Themes 4 + 5 Flashcards
Homeostasis and Environmental Adaptation & The Nervous System
Who defined homeostasis? (2 ppl)
Claude Bernard, Walter Cannon
Homeostasis
Process of maintaining a relatively stable internal environment despite changes in the external surroundings.
2 types of Homeostatis
Conformers and Regulators
Conformers
maintain same fluid composition as environment
Which is energetically cheaper? Conformers or Regulators?
Conformers
Regulators
internal composition of fluids different from environment
Thermogenesis
Generation of thermal energy in an organism
4 types of Thermogenesis?
Homeotherms
Poikilotherms
Endotherms
Ectotherms
Homeotherms
organisms that maintain a stable internal body temperature regardless of external influence.
Poikilotherm
organisms whose internal temperature varies considerably.
Which type(s) of Thermogenesis depends on ambient temperature?
Poikilotherm, Ectotherm
Endotherms
heat primarily generated from internal metabolic processes
Ectotherms
control body temperature through external means;
Example of an Ectotherm?
Reptiles; regulate body temperature by basking in the sun.
Can Poikilotherms be Ectotherms?
Yes, meaning their temperature varies over a wider range than homeotherms.
Are physiological functions constant for very long?
No
After a meal the level of glucose in your blood can…
increase rapidly
If you skip a meal, your blood sugar level may…
drop slightly.
4 Variables of Homeostatic Control Systems:
Set point
Sensor
Integrator
Effector
Set Point
normal value for controlled variable
Sensor
monitors particular variable
Integrator
compares signals from the sensor to set point
Effector
compensates for deviations between actual value and set point.
Feedback
a fundamental feature of homeostasis; major way disturbances are minimized.
Negative Feedback
variable being regulated bring about response that moves the variable in the opposite direction.
Positive Feedback
Accelerates a process;
Explosive system (rapid)
used in Birth + effect of estrogens in ovulation.
Where does negative feedback occur?
organ
cellular
molecular levels
What type of Feedback prevents overcompensation?
negative feedback
Another name for Positive feedback?
Supra-physiological responses
Feedforward Regulation
Animal’s body begins preparing for a change in some variable before it occurs.
Speeds up homeostatic responses and minimizes derivation from the set point.
What type of regulation is a result from or is modified by learning?
Feedforward Regulation
What type of Regulation is Anticipatory?
Feedforward Regulation
Pavlov ‘s experiment demonstrated the relationship between what 2 things?
Learning and Feedforward Processes
What chemical communication between cells is essential to homeostasis? (3)
paracrine signals
neurotransmitters
hormones
The Nervous system
a network of specialed cell that coordinate functions and transmit signals between different organs.
What System regulates internal processes-all while maintaining homeostasis?
The nervous system
2 Parts of the Nervous system?
Central Nervous System (CNS)
Peripheral Nervous System (PNS)
Central Nervous System organs?
Brain and spinal cord
Peripheral nervous system is composed of ?
all neurons and projections of their plasma membranes that are outside of the CNS.
T or F - In Certain invertebrates with a simple nervous system, the distinction between CNS and PNS is less clear or not present.
True
Composition of the CNS? (matters)
Grey Matter and White Matter
Grey Matter
is the major component of the CNS
What does Grey Matter consist of ?
Neuronal Cell bodies, dendrites, and axons
Glial cells
Capillaries
the grey-brown color in Grey matter comes from what?
Capillary blood vessels and neuronal cell bodies.
White matter
mostly contains myelinated axon tracts
What does the white color in White matter come from?
whiteness of myelin.
Myelin
an electrically insulating material that forms a layer around axons.
What is Myelin composed of?
80% lipids(primarily glycolipids galactocerebroside)
20% protein