B10 Flashcards
What doe homeostasis do
Homeostasis maintains optimal conditions for enzyme action and all cell functions.
What does homeostasis control in the body
blood glucose concentration
body temperature
water levels.
What are the control systems in homestasis
cells called receptors, which detect stimuli
coordination centres that receive and process information from receptors
effectors, muscles or glands, which bring about responses which
restore optimum levels.
How does the nervous system enable humans to react to their surroundings and coordinate their behaviour
stimulus - receptor - (passes along neurone cells as electrical impulses) - coordinator (CNS-brain) - effector - response
What do relay neurones do
Connect sensory neurone and a motor neurone
What are sensory neurones
The cells that carry impulses from sense organs to CNS
What are motor neurones
Are cells that carry info to the effectors
What is a synapse
Information from one neuron flows to another neuron across a synapse.
What does the cerebral cortex do
The cerebral cortex concentrates on consciousness, intelligence, memory and language.
What does the cerebellum
The cerebellum concentrates in coordinating muscular activity and balance.
What does the medulla do
The medulla concentrates on unconscious activities such as controlling heartbeat, movement of the gut and breathing
Some of difficulties of treating the brain damage and disease
As the brains very delicate and easily damaged, surgery is hard as every part of the brain is not fully understood, when treating brain disorders the drugs do not always pass through the membrane surrounding the brain.
How does eye focus on close objects
To focus on a near object:
• the ciliary muscles contract
• the suspensory ligaments loosen
• the lens is then thicker and refracts light rays strongly
How does eye focus on far objects
To focus on a distant object:
• the ciliary muscles relax
• the suspensory ligaments are pulled tight
• the lens is then pulled thin and only slightly refracts light rays.
myopia and hyperopia, why they happen
myopia (short sightedness) and hyperopia (long sightedness) in which rays of light do not focus on the retina.
