Unit 4 - intro to homeostatis Flashcards
what is homeostasis
ability of an organism to maintain a stable internal environment, depsite changes to its interlan or external environment
homosis = similar
stasis = standig still
Internal Environment
the IE refers to the extercellular fluid which condsists of IF that fills the space between out cells and tissues and plasma or fluid portion of our blood
Homeostasis focuses in on…
the fluid outside the cell which act as a medium for delivering energy transporting chemical and eliminating waste
Organ systems involved in Homeostasis
1) nervous =
brain/ spinal cord
2) endocrine =
thyroid/adrenal gland
3) muscular =
skeletal / cardiac
4) integumentary =
skin / sweet / nails / hair
5) excretory =
kidney / bladder
6) reproductive =
testies / overies
internal environment
when cells function properly in the tissues and organ systems the whole organ can thrive
Temp, volume, chemical composition…
of internal environment can change quickly
rigorous physical activity, extreme conditions or infections
can tip the balance in the extracellular fluid
dramatic changes ( often -)
effecting cellular functions, so the body uses many systems to maintain and regulate its internal conditions
Normal body ranges (7)
body temp = 37c
bp = 120/80
blood pH = 7.3-7.5
o2 and co2 conc.
water balance
blood glucose = 0.1%
calcium levels = 8.5-10.5
Homeostasis and Feedback mechansms
Homeostasis is monitored through constant monitoring and feedback of body conditions. If conditions are outside of the optimal functioning range, the mechanisms take corrective action to bring the body back into balance.
How does homeostasis work = feedback pathways
- organs and structures communicate with each other in response to changes in the body
- Keeps levels of certain processes within a normal range
3 components
sensor
integrator
effector
Sensor; receptors
tissues or organs that detect any change—or stimuli
Gathers and transmits to Integrator
Integrator; brain
acts as a processor or control centre. compares the environmental conditions with the optimal functioning condition know as set point
environment outside of set point =
the integrator activates the effector
Effector; muscle and glands etc
returns that measured conditions to the desired set point know as the response
Positives vs. Negative Feedback
Negative Feedback: mechanism in homeostasis whereby the output reverses the variable bringing it back to a normal state of balance.
Positive Feedback: mechanism in homeostasis whereby the output strengthens and increases the change in the variable.
Negative Feedback
process by which a mechanism is activated to restore condionts to there orignal state
ie. small changes dont bc to big
- cellular materials
- energy
Negative Feedback ex
Thermostat in a house
top feedback loop
if room gets hotter then set point thermostat will detect change and turn on air conditioner to cool room and return to set point
bottom feedback loop
room gets colder then the set point the thermostat will detect the change and turn on the furnace in order to warm the room and return to the set point
Thermoregulation; core temp
- humans normal temp between 35 to 38.6c
above (hyperthermia)=
infection
below (hypothermia)=
cell death
Heat Stress; sensor
thermoreceptors of the peripheral nervous system detact an increase in body temp. send message via seneroy neurons to brain
Heat Stress; integrator
Hypothalamus (CNA) signlas via motor neruons to sweat glands
Heat Stress; Effector
sweat glands initiate sweating evaporating sweat off the skin = cooling
blood vesicles in the skin dilate allowing blood to flow to the skin and heat from blood is lost to the skin so blood can return to core temp
Result of heat stress
body temp returns to normal hypothalamus turns of cooling system
cooling glove
heat extractor increases heat loss and allows the body to perform a higher level in sever conditions
Cold Stress; Sensor
thermoreceptors message the hypothalamus using sensory neurons
Cold Stress; Integrator
hypothalamus send a message via motor neurons
Cold Stress; Effector
arterioles of the skin constrict therefore limiting blood flow and reducing heat loss from the skin
cold stress smooth muscles
that surrond the hair follicles in your skin contract causing hair to stand trapping warm air
cold stress skeletal muscles
contract causing shivering and increasin metabolism to make heat
result of cold stress
body temp increase and hypothalamus turns off heating system
blood sugar levels spike
beta cells in the pancrease will release insulin. Insulin is detected by cells and they begin to take up glucose and storing it as glycogen
blood sugar levels drop
alpha cells in plancreas release glucagon which signals cells to release glucose by breaking glycogen
Insulin
produced by b cells of the pancres
released into circ system when blood glucos is high
facilitates tranposrt of glucose into target cells
glucagon
make by a-cells of pancrease
released into circ system when blood glucose is low
signals the liver to break down glycogen into simple glucose
positive feedback
babies being born where oxytocin is released and strengthens the response of contractions + in milk glands oxytocin released during breastfeeding to increase the mothers milk supply.
