Homeostasis Flashcards
What is homeostasis?
An essential regulatory process to maintain optimal conditions within the body
What are the two systems that communicate in homeostasis?
Nervous system and endocrine system
What is the nervous system?
An interconnection of nerves carrying electrical signals all over the body
What is the endocrine system?
A system where hormones carry signals all over the body
What is the central nervous system?
Where all the information is processed
What is the central nervous system composed of?
The brain and spinal cord
What are sensory nerves?
Receptors and afferent neurons
What are motor nerves?
Efferent neurons exciting effector organs
What are afferent neurons?
Neurons which are AFFECTED by something
What are efferent neurons?
Neurons which EFFECT something to do something
What is the autonomic nervous system?
Nervous system which controls things without thought such as heartbeat, breathing, digestion etc
What is the somatic nervous system?
Nervous system which control voluntary movement
How are hormones carried to all parts of the body?
Through the blood in the plasma
How are hormones carried locally?
Through interstitial fluid
What is the main role of the hypothalamus?
It is the link between the nervous system and the endocrine system
What is the neuroendocrine system?
The nervous system and endocrine system working together harmoniously
What is unique about the nervous system in comparison to the endocrine system?
- Fast
- Uses impulses to send messages
- Brain, spinal cord and nerves
- Uses the central and peripheral nervous system
What is unique about the endocrine system in comparison to the nervous system?
- Slow
- Uses hormones to send messages
- Glands
- Travles through the blood stream
What is similar between the endocrine and nervous system?
- React to stimuli
- Maintain homeostasis
- Send messages
- Hypothalamus is the link between the two
What is feedback in the control system?
A system that helps maintain a regulated variable at its set point (range)
What is a regulated variable?
The part of homeostasis that is being regulated
What is a set point?
The ideal value (range) for the regulated variable
What is the afferent pathway?
The pathway that carries info to the controller
What is the efferent pathway?
The pathway that carries info from the controller
What is the feedback loop structure?
Sensors
Control centre
Effectors
Controlled variable
Repeat
What is a negative feedback loop?
A response in the opposite direction to the detected change
What is a positive feedback loop?
A response in the same direction to the detected change
What are feed-forward control systems?
Systems that are anticipatory that prevent negative impacts on homeostasis
What is an example of a feed-forward control system?
A dry mouth stimulates drinking, you are not dehydrated yet
What is the difference between a fever and hyperthermia?
Fever is beneficial and the set point is increased to increase the body’s heat to combat infection
Hyperthermia is no beneficial and the set point does not change and body tries to combat increased temp
What are reflexes?
Involuntary reactions to stimulus that are usually protective
What is extracellular fluid?
Fluid outside of cells
What are the two types of extracellular fluids and where can they be found?
Interstitial fluid - around cells
Plasma - blood vessels
What is intracellular fluid?
Fluid found inside the cell
What fraction of water is within cells?
2/3
What fraction of water is outside of cells?
1/3
What percentage of
What percentage of ECF is found in blood?
20%
What is the different composition of ICF and EFC?
ICF has high potassium concentration and ECF has high sodium concentration
