Biology Chapter 12 (Coordination and Response) Flashcards
Define stimuli?
Changes in an organisms environment is called stimuli
Define receptors?
Cells that sense the stimuli
How do organisms respond to stimuli?
Using Effectors
Why do Animals need a more effeective response?
As they need to respond quickly to protect thmselves and to catch food.
Name 2 methods of sending information from receptors to effectors?
- Nerve receptors and nerve makeups of nervous system
- By means of hormones which are a part of Endocrine system
Define sensitivity?
The ability to detect stimuli and carry out responses
How are signals transfered in the nervous system?
Electrical impulses
How are signals transferred in Endocrine system?
Using Hormones
What are the two types of nervous systems?
- Central nervous system
- Peripheral nervous system
What are the two nervous systems under peripheral nervous system?
- Autonomic nervous system
- Somatic nervous system
What are nervous system cells made of?
Neurons
What is the longest fibre in Nervous cells?
Axon- more than a meter long
What are the shorter fibres in nervous cell called?
Dendrites and Dendrons
Function of dendrites?
Pick electrical signals from other neurons nearby called impulses, cell body, along with axon
Define Myelin?
A layer of fat and protein that surrounds the nerve fibres of active animals, like mammals.
Function of Myenlin?
It insulates the nerve fibres so that impulses could be sent much faster
What are the 3 types of neurons?
- Sensory neuron
- Relay Neuron
- Motor neuron
Describe the basic function of nervous system?
The sensory neuron detects the stimuli and sends those impulses to the CNS (Central Nervous System). The CNS then send a signal to the Motor Neuron which makes it contract and move the muscle where the stimuli happened.
What are the 2 types of Nervous action?
- Voluntary actions
- Involuntary actions
Define Voluntary action?
An action that we do out of our will or we do it conciously.
Define Involuntary action?
An action which occurs without out conscious choice or will. Ex(Breathing, Heart beat, Blinking)
Function of Sensory Neurone?
picks impulses from the sensory receptor and sends it to the spinal cord along the axon of the receptor cell.
Function of Relay Neurons?
They pass the impulses onto the effector.
Define Reflex arc?
The pathway in which the nerve impulse passes along Sensory, Relay and Motor neurone
Define reflex action?
Reflex action is also an involuntary action. It is a nearly instantaneous movement in response to stimuli. It is an automatic action.
Define Synaptic clefts?
The space in between the axon of on neuron and the dendrites of another.
Define receptors.
Cells or group of cells that detect stimuli.
Example:
i.)Eyes: cones and rods in the retina are receptors.
Define conjunctiva.
A thin, transparent membrane in font of the eyes helps to protect parts behind it.
How is conjunctiva kept moist?
By the tear glands
Define Retina.
A tissue at the back of the eye that contains receptor cells that respond to light
Define Fovea.
Part of the retina packed with rods and cones for vision.
Define blind spot.
Where the optic nerve leaves the retina, lack of rods and cones results in no image being made when light fall on it