Gross organisation of the Nervous System Flashcards
Despite nervous systems appearing slightly different across animal orders…
they are composed of key shared features
What nervous system of Sponges and jellyfish have?
a nerve net
what’s the difference neuronally between vertebrates and invertebrates?
Invertebrates have a ventral nerve cord, compared with a dorsal cord in vertebrates
What brain regions do all vertebrates have? (5)
olfactory bulb, cerebral hemispheres, cerebellum, optic tectum, medulla oblongata
what brain region do only mammals have?
Neocortex
What’s the Nervous system divided into?
Peripheral and Central nervous sytsem
What is the central nervous system divided into?
Spinal cord and Brain
What is the peripheral nervous system divided into?
Autonomic nervous system and Somatic nervous system
what is the autonomic nervous system divided into?
Sympathetic and Parasympathetic nervous system
What’s the somatic nervous system divided into?
Afferent and efferent nerves
What are ventricles?
Hollow spaces in the brain filled with Cerebrospinal Fluid (CSF)
What’s the function of ventricles?
- cushion the brain
- maintain chemical stability
- remove waste products
What is the spinal cord?
- tubular, long structure made up of nervous tissue extending from the brain to the lower back
- Protected by spinal column and surrounded by meninges and CSF
What’s the purpose of the spinal cord?
it’s the primary channel for messages from skin, joints and muscles to and from the brain
What type of neurons do the dorsal roots of the spinal cord contain?
Sensory, afferent neurons
what type of neurons do the ventral roots of the spinal cord contain?
motor, efferent neurons
what matter does the spinal cord contain (2)
grey and white
what is grey matter?
neuron cell bodies
what is white matter?
myelinated axons
Which is the oldest part of the brain?
brainstem
what is the function of the brainstem?
controls vital functions
what 4 parts does the brainstem contain?
- midbrain (mesencephalon)
- pons
- medulla
- cerebellum
What is the pons?
a swelling coming out from the ventral surface of the brainstem
what’s the function of the pons?
important relay between the cerebellum and cerebral cortex
What’s the function of the medulla?
control of blood pressure and respiration
what is the function of the cerebellum?
movement control
what is the cerebellum connected to?
cerebrum and spinal cord
How many neurons does the cerebellum contain?
more than both cerebral hemispheres (lots in a small space)
what do diseases of the cerebellum normally cause?
ataxias- aberrant movement coordination (similar to that seen from alcohol as alcohol effects the cerebellum)
Can humans live without a cerebellum?
yes
What is the mesencephalon commonly known as?
midbrain
what’s the function of the mesencephalon? (2)
- linkages between components of motor systems
- eye movement
What does the diencephalon contain?
Thalamus and Hypothalamus
What is the function of the thalamus? (2)
relay and gating
what’s the function of the hypothalamus? (2)
homeostasis and reproduction
How is the cerebral cortex divided?
into left and right hemispheres along a sagital fissure
what is the function of the cerebral cortex? (3)
voluntary actions, cognition, perception/awareness
how many layers is the mammalian cerebral cortex?
6- most complex
What does the number of neurons in the cerebral cortex relate to?
intelligence
what’s the purpose of cortical folding in the cerebral cortex?
to increase the SA, therefore increasing cerebral neurons in the space
what are each cerebral hemisphere divided into?
lobes
how many cerebral lobes?
4
what are the 4 cerebral lobes?
frontal, parietal, temporal, occipital
what are the 3 layers of cells of the embryo?
- endoderm
- mesoderm
- ectoderm
What does the endoderm form into?
linings and organs
what does the mesoderm form into?
bones and muscles
what does the ectoderm form into?
nervous system and skin
how is the neural tube formed?
the neural plate folds
what does the CNS form from?
the walls of the neural tube
what does the PNS form from?
the neural crest
what causes spina bifida?
the failure of the posterior neural tube to close
what are 4 ways of imaging the brain?
- MRI
- CT
- fMRI
- PET
What does CT stand for?
Computed Tomography
what happens in a CT scan?
an X-ray source is rotated around the head within the plane of the desired cross-section.
on the other side, there are detectors sensitive to X-rays.
Information is fed into a computer, which uses an algorithm to construct an image.
what does the CT scan image show?
The gross organization of grey and white matter and ventricles in the living brain
what was MRI stand for?
Magnetic Resonance Imaging
Compare CT to MRI
MRI shows a more detailed map of brain w/o X-rays
How does an MRI work?
Uses information on how hydrogen atoms in the brain respond to perturbations of a strong magnetic field.
EM signals emitted are detected by an array of surrounding sensors to construct a map of the brain
What can a MRI image show?
A map of the entire brain
what are MRI and CT scans useful for?
detecting structural changes like swelling or tumours
what don’t MRI and CT scans show?
chemical/ electrical occurrences in the brain
What does PET stand for?
Positron Emission Topography
How is a PET done?
a radioactive solution containing atoms that emit positrons is introduced to the blood stream. Positrons are emitted wherever the blood goes
What does a PET scan show?
Where metabolic activity is occurring in the brain- which parts of the brain are active for different activities (live imaging)
what does fMRI do?
detects regions of more activity by measuring the ratio of haemoglobin to deoxyhaemoglobin
