B10 - The Human Nervous System Flashcards
Homeostasis
- regulation of internal conditions of a cell/organism
- to maintain optimum conditions for function
- in response to internal and external changes
Conditions controlled internally
body temperature
water content of body
blood glucose concentration.
Automatic control system
Nervous and hormone shstem
Importance of homeostasis
maintaining optimum conditions for enzyme activity
Receptors
cells that detect changes in the internal and external environment
stimuli
changes that receptors detect
receptors are apart of which systems
nervous and hormone systems
coordination centres
areas that receive and process the info from receptors
eg of coordination centres
brain
spinal cord
pancreas
effectors
muscles or glands that bring about responses to the stimulus that has been received
-restore conditions
nervous system
carries electrical signals that travel fast
nervous system process - detection
-receptor detects stimuli
-sends impulse down neurones
neurones
special cells
-carry impulses to CNS
nerves
thousands of bundled neurones
central nervous system
made from brain and spinal cord
sensory neurones
-cells that carry impulses from sensory organs to CNS
motor neurones
-carry impulses from CNS to sense organs/ body
-causes effectors to respond
effector - muscle reaction
-muscles contract
effector - gland reaction
-glands secrete chemical substances
order of nervous system process
stimuli -> receptor-> CNS -> effector
required practical
-measure reaction times
-use ruler drop test
reflexes
rapid automatic responses of nervous system that don’t involve conscious thought
eg of reflexes
breathing
digesting food
reflexes involve
-sensory neurone
- relay neurone
-motor neurone
relay neurone
connect sensory and motor neurones
-found in CNS
process of reflexes
stimuli -> receptor -> sensory neurone
->relay neurone ->motor neurone
-> effector organ neurone
reflex arc
process of reflex action
-bypasses conscious areas of brain
- leads to shortest path taken
synapses
-physical gaps between neurones
passing over synapses process
-chemical is released
-chemical diffuses through gap
-received by receiving neurone
- triggers new impulse
diffusion of chemical across synapse is slower than ..
impulses travelling in neurones
reflex arc in detail
-impulse arrives at synapse with relay neurone
-chemical is released and diffuses across to relay neurone
-sets off new impulse to rely neurone
-synapse between relay and motor is crossed = new impulse
cerebral cortex
-concerned with:
consciousness
intelligence
memory
speech
meninges
protective membranes around brain
cerebellum
-concerned with coordinating muscular activity and balance
medulla
-concerned with unconscious activities
-eg breathing
hypothalamus
controls body temp
Scientific advancements
-map brain to their functions by studying brain damage
-electrically stimulating regions of brain
-by MRI scans
