Wk 14 REMEMBER Flashcards
CNS-Central Nervous System consists of:
- the brain
- the spinal cord
Functions of the CNS: to process and coordinate
- sensory data: from inside and outside the body
- motor commands: control activities of peripheral organs (eg skeletal muscle)
- higher functions if the brain: intelligence, memory, learning, emotion
Nervous system - master controller
Relieves sensory input which goes to the integration centre = in spinal cord, brain, learning, emotion etc
Divisions & organs of the nervous system
Two main divisions:
CNS-Central Nervous System
PNS-Peripheral Nervous System (eyes, ears and touch)
Neural Tissue
2 principal kinds of cells:
*neurons (transmit)
*neuroglia (or glial cells) (‘nerve glue’ fill in all space between neurons) 10x more numerous than neurons
Neurons (Nerve cells)
- Dendrites-bring in other messages
- Axon-away messages
Nerve body, lots of extensions (dendrites) and second largest is called axon
Nerve cll body (perikaryon or soma)
- contains the nucleus and a nucleolus
- is the major bio synthetic centre ***
- is the focal point for the outgrowth of neuronal processes
- no centrioles (cannot undergo mitosis)
- has well-developed Nissl bodies (rough ER)
- contains an axon hillock -cone shaped area from which the axon arises
Processes
- arm like extensions from the soma
- axons that take the message away from cell body
- dendrites bring messages too
- axons called “Tracy’s” in the CNS and ‘nerves’ in the PNS
Axon functions:
- generate and transmit action potentials, towards axon terminal and away from cell body
- secrete neurotransmitters from the atonal terminals
Classification of Neurons by Structure
Bipolar neuron: vision. Dendrites join together to make axon. ‘One pole’
Unipolar neuron: ‘one point’ in unipolar, sensations eg.skin
Multipolar neuron: most neurons are multipolar, ‘multiple poles’,
The human brain
- 2% of weight of body
- average weight 1400g
- 60% mass of brain is lipids
- white matter = brain
- blood vessels held in place by protected layer called maninges?
- normal 750 cc’s to 2100 cubic metres
The Human Brain (superior view)
- top = anterior
- bottom = posterior
- longitudinal fissure (anterior left)
- cerebral veins and arteries covered by arachnoid
- left cerebral hemisphere
- frontal lobe (anterior right)
- parietal lobe
- right cerebral hemisphere
- occipital lobe
- sulci = deep ridges
- gyro = either side of the brain
- 2/3 mm is grey mater (nerve)
3 protective layers:
- dura mater, means tough mother (like shoe leather)
- pia mater, gentle meaning
- arachnoid mater, spider mother meaning
The human brain
Cerebellum - balance and coordination. Gives you the drunk effect.
Lobes of the Cerebral Hemispheres 5 lobes: * frontal (front of head) * temporal lobes (above/behind ear) * occipital (back of head where bump is) * parietal (front heading to back) * insula (in further) Named after the bone they lay under (Check photo of this)
Cortex - 2/4mm thick
- cortex (Grey mater) - nerve cells bodies with supportive tissue
- grey mater follows sulci around the edges
- Precentral gyrus and post central gyrus LEARN WHAT THEY DO ETC
The cerebrum - functional areas
- CHECK PHOTO but dont need to know except
- injuries by people have made us learn about the brain
- identify areas of brain damage and seeng what functions they have lost
The cerebrum - functional areas (exam picture)
- Precentral gyri - between frontal lobe and priorital lobe, long groove named the central sulcus. This motor area is with percent dal gyrus
- postcentral gyri - primary sensory cortex
Cerebral Nuclei (The Basal Ganglia) * Corpus callosum - 50% to 2/3 thicker in females
The Diencephalon
- thalamus - important relay centre
- Hyperthalamus - hormone centre
The Brainstem * Midbrain - top of stem * pons - round part half way down * medulla oblongata - below pons Check photo?
The spinal cord
- foramen magnum
- conus medullaris
- filum terminate
- cervical enlargement (top below foramen magnum)
- lumbosacral enlargement (lower back)
Spinal Nerves
- dorsal roots (top dark bit)
- ventral roots (vertical root from spine)
- rootlets (tiny roots on spine)
What parts make up the central nervous system?
Brain and spinal cord
Which layer of the brain contains 2/3’s of the brains nerve cells?
The cerebral Cortex - the grey matter
- Large cerebral hemispheres have important functions such as learning, memory, comprehension, perception of sensory input
- cerebellum functions are equilibrium and coordination of movement
Outer surface = grey matter. Grey because of the presence of the nerve cell bodies.
Inner white matter is white because it consists of myelinated axons and oligodendrocytes
Spinal cord - grey matter of the spinal cord is inner and outer is white
