B10. The human nervous system Flashcards
What is the role of the human nervous system?
The role of the nervous system is to allow humans to detect changes in their surroundings and coordinate responses
What are receptor cells?
Receptor cells are cells that detect stimuli
Which two organs make up the central nervous system (CNS)?
The CNS is made up of the brain and the spinal chord
What are effectors?
Effectors are the parts of the body that respond to changes in the environment. They can be muscles or glands
Write a flow diagram to show the pathway of an electrical impulse through the nervous system
stimulus ➡ receptor ➡ sensory neurone ➡ CNS ➡ motor neurone ➡ effector ➡ response
What are reflex actions?
Reflect actions are automatic, rapid actions that do not involve conscious thougjt
Why are reflex actions important?
Reflex actions are important because they protect the body from harm
Write a flow diagram to represent a reflex arc
Stimulus ➡ receptor ➡ sensory neurone ➡ relay neurone ➡ motor neurone ➡ effector ➡ response
What is a relay neurone?
A relay neurone is a neurone within the CNS that connects sensory and motor neurones
What is the role of a motor neurone in a reflex arc?
Motor neurones in reflex arcs connect relay neurones with effectors
Which factors could be chosen as independent variables when investigating the effect of a factor on reaction time?
Caffeine intake
Environmental factors
Time since last meal
Hours of sleep
How can a ruler be used to measure reaction time?
A ruler can be used to measure reaction time by dropping it vertically from a set height with 0cm facing downwards and measuring the distance at which a volunteer catches it. The shorter the distance, this faster the reaction time
In an investigation into the effects of caffeine on reaction time, which variables should be controlled?
Environmental factors
The hand being used to catch the ruler
The height from which the ruler is dropped
The time between caffeine consumption and the ruler drop test
What is the role of the brain in the nervous system?
The role of the brain is to control complex behaviour, as well as regulating body functions
What is the role of the cerebral cortex in the brain?
The cerebral cortex is responsible for higher brain functions such as consciousness, intelligence, memory and language
Which body functions are regulated by the medulla in the brain?
Breathing
Heart rate
Digestion
Why is it difficult to study brain function and to treat damage in the brain?
The brain is delicate
Brain function is highly complex
The functions of different brain areas are interconnected so it is difficult to study regions in insolation
How can neuroscientists map brain function?
Studying patients with damage to known areas of the brain
Electrical stimulation of the brain and observation of response
MRI scanning
Where is the sclera of the eye?
The white layer that forms the outside of the eyeball
Define the term accommodation in the context of eye function
Accommodation is the process by which the lens of the eye changes its shape to focus on objects at different distances
What is the role of the ciliary muscle in accommodation?
The ciliary muscles contract or relax to change the shape during accommodation
What happens to the ciliary muscles, suspensory ligaments and lens when focusing on a near object?
The ciliary muscles contract
The suspensory ligaments loosen
This causes the lens to become thicker, increasing refraction of light for close vision
How does the eye adapt to deal with dim light?
The eye adapts to deal with dim light by dilating the pupil; this allows more light to enters the eye
Define the terms myopia and hyperopia
Myopia = short sightedness
Hyperopia = long sightedness
What causes short or long sightedness?
Short and long sightedness are caused by inability to focus the light onto the retina
How can short and long sightedness be treated?
Wearing spectacles that refract light correctly
Use of hard or soft contact lenses
Laser surgery
Replacing the lens of the eye
Which part of the brain monitors and controls body temperature?
The part of the brain that monitors and controls body temperature is the thermoregulatory centre
What is the role of receptors in the control of body temperature?
Receptors in the thermoregulatory centre monitor blood temperature
Receptors in the skin detect air temperature and send impulses to the thermoregulatory centre
How does sweating increase heat loss from the body?
Sweating increases heat loss when sweat evaporates from the skin surface. The evaporation of sweat transfer heat energy away from the skin
Define the term vasodilation
Vasodilation is a cooling mechanism in which diameter of skin arterioles increases. This increases blood flow to capillaries in the skin surface, transferring heat to the environment by radiation
How do blood vessels and sweat glands respond to an increased body temperature
Sweat glands release swear which cools the skin by evaporation
Skin arterioles undergo vasodilation increase blood flow to capillaries at the surface of the skin
How does shivering contribute towards temperature regulation?
Shivering occurs when body temperature is too low. The rapid muscle contractions generate heat, raising the core body temperature
