Chapter 10 - The Human Nervous System Flashcards
What is homeostasis?
Regulations of internal conditions of a cell or organisms to maintain optimum conditions for function, in response to internal or external changes
Why is homeostasis important?
For maintaining optimal conditions for enzyme action and all cell functions
Examples of homeostasis in the human body
Controls blood glucose concentration, body temperature, and water levels
A change in the environment
Stimuli
eg change in temperature
Cells that detect changes in the environment
Receptors
eg fingertip cells
Areas that receive and process the information from the receptors
Coordination centers
Brain and spinal cord
Muscles or glands that bring about responses to the stimulus that has been received
Effector
What uses electrical impulses to enable you to react quickly to your surroundings and coordinate your behavior
The Nervous System
Where do impulses go after receptors
Along sensory neurones to the brain or spinal cord (CNS)
the brain coordinates the response and impulses are sent along a motor neuron to the effector organs
The neurone that connects the sensory neuron to the motor neurone
Relay Neurone
Advantages or reflex action
Automatic and rapid
Do not require conscious parts of the brain
The main stages or a reflex action
Stimulus –> receptors –> sensory neurons –>relay neurones –> motor neurones –> effector –> response
Examples or reflex actions
Breathing, digestion, and avoiding danger
Synapse
Area between neurones where the electrical impulses diffuse across in a chemical
Area of the brain involved with consciousness and intelligence, memory and language
The cerebral cortex
Area of the brain involved in coordinating muscular activity and balance
The cerebellum
Area of the brain concerned with unconscious activity such as controlling the heartbeat and breathing and the movements of the gut
Medula
How do scientists map the brain
By studying patients with brain damage, by electrically stimulating different areas of the brain and by using MRI scanning techniques
Which parts of the eye are responsible for focusing on objects that are close to you?
Ciliary muscles, suspensory ligaments, and the lens
What does the cornea do?
Protects the eye
and refracts light
How does your eye focus on something close to you?
Ciliary muscles relax, tightening the suspensory ligaments making the lens fatter so that the light refracts more
What is myopia?
Someone with short sight (can focus on near objects)
lens is too curved or a particularly long eyeball
What is hyperopia?
someone with long sight (can focus on far objects)
lens isn’t curved enough or a particularly short eyeball
Three ways to overcome myopia and hyperopia
Contact lenses
laser eye surgery
replacement lenses
the two types of lenses and their functions
convex - same as having a fat lens
concave - same as having a thin lens
What is accommodation?
the process of changing the shape of the lens to focus on a near or distant object
