Homeostasis and the nervous system Flashcards
Maintaining the correct conditions in the body for it to function correctly is known as?
Homeostasis
State the three key conditions in the body controlled by homeostasis
1 Body temperature
2. Blood glucose concentration
3. Water balance
What is homeostasis?
Maintaining the correct conditions in the body for it to function correctly
Much of the automatic involuntary regulation of homeostasis in the body is made by two body systems, identify them.
- nervous system- sending nerve impulses
- endocrine system- producing hormones
There are 3 key parts to the nervous system - identify them
- Receptor
- Central nervous system
3 Effector
Describe the role of an effector in the nervous system
An effector causes a response by either moving the body or secreting a hormone
Describe the role of an receptor in the nervous system
They detect changes inside or outside of the body and respond by generating an electrical response.
Describe the role of the central nervous system
Receives impulses from the receptors and coordinates a response by sending impulses to the effectors.
What makes up the Central nervous system (CNS)
The brain and the spinal cord
How are messages transmitted along nerve cells
by electrical impulses
What is the role of the myelin sheath around a long nerve cell
It insulates the cell allowing faster electrical impulses up to 250mph
Identify the 5 sense organs
Eyes
Ears
Nose
Tongue
Skin
What stimuli do we receive in order to see
Light waves
What stimuli do we receive in order to hear
Sound waves
What stimuli do we receive in order to taste
Chemicals in food
What stimuli do we receive in order to smell
Chemicals diffusing through the air
What stimuli do we receive in order to touch
pressure, itching, pain and temperature
Identify the three types of neurone
Sensory, motor and relay
What are nerves comprised of?
Bundles of neurones
Describe the role of a sensory neurone
One which carries a nerve impulse from a receptor towards the CNS
Describe the role of a relay neurone
One which carries a nerve impulse within the CNS, the brain and spinal cord
Describe the role of a motor neurone
One which carries a nerve impulse from the CNS to an effector (muscle or gland)
Describe the pathway through the nervous system from receiving a stimulus to responding to it.
Stimulus –> receptor –> sensory neurone –> relay neurone –> motor neurone –> effector –> response
What is a dendrite?
The branched beginnings of a neurone which detect the chemical neurotransmitters and start another electrical impulse
What is a synapse?
The gap between the axon of one nerve and the dendrites of another
What is an axon?
A nerve fibre which conducts electrical signals called impulses
What happens to a nerve impulse when it reaches a synapse?
The electrical signal spreads out at the end of axon into the root like ends of the cell.
At the tips of these the electrical impulses are converted into chemical signals called neurotransmitters.
These diffuse across the synapse and bind to receptors in the dendrites of the next neurone.
It triggers an electrical impulse which travels along the neurone until it reaches the next synapse and so on.
What is a reflex response
It is a rapid automatic response to a stimulus such as pain or heat which does not reach the brain.
Other reflex responses include regulating heart rate and dilating or contracting the pupil to let light into your eyes.
How is the reflux arc when you touch something very hot different from other neural pathways
The pathway of neurones in the reflex arc does not include relay neurones immediately transmitting information to the brain.
Instead when a sensory neurone transmits a pain stimulus to a relay neurone in the spinal cord it first sends an impulse along the motor neurone to the muscle effector to move away from the heat.
What is the difference between a reflex action and a conscious decision?
Conscious decisions involve relay neurones in the brain before motor neurones send impulses to the effectors wheras reflex actions are automatic and the signal is generated from the spinal cord.
