Homostaisis Flashcards
(19 cards)
What is homeostasis?
The regulation of the internal conditions of a cell or organism to maintain optimum conditions for function in response to internal and external changes.
Homeostasis maintains optimal conditions for enzyme action and all cell functions.
Which conditions are controlled by homeostasis in the human body?
- Blood glucose concentration
- Body temperature
- Water levels
These automatic control systems may involve nervous responses or chemical responses.
What are the components of all control systems in homeostasis?
- Receptors
- Coordination centres
- Effectors
Receptors detect stimuli, coordination centres process information, and effectors bring about responses to restore optimum levels.
What is the role of the nervous system?
Enables humans to react to their surroundings and coordinate their behaviour.
What is the central nervous system (CNS)?
The brain and spinal cord.
What is the pathway of information in the nervous system?
Stimulus → Receptor → Coordinator → Effector → Response.
What characterizes reflex actions?
They are automatic and rapid; they do not involve the conscious part of the brain.
What structures are involved in a reflex arc?
- Sensory neurone
- Synapse
- Relay neurone
- Motor neurone
Understanding these structures helps explain the function of reflex actions.
What is the function of the cerebral cortex?
Controls complex behaviour.
What are the main regions of the brain that students should identify?
- Cerebral cortex
- Cerebellum
- Medulla
Each region has specific functions.
What challenges do neuroscientists face when studying brain function?
The complexity and delicacy of the brain make investigating and treating brain disorders very difficult.
What does the eye contain that is sensitive to light?
Receptors sensitive to light intensity and colour.
What is accommodation in terms of the eye?
The process of changing the shape of the lens to focus on near or distant objects.
What happens to the ciliary muscles when focusing on a near object?
The ciliary muscles contract and the suspensory ligaments loosen.
What are the two common defects of the eye?
- Myopia (short sightedness)
- Hyperopia (long sightedness)
These defects occur when rays of light do not focus on the retina.
How are eye defects generally treated?
With spectacle lenses that refract the light rays to focus on the retina.
What is the role of the thermoregulatory centre in the brain?
Monitors and controls body temperature.
What occurs when body temperature is too high?
- Blood vessels dilate (vasodilation)
- Sweat is produced from sweat glands
These mechanisms promote energy transfer from the skin to the environment.
What occurs when body temperature is too low?
- Blood vessels constrict (vasoconstriction)
- Sweating stops
- Skeletal muscles contract (shiver)
