Biology Topic 5: Homeostasis Flashcards
(22 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 is crucial for maintaining enzyme action and all cell functions.
What are the three key areas controlled by homeostasis in the human body?
- Blood glucose concentration
- Body temperature
- Water levels
What are the components of automatic control systems in homeostasis?
- Receptors (detect stimuli)
- Coordination centres (process information)
- Effectors (bring about responses)
What is the function of the central nervous system (CNS)?
To coordinate the response of effectors which may be muscles contracting or glands secreting hormones.
What is a reflex action?
An automatic and rapid response that does not involve the conscious part of the brain.
What structures are involved in a reflex arc?
- Sensory neurone
- Synapse
- Relay neurone
- Motor neurone
What are the main parts of the brain and their functions?
- Cerebral cortex
- Cerebellum
- Medulla
What are the methods used by neuroscientists to investigate brain function?
- Studying patients with brain damage
- Electrically stimulating different parts of the brain
- Using MRI scanning techniques
How does the eye accommodate to focus on near objects?
- Ciliary muscles contract
- Suspensory ligaments loosen
- Lens becomes thicker and refracts light rays strongly
What is the process of adaptation in the eye?
Adjusting to dim light.
What are the common defects of the eye?
- Myopia (short sightedness)
- Hyperopia (long sightedness)
How does the body respond when the temperature is too high?
- Blood vessels dilate (vasodilation)
- Sweat is produced from sweat glands
How does the body respond when the temperature is too low?
- Blood vessels constrict (vasoconstriction)
- Sweating stops
- Skeletal muscles contract (shiver)
Fill in the blank: The thermoregulatory centre in the brain contains receptors sensitive to _______.
the temperature of the blood
What is accommodation in terms of eye function?
The process of changing the shape of the lens to focus on near or distant objects.
What is the role of the retina in the eye?
To contain receptors sensitive to light intensity and colour.
What is the function of the optic nerve?
To transmit visual information from the retina to the brain.
What structure of the eye protects and shapes it?
Sclera
What is the function of the cornea?
To refract light rays entering the eye.
What do ciliary muscles do?
They help change the shape of the lens for focusing.
What is the function of the suspensory ligaments in the eye?
To hold the lens in place and assist in changing its shape.
True or False: Reflex actions involve the conscious part of the brain.
False
