Functions Of The Nervous System Flashcards
What are the functions of the nervous system?
Sensation- taking information from the outside world, integration, initiation of motor activity
What do sense organs do?
Sense/take specific information from the external environment and turn it into an action potential
Eg ear turns vibrations of the air into action potentials
Sensory neurones respond to temperatures, pain etc turning external stimuli into APs
What does the PNS include?
All nerves and ganglia (collection of cell bodies of neurones) outside brain and spinal cord.
How does the brain change during development?
- CNS initially develops as a simple hollow tube
- the cerebral hemispheres develop as outgrowths in ether side from the cranial end of this tube
- as they grow they sweep back over the surface of the tube, hiding the central core of the developing brain
What does the brain comprise generally?
A central core and two cerebral hemispheres
What are the types of 31 spinal nerves?
Cervical (8) thoracic (12) lumbar (5) sacral (5) coccygeal (1)
Why are spinal nerves ‘mixed’?
They contain sensory and motor axons, associated with a defined region in the body
What are cranial nerves?
12 pairs of highly specialised nerves extending from the base of the brain through the cranium to the periphery - concerned with head and neck
What cranial nerves are involved in eye movements?
Oculomotor, Abducens, trochlear
Why are motor neurones easiest to study + most understood?
They send axons outside the NS, and the targets of them are really large (eg muscle) so relatively easy to identify subsets of motor neurones
What does the grey matter contain?
Predominately cell bodies, some axons
What does the white matter contain?
Axons connecting spinal cord to the brain and vice versa
What’s located in the dorsal root ganglion?
Cell bodies of afferent sensory neurones - their single axon divides into peripheral and central branches
Explain the knee jerk effect/ patellar reflex:
Sharp tap on patellar tendon (below kneecap) slightly stretches the quadriceps, stretch receptors cause an AP to be fired, causing motor neurones to fire an AP, causing the contraction of the muscle which tends to straighten the leg in a kicking motion
How do we know about the different regions in the brain having different functions?
Tumours, bullets in the head affecting certain functions of the body
MRI scans
Placing electrodes on the brain and stimulating different areas