B10 The Nervous System Flashcards
Homeostasis
The regulation of internal conditions of a cell or organism to maintain optimum conditions for function in response to internal and external changes
Internal conditions that need to be controlled
Water levels Blood glucose concentration Body temperature (37) Carbon dioxide levels Blood pH Ion levels
How is homeostasis controlled
Automatic control systems
The 3 Automatic control systems
Central Nervous System (CNS)
Peripheral Nervous System (PNS)
Endocrine System
CNS
Brain and spinal chord
PNS
All nerve cells
Stimulus
A change in the environment of an organism
Sense organs
Stimuli are picked up by sense organs
Touch, smell, hear, see, taste
The 3 types of neuron
Sensory neurons
Relay neurons
Motor neurons
Sensory neuron
convert external stimuli from the organism’s environment into electrical impulses.
Relay neuron
Connect sensory and motor neurons
Motor neurone
Nerve cells forming part of a pathway which impulses pass from the brain or spinal cord to a muscle or gland.
Pathway of nerve impulses in a conscious reaction
Stimulus-Receptor-Sensory neurone-CNS-Relay -Motor neurone-Effector-Response
Synapse
A gas between 2 neurones
Reflex action
An unconscious reaction to a stimulus
Pathway of a nerve impulse
Stimulus-Receptor-Sensory neurone-CNS-Relay neurone-Motor neurone-Effector- Response
The Endocrine (hormonal) system
The second control system of the body
The function of the endocrine system
It is made up of different glands which produce hormones directly into the bloodstream. These hormones travel to target organs and bind to receptors. A response occurs
Pathway of the Endocrine system
Gland-Hormone-Bloodstream-Target organ-response
What is a synapse
A minute gap between neurones, across which impulses pass by diffusion of a neurotransmitter.
