1. Neurobiology A.1 – A.3
Allison Bynum

2. A.1 Neural Development
Allison Bynum

3. A.1 – The neural tube of embryonic chordates is formed by infolding of ectoderm followed by elongating of the tube.
Neural folds converge
Neural plate elongates and thickens
The neural crest forms as the tube is forming
Neural tube is formed and the outer layer of the ectoderm becomes the epidermis

4. A.1 – Neurons are initially produced by differentiating in the neural tube.
Neuron differentiation
Neurons – carry the messages by electrical impulses
Glial cells – provide structural and nourishing support for neurons (also act as insulators(Myelin Sheath))

6. A.1 – Immature neurons migrate to a final destination.
Glial cells provide a way for the immature neurons to travel to destinations.
Maturation of the neurons occurs after the migration.

7. A.1 – An axon grows from each immature neuron in response to chemical stimuli.
Axon growth
CAMs help to attract axons to their targets
CAMs are released into the extracellular space.
Some signals from CAMs interfere with other axons and repel them.

8. A.1 – Some axons extend beyond the neural tube to reach other parts of the body.
Motor neurons – extend beyond the CNS to become the peripheral nervous system for voluntary movements

9. A.1 – A developing neuron forms multiple synapse.
Neurons try to form synapses with nearby target cells and test the connection.
The synapse is eliminated if it isn’t successful. (neural pruning)

10. A. 1 – Synapse that are not used do not persist. A
A.1 – Synapse that are not used do not persist. A.1 – Neural pruning involves the loss of unused neurons.
Neural pruning – the elimination of unused or unnecessary synapses

11. A.1 – The plasticity of the nervous system allows it to change with experience.
Brain plasticity – is the brain’s ability to change and adapt as a result of experience
Brain plasticity is higher in younger children and decreases with age. The adult brain is more resistant to change.

12. A.2 The Human Brain

13. A.2 – The anterior part of the neural tube expands to form the brain.
Nerve cells migrate to the outer edge of the neural tube and cause the walls to thicken.
The neural tube develops into the brain and spinal cord. The anterior end of the tube expands to form the cerebral hemispheres of the brain, while the posterior end forms the spinal cord and the other parts of the brain.

14. A.2 – Different parts of the brain have specific roles.
Part of the Brain
Function
Cerebral hemispheres
Higher complex functions/problem solving
Hypothalamus
Maintains hormone homeostasis and the pituitary gland
Cerebellum
Coordinates unconscious functions(not vital)/balance and movement
Medulla Oblongata
Controls automatic vital functions(heart beat and breathing)
Pituitary Gland
Hormone storage and secretion/controlled by hypothalamus

15. A.2 – The autonomic nervous system controls involuntary processes in the body using centers located in the brainstem.
Autonomic nervous system – is part of the peripheral nervous system; controls involuntary functions; regulates gland activities, smooth muscles, and the heart
The sympathetic and parasympathetic systems are divisions of the ANS.
Sympathetic
Parasympathetic
Important for emergencies
Returning to normal
“Fight or Flight” response
Relaxing
Noradrenaline
Acetylcholine
Excitatory
Inhibitory

17. A.2 – The cerebral cortex forms a larger portion of the brain and is more highly developed in humans than other animals.
Cerebral cortex – the thin layer of grey matter covering the cerebral hemispheres; contains 75% of the body’s neurons
Responsibilities include:
Reasoning
Language
Complex thought
Visual processing
Motor movement
Remembering
Speech

18. A.2 – The human cerebral cortex has become enlarged principally by an increase in total area with extensive folding to accommodate it within the cranium
The folds in the brain help to increase the surface area of the cerebral cortex to allow more neurons.
Parts of the cerebral cortex have specific functions.

19. A.2 – The cerebral hemispheres are responsible for higher order functions.
The cerebrum is responsible for the problem solving and higher thinking

20. A.2 – The left cerebral hemisphere receives sensory input from sensory receptors in the right side of the body and the right side of the visual field in both eyes, and vice versa for the right hemisphere.
Left hemisphere receives sensory info from:
Right eye
Right field of vision(some parts will cross over with left field of vision)
Right side of body
Right Hemisphere receives sensory info from:
Left eye
Left field of vision(some parts will cross over with right field of vision)
Left side of body

21. A.2 – The left cerebral hemisphere controls muscle contraction in the right side of the body, and vice versa for the right hemisphere.
The motor neurons for the left cerebral hemisphere connect to the muscles on the right side and vice versa.

22. A.2 – Brain metabolism requires large energy inputs.
Glucose is needed constantly for the brain because neurons cannot store it. The energy is used up very rapidly because of the mental activity.
Carbohydrates like fruits, vegetables, grains and dairy are some of the best sources for glucose.

23. A.3

24. Receptors detect changes in the environment.

25. Rods and cones are photoreceptors located in the retina.

26. Rods and cones differ in their sensitivities to light intensities and wavelengths.

27. Bipolar cells send the impulses from the rods and cones to ganglion cells.

28. Ganglion cells send messages to the brain via the optic nerve.

29. The information from the right field of vision from both eyes is sent to the left part of the visual cortex and vice versa.

30. Structure in the middle ear transit and amplify sound.

31. Sensory hairs of the cochlea detect sounds of specific wavelengths.

32. Impulses caused by sound perception are transmitted to the brain via the auditory nerve.

33. Hairs in the semicircular canals detect movement of the head.

34. Resources http://www.bodbot.com/Cognitive_Health.html