcium, phosphate, and other nutrients during growth and
development can cause bones to be small
- also negative effects of stress
3 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
