activities part 1 Flashcards
what is homeostasis
the state of steady internal, physical, and chemical conditions maintained by living systems
negative feedback
it negates an initial change, if theres a change away from a set point, that change is negated returning the organism to the set point
example of negative feedback
blood sugar, if blood sugar gets too high, pancreas will release insulin which lowers sugar so that it goes back to set point, the change was negated
positive feedback
more rare, it amplifies an initial change
example of positive feedback
milk ejection reflex, initial condition is that no milk is released, when baby sucks, receptors release oxytocin to cause more milk to flow
what does the respiratory of birds have
lungs and air sacs
what is responsible for gas exchange in bird
lungs
what do the birds air sacs do
they allow air to flow unidirectionally
the bird sacs has both
anterior and posterior air sacs
what occurs during inhalation
the air sacs expand draw air from the environment into the posterior air sac. the air in the lungs are drawn into the anterior air sacs.
what occurs during exhalation
the air sacs compress pushing the air from the posterior air sac into the lungs and the air in the anterior sacs out through the trachea
what occurs after a second full breath
air in the respiratory system completes the cycle, it leaves the lungs passes through the anterior air sacs an exits the body
how does the respiratory system of bird differ from mammals
mammals have a bi directional air flow.
how is the respiratory system of bird advantageous
the unidirectional system is so efficient birds can sustain activity at high altitudes
unidirectional flow optimizes what
pressure difference
what kind of air is located in the anterior air sacs
deoxygenated
artery
moves blood away from the heart (oxygenated blood)
the artery has what structures
endothelium, connective tissue, smooth muscle, and elastic tissue
endothelium
inner lining of blood vessels and is continuous with endothelium of heart
connective tissue
fibrous connective tissue helps prevent tearing of the blood vessel walls
arteries hold what kind of pressure
high pressure
smooth muscle
makes arteries and arterioles have variable diameter of vessels, when diameter changes, blood flow changes
elastic tissue
allow arteries to withstand high pressures
veins
take deoxygenated blood back to heart, has low blood pressure
veins have what structures
smooth muscle, connective tissue, valves, endothelium
veins do not have
elastic tissue
what are the components of circulatory system
fluid, pump, and conduits
valves
some veins have valves to stop backflow of blood
homeostasis
stability of the internal environment of an individual such as constant body temp and the physiological or behavioral feedback responses that maintain that stability
thermoregulation
animals that maintain a constant internal body temp
what does the body do when external temp goes over or under the thermoneutral zone
the metabolic rate increases to try and get the body back to set point
ectotherm
animals that permit their body temp to match external temp (frogs, crayfish etc)
what kind of metabolic rate do ectotherms have? endotherms?
ecto: low metabolic rate/low oxygen demand endo: high metabolic rate/high oxygen demand
ectotherms exhibit what kind of behavior
behavioral thermoregulation so if it gets too hot, they go into the shade
what is a control system
organs or cells that can sense when conditions deviate from the norm and can initiate physiological mechanisms in response
what are the four essential elements of a control system
- controlled variable 2. sensors 3. effectors 4. control mechanisms
controlled variable
the characteristic of an animal that is being controlled (ex. temp)
sensors
they detect the current level of the controlled variable (ex. skin or brain)
effectors
tissues or organs that can alter the level of the controlled variable (ex. shivering muscles)
control mechanism
used the info from the sensors to determine which effector to activate and how intense
what kind of feedback is temp
negative
insects have what kind of circulatory system
they have tracheal branching where 02 is brought to every cell in the body by a branch of the breathing system, NOT blood circulation
since insects have a very simple respiratory system, what does that mean about their metabolic rate
low performance so low metabolic rate
closed circulatory system
where the circulatory fluid is contained within a continuous system of vessels
open circulatory system
where the blood leaves blood vessels and travels through spaces bounded by ordinary tissue cells as it flows through the body
what is an effect of mammals and birds high metabolic rate mean about their circulatory system
they need a system more complex that will deliver 02 faster
arteries
moves oxygenated blood away from heart, high pressure
veins
moves deoxygenated blood towards the heart, low pressure
vasodilation
lumen (hole) of arteriole is large in diameter and blood flows fast
vasoconstriction
the arteriole diameter gets smaller causing less blood to travel
what is a key feature of a open circulatory system
there is no distinction between blood (fluid pumped by the heart) and the interstitial fluid (fluid in between cells)
what is blood and interstitial fluid mixed called
hemolymph
respiratory pigment
proteins that are present in the blood and that greatly increase the amount of 02
what is the respiratory pigment of humans
hemoglobin
