Homeostasis 1 Flashcards
(21 cards)
What is the definition of homeostasis?
Maintenance of a consistent internal environment or a steady state when the external environment changes.
From the Greek ‘homoios’ and ‘stasis’, meaning ‘staying in the same place’.
What are the three functional components of homeostatic control systems?
- Receptors
- Control centre
- Effectors
What is a stimulus in the context of homeostasis?
A change in the internal or external environment that can threaten homeostasis.
Examples include drop in environmental temperature, increase in blood sugar concentration, etc.
What types of sensory receptors exist?
- Chemoreceptors
- Thermoreceptors
- Mechanoreceptors
- Photoreceptors
- Nociceptors
What do exteroreceptors detect?
External stimuli, usually located close to the surface of the body.
What is the function of interoreceptors?
Detect internal states like blood pressure and blood chemistry.
Which part of the body is most often the control centre in homeostasis?
The brain, often in the hypothalamus.
What is the role of the effector in homeostasis?
Responds to the signal from the control centre to counteract the initial change.
What happens to muscles when the temperature drops?
Muscles contract and relax rapidly, causing shivering to increase metabolic heat production.
What response do sweat glands make when the temperature rises?
They begin secreting perspiration, which evaporates from the skin, cooling the body.
How does the pancreas respond when blood sugar concentration rises?
Produces insulin, prompting muscle and liver cells to take up glucose from the blood.
What is the mechanism through which homeostasis is achieved?
Negative feedback loops.
What occurs in a negative feedback loop?
Receptors detect a change, and effectors work to reverse the direction of the change to achieve equilibrium.
What systems are involved in internal communication for homeostasis?
Nervous and endocrine systems.
What is an example of a positive feedback loop?
Childbirth, blood clotting, milk production.
What is the primary difference between negative and positive feedback loops?
Negative feedback loops reverse a change, while positive feedback loops promote a change.
What happens when the concentration of a substance in the blood is too high?
A negative-feedback loop will work to lower it.
What is the role of the endocrine system in maintaining homeostasis?
Releases hormones in response to changes in internal or external stimuli.
Which systems work together to maintain homeostasis?
The nervous system and endocrine system.
Fill in the blank: Homeostasis is achieved via _______.
[negative feedback loops]
True or False: Most feedback loops in biological systems are positive.
False
