Homeostasis (Unit 4) chapter 9 Flashcards
refers to the body’s attempt to adjust to the fluctuating external environment
Homeostasis
In other words the body tries to maintain a stable ______ environment.
internal
There are many different systems all working together within the body to maintain its _______
internal balance
Refers to extracellular fluid, which
consists of interstitial fluid (between cells and tissue) and blood plasma
The Internal Environment
The volume, temperature, and chemical composition of our internal environment can change _____
quickly
Body uses ______ to regulate its internal conditions.
many systems
Organ Systems Involved in
Homeostasis
-nervous system
-endocrine system
-muscular system
-integumentary system
-excretory system
-reproductive system
how does body regulate body temp?
evaporation of water helps
hypothalamus regulates ____ and changes in ______
temperature and changes in osmotic pressure
kidneys maintain
water balance
pancreas regulates
blood sugar
Take in, process and distribute nutrients and other chemicals; also dispose of wastes
All organ systems
blood distributes _____ throughout the body
heat
skeletal muscles contract and release _____
heat
All organ systems synthesize nutrients and other molecules essential for __________
cellular function
organ systems Respond to ______ in environment
changes
Organ system Protects body from _____ and ______
injury
infection
organ systems:
Reproduce
Involve “detection” and “correction”
Homeostasis and Feedback
Mechanisms
Homeostasis and Feedback
Mechanisms: Both _____ and _____ feedback mechanisms
positive
negative
Primary mechanism of homeostasis
Negative Feedback
negative feedback stimulus triggers a response that
_______
compensates for the change
In the human body there are three main
components of homeostatic control
- Sensor (eg sensory neuron)
- Integrator (eg the brain)
- Effector (a muscle or gland)
Integrator activates ______
effector
_____ gathers information and sends to the _____
Sensor
integrator
The integrator compares to set points (______________________)
optimal functioning conditions
Negative Feedback Mechanisms
in Animals (Diagram explained)
Examples of + feedback include __________
Child Birth and Ejaculation
Therefore the variable is moved _______ from the steady state.
farther away
_______ is a system which reinforces changes which are occurring
Positive Feedback
_______ is the maintenance of body temperatures within a range that enables cells to function properly
Thermoregulation
Optimal Internal Temperature ______ from species
to species.
differs
Human:
37oC
Animals absorb energy if they are _____ than their external environment and
release thermal energy if they are ______ than their environment
cooler
warmer
Energy exchange can occur through:
conduction, convection, radiation, and evaporation
These terms describe what happens to an organism’s internal temperature
Homeotherms and Poikilotherms
maintain a stable body
temperature regardless of the
environment
Homeotherms
body temperature varies
with the environment
Poikilotherms
maintain a constant* internal temperature by generating heat through an increase in cellular respiration
Endotherm
use external (environmental) mechanisms to control their temperature (ex. Fish, Reptiles, Insects etc.)
Ectotherm
Therefore:
Most endotherms are _______
Most ectotherms are ________
homeotherms
poikilotherms
So how do humans stay
warm/cool?
homeostasis diagram
As water freezes it forms
_______ which
rupture cell walls
sharp ice crystals
Water also expands
when frozen and when
this occurs in an
organism it can:
destroy many important body tissues
So how do wood frogs survive being frozen?
They produce antifreeze within cells to prevent freezing
(Glucose)
They also dehydrate cells to prevent ice from forming
daily/nightly periods of decreased
physiological activity resulting in lowered metabolism and temps to conserve energy
Torpor
eg. of torpor
Some birds, marsupials, mammals such as rodents and bats
torpor occurring over an extended period (weeks/months) during winter
Hibernation
torpor occurring over an extended
period during summer
Estivation
results from difference in solute concentration on two sides of membrane
Osmotic pressure
actively regulating water balance/osmotic pressure of bodily fluids and cells
Osmoregulation
Excretion: Certain _______, ______ and ______ compounds must
be eliminated
ions, toxins and nitrogenous
_____ needed for terrestrial
organisms to dissolve solutes
and then excrete
Water
What is regulted in Excretion
Ionic and pH balance and
osmotic concentration